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Sample records for nispero seedlings manilkara

  1. Cambios ontogénicos en la morfología de plántulas de Manilkara zapota: análisis de sus implicaciones ecológicas Ontogenetic changes in seedling morphology of Manilkara zapota: analysis of ecological implications

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    Juan Antonio Cruz-Rodríguez

    2010-04-01

    Full Text Available En este trabajo se describen los cambios ontogénicos que se presentan en la morfología de plántulas de Manilkara zapota, uno de los árboles más abundantes de las selvas neotropicales. Estas plántulas presentan cambios morfológicos que se relacionan significativamente con sus probabilidades de supervivencia. La variación se describe a partir del registro y la observación de 552 plántulas con alturas menores a 35 cm, localizadas en una selva mediana subperennifolia en la parte central del estado de Veracruz. De cada individuo se registró presencia de cotiledones, altura, número de hojas, longitud y forma de las hojas, cobertura y área foliar específica (AFE. Con base en la forma de las hojas, se distinguieron 4 variantes: a plántulas con cotiledones; b plántulas con hojas elípticas; c plántulas con hojas oblongas, y d plántulas con hojas oblongolanceoladas. El tamaño de las hojas de la última clase fue de hasta 30 cm y duplica el tamaño de las hojas de los árboles adultos. El AFE mostró una correlación negativa con el tamaño de la hoja, lo que sugiere costos de construcción altos en las hojas grandes y explica su ausencia en los primeros años de vida. La formación de hojas grandes es un proceso discontinuo que depende de las reservas de la plántula y que permite aprovechar la escasa radiación prevaleciente en sotobosque.In this work the variability in seedling morphology of one of the most abundant neotropical trees, Manilkara zapota, is described. These seedlings display morphological changes significantly related with their survival probabilities. The variation is described from observations of 552 seedlings with heights less than 35 cm, in a subtropical rain forest in the central portion of the state of Veracruz. From each seedling we gathered the following data: presence of cotyledons, height, number of leaves, length and shape of the leaves, cover, and specific leaf area (SLA. Based on leaf shape, 4 seedling

  2. In vivo mucoadhesive strength appraisal of gum Manilkara zapota

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    Singh Sudarshan

    2015-09-01

    Full Text Available The mucilage (MMZ extracted from the seeds of Manilkara zapota(Linn. P. Royen syn. using maceration techniques was evaluated for mucoadhesive strength by various in vitro and in vivo methods. The result showed that mucoadhesive strength of seeds mucilage have comparable property toward natural and synthetic polymers such as Guar Gum and hydroxyl propyl methyl cellulose (HPMC E5LV under the experimental conditions used in this study. Briefly, it could be concluded that the seed mucilage of Manilkara zapota can be used as a pharmaceutical excipient in oral mucoadhesive drug delivery systems. Further, it may be appropriate to study the changes in these properties after chemical modifications.

  3. Pesticidal Evaluation of Manilkara zapota (L. against Tribolium castaneum (Herbst

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    Muhammad Abu Osman

    2014-02-01

    Full Text Available This paper presents the residual eff ects of Manilkara zapota (L. P. Royen plant against the red flour beetle, Tribolium castaneum (Herbst. Four doses, i.e., 1238.5, 619.25, 309.6 and 154.8 μg/cm2 of ethyl acetate extract of stem bark of Manilkara zapota were applied on larvae and adult beetles. The effectiveness of the plant extract was increased with the increase of exposure time and after 72 hrs of exposure, the maximum residual toxicity was observed with LD50 of 228.8, 281.1, 413.4, 423.7, 455.2, 498.7 and 526.5 μg/cm2 for first, second, third, fourth, fifth, sixth instar larvae and adults, respectively. The results of this study also demonstrated that the earlier instars were more sensitive to the extracts than those of late instars as well as adults.

  4. Pesticidal Evaluation of Manilkara zapota (L. against Tribolium castaneum (Herbst

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    Muhammad Abu Osman

    2011-06-01

    Full Text Available This paper presents the residual eff ects of Manilkara zapota (L. P. Royen plant against the red flour beetle, Tribolium castaneum (Herbst. Four doses, i.e., 1238.5, 619.25, 309.6 and 154.8 μg/cm2 of ethyl acetate extract of stem bark of Manilkara zapota were applied on larvae and adult beetles. The effectiveness of the plant extract was increased with the increase of exposure time and after 72 hrs of exposure, the maximum residual toxicity was observed with LD50 of 228.8, 281.1, 413.4, 423.7, 455.2, 498.7 and 526.5 μg/cm2 for first, second, third, fourth, fifth, sixth instar larvae and adults, respectively. The results of this study also demonstrated that the earlier instars were more sensitive to the extracts than those of late instars as well as adults.

  5. In vivo mucoadhesive strength appraisal of gum Manilkara zapota

    OpenAIRE

    Singh Sudarshan; Bothara Sunil B

    2015-01-01

    The mucilage (MMZ) extracted from the seeds of Manilkara zapota(Linn.) P. Royen syn. using maceration techniques was evaluated for mucoadhesive strength by various in vitro and in vivo methods. The result showed that mucoadhesive strength of seeds mucilage have comparable property toward natural and synthetic polymers such as Guar Gum and hydroxyl propyl methyl cellulose (HPMC E5LV) under the experimental conditions used in this study. Briefly, it could be concluded that the seed mucilage of ...

  6. Secondary Metabolites from Leaves of Manilkara subsericea (Mart.) Dubard

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    de Almeida, Fernanda Borges; Fernandes, Caio Pinho; Romao, Wanderson; Vanini, Gabriela; Costa, Helber Barcelos; França, Hildegardo Seibert; Santos, Marcelo Guerra; Carvalho, José Carlos Tavares; Falcão, Deborah Quintanilha; Rocha, Leandro

    2015-01-01

    Background: Manilkara subsericea (Sapotaceae) is a species widely spread in the sandbanks of Restinga de Jurubatiba National Park (Rio de Janeiro, Brazil). It is commonly known as “maçaranduba”, “maçarandubinha” and “guracica”, being used in this locality as food, and timber. However, M. subsericea remains almost unexplored regarding its chemical constituents, including secondary metabolites from the leaves. Objective: Identify the chemical constituents from the leaves of M. subsericea. Materials and Methods: Leaves were macerated with ethanol (96% v/v), and dried crude ethanolic extract was sequentially washed with the organic solvents in order to obtain an ethyl acetate fraction. Substances from this fraction were identified by different techniques, such as negative-ion electrospray ionization Fourier and 1H and 13C nuclear magnetic resonance (NMR). Fresh leaves from M. subsericea were also submitted to hydrodistillation in order to obtain volatile substances, which were identified by gas chromatograph coupled to mass spectrometer. Results: NMR1H and 13C spectra allowed for the identification of the compounds myricetin, quercetin, and kaempferol from the ethyl acetate fraction. The negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry mass spectrum also revealed the presence in this fraction of a polyhydroxytriterpene acid (pomolic acid), and some flavonoids, such as quercitrin, and myricitrin. In all 34 volatile compounds were identified by gas chromatography-mass spectrometry, including monoterpenes, sesquiterpenes, and long chain hydrocarbons. Conclusion: This study describes the first reports concerning the phytochemical information about leaves from M. subsericea. SUMMARY Manilkara subsericea fruits proved to be a rich source of triterpenes. However, no phytochemical studies were carried out with leaves. Thus, we described identification of volatile substances from its essential oils, in addition to

  7. Triterpene Esters and Biological Activities from Edible Fruits of Manilkara subsericea (Mart. Dubard, Sapotaceae

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    Caio P. Fernandes

    2013-01-01

    Full Text Available Manilkara subsericea (Mart. Dubard (Sapotaceae is popularly known in Brazil as “guracica.” Studies with Manilkara spp indicated the presence of triterpenes, saponins, and flavonoids. Several activities have been attributed to Manilkara spp such as antimicrobial, antiparasitic and antitumoral, which indicates the great biological potential of this genus. In all, 87.19% of the hexanic extract from fruits relative composition were evaluated, in which 72.81% were beta- and alpha-amyrin esters, suggesting that they may be chemical markers for M. subsericea. Hexadecanoic acid, hexadecanoic acid ethyl ester, (E-9-octadecenoic acid ethyl ester, and octadecanoic acid ethyl ester were also identified. Ethanolic crude extracts from leaves, stems, and hexanic extract from fruits exhibited antimicrobial activity against Staphylococcus aureus ATCC25923. These extracts had high IC50 values against Vero cells, demonstrating weak cytotoxicity. This is the first time, to our knowledge, that beta- and alpha-amyrin caproates and caprylates are described for Manilkara subsericea.

  8. In vitro antibacterial activity in seed extracts of Manilkara zapota, Anona squamosa, and Tamarindus indica.

    Science.gov (United States)

    Kothari, Vijay; Seshadri, Sriram

    2010-01-01

    Extracts prepared from seeds of Manilkara zapota, Anona squamosa, and Tamarindus indica were screened for their antibacterial activity by disc diffusion and broth dilution methods. Acetone and methanol extracts of T. indica seeds were found active against both gram-positive and gram-negative organisms. MIC values of potent extracts against susceptible organisms ranged from 53-380 μg/mL. Methanol extract of T. indica and acetone extract of M. zapota seeds were found to be bactericidal.

  9. Inhibitory Effect of Plant Manilkara subsericea against Biological Activities of Lachesis muta Snake Venom

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    Eduardo Coriolano De Oliveira

    2014-01-01

    Full Text Available Snake venom is composed of a mixture of substances that caused in victims a variety of pathophysiological effects. Besides antivenom, literature has described plants able to inhibit injuries and lethal activities induced by snake venoms. This work describes the inhibitory potential of ethanol, hexane, ethyl acetate, or dichloromethane extracts and fractions from stem and leaves of Manilkara subsericea against in vivo (hemorrhagic and edema and in vitro (clotting, hemolysis, and proteolysis activities caused by Lachesis muta venom. All the tested activities were totally or at least partially reduced by M. subsericea. However, when L. muta venom was injected into mice 15 min first or after the materials, hemorrhage and edema were not inhibited. Thus, M. subsericea could be used as antivenom in snakebites of L. muta. And, this work also highlights Brazilian flora as a rich source of molecules with antivenom properties.

  10. Inhibitory effect of plant Manilkara subsericea against biological activities of Lachesis muta snake venom.

    Science.gov (United States)

    De Oliveira, Eduardo Coriolano; Fernandes, Caio Pinho; Sanchez, Eladio Flores; Rocha, Leandro; Fuly, André Lopes

    2014-01-01

    Snake venom is composed of a mixture of substances that caused in victims a variety of pathophysiological effects. Besides antivenom, literature has described plants able to inhibit injuries and lethal activities induced by snake venoms. This work describes the inhibitory potential of ethanol, hexane, ethyl acetate, or dichloromethane extracts and fractions from stem and leaves of Manilkara subsericea against in vivo (hemorrhagic and edema) and in vitro (clotting, hemolysis, and proteolysis) activities caused by Lachesis muta venom. All the tested activities were totally or at least partially reduced by M. subsericea. However, when L. muta venom was injected into mice 15 min first or after the materials, hemorrhage and edema were not inhibited. Thus, M. subsericea could be used as antivenom in snakebites of L. muta. And, this work also highlights Brazilian flora as a rich source of molecules with antivenom properties.

  11. In vivo hypoglycemic study of Manilkara zapota leave and seed extracts

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    Saikat Ranjan Paul

    2015-03-01

    Full Text Available The hypoglycemic activity of pet-ether extracts of leaves and methanol extracts of seeds of Manilkara zapota was evaluated in the study. The oral glucose tolerance test was performed in mice treated with 2 mg/kg glucose solution and the blood glucose level was determined after 15, 30, 60, 90 and 120 min of administration. Alloxan (70 mg/kg was injected intravenously to induce diabetes in mice. The hypoglycemic study was carried out 7 days. In glucose tolerance test all extracts achieved significant p values (p<0.0001 at 60, 90 and 120 minutes compared to the glucose control. In hypoglycemic study all extracts started to reduce the blood glucose level rapidly even starting from the 2nd day of treatment and significant p values (p<0.0001 were achieved. So, the study evinced the hypoglycemic potency of the leave and seed extracts of M. zapota.

  12. Chemical and biological study of Manilkara zapota (L. Van Royen leaves (Sapotaceae cultivated in Egypt

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    Nesrin M Fayek

    2012-01-01

    Full Text Available Background: Manilkara zapota (L. Van Royen is an evergreen tree, native to the tropical Americas and introduced to Egypt as a fruiting tree in 2002. No previous study was reported on the plant cultivated in Egypt. Materials and Methods: In this study, the leaves of the plant cultivated in Egypt were subjected to phytochemical and biological investigations. The lipoidal matter was analyzed by GLC. Five compounds were isolated from the petroleum ether and ethyl acetate fractions of the alcoholic extract of the leaves by chromatographic fractionation on silica gel and sephadex, the structures of these compounds were identified using IR, UV, MS, 1 H-NMR and 13 C-NMR. The LD 50 of the alcoholic and aqueous extracts of the leaves was determined and their antihyperglycemic, hypocholesterolemic and antioxidant activities were tested by enzymatic colorimetric methods using specific kits. Results: Unsaturated fatty acids represent 32.32 % of the total fatty acids, oleic acid (13.95%, linoleidic acid (10.18 % and linoleic acid (5.96 % were the major ones. The isolated compounds were identified as lupeol acetate, oleanolic acid, apigenin-7-O-α-L-rhamnoside, myricetin-3-O-α-L-rhamnoside and caffeic acid. This is the first report about isolation of these compounds from Manilkara zapota except myricetin-3-O-α-L-rhamnoside, which was previously isolated from the plant growing abroad. The LD 50 recorded 80 g/Kg b. wt. for both the tested extracts, so they could be considered to be safe. They exhibited antihyperglycemic, hypocholesterolemic and antioxidant activities. Conclusion: The observed biological activities were attributed to the different chemical constituents present in the plant mainly its phenolic constituents.

  13. The Caatinga endemic Manilkara rufula possesses remarkable activity against Trichomonas vaginalis and Tritrichomonas foetus.

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    de Brum Vieira, Patrícia; Feijó Silva, Nícolas Luiz; Silva, Denise Brentan; Lopes, Norberto Peporine; da Silva, Alexandre Gomes; da Silva, Márcia Vanusa; Bastida, Jaume; Macedo, Alexandre José; Tasca, Tiana

    2017-02-01

    Tritrichomonas foetus infects the bovine urogenital tract, causing bovine trichomoniasis. Significant economic losses may occur due to infertility and abortion among cattle. Trichomonas vaginalis is the causative agent of trichomoniasis; the most common but overlooked non-viral sexually transmitted disease worldwide. Human and bovine trichomoniasis present treatment restrictions and efforts to identify new alternatives are essential. The present study evaluated the anti-trichomonads activities of seven fractions from northwest endemic plant Manilkara rufula. Flavonoids and condensed tannins were identified from these fractions by LC-DAD-MS/MS and MALDI-MS/MS. Altogether, the results demonstrated for the first time the structural description of tannins from leaves of M. rufula and the relation of these compounds with anti-T. vaginalis and anti-T. foetus activities. Overall, this report reveals the potential of M. rufula fractions against both parasites and shows new alternatives to treat the infection caused by trichomonads. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Inhibition of Ehrlich ascites carcinoma by Manilkara zapota L. stem bark in Swiss albino mice

    Institute of Scientific and Technical Information of China (English)

    M Abu Osman; M Mamunur Rashid; M Abdul Aziz; M Rowshahul Habib; M Rezaul karim

    2011-01-01

    To evaluate the antitumor activity of Manilkara zapota (M. zapota) L. stem bark against Ehrlich ascites carcinoma (EAC) in Swiss albino mice. Methods: The in vivo antitumour activity of the ethyl acetate extract of stem bark of M. zapota L. (EASM) was evaluated at 50, 100 and 200 mg/kg bw against EAC using mean survival time. After administration of the extract of M. zapota, viable EAC cell count and body weight in the EAC tumour hosts were observed. The animal was also observed for improvement in the haematological parameters (e.g., heamoglobin content, red and white blood cells count and differential cell count) after EASM treatment. Results: Intraperitoneal administration of EASM reduced viable EAC cells, increased the survival time, and restored altered haematological parameters. Significant efficacy was observed for EASM at 100 mg/kg dose (P<0.05). Conclusions: It can be concluded that the ethyl acetate extract of stem bark of M. zapota L. possesses significant antitumour activity.

  15. Evaluation of antioxidant and antimicrobial properties of Manilkara zapota L. (chiku) leaves by sequential soxhlet extraction method

    Institute of Scientific and Technical Information of China (English)

    Mital Kaneria; Sumitra Chanda

    2012-01-01

    Objective: Antioxidant and antimicrobial properties of Manilkara zapota L. (chiku) leaves was studied. Methods: The antioxidant property of different solvent extracts of Manilkara zapota L. leaves was evaluated by DPPH free radical, superoxide anion radical, hydroxyl radical scavenging activity and reducing capacity assessment, while the antimicrobial property was evaluated by agar well diffusion method against some of the tested food borne, spoilage, pathogenic and skin disease causing microorganisms. Results: The DPPH free radical scavenging activity of acetone extract was better than that of standard ascorbic acid and superoxide anion scavenging activity of acetone extract was better than that of standard gallic acid. It showed good reducing capacity assessment also. Maximum phenol content was also present in acetone extract thus supporting the idea that phenolic content and antioxidant activity show a direct correlation. Acetone extract showed significant antimicrobial activity amongst all the different solvent extracts. Conclusion:Result presented here suggest that acetone extract of M. zapota leaves possess strong antioxidant and antimicrobial properties, and it may be considered as an interesting and economic source of antioxidants and antimicrobics for therapeutic or nutraceutical industries and for food manufactures or pharmaceuticals.

  16. Regression models for estimating leaf area of seedlings and adult individuals of Neotropical rainforest tree species

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    E. Brito-Rocha

    Full Text Available Abstract Individual leaf area (LA is a key variable in studies of tree ecophysiology because it directly influences light interception, photosynthesis and evapotranspiration of adult trees and seedlings. We analyzed the leaf dimensions (length – L and width – W of seedlings and adults of seven Neotropical rainforest tree species (Brosimum rubescens, Manilkara maxima, Pouteria caimito, Pouteria torta, Psidium cattleyanum, Symphonia globulifera and Tabebuia stenocalyx with the objective to test the feasibility of single regression models to estimate LA of both adults and seedlings. In southern Bahia, Brazil, a first set of data was collected between March and October 2012. From the seven species analyzed, only two (P. cattleyanum and T. stenocalyx had very similar relationships between LW and LA in both ontogenetic stages. For these two species, a second set of data was collected in August 2014, in order to validate the single models encompassing adult and seedlings. Our results show the possibility of development of models for predicting individual leaf area encompassing different ontogenetic stages for tropical tree species. The development of these models was more dependent on the species than the differences in leaf size between seedlings and adults.

  17. In Vivo assay of Antidiarrhoeal activity of Methanoli c and Petroleum ether extracts of Manilkara Zapota Leaves

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    Manirujjaman

    2013-12-01

    Full Text Available The present study was aimed to investigate the possible antidiarrhoeal action of Methanolic extract (MEMZ and petroleum ether (PEMZ extracts of leaves of Manilkara zapota(Sapotaceae. The anti-diarrheal activity of MEMZ & PEMZ extracts was investigated by castor oil and Magnesium sulfate induced diarrhea in albino mice. The parameters ofthis study were number of diarrheal episodes and mean weight of stool of mice. The percentage protection in extracts treated animals showing diarrhea was compared with castor oil and Magnesium sulfate treated and loperamide treated animals. In the Castor oil induced method only the PEMZ extract, showed statistically significant (p0.05. These results indicate that the extracts possess antidiarrhoeal activity in mice.

  18. Seedling mycorrhiza

    DEFF Research Database (Denmark)

    Rasmussen, Hanne Nina; Rasmussen, Finn N.

    2014-01-01

    mycobionts suggest a derivation from a pathogenic relationship, and sister group comparison offers little support for derivation from other mycorrhizal relationships. A combination of in situ sowings and molecular identification of seedling mycobionts has established that a broad range of fungi besides...

  19. Trace element geochemistry of Manilkara zapota (L.) P. Royen, fruit from winder, Balochistan, Pakistan in perspective of medical geology.

    Science.gov (United States)

    Hamza, Salma; Naseem, Shahid; Bashir, Erum; Rizwani, Ghazala H; Hina, Bushra

    2013-07-01

    An integrated study of rocks, soils and fruits of Manilkara zapota (L.) (Sapotaceae) of Winder area have been carried out to elaborate trace elements relationship between them. The igneous rocks of the study area have elevated amount of certain trace elements, upon weathering these elements are concentrated in the soil of the area. The trace elements concentration in the soil were found in the range of 0.8-197 for Fe, 1.23-140 for Mn, 0.03-16.7 for Zn, 0.07-9.8 for Cr, 0.05-2.0 for Co, 0.52-13.3 for Ni, 0.03-8.8 for Cu, 0.08-10.55 for Pb and 0.13-1.8μg/g for Cd. The distribution pattern of elements in the rocks and soils reflected genetic affiliation. Promising elements of edible part of the fruit were Fe (14.17), Mn (1.49), Cr (2.96), Ni (1.13), Co (0.92), Cu (1.70) and Zn (1.02μg/g). The concentration of these elements in the fruits is above the optimum level of recommended dietary intake, probably due to this, disorder in the human health is suspected in the inhabitants of the area.

  20. Variabilidade no cpDNA em Manilkara huberi, espécie sob manejo sustentável na Amazônia brasileira cpDNA variability in Manilkara huberi, a species under sustainable management in the Brazilian Amazon

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    Vânia Cristina Rennó Azevedo

    2008-07-01

    Full Text Available O objetivo deste trabalho foi avaliar a existência de estruturação genética matrilinear em maçaranduba (Manilkara huberi. Foram avaliados 481 indivíduos adultos de M. huberi, distribuídos em 200 hectares de uma população natural na Floresta Nacional do Tapajós, Belterra, PA, e 88 regenerantes, com base na análise de nove microssatélites de cloroplasto e, de 96 indivíduos adultos, selecionados aleatoriamente na área de 200 ha, foi realizado o seqüenciamento de três regiões não codificadoras de cpDNA. Não foi detectado polimorfismo de seqüência. A análise da variabilidade haplotípica mostrou polimorfismo relativamente limitado, que resultou em 15 haplótipos, com diversidade genética total (hT de 0,898. Foi detectada a existência de estruturação genética significativa em distâncias de até 250 m, o que indica dispersão de sementes restrita e confirma o padrão de organização espacial da variabilidade genética mostrado pela análise de DNA nuclear, o que evidencia isolamento por distância e a necessidade de manutenção de grandes áreas de floresta primária para garantir a sobrevivência de maior número de subpopulações.The objective of this work was to evaluate the existence of matrilineal genetic structure in maçaranduba (Manilkara huberi. Evaluations were performed for 481 adult individuals of M. huberi, distributed in 200 hectares of a natural population in the Floresta Nacional do Tapajós, Belterra, PA, Brazil, and 88 plantules, based on nine chloroplast microsatellite loci and, of 96 individuals, selected randomly in the 200 ha area, it was carried out the sequencing of three intergenic regions from the cpDNA. No sequence polymorphism was detected. The analysis of the haplotypic variability showed a relatively low polymorphism, which resulted in 15 haplotypes, with total genetic diversity (hT of 0.898. Significant genetic structure until 250 m was detected, which indicates that seeds are restrictedly

  1. The Study of Seedlings

    NARCIS (Netherlands)

    Jacobs, M.

    1966-01-01

    ”The seedling represents the most critical stage in the life of a tree. Conditions of seeding and germination may be entirely favourable, and natural seedlings may appear in countless quantities at the beginning of the rainy season, only to disappear largely or entirely within a comparatively short

  2. Sobrevivência de espécies arbóreas plantadas em clareiras causadas pela colheita de madeira em uma floresta de terra firme no município de Paragominas na Amazônia brasileira Survival of seedlings planted in gaps after harvesting in a terra firme rain forest in Paragominas region in the Brazilian Amazonia

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    Jaqueline Macêdo Gomes

    2010-03-01

    Full Text Available Analisou-se a sobrevivência de mudas plantadas em 400 clareiras causadas por exploração florestal de impacto reduzido, em floresta de terra firme na Amazônia Oriental. Foram plantadas 3.818 mudas de 17 espécies, das quais apenas Schizolobium amazonicum não ocorre na área de estudo. A distância entre as mudas plantadas foi de aproximadamente 5m. As avaliações ocorreram em 2005 e 2006. Com base na sobrevivência das mudas aos 11 meses após o plantio, as espécies indicadas para o enriquecimento de clareiras são: Schizolobium amazonicum, Cedrela odorata, Jacaranda copaia, Manilkara huberi, Astronium gracile, Pouteria bilocularis, Tabebuia impetiginosa,Pseudopiptadenia suaveolens, Cordia goeldiana, Parkia gigantocarpa, Simarouba amara, Sterculia pilosa, Laetia procera, Dinizia excelsa e Schefflera morototoni. Estudos sobre a taxa de crescimento, em períodos mais longos, são necessários para confirmar a utilização dessas espécies em plantios de enriquecimento de clareiras oriundas de exploração florestal, como alternativa para aumentar a produtividade e o valor econômico das florestas naturais manejadas na Amazônia brasileira.Survival of seedlings planted in 400 gaps created by reduced impact logging in a terra firme forest in the Eastern Amazonia was evaluated. 3,818 seedlings from 17 species occurring in the study area, except for Schizolobium amazonicum (paricá, which is rare in natural forests of Paragominas region, were planted in the gaps. Spacing of planted seedlings was 5m. According to survival of seedlings during 11 months after planting, the species Schizolobium amazonicum, Cedrela odorata, Jacaranda copaia, Manilkara huberi, Astronium gracile, Pouteria bilocularis, Tabebuia impetiginosa,Pseudopiptadenia suaveolens, Cordia goeldiana, Parkia gigantocarpa, Simarouba amara, Sterculia pilosa, Laetia procera, Dinizia excelsa and Schefflera morototoni can be suggested for enriching in gaps created by reduced impact logging

  3. Antioxidant, anti-collagenase and anti-elastase activities of Phyllanthus emblica, Manilkara zapota and silymarin: an in vitro comparative study for anti-aging applications.

    Science.gov (United States)

    Pientaweeratch, Sirinya; Panapisal, Vipaporn; Tansirikongkol, Anyarporn

    2016-09-01

    Context Phyllanthus emblica L. (Euphorbiaceae) (amla), Manilkara zapota L.P. Royen (Sapotaceae) (sapota) and silymarin are reported to contain antioxidant effects. However, information on other biological activities relating to the anti-aging properties is limited. Objective To compare in vitro antioxidants, anti-collagenase (MMP-1 and MMP-2) and anti-elastase properties as well as the phenolic and flavonoid contents of amla, sapota and silymarin as potential anti-aging ingredients. Materials and methods The ethanol amla and sapota fruit extracts were prepared by three cycles of maceration with 24 h duration each. The total phenolic (TPC) and flavonoid (TFC) contents were determined. The antioxidant capacity was evaluated by DPPH and ABTS assays. The effects of MMP-1, MMP-2 and elastase inhibitions were determined by using the EnzChek® assay kits (Molecular-Probes, Eugene, OR). Results Amla exhibited the highest in TPC (362.43 ± 11.2 mg GAE/g) while silymarin showed the highest in TFC (21.04 ± 0.67 mg QE/g). Results of antioxidant activity by DPPH and ABTS methods showed that amla possessed the most potent capacity with IC50 values of 1.70 ± 0.07 and 4.45 ± 0.10 μg/mL, respectively. Highest inhibitions against MMP-1, MMP-2 and elastase were detected for sapota with IC50 values of 89.61 ± 0.96, 86.47 ± 3.04 and 35.73 ± 0.61 μg/mL, respectively. Discussion and conclusion Test extracts offered anti-aging properties in different mechanisms. Amla showed the highest phenolic content and antioxidant property with moderate anti-collagenase. Silymarin exhibited measurable flavonoid content with anti-elastase effect. Sapota showed the highest collagenase and elastase inhibitions with moderate antioxidant effect. Thus, extracts might be added as a mixture to gain the overall anti-aging effects.

  4. Riqueza de fungos anamorfos na serapilheira de Manilkara maxima, Parinari alvimii e Harleyodendron unifoliolatum na Mata Atlântica do Sul da Bahia Richness of anamorphic fungi on the litter of Manilkara maxima, Parinari alvimii and Harleyodendron unifoliolatum in the Atlantic Forest of southern Bahia

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    Dilze Maria Argôlo Magalhães

    2011-12-01

    Full Text Available A maioria dos fungos tem a função de decompor moléculas orgânicas complexas possibilitando o aporte de nutrientes para o solo pelo processo de ciclagem e fertilização. Este estudo objetiva analisar a riqueza, freqüência, constância e a similaridade entre os fungos decompositores da serapilheira de três plantas endêmicas da Mata Atlântica do Sul da Bahia e em três áreas. Folhas em decomposição foram coletadas no período de dezembro/2007 a junho/2008, lavadas, colocadas em câmaras-úmidas e incubadas na temperatura ambiente. Obteve-se uma riqueza total de 52 espécies e 39 gêneros. A riqueza obtida nas áreas foi: Parque Estadual Serra do Conduru-PESC (78,8%, Ecoparque (71,2% e Reserva Capitão (61,5%. Em relação às plantas, Harleyodendron unifoliolatum Cowan apresentou uma riqueza de 75,0%, Manilkara maxima Pennington 57,7% e Parinari alvimii Prance 42,3%. Houve similaridade fúngica entre as plantas e entre as áreas. A maioria dos fungos apresentou frequência esporádica e constância acidental. Este estudo, pioneiro na Mata Atlântica do Sul da Bahia e em relação às plantas estudadas, contribui para o conhecimento dos fungos anamorfos existentes neste bioma, riquíssimo em biodiversidade.Most fungi have the function of breaking down complex organic molecules, enabling the supply of nutrients to the soil through the process of cycling and fertilization. This paper aimed to analyze the richness, frequency, constancy and similarity among decomposing fungi on the litter of three endemic trees in three areas of the Atlantic Forest in southern Bahia. Decaying leaves were collected from December 2007 to June 2008, washed, placed in wet chambers and incubated at room temperature. Fifty-two fungal species belonging to 39 genera were found. The richness of each area was the following: Parque Estadual Serra do Conduru (78,8%, Ecoparque (71.2% and Reserva Capitão (61.5%. In relation to plants, the richness of Harleyodendron

  5. Potential production of Aspidosperma cylindrocarpon seedlings viarescue seedlings

    Directory of Open Access Journals (Sweden)

    Nathália Ferreira e Silva

    Full Text Available ABSTRACT: Translocation of rare populations is regarded as the last resort for the conservation of species whose habitat destruction is imminent. The objective of the present study was to evaluate the effect of two height classes and three leaf reduction intensities on growth and increases in height, stem diameter, survival, and new leaf production in seedlings of Aspidosperma cylindrocarpon (peroba obtained via rescue seedlings in a remnant of tropical semi deciduous forest. We recovered 240 individuals that were divided into two height classes (Class I-5 to 15cm and Class II-20 to 35cm and subjected to three leaf reduction intensities (0%, 50%, and 100%, which were then transported to a shade house with 50% light reduction. Measurements of height, stem diameter, and new leaf production were collected 8 times at 0, 15, 60, 75, 90, 105, 120, and 135 days, and survival rate was measured at day 135. The average survival rate was 82.9%; 77.5% for one Class I (5-15cm and 88.3% for Class II (20-35cm. Higher seedling growth was observed for the 0% leaf reduction treatment in both height classes. The leaves insertion were greater in the 100% cuts, with a decrease observed over time. It is advisable to restore A. cylindrocarpon seedlings in two height classes owing to the high survival rate, leaf appearance, and growth reported in the present study. The no-leaf reduction treatment (0% is the most viable alternative for the production of A. cylindrocarpon seedlings, via rescue seedlings.

  6. Indoleacetaldehyde in Cucumber Seedlings 1

    Science.gov (United States)

    Purves, William K.; Brown, Hugh M.

    1978-01-01

    The presence of indoleacetaldehyde in cucumber (Cucumis sativus L.) cotyledons was demonstrated by thin layer chromatographic RF values in three solvent systems, by the formation and hydrolysis of a bisulfite adduct, and by chemical reduction to indoleethanol and oxidation to indoleacetic acid. Bioassays indicated a minimum indoleacetaldehyde content in etiolated cotyledons of 0.7 μg per kg fresh weight. Tissue samples from all parts of both green and etiolated cucumber seedlings reduced exogenously supplied indoleacetaldehyde to indoleethanol. PMID:16660219

  7. Diversity of seedling responses to drought

    NARCIS (Netherlands)

    Slot, M.; Poorter, L.

    2007-01-01

    Drought is an important seedling mortality agent in dry and moist tropical forests, and more severe and frequent droughts are predicted in the future. The effect of drought on leaf gas exchange and seedling survival was tested in a dry-down experiment with four tree species from dry and moist forest

  8. Mycorrhizas on nursery and field seedlings of Quercus garryana.

    Science.gov (United States)

    Southworth, Darlene; Carrington, Elizabeth M; Frank, Jonathan L; Gould, Peter; Harrington, Connie A; Devine, Warren D

    2009-03-01

    Oak woodland regeneration and restoration requires that seedlings develop mycorrhizas, yet the need for this mutualistic association is often overlooked. In this study, we asked whether Quercus garryana seedlings in nursery beds acquire mycorrhizas without artificial inoculation or access to a mycorrhizal network of other ectomycorrhizal hosts. We also assessed the relationship between mycorrhizal infection and seedling growth in a nursery. Further, we compared the mycorrhizal assemblage of oak nursery seedlings to that of conifer seedlings in the nursery and to that of oak seedlings in nearby oak woodlands. Seedlings were excavated and the roots washed and examined microscopically. Mycorrhizas were identified by DNA sequences of the internal transcribed spacer region and by morphotype. On oak nursery seedlings, predominant mycorrhizas were species of Laccaria and Tuber with single occurrences of Entoloma and Peziza. In adjacent beds, seedlings of Pseudotsuga menziesii were mycorrhizal with Hysterangium and a different species of Laccaria; seedlings of Pinus monticola were mycorrhizal with Geneabea, Tarzetta, and Thelephora. Height of Q. garryana seedlings correlated with root biomass and mycorrhizal abundance. Total mycorrhizal abundance and abundance of Laccaria mycorrhizas significantly predicted seedling height in the nursery. Native oak seedlings from nearby Q. garryana woodlands were mycorrhizal with 13 fungal symbionts, none of which occurred on the nursery seedlings. These results demonstrate the value of mycorrhizas to the growth of oak seedlings. Although seedlings in nursery beds developed mycorrhizas without intentional inoculation, their mycorrhizas differed from and were less species rich than those on native seedlings.

  9. Controlled release fertilizer improves quality of container longleaf pine seedlings

    Science.gov (United States)

    R. Kasten Dumroese; Jeff Parkhurst; James P. Barnett

    2005-01-01

    In an operational trial, increasing the amount of nitrogen (N) applied to container longleaf pine seedlings by incorporating controlled release fertilizer (CRF) into the media improved seedling growth and quality. Compared with control seedlings that received 40 mg N, seedlings receiving 66 mg N through CRF supplemented with liquid fertilizer had needles that were 4 in...

  10. Cucumber Seedling Indoleacetaldehyde Oxidase 1

    Science.gov (United States)

    Bower, Peter J.; Brown, Hugh M.; Purves, William K.

    1978-01-01

    Extracts of light-grown Cucumis sativus L. seedlings catalyzed the oxidation of indole-3-acetaldehyde to indole-3-acetic acid. No added cofactors were required. Inhibitor studies indicated that the enzyme is a metalloflavoprotein. While indole-3-aldehyde, benzaldehyde, and phenylacetaldehyde partially inhibited the oxidation of indole-3-acetaldehyde, suggesting that they may serve as alternative substrates, it is proposed that indoleacetaldehyde is the major substrate in vivo. 2,4-Dichlorophenoxyacetic acid strongly inhibited the indoleacetaldehyde oxidase activity, and it is proposed that this enzyme may be subject in vivo to feedback inhibition by indole-3-acetic acid. The enzyme was activated by brief heating or by treatment with mercaptoethanol. PMID:16660220

  11. Influence of NaCl Pretreatment on the Pigment Contents of M.roxburghiana Seedlings under Low Temperature Stress%不同NaCl预处理对低温胁迫古巴牛乳树幼苗叶片色素含量的影响

    Institute of Scientific and Technical Information of China (English)

    宋志瑜; 刘育梅

    2013-01-01

    In order to learn the influence of NaCl pretreatment on the pigment of M.roxburghiana seedling in low temperature,the pigment contents in leaves were mensurated after the pretreatment of NaCl stress as well as heat shock.The results showed that the pretreatment of 6‰ NaC1 stress might distinctly protect the species from cold damage,on the condition the content of total chlorophyll,chlorophyll a or chlorophyll b was higher than that of other pretreatment,and the salinity in potted soil was 3.70‰.%对古巴牛乳树盆栽苗进行不同浓度的NaC1预处理及热激预处理,探索其对低温下古巴牛乳树[Manilkara roxburghiana (Wight) Dubard]叶片色素的影响.结果表明:6‰NaC1预处理能有效缓解古巴牛乳树幼苗叶片受低温伤害,总叶绿素、叶绿素a及叶绿素b均较高于其它处理,此时盆土的实际盐度是3.70‰.

  12. Seedling quality of common sage (Salvia officinalis L. as affected by seedling production methods

    Directory of Open Access Journals (Sweden)

    Ömer Çalişkan

    2006-09-01

    Full Text Available The study was conducted to determine the effects of four different seedling production methods (i.e., open seedbed, greenhouse seedbed, float system and modified float system on the seedling growth and quality of common sage. Sowing rates were 1 g per m2 in an open seedbed and a greenhouse seedbed system, whereas the sowing rate was one seed per cell in the float and modified float systems. Emergence period, seedling growth period, the fresh and dry weights of aerial parts of seedlings, the fresh and dry weights of roots, seedling height, root height and stem diameter were determined as agronomical observations and measurements. The greenhouse seedling method was found to be superior over the other methods

  13. Seed Mucilage Improves Seedling Emergence of a Sand Desert Shrub

    OpenAIRE

    Xuejun Yang; Baskin, Carol C.; Baskin, Jerry M.; Guangzheng Liu; Zhenying Huang

    2012-01-01

    The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed mucilage enhances seedling emergence in a low precipitation regime and under conditions of sand buria...

  14. Ostryopsis davidiana seedlings inoculated with ectomycorrhizal fungi facilitate formation of mycorrhizae on Pinus tabulaeformis seedlings.

    Science.gov (United States)

    Bai, Shu-Lan; Li, Guo-Lei; Liu, Yong; Kasten Dumroese, R; Lv, Rui-Heng

    2009-08-01

    Reforestation in China is important for reversing anthropogenic activities that degrade the environment. Pinus tabulaeformis is desired for these activities, but survival and growth of seedlings can be hampered by lack of ectomycorrhizae. When outplanted in association with Ostryopsis davidiana plants on reforestation sites, P. tabulaeformis seedlings become mycorrhizal and survival and growth are enhanced; without O. davidiana, pines often remain without mycorrhizae and performance is poorer. To better understand this relationship, we initiated an experiment using rhizoboxes that restricted root and tested the hypothesis that O. davidiana seedlings facilitated ectomycorrhizae formation on P. tabulaeformis seedlings through hyphal contact. We found that without O. davidiana seedlings, inocula of five indigenous ectomycorrhizal fungi were unable to grow and associate with P. tabulaeformis seedlings. Inocula placed alongside O. davidiana seedlings, however, resulted in enhanced growth and nutritional status of O. davidiana and P. tabulaeformis seedlings, and also altered rhizosphere pH and phosphatase activity. We speculate that these species form a common mycorrhizal network and this association enhances outplanting performance of P. tabulaeformis seedlings used for forest restoration.

  15. Effect of petroleum products on mangrove seedlings

    Digital Repository Service at National Institute of Oceanography (India)

    Jagtap, T.G.; Untawale, A.G.

    seen. General damage in both the species were burning, yellowing and wilting of the leaves associated with root damage causing retardation of growth. Extensive leaf fall in Avicennia seedlings resulted in its mortality...

  16. Virulence of Fusarium species to alfalfa seedlings

    Directory of Open Access Journals (Sweden)

    Krnjaja Vesna

    2005-01-01

    Full Text Available In in vitro conditions, virulence of 91 isolates of species Fusarium genus (F. oxysporum, F. solani, F. acuminatum, F. equiseti, F. arthrosporioides, F. prolifera- tum, F. avenaceum, F. semitectum, F. tricinctum, F. sporotrichioides and F. graminearum towards alfalfa seedlings was investigated. Isolates of investigated species originated from diseased alfalfa plants collected at four locations in Serbia based on symptoms of wilting caused by Fusarium and root rotting. Pathogenicity and virulence of investigated isolates of Fusarium spp. were determined by visual evaluation of inoculated seedlings of cultivar K28 in laboratory conditions. All isolated of investigated species had pathogenic effect on alfalfa seedlings which expressed symptoms such as necrosis of root, moist rotting and "melting of seedlings". Colour of necrotic root tissue varied from light brown, brown lipstick red to explicit black, depending on the Fusarium species. Strong virulence was established in 48 isolates, medium virulence in 31 and weak virulence in 12 isolates.

  17. Virulence of Fusarium species to alfalfa seedlings

    Directory of Open Access Journals (Sweden)

    Krnjaja Vesna

    2005-01-01

    Full Text Available In in vitro conditions, virulence of 91 isolates of species Fusarium genus (F. oxysporum, F. solani, F. acuminatum, F. equiseti, F. arthrosporioides, F. proliferatum, F. avenaceum, F. semitectum, F. tricinctum, F. sporotrichioides and F. graminearum towards alfalfa seedlings was investigated. Isolates of investigated species originated from diseased alfalfa plants collected on four locations in Serbia based on symptoms of wilting caused by fusarium and root rotting. Pathogenicity and virulence of investigated isolates of Fusarium spp. were determined by visual evaluation of inoculated seedlings of cultivars K28 in laboratory conditions. All isolated of investigated species had pathogenic effect on alfalfa seedlings, which expressed symptoms such as necrosis of root, moist rotting and "melting of seedlings". Colour of necrotic root tissue varied from light brown, brown, lipstick red to explicit black, depending on the Fusarium species. Strong virulence was established in 48 isolates, medium virulence in 31 and weak virulence in 12 isolates.

  18. Morphoanatomy of Serjania communis Cambess. seedling (Sapindaceae

    Directory of Open Access Journals (Sweden)

    Willian Adriano Lira Lopes

    2015-07-01

    Full Text Available Serjania communis Cambess. (Sapindaceae is a plant with climbing habit and occurs relatively often in Paraná State, Brazil. The fruits were collected at the 'Parque dos Pioneiros' a remnant of subtropical forest in Maringá, Paraná State, Brazil. The seedlings obtained in the greenhouse were described according to traditional techniques in plant morphology. Seedlings were embedded in historesin and sectioned in rotation microtome. The fruit is the samaroid type, the seeds have about 3 mm in length and brown color. Seedlings are epigeal phanerocotylar. The seedlings have a hairy hypocotyl, foliaceous cotyledons, reduced epicotyl, and two opposite eophylls. The root is diarch, the hypocotyl shows root-stem transition structure, stem epicotyl, and dorsiventral and hypostomatous cotyledons and eophylls. 'Tirodendros' with 45 days of age do not develop cambial variant.

  19. Morphoanatomy of Serjania communis Cambess. seedling (Sapindaceae)

    OpenAIRE

    2015-01-01

    Serjania communis Cambess. (Sapindaceae) is a plant with climbing habit and occurs relatively often in Paraná State, Brazil. The fruits were collected at the 'Parque dos Pioneiros' a remnant of subtropical forest in Maringá, Paraná State, Brazil. The seedlings obtained in the greenhouse were described according to traditional techniques in plant morphology. Seedlings were embedded in historesin and sectioned in rotation microtome. The fruit is the samaroid type, the seeds have about 3 mm in l...

  20. Influence of plant-parasitic nematodes on longleaf pine seedlings.

    Science.gov (United States)

    Ruehle, J L

    1973-01-01

    Seedlings of longleaf pine (Pinus palustris) were grown in 20-cm pots for 5 to 7 months in the greenhouse following inoculation with a high or low level of one of seven species of plant-parasitic nematodes. Belonolaimus longicaudatus and Helicotylenchus dihystera had no effect on seedling growth. High inoculum densities of Hoplolaimus galeatus and Tylenchorhynchus claytoni caused a significant reduction of fresh weight of seedling roots. Root and top weights of seedlings grown in soil infested with Meloidodera floridensis or Pratylenchus brachyurus were significantly less than those of seedlings in noninfested soil. Root growth of seedlings was stimulated by the higher inoculum density of Scutellonema brachyurum.

  1. Simulated drought influences oxidative stress in Zea mays seedlings ...

    African Journals Online (AJOL)

    Simulated drought influences oxidative stress in Zea mays seedlings. ... Bayero Journal of Pure and Applied Sciences. Journal Home · ABOUT ... Seedlings were grown for 8 weeks in nursery bags filled with sandy-loam soil in two categories.

  2. The fungi causin damping-off of carrot seedlings

    Directory of Open Access Journals (Sweden)

    Bogdan Nowicki

    2013-12-01

    Full Text Available When 136 samples of dying carrot seedlings from several fields were analyzed Alternaria rudicina proved to be the most common seedling pathogen (41%, followed by some Fusarium species (27%, mostly F. avenaceum.The less common seedling pathogens were Pythium spp. (13%, Phoma spp.(2,5% and Botrytis cinerea (1,4%. Some other fungi (Bipolaris sorokiniana, Sclerotinia sclerotiorum, Stemphylium botryosym and Ulocladium consortiale were found in less than 1% of seedlings examined.

  3. Containers of Attalea funifera fibers to produce eucalyptus seedlings

    Directory of Open Access Journals (Sweden)

    Andrea Vita Reis Mendonça

    2016-09-01

    Full Text Available The aim of this study was to assess the technical feasibility of using biodegradable containers made of fiber waste of Attalea funifera Martius to produce seedling of Eucalyptus camaldulensis Dehnh. The work was carried out in three stages: manufacture of piassava fiber containers, seedling production and field simulation. The experiment of seedling production was in completely randomized design, with two treatments (polyethylene tube and biodegradable container and 10 repetitions, with 64 seedlings per repetition. After 93 days, seedlings were evaluated based on quality variables. The simuation of initial growth of seedlings in the field consisted in planting seedlings in containers of 11L, in completely randomized design, with three treatments: seedlings produced in polyethylene tubes; seedlings produced in biodegradable containers, without removal of the container during planting; and seedlings produced in biodegradable containers, with removal of the container at planting, with ten repetitions, with one seedling by repetition. The biodegradable container withstood the production cycle and resulted in seedlings within acceptable standards quality. The use of biodegradable container, made of palm fibers, waived the removal of this vessel in the final planting.

  4. Containers of Attalea funifera fibers to produce eucalyptus seedlings

    Directory of Open Access Journals (Sweden)

    Andrea Vita Reis Mendonça

    2016-09-01

    Full Text Available The aim of this study was to assess the technical feasibility of using biodegradable containers made of fiber waste of Attalea funifera Martius to produce seedling of Eucalyptus camaldulensis Dehnh. The work was carried out in three stages: manufacture of piassava fiber containers, seedling production and field simulation. The experiment of seedling production was in completely randomized design, with two treatments (polyethylene tube and biodegradable container and 10 repetitions, with 64 seedlings per repetition. After 93 days, seedlings were evaluated based on quality variables. The simuation of initial growth of seedlings in the field consisted in planting seedlings in containers of 11L, in completely randomized design, with three treatments: seedlings produced in polyethylene tubes; seedlings produced in biodegradable containers, without removal of the container during planting; and seedlings produced in biodegradable containers, with removal of the container at planting, with ten repetitions, with one seedling by repetition. The biodegradable container withstood the production cycle and resulted in seedlings within acceptable standards quality. The use of biodegradable container, made of palm fibers, waived the removal of this vessel in the final planting.

  5. [Influence of seedling assortment on Panax notoginseng growth and yield].

    Science.gov (United States)

    Cui, X; Wang, C; Chen, Z

    1998-02-01

    Making Panax notoginseng seedling assortment according to seedling size before transplanting, the result shows that the influence is better, the yield of root tuber and fruit is higher. Culturing good seedling is the fundamental measure to increase yield of P. notoginseng.

  6. Seed mucilage improves seedling emergence of a sand desert shrub.

    Directory of Open Access Journals (Sweden)

    Xuejun Yang

    Full Text Available The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed mucilage enhances seedling emergence in a low precipitation regime and under conditions of sand burial. In a greenhouse experiment, two types of Artemisia sphaerocephala achenes (intact and demucilaged were exposed to different combinations of burial depth (0, 5, 10, 20, 40 and 60 mm and irrigation regimes (low, medium and high, which simulated the precipitation amount and frequency in May, June and July in the natural habitat, respectively. Seedling emergence increased with increasing irrigation. It was highest at 5 mm sand burial depth and ceased at burial depths greater than 20 mm in all irrigation regimes. Mucilage significantly enhanced seedling emergence at 0, 5 and 10 mm burial depths in low irrigation, at 0 and 5 mm burial depths in medium irrigation and at 0 and 10 mm burial depths in high irrigation. Seed mucilage also reduced seedling mortality at the shallow sand burial depths. Moreover, mucilage significantly affected seedling emergence time and quiescence and dormancy percentages. Our findings suggest that seed mucilage plays an ecologically important role in successful seedling establishment of A. sphaerocephala by improving seedling emergence and reducing seedling mortality in stressful habitats of the sandy desert environment.

  7. Characterization of rhizobacteria associated with weed seedlings.

    Science.gov (United States)

    Kremer, R J; Begonia, M F; Stanley, L; Lanham, E T

    1990-06-01

    Rhizobacteria were isolated from seedlings of seven economically important weeds and characterized for potential phytopathogenicity, effects on seedling growth, and antibiosis to assess the possibility of developing deleterious rhizobacteria as biological control agents. The abundance and composition of rhizobacteria varied among the different weed species. For example, fluorescent pseudomonads represented from 11 to 42% of the total rhizobacterial populations from jimsonweed and lambsquarters, respectively. Other bacteria frequently isolated were nonfluorescent pseudomonads, Erwinia herbicola, Alcaligenes spp., and Flavobacterium spp. Only 18% of all isolates were potentially phytopathogenic, based on an Escherichia coli indicator bioassay. However, the proportion of isolates that inhibited growth in seedling assays ranged from 35 to 65% depending on the weed host. Antibiosis was most prevalent among isolates of fluorescent Pseudomonas spp., the activity of which was due to siderophore production in over 75% of these isolates. Overall, rhizobacterial isolates exhibited a complex array of properties that were inconsistent with accepted definitions for plant growth-promoting and deleterious rhizobacteria. It is suggested that for development of effective biological control agents for weed control, deleterious rhizobacteria must be screened directly on host seedlings and must possess several properties including high colonizing ability, specific phytotoxin production, and resistance or tolerance to antibiotics produced by other rhizosphere microorganisms, and they must either synthesize or utilize other bacterial siderophores.

  8. Water management in hardening Maytenus ilicifolia (Schrad. Planch. seedlings

    Directory of Open Access Journals (Sweden)

    João Alexandre Lopes Dranski

    2017-02-01

    Full Text Available This study evaluated the effects of seedling height and irrigation management on M. ilicilofia seedlings. The experiment used a completely randomized design in a 2 x 3 factorial arrangement. Seedlings of two height classes (greater than or less than 18.0 cm were subjected to three irrigation regimes (daily irrigation, irrigation every other day, and gradual reduction of irrigation. After eight weeks, the morphophysiological and performance attributes of the seedlings were quantified. Gradual reduction of irrigation promoted the highest rate of net carbon assimilation. Irrigating every other day resulted in greater secondary growth rate, biomass accumulation in the shoot and root tissues, and lower electrolyte leakage rate. After planting, these treatments maintained higher leaf relative water content (RWC. RWC in seedlings smaller than 18 cm was significantly higher until the third week after planting. Therefore, larger seedlings submitted to hardening by gradually reducing irrigation improves seedling quality.

  9. Postfire seedling dynamics and performance in Pinus halepensis Mill. populations

    Science.gov (United States)

    Daskalakou, Evangelia N.; Thanos, Costas A.

    2010-09-01

    Postfire dynamics of Aleppo pine seedling density, survival and growth were assessed in five burned forests of Attica, Greece (Stamata, Villia, Avlona, Kapandriti and Agios Stefanos) through the establishment of permanent experimental plots. All emerging seedlings were tagged and their survival and growth monitored at regular intervals. Seedling density dynamics show an initial, steep increase (to maximum values 2.9-4.6 seedlings m -2) followed by a gradual decrease that levels off at the second and third postfire year (1.3-3.0 seedlings m -2); similarly, postfire seedling survival more or less stabilised at 30-50%, 2-3 years after fire. On the basis of density and mortality trends as well as relevant bibliographic data, it is predicted that very dense, mature forests (10.000 trees ha -1 or more) will be reinstated within 15-20 years. During the first 5-7 postfire years, seedling/sapling annual height followed linear trends with various yearly rates, ranging mostly between 8 and 15 cm (and 27-30 cm in two exceptional, fast growing cases). Within an individual growth season, seedling height dynamics were found to follow sigmoid curves with growth increment peaks in mid-spring. The time (on a monthly basis) of seedling emergence did not affect seedling growth or survival. On the other hand, for the first time under natural conditions, it has been shown that cotyledon number per seedling, an indirect measure of both seed size and initial photosynthetic capacity, significantly affected seedling survival but not growth. Seedlings bearing a higher number of cotyledons, presumably derived from larger seeds, showed greater survival at the end of the first postfire year than seedlings with fewer cotyledons. A postfire selective pressure, favouring large seed size, is postulated to counteract with a contrasting one, which favours small seed size, expressed during fire-free conditions.

  10. On the biomechanics of seedling anchorage

    Science.gov (United States)

    Crouzy, Benoît; Edmaier, Katharina; Perona, Paolo

    2014-05-01

    We propose a minimal model for the response of vegetation to pullout constraints at early development stage. We try to capture both the average mechanical properties of the root system and the stochastic component of the uprooting process of seedlings. We identify a minimal set of relevant physical components in the purpose of quantifying the uprooting process: length of the root fibres, elastic response of the fibres and adhesion between the roots and the soil matrix. We present for validation a dataset extracted from Edmaier et al. (under revision), accounting for 98 uprooting experiments using Avena sativa L. seedlings (common oat), growing in non-cohesive sediment under controlled conditions. The corresponding root system has a very simple architecture, with three root fibres of different lengths. The response of the system to the constraint is however complex: the stress-strain signal presents sudden jumps followed by partial elastic recoveries. The analysis of the jumps and partial recoveries gives an insight into the resilience of the system. The anchorage of less mature seedlings rapidly collapses after the peak force has been reached, while more mature seedlings usually recover from partial failures. We explore this crossover with our validation dataset. The type of seedlings we study has been used in flume experiments investigating the feedbacks between the vegetation and the river morphodynamics (see for example Perona et al. (2012)). An understanding of the characteristics of the uprooting curve (maximal uprooting force and total uprooting work) of such vegetation reveals the ability of seedlings to withstand environmental constraints in terms of duration or intensity (see Edmaier et al., under revision), and is therefore helpful for planning future experiments. REFERENCES - P. Perona, P. Molnar, B. Crouzy, E. Perucca, Z. Jiang, S. McLelland, D. Wüthrich, K. Edmaier, R. Francis, C. Camporeale, et al., Biomass selection by floods and related timescales

  11. Multiple amine oxidases in cucumber seedlings.

    Science.gov (United States)

    Percival, F W; Purves, W K

    1974-10-01

    Cell-free extracts of cucumber (Cucumis sativus L. cv. National Pickling) seedlings were found to have amine oxidase activity when assayed with tryptamine as a substrate. Studies of the effect of lowered pH on the extract indicated that this activity was heterogeneous, and three amine oxidases could be separated by ion exchange chromatography. The partially purified enzymes were tested for their activities with several substrates and for their sensitivities to various amine oxidase inhibitors. One of the enzymes may be a monoamine oxidase, although it is inhibited by some diamine oxidase inhibitors. The other two enzymes have properties more characteristic of the diamine oxidases. The possible relationship of the amine oxidases to indoleacetic acid biosynthesis in cucumber seedlings is discussed.

  12. Arborescent palm seed morphology and seedling distribution

    OpenAIRE

    Rodolfo Salm

    2005-01-01

    This study examines how the seed morphology of two large arborescent palms, Attalea maripa (Aubl.) Mart. and Astrocaryum aculeatum G. Mey, may affect their seed shadow in a seasonally dry Amazonian forest. In addition to being smaller and produced in larger numbers than those of A. aculeatum, A. maripa seeds also presented a substantially lower amount of nutritional reserves available for the embryo. However, A. maripa seedlings were found in much higher numbers than those of A. aculeatum. Th...

  13. Fungi causing dying out of heather seedlings

    Directory of Open Access Journals (Sweden)

    Maria Kowalik

    2012-12-01

    Full Text Available The aim of the study was to determine the fungi causing dying out of one-yearold heather seedlings. Observations were carried out on: 'Amethyst', 'Annemarie', 'Colette', 'Perestroika' and 'Reini'. The shoots revealing necrotic symptoms were plated on PDA medium. 25 species of fungi were isolated. Among them Pestalotia sydowiana, Alternaria alternata, Cylindrocarpon destructans, Leptosphaeria coniothyrium and Epicoccum purpurascens were dominant, while Mammaria echinobotryoides, Phoma leveillei, Kaissleriella subalpina, Botrytis cinerea and Phytophthora cinnamomi occurred less frequently.

  14. Fungi causing dying out of heather seedlings

    OpenAIRE

    Maria Kowalik; Agnieszka Wandzel

    2012-01-01

    The aim of the study was to determine the fungi causing dying out of one-yearold heather seedlings. Observations were carried out on: 'Amethyst', 'Annemarie', 'Colette', 'Perestroika' and 'Reini'. The shoots revealing necrotic symptoms were plated on PDA medium. 25 species of fungi were isolated. Among them Pestalotia sydowiana, Alternaria alternata, Cylindrocarpon destructans, Leptosphaeria coniothyrium and Epicoccum purpurascens were dominant, while Mammaria echinobotryoides, Phoma leveille...

  15. Pathogenicity of P. terrestris on Maize Seedlings

    Directory of Open Access Journals (Sweden)

    Jelena Lević

    2012-01-01

    Full Text Available Pathogenicity of P. terrestris was determined by the Knop’s medium slants method intest tubes. Isolates originated from the roots of maize (Zea mays L., barley (Hordeum vulgareL., Johnson grass (Sorghum halepense Pers., sorghum (Sorghum bicolour (L. Moench., garlic(Allium sativum L., onion (Allium cepa L., barnyard millet (Echinochloa crus-galli (L. P.Beauv.and green foxtail (Setaria viridis (L. P.B.. A fragment of a fungal colony, cultivated on PDA,was placed on the bottom of Knop’s medium slant in each test tube and then steriliseda maize seed was placed 2 cm away from the inoculum. After 21-day inoculation of seeds,the intensity of the development of symptoms on maize seedlings was estimated. The reddishor dark pigment on the root, mesocotyl and/or coleoptyl of seedlings was an indicatorfor the infection by the fungus under in vitro conditions. Based on the pathogenicity test,the isolates were classified into the following three groups: slightly (3 isolates, moderately(6 isolates and very pathogenic (6 isolates to maize seedlings. The obtained results showthat P. terrestris, originating from different hosts, can be a maize pathogen. These resultscan explain the high frequency and high incidence of this fungus on maize roots in Serbia.

  16. Nutrient partitioning and seedling development in the genus Leucaena

    Energy Technology Data Exchange (ETDEWEB)

    Dovel, R.L.

    1987-01-01

    Slow establishment of the genus Leucaena from seed has been attributed to law seedling vigor and late nodulation. Observation of early seedling growth indicated that partitioning of a large proportion of resources to the root of young Leucaena seedlings could account, in part, for the slow initial shoot growth observed in this genus. Therefore, a series of experiments were conducted to examine the partitioning of stored seed reserves, photosynthate, and nitrogen in developing Leucaena seedlings. The effects of nodulation and nitrogen fertilization on partitioning of nutrients in the seedling were also examined. Seed reserves were initially used for radicle growth in dark grown seedlings; however, partitioning soon shifted to the hypocotyl. By four days after imbibition, hypocotyl weight exceeded radicle weight in both species tested (L. leucocephala and L. retusa), at all temperatures above 20/sup 0/C. Two experiments were conducted examining the carbon partitioning of L. leucocephala cultivar K-8 using /sup 14/CO/sub 2/ pulse labeling techniques.

  17. Propagation of Cucumber Seedlings in Different Organic and Inorganic Media

    Directory of Open Access Journals (Sweden)

    H. Cinkilİc

    2008-05-01

    Full Text Available The objective of this study is to investigate the possibility of using grape marc and cinder an alternative media to peat for cucumber propagation and find out the results.In the study;normal grape marc, normal grape marc+25% süper coarse perlite, ground grape marc+25% süper coarse perlite, cinder+25% süper coarse perlite, peat+25% süper coarse perlite and peat were used, the best results were obtained from grape marc + 25% super coarse perlite in stem diameter, number of true leaves, weight of seedling, width of seedling, length of leaves and width of leaves; from peat + 25% super coarse perlite in length of seedling, length of seedling with root, weight of root, weight of seedling with root and length of root. The cinder which is the residue of burned coal, gave the worst results in all seedling properties.

  18. Longleaf pine bud development: influence of seedling nutrition

    Science.gov (United States)

    J. P. Barnett; D. P. Jackson; R. K. Dumroese

    2010-01-01

    A subset of seedlings from a larger study (Jackson and others 2006, 2007) were selected and evaluated for two growing seasons to relate bud development, and root-collar diameter (RCD), and height growth with three nursery fertilization rates. We chose seedlings in the 0.5 (lowest), 2.0 (mid-range), and 4.0 (highest) mg of nitrogen per seedling treatments. Buds moved...

  19. Containers of Attalea funifera fibers to produce eucalyptus seedlings

    OpenAIRE

    Andrea Vita Reis Mendonça; Lucas Gonçalves Ribeiro; José Roque Azevedo Assunção; Teresa Aparecida Soares de Freitas; Josival Santos Souza

    2016-01-01

    The aim of this study was to assess the technical feasibility of using biodegradable containers made of fiber waste of Attalea funifera Martius to produce seedling of Eucalyptus camaldulensis Dehnh. The work was carried out in three stages: manufacture of piassava fiber containers, seedling production and field simulation. The experiment of seedling production was in completely randomized design, with two treatments (polyethylene tube and biodegradable container) and 10 repetitions, with 64 s...

  20. Habitat-related variation in seedling recruitment of Gentiana pannonica

    Science.gov (United States)

    Ekrtová, Ester; Košnar, Jan

    2012-11-01

    Differences in seedling recruitment of Gentiana pannonica were investigated between the primary (relict) and the secondary (semi-natural) forest-free habitats of the Bohemian Forest (870-1200 m a.s.l.) and of the Alps (1045-1935 m a.s.l.) to understand the factors promoting the seedling recruitment of G. pannonica and their importance for species distribution, population structure, and conservation. In the communities with adult plants of G. pannonica, we recorded environmental variables (the slope, the altitude, and the covers of bare ground, litter, and rocks), estimated parameters of the vegetation (the covers of herbs, bryophytes, and dwarf shrubs), and counted the seedlings of G. pannonica. In a field experiment, we investigated seedling survival under different soil moisture regimes. We also observed seasonal dynamics of seedling recruitment in permanent plots over the course of three years. In the primary habitats of both regions, G. pannonica grew in a relatively wide range of communities, and its seedlings occurred in each area. In the secondary habitats of the Bohemian Forest, a very low frequency of the seedlings was recorded. The number of seedlings increased with the covers of the moss layer and of bare soil and decreased with the cover of the herb layer, especially of graminoids. The seedling mortality was significantly lower in the plots with higher soil moistures, and the emergence of new-born seedlings was concentrated in the spring season, when the soil received a high water supply due to melting of snow. For the successful generative reproduction of G. pannonica, our findings highlight the critical importance of the microsites with low levels of competition and of sufficient soil moisture G. pannonica. It seems that because of the long-term lack of grazing disturbances, the structures of the secondary habitats of G. pannonica in the Bohemian Forest have become unfavourable for seedling establishment and generative reproduction of this threatened

  1. Quality of tomato seedling in application bioproducts

    OpenAIRE

    BOTEVA, Hriska

    2014-01-01

    The study was performed during the period 2009 - 2011 in the “Maritsa” Vegetable Crops Research Institute, Plovdiv. The effect of organic products Baikal EM – 1У, Bioglobin and Biolan on the quality of seedlings from tomato, variety Yana was studied in unheated glasshouses ro-ON type. Plants were grown on two substrates: peat-perlite substrate and substrate with Lumbrikal. The post-effect of the applied bioproducts on the plant productivity was studied in field conditions. Tomato seeds from Y...

  2. Radiation effects on Brassica seeds and seedlings

    Science.gov (United States)

    Deoli, Naresh; Hasenstein, Karl H.

    2016-07-01

    Space radiation consists of high energy charged particles and affects biological systems, but because of its stochastic, non-directional nature is difficult to replicate on Earth. Radiation damages biological systems acutely at high doses or cumulatively at low doses through progressive changes in DNA organization. These damages lead to death or cause of mutations. While radiation biology typically focuses on mammalian or human systems, little is known as to how radiation affects plants. In addition, energetic ion beams are widely used to generate new mutants in plants considering their high-LET (Linear Energy Transfer) as compared to gamma rays and X-rays. Understanding the effect of ionizing radiation on plant provides a basis for studying effects of radiation on biological systems and will help mitigate (space) radiation damage in plants. We exposed dry and imbibed Brassica rapa seeds and seedling roots to proton beams of varying qualities and compared the theoretical penetration range of different energy levels with observable growth response. We used 1, 2 and 3 MeV protons in air at the varying fluences to investigate the effect of direct irradiation on the seeds (1012 - 1015 ions/cm2) and seedlings (1013 ions/cm2). The range of protons in the tissue was calculated using Monte-Carlo based SRIM (Stopping and Range of Ions in Matter) software. The simulation and biological results indicate that ions did not penetrate the tissue of dry or hydrated seeds at all used ion energies. Therefore the entire energy was transferred to the treated tissue. Irradiated seeds were germinated vertically under dim light and roots growth was observed for two days after imbibition. The LD50 of the germination was about 2×1014 ions/cm2 and about 5×1014 ions/cm2 for imbibed and dry seeds, respectively. Since seedlings are most sensitive to gravity, the change in gravitropic behavior is a convenient means to assess radiation damage on physiological responses other than direct tissue

  3. Evaluation of Promalin to promote growth of young mangosteen seedlings

    Science.gov (United States)

    A major impediment to the development of a mangosteen (Garcinia mangostana L.) industry is the long pre-bearing stage that seedlings take to produce fruits. A field study was conducted to determine the effect of Promalin on the growth of mangosteen seedlings. Promalin was applied as a foliar spray...

  4. Fusarium resistance in Gladiolus: selection in seedling populations

    NARCIS (Netherlands)

    Straathof, Th.P.; Jansen, J.; Roebroeck, E.J.A.; Löffler, H.J.M.

    1997-01-01

    A test to select Fusarium resistant seedlings of Gladiolus is described. Seedlings of 37 populations, obtained from an incomplete diallel between eight parents with different levels of Fusarium resistance, were used. Significant differences in Fusarium infection between and within populations were d

  5. Coumarin pretreatment alleviates salinity stress in wheat seedlings.

    Science.gov (United States)

    Saleh, Ahmed Mahmoud; Madany, M M Y

    2015-03-01

    The potentiality of COU to improve plant tolerance to salinity was investigated. Wheat grains were primed with COU (50 ppm) and then grown under different levels of NaCl (50, 100, 150 mM) for two weeks. COU pretreatment improved the growth of wheat seedling under salinity, relative to COU-untreated seedlings, due to the accumulation of osmolytes such as soluble sugars and proline. Moreover, COU treatment significantly improved K(+)/Na(+) ratio in the shoots of both salt stressed and un-stressed seedlings. However, in the roots, this ratio increased only under non-salinity. In consistent with phenylalanine ammonia lyase (PAL), phenolics and flavonoids were accumulated in COU-pretreated seedlings under the higher doses of salinity, relative to COU-untreated seedlings. COU primed seedlings showed higher content of the coumarin derivative, scopoletin, and salicylic, chlorogenic, syringic, vanillic, gallic and ferulic acids, under both salinity and non-salinity conditions. Salinity stress significantly improved the activity of peroxidase (POD) in COU-pretreated seedlings. However, the effect of COU on the total antioxidant capacity (TAC) was only obtained at the highest dose of NaCl (150 mM). The present results suggest that COU pretreatment could alleviate the adverse effect of salinity on the growth of wheat seedlings through enhancing, at least partly, the osmoregulation process and antioxidant defense system.

  6. Photoreceptive sites in the photocontrol of oat seedling growth

    Directory of Open Access Journals (Sweden)

    Kazimierz Madela

    2014-01-01

    Full Text Available The influence of red light on the growth of coleoptiles and mesocotyles of etiolated and pre-irradiated oat seedlings was investigated. Red light (15 min. applied on whole seedlings stimulated the elongation of coleoptiles and inhibited the growth of mesocotyles both in etiolated and in pre-irradiated plants. Irradiation with red light (2 min of various 2-mm-long regions of etiolated and pre-irradiated oat seedlings was carried out in order to locate their light reception regions. On the basis of growth reactions after such treatment it was found that in completely etiolated seedlings the light reception sites involved in the stimulation of coleoptile elongation and inhibition of mesocotyle growth lie directly above and below the seedling node, whereas in pre-irradiated seedlings, in the top of the seedling. These results point to the existence of different growth photoregulation systems in etiolated and pre-irradiated oat seedlings. The role of phytochrome in these phenomena is discussed.

  7. Control damage by seedling debarking weevil. Technical note No. 271

    Energy Technology Data Exchange (ETDEWEB)

    Eidt, D.C.; Weaver, C.A.A.

    1993-01-01

    Technical note describing a method of controlling the damage to seedlings by the seedling debarking weevil by using nematodes. Information is given on the damage involved, the nematodes to be used, treatment methods, planting procedures, benefits and costs, and results of earlier trials.

  8. Provenances and fertilizer on early growth cedar seedlings

    Directory of Open Access Journals (Sweden)

    Marcio Carlos Navroski

    2016-03-01

    Full Text Available The aim of the study was to evaluate the initial development of different provenances and the influence of base fertilizer and coverage on growth of Cedrela fissilis seedlings. Provenances of seeds were collected in Lapa, PR, Fernandes Pinheiro, PR and Itaara, RS. After germination, the seedlings were transplanted to plastic bags of 500 cm³, filled with commercial substrate. Total height (h, stem diameter (sd, and ratio h/sd seedlings were measured after 150 days of transplanting. Seedlings of Fernandes Pinheiro received basic fertilization after transplantation (0, 2, 4, 6 and 8 g dm-3  Osmocote® and cover (3 and 6 g L-1, respectively, of Peter’s® and urea. The provenance and doses of controlled-release fertilizer influenced early development of Cedrela fissilis seedlings. Itaara provenance showed better seedlings growth. Cedar seedlings showed good growth when incorporated into the substrate 5 g dm-3 Osmocote® and, in addition, applied in topdressing 3 g L-1 of Peter’s®. Urea topdressing is rarely recommended for cedar seedlings.

  9. Evolutionary history and distance dependence control survival of dipterocarp seedlings.

    Science.gov (United States)

    Bagchi, Robert; Press, Malcolm C; Scholes, Julie D

    2010-01-01

    One important hypothesis to explain tree-species coexistence in tropical forests suggests that increased attack by natural enemies near conspecific trees gives locally rare species a competitive advantage. Host ranges of natural enemies generally encompass several closely related plant taxa suggesting that seedlings should also do poorly around adults of closely related species. We investigated the effects of adult Parashorea malaanonan on seedling survival in a Bornean rain forest. Survival of P. malaanonan seedlings was highest at intermediate distances from parent trees while heterospecific seedlings were unaffected by distance. Leaf herbivores did not drive this relationship. Survival of seedlings was lowest for P. malaanonan, and increased with phylogenetic dissimilarity from this species, suggesting that survival of close relatives of common species is reduced. This study suggests that distance dependence contributes to species coexistence and highlights the need for further investigation into the role of shared plant enemies in community dynamics.

  10. Analysis on Factors Affecting Seedling Establishment in Rice

    Directory of Open Access Journals (Sweden)

    Ju LUO

    2007-03-01

    Full Text Available Elongations of coleoptile and mesocotyl are related directly to rice seedling establishment in soil and height of plant is related to lodging in rice production. Twelve typical rice cultivars with different lengths of coleoptile and mesocotyl (long, medium and short were selected by screening the lengths of coleoptile and mesocotyl in 1500 accessions. The seedling establishments of these typical cultivars were compared under the combinations of different sowing depths and flooding durations, and two semi-dwarf varieties (G140, Zhong 96–21 with good seedling establishments and optimum mesocotyl lengths were found. The length of mesocotyl was completely fitted negative binomial distribution and the length of coleoptile was nearly fitted lognormal distribution. Analysis of the relationships among mesocotyl, coleoptile, seeding depth, flooding duration, and their interactions to seedling establishment percentage showed that there existed significant relations among mesocotyl, coleoptile, mesocotyl × coleoptile, seeding depth, flooding duration and mesocotyl × sowing depth in the experiment for seedling establishment.

  11. Analysis on Factors Affecting Seedling Establishment in Rice

    Institute of Scientific and Technical Information of China (English)

    LUO Ju; TANG Shao-qing; HU Pei-song; Aleman LOUIS; JIAO Gui-ai; TANG Jian

    2007-01-01

    Elongations of coleoptile and mesocotyl are related directly to rice seedling establishment in soil and height of plant is related to lodging in rice production. Twelve typical rice cultivars with different lengths of coleoptile and mesocotyl (long, medium and short) were selected by screening the lengths of coleoptile and mesocotyl in 1500 accessions. The seedling establishments of these typical cultivars were compared under the combinations of different sowing depths and flooding durations, and two semi-dwarf varieties (G140, Zhong 96-21) with good seedling establishments and optimum mesocotyl lengths were found. The length of mesocotyl was completely fitted negative binomial distribution and the length of coleoptile was nearly fitted Iognormal distribution.Analysis of the relationships among mesocotyl, coleoptile, seeding depth, flooding duration, and their interactions to seedling establishment percentage showed that there existed significant relations among mesocotyl, coleoptile, mesocotyl × coleoptile,seeding depth, flooding duration and mesocotyl × sowing depth in the experiment for seedling establishment.

  12. Effects of graphene on seed germination and seedling growth

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming; Gao, Bin, E-mail: bg55@ufl.edu [University of Florida, Department of Agricultural and Biological Engineering (United States); Chen, Jianjun [University of Florida, Department of Environmental Horticulture and Mid-Florida Research & Education Center (United States); Li, Yuncong [University of Florida, Soil and Water Science Department Tropical Research & Education Center (United States)

    2015-02-15

    The environmental impact of graphene has recently attracted great attention. In this work, we show that graphene at a low concentration affected tomato seed germination and seedling growth. Graphene-treated seeds germinated much faster than control seeds. Analytical results indicated that graphene penetrated seed husks. The penetration might break the husks to facilitate water uptake, resulting in faster germination and higher germination rates. At the stage of seedling growth, graphene was also able to penetrate root tip cells. Seedlings germinated from graphene-treated seeds had slightly lower biomass accumulation than the control, but exhibited significantly longer stems and roots than the control, which suggests that graphene, in contrast with other nanoparticles, had different effects on seedling growth. Taken together, our results imply that graphene played complicated roles in affecting the initial stage of seed germination and subsequent seedling growth.

  13. Screening cotton genotypes for seedling drought tolerance

    Directory of Open Access Journals (Sweden)

    Penna Julio C. Viglioni

    1998-01-01

    Full Text Available The objectives of this study were to adapt a screening method previously used to assess seedling drought tolerance in cereals for use in cotton (Gossypium hirsutum L. and to identify tolerant accessions among a wide range of genotypes. Ninety genotypes were screened in seven growth chamber experiments. Fifteen-day-old seedlings were subjected to four 4-day drought cycles, and plant survival was evaluated after each cycle. Three cycles are probably the minimum required in cotton work. Significant differences (at the 0.05 level or lower among entries were obtained in four of the seven experiments. A "confirmation test" with entries previously evaluated as "tolerant" (high survival and "susceptible" (low survival was run. A number of entries duplicated their earlier performance, but others did not, which indicates the need to reevaluate selections. Germplasms considered tolerant included: `IAC-13-1', `IAC-RM4-SM5', `Minas Sertaneja', `Acala 1517E-1' and `4521'. In general, the technique is simple, though time-consuming, with practical value for screening a large number of genotypes. Results from the screening tests generally agreed with field information. The screening procedure is suitable to select tolerant accessions from among a large number of entries in germplasm collections as a preliminary step in breeding for drought tolerance. This research also demonstrated the need to characterize the internal lack of uniformity in growth chambers to allow for adequate designs of experiments.

  14. Effects of "short" photoperiods on seedling growth of Pinus brutia.

    Science.gov (United States)

    Iakovoglou, V; Radoglou, K; Kostopoulou, P; Dini-Papanastasi, O

    2012-03-01

    This study investigated how nurseries could benefit by inducing "short" photoperiods as low as 4 hr to produce "better" seedlings characterized by more vigorous roots; a substantial feature to overcome transplanting stress. The carryover effect of the photoperiod was also investigated on seedlings that grew for 30 days more underthe consistent 14 hr photoperiod. Seedlings of Pinus brutia were subjected to 4, 6, 8 and 14 hr photoperiod for 3 week. Fifteen seedlings were used to evaluate the leaf area, the root and shoot dry weight and their ratio. Six and sixteen seedlings were used to evaluate the shoot electrolyte leakage and the root growth potential, respectively. Based on the results, the 6 and 8 hr photoperiod indicated greater root allocation (4.8 and 4.9 mg, respectively) and chlorophyll content (3.7 and 4.4, respectively). They also indicated greater leaf area values (3.3 and 3.5 cm2, respectively) along with the 14 hr (3.4 cm2). The photoperiod effect continued even after seedlings were subjected at consistent photoperiod. Overall, "short" photoperiods could provide "better" P. brutia seedlings to accommodate immediate massive reforestation and afforestation needs.

  15. Genetic diversity of seagrass seeds influences seedling morphology and biomass.

    Science.gov (United States)

    Randall Hughes, A; Hanley, Torrance C; Schenck, Forest R; Hays, Cynthia G

    2016-12-01

    Genetic diversity can influence ecological processes throughout ontogeny, yet whether diversity at early life history stages is important in long-lived taxa with overlapping generations is unclear. Seagrass systems provide some of the best evidence for the ecological effects of genetic diversity among adult shoots, but we do not know if the genetic diversity of seeds and seedlings also influences seagrass ecology. We tested the effects of seagrass (Zostera marina) seed diversity and relatedness on germination success, seedling morphology, and seedling production by comparing experimental assemblages of seeds collected from single reproductive shoots ("monocultures") to assemblages of seeds collected from multiple reproductive shoots ("polycultures"). There was no difference in seedling emergence, yet seedlings from polycultures had larger shoots above and below ground than seedlings from monocultures at the end of the 1-yr experiment. Genetic relatedness of the seedlings predicted some aspects of shoot morphology, with more leaves and longer roots and shoots at intermediate levels of relatedness, regardless of seed diversity. Our results suggest that studies of only adult stages may underestimate the importance of genetic diversity if the benefits at early life history stages continue to accrue throughout the life cycle. © 2016 by the Ecological Society of America.

  16. Seed Germination and Seedling Survival of Spartina alterniflora Loisel

    Directory of Open Access Journals (Sweden)

    Patrick D. Biber

    2008-01-01

    Full Text Available Spartina alterniflora (smooth cordgrass is a widespread intertidal salt marsh plant that is frequently used in coastal restoration projects. Seeds collected in 2004 were tested for seed germination and seedling survival after 6 months of cold seed storage to determine differences among collection locations (experiment 1. Seeds collected in 2005, after Hurricane Katrina, were tested for seed germination and seedling survival from 0 to 15 months of cold seed storage time to determine minimum and maximum storage time and seedling survival rates (experiment 2. Seed germination increased from 1-4 months of cold, wet storage (stratification and then began to decline. Survival of the seedlings was highest after 2 months of stratification. In experiment 1, seedling size was found to vary widely among seedlings of the same source and age. Seedling height at 22 days after planting ranged from 2-16 cm, despite identical environmental conditions. Selective breeding could target plants with fast early growth characteristics to promote strains that can be raised quickly in a nursery in response to demands for restoration.

  17. Germination and initial development of aroeira (Myracrodruon urundeuva seedlings

    Directory of Open Access Journals (Sweden)

    Silvana de Paula Quintão Scalon

    2012-12-01

    Full Text Available Aroeira has great economic importance due to its wood useful, tannins extraction and use in the pharmacology. The aim of this work was to evaluate the germination aspects and initial seedlings development of aroeira, under gibberellins, substrata and shading effects, and for that two experiments were led out. In the first one, seeds were previously soaked for 24 hours in water and in 100 mg.L-1 gibberellin solution and were sowed directly in cells trays in the following substrata: land and sand (1:1 and 1:2 and Plantmax . In the second experiment, 15 cm length seedlings were transplanted to polyethylene sacks filled out land+sand+poultry manure (1:1:1 partly decomposed and they were maintained at greenhouse for 15 days. Soon after, seedlings were transferred for the following conditions: shading (50% and full sun and they were 50 mg.L-1 and 150 mg.L-1 gibberellins solutions pulverized, as control seedlings water pulverized. Aroeira seeds should not be previously water or gibberellins imbibed before being sowed. The best substrata for aroeira seeds germination was Plantmax without germinative treatments to reach higher than 80% of seedlings survival. The seedlings developed better at full sun light and the gibberellin. It was observed increment in height, diameter, foliar area and fresh and dry mass from aerial and root part when compared to shading situation. The gibberellins applications did not influence the aroeira seedlings initial growth characteristics.

  18. Effects of benzoic acid and cadmium toxicity on wheat seedlings

    Directory of Open Access Journals (Sweden)

    Kavita Yadav

    2013-06-01

    Full Text Available Benzoic acid (BA and Cd exhibit cumulative effects on plants due to their accumulation in the soil. The present study reports the effects of BA an allelochemical, Cd and their combinations on seed germination, seedling growth, biochemical parameters, and response of antioxidant enzymes in Triticum aestivum L. The experiment was conducted in sand supplemented with Hoagland nutrient solution. Benzoic acid was applied at concentrations of 0.5, 1.0, and 1.5 mM with or without Cd (7 mg L-1 to observe effects of allelochemical and Cd alone and in combination on wheat. Both stresses exhibited inhibitory effect on growth and metabolism of wheat seedlings. The allelochemical in single and combined treatments with Cd decreased seedling growth as compared to Cd stress. The two stresses significantly enhanced malondialdehyde content of wheat seedlings. The activity of other antioxidant enzymes, viz. superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase (APX, and guaiacol peroxidase (POX were also recorded. SOD increased in seedlings under the two stresses. CAT more prominently ameliorates the toxic effects of H2O2 as compared with APX and POX and protected wheat seedlings from oxidative stress. Allelochemical buttressed the toxic effect of Cd on wheat seedlings.

  19. Survivel, growth, and nutrition of tree seedlings fertilized at planting on Andisol soils in Iceland

    DEFF Research Database (Denmark)

    Oskarsson, Hreinn; Sigurgeirsson, Adalsteinn; Raulund-Rasmussen, Karsten

    2006-01-01

    Ledeb. and Picea sitchensis (Bong.) Carr. After six growing seasons, seedlings provided with controlled-release-fertilizer (Osmocote®: 25 g per seedling) or smaller amounts of easily soluble nitrogen–phosphorus fertilizer (e.g. 1.2 g N per seedling and 1.4 g P per seedling) showed significantly improved...

  20. Early field performance of Acacia koa seedlings grown under subirrigation and overhead irrigation

    Science.gov (United States)

    Anthony S. Davis; Jeremiah R. Pinto; Douglass F. Jacobs

    2011-01-01

    Koa (Acacia koa A. Gray [Fabaceae]) seedlings were grown with subirrigation and overhead irrigation systems in an effort to characterize post-nursery field performance. One year following outplanting, we found no differences in seedling height or survival, but root-collar diameter was significantly larger for subirrigated seedlings. This indicates that koa seedlings,...

  1. Growth of ponderosa pine seedlings as affected by air pollution

    Science.gov (United States)

    Momen, B.; Anderson, P. D.; Houpis, J. L. J.; Helms, J. A.

    The effect of air pollution on seedling survival and competitive ability is important to natural and artificial regeneration of forest trees. Although biochemical and physiological processes are sensitive indicators of pollution stress, the cumulative effects of air pollutants on seedling vigor and competitive ability may be assessed directly from whole-plant growth characteristics such as diameter, height, and photosynthetic area. A few studies that have examined intraspecific variation in seedling response to air pollution indicate that genotypic differences are important in assessing potential effects of air pollution on forest regeneration. Here, we studied the effects of acid rain (no-rain, pH 5.1 rain, pH 3.0 rain) and ozone (filtered, ambient, twice-ambient) in the field on height, diameter, volume, the height:diameter ratio, maximum needle length, and time to reach maximum needle length in seedlings of three families of ponderosa pine ( Pinus ponderosa Dougl. ex Laws). Seedling diameter, height, volume, and height:diameter ratio related significantly to their pre-treatment values. Twice-ambient ozone decreased seedling diameter compared with ozone-filtered air. A significant family-by-ozone interaction was detected for seedling height, as the height of only one of the three families was decreased by twice-ambient ozone compared with the ambient level. Seedling diameter was larger and the height:diameter ratio was smaller under pH 3.0 rain compared to either the no-rain or the pH 5.1-rain treatment. This suggests greater seedling vigor, perhaps due to a foliar fertilization effect of the pH 3.0 rain.

  2. BIM LAU-PE: Seedlings in Microgravity

    Science.gov (United States)

    Gass, S.; Pennese, R.; Chapuis, D.; Dainesi, P.; Nebuloni, S.; Garcia, M.; Oriol, A.

    2015-09-01

    The effect of gravity on plant roots is an intensive subject of research. Sounding rockets represent a costeffective platform to study this effect under microgravity conditions. As part of the upcoming MASER 13 sounding rocket campaign, two experiments on Arabidopsis thaliana seedlings have been devised: GRAMAT and SPARC. These experiments are aimed at studying (1) the genes that are specifically switched on or off during microgravity, and (2) the position of auxin-transporting proteins during microgravity. To perform these experiments, RUAG Space Switzerland site of Nyon, in collaboration with the Swedish Space Corporation (SSC) and the University of Freiburg, has developed the BIM LAU-PE (Biolology In Microgravity Late Access Unit Plant Experiment). In the following an overview of the BIM LAU-PE design is presented, highlighting specific module design features and verifications performed. A particular emphasis is placed on the parabolic flight experiments, including results of the micro-g injection system validation.

  3. Arborescent palm seed morphology and seedling distribution

    Directory of Open Access Journals (Sweden)

    Rodolfo Salm

    Full Text Available This study examines how the seed morphology of two large arborescent palms, Attalea maripa (Aubl. Mart. and Astrocaryum aculeatum G. Mey, may affect their seed shadow in a seasonally dry Amazonian forest. In addition to being smaller and produced in larger numbers than those of A. aculeatum, A. maripa seeds also presented a substantially lower amount of nutritional reserves available for the embryo. However, A. maripa seedlings were found in much higher numbers than those of A. aculeatum. The results suggest that, within the spatial scale considered, the seed rain of A. maripa is more restricted to the area surrounding around reproductive conspecifics than that of A. aculeatum. Furthermore, in comparison with those of A. aculeatum, the smaller seeds of A. maripa might be less attractive to scatterhoarding rodents (e.g. Dasyprocta aguti. The pattern observed emphasizes the importance of scatterhoarding rodents as dispersers of large-seeded plant species in Neotropical forests.

  4. Arborescent palm seed morphology and seedling distribution.

    Science.gov (United States)

    Salm, Rodolfo

    2005-11-01

    This study examines how the seed morphology of two large arborescent palms, Attalea maripa (Aubl.) Mart. and Astrocaryum aculeatum G. Mey, may affect their seed shadow in a seasonally dry Amazonian forest. In addition to being smaller and produced in larger numbers than those of A. aculeatum, A. maripa seeds also presented a substantially lower amount of nutritional reserves available for the embryo. However, A. maripa seedlings were found in much higher numbers than those of A. aculeatum. The results suggest that, within the spatial scale considered, the seed rain of A. maripa is more restricted to the area surrounding around reproductive conspecifics than that of A. aculeatum. Furthermore, in comparison with those of A. aculeatum, the smaller seeds of A. maripa might be less attractive to scatterhoarding rodents (e.g. Dasyprocta aguti). The pattern observed emphasizes the importance of scatterhoarding rodents as dispersers of large-seeded plant species in Neotropical forests.

  5. Tree Seed and Seedling Supply Systems

    DEFF Research Database (Denmark)

    Nyoka, Betserai I.; Roshetko, James M.; Jamnadass, Ramni

    2015-01-01

    The paper reviews tree seed and seedling supply systems in sub-Saharan Africa, Asia and Latin America. Across these regions, the review found that some of the germplasm supply systems do not efficiently meet farmers’ demands and environmental expectations in terms of productivity, species...... and genetic diversity. In some countries, germplasm used is mostly sourced from undocumented sources and often untested. Germplasm quality control systems are only found in a few countries. Appreciation of the value of tree germplasm of high genetic quality is low. Non-government organisations (NGOs) in many...... out private entrepreneurs, although this is not substantiated by any evidence to suggest that the smallholder farmers are willing and able to pay for the germplasm. In some Latin American countries, private companies, government and NGOs provide farmers tree germplasm in a partnership in which farmers...

  6. Fungicidal control of Lophodermium seditiosum on Pinus sylvestris seedlings in Swedish forest nurseries

    Energy Technology Data Exchange (ETDEWEB)

    Stenstroem, Elna [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology; Arvidsson, Bernt [Svenska Skogsplantor AB, Joenkoeping (Sweden)

    2001-07-01

    During the 1990s, there were serious outbreaks of the pathogen Lophodermium seditiosum on pine seedlings in Swedish forest nurseries, even though the seedlings had been treated with the fungicide propiconazole. The present experiment was carried out to evaluate two other fungicides, fluazinam and azoxystrobin, as possible alternatives to propiconazole. In the tests, which were all carried out in the same forest nursery, seedlings were treated with either propiconazole, fluazinam. or azoxystrobin, and the proportion of needles with ascocarps of L. seditiosum and the number of ascocarps per needle were recorded over the following 2 yrs. Seedlings treated with azoxystrobin already appeared healthier than control seedlings in September of the first year, and by November all azoxystrobin-treated seedlings had fewer ascocarps per needle compared with control seedlings. In autumn of the second year, there were no ascocarps on seedlings treated with fluazinam or azoxystrobin, whereas seedlings treated with propiconazole had similar numbers of ascocarps to non-treated control seedlings.

  7. Substrate influences ecophysiological performance of tree seedlings.

    Science.gov (United States)

    Pröll, Gisela; Hietz, Peter; Delaney, Christina M; Katzensteiner, Klaus

    2016-01-01

    Unfavourable soil conditions frequently limit tree regeneration in mountain forests on calcareous bedrock. Rocky, shallow organic soils on dolomite pose a particular problem for tree regeneration due to commonly restricted water and nutrient supplies. Moreover, an often dense layer of understorey vegetation competes for the limited resources available. Hence, an array of interacting factors impairs tree seedlings' performance on dolomite, but there is little information on the ecophysiological mechanisms. We studied the effects of substrate, competing vegetation and foliar nutrient concentrations on the photosynthetic rate (A), stomatal conductance (gs) and leaf water potentials (ψ) of sycamore (Acer pseudoplatanus L.), beech (Fagus sylvatica L.), spruce [Picea abies (L.) Karst.] and larch (Larix decidua Mill.) under controlled (well-watered/drought-stressed) conditions and under prevailing field conditions. While A and gs of well-watered spruce in the pot experiment were reduced by the mineral substrate, the organic dolomite substrate with dense competing vegetation reduced gs and ψ of sycamore, spruce and larch under drought-stressed conditions in the field. For sycamore and spruce, A and gs were strongly correlated with foliar nitrogen (N) and potassium (K) concentrations in the pot experiment. In contrast, soil water primarily affected beech and larch. Finally, dense competing vegetation negatively affected A and gs of spruce and A of larch on dolomite. Our results highlight the critical role of N, K and water availability for tree seedlings in shallow soils on calcareous bedrock. On these sites, natural tree regeneration is at particular risk from episodic drought, a likely consequence of climate change.

  8. Biological seed priming mitigates the effects of water stress in sunflower seedlings

    OpenAIRE

    Singh, Narsingh Bahadur; Singh, Deepmala; Singh, Amit

    2015-01-01

    The sunflower (Helianthus annuus L. cv. PAC 36) seedlings were inoculated with plant growth promoting rhizobacteria (PGPR), viz. Azotobacter chroococcum (A+), Bacillus polymyxa (B+), separately and in combination of the two (AB+). Relative water content and seedling growth were maximum in AB+ seedlings under control. Water stress significantly decreased the RWC, growth and dry mass of non-inoculated seedlings. However, inoculated seedlings maintained higher growth even under water stress. Pig...

  9. A leaf phosphorus assay for seedlings of Acacia mangium.

    Science.gov (United States)

    Sun, J S; Simpson, R J; Sands, R

    1992-10-01

    Concentrations of extractable and total phosphorus in leaves, stem, root and nodules of 12-week-old seedlings of two provenances of Acacia mangium Willd. were analyzed to identify the fraction of phosphorus and the plant part most suitable for predicting the phosphorus nutritional status of the seedlings.For both provenances, concentrations of extractable phosphorus were more sensitive to changes in soil phosphorus status and varied less among different plant parts than concentrations of total phosphorus. Concentrations of extractable phosphorus in the youngest fully expanded leaf (Leaf 3 from the apex) and the next two older leaves correlated closely with seedling dry mass and may be used to assess the phosphorus nutritional status of Acacia mangium seedlings.

  10. Strong microsite control of seedling recruitment in tundra

    DEFF Research Database (Denmark)

    Graae, Bente J; Ejrnæs, Rasmus; Lang, Simone I

    2011-01-01

    , the experimental seed addition showed that the microsite environment was even more important. For all species, seedling emergence peaked at the productive end of the gradient, irrespective of the adult niches realized. Disturbance promoted recruitment at all positions along the environmental gradient, not just......The inclusion of environmental variation in studies of recruitment is a prerequisite for realistic predictions of the responses of vegetation to a changing environment. We investigated how seedling recruitment is affected by seed availability and microsite quality along a steep environmental...... at high productivity. Early seedling emergence constituted the main temporal bottleneck in recruitment for all species. Surprisingly, winter mortality was highest at what appeared to be the most benign end of the gradient. The results highlight that seedling recruitment patterns are largely determined...

  11. Seedlings and Saplings - Spears and Didion Ranches [ds318

    Data.gov (United States)

    California Department of Resources — These data are the total number and average number of saplings and seedlings of trees detected from 0.05-ha circular plot habitat samples taken in 2005 at sample...

  12. Identification of zygotic and nucellar seedlings in polyembryonic mango cultivars

    Directory of Open Access Journals (Sweden)

    Elisa del Carmen Martínez Ochoa

    2012-11-01

    Full Text Available The objective of this work was to evaluate the occurrence of polyembryony in the mango cultivars Manila and Ataulfo, and to determine whether seedlings cultured in vitro are zygotic or nucelar. Percentage of polyembryony was calculated and the number of embryos in 100 seeds of each cultivar was recorded. 'Manila' exhibited 97% polyembryony with 3.4 embryos per seed, while 'Ataulfo' had 95% polyembryony with 3.2 embryos per seed. Later, 20 seeds of each cultivar were established in vitro, and it was analyzed those in which all embryos germinated (12 seeds from 'Manila' and 7 from 'Ataulfo'. DNA was extracted from seedling leaf tissue, and its origin was identified with 14 RAPD primers. The polymorphic markers recognized the seedlings of sexual origin in seven of nine 'Manila' polyembryonic seeds, and in four of seven 'Ataulfo' ones. Also, in polyembryonic seeds not all zygotic seedlings were produced by small embryos located at the micropyle.

  13. Multivariate and Clustering Analysis in Sweet Tamarind Seedling Progenies

    OpenAIRE

    D. Saraladevi, V. Ponnuswami, R.M. Vijayakumar and S.Chitra

    2010-01-01

    Seventy eight seedling progenies of a sweet tamarind type collected from Dindigul region were planted at HorticulturalCollege and Research Institute, Periyakulam during September 2005. These seedling progenies in pre bearing stagewere evaluated to assess the variability existing in respect of growth parameters viz., tree height, girth and canopyspread. Among the three characters studied, canopy spread exhibited highest correlation with girth (0.61) than treeheight (0.21). Tree height having h...

  14. Study on Quantitative Character for Anatomy in Tomato Seedling Stem

    Institute of Scientific and Technical Information of China (English)

    LI Fuheng; WEI Liyan; YU Longfeng; QI Donglai; ZHANG Da

    2009-01-01

    The results of quantitative characters for anatomy in stems of three varieties tomatoes seedlings showed that the cell population between vascular bundle and epidermis, the cellular layers among vascular bundles and the cell population in an unit area(mm2) of no vascular bundle areas were similar and there had small difference among three varieties. On the foundation of these studies, the developmental mechanism of tomato seedling stem was discussed.

  15. Silvicultural Attempts to Induce Browse Resistance in Conifer Seedlings

    Directory of Open Access Journals (Sweden)

    Bruce A. Kimball

    2011-01-01

    Full Text Available A multiyear study was conducted to determine if soil amendment combined with topical application of elemental sulfur could be employed to reduce deer browse damage to four conifer species. Fertilizer and sulfur were applied to conifer seedlings at seven sites near Corvallis, OR. Growth and browse damage data were collected for all seedlings over a period of 17 months. Additionally, foliar concentrations of monoterpenes and simple carbohydrates were assessed in western redcedar (Thuja plicata seedlings over a period of three years. Fertilization and sulfur treatments had a moderate impact on growth and no influence on browse damage or the chemical responses. Over the course of the study, browse damage diminished while foliar monoterpene concentrations increased in redcedar. It appears that silvicultural manipulation via sulfur application and/or soil amendment cannot accelerate or alter the ontogenetical changes that may naturally defend seedlings against mammalian herbivores. In a brief trial with captive deer, redcedar browse resistance was influenced by seedling maturation, but not monoterpene content. Other maturation effects may yield significant browse protection to young seedlings.

  16. Eucalyptus obliqua seedling growth in organic vs. mineral soil horizons.

    Science.gov (United States)

    Barry, Karen M; Janos, David P; Nichols, Scott; Bowman, David M J S

    2015-01-01

    Eucalyptus obliqua, the most widespread timber tree in Tasmania, is a pioneer after fire which can eliminate the organic layer of forest soil, exposing the underlying mineral soil. We compared seedling growth, mycorrhiza formation, and mineral nutrient limitation in organic layer vs. mineral soil. We grew E. obliqua seedlings separately in pots of organic layer and mineral soil in a glasshouse. Additional treatments of organic soil only, involved fully crossed methyl-bromide fumigation and fertilization. Fertilization comprised chelated iron for 121 days after transplant (DAT) followed by soluble phosphorus. At 357 DAT, whole plant dry weight was three times greater in ambient organic than in mineral soil. In organic soil, fumigation halved ectomycorrhiza abundance and reduced seedling growth at 149 DAT, but by 357 DAT when negative effects of fumigation on seedling growth had disappeared, neither fumigation nor fertilization affected mycorrhiza abundance. Iron fertilization diminished seedling growth, but subsequent phosphorus fertilization improved it. E. obliqua seedlings grow much better in organic layer soil than in mineral soil, although phosphorus remains limiting. The prevalent forestry practice of burning to mineral soil after timber harvest exposes a poor growth medium likely only partially compensated by fire-induced mineral soil alterations.

  17. Eucalyptus obliqua seedling growth in organic versus mineral soil horizons

    Directory of Open Access Journals (Sweden)

    Karen eBarry

    2015-02-01

    Full Text Available Eucalyptus obliqua, the most widespread timber tree in Tasmania, is a pioneer after fire which can eliminate the organic layer of forest soil, exposing the underlying mineral soil. We compared seedling growth, mycorrhiza formation, and mineral nutrient limitation in organic layer versus mineral soil. We grew E. obliqua seedlings separately in pots of organic layer and mineral soil in a glasshouse. Additional treatments of organic soil only, involved fully crossed methyl-bromide fumigation and fertilization. Fertilization comprised chelated iron for 121 days after transplant (DAT followed by soluble phosphorus. At 357 DAT, whole plant dry weight was three times greater in ambient organic than in mineral soil. In organic soil, fumigation halved ectomycorrhiza abundance and reduced seedling growth at 149 DAT, but by 357 DAT when negative effects of fumigation on seedling growth had disappeared, neither fumigation nor fertilization affected mycorrhiza abundance. Iron fertilization diminished seedling growth, but subsequent phosphorus fertilization improved it. E. obliqua seedlings grow much better in organic layer soil than in mineral soil, although phosphorus remains limiting. The prevalent forestry practice of burning to mineral soil after timber harvest exposes a poor growth medium likely only partially compensated by fire-induced mineral soil alterations.

  18. Growth of white tabebuia seedlings in different substrates

    Directory of Open Access Journals (Sweden)

    Marichel Canazza de Macedo

    2011-03-01

    Full Text Available The objective of this work was to evaluate the white tabebuia (Tabebuia roseo-alba (Ridl. Sandwith seedlings emergence and growth in the beds according to different substrates. Two independent experiments were conducted. The emergence study was carried out in six substrates: 1- Plantmax®; 2- vermiculite; 3- sand; 4- soil + sand (1:1; 5- soil + carbonized rice husk (1:1; 6- soil + sand + carbonized rice husk (2:1:1 (v/v, and the experiment was set up according to a three-replicate randomized complete-block design. The growth study of seedlings was carried out according to a five-replicate randomized complete-block design with five substrates: 1- soil + sand (1:1; 2- soil + semi decomposed chicken manure (1:1; 3- soil + carbonized rice husk (1:1; 4- soil + sand + semi decomposed chicken manure (1:1:1; 5- soil + sand + carbonized rice husk (1:1:1 (v/v. The height results of seedling emergence, emergence speed index and the stem height were observed with Plantmax®, vermiculite, soil + carbonized rice husk and soil + sand + carbonized rice husk. The best results of seedling height, stem diameter, chlorophyll index, leaf area, root length and the stem dry mass weight and root were observed in the substrates with semi decomposed chicken manure. It is recommended the use of P, V, SC or SAC for seedling germination and emergence and SACF or SCF for seedling growth of white tabebuia.

  19. Wood formation in Abies balsamea seedlings subjected to artificial defoliation.

    Science.gov (United States)

    Rossi, Sergio; Simard, Sonia; Deslauriers, Annie; Morin, Hubert

    2009-04-01

    We determined the cambial sensitivity and quantified the anatomical differences in xylem of Abies balsamea (L.) Mill. seedlings subjected to artificial defoliation to simulate spruce budworm feeding. Defoliation was performed by removing two-thirds of needles of all current-year shoots for up to four consecutive growth cycles to account for inter- and intra-annual xylem formation. In Experiment 1, xylem development was studied from May to October 2005 in seedlings defoliated at the end of June. In Experiment 2, anatomical features of the xylem were measured along the tree rings formed in 2005 and 2006 during the four cycles of growth and defoliation. Control and defoliated seedlings showed similar patterns of cambial activity and timing of xylem differentiation, although fewer enlarging cells were observed in August to September in defoliated seedlings. Tree-ring widths were similar in control and defoliated seedlings, with thinner rings produced in the greenhouse in winter. No effect of defoliation on cell lumen area was observed, and effects on radial cell diameter and wall thickness were found only occasionally. The results indicate that the A. balsamea seedlings produced all the resources required to maintain stem growth during the four cycles of defoliation.

  20. Phosphorus requirements for containerized Pterocarpus indicus seedlings

    Institute of Scientific and Technical Information of China (English)

    Eng Hai Lok; Bernard Dell

    2015-01-01

    Pterocarpus indicus Willd is a tropical woody legume that holds promise for plantation forestry. Two glasshouse experiments were undertaken on two soil types to determine the phosphorus (P) concentration ranges in the foliage of P-stressed and healthy plants, and to define cri-tical P concentrations for the diagnosis of deficiency and toxicity. There was a narrow range in rates of P fertilizer, supplied as Ca(H2PO4)2?H20, between deficiency and toxicity compared to other tree species. The relationship between shoot yield and P concentration in the youngest fully expanded leaf enabled critical P concentrations for the diagnosis of deficiency (0.17%) and toxicity (0.41%) to be determined at 90% maximum yield from linear re-gressions fitted to the data. The foliar P concentration ranges for deficiency and toxicity were similar to other nitrogen-fixing trees. The defined P concentration ranges and the critical P concentrations for the diagnosis of P deficiency and P toxicity should be useful for monitoring the P status of nursery stock and the health of young seedlings after out-planting.

  1. The Vibration Ring. Phase 1; [Seedling Fund

    Science.gov (United States)

    Asnani, Vivake M.; Krantz, Timothy L.; Delap, Damon C.; Stringer, David B.

    2014-01-01

    The vibration ring was conceived as a driveline damping device to prevent structure-borne noise in machines. It has the appearance of a metal ring, and can be installed between any two driveline components like an ordinary mechanical spacer. Damping is achieved using a ring-shaped piezoelectric stack that is poled in the axial direction and connected to an electrical shunt circuit. Surrounding the stack is a metal structure, called the compression cage, which squeezes the stack along its poled axis when excited by radial driveline forces. The stack in turn generates electrical energy, which is either dissipated or harvested using the shunt circuit. Removing energy from the system creates a net damping effect. The vibration ring is much stiffer than traditional damping devices, which allows it to be used in a driveline without disrupting normal operation. In phase 1 of this NASA Seedling Fund project, a combination of design and analysis was used to examine the feasibility of this concept. Several designs were evaluated using solid modeling, finite element analysis, and by creating prototype hardware. Then an analytical model representing the coupled electromechanical response was formulated in closed form. The model was exercised parametrically to examine the stiffness and loss factor spectra of the vibration ring, as well as simulate its damping effect in the context of a simplified driveline model. The results of this work showed that this is a viable mechanism for driveline damping, and provided several lessons for continued development.

  2. Gene expression in plant lipid metabolism in Arabidopsis seedlings.

    Directory of Open Access Journals (Sweden)

    An-Shan Hsiao

    Full Text Available Events in plant lipid metabolism are important during seedling establishment. As it has not been experimentally verified whether lipid metabolism in 2- and 5-day-old Arabidopsis thaliana seedlings is diurnally-controlled, quantitative real-time PCR analysis was used to investigate the expression of target genes in acyl-lipid transfer, β-oxidation and triacylglycerol (TAG synthesis and hydrolysis in wild-type Arabidopsis WS and Col-0. In both WS and Col-0, ACYL-COA-BINDING PROTEIN3 (ACBP3, DIACYLGLYCEROL ACYLTRANSFERASE1 (DGAT1 and DGAT3 showed diurnal control in 2- and 5-day-old seedlings. Also, COMATOSE (CTS was diurnally regulated in 2-day-old seedlings and LONG-CHAIN ACYL-COA SYNTHETASE6 (LACS6 in 5-day-old seedlings in both WS and Col-0. Subsequently, the effect of CIRCADIAN CLOCK ASSOCIATED1 (CCA1 and LATE ELONGATED HYPOCOTYL (LHY from the core clock system was examined using the cca1lhy mutant and CCA1-overexpressing (CCA1-OX lines versus wild-type WS and Col-0, respectively. Results revealed differential gene expression in lipid metabolism between 2- and 5-day-old mutant and wild-type WS seedlings, as well as between CCA1-OX and wild-type Col-0. Of the ACBPs, ACBP3 displayed the most significant changes between cca1lhy and WS and between CCA1-OX and Col-0, consistent with previous reports that ACBP3 is greatly affected by light/dark cycling. Evidence of oil body retention in 4- and 5-day-old seedlings of the cca1lhy mutant in comparison to WS indicated the effect of cca1lhy on storage lipid reserve mobilization. Lipid profiling revealed differences in primary lipid metabolism, namely in TAG, fatty acid methyl ester and acyl-CoA contents amongst cca1lhy, CCA1-OX, and wild-type seedlings. Taken together, this study demonstrates that lipid metabolism is subject to diurnal regulation in the early stages of seedling development in Arabidopsis.

  3. Venus Flytrap Seedlings Show Growth-Related Prey Size Specificity

    Directory of Open Access Journals (Sweden)

    Christopher R. Hatcher

    2014-01-01

    Full Text Available Venus flytrap (Dionaea muscipula has had a conservation status of vulnerable since the 1970s. Little research has focussed on the ecology and even less has examined its juvenile stages. For the first time, reliance on invertebrate prey for growth was assessed in seedling Venus flytrap by systematic elimination of invertebrates from the growing environment. Prey were experimentally removed from a subset of Venus flytrap seedlings within a laboratory environment. The amount of growth was measured by measuring trap midrib length as a function of overall growth as well as prey spectrum. There was significantly lower growth in prey-eliminated plants than those utilising prey. This finding, although initially unsurprising, is actually contrary to the consensus that seedlings (traps < 5 mm do not catch prey. Furthermore, flytrap was shown to have prey specificity at its different growth stages; the dominant prey size for seedlings did not trigger mature traps. Seedlings are capturing and utilising prey for nutrients to increase their overall trap size. These novel findings show Venus flytrap to have a much more complex evolutionary ecology than previously thought.

  4. LIMING AND FERTILIZING FOR MAHOGANI (Switenia macrophylla King. SEEDLING FORMATION

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Franco Tucci

    2007-09-01

    Full Text Available The production of seedlings is one of the most important phases of the cultivation of forest species. Seedlings ofappropriate quality are fundamental in the growth and development of the species. In the production of seedlings, the substratum isfundamental for the good development of the plants. However, the subsoil in general, is acid and it contains low levels of nutritious.The acidity of the soil and the deficiency of nutrients can be corrected through liming and mineral fertilization. The objective of thepresent work was to evaluate the effect of liming and of the fertilization of the soil for the production of mahogany seedlings. Theexperiment was carried out in the period of 120 days, in the Federal University of Amazonas, UFAM. The experimental design wasrandomized complete blocks with statistical analysis in split plot. The plots were composed with eight treatments and four repetitionsand the subplots were eight sampling times of the plants. The treatments were control (natural soil, liming, corrective phosphate,fertilizing with NPK, liming + corrective phosphate, corrective phosphate + fertilizing with NPK, liming + fertilizing with NPK andliming + corrective phosphate + fertilizing with NPK. It was concluded that the associated liming and corrective phosphate and withthe fertilizing with nitrogen, phosphorous and potassium promoted the smallest levels of exchangeable aluminum and the largestlevels of calcium, magnesium, phosphorous and potassium in the soil. These levels of nutrients in the soil caused larger levels ofnutrients in the plants, providing larger growth rate. The liming, corrective phosphate and fertilizing are a fundamental practices inthe formation of mahogany seedlings.

  5. Why are there few seedlings beneath the myrmecophyte Triplaris americana?

    Science.gov (United States)

    Larrea-Alcázar, Daniel M.; Simonetti, Javier A.

    2007-07-01

    We compared the relative importance of chemical alellopathy, pruning behaviour of resident ants and other non-related agents to ant-plant mutualism for seedling establishment beneath Triplaris americana L. (Polygonaceae), a myrmecophyte plant. We also included a preliminary analysis of effects of fragmentation on these ecological processes. Seeds and seedlings of Theobroma cacao L. (Sterculiaceae) were used as the target species in all experiments. Leaf-tissue extracts of the myrmecophyte plant did not inhibit germination of cacao seeds. Resident Pseudomyrmex triplarinus Weddell (Pseudomyrmecinae) ants did not remove seeds under the canopy of their host plants. The main seed consumer was the leaf-cutting ant Atta sexdens L. (Myrmicinae). Leaves of cacao seedlings were partially or totally pruned by Pseudomyrmex ants mainly in forest fragments studied. We offer evidence pointing to the possibility that the absence of seedlings beneath Triplaris may result from effects of both ant species. We discuss the benefits of pruning behaviour for the resident ant colony and the effects of ant-ant interactions on seedling establishment beneath this ant-plant system.

  6. Growth and nutrients tenor in soursop seedlings cultivated

    Directory of Open Access Journals (Sweden)

    Rosiane de Lourdes Silva de Lima

    2009-12-01

    Full Text Available Although it is being recommended small containers, such as plastic tubes for seedling production of fruit trees, it is still necessary to study a suitable substrate for use in nursery. This experiment aimed to evaluate the effects of six organic components of the substrate on the growth and mineral composition of soursop seedlings in plastic tubes. For this purpose were evaluated six substrates: 1 Earthworm humus (HM + carbonized rice husk (CAC, 2 HM + powder coconut husk (PCCS, 3 HM + carnauba straw (BC , 4 CAC + PCCS, 5 CAC + BC and 6 PCCS + BC, being the treatments distributed in a randomized block design with four replications. Four months after sowing were evaluated the seedling growth and determined the nutrient concentration in leaves. The seedlings presented suitable vigor in substrates formed by the mixture of soil, earthworm humus, rice husk, powdered coconut husk or carnauba straw, in the volume ratio of 2:1:1. Substrates composed only by mixing soil, carbonized rice husk, powder coconut husk or carnauba straw do not allow adequate growth and nutrition in the formation of soursop seedlings.

  7. Effects of clouds and ozone on red spruce seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Pier, P.A.; Thornton, F.C.; McDuffie, C. Jr. (Tennessee Valley Authority, Muscle Shoals, AL (USA))

    1989-04-01

    Potted native and Phyton-grown (Phyton Technologies) red spruce seedlings were placed in open-top field chambers constructed on Whitetop Mountain, VA (elevation 1680 m) to evaluate the effect of ozone and acid cloud deposition on seedling growth and metabolism. Chamber treatments were (1) exclusion of clouds and an approximate 50% reduction in ambient ozone, (2) ambient ozone with clouds excluded, and (3) exposure to clouds and ambient ozone (control). No differences were detected between chamber treatments for diameter growth, total chlorophyll, chl a and b, chl a/b ratio, and carotenoids. No enhancement of photosynthesis and respiration was seen in exclusion chambers for current and previous year's growth of native seedlings during the growing season. Photosynthesis of Phyton-grown seedlings was consistently higher in exclusion chambers compared to control chambers over the course of the growing season, although differences were not statistically significant. After one growing season, neither pollutant had significant effects on seedling growth and metabolism.

  8. Degraded dryland rehabilitation: boosting seedling survival using zeolitic tuff

    Science.gov (United States)

    Alhamad, Mohammad Noor; Alrbabah, Mohammad; Athamneh, Hana

    2016-04-01

    More than 90% of Jordan is broadly defined as rangelands. Most rangelands are located within the arid zone of the country. Extensive grazing occurs across much of the natural pastures resulting in serious environmental degradation of natural resources in these rangelands. Several programs were carried out for rangeland conservation and rehabilitation in the country. However, these programs face a major challenge of the low survival rate of transplanted shrub seedlings. Seeking innovative approaches to assure healthy establishment of seedling is a big challenge to achieve successful rehabilitation programs. Drought is considered one of the major problems in rehabilitation. Promoting survival and growth, using zeolitic tuff added to planting holes is suggested to be a possible solution. The experiment was conducted on a factorial arrangement within RCBD design. Two shrub species (Atriplex halimus, Atriplex nummularia) were transplanted into holes prepared with three levels of tuff treatments (mulching, mixing and control) under rainfed condition. The result showed insignificant effect of tuff on seedling survival percentage, when mixing tuff with plantation soil or adding tuff as mulch. Also, the two species showed similar survival percentages over two measured dates. However, mixing tuff with soil during hole preparation significantly enhanced seedling heights. Furthers, The Australian atriplex (Atriplex nummularia) species significantly grow higher than Atriplex halimus. The study results suggested that mixing zeoltic tuff with soil during transplantation of seedling is promising in improving the success of rangeland rehabilitation in dry areas in Jordan.

  9. Symbiotic propagation of seedlings of Cyrtopodium glutiniferum Raddi (Orchidaceae

    Directory of Open Access Journals (Sweden)

    Fernanda Aparecida Rodrigues Guimarães

    2013-09-01

    Full Text Available In nature, orchid seeds obtain the nutrients necessary for germination by degrading intracellular fungal structures formed after colonization of the embryo by mycorrhizal fungi. Protocols for asymbiotic germination of orchid seeds typically use media with high concentrations of soluble carbohydrate and minerals. However, when reintroduced into the field, seedlings obtained via asymbiotic germination have lower survival rates than do seedlings obtained via symbiotic germination. Tree fern fiber, the ideal substrate for orchid seedling acclimatization, is increasingly scarce. Here, we evaluated seed germination and protocorm development of Cyrtopodium glutiniferum Raddi cultivated in asymbiotic media (Knudson C and Murashige & Skoog and in oatmeal agar (OA medium inoculated with the mycorrhizal fungus Epulorhiza sp., using non-inoculated OA medium as a control. We also evaluated the performance of tree fern fiber, pine bark, eucalyptus bark, corncob and sawdust as substrates for the acclimatization of symbiotically propagated plants. We determined germination percentages, protocorm development and growth indices at 35 and 70 days of cultivation. Relative growth rates and the effects of substrates on mycorrhizal formation were calculated after 165 days of cultivation. Germination efficiency and growth indices were best when inoculated OA medium was used. Corncob and pine bark showed the highest percentages of colonized system roots. The OA medium inoculated with Epulorhiza sp. shows potential for C. glutiniferum seedling production. Corncob and pine bark are promising substitutes for tree fern fiber as substrates for the acclimatization of orchid seedlings.

  10. BIOACTIVE COMPOUNDS AND ANTIOXIDANT CAPACITY FROM FIVE TYPES OF SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Florina Maria Copaciu

    2016-10-01

    Full Text Available After germination process, the green seedlings accumulate important quantities of bioactive compounds such as: enzymes, vitamins, minerals, chlorophylls and nutrients. The current study presents a comparison between different bioactive compounds and their antioxidant capacity, after the seedling germination and growth of five seeds (arugula, lentil, wheat, beans and mustard both on soil, in a pot (natural system, and directly on cotton wool soaked, in water (artificial system. In this study the carotenoids content and the antioxidant capacity were analysed. The data of the present study showed that the highest amount of zeaxanthin and β - carotene was found in cultivars of wheat grown in natural system, while the highest antioxidant activity was found in cultivars of wheat, lentils and beans, though in this case with no statistical differences between the systems. The results show statistical differences between the values of bioactive compounds in the five types of seedlings but also in the values obtained for the same seedlings in different systems. The best cultivars for improving the nutritional quality for human consumption are wheat seedlings followed by lentil ones.

  11. Polyphenolic Profile of Maize Seedlings Treated with 24-Epibrassinolide

    Directory of Open Access Journals (Sweden)

    Hadi Waisi

    2015-01-01

    Full Text Available High-performance thin-layer chromatography (HPTLC combined with image analysis and pattern recognition methods were used for fingerprinting of phenolic compounds present in seedlings of two maize genotypes ZP 434 (new generation hybrid, drought tolerant and ZP 704 (older generation hybrid, drought sensitive treated with different concentrations of 24-epibrassinolide. This is the first report of TLC chromatographic profile of phenolics’ mixtures in maize seed extracts influenced by brassinosteroid phytohormones. Nine samples of shoot of seedlings for the whole concentration range of phytohormones (5.2 × 10−7–5.2 × 10−15 M, one sample of root of seedlings treated with 5.2 × 10−15 M 24-epibrassinolide, and the control samples of nontreated seedlings, for both genotypes, were analyzed. Phenolic profiles of root extracts indicate the absence of more polar compounds such as phenolic acids and glycosides present in shoot of seedlings. Also, hormones applied in higher concentrations have an inhibiting effect on the content of phenolics in ZP 434. Application of chemometric methods enables characterization of particular genotype of maize according to its phenolic profile.

  12. Influence of selected Rhizoctonia solani isolates on sugar beet seedlings

    Directory of Open Access Journals (Sweden)

    Skonieczek Paweł

    2016-04-01

    Full Text Available From 2008 to 2010 the levels of sugar beet seedlings infection caused by Rhizoctonia solani were compared in laboratory tests. Seven sugar beet lines were tested: H56, H66, S2, S3, S4, S5 and S6 as well as three control cultivars: Carlos, Esperanza and Janosik. Sugar beet lines with tolerance to rhizoctoniosis and cultivars without tolerance were infected artificially by R. solani isolates: R1, R28a and R28b. These isolates belong to the second anastomosis group (AG, which is usually highly pathogenic to beet roots. The aim of the experiment was to test whether the tolerance of sugar beet genotypes to R. solani AG 2 prevents both root rot, and damping-off of seedlings, induced by the pathogen. Sugar beet lines tolerant to brown root rot in laboratory tests were significantly less sensitive to infection of the seedlings by R. solani AG 2 isolates in comparison to control cultivars. Rhizoctonia solani AG 2 isolates demonstrated considerable differences in pathogenicity against seedlings of sugar beet lines and cultivars. The strongest infection of sugar beet seedlings occurred with the isolate R28b. The greatest tolerance to infection by AG 2 isolates was found for the S5 and S3 breeding lines.

  13. Tebuconazole Regulates Fatty Acid Composition of Etiolated Winter Wheat Seedlings

    Directory of Open Access Journals (Sweden)

    A.V. Korsukova

    2016-05-01

    Full Text Available The fatty acid composition of shoots of unhardened and hardened to cold etiolated winter wheat seedlings grown from seeds treated with tebuconazole-based protectant «Bunker» (content of tebuconazole 60 grams per liter, g/L, and the seedlings frost resistance has been studied. It is shown that treatment of winter wheat seeds by «Bunker» preparation (1,5 microliter per gram of seeds, µl/g is accompanied by an increase of the fatty acids unsaturation in the shoots and increase of the seedlings frost resistance (–8°C, 24 h. The most pronounced decrease in the content of saturated palmitic acid and increase in the content of unsaturated α-linolenic acid were observed during cold hardening of winter wheat seedlings grown from seeds treated by tebuconazole-based protectant. It is concluded that the seeds treatment with tebuconazole-based protectant causes changes of fatty acid composition of winter wheat seedlings to increase their frost resistance.

  14. Windows of opportunity: tresholds to mangrove seedling establishement on tidal flats

    NARCIS (Netherlands)

    Balke, T.; Bouma, T.J.; Horstman, Erik; Webb, E.L.; Erftemeijer, P.L.A.; Herman, P.M.J.

    2011-01-01

    Physical processes limiting colonization of bare tidal flats by pioneer mangrove species have commonly been described but not yet quantified. Understanding thresholds to early seedling establishment is critical for successful restoration and management of mangrove forests. We determined how seedling

  15. Windows of opportunity: thresholds to mangrove seedling establishment on tidal flats

    NARCIS (Netherlands)

    Balke, T.; Bouma, T.J.; Horstman, E.M.; Webb, E.L.; Erftemeijer, P.L.A.; Herman, P.M.J.

    2011-01-01

    Physical processes limiting colonization of bare tidal flats by pioneer mangrove species have commonly been described but not yet quantified. Understanding thresholds to early seedling establishment is critical for successful restoration and management of mangrove forests. We determined how seedling

  16. THE EFFECT OF MAGNETIC LIQUIDS IN SOME TREE SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Ioan Creanga

    2005-08-01

    Full Text Available The seedlings of two tree species, the black poplar hybrid (Populus canadiensis Moench. and the pedunculate oak (Quercus robur L., among the most important for the temperate region, were treated with various concentrations of oil-ferrofluid based on natural hydrocarbons. The experiment has revealed the ferrofluid influence on the assimilatory pigments as well as on the nucleic acids (spectral measurements in young plantlets aged of 3 months. It was found that the levels of assimilatory pigments are generally diminished though the ratio chlorophyll a/chlorophyll b is generally enhanced for ferrofluid samples suggesting the seedlings sensitivity to the chemical and magnetic stimuli consistent with the ferrofuid addition. The LHC II system (Light Harvesting Complex II sensitivity to external factors might be associated with the ferrofluid influence on the young seedlings photosynthesis.

  17. Nitrogen ion utilization by tulip poplar (Liriodendron tulipifera L. ) seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Mann, L.K.

    1982-01-01

    Growth responses of one-year-old tulip poplar seedlings were determined for different nitrogen sources (HN/sub 4/NO/sub 3/, NH+/sub 4/, NO-/sub 3/, no nitrogen) at 336 ppm N in nutrient culture. At the end of three months, there were no significant differences in growth observed among treatments in terms of stem elongation, leaf area, and leaf size. After four months, however, seedlings of the NH/sub 4/NO/sub 3/ treatment exhibited significantly (P<0.05) greater growth (final weight gain and stem elongation) than all other nitrogen sorces. Growth was slightly less for the NO-/sub 3/ treatment plants, but compared with NH+/sub 4/ and no nitrogen treatment, both NH/sub 4/NO/sub 3/ and NO-/sub 3/ treatments exhibited significantly greater growth responses. NO-/sub 3/ is recommended as the sole nitrogen source, especially for small seedlings of tulip poplar.

  18. Seedling establishment of Ferocactus acanthodes in relation to drought

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, P.W.; Nobel, P.S.

    1981-08-01

    The 30 smallest seedlings of Ferocactus acanthodes (Lem.) Britton and Rose (Cactaceae) at a canyon site in the northwestern Sonoran desert averaged 2.5 cm in height. Based on field studies of CO/sub 2/ exchange throughout the year, the estimated time of their germination was late summer 1976. To explan why so little establishment occurred in recent years, the length of lethal drought for seedlings of various ages was calculated from the seedling geometry (volume-to-surface ratio), dehydration tolerance, and transpiration rates. Individual years were identified which had sufficiently long growing seasons relative to the length of the subsequent droughts to allow establishment. Eight of the last 18 y were found to be suitable for establishment of F. acanthodes, the latest year being 1976.

  19. Growth response of Pinus densiflora seedlings inoculated with three indigenous ectomycorrhizal fungi in combination

    OpenAIRE

    Dalong,M; Luhe,W; Guoting,Y; M Liqiang; Chun,L

    2011-01-01

    Pinus densiflora seedlings were inoculated with three indigenous ectomycorrhizal fungi (Cenococcum geophilum, Rhizopogon roseolus and Russula densifolia) in single-, two-, and three-species treatments. After 8 months, the colonization rates of each ectomycorrhizal species, seedling growth and the nutrition were assessed in each treatment. P. densiflora seedlings inoculated with different ECM species composition showed an increase in height and basal diameter and improved seedling root and sho...

  20. Recruitment of a mast-fruiting, bird-dispersed tree: Bridging frugivore activity and seedling establishment

    OpenAIRE

    Herrera, Carlos M.; Jordano, Pedro; López-Soria, L.; Amat, Juan A.

    1994-01-01

    The recruitment of Phillyrea latifolia L. (Oleaceae), a bird-dispersed tree of Mediterranean forest, is described. Fruit removal by birds, seed rain, post-dispersal seed predation, seed germination, and seedling emergence, survival, and establishment were studied. The main objective was testing whether seed dispersal by birds produced a predictable seedling shadow as a result of coupled patterns of seed rain, seedling emergence, and seedling establishment. P. latifolia is a mast-fruiting spec...

  1. Study on the Export Competitiveness of China’s Flower Seedlings

    Institute of Scientific and Technical Information of China (English)

    Jie; ZHOU

    2015-01-01

    This paper introduces the " National Diamond Model" and reviews the literature concerning the export of flower seedlings.Then it analyzes the production and export of Chinese flower seedlings,as well as the factors( factor endowments,foreign demand,related industries and industrial organization) influencing the production of Chinese flower seedlings based on Diamond Model.Finally,this paper puts forth the recommendations for the enhancement of the export competitiveness of Chinese flower seedlings.

  2. Impact of climate change, seedling type and provenance on the risk of damage to Norway spruce (Picea abies (L.) Karst.) seedlings in Sweden due to early summer frosts

    Energy Technology Data Exchange (ETDEWEB)

    Langvall, Ola (Swedish Univ. of Agricultural Sciences, Unit for Field-based Forest Research, Asa Forest Research Station, Lammhult (Sweden))

    2011-04-15

    A model including site-specific microclimate-affecting properties of a forest regeneration area together with seedling characteristics was used to evaluate the accumulated risk of frost damage to Norway spruce (Picea abies (L.) Karst.) seedlings. Climate change in Sweden was simulated on the basis of the regional climate model RCA3. The daily average temperature, the driving factor for bud burst in the model, was adjusted using the difference between the mean of the climate model data for the years 1961-1990 and 2036-2065. The model was run for a highly frost prone, clear-cut site in which bare-rooted Norway spruce seedlings of mid-Swedish provenance were planted. Alternate runs were conducted with data for containerized seedlings and seedlings of Belarusian origin. The study showed that bud burst will occur at earlier dates throughout Sweden in the period 2036-2065 if the climate changes according to either of the climate scenarios examined, compared to the reference period 1961-1990. Furthermore, the risk of damage to Norway spruce seedlings as a result of frost events during summer will increase in southern Sweden and be unaffected or decrease in northern Sweden. The risk of frost damage was exacerbated in containerized seedlings, while the risk was lower for the seedlings of Belarusian provenance when compared with bare-rooted seedlings or seedlings of mid-Swedish origin

  3. Gleditschia amorphoides Taub. SEEDLING GROWTH PRODUCED UNDER DIFFERENT SUBSTRATES

    Directory of Open Access Journals (Sweden)

    Michele Fernanda Bortolini

    2012-03-01

    Full Text Available http://dx.doi.org/10.5902/198050985077Locally known as sucará, Gleditschia amorphoides besides being a woody species, it can be used in plantations used for the rehabilitation of degraded areas. Therefore, the objective of the current work was to evaluate the seedling growth, over time produced under different substrates. The experiment was made at the UNIOESTE nursery in Santa Helena district, in Paraná state, using direct sowing in polypropylene sized tubes of 200cm3. Different mixtures were tested as substrate, containing Plantmax®, decomposed leaves residue, sawdust, litter, cattle manure and carbonized rice hulls. Monthly, during 180 days, evaluations of height and diameter of the lap were made, analyzed by a completely randomized design, with 5 replicates of 12 seedlings, in a subdivided plot scheme in time. At the end of the experiment, root dry mass and aerial part dry mass, the relation between these variables and the leaf area, were determined for 12 seedlings each treatment, in a completely randomized design. The water-holding capacity, substrate total porosity and pH were determined. All data were submitted to variance analysis and the means compared by the Tukey’s test. In general, all substrates provided gradual increase in the diameter of the lap and seedling height. Seedlings produced in 50% of Plantmax®+ 20% of carbonized rice hulls + 30% of cattle manure provided bigger diameter (4,5mm and seedlings height (22,7 cm, as well as bigger root dry mass and aerial part dry mass (0,88 and 1,62g, respectively followed by seedlings produced in 50% of Plantmax®+ 20% of carbonized rice hulls + 20% of cattle manure + 10% leaf residue with 4,0mm and 19,7mm, for diameter and height respectively. In these experimental conditions, Sucará seedlings produced in 50% of Plantmax®+ 20% of carbonized rice hulls + 30% of cattle manure presented bigger growth.

  4. Transport of calcium in seedlings and cuttings of mung bean

    Energy Technology Data Exchange (ETDEWEB)

    Broadbent, W.

    1984-01-01

    At germination, a very small proportion of stored calcium is mobilized to the axis in the absence of exogenous supplies of calcium. There is no evidence for transport in phloem since exported calcium does not enter the seedling root. /sup 45/Calcium is not redistributed when applied to cotyledons at germination of leaves of seedlings. A subsequent large addition of unlabelled calcium promotes a small redistribution from leaves. Triiodobenzoic acid (TIBA), applied to leaves, leads to a small reduction in calcium accumulation but does not effect redistribution. Auxin is without effect and auxin plus TIBA promotes accumulation. These results are discussed in relation to possible extracellular binding sites for calcium.

  5. Common arbuscular mycorrhizal networks amplify competition for phosphorus between seedlings and established plants

    DEFF Research Database (Denmark)

    Merrild, Marie Porret; Ambus, Per; Rosendahl, Søren;

    2013-01-01

    ) seedlings grew into established networks of Rhizophagus irregularis and cucumber (Cucumis sativus) in two experiments. One experiment studied seedling uptake of 32P in the network in response to cutting of cucumber shoots; the other analysed seedling uptake of P and nitrogen (N) in the presence of intact...

  6. Effects of vesicular-arbuscular mycorrhizae and seed source on nursery-grown black walnut seedlings

    Science.gov (United States)

    B. L. Brookshire; H. E. Garrett; T. L. Robison

    2003-01-01

    A nursery study was established in Missouri to evaluate the effects of endomycorrhizal inoculation and seed source on the growth of black walnut seedlings. Inoculation, in general, resulted in seedlings with significantly larger sturdiness quotients. Glomus intraradicies was found to produce larger seedlings than Glomus etunicatus...

  7. Effects of Toxic Levels of Aluminium on Seedling Parameters of Rice under Hydroponic Culture

    Institute of Scientific and Technical Information of China (English)

    Bidhan ROY; Sanjib BHADRA

    2014-01-01

    The presence of Al in the rhizosphere of rice in acid soil restricts root growth and significantly reduces crop productivity. In this study, the effects of Al (30, 60 and 90 µg/mL) on seedling root growth, number of primary roots per seedling, seedling shoot length, number of leaves per seedling, seedling fresh weight, and seedling dry weight were studied. Rice genotypes were classified into three different classes, namely, tolerant, moderately tolerant, and susceptible, based on root tolerance index. The method of hydroponic culture was modified, and elaborated in the text. Toxic levels of Al in nutrient solution significantly decreased seedling root growth, number of primary roots, seedling shoot length, number of leaves per seedling, seedling fresh weight, and seedling dry weight. Few genotypes showed longer root length at 30 µg/mL Al in nutrient solutions compared with the control. High levels of Al in nutrient solutions were highly toxic for rice seedlings. Based on root tolerance index, Radhunipagal, Gobindobhog, Badshabhog, Kalobhog, UBKVR-11, UBKVR-16, UBKVR-18, Khasha and IVT4007-B were classified as tolerant genotypes, and these genotypes may be used as donors for breeding of Al-toxicity tolerance.

  8. Growth and water relations of seedlings of two subspecies of Eucalyptus globulus.

    Science.gov (United States)

    Wang, D; Bachelard, E P; Banks, J C

    1988-06-01

    Seedlings of Eucalyptus globulus Labill subsp. globulus grown in soil in pots in the greenhouse grew faster than seedlings of E. globulus subsp. bicostata, and responded better to added nutrients and water. However, water stress caused a greater reduction in the growth of shoots and roots, and in the root/shoot ratios of fertilized seedlings of subsp. globulus than in those of bicostata. More leaf surface wax was produced by seedlings grown in the presence of fertilizer and an adequate supply of water than by seedlings subjected to nutrient or water stress. Despite larger amounts of leaf surface wax, seedlings of subsp. bicostata had higher epidermal conductances than seedlings of subspecies globulus. However, epidermal conductances were reduced more by water stress and by fertilization in seedlings of subsp. bicostata than in subsp. globulus. Tissue osmotic potentials at full and zero turgor were reduced by water stress only in seedlings of subsp. bicostata and were increased by fertilizer only in seedlings of subsp. globulus. The results indicate that although seedlings of subsp. globulus have inherently higher growth rates, seedlings of subsp. bicostata are better adapted to drought.

  9. Comparative growth of black spruce container seedlings grown in worm-casting-amended soilless media

    Energy Technology Data Exchange (ETDEWEB)

    Menes, P.A.; Colombo, S.J.

    1992-01-01

    This study compared the morphology of containerized black spruce seedlings grown in fertilized and non-fertilized worm- casting-amended media to seedlings grown in a non-amended fertilized peat-vermiculite mix. The comparison was made to determine if various media amended with castings could produce seedlings equivalent to those produced using a standard nursery growing medium.

  10. INFLUENCE OF A PERIOD OF ARTIFICIAL LIGHTING ON FORMATION OF LETTUCE SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Abyan M. V.

    2014-09-01

    Full Text Available The article presents a research of reaction of seedlings of lettuce on light duration with sodium lamps when grown in a greenhouse. It was shown that in winter conditions of the Krasnodar Region the intensity of natural light to produce quality seedlings of lettuce is insufficient and additional lighting has a significant influence on the morphology of lettuce seedlings

  11. Antioxidants and anti-stress compounds improve the survival of cryopreserved Arabidopsis seedlings

    Science.gov (United States)

    Cryopreservation is a safe and cost-effective tool for the long-term storage of plant germplasm. Successful cryopreservation depends on suitable cryoprotection protocol. In Arabidopsis seedlings cryopreservation, the growth ability could be partly restored in 60-h seedlings, whereas 72-h seedlings d...

  12. Four different Phytophthora species that are able to infect Scots pine seedlings in laboratory conditions

    Directory of Open Access Journals (Sweden)

    Tkaczyk Miłosz

    2016-09-01

    Full Text Available To investigate susceptibility of young Scots pine seedlings to four Phytophthora species: Phytophthora cactorum, Phytophthora cambivora, Phytophthora plurivora and Phytophthora pini; seven-day-old seedlings of Scots pine (15 seedlings per experiment were infected using agar plugs of the respective species. Control group also consisted of 15 seedlings and was inoculated with sterile agar plugs. Results unambiguously show that after 4.5 days, all seedlings show clear signs of infection and display severe symptoms of tissue damage and necrosis. Moreover, three and two seedlings in the P. cactorum and P. cambivora infected seedlings groups, respectively, collapsed. The length of largest necrosis measured 13.4±3.90 mm and was caused by P. cactorum. To rule out any putative contamination or infection by secondary pathogens, re-isolations of pathogens from infection sites were performed and were positive in 100% of plated pieces of infected seedlings. All re-isolations were, however, negative in the case of the control group. Detailed microscopic analyses of infected tissues of young seedlings confirmed the presence of numerous Phytophthora species inside and on the surface of infected seedlings. Therefore, our results suggest Phytophthora spp. and mainly P. cactorum and P. cambivora as aggressive pathogens of Scots pine seedlings and highlight a putative involvement of these species in the damping off of young Scots pine seedlings frequently observed in forest nurseries.

  13. Mycorrhizal inoculation of pecan seedlings with some marketable truffles

    Directory of Open Access Journals (Sweden)

    Gian M. Benucci

    2013-12-01

    Full Text Available Pecan is the common name of Carya illinoinensis (Wangenh. K. Koch, an ectomycorrhizal tree native to North America, also frequently known as hickory. Mycorrhizal inoculations of pecan seedlings with: Tuber aestivum Vittad., T. borchii Vittad., T. indicum Cooke & Massee, and T. lyonii Butters are described and discussed.

  14. Sewage sludge as substrate for Tectona grandis L. seedlings production

    Directory of Open Access Journals (Sweden)

    Daniele Rodrigues Gomes

    2013-03-01

    Full Text Available The sewage sludge is a waste from sewage treatment plants, which can be used in formulations of substrates for seedling production. This study aimed to evaluate the effects of different proportions of sewage sludge, soil and commercial substrate on the growth characteristics of Tectona grandis seedlings in tubes of 120 cm³ volume capacity. The sewage sludge used came from the STP's Cachoeiro de Itapemirim / ES. The seedlings were grown in the forest nursery / CCA / UFES. The statistical design used in the experiment was completely randomized design (CRD with six treatments and five replications. The treatments constituted of sewage sludge : commercial substrate: soil (v: v: v, which corresponded to 20:70:10 (T1, 40:50:10 (T2, 60:30:10 (T3, 80 : 10:10 (T4, 90:0:10 (T5 and the control treatment with 0:90:10 (T6. All variables assessed were significant at the 5% level of probability. The control (T6 showed results statistically equal to or lower than the treatments T3 with 60% of sewage sludge concentration (T3. It follows then that the use of sewage sludge in seedling production is feasible and promising, however, used in a proper proportion.

  15. [Characterization of growth-promoting rhizobacteria in Eucalyptus nitens seedlings].

    Science.gov (United States)

    Angulo, Violeta C; Sanfuentes, Eugenio A; Rodríguez, Francisco; Sossa, Katherine E

    2014-01-01

    Rhizospheric and endophytic bacteria were isolated from the rizosphere and root tissue of Eucalyptus nitens. The objective of this work was to evaluate their capacity to promote growth in seedlings of the same species under greenhouse conditions. The isolates that improved seedling growth were identified and characterized by their capacity to produce indoleacetic acid (IAA), solubilize phosphates and increase 1-aminocyclopropane-1-carboxylate (ACC) deaminase activity. One hundred and five morphologically different strains were isolated, 15 of which promoted E. nitens seedling growth, significantly increasing the height (50%), root length (45%) as well as the aerial and root dry weight (142% and 135% respectively) of the plants. Bacteria belonged to the genus Arthrobacter, Lysinibacillus, Rahnella and Bacillus. Isolates A. phenanthrenivorans 21 and B. cereus 113 improved 3.15 times the emergence of E. nitens after 12 days, compared to control samples. Among isolated R. aquatilis, 78 showed the highest production of IAA (97.5±2.87 μg/ml) in the presence of tryptophan and the highest solubilizer index (2.4) for phosphorus, while B. amyloliquefaciens 60 isolate was positive for ACC deaminase activity. Our results reveal the potential of the studied rhizobacteria as promoters of emergence and seedling growth of E. nitens, and their possible use as PGPR inoculants, since they have more than one mechanism associated with plant growth promotion.

  16. Starch bioengineering affects cereal grain germination and seedling establishment

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...

  17. Measuring Tree Seedlings and Associated Understory Vegetation in Pennsylvania's Forests

    Science.gov (United States)

    William H. McWilliams; Todd W. Bowersox; Patrick H. Brose; Daniel A. Devlin; James C. Finley; Kurt W. Gottschalk; Steve Horsley; Susan L. King; Brian M. LaPoint; Tonya W. Lister; Larry H. McCormick; Gary W. Miller; Charles T. Scott; Harry Steele; Kim C. Steiner; Susan L. Stout; James A. Westfall; Robert L. White

    2005-01-01

    The Northeastern Research Station's Forest Inventory and Analysis (NE-FIA) unit is conducting the Pennsylvania Regeneration Study (PRS) to evaluate composition and abundance of tree seedlings and associated vegetation. Sampling methods for the PRS were tested and developed in a pilot study to determine the appropriate number of 2-m microplots needed to capture...

  18. MARVIN : high speed 3D imaging for seedling classification

    NARCIS (Netherlands)

    Koenderink, N.J.J.P.; Wigham, M.L.I.; Golbach, F.B.T.F.; Otten, G.W.; Gerlich, R.J.H.; Zedde, van de H.J.

    2009-01-01

    The next generation of automated sorting machines for seedlings demands 3D models of the plants to be made at high speed and with high accuracy. In our system the 3D plant model is created based on the information of 24 RGB cameras. Our contribution is an image acquisition technique based on

  19. Phosphine-induced physiological and biochemical responses in rice seedlings.

    Science.gov (United States)

    Mi, Lina; Niu, Xiaojun; Lu, Meiqing; Ma, Jinling; Wu, Jiandong; Zhou, Xingqiu

    2014-04-01

    Paddy fields have been demonstrated to be one of the major resources of atmospheric phosphine and may have both positive and negative effects on rice plants. To elucidate the physiological and biochemical responses of rice plants to phosphine, rice seedlings (30 d old) were selected as a model plant and were treated with different concentrations of phosphine (0, 1.4, 4.2, and 7.0 mg m(-3)). Antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and lipid peroxidation measured via malondialdehyde (MDA) were determined as indicators of the physiological and biochemical responses of the rice seedlings to phosphine exposure. Increasing concentrations of phosphine treatment enhanced the activity of SOD, POD, and CAT. In addition, the MDA content increased with increasing concentrations of phosphine. These results suggested that antioxidant enzymes played important roles in protecting rice seedlings from ROS damage. Moreover, rice seedlings were able to cope with the oxidative stress induced by low concentrations of phosphine via an increase in antioxidant enzymatic activities. However, oxidative stress may not fully be prevented when the plants were exposed to higher concentrations of phosphine.

  20. The effect of ectomycorrhizal fungi and bacteria on pine seedlings

    Directory of Open Access Journals (Sweden)

    Hanna Dahm

    2014-08-01

    Full Text Available The effect of ecomycorrhizal fungi (Hebelon crustuliniforme(Bull.: Fr. Quél. 5392 and Pisolithus tinctorius (Pers. Coker et Couch 5335 and bacteria (Bacillus polymyxa and Azospirillum brasilense. associated with mycorrhizas on the growth of pine seedligs was investigated. In addition the influence of bacteria on fungal biomass production and the relationship between ectomycorrhizal fungi and fungi pathogenic to root of pine seedlings were determined. In general, the shoot/root ratio was higher in plants inoculated with Hebeloma crustuliniforme and bacteria than in the control seedlings (grown only under sterile conditions. In non-sterile substrate the root/shoot ratio of the mycorrhizal seedlings was lower as compared to the control. Similar phenomenon was noted in plants inoculated with the mycorrhizal fungus Pisolithus tinetorius. The bacteria used as well as the time of introduction of these organisms into the cultures of mycorrhiza fungi affected the production of fungal biomass. Hebeloma crustuliniforme and Pisolithus tinctorius inhibited the growth of Rizoctonia solani and Fusarium oxysporum fungi pathogenic to pine seedlings.

  1. Photosynthetic efficiency of Pedunculate oak seedlings under simulated water stress

    Directory of Open Access Journals (Sweden)

    Popović Zorica

    2010-01-01

    Full Text Available Photosynthetic performance of seedlings of Quercus robur exposed to short-term water stress in the laboratory conditions was assessed through the method of induced fluorometry. The substrate for seedlings was clayey loam, with the dominant texture fraction made of silt, followed by clay and fine sand, with total porosity 68.2%. Seedlings were separated in two groups: control (C (soil water regime in pots was maintained at the level of field water capacity and treated (water-stressed, WS (soil water regime was maintained in the range of wilting point and lentocapillary capacity. The photosynthetic efficiency was 0.642±0.25 and 0.522±0.024 (WS and C, respectively, which was mostly due to transplantation disturbances and sporadic leaf chlorosis. During the experiment Fv/Fm decreased in both groups (0.551±0.0100 and 0.427±0.018 in C and WS, respectively. Our results showed significant differences between stressed and control group, in regard to both observed parameters (Fv/Fm and T½. Photosynthetic efficiency of pedunculate oak seedlings was significantly affected by short-term water stress, but to a lesser extent than by sufficient watering.

  2. Measuring Maize Seedling Drought Response in Search of Tolerant Germplasm

    Directory of Open Access Journals (Sweden)

    Dirk Hays

    2013-02-01

    Full Text Available To identify and develop drought tolerant maize (Zea mays L., high-throughput and cost-effective screening methods are needed. In dicot crops, measuring survival and recovery of seedlings has been successful in predicting drought tolerance but has not been reported in C4 grasses such as maize. Seedlings of sixty-two diverse maize inbred lines and their hybrid testcross progeny were evaluated for germination, survival and recovery after a series of drought cycles. Genotypic differences among inbred lines and hybrid testcrosses were best explained approximately 13 and 18 days after planting, respectively. Genotypic effects were significant and explained over 6% of experimental variance. Specifically three inbred lines had significant survival, and 14 hybrids had significant recovery. However, no significant correlation was observed between hybrids and inbreds (R2 = 0.03, indicating seedling stress response is more useful as a secondary screening parameter in hybrids than in inbred lines per se. Field yield data under full and limited irrigation indicated that seedling drought mechanisms were independent of drought responses at flowering in this study.

  3. Soybean seedlings tolerate abrasion from air-propelled grit

    Science.gov (United States)

    New tools for controlling weeds would be useful for soybean production in organic systems. Air-propelled abrasive grit is one such tool that performs well for in-row weed control in corn, but crop safety in soybean is unknown. We examined responses to abrasion by corn-cob grit of soybean seedlings a...

  4. Optimal light for greenhouse culture of American ginseng seedlings

    Directory of Open Access Journals (Sweden)

    John T.A. Proctor

    2017-07-01

    Full Text Available Three greenhouse experiments with American ginseng seedlings growing under light levels from 4.8% to 68% showed a quadratic response for root dry weight, giving an optimal root dry weight of 239 mg (range 160–415 mg at an optimal light level of 35.6% (range 30.6–43.2%.

  5. Sugar signalling during germination and early seedling establishment in Arabidopsis

    NARCIS (Netherlands)

    Dekkers, S.J.W.

    2006-01-01

    Sugars have pronounced effects on many plant processes like gene expression, germination and early seedling development. Several screens for sugar insensitive mutants were performed to identify genes involved in sugar response pathways using the model plant Arabidopsis. These include sun, gin and si

  6. Identification of seedling cabbages and weeds using hyperspectral imaging

    Science.gov (United States)

    Target detectionis one of research focues for precision chemical application. This study developed a method to identify seedling cabbages and weeds using hyperspectral spectral imaging. In processing the image data, with ENVI software, after dimension reduction, noise reduction, de-correlation for h...

  7. Growth and Mineral Composition of Passion Fruit Seedlings

    Directory of Open Access Journals (Sweden)

    Edson Batista Lopes

    2010-06-01

    Full Text Available The aim of this study was to evaluate the growth and mineral composition of the yellow passion fruit plant seedlings (Passiflora edulis Sims f. flavicarpa Degener in fertilized substrates with boron and kalium, with and without coconut fiber (25 % e 0% and bovine manure (15%. The treatments were distributed in a outlined random block with four blocks and four seedlings per portion being five kalium doses and five boron doses combined according to the main Composite Central of Box. Each 20 days were done evaluations. Were analyzed the dry and green matter of the root and the leaf, foliated area and nutriment contents of the leaf. The results were submitted to analysis of change and regression. There was no significant effect of the treatments on the seedling's height, diameter of the shaft, number of leaves and foliated area. The coconut fiber doesn’t affect their growth and mineral composition. The kalium increased in a lineal way the root growth and aerial part of the seedlings, either the foliar contents of kalium, but reduce magnesium proportions. The boron increased the foliar contents of boron and reduced the nitrogen’s.

  8. Proteome Profiling of Paulownia Seedlings Infected with Phytoplasma

    Science.gov (United States)

    Cao, Xibing; Fan, Guoqiang; Dong, Yanpeng; Zhao, Zhenli; Deng, Minjie; Wang, Zhe; Liu, Wenshan

    2017-01-01

    Phytoplasma is an insect-transmitted pathogen that causes witches' broom disease in many plants. Paulownia witches' broom is one of the most destructive diseases threatening Paulownia production. The molecular mechanisms associated with this disease have been investigated by transcriptome sequencing, but changes in protein abundance have not been investigated with isobaric tags for relative and absolute quantitation. Previous results have shown that methyl methane sulfonate (MMS) can help Paulownia seedlings recover from the symptoms of witches' broom and reinstate a healthy morphology. In this study, a transcriptomic-assisted proteomic technique was used to analyze the protein changes in phytoplasma-infected Paulownia tomentosa seedlings, phytoplasma-infected seedlings treated with 20 and 60 mg·L−1 MMS, and healthy seedlings. A total of 2,051 proteins were obtained, 879 of which were found to be differentially abundant in pairwise comparisons between the sample groups. Among the differentially abundant proteins, 43 were related to Paulownia witches' broom disease and many of them were annotated to be involved in photosynthesis, expression of dwarf symptom, energy production, and cell signal pathways. PMID:28344590

  9. Inhibitory effects of monoterpenes on seed germination and seedling growth.

    Science.gov (United States)

    Kordali, Saban; Cakir, Ahmet; Sutay, Sunay

    2007-01-01

    Monoterpenes, the chemical constituents of essential oils found in plants, are known biologically active compounds. The present study was conducted to investigate the inhibitory effects of 30 monoterpenes including monoterpene hydrocarbons and oxygenated monoterpenes on seed germination and seedling growth of Amaranthus retroflexus, Chenopodium album and Rumex crispus under laboratory conditions. The monoterpenes were applied at contents of 10 and 20 microl for liquid compounds and 10 and 20 microg for solid compounds. The results show that most of the monoterpenes significantly inhibited seed germination and seedling growth of the tested plants. Oxygenated monoterpenes including beta-citronellol, nerol and terpinen-4-ol completely inhibited seed germination and seedling growth of all tested plants. Their inhibitory effects were also stronger than that of the herbicide 2,4-D. In general, monoterpenes were less effective against seed germination and seedling growth of C. album as compared with R. crispus and A. retroflexus. Phytotoxic effects of monoterpene hydrocarbons were found to be lower than those of oxygenated monoterpenes. The alcohol derivatives of oxygenated monoterpenes were also found to be more phytotoxic as compared with their acetate derivatives. Based on the present results, it can be concluded that the oxygenated monoterpenes can be used as potential bio-herbicides.

  10. No de novo sulforaphane biosynthesis in broccoli seedlings

    NARCIS (Netherlands)

    Gorissen, Antonie; Kraut, Nicolai U.; de Visser, Ries; de Vries, Marcel; Roelofsen, Han; Vonk, Roel J.

    2011-01-01

    The isothiocyanate sulforaphane, present in significant amounts in broccoli (Brassica oleracea L.) seedlings in the form of its precursor glucoraphanin, has been identified as an inducer of quinine reductase, a phase-II detoxification enzyme known for its anticarcinogenic properties. Its

  11. Growth promotion mediated by endophytic fungi in cloned seedlings ...

    African Journals Online (AJOL)

    Elohor Owebor

    2016-11-30

    Nov 30, 2016 ... promote plant growth and productivity (Chang et al., .... software Sigma Scan Pro- V.S. O, Jandel Scientific. The quarterly values for stem length and stem diameter were used to determine the percentage growth increase of the seedlings ... values were obtained after six days of drying in a forced air oven at.

  12. Phototropism in seedlings of sunflower, Helianthus annuus L.

    NARCIS (Netherlands)

    Franssen, J.M.

    1980-01-01

    In this thesis the phototropic bending of hypocotyls of sunflower seedlings, Helianthus annuus L., is investigated.

    Chapter 1 gives the reasons for this project. Although phototropism has been studied extensively over the past 100 years, the understanding of

  13. Response of Raphia (Raphia Hookeri) Palm Seedlings to Fertilizer ...

    African Journals Online (AJOL)

    2012r

    2014-11-17

    Nov 17, 2014 ... Key words: Nursery, fertilizer application, Raphia hookeri seedling, dry ... holder farms is the fundamental root causes of declining per capital food ... requirements of plants and the nutrient reserves in the soils is essential for ... A good fertilizer management programme is important to achieve good soil.

  14. Effect of trace elements on growth of Pinus tabulaeformis seedling

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The stimulative effect of trace elements on seed germination and seedling growth of Pinus tabulaeformis was tested. The experiments were carried out on seed soak and topdressing with different trace elements and varied concentrat ions at the nursery of Gardens Research Institute, Harbin, in 2000-2001. The experimental results showed that soaking seed with 1% and 0.2% concentrations of Mn element produced best result for seed germination, and the germination rate was increased by 9%~19% for the seeds treated with 1% concentration and 12%~14% for the seeds treated with 0.2% concentration compared with the control group. The seeds treated with boron element had lowest germination rate. For trace element topdressing, Mn and Mo elements presented good result for seedling growth and th e treatment with low concentration was even better. The height or chlorophyll co ntent of the seedlings with spray of low-concentration Mn and Mo element was muc h higher than that of untreated ones. In the contrast to the treating method of seed soak, topdressing (application of spraying on foliage) had evident effect o n seedling growth.

  15. Sesinoside, a new iridoid glucoside from sesame (Sesamum indicum) seedlings.

    Science.gov (United States)

    Takase, Ryo; Hasegawa, Tsuyoshi; Yamada, Kosumi; Hasegawa, Koji; Shigemori, Hideyuki

    2014-11-01

    A new iridoid glucoside, sesinoside (1), was isolated from the seedlings of Sesamum indicum. The structure of 1 was elucidated by spectroscopic analyses and by methanolysis of 1, which produced the known compounds, phlorigidosides C (2) and (6Z)-foliamenthic acid methyl ester (3). This is the first report of an iridoid glucoside with 3.

  16. Flood tolerance of oak seedlings from bottomland and upland sites

    Science.gov (United States)

    Michael P. Walsh; Jerry Van Sambeek; Mark Coggeshall; David. Gwaze

    2009-01-01

    Artificial regeneration of oak species in floodplains presents numerous challenges because of the seasonal flooding associated with these areas. Utilizing not only flood-tolerant oak species, but also flood tolerant seed sources of the oak species, may serve to enhance seedling survival and growth rates. Despite the importance of these factors to hardwood forest...

  17. Phototropism in seedlings of sunflower, Helianthus annuus L

    NARCIS (Netherlands)

    Franssen, J.M.

    1980-01-01

    In this thesis the phototropic bending of hypocotyls of sunflower seedlings, Helianthus annuus L., is investigated.Chapter 1 gives the reasons for this project. Although phototropism has been studied extensively over the past 100 years, the understanding of the mechanism is far from clear. During th

  18. Establishing northern red oak on a degraded upland site in northeastern Pennsylvania: Influence of seedling pedigree and quality

    Science.gov (United States)

    Cornelia C. Pinchot; Thomas J. Hall; Scott E. Schlarbaum; Arnold M. Saxton; James. Bailey

    2017-01-01

    Enrichment plantings using large oak seedlings of regional sources may promote superior survival and growth compared to direct seeding or standard nursery seedling material. This study evaluated the survival and growth of planted 1-0 northern red oak (Quercus rubra L.) seedlings among 11 families and 3 seedling size classes (small, average, and...

  19. Neighborhood and community interactions determine the spatial pattern of tropical tree seedling survival.

    Science.gov (United States)

    Queenborough, Simon A; Burslem, David F R P; Garwood, Nancy C; Valencia, Renato

    2007-09-01

    Factors affecting survival and recruitment of 3531 individually mapped seedlings of Myristicaceae were examined over three years in a highly diverse neotropical rain forest, at spatial scales of 1-9 m and 25 ha. We found convincing evidence of a community compensatory trend (CCT) in seedling survival (i.e., more abundant species had higher seedling mortality at the 25-ha scale), which suggests that density-dependent mortality may contribute to the spatial dynamics of seedling recruitment. Unlike previous studies, we demonstrate that the CCT was not caused by differences in microhabitat preferences or life history strategy among the study species. In local neighborhood analyses, the spatial autocorrelation of seedling survival was important at small spatial scales (1-5 m) but decayed rapidly with increasing distance. Relative seedling height had the greatest effect on seedling survival. Conspecific seedling density had a more negative effect on survival than heterospecific seedling density and was stronger and extended farther in rare species than in common species. Taken together, the CCT and neighborhood analyses suggest that seedling mortality is coupled more strongly to the landscape-scale abundance of conspecific large trees in common species and the local density of conspecific seedlings in rare species. We conclude that negative density dependence could promote species coexistence in this rain forest community but that the scale dependence of interactions differs between rare and common species.

  20. First year survival of barefoot and containerized hardwood tree seedlings planted in northeast Texas lignite minesoils

    Energy Technology Data Exchange (ETDEWEB)

    Wood, J.; Denman, J. [Texas Utilities Mining Company, Mt. Pleasant, TX (United States); Waxler, M.; Huber, D.A. [Weyerhaeuser, Hot Springs, AK (United States)

    1997-12-31

    Successful regeneration of hardwood tree seedlings is critical to the reclamation of quality wildlife habitat and commercial forests on lignite mines in northeast Texas. Because bareroot hardwood seedlings survival rates have often been lower than desired, the survival of containerized and bareroot hardwood tree seedlings was compared. Seven hardwood species, including six species of oaks, were planted in lignite minesoils on sites classified as bottomland, slope and upland. Three species were planted per site. Containerized seedlings were planted during the fall and winter, whereas bareroot seedlings were planted in the winter only. Survival was determined at the end of the first growing season. Results across all sites indicate that winter-planted containerized seedlings (74%) or bareroot seedlings (76%). Within the sites, the only significant difference was on upland sites where survival of winter-planted containerized seedlings (60%) was lower than bareroot seedlings (77%). Survival among species was not significantly different. There was no significant survival benefit from using more expensive containerized hardwood seedlings. The results also question the practice of planting containerized hardwood seedlings during the typical winter planting season for optimum survival.

  1. Biological seed priming mitigates the effects of water stress in sunflower seedlings.

    Science.gov (United States)

    Singh, Narsingh Bahadur; Singh, Deepmala; Singh, Amit

    2015-04-01

    The sunflower (Helianthus annuus L. cv. PAC 36) seedlings were inoculated with plant growth promoting rhizobacteria (PGPR), viz. Azotobacter chroococcum (A+), Bacillus polymyxa (B+), separately and in combination of the two (AB+). Relative water content and seedling growth were maximum in AB+ seedlings under control. Water stress significantly decreased the RWC, growth and dry mass of non-inoculated seedlings. However, inoculated seedlings maintained higher growth even under water stress. Pigments and protein contents decreased under water stress, but higher amount of the same was observed in stressed AB+ seedlings. Enhanced activity of nitrate reductase was recorded in AB+ seedlings with maximum in control. Water stress significantly decreased the nitrate reductase activity. A significant increase in the activity of superoxide dismutase (SOD) in leaves was recorded under water stress except in B+ with maximum increase in non-inoculated seedlings. Catalase (CAT) activity decreased in stressed non-inoculated seedlings while increased in the leaves of A+ and AB+ seedlings. Almost similar trends were recorded for both leaves and cotyledons. PGPR improved the water status in stressed seedlings and thereby physiological and biochemical parameters and thus ameliorated the severe effects of water stress.

  2. Effects of seed traits variation on seedling performance of the invasive weed, Ambrosia artemisiifolia L.

    Science.gov (United States)

    Ortmans, William; Mahy, Grégory; Monty, Arnaud

    2016-02-01

    Seedling performance can determine the survival of a juvenile plant and impact adult plant performance. Understanding the factors that may impact seedling performance is thus critical, especially for annuals, opportunists or invasive plant species. Seedling performance can vary among mothers or populations in response to environmental conditions or under the influence of seed traits. However, very few studies have investigated seed traits variations and their consequences on seedling performance. Specifically, the following questions have been addressed by this work: 1) How the seed traits of the invasive Ambrosia artemisiifolia L. vary among mothers and populations, as well as along the latitude; 2) How do seed traits influence seedling performance; 3) Is the influence on seedlings temperature dependent. With seeds from nine Western Europe ruderal populations, seed traits that can influence seedling development were measured. The seeds were sown into growth chambers with warmer or colder temperature treatments. During seedling growth, performance-related traits were measured. A high variability in seed traits was highlighted. Variation was determined by the mother identity and population, but not latitude. Together, the temperature, population and the identity of the mother had an effect on seedling performance. Seed traits had a relative impact on seedling performance, but this did not appear to be temperature dependent. Seedling performance exhibited a strong plastic response to the temperature, was shaped by the identity of the mother and the population, and was influenced by a number of seed traits.

  3. Influence of ozone on cold acclimation in sugar maple seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Bertrand, A. [Agriculture and Agri-Food Canada, Sainte-Foy, PQ (Canada) Research Station; Robitaille, G. [Natural Resources Canada, Ste. Foy, PQ (Canada) Canadian Forest Service; Nadeau, P.; Castonguay, Y. [Agriculture and Agri-Food Canada, Sainte-Foy, PQ (Canada) Research Station

    1999-07-01

    A study was carried out with the aim of determining: a) if exposure to ozone gas induces changes in the key parts of cold acclimation in maple seedlings; and b) if the putative changes effect the process of cold acclimation. Two year old seedlings were exposed to two concentrations of ozone, ambient ozone (low ozone), and threefold ambient ozone concentrations (high ozone) from June to September. During the fall, winter and spring, the seedlings were left outdoors to acclimate to natural winter conditions. The freezing tolerance of stems and root tissues was determined for high ozone and low ozone treated seedlings over the winter period. Concomitant determination of the concentrations of starch, sucrose, raffinose, and stachyose in the sugar maple roots as well as ABA concentration in the xylem sap were carried out to assess the molecular changes associated with the cold acclimation of seedlings in the two treatments. Exposure to high concentrations of ozone did not decrease the freezing tolerance of sugar maple roots and improved the freezing tolerance of the stems in the fall. During the period of cold acclimation, an eightfold increase in sucrose concentration occurred in roots and stems, while starch concentration decreased. In roots, the accumulation of soluble sugars coincided with the period of lowest soil temperature. This showed that temperature has a major influence on the amount of sugar formed and the degree of freezing tolerance. There were no ozone treatment effects on either starch hydrolysis or sucrose accumulation in roots. Sucrose is a membrane and protein stabilizer during winter drying. In roots, the concentrations of the galactose containing oligosaccharides, raffinose and stachyose, were higher in the high ozone treatment than in the low ozone treatment, and stachyose indicated a similar response in stems. There is a relation between the increase in ABA concentration and cold acclimation in the sugar maple. 29 refs., 7 figs.

  4. Effects of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species.

    Science.gov (United States)

    Caglar, S; Akgun, A

    2006-07-01

    The experiment was undertaken to test the efficiency of inoculation of vesicular-arbuscular mycorrhizal (VAM) fungi on the seedling growth of three Pistacia species used as rootstocks. The stratified Pistacia seeds were inoculated with VAM fungi. The highest rate of inoculated roots was 96.7% in P. khinjuck seedlings with G. clarum and G. etunicatum, 83.3% in P. vera seedlings with G. caledonium and 73.3% in P. terebinthus seedlings with G. caledonium. Mycorrhizal inoculations improved seedling height only in P. terebinthus. Certain mycorrhizal inoculations increased the leaf N, but not P and K contents. Seedlings inoculated with G. caledonium had higher reducing sugar contents. It was concluded that pre-inoculated Pistacia seedlings could have a better growth in the harsh field conditions.

  5. [Effects of gap size on seedling natural regeneration in artificial Pinus tabulaeformis plantation].

    Science.gov (United States)

    Han, Wen-Juan; Yuan, Xiao-Qing; Zhang, Wen-Hui

    2012-11-01

    To clarify the effects of gap size created by thinning on the seedling natural regeneration in artificial Pinus tabulaeformis plantation, a plot investigation was conducted to study the ecological factors and the age structure, height, diameter, length of needles, and dry biomass of roots, stems, and needles of 1-10 year-old seedlings in different habitats, and a path analysis was made on the environmental factors affecting the seedling regeneration. Obvious differences were observed in the ecological factors in different size gaps and slope aspects. There lacked of above 3 year-old seedlings in understory and of above 7 year-old seedlings in small gap, and the seedlings of 5 and 6 year-old were lesser in big gap. The 1-10 year-old seedlings could be divided into 3 development phases, i. e. , 1-3 year-old, 4-7 year-old, and 8-10 year-old seedlings, among which, 1-3 year-old seedlings were critical for the establishment and growth of the population. The growth situation of the seedlings in different habitats was in order of big gap in shady slope > big gap in sunny slope > small gap in sunny slope > small gap in shady slope > understory in sunny slope > understory in shady slope. Path analysis showed light intensity had decisive positive effects on the seedling number of different development phases, shrub coverage had decisive negative effects on the seedling number of 4-7 year-old and 8-10 year-old phases, whereas humus dry mass had negative effects on the seedling number of 4-7 year-old but positive effects on the seedling number of 8-10 year-old. It was suggested that in the management of artificial P. tabulaeformis plantation, relatively high intensity thinning combined with shrub clearing should be adopted to provide favorable conditions for the sustainable development of P. tabulaeformis population.

  6. A rapid and robust method of identifying transformed Arabidopsis thaliana seedlings following floral dip transformation

    Directory of Open Access Journals (Sweden)

    Gray John C

    2006-11-01

    Full Text Available Abstract Background The floral dip method of transformation by immersion of inflorescences in a suspension of Agrobacterium is the method of choice for Arabidopsis transformation. The presence of a marker, usually antibiotic- or herbicide-resistance, allows identification of transformed seedlings from untransformed seedlings. Seedling selection is a lengthy process which does not always lead to easily identifiable transformants. Selection for kanamycin-, phosphinothricin- and hygromycin B-resistance commonly takes 7–10 d and high seedling density and fungal contamination may result in failure to recover transformants. Results A method for identifying transformed seedlings in as little as 3.25 d has been developed. Arabidopsis T1 seeds obtained after floral dip transformation are plated on 1% agar containing MS medium and kanamycin, phosphinothricin or hygromycin B, as appropriate. After a 2-d stratification period, seeds are subjected to a regime of 4–6 h light, 48 h dark and 24 h light (3.25 d. Kanamycin-resistant and phosphinothricin-resistant seedlings are easily distinguished from non-resistant seedlings by green expanded cotyledons whereas non-resistant seedlings have pale unexpanded cotyledons. Seedlings grown on hygromycin B differ from those grown on kanamycin and phosphinothricin as both resistant and non-resistant seedlings are green. However, hygromycin B-resistant seedlings are easily identified as they have long hypocotyls (0.8–1.0 cm whereas non-resistant seedlings have short hypocotyls (0.2–0.4 cm. Conclusion The method presented here is an improvement on current selection methods as it allows quicker identification of transformed seedlings: transformed seedlings are easily discernable from non-transformants in as little as 3.25 d in comparison to the 7–10 d required for selection using current protocols.

  7. Relationships between established seedling survival and growth in evergreen broad-leaved forest in Tiantong

    Directory of Open Access Journals (Sweden)

    Heming Liu

    2017-01-01

    Full Text Available Community seedling regeneration is a crucial process for maintaining species coexistence. The stage from which an established seedling becomes a new reproductive individual is one of the most important components of community regeneration, and influences the community recruitment pattern. However, the short-term mortality of established seedlings is lower than newly germinated seedlings, and previous studies have not been able to analyze the effect of biotic neighborhoods and abiotic micro-habitat factors on established seedling survival perfectly. Therefore, we suggest that the growth status of established seedlings could predict established seedling survival during development, and analyze the effects of these biotic and abiotic factors on established seedling growth, in order to indirectly estimate their effects on established seedling survival. To test this hypothesis, we selected established seedlings in the 20 ha forest dynamics plot in Tiantong as samples. Then, we used generalized linear mixed models to assess the effects of relative growth rate, biotic neighborhood factors (conspecific/heterospecific adult neighborhood indices, density of conspecific/heterospecific seedling neighbors, the amount of conspecific/heterospecific leaf litter from neighbors and abiotic micro-habitat factors (canopy openness, herbaceous coverage, elevation, slope, aspect, pH value, total nitrogen and total phosphorus in the soil on short-term established seedling survival rates. We used linear mixed models to assess the effects of biotic neighborhood factors and abiotic micro-habitat factors on relative growth rates of established seedlings. Results showed that relative growth rates have a significant, positive effect on established seedling survival, and this factor is the most important factor among potential influencing factors. In addition, canopy openness, as only one significant influencing factor, has a positive effect on relative growth rates of

  8. Why Seedlings Die: Linking Carbon and Water Limitations to Mechanisms of Mortality During Establishment in Conifer Seedlings

    Science.gov (United States)

    Reinhardt, K.; Germino, M. J.; Kueppers, L. M.; Mitton, J.; Castanha, C.

    2012-12-01

    BACKGROUND Recent ecophysiological studies aimed at explaining adult tree mortality during drought have examined the carbon (C)-exhaustion compared to the hydraulic-failure hypotheses for death. Prolonged drought leads to durations of stomatal closure (and thus limited C gain), which could result in long periods of negative C balance and fatal reductions in whole-plant C reserves (i.e., available non-structural carbohydrates ["NSC"]). Alternatively, C reserves may not decrease much but could become increasingly inaccessible to sink tissues in long dry-periods due to impediments to translocation of photosynthate (e.g., through disruption of hydrostatic pressure flow in phloem). As C reserves decline or become inaccessible, continued maintenance respiration has been hypothesized to lead to exhaustion of NSC after extended durations of drought, especially in isohydric plant species. On the other hand, hydraulic failure (e.g., catastrophic xylem embolisms) during drought may be the proximate cause of death, occurring before true C starvation occurs. Few studies have investigated specifically the mechanism(s) of tree death, and no published studies that we know of have quantified changes in NSC during mortality. EXPERIMENTAL DESIGN AND HYPOTHESES We conducted two studies that investigated whole-tree and tissue-specific C relations (photosynthetic C gain, respiration, dry-mass gain, and NSC pools) in Pinus flexilis seedlings during the initial establishment phase, which is characterized by progressive drought during summer. We measured survival, growth and biomass allocation, and C-balance physiology (photosynthetic C-gain and chlorophyll fluorescence, respiration C-use, and NSC concentrations) from germination to mortality. We hypothesized that 1) stomatal and biochemical limitations to C gain would constrain seedling survival (through inadequate seasonal C-balance), as has been shown for conifer seedlings near alpine treeline; 2) hydraulic constraints (embolisms and

  9. Effects of Cutting Density on Growth,Yield and Quality of Poplar Clone Seedlings

    Institute of Scientific and Technical Information of China (English)

    Fang Shengzuo; Tian Ye; Yuan Fayin

    2006-01-01

    In order to identify the optimum cutting density for producing the highest number of plantable seedlings of poplar clones,a split-plot randomized block design was used to establish four cutting densities in plots.Based on data on the survival,leaf area,seedling height,caliper,and biomass of 1-year-old seedlings of clones Nanlin-95,Nanlin-895,Nanlin-1388 and NL-80351,the growth characteristics and seedling quality under four cutting densities were analyzed.Results indicated that the leaf area,stern and leaf biomass,and caliper of seedlings of all four poplar clones increased with the decrease in cutting density.Leaf area index reached its highest level at the spacing of 40 cm×40 cm,while the aboveground biomass of the seedling on an area basis increased as the cutting density increased.Seedling quality at low cutting density was higher than that at closer cutting density.The quantity of first-grade seedlings (grade Ⅰ) for clones Nanlin-95 and Nanlin-895 was achieved at the spacing of 40 cm×50 cm;for NL-1388 and NL-80351,it was 50 cm×50 cm.According to the seedling quality and the number of plantable seedlings produced,the suggested cutting density for these four poplar clones was 50,000 stems/hm2.

  10. Higher Chilling-Tolerance of Grafted-Cucumber Seedling Leaves upon Exposure to Chilling Stress

    Institute of Scientific and Technical Information of China (English)

    LI Jian-yong; TIAN Hai-xia; LI Xin-guo; MENG Jing-jing; HE Qi-wei

    2008-01-01

    The roots of figleaf gourd (Cucurbita ficifolia, as rootstock) could improve the resistance of cucumber plants (Cucumis sativus L. cv. Jinyan 4, as scion) to low temperature. In this experiment, the root activity and photosynthetic activity of photosystems in the own-rooted and grafted-cucumber plants were studied at chilling temperature (4℃) under low irradiance (100 μmol m-2 s-1 PFD). Compared with dark adaptation seedlings, the chlorophyll a fluorescence transient curve and the oxidizable P700 (P700+) of both the own-rooted and grafted seedlings decreased, and PS2 and PSl of the own-rooted seedling leaves were more inhibited than that of grafted ones at the end of chilling stress. The reduced triphenyltetrazolium chloride (TTC), which was used to reflect the root activity, kept stable in grafted seedling roots at the end of chilling stress, while it decreased noticeably in the own-rooted seedling roots. These results implied that the root system activity of the grafted seedling roots was higher than that of the own-rooted ones. Superoxide dismutase (SOD) activity was higher in both the grafted seedling roots and leaves than that in own-rooted seedlings at both room temperature and chilling temperature. Upon exposure to chilling stress, the malondialdehyde (MDA) content, which reflects the degree of lipid peroxidation, increased markedly in the own-rooted seedling roots and leaves and kept stable in the grafted-cucumber seedlings.

  11. Implications of seed size for seedling survival in Carnegiea gigantea and Ferocactus wislizeni (Cactaceae)

    Science.gov (United States)

    Bowers, Janice E.; Pierson, E.A.

    2001-01-01

    Larger seeds have been shown to convey benefits for seedling survival but the mechanisms of this process are not well understood. In this study, seed size and seedling survival were compared for 2 sympatric cactus species, Carnegiea gigantea (Engelm.) Britt. & Rose and Ferocactus wislizeni (Engelm.) Britt. & Rose, in laboratory and field experiments in the northern Sonoran Desert. Both species have small seeds, but Ferocactus seeds are nearly twice as long and 3 times as heavy as those of Carnegiea. The difference in size is perpetuated after germination: new Ferocactus seedlings have 4 times the estimated volume of new Carnegiea seedlings. In an outdoor experiment, annual survivorship of both species was low but was 6 times higher for Ferocactus (6 seedlings, 8.1%) than Carnegiea (1 seedling, 1.4%). The pattern of seedling mortality in relation to temperature and rain suggests that, after the initial flush of seed and seedling predation, drought and heat took a greater toll on Carnegiea than Ferocactus seedlings, probably because the larger seedling volume of Ferocactus conferred greater drought tolerance. In addition, F. wislizeni could become established without benefit of nurse plants whereas C. gigantea could not; this might reflect differential tolerance to high soil temperatures.

  12. Effects of invasive rats and burrowing seabirds on seeds and seedlings on New Zealand islands.

    Science.gov (United States)

    Grant-Hoffman, Madeline N; Mulder, Christa P H; Bellingham, Peter J

    2010-04-01

    Rats (Rattus rattus, Rattus norvegicus, Rattus exulans) are important invaders on islands. They alter vegetation indirectly by preying on burrowing seabirds. These seabirds affect vegetation through nutrient inputs from sea to land and physical disturbance through trampling and burrowing. Rats also directly affect vegetation though consumption of seeds and seedlings. Seedling communities on northern New Zealand islands differ in composition and densities among islands which have never been invaded by rats, are currently invaded by rats, or from which rats have been eradicated. We conducted experimental investigations to determine the mechanisms driving these patterns. When the physical disturbance of seabirds was removed, in soils collected from islands and inside exclosures, seedling densities increased with seabird burrow density. For example, seedling densities inside exclosures were 10 times greater than those outside. Thus the negative effects of seabirds on seedlings, by trampling and uprooting, overwhelm the potentially beneficial effects of high levels of seed germination, seedling emergence, and possibly seed production, which result from seed burial and nutrient additions. Potential seedling density was reduced on an island where rats were present, germination of seeds from soils of this island was approximately half that found on other islands, but on this island seedling density inside exclosures was 7 times the density outside. Although the total negative effects of seabirds and rats on seedling densities are similar (reduced seedling density), the differences in mechanisms and life stages affected result in very different filters on the plant community.

  13. Effects of Seedbed Density on Seedling Morphological Characteristics of four Broadleaved Species

    Energy Technology Data Exchange (ETDEWEB)

    Yucedag, C.; Gailing, O.

    2012-11-01

    The aim of this study was to investigate the effects of seedling spacing on morphological characteristics of one year-old Amygdalus communis L., Prunus avium L., Pyrus elaeagnifolia Pall. and Eriolobus trilobatus (Poiret) Roemer seedlings under nursery conditions. Seedlings were grown in completely randomized blocks with four replications. Seedbeds were 1.2 m wide with 5 rows each 20 cm apart. Within-row spacings were chosen as 4, 8 and 12 cm to analyze the effect of seedlings density on growth performance. Seedling spacing significantly affected root collar diameter, shoot height, tap root length and number of fine roots in A. communis and P. avium, but not in P. elaeagnifolia and E. tribolatus. Additionally wider seedling spacings resulted in larger seedlings in A. communis and P. avium. In conclusion, it would be beneficial to use wider seedling spacing in order to obtain better seedling growth in A. communis and P. avium. Larger seedlings could also provide significant advantages because of reduced cultural activities and an expected higher growth and survival rate. (Author) 27 refs.

  14. Colonization with Arbuscular Mycorrhizal Fungi Promotes the Growth of Morus alba L. Seedlings under Greenhouse Conditions

    Directory of Open Access Journals (Sweden)

    Nan Lu

    2015-03-01

    Full Text Available Morus alba L. is an important tree species planted widely in China because of its economic value. In this report, we investigated the influence of two arbuscular mycorrhizal fungal (AMF species, Glomus mosseae and Glomus intraradices, alone and together, on the growth of M. alba L. seedlings under greenhouse conditions. The growth parameters and physiological performance of M. alba L. seedlings were evaluated 90 days after colonization with the fungi. The growth and physiological performance of M. alba L. seedlings were significantly affected by the AMF species. The mycorrhizal seedlings were taller, had longer roots, more leaves and a greater biomass than the non-mycorrhizae-treated seedlings. In addition, the AMF species-inoculated seedlings had increased root activity and a higher chlorophyll content compared to non-inoculated seedlings. Furthermore, AMF species colonization increased the phosphorus and nitrogen contents of the seedlings. In addition, simultaneous root colonization by the two AMF species did not improve the growth of M. alba L. seedlings compared with inoculation with either species alone. Based on these results, these AMF species may be applicable to mulberry seedling cultivation.

  15. Invasive rats alter woody seedling composition on seabird-dominated islands in New Zealand.

    Science.gov (United States)

    Grant-Hoffman, Madeline N; Mulder, Christa P; Bellingham, Peter J

    2010-06-01

    Invasive rats (Rattus rattus, R. norvegicus, R. exulans) have large impacts on island habitats through both direct and indirect effects on plants. Rats affect vegetation by extirpating burrowing seabirds through consumption of eggs, chicks, and adults. These seabirds serve as ecosystem engineers, affecting plant communities by burying and trampling seeds and seedlings, and by altering microclimate. Rats also directly affect plant communities by consuming seeds and seedlings. We studied the direct and indirect impacts of rats on the seedlings of woody plants on 21 islands in northern New Zealand. We compared seedling densities and richness on islands which differed in status with respect to rats: nine islands where rats never invaded, seven islands where rats were present at the time of our study, and five islands where rats were either eradicated or where populations were likely to be small as a result of repeated eradications and re-invasions. In addition, we compared plots from a subset of the 21 islands with different burrow densities to examine the effects of burrowing seabirds on plants while controlling for other factors that differ between islands. We categorized plant communities by species composition and seedling density in a cluster analysis. We found that burrow densities explained more variation in seedling communities than rat status. In areas with high seabird burrow density seedling densities were low, especially for the smallest seedlings. Species richness and diversity of seedlings, but not seedling density, were most influenced by changes in microclimate induced by seabirds. Islands where rats had been eradicated or that had low rat populations had the lowest diversity and richness of seedlings (and adults), but the highest seedling density. Seedling communities on these islands were dominated by Pseudopanax lessonii and Coprosma macrocarpa. This indicates lasting effects of rats that may prevent islands from returning to pre-invasion states.

  16. The role of genetic and chemical variation of Pinus sylvestris seedlings in influencing slug herbivory.

    Science.gov (United States)

    O'Reilly-Wapstra, Julianne M; Iason, Glenn R; Thoss, Vera

    2007-05-01

    This study investigated the genetic and chemical basis of resistance of Pinus sylvestris seedlings to herbivory by a generalist mollusc, Arion ater. Using feeding trials with captive animals, we examined selective herbivory by A. ater of young P. sylvestris seedlings of different genotypes and correlated preferences with seedling monoterpene levels. We also investigated the feeding responses of A. ater to artificial diets laced with two monoterpenes, Delta(3)-carene and alpha-pinene. Logistic regression indicated that two factors were the best predictors of whether seedlings in the trial would be consumed. Individual slug variation (replicates) was the most significant factor in the model; however, alpha-pinene concentration (also representing beta-pinene, Delta(3)-carene and total monoterpenes due to multicollinearity) of needles was also a significant factor. While A. ater did not select seedlings on the basis of family, seedlings not eaten were significantly higher in levels of alpha-pinene compared to seedlings that were consumed. We also demonstrated significant genetic variation in alpha-pinene concentration of seedlings between different families of P. sylvestris. Nitrogen and three morphological seedling characteristics (stem length, needle length and stem diameter) also showed significant genetic variation between P. sylvestris families. Artificial diets laced with high (5 mg g(-1) dry matter) quantities of either Delta(3)-carene or alpha-pinene, were eaten significantly less than control diets with no added monoterpenes, supporting the results of the seedling feeding trial. This study demonstrates that A. ater selectively feed on P. sylvestris seedlings and that this selection is based, in part, on the monoterpene concentration of seedlings. These results, coupled with significant genetic variation in alpha-pinene concentration of seedlings and evidence that slug herbivory is detrimental to P. sylvestris fitness, are discussed as possible evidence for A

  17. Clinorotation affects mesophyll photosynthetic cells in leaves of pea seedlings.

    Science.gov (United States)

    Adamchuk, N I

    1998-07-01

    Experiments with autotrophs in altered gravity condition have a grate significant for development of space biology. The main results of investigation in the photosynthetic apparatus state under microgravity condition have based on the experiments with maturity plants and their differentiated cells. The structural and functional organization of photosynthetic cells in seedlings is poor understandable still. Along with chloroplasts preserving a native membrane system in palisade parenchyma cells of the 29-day pea plant leaves in microgravity, chloroplasts with fribly packed or damaged granae, whose thylakoids appeared as vesicles with an electrontransparent content, were also observed. The investigation of preceding process induced these effects have a sense. That is why, the goal of our experiments was to perform the study of a structural organization of the photosynthetic cells of 3-d pair of pea seedlings leaves under the influence of clinorotation.

  18. Morpho-physiological changes in maize seedling sunder osmotic stress

    Directory of Open Access Journals (Sweden)

    Anđelković Violeta

    2012-01-01

    Full Text Available Drought is a major abiotic stress factor limiting crop growth, development and production worldwide. The objective of this study was to evaluate tolerance to osmotic stress of maize seedlings. More than 6,000 accessions from the Maize Research Institute gene bank were tested under controlled drought (at flowering in Egypt, and afterwards in temperate climate (Serbia and Macedonia. Out of 41 drought tolerant accessions in the field, five inbred lines were chosen for laboratory testing, as well as one drought sensitive line. These genotypes were exposed to 4% polyethylene glycol-PEG (Mr 10000 for 24 h and 48 h. Nine-day-old seedlings compared to control conditions were analyzed in root and shoot length, fresh and dry weight and proline content. Results showed reduction in all parameters under stress, while only proline content increased in all PEG treated genotypes compared to control.

  19. Starch bioengineering affects cereal grain germination and seedling establishment

    DEFF Research Database (Denmark)

    Shaik, Shahnoor Sultana; Carciofi, Massimiliano; Martens, Helle Juel;

    2014-01-01

    Cereal grain germination is central for plant early development, and efficient germination has a major role in crop propagation and malting. Endosperm starch is the prime energy reserve in germination and seedling establishment. In this study, it was hypothesized that optimized starch granule...... structure, and not only the endosperm starch content per se, is important for germination and seedling establishment. For that purpose, wild-type (WT), and specifically engineered degradable hyperphosphorylated (HP) starch and more resistant amylose-only (AO) starch barley lines were used. The transgenics...... showed no severe phenotypes and the WT and HP lines degraded the starch similarly, having 30% residual starch after 12 d of germination. However, the AO line showed significant resistance to degradation, having 57% residual starch. Interestingly, protein and β-glucan (BG) degradation was stimulated...

  20. Architectural ideotype of pear seedling in five hybrid combinations

    Directory of Open Access Journals (Sweden)

    Vasile GHIDRA

    1998-08-01

    Full Text Available The architectural ideotype - type of growing - was studied in a topcross experiment with five hybrid combinations in which Cluj 72-2-100 selection, typical spur, was used as a maternal tester. The analyzed seedlings were at the end of their sixth year of vegetation. There were no significant differences among the five hybrid combinations concerning the distributions of F1 seedling in the four accepted ideotypes (columnar, spur, standard, and weeping. A high variability was found for ideotype (between 18.8% in Cluj 72-2-100 x Napoca and 34.4% in Cluj 72-2-100 x Red Bartlett. The participation rate of genotype in the phenotypic manifestation of this character is relatively low. The coefficient of heritability in broad sense was 0.29 and the coefficient of heritability in narrow sense was very low, 0.001.

  1. QUALITY EVALUATION OF Cedrela fissilis SEEDS AND SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Edicléia Aparecida Iensen Cherobini

    2009-10-01

    Full Text Available Belonging to the Meliaceae family, cedro (Cedrela fissilis Vell. presents a great economical and ecological importance. The wood is light and easy to work, being suggested to the manufacturing of furniture in general, also it is used to reset degraded areas. The objective of this work was to evaluate the quality of Cedrela fissilis seedlings and seeds from Rio Grande do Sul, Santa Catarina and Paraná, through the accomplishment of varied tests of vigor, test of health and evaluation of the quality of seedlings produced from these seeds. The present study showed that the presence of fungi pathological potential – Aspergillus spp. and Penicillium spp. – can cause losses in the germination. Considering tests with seeds collected in the different states of the South Region, it was possible to verify that differences of the vigor levels exist. The fungi found in the seeds can cause damages in the production.

  2. Termite biocontrol on cacao seedling: Vetiver grass application

    OpenAIRE

    Du, Le; Truc, N.H.

    2008-01-01

    Just in the last decade, cacao (Theobroma cacao) has been introduced to the agroforestry systems in some upland provinces of southern Vietnam, especially in cashew plantation for improving the income of local farmers. However termite attack on cacao seedlings is the main constraint to the development of this crop in these systems. Chemical application is the only method available for farmers to protect their cacao crop. So far there is no study on non-chemical termite control method. An exper...

  3. Growth responses of Picea mongolica seedlings to defoliation rate

    Institute of Scientific and Technical Information of China (English)

    ZOU Chun-jing; HAN Shi-jie; QI Shu-yan; XU Wen-duo; LI Dao-tang

    2005-01-01

    Picea mongolica W. D. Xu. is an endemic species in China. The spruce forest is only found in semi-arid habitat in Inner Mongolia Autonomous Region of China. Based on the simulative defoliation experiment, it was proved that Picea mongolica seedlings had the compensatory and overcompensatory effects under the certain defoliation rate. The results of variance analysis on growth indexes showed that in PM Ⅰ (natural regeneration seedlings under Picea mongolica forest), the differences of H1 (height in June 23) and H2 (height in September 3) were extremely significant, and the difference of D(diameter at the breast height) were not significant. In PM Ⅱ (artificial regeneration seedlings under Betula platyphylla Suk. forest), the difference of H1 was significant, the difference of H2 was not significant, and the difference of D was extremely significant. The regression equations were established and the compensatory and overcompensatory points were obtained. In PM Ⅰ , the compensatory points of H1, H2, and D were 0.7628, 0.7436, 0.5725, and the overcompensatory points were 0.6056, 0.5802 and 0.2909 respectively. In PM Ⅱ, the compensatory points of H1, H2, and D are 0.5012, 0.3421, 0.2488, and the overcompensatory points are 0.4137, 0.2633 and 0.0747 respectively. These results suggested that the induction of compensatory growth mechanisms in spruce seedlings required a threshold level of defoliation, and the insects in Picea mongolica forest could be controlled in a certain degree.

  4. Evaluating first-year pine seedling survival plateau in Louisiana

    Science.gov (United States)

    Puskar N. Khana; Thomas J. Dean; Scott D. Roberts; Donald L. Grebner

    2016-01-01

    First-year seeding survival has been a continuing problem since the start of commercial pine plantation forestry in the 1950s. First-year survival of bare-root loblolly pine seedlings on intensively prepared sites in Louisiana has maintained a survival plateau between 79 to 89 percent with an average of about 82 percent. The specific objectives of this study were to...

  5. Cork oak (Quercus suber L.) seedlings acclimate to elevated

    OpenAIRE

    2012-01-01

    Leaf gas-exchange, leaf and shoot anatomy, wood density and hydraulic conductivity were investigated in seedlings of Quercus suber L. grown for 15 months either at elevated (700 lmol mol-1) or normal (350 lmol mol-1) ambient atmospheric CO2 concentrations. Plants were grown in greenhouses in a controlled environment: relative humidity 50% (±5), temperature similar to external temperature and natural light conditions. Plants were supplied with nutrients and two water re...

  6. Chloroplasts in seeds and dark-grown seedlings of lotus.

    Science.gov (United States)

    Ushimaru, Takashi; Hasegawa, Takahiro; Amano, Toyoki; Katayama, Masao; Tanaka, Shigeyasu; Tsuji, Hideo

    2003-03-01

    In most higher plants, mature dry seeds have no chloroplasts but etioplasts. Here we show that in a hydrophyte, lotus (Nelumbo nucifera), young chloroplasts already exist in shoots of mature dry seeds and that they give rise to mature chloroplasts during germination, even in darkness. These shoots contain chlorophyll and chlorophyll-binding proteins CP1 and LHCP. The unique features of chloroplast formation in N. nucifera suggest a unique adaptive strategy for seedling development correlated with the plant's habitat.

  7. Seedling Performance Associated with Live or Herbicide Treated Tall Fescue

    Directory of Open Access Journals (Sweden)

    Jonathan J. Halvorson

    2015-01-01

    Full Text Available Tall fescue is an important forage grass which can host systemic fungal endophytes. The association of host grass and endophyte is known to influence herbivore behavior and host plant competition for resources. Establishing legumes into existing tall fescue sods is a desirable means to acquire nitrogen and enhance the nutritive value of forage for livestock production. Competition from existing tall fescue typically must be controlled to ensure interseeding success. We used a soil-on-agar method to determine if soil from intact, living (L, or an herbicide killed (K tall fescue sward influenced germination and seedling growth of three cultivars of tall fescue (E+, MaxQ, and E− or legumes (alfalfa, red clover, and white clover. After 30 days, seedlings were larger and present in greater numbers when grown in L soil rather than K soil. Root growth of legumes (especially white clover and tall fescue (especially MaxQ were not as vigorous in K soil as L soil. While shoot biomass was similar for all cultivars of tall fescue in L soil, MaxQ produced less herbage when grown in K soil. Our data suggest establishing legumes or fescue cultivars may not be improved by first killing the existing fescue sod and seedling performance can exhibit significant interseasonal variation, related only to soil conditions.

  8. Endophytic fungi reduce leaf-cutting ant damage to seedlings.

    Science.gov (United States)

    Bittleston, L S; Brockmann, F; Wcislo, W; Van Bael, S A

    2011-02-23

    Our study examines how the mutualism between Atta colombica leaf-cutting ants and their cultivated fungus is influenced by the presence of diverse foliar endophytic fungi (endophytes) at high densities in tropical leaf tissues. We conducted laboratory choice trials in which ant colonies chose between Cordia alliodora seedlings with high (E(high)) or low (E(low)) densities of endophytes. The E(high) seedlings contained 5.5 times higher endophyte content and a greater diversity of fungal morphospecies than the E(low) treatment, and endophyte content was not correlated with leaf toughness or thickness. Leaf-cutting ants cut over 2.5 times the leaf area from E(low) relative to E(high) seedlings and had a tendency to recruit more ants to E(low) plants. Our findings suggest that leaf-cutting ants may incur costs from cutting and processing leaves with high endophyte loads, which could impact Neotropical forests by causing variable damage rates within plant communities.

  9. Gluconeogenesis from storage wax in the cotyledons of jojoba seedlings.

    Science.gov (United States)

    Moreau, R A; Huang, A H

    1977-08-01

    The cotyledons of jojoba (Simmondsia chinensis) seeds contained 50 to 60% of their weight as intracellular wax esters. During germination there was a gradual decrease in the wax content with a concomitant rise in soluble carbohydrates, suggesting that the wax played the role of a food reserve. Thin layer chromatography revealed that both the fatty alcohol and fatty acid were metabolized. The disappearance of wax was matched with an increase of catalase, a marker enzyme of the gluconeogenic process in other fatty seedlings. Subcellular organelles were isolated by sucrose gradient centrifugation from the cotyledons at the peak stage of germination. The enzymes of the beta oxidation of fatty acid and of the glyoxylate cycle were localized in the glyoxysomes but not in the mitochondria. The glyoxysomes had specific activities of individual enzymes similar to those of the castor bean glyoxysomes. An active alkaline lipase was detected in the wax bodies at the peak stage of germination but not in the ungerminated seeds. No lipase was detected in glyoxysomes or mitochondria. After the wax in the wax bodies had been extracted with diethyl ether, the organelle membrane was isolated and it still retained the alkaline lipase. The gluconeogenesis from wax in the jojoba seedling appears to be similar, but with modification, to that from triglyceride in other fatty seedlings.

  10. Fungi of the genus Fusarium as pathogens of soybean seedlings

    Directory of Open Access Journals (Sweden)

    Joanna Marcinkowska

    2013-12-01

    Full Text Available Twenty isolates of fungi of the genus Fusarium collected in the period 1980-1982 from various organs of diseased soybean plants were investigated. Eight of them proved pathogenic to soybean seedlings. The species F. culmorum was most numerously represented among the isolated (4 of 8 pathogens. Isolates of F. sambucinum were also pathogenic (2 of 4 and those of F. soloni (1 of 3, too. The only isolate of F. avenaceum also caused seedling blight. Two isolates of F. oxysporum and two of F. arthrosporioides were not pathogenic. Numerous isolates affected seed gernination and one greatly inhibited growth of the infected seedlings. Pathogenicity was tested in the laboratory in Petri plates on isolate cultures and on filter paper imbibed with fungal inoculum and, in the greenhouse on a peat and perlite substrate. The degree of infection and the character of the disease symptoms depended on the experimental conditions. The results of experiments in plates and in the greenhouse supplemented one another.

  11. [Thermal dissipation pathway in cucumber seedling leaves under hypoxia stress].

    Science.gov (United States)

    Jia, Yong-xi; Sun, Jin; Wang, Li-ping; Shu, Sheng; Guo, Shi-rong

    2011-03-01

    A water culture experiment was conducted to study the relationship between photosynthetic thermal dissipation and xanthophyll cycle in cucumber seedling leaves under hypoxia stress (the dissolved oxygen concentration in nutrient solution was 0.9-1.1 mg x L(-1)). Under the hypoxia stress, there was a significant decrease in the quantum yield of PS II photochemistry rate (phi(PS II)), net photosynthetic rate (Pn) under saturation light intensity, quanta yield (AQY), and maximal photochemical efficiency (Fv/Fm), suggesting that the photoinhibition of the seedling leaves was induced. Meanwhile, the thermal dissipation (NPQ) and the allocation of dissipation energy (D) by antenna increased, but the photochemical quenching apparent (q(p)) decreased, suggesting the enhancement of thermal dissipation in cucumber leaves under hypoxia stress. A positive correlation was observed between NPQ and xanthophyll de-epoxidation state (DEPS), and both of them were promoted by ascorbic acid (AsA) and inhibited by 1,4-dithiothreitol (DTT), suggesting that xanthophyll cycle was the major pathway of photosynthetic thermal dissipation in cucumber seedling leaves under hypoxia stress.

  12. Effects of gravel mulch on emergency of galleta grass seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, V.K.; Medrano, J.C.; Stanley, C.; Walo, M.D.

    1993-02-01

    Gravel mulches show promise as effective material on the US Dept. of Energy Nevada Test Site for stabilizing erosive soils and aiding plant establishment by conserving soil water. A greenhouse study was implemented to determine the effects of gravel mulch on seedling emergence and soil water, and optimal depths of gravel for various native plant species. Greenhouse flats were sown with seeds of nine species of native grasses, forbs, and shrubs. The flats were then treated with a variety of mulch treatments including, no mulch, a 1-cm layer of soil over seeds, and 2 to 3-cm and 4 to 5-cm layers of 3 to 25-mm mixed gravel. Superimposed over these treatments were 3 irrigation treatments. Seedling density data was collected daily, and soil water was monitored daily with the gravimetric method. This study showed that under a variety of soil water conditions, a 2--3 cm gravel layer may aid emergence of galleta grass. Results from this study also demonstrated that a deeper layer of gravel (4--5 cm) prohibits emergence, probably because it acts as a physical barrier to the seedlings. Galleta grass emergence can be used as a model for how other species might respond to these seedbed and irrigation treatments, provided they have adequate germination and are exposed to similar environmental conditions.

  13. Evaluation of Oxygen Deficit Stress on Germination Indicators and Seedling

    Directory of Open Access Journals (Sweden)

    F Hoseini

    2012-06-01

    Full Text Available To investigate the relationship oxygen deficit stress on germination indicators and seedling growth of five wheat cultivars in laboratory condition, an experiment with Randomized Complete Block design in factorial arrangement with three replications was conducted in 2008. The treatments consisted of five wheat cultivars (Chamran, Flat, Roshan, Stare and Shole as A factor, and two oxygen level (normal seed and seed under oxygen deficit stress conditions as B factor in each of these figures was done. Results showed that oxygen deficit stress caused to decrease for various cultivars germination percentage, germination rate, allometric coefficient, seed vigor index and other germination indicators. Therefore, this test as a suitable method for determining the quality of various seed lot can be used in the water logging condition. In addition, among different cultivars characterized that Roshan cultivar was more resistant to oxygen deficit stress than Chamran, Flat and Star cultivars. Although Chamran cultivar is common cultivar in Khouzestan, but of look most germination indicators arranged as weak seed class. The highest correlation coefficients among the tested cultivars have been related to seed vigor with seedling length and dry weight of radicle with seedling with 0.92 and 0.90, respectively.

  14. Morphogenesis of rice and Arabidopsis seedlings in space.

    Science.gov (United States)

    Hoson, T; Soga, K; Mori, R; Saiki, M; Wakabayashi, K; Kamisaka, S; Kamigaichi, S; Aizawa, S; Yoshizaki, I; Mukai, C; Shimazu, T; Fukui, K; Yamashita, M

    1999-12-01

    Seedlings of rice (Oryza saliva L.) and Arabidopsis (A. thaliana L.) were cultivated for 68.5 hr in the RICE experiment on board during Space Shuttle STS 95 mission, and changes in their growth and morphology were analyzed. Microgravity in space stimulated elongation growth of both rice coleoptiles and Arabidopsis hypocotyls by making their cell walls extensible. In space, rice coleoptiles showed an inclination toward the caryopsis in the basal region and also a spontaneous curvature in the same direction in the elongating region. These inclinations and curvatures were more prominent in the Koshihikari cultivar compared to a dwarf cultivar, Tan-ginbozu. Rice roots elongated in various directions including into the air on orbit, but two thirds of the roots formed a constant angle with the axis of the caryopsis. In space, Arabidopsis hypocotyls also elongated in a variety of directions and about 10% of the hypocotyls grew into the agar medium. No clear curvatures were observed in the elongating region of Arabidopsis hypocotyls. Such a morphology of both types of seedlings was fundamentally similar to that observed on a 3 D clinostat. Thus, it was confirmed by the RICE experiment that rice and Arabidopsis seedlings perform an automorphogenesis under not only simulated but also true microgravity conditions.

  15. GAS EXCHANGE AND CARBOHYDRATE PARTITIONING IN COFFEE SEEDLINGS UNDER WATERLOGGING

    Directory of Open Access Journals (Sweden)

    Helbert Rezende de Oliveira Silveira

    2015-04-01

    Full Text Available Irrigation has enhanced coffee production in several regions of Brazil. However, with the increase in irrigated crop areas, problems related to the frequent and poorly planned usage of irrigation may arise. Since there are few studies related to the physiological alterations in coffee plants exposed to water excess, we evaluated the effects of waterlogging on metabolism and partitioning of carbohydrates, levels of photosynthetic pigments and gas exchange in seedlings of two commercial coffee cultivars (Mundo Novo and Catuaí. After acclimation, seedlings with eight pairs of fully expanded leaves were cultivated under three water availability conditions: field capacity, intermittent waterlogging and continuous waterlogging. Gas exchange and the levels of chlorophyll, carotenoids and carbohydrates were evaluated during the five months after the beginning of the treatments. Waterlogging reduced the rates of photosynthesis and transpiration, leading to lower activity of the carboxylative step of photosynthesis and culminating in the reduction of carbohydrate partitioning in coffee seedlings. Although many physiological parameters were affected by waterlogging, the cultivars in our study survived for five months under stressful conditions.

  16. Effects of tip-pruning treatment on source-sink regulation of Catharanthus roseus seedlings

    Institute of Scientific and Technical Information of China (English)

    GAO Yang; ZHANG Xue-ke; GUO Xiao-rui; SUN Yan-fei; ZU Yuang-gang

    2006-01-01

    Fifty cultivated Catharanthus roseus seedlings were selected for tip-pruning treatment and the effects of tip-pruning on seedling growth and source-sink regulation were investigated for revealing physiological mechanisms of plants. The results showed that tip-pruning treatment resulted in obvious inhibition of apical dominance and enhancement of branching numbers. The contents of soluble sugars, acid sucrose invertase activity (AI) had a great change in differently positional leaves of the seedling. The sink strength in tip leaves of seedlings dramatically declined after tip-pruning treatment, while that in the leaves at the middle and bottom of seedlings had no obvious changes. The inhibition of apical dominance of tip leaves of seedlings was caused by the diminished sink strength due to tip-pruning treatment,

  17. Effects of Ectomycorrhizal Fungi on Growth of Seedlings of Pinus densiflora.

    Science.gov (United States)

    Sim, Mi-Yeong; Eom, Ahn-Heum

    2006-12-01

    This study was conducted to investigate the different effects of ectomycorrhizal fungal (ECMF) species on the growth of seedlings of Pinus densiflora, and the effects of ECMF diversity on plant productivity. A total of five species of ECMF were isolated from root tips of pine seedlings collected from Mt. Songni and used as inocula. Pots containing pine seedlings were inoculated with either a single ECMF species or a mixture of five ECMF species. All of the seedlings formed ECM on their roots except for the control plants. The pine seedlings' growth responses varied by the different ECMF species. Also, pine seedlings inoculated with a mixture of five ECMF species showed the highest growth response. The results of the study suggest that the colonization of diverse species of ECMF will increase plant productivity, and the selection of suitable ECMF species could be an important factor for plant growth.

  18. Growth response of Pinus densiflora seedlings inoculated with three indigenous ectomycorrhizal fungi in combination

    Directory of Open Access Journals (Sweden)

    M Dalong

    2011-09-01

    Full Text Available Pinus densiflora seedlings were inoculated with three indigenous ectomycorrhizal fungi (Cenococcum geophilum, Rhizopogon roseolus and Russula densifolia in single-, two-, and three-species treatments. After 8 months, the colonization rates of each ectomycorrhizal species, seedling growth and the nutrition were assessed in each treatment. P. densiflora seedlings inoculated with different ECM species composition showed an increase in height and basal diameter and improved seedling root and shoot nutrition concentrations compared to control treatment. Generally, combined inoculation had a more positive influence on the seedlings than the single inoculation. The three-species inoculation presented the highest growth and basal diameter and concentration of most nutrients except potassium. In conclusion, the results provided strong evidence for benefits of combined inoculation with the indigenous ectomycorrhizal fungi on P. densiflora seedlings under controlled conditions.

  19. Growth response of Pinus densiflora seedlings inoculated with three indigenous ectomycorrhizal fungi in combination.

    Science.gov (United States)

    Dalong, M; Luhe, W; Guoting, Y; Liqiang, M; Chun, L

    2011-07-01

    Pinus densiflora seedlings were inoculated with three indigenous ectomycorrhizal fungi (Cenococcum geophilum, Rhizopogon roseolus and Russula densifolia) in single-, two-, and three-species treatments. After 8 months, the colonization rates of each ectomycorrhizal species, seedling growth and the nutrition were assessed in each treatment. P. densiflora seedlings inoculated with different ECM species composition showed an increase in height and basal diameter and improved seedling root and shoot nutrition concentrations compared to control treatment. Generally, combined inoculation had a more positive influence on the seedlings than the single inoculation. The three-species inoculation presented the highest growth and basal diameter and concentration of most nutrients except potassium. In conclusion, the results provided strong evidence for benefits of combined inoculation with the indigenous ectomycorrhizal fungi on P. densiflora seedlings under controlled conditions.

  20. Biochemical contents of pepper seedlings inoculated with phytophthora infestans and arbuscular mycorrhiza

    Directory of Open Access Journals (Sweden)

    Odebode A.C.

    2004-01-01

    Full Text Available The effect of interactions between Arbuscular Glomus etunicatum and fungus Phytophthora infestans on biochemical contents of pepper plants was investigated in a greenhouse experiment. The sugar contents (i.e. Glucose fructose and sucrose were higher in the control and mycorrhizal inoculated pepper seedlings and the lowest in pathogen inoculated seedlings. Free amino acids were the highest in the simultaneously inoculated pepper seedlings while total phenol was found to be the highest in pepper seedlings inoculated with P. infestans. The levels of nitrogen, phosphorus and potassium varied in the inoculated pepper seedlings without any significant difference in the treatment. The results obtained suggest protective influence of mycorrhiza by enhancing the nutritional status of the inoculated pepper seedlings.

  1. Root graviresponsiveness and columella cell structure in carotenoid-deficient seedlings of Zea mays

    Science.gov (United States)

    Moore, R.; McClelen, C. E.

    1985-01-01

    Root graviresponsiveness in normal and carotenoid-deficient mutant seedlings of Zea mays was not significantly different. Columella cells in roots of mutant seedlings were characterized by fewer, smaller, and a reduced relative volume of plastids as compared to columella cells of normal seedlings. Plastids in columella cells of mutant seedlings possessed reduced amounts of starch. Although approximately 10 per cent of the columella cells in mutant seedlings lacked starch, their plastids were located at the bottom of the cell. These results suggest that (i) carotenoids are not necessary for root gravitropism, (ii) graviresponsiveness is not necessarily proportional to the size, number, or relative volume of plastids in columella cells, and (iii) sedimentation of plastids in columella cells may not result directly from their increased density due to starch content. Plastids in columella cells of normal and mutant seedlings were associated with bands of microtubule-like structures, suggesting that these structures may be involved in 'positioning' plastids in the cell.

  2. Quality assessment of truffle-inoculated seedlings in Italy: proposing revised parameters for certification

    Directory of Open Access Journals (Sweden)

    Domizia Donnini

    2014-08-01

    Full Text Available Aim of study: the main aims of this study were to evaluate the quality of truffle-inoculated seedlings produced by commercial nurseries in Italy and to identify their minimum requisites in terms of plant age, health, homogeneity, and cut-off percentage of inoculated Tuber and non-Tuber ectomycorrhizae, based on the analysis of an extensive sample of seedlings subjected to quality control and certification.Area of study: truffle-inoculated seedlings produced by Italian commercial nurseries.Material and Methods: analysis of truffle-inoculated seedlings for health and quality standards; recording of presence of inoculated Tuber spp. and other concurrent fungi according to the official Italian method for certification; selective amplification of ectomycorrhizal DNA by PCR species-specific primers.Main results: We showed that mycorrhization levels in truffle-inoculated seedlings increased with time after truffle-spore inoculation. The highest mean percentage of the inoculated Tuber spp., but also the highest presence of contaminants, were recorded after three years. The mycorrhization level of Tuber melanosporum and T. aestivum was higher in Corylus and Ostrya seedlings than in Q. ilex and Q. pubescens, but the latter two host species showed the lowest presence of other ectomycorrhizal fungi. Mycorrhization level distribution in truffle-inoculated seedlings of suitable batches differed very little from the distribution in only all suitable seedlings. Truffle seedlings with other Tuber spp. were very few and even absent after three years. The general quality of Italian truffle-inoculated seedlings is high but can be improved even further by revising the parameters used for their certification.Research highlights: Mycorrhization assessment in truffle-inoculated seedlings produced by commercial nurseries and a revision of the parameters of quality standards following several years of certification in Italy.Keywords: Truffle cultivation; truffle

  3. Characteristics of water relations in seedling of Machilus yunnanensis and Cinnamomum camphora under soil drought condition

    Institute of Scientific and Technical Information of China (English)

    TANG Tian-tian; ZHAO Lin-sen

    2006-01-01

    The soil drought stress experiment in different durations (no watering within 3d, 6d, 9d, 11d individually) was conducted to study the drought-resistant capacity of one-year-old seedlings for the native tree species (Machilus yunnanensis) in Yunnan Province and the introduced tree species (Cinnamomum camphora). The leaf water potential, chlorophyll content, proline content and plasma membrane permeability for two species seedlings were measured in different soil drought conditions. The results showed that, on the 9th day of drought stress, the leaf water potential of two species decreased obviously, whereas the free proline content and plasma membrane permeability increased sharply. On the 11th day, the leaf water potential of C. camphora seedlings was lower than that of M. yunnanensis seedlings; the plasma membrane permeability in C. camphora seedling leaves increased much more than that in M. yunnanensis seedling leaves, which showed that the injury to the former by soil drought stress was more severe than that to the latter. The free proline content in M. yunnanensis seedling leaves continued to increase on the 11th day, but that in the C. camphora seedling leaves started to drop obviously, indicating that the reduction of osmotic regulation substance in C. camphora seedling leaves after the 11th day was unable to maintain the osmotic balance between the plasma system and its surroundings and the water loss occurred inevitably. Comprehensively, M. yunnanensis seedlings enhanced the drought-resistance in the course of soil drought stress by maintaining higher leaf water potential and by increasing osmotic regulation substance to promote cell plasma concentration and maintain membrane structure integrity so as to reduce water loss. The subordination function index evaluated with fuzzy mathematic theory also showed that the drought-resistant capacity ofM. yunnanensis seedlings was stronger than that of C. camphora seedlings.

  4. Tree fern trunks facilitate seedling regeneration in a productive lowland temperate rain forest.

    Science.gov (United States)

    Gaxiola, Aurora; Burrows, Larry E; Coomes, David A

    2008-03-01

    Seedling regeneration on forest floors is often impaired by competition with established plants. In some lowland temperate rain forests, tree fern trunks provide safe sites on which tree species establish, and grow large enough to take root in the ground and persist. Here we explore the competitive and facilitative effects of two tree fern species, Cyathea smithii and Dicksonia squarrosa, on the epiphytic regeneration of tree species in nutrient-rich alluvial forests in New Zealand. The difficulties that seedlings have in establishing on vertical tree fern trunks were indicated by the following observations. First, seedling abundance was greatest on the oldest sections of tree fern trunks, near the base, suggesting that trunks gradually recruited more and more seedlings over time, but many sections of trunk were devoid of seedlings, indicating the difficulty of establishment on a vertical surface. Second, most seedlings were from small-seeded species, presumably because smaller seeds can easily lodge on tree fern trunks. Deer browsing damage was observed on 73% of epiphytic seedlings growing within 2 m of the ground, whereas few seedlings above that height were browsed. This suggests that tree ferns provide refugia from introduced deer, and may slow the decline in population size of deer-preferred species. We reasoned that tree ferns would compete with epiphytic seedlings for light, because below the tree fern canopy photosynthetically active radiation (PAR) was about 1% of above-canopy PAR. Frond removal almost tripled %PAR on the forest floor, leading to a significant increase in the height growth rate (HGR) of seedlings planted on the forest floor, but having no effects on the HGRs of epiphytic seedlings. Our study shows evidence of direct facilitative interactions by tree ferns during seedling establishment in plant communities associated with nutrient-rich soils.

  5. Growth Responses of Acacia mangium and Paraserianthes falcataria Seedlings on Different Soil Origin under Nursery Condition

    Directory of Open Access Journals (Sweden)

    Tirtha Ayu Paramitha

    2015-12-01

    Full Text Available The objective of the present study was to examine the growth responses of Acacia mangium (mangium and Paraserianthes falcataria (sengon seedlings growing on different soil origin under nursery condition. This study was started in September 2012 and terminated in March 2013.  The seedlings were grown from seeds sown in a plastic box filled with sterilized sands. One week after sowing, the seedlings were transplanted into polybags contained sterilized soils originated from secondary forest, Imperata cylindrica grassland and ex-coal mining. The number of all seedlings were 180 seedlings consisted of 3 different soils, 2 species of seedlings with 10 seedlings replicated 3 times. Assessment was conducted one week after transplanting, then subsequently monitored every 2 weeks, except dry weighing and counting nodules were performed at the end of the study. A completely randomized design was used in this study. The data was analyzed using Costat software. The study resulted that the different of soil origin influenced on all growth variables of mangium and sengon of 4.5 months old. The survival rate of seedlings, height and diameter increments, dry weight and root nodules were better in both species of seedlings growing on soil originated from secondary forest and Imperata grassland compared with the soil from ex-coal mining. But the survival rates of sengon seedlings were higher than that of mangium on these three soils. The highest dry weight of sengon seedlings was achieved on soil originated from secondary forest. In the present study, soil originated from secondary forest increased more in weight of shoot than root, so that the shoot-root ratio was unbalanced more than one. Based on the results of this study, it is recommended that soil from secondary forest and Imperata grassland can be used as growing media for mangium and sengon seedlings in the nursery.

  6. Book review: The Tallgrass Prairie Center guide to seed and seedling identification in the Upper Midwest

    Science.gov (United States)

    Larson, Diane L.; Galatowitsch, Susan M.

    2011-01-01

    This attractive, slim volume provides a wonderful introduction to a neglected aspect of prairie plant identification: seeds and seedlings. Williams, and the illustrator Brent Butler, take the mystery out of dichotomous keys with clear descriptions, vivid illustrations, and abundant photographs of characteristics that distinguish common, tallgrass prairie, seedlings. A botanical novice should have no problem using this book to identify seedlings in their prairie garden – presuming that they planted only those species included in the book (more on that later).

  7. Wood Anatomy of the Neotropical Sapotaceae. XX. Manilkara

    Science.gov (United States)

    1981-06-01

    aver. of 760 pm). Tyloses commonly thin-walled but frequently thick-walled or sclerotic in the denser specimens. Very large crystals were observed...frequently in the tyloses of albescens and jaimiqui, in most instances would be classified as two-sized; lacking or very sporadic occurrence in the other

  8. Identification and Seedlings Growth Evaluation of Shorea Species-Producing Tengkawang

    Directory of Open Access Journals (Sweden)

    Eritrina Windyarini

    2015-06-01

    Full Text Available Most of  non timber forest product (NTFP utilization taken from natural forests which decrease on productivity annually, including tengkawang producer species which taken from West Kalimantan natural forests. This condition needs an effort to preserve those species from natural population utilization through plantation forest development that require spesific strategy. This study was part of breeding strategy of shorea species producing tengkawang which aimed to species identify and seedling growth evaluation used genetic material from 2 (two population from West Kalimantan. The research was arranged in 2 (two steps, i.e.1 species identification used morphology characteristic difference, and 2 seedling growth evaluation (height,diameter,sturdiness. Seedling growth evaluation was arranged in RCBD, with 5 plot (combination of species and source population, contained 25 seedlings and 4 replications (blocks. The result showed that seedlings of shorea species producing tengkawang, i.e. S.stenoptera,  S.macrophylla, and S.gysbertsiana can be different from its stipulae morphology characteristic. Growth of 10 months shorea species producing tengkawang seedlings were significantly different on height and sturdiness. Seedlings height were 67,19 – 88,79 cm, seedlings diameter 9,65 – 10,33 mm and sturdiness 7 – 9,21 in range. The best seedling growth was S.stenoptera and S.macrophylla from Gunung Bunga, West Kalimantan.

  9. Identification and Seedlings Growth Evaluation of Shorea Species-Producing Tengkawang

    Directory of Open Access Journals (Sweden)

    Eritrina Windyarini

    2015-06-01

    Full Text Available Most of non timber forest product (NTFP utilization taken from natural forests which decrease on productivity annually, including tengkawang producer species which taken from West Kalimantan natural forests. This condition needs an effort to preserve those species from natural population utilization through plantation forest development that require spesific strategy. This study was part of breeding strategy of shorea species producing tengkawang which aimed to species identify and seedling growth evaluation used genetic material from 2 (two population from West Kalimantan. The research was arranged in 2 (two steps, i.e.1 species identification used morphology characteristic difference, and 2 seedling growth evaluation (height,diameter,sturdiness. Seedling growth evaluation was arranged in RCBD, with 5 plot (combination of species and source population, contained 25 seedlings and 4 replications (blocks. The result showed that seedlings of shorea species producing tengkawang, i.e. S.stenoptera, S.macrophylla, and S.gysbertsiana can be different from its stipulae morphology characteristic. Growth of 10 months shorea species producing tengkawang seedlings were significantly different on height and sturdiness. Seedlings height were 67,19 – 88,79 cm, seedlings diameter 9,65 – 10,33 mm and sturdiness 7 – 9,21 in range. The best seedling growth was S.stenoptera and S.macrophylla from Gunung Bunga, West Kalimantan.

  10. Effects of filamentous macroalgae mats on growth and survival of eelgrass, Zostera marina, seedlings

    DEFF Research Database (Denmark)

    Rasmussen, Jonas; Olesen, Birgit; Krause-Jensen, Dorte

    2012-01-01

    A laboratory experiment was conducted to assess the effect of filamentous algae mats on the performance of seedlings of the eelgrass, Zostera marina. The seedlings were covered by three levels (3, 6 and 9 cm) of natural (Chaetomorpha linum) and imitation algae mats and it was hypothesized...... that the effects of the natural algae on seedling growth may be more severe because of the metabolic demands of the algae. Results show that coverage by both C. linum and imitation algae significantly reduced seedling growth and increased allocation of resources to above ground tissues. No clear effects of algae...

  11. [Effects of grafting on physiological characteristics of melon (Cucumis melo) seedlings under copper stress].

    Science.gov (United States)

    Tan, Ming-min; Zhang, Xin-ying; Fu, Qiu-shi; He, Zhong-qun; Wang, Huai-song

    2014-12-01

    The effects of grafting on physiological characters of melon (Cucumis melo) seedlings under copper stress were investigated with Pumpkin Jingxinzhen No. 3 as stock and oriental melon IVF09 as scion. The results showed that the physiological characters of melon seedlings were inhibited significantly under copper stress. Compared with self-rooted seedlings, the biomass, the contents of photosynthetic pigment, glucose and fructose, the photosynthetic parameters, the activities of sucrose phosphate synthase, neutral invertase and acid invertase in the leaves of the grafted seedlings were increased significantly. The uptake of nutrients was improved with the contents of K, P, Na increased and the content of Cu decreased. When the concentration of Cu2+ stress was 800 micromol L(-1), the contents of Cu in the leaves and roots of the grafted seedlings were decreased by 31.3% and 15.2%, respectively. Endogenous hormone balance of seedlings was improved by grafting. In the grafted seedlings, the content of IAA and peroxidase activity were higher, whereas the contents of ABA, maleicdialdehyde, the activities of superoxide dismutase and catalase were lower than that in the control. It was concluded that the copper stress on the physiological characters of melon seedlings was relieved by grafting which improved the resistance of the grafted seedlings.

  12. Effects of Exogenous Cinnamic Acids on the Growth and Physiological Characteristics of Cucumber Seedlings

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In order to study the effects of exogenous cinnamic acids on plant growth, contents of photosynthetic pigment, root activities and ATPase activities of root membrane at cucumber seedling stage, the seedlings of Shandong Mici cucumber were tested. The results showed that seedlings growth, contents of photosynthetic pigment, root activities and ATPase activities of root membrane were inhibited by cinnamic acids. The growth and root activities of seedlings were significantly cinnamic acids, whereas ATPase activities exhibited a higher sensitivity and greatly decreased in the soil amended with 50 mg kg-1 cinnamic acids. These results suggested that cinnamic acids could induce a stress condition, and the stress intensities increased with enhanced cinnamic acid concentration.

  13. Research and Development of Statistical Analysis Software System of Maize Seedling Experiment

    Directory of Open Access Journals (Sweden)

    Hui Cao

    2014-03-01

    Full Text Available In this study, software engineer measures were used to develop a set of software system for maize seedling experiments statistics and analysis works. During development works, B/S structure software design method was used and a set of statistics indicators for maize seedling evaluation were established. The experiments results indicated that this set of software system could finish quality statistics and analysis for maize seedling very well. The development of this software system explored a new method for screening of maize seedlings.

  14. Variation in chromosome number in the seedling progeny of a somaclone of Paspalum dilatatum

    Institute of Scientific and Technical Information of China (English)

    ZHUJM; LJDAVIES; 等

    1994-01-01

    The somaclone,C39,derived by tissue culture from the obligate apomict Paspalum dilatatum cv Raki(2n=50),had 50 chromosomes and a karyotype apparently identical to Raki.SC2 seedlings of C39 showed a high degree of phenotypic variation which was often associated with increased chromosome numbers,but some of the variant seedlings were karyotypically indistinguishable from Raki or C39.Plants with increased chromosome numbers exhibited a high degree of intraplant chromosome variation(aneusomaty).In one of the SC2 seedlings,the chromosome number of root tip cells varied from 58 to 82 and in several other seedlings the range was more than 10.The results suggested that the ability to form seed apomictically was much reduced in C39 and that this plant showed some capacity for sexual reproduction and the resulting seedlings,with a chromosome number of about 70,were genetically unstable.Of 11 SC2 seedlings examined cytologically,6 did not produce any viable seed.Seedlings grown from seed of the remaining 5 plants showed that aneusomaty persisted in the SC3 generation.SC3 seedlings which were phenotypically similar to their maternal parent showed a similar range of chromosome numbers to that parent.Some of the SC3 seedlings exhibited an even wider range of chromosome numbers(e.g.56-136),and these plants were all dwarfs.

  15. Improving seedling growth in longleaf pine plantations with nematicidal soil fumigants.

    Science.gov (United States)

    Ruehle, J L

    1969-07-01

    In-row, preplanting fumigation with DD and DBCP in a longleaf pine plantation was evaluated for nematode control, improved seedling survival, and early and uniform release of seedlings from the grass stage. Only DD significantly lowered the nematode population during the first growing season. DBCP not only failed to control nematodes, but was phytotoxic. Fumigation had little effect on seedling survival. Seedlings in rows fumigated with DD started height growth earlier and produced taller trees after 5 years than those in nonfumigated rows.

  16. Community-Wide Spatial and Temporal Discordances of Seed-Seedling Shadows in a Tropical Rainforest

    Science.gov (United States)

    Rother, Débora Cristina; Pizo, Marco Aurélio; Siqueira, Tadeu; Rodrigues, Ricardo Ribeiro; Jordano, Pedro

    2015-01-01

    Several factors decrease plant survival throughout their lifecycles. Among them, seed dispersal limitation may play a major role by resulting in highly aggregated (contagious) seed and seedling distributions entailing increased mortality. The arrival of seeds, furthermore, may not match suitable environments for seed survival and, consequently, for seedling establishment. In this study, we investigated spatio-temporal patterns of seed and seedling distribution in contrasting microhabitats (bamboo and non-bamboo stands) from the Brazilian Atlantic Forest. Spatial distribution patterns, spatial concordance between seed rain and seedling recruitment between subsequent years in two fruiting seasons (2004–2005 and 2007–2009), and the relation between seeds and seedlings with environmental factors were examined within a spatially-explicit framework. Density and species richness of both seeds and seedlings were randomly distributed in non-bamboo stands, but showed significant clustering in bamboo stands. Seed and seedling distributions showed across-year inconsistency, suggesting a marked spatial decoupling of the seed and seedling stages. Generalized linear mixed effects models indicated that only seed density and seed species richness differed between stand types while accounting for variation in soil characteristics. Our analyses provide evidence of marked recruitment limitation as a result of the interplay between biotic and abiotic factors. Because bamboo stands promote heterogeneity in the forest, they are important components of the landscape. However, at high densities, bamboos may limit recruitment for the plant community by imposing marked discordances of seed arrival and early seedling recruitment. PMID:25856393

  17. Influence of slow disintegrating fertilizer rates on quality of gazania (Gazania rigens L. seedlings

    Directory of Open Access Journals (Sweden)

    Vujošević Ana

    2007-01-01

    Full Text Available The work has examined the influence of slow disintegrating fertilizer rates of Scotts (Osmocote Exact formulation 15:9:9:MgO + Me on quality of Gazania rigens L. seedlings. The seedlings of Gazania rigens L. was produced in polystyrene containers (speedling system and polypropylene pots (pot system. During the production of seedlings the fertilizer has been applied in rates (0, 1, 2, 3, and 4g/l. The results show that the fertilizer rate of substrata 4g/l influences the qualitative properties of Gazania rigens L. seedlings.

  18. SOURCES OF MYCORRHIZAL INFECTION OF SHOREA ACUMINATA SEEDLINGS UNDER LABORATORY CONDITIONS

    Directory of Open Access Journals (Sweden)

    LEE Su SEE

    1995-01-01

    Full Text Available Uninoculated dipterocarp seedlings raised in normal field soil in nurseries were always found to have mycorrhizas after a few months. This study set out to determine whether dipterocarp seedlings could continue to grow and develop in the absence of mycorrhizas and also to determine possible sources of mycorrhizal infection of dipterocarp seedlings raised under laboratory conditions using Shorea acuminata as a typical example. Seedlings were planted in capped or uncapped perspex boxes containing sterile or non-sterile field soil and watered daily with sterile water or tap water. Seedling growth and development of mycorrhizas were monitored at monthly intervals for up to seven months. Seedlings grown in sterile soil remained uninfected after seven months while infection was found in some of the seedlings grown in normal soil regardless of whether they had been watered with tap water or sterile water. This showed that field soil (i.e. under grass far from the forest contained suitable inoculum for forest tree seedlings. Tap water and the air were not important sources of infection. However, mycorrhizal infection was very uneven indicating that the inoculum was probably very unevenly distributed in the soil or that the inoculum density was rather low. Seedlings grown in sterile soil showed better growth than those grown in normal soil and infection of roots by parasitic fungi in the latter was also observed.

  19. Analysis of peg formation in cucumber seedlings grown on clinostats and in a microgravity (space) environment

    Science.gov (United States)

    Link, B. M.; Cosgrove, D. J.

    1999-01-01

    In young cucumber seedlings, the peg is a polar out-growth of tissue that functions by snagging the seed coat, thereby freeing the cotyledons. Previous studies have indicated that peg formation is gravity dependent. In this study we analyzed peg formation in cucumber seedlings (Cucumis sativus L. cv Burpee Hybrid II) grown under conditions of normal gravity, microgravity, and simulated microgravity (clinostat rotation). Seeds were germinated on the ground, in clinostats and on board the space shuttle (STS 95) for 1-2 days, frozen and subsequently examined for their stage of development, degree of hook formation, number of pegs formed, and peg morphology. The frequency of peg formation in space grown seedlings was found to be nearly identical to that of clinostat grown seedlings and to differ from that of seedlings germinated under normal gravity only in a minority of cases; approximately 6% of the seedlings formed two pegs and nearly 2% of the seedlings lacked pegs, whereas such abnormalities did not occur in ground controls. The degree of hook formation was found to be less pronounced for space grown seedlings, compared to clinostat grown seedlings, indicating a greater degree of decoupling between peg formation and hook formation in space. Nonetheless, in all seedlings having single pegs and a hook, the peg was found to be positioned correctly on the inside of the hook, showing that there is coordinate development even in microgravity environments. Peg morphologies were altered in space grown samples, with the pegs having a blunt appearance and many pegs showing alterations in expansion, with the peg extending out over the edges of the seed coat and downwards. These phenotypes were not observed in clinostat or ground grown seedlings.

  20. Fuel reduction at a Spanish heathland by prescribed fire and mechanical shredding: effects on seedling emergence.

    Science.gov (United States)

    Fernández, Cristina; Vega, José A; Fonturbel, Teresa

    2013-11-15

    Traditional heathland burning has declined in Spain, leading to fuel accumulation and fuel reduction treatments have become common for severe wildfire hazard reduction. These methods need to maintain the botanical composition of those shrub communities. Prescribed fire has been widely used in the past, but we need to compare mechanical fuel reduction with prescribed fire because it is easier and safer to carry out in a wide range of weather conditions. This information could be particularly useful in flammable ecosystems all over the world where traditional anthropogenic burning has declined. In this study, we compared the effects of prescribed burning and mechanical shredding on the seedling emergence and its relation to the mature vegetation in a fire-prone heathland dominated by Erica australis L. and Pterospartum tridentatum (L.) Willk., in Galicia (NW Spain). We combined a greenhouse experiment with periodic field inventories of seedling emergence. In the greenhouse study, the seedling emergence was significantly higher in the soil samples after burning (383 seedlings m(-2)) than in samples before burning (242 seedlings m(-2)). In contrast, there was no significant difference in seedling density before and after mechanical shredding (243 compared with 261 seedlings m(-2)). Also, the number of seedlings that emerged after burning was significantly higher than that emerged after mechanical shredding. The maximum temperatures at the soil organic layer surface during burning were significantly and positively related to the density of Halimium lasianthum ssp. alyssoides and P. tridentatum seedlings. In the field study, the observed seedling density was very low both after prescribed burning and mechanical shredding. There was a high degree of similarity between emerged seedlings and mature vegetation in both the treated and in the untreated soils, which was probably a consequence of the dominance of resprouting species. Some consequences for the management of

  1. Drought-Induced Leaf Proteome Changes in Switchgrass Seedlings

    Directory of Open Access Journals (Sweden)

    Zhujia Ye

    2016-08-01

    Full Text Available Switchgrass (Panicum virgatum is a perennial crop producing deep roots and thus highly tolerant to soil water deficit conditions. However, seedling establishment in the field is very susceptible to prolonged and periodic drought stress. In this study, a “sandwich” system simulating a gradual water deletion process was developed. Switchgrass seedlings were subjected to a 20-day gradual drought treatment process when soil water tension was increased to 0.05 MPa (moderate drought stress and leaf physiological properties had expressed significant alteration. Drought-induced changes in leaf proteomes were identified using the isobaric tags for relative and absolute quantitation (iTRAQ labeling method followed by nano-scale liquid chromatography mass spectrometry (nano-LC-MS/MS analysis. Additionally, total leaf proteins were processed using a combinatorial library of peptide ligands to enrich for lower abundance proteins. Both total proteins and those enriched samples were analyzed to increase the coverage of the quantitative proteomics analysis. A total of 7006 leaf proteins were identified, and 257 (4% of the leaf proteome expressed a significant difference (p < 0.05, fold change <0.6 or >1.7 from the non-treated control to drought-treated conditions. These proteins are involved in the regulation of transcription and translation, cell division, cell wall modification, phyto-hormone metabolism and signaling transduction pathways, and metabolic pathways of carbohydrates, amino acids, and fatty acids. A scheme of abscisic acid (ABA-biosynthesis and ABA responsive signal transduction pathway was reconstructed using these drought-induced significant proteins, showing systemic regulation at protein level to deploy the respective mechanism. Results from this study, in addition to revealing molecular responses to drought stress, provide a large number of proteins (candidate genes that can be employed to improve switchgrass seedling growth and

  2. Drought-Induced Leaf Proteome Changes in Switchgrass Seedlings.

    Science.gov (United States)

    Ye, Zhujia; Sangireddy, Sasikiran; Okekeogbu, Ikenna; Zhou, Suping; Yu, Chih-Li; Hui, Dafeng; Howe, Kevin J; Fish, Tara; Thannhauser, Theodore W

    2016-01-01

    Switchgrass (Panicum virgatum) is a perennial crop producing deep roots and thus highly tolerant to soil water deficit conditions. However, seedling establishment in the field is very susceptible to prolonged and periodic drought stress. In this study, a "sandwich" system simulating a gradual water deletion process was developed. Switchgrass seedlings were subjected to a 20-day gradual drought treatment process when soil water tension was increased to 0.05 MPa (moderate drought stress) and leaf physiological properties had expressed significant alteration. Drought-induced changes in leaf proteomes were identified using the isobaric tags for relative and absolute quantitation (iTRAQ) labeling method followed by nano-scale liquid chromatography mass spectrometry (nano-LC-MS/MS) analysis. Additionally, total leaf proteins were processed using a combinatorial library of peptide ligands to enrich for lower abundance proteins. Both total proteins and those enriched samples were analyzed to increase the coverage of the quantitative proteomics analysis. A total of 7006 leaf proteins were identified, and 257 (4% of the leaf proteome) expressed a significant difference (p 1.7) from the non-treated control to drought-treated conditions. These proteins are involved in the regulation of transcription and translation, cell division, cell wall modification, phyto-hormone metabolism and signaling transduction pathways, and metabolic pathways of carbohydrates, amino acids, and fatty acids. A scheme of abscisic acid (ABA)-biosynthesis and ABA responsive signal transduction pathway was reconstructed using these drought-induced significant proteins, showing systemic regulation at protein level to deploy the respective mechanism. Results from this study, in addition to revealing molecular responses to drought stress, provide a large number of proteins (candidate genes) that can be employed to improve switchgrass seedling growth and establishment under soil drought conditions (Data are

  3. Soil Temperature Dependent Growth of Cotton Seedlings Before Emergence

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Soil temperature is an important variable governing plant growth and development.Studies were conducted under laboratory conditions to determine the effect of soil temperature on root and shoot growth of cotton during emergence.Cotton seedlings were grown for 192 h at 20,32 and 38℃ in soil packed in 300 mm long and 50 mm diameter cylinders.The data indicated that the longest roots(173 ram)as well as shoots(152 mm)were recorded at 32 ℃ followed by 20 (130 mm root and 82 mm shoot)and 38℃(86 mm root and 50 mm shoot).Roots grown at 20 and 38 ℃ were 20% and 50% shorter,respectively,than those grown at 32℃ after 192 h.Roots and shoots exhibited the lowest length and dry biomass at 38℃.Shoot lengths grown at 20(74 ram)and 38℃(51 mm)were 44% and 61% shorter than those grown at 32℃(131 mm)after 180 h growth period,respectively.Growth at all three temperatures followed a similar pattern.Initially there was a linear growth phase followed by the reduction or cessation of growth.Time to cessation of growth varied with temperature and decreased faster at higher temperatures.Sowing of cotton should be accomlplished before seedbed reaches a soil temperature(≥38℃)detrimental for emergence.Further,the seedbeds should be capable of providing sufficient moisture and essential nutrients for emerging seedling before its seed reserves are exhausted to enhance seedling establishment in soil.

  4. Improving Acacia auriculiformis seedlings using microbial inoculant (Beneficial Microorganisms)

    Institute of Scientific and Technical Information of China (English)

    Bayezid M. Khan; M.K. Hossain; M.A.U. Mridha

    2014-01-01

    A microbial inoculant, known as effective microorganisms (EM), was applied to determine its efficacy on seed germination and seedling growth in the nursery of Acacia auriculiformis A Cunn. ex Benth. The seedlings were grown in a mixture of sandy soil and cow dung (3:1) and kept in polybags;EM was poured at different concentra-tions (0.1%, 0.5%, 1%, 2%, 5% and 10%). Seed germination rate and growth parameters of seedlings - shoot and root lengths, fresh and dry weights of shoots and roots, vigor, volume, and quality indices and stur-diness - were measured. The nodulation status influenced by EM was also observed, along with the measurement of pigment contents in leaves. The highest germination rate (72%) was observed in 2% EM solution while the lowest (55%) was found in control treatment. The highest shoot and root lengths (30.6 cm and 31.2 cm respectively) were recorded in 2%EM and were significantly (p <0.05) different from control. Both fresh and dry weights of shoots were maximum (8.66 g and 2.99 g respectively) in 2% EM, whereas both fresh and dry weights of root were maximum (2.56 g and 1.23 g respectively) in 5%EM solution. Although the highest vigor index, volume index, and sturdiness (4450, 628 and 67.5 respec-tively) were found in 2% EM, the highest quality index (0.455) was found in 5%EM solution. The nodule number was higher at a very low (0.5%) concentration of EM but it normally decreased with the increase of concentration. The contents of chlorophyll a, chlorophyll b, and caro-tenoid were maximum (43.26 mg⋅L-1, 13.56 mg⋅L-1and 17.99 mg⋅L-1 respectively) in 2%EM. Therefore, low concentration of EM (up to 2%)can be recommended for getting maximum seed germination and seed-ling development of A. auriculiformis in the nursery.

  5. EFFECTS OF PISOLITHUS TINCTORIUS AND LACCARIA FRATERNA ON THE GROWTH AND MYCORRfflZAL DEVELOPMENT OF PINUSPATULA SEEDLINGS

    Directory of Open Access Journals (Sweden)

    M. SUDHAKARA REDDY

    1995-01-01

    Full Text Available Vegetative inoculum of Pisolithus tinctorius and Laccariafraterna were inoculated to Pinuspatula seedlings grown in both steam sterilized and unsterilized shola soil. After 4 months of seedling growth, 10 seedlings from each treatment were harvested and various growth parameters were studied. Inoculation of these two fungi resulted in the production of ectomycorrhizas and increase in growth of P. patula seedlings when compared to uninoculated seedlings. Laccariafraterna inoculated seedlings showed more number of mycorrhizas than P. tinctorius inoculated seedlings at the end of one year. Both these fungi poorly colonized the root system in both soil treatments. There was no significant difference between these two fungi in improving the seedling growth in the nursery.

  6. Effect of Ionic and Chelate Assisted Hexavalent Chromium on Mung Bean Seedlings (Vigna radiata L. wilczek. var k-851 During Seedling Growth

    Directory of Open Access Journals (Sweden)

    Mohanty, Monalisa

    2013-04-01

    Full Text Available The effect of Cr+6 with and without chelating agents were assessed in mung bean seedlings grown hydroponically. It was noted that the growth parameters showed a declining trend with increasing Cr+6 concentrations without chelate application. Among the seedlings grown with chelated chromium complexes, Cr+6–DTPA (10µM showed highest growth rate of roots as well as shoots. At higher concentration of Chromium i.e. Cr+6 (100µM, there exhibited high chlorophyll content in mung bean leaves where the seedlings showed stunted growth. The seedlings treated without and with chelated chromium complexes showed increased proline content as compared to control. The enzymatic study showed that, the catalase activity was maximum in shoots as compared to roots and the reverse is true in the case of peroxidase activity i.e. the roots showed higher value than that of the shoots.

  7. CROWN GALL INCIDENCE: SEEDLING PARADOX WALNUT ROOTSTOCK VERSUS OWN-ROOTED ENGLISH WALNUT TREES

    Science.gov (United States)

    Seedling Paradox (Juglans hindsii x J. regia) has been the rootstock of choice for English walnut in California because of its vigor and greater tolerance of wet soil conditions. However, seedling Paradox rootstock is highly susceptible to crown gall, a disease caused by the soil-borne bacterium Agr...

  8. A systems genetics study of seed quality and seedling vigour in Brassica rapa

    NARCIS (Netherlands)

    Basnet, R.K.

    2015-01-01

    Summary Seed is the basic and most critical input for seed propagated agricultural crops: seed quality and seedling vigour determine plant establishment, growth and development in both natural and agricultural ecosystems. Seed quality and seedling vigour are mainly determined by the

  9. [Relationships between seed size and seedling growth strategy of herbaceous plant: a review].

    Science.gov (United States)

    Wu, Gao-lin; Du, Guo-zhen

    2008-01-01

    Seed size and seedling recruitment strategy are of importance in the life-history strategy of plant. In this paper, the current ecological researches at home and aboard on the relationships between seed size and seedling growth were reviewed from the aspects of the effects of seed size on seed germination and seedling emergence, the relationships between seed size and seedling growth traits, and the relationships between seed size and seedling survival and competition ability. Some suggestions on future researches in this field were put forward. There were likely different relationships between seed size and seedling growth in different microenvironments and vegetation types, and the effects of seed size on seedling growth could result in different contributions of different seed-size species to the seedling recruitment of vegetation. The large-scale community level and the small-scale intra- and inter-species level researches on this issue should be strengthened, which would have significance for the recruitment and renewing of natural vegetation.

  10. Development of a doorframe-typed swinging seedling pick-up device for automatic field transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Han, H.; Mao, H.; Hu, J.; Tian, K.

    2015-07-01

    A doorframe-typed swing seedling pick-up device for automatic field transplanters was developed and evaluated in a laboratory. The device, consisting of a path manipulator and two grippers, can move the pins slowly to extract seedlings from the tray cells and return quickly to the pick-up point for the next extraction. The path manipulator was constructed with the creative design of type-Ⅱ mechanism combination in series. It consists of an oscillating guide linkage mechanism and a grooved globoidal cam mechanism. The gripper is a pincette-type mechanism using the pick-up pins to penetrate into the root mass for seedling extraction. The dynamic analysis of the designed seedling pick-up device was simulated with ADAMS software. Being the first prototype, various performance tests under local production conditions were conducted to find out the optimal machine operation parameters and transplant production conditions. As the gripper with multiple fine pins was moved by the swing pick-up device, it can effectively complete the transplanting work cycle of extracting, transferring, and discharging a seedling. The laboratory evaluation showed that the pick-up device equipped with two grippers can extract 80 seedlings/min with a 90% success and a 3% failure in discharging seedlings, using 42-day-old tomato plantlets. The quality of extracting seedlings was satisfactory. (Author)

  11. Root carbon reserve dynamics in aspen seedlings: does simulated drought induce reserve limitation?

    Science.gov (United States)

    Galvez, David A; Landhäusser, S M; Tyree, M T

    2011-03-01

    In a greenhouse study we quantified the gradual change of gas exchange, water relations and root reserves of aspen (Populus tremuloides Michx.) seedlings growing over a 3-month period of severe water stress. The aim of the study was to quantify the complex interrelationship between growth, water and gas exchange, and root carbon (C) dynamics. Various growth, gas exchange and water relations variables in combination with root reserves were measured periodically on seedlings that had been exposed to a continuous drought treatment over a 12-week period and compared with well-watered seedlings. Although gas exchange and water relations parameters significantly decreased over the drought period in aspen seedlings, root reserves did not mirror this trend. During the course of the experiment roots of aspen seedlings growing under severe water stress showed a two orders of magnitude increase in sugar and starch content, and roots of these seedlings contained more starch relative to sugar than those in non-droughted seedlings. Drought resulted in a switch from growth to root reserves storage which indicates a close interrelationship between growth and physiological variables and the accumulation of root carbohydrate reserves. Although a severe 3-month drought period created physiological symptoms of C limitation, there was no indication of a depletion of root C reserve in aspen seedlings.

  12. Response of germinating barley seeds to Fusarium graminearum: The first molecular insight into Fusarium seedling blight

    DEFF Research Database (Denmark)

    Yang, Fen; Svensson, Birte; Finnie, Christine

    2011-01-01

    Fusarium seedling blight in cereals can result in significant reductions in plant establishment but has not received much attention. The disease often starts during seed germination due to sowing of the seeds infected by Fusarium spp. including Fusarium graminearum. In order to gain the first...... provides the first molecular insight into Fusarium seedling blight....

  13. Growth of transplanted timber species seedlings in the south of the Colombian Amazon: A preliminary study

    NARCIS (Netherlands)

    Gruezmacher, M.; Duivenvoorden, J.F.

    2008-01-01

    Two commonly used timber species in the area of Amacayacu National Park (Quararibea sp. and Minquartia guianensis) were selected to develop an experiment that compared the early performance of seedlings in mature and old secondary forest. We transplanted seedlings of these species into mature and

  14. Seedling regeneration on decayed pine logs after the deforestation events caused by pine wilt disease

    Directory of Open Access Journals (Sweden)

    Y. Fukasawa

    2016-12-01

    Full Text Available Coarse woody debris (CWD forms an important habitat suitable for tree seedling establishment, and the CWD decay process influences tree seedling community. In Japan, a severe dieback of Pinus densiflora Sieb. & Zucc. caused by pine wilt disease (PWD damaged huge areas of pine stands but creates huge mass of pine CWD. It is important to know the factors influencing seedling colonization on pine CWD and their variations among geographical gradient in Japan to expect forest regeneration in post-PWD stands. I conducted field surveys on the effects of latitude, climates, light condition, decay type of pine logs, and log diameter on tree seedling colonization at ten geographically distinct sites in Japan. In total, 59 tree taxa were recorded as seedlings on pine logs. Among them, 13 species were recorded from more than five sites as adult trees or seedlings and were used for the analyses. A generalized linear model showed that seedling colonization of Pinus densiflora was negatively associated with brown rot in sapwood, while that of Rhus trichocarpa was positively associated with brown rot in heartwood. Regeneration of Ilex macropoda had no relationships with wood decay type but negatively associated with latitude and MAT, while positively with log diameter. These results suggested that wood decay type is a strong determinant of seedling establishment for certain tree species, even at a wide geographical scale; however, the effect is tree species specific.

  15. Fertility-dependent effects of ectomycorrhizal fungal communities on white spruce seedling nutrition

    Science.gov (United States)

    Alistair J. H. Smith; Lynette R. Potvin; Erik A. Lilleskov

    2015-01-01

    Ectomycorrhizal fungi (EcMF) typically colonize nursery seedlings, but nutritional and growth effects of these communities are only partly understood. To examine these effects, Picea glauca seedlings collected from a tree nursery naturally colonized by three dominant EcMF were divided between fertilized and unfertilized treatments. After one...

  16. Development of a doorframe-typed swinging seedling pick-up device for automatic field transplantation

    Directory of Open Access Journals (Sweden)

    Han Luhua

    2015-06-01

    Full Text Available A doorframe-typed swing seedling pick-up device for automatic field transplanters was developed and evaluated in a laboratory. The device, consisting of a path manipulator and two grippers, can move the pins slowly to extract seedlings from the tray cells and return quickly to the pick-up point for the next extraction. The path manipulator was constructed with the creative design of type-II mechanism combination in series. It consists of an oscillating guide linkage mechanism and a grooved globoidal cam mechanism. The gripper is a pincette-type mechanism using the pick-up pins to penetrate into the root mass for seedling extraction. The dynamic analysis of the designed seedling pick-up device was simulated with ADAMS software. Being the first prototype, various performance tests under local production conditions were conducted to find out the optimal machine operation parameters and transplant production conditions. As the gripper with multiple fine pins was moved by the swing pick-up device, it can effectively complete the transplanting work cycle of extracting, transferring, and discharging a seedling. The laboratory evaluation showed that the pick-up device equipped with two grippers can extract 80 seedlings/min with a 90% success and a 3% failure in discharging seedlings, using 42-day-old tomato plantlets. The quality of extracting seedlings was satisfactory.

  17. An improved method for seed-bank analysis : Seedling emergence after removing the soil by sieving

    NARCIS (Netherlands)

    ter Heerdt, G.N.J.; Bekker, R.M.; Bakker, J.P.; Verweij, G.L.

    1. The seedling emergence method for assessing the size of the seed bank is improved by washing soil samples on a fine sieve and spreading the thus concentrated samples in a 3-5 mm thick layer on sterilized potting compost. 2. The method largely increases the number of seedlings that emerge as

  18. Energy biomass tree seedling production study. Fuels from woody biomass. Progress report, September 1978-January 1980

    Energy Technology Data Exchange (ETDEWEB)

    Foote, K.R.

    1980-03-01

    The research to date has centered around the establishment of baseline growing conditions for a number of species of tree seedlings, primarily deciduous hardwoods. As these baseline conditions were established for each specie, the shoot and root environments were manipulated in an attempt to establish techniques to increase seedling growth and reduce production times. Seedlings were outplanted in an attempt to establish baseline survival rates for seedlings grown in totally controlled environments. Studies to determine the optimum container for tree seedling production have been run and will continue as other containers are identified and made available. The most significant of the research results has been in the maximization of seedling growth. Seedling production times have been decreased in some species by as much as 50% under the baseline production times. Controlled environment production techniques provide for plant densities as high as 144 seedlings per square foot of growing space. Investigations of growing media indicate a significant species specific responses. Preliminary results of outplanting indicate survival rates as high as 90% plus.

  19. An improved method for seed-bank analysis : Seedling emergence after removing the soil by sieving

    NARCIS (Netherlands)

    ter Heerdt, G.N.J.; Bekker, R.M.; Bakker, J.P.; Verweij, G.L.

    1996-01-01

    1. The seedling emergence method for assessing the size of the seed bank is improved by washing soil samples on a fine sieve and spreading the thus concentrated samples in a 3-5 mm thick layer on sterilized potting compost. 2. The method largely increases the number of seedlings that emerge as compa

  20. Two-year results of herbicide released, naturally-regenerated bottomland cherrybark and shumard oak seedlings

    Science.gov (United States)

    John F., Jr. Thompson; Larry E. Nix

    1995-01-01

    After clearcuting in bottomlands, oak seedlings that naturally regenerate are often overtopped by woody pioneer species, sprouts and herbaceous material. To improve the competitive status of three- to four-year-old oak seedlings in two bottomland stands in South Carolina, several herbicides and methods of application were used to kill and/or stunt the overtopping...

  1. The changes of glutation reductase activity in maize seedlings under heavy metals and herbicide frontjere influence

    Directory of Open Access Journals (Sweden)

    V. S. Bilchuk

    2005-01-01

    Full Text Available In modelling experiment joint action of heavy metal ions (lead, cadmium and cloroacetanilide herbicide frontjere on glutationreductase activity in maize seedlings at initial stages of ontogenesis was investigated. The increasing of enzyme activity in a sprouting grain at herbicide and ions of lead and cadmium presence and variation of enzyme activity in seedlings were established at joint action of toxicants.

  2. Seedling establishment and physiological responses to temporal and spatial soil moisture changes

    Science.gov (United States)

    Jeremy Pinto; John D. Marshall; Kas Dumroese; Anthony S. Davis; Douglas R. Cobos

    2016-01-01

    In many forests of the world, the summer season (temporal element) brings drought conditions causing low soil moisture in the upper soil profile (spatial element) - a potentially large barrier to seedling establishment. We evaluated the relationship between initial seedling root depth, temporal and spatial changes in soil moisture during drought after...

  3. Effect of nitrogen fertilization and seedling density on fine rice yield in Faisalabad, Pakistan

    Directory of Open Access Journals (Sweden)

    Ehsanullah, Khawar Jabran, Ghulam Asghar

    2012-11-01

    Full Text Available Rice seedlings density per hill and optimal nitrogen fertilization exercises a strong influence on rice growth and grain yield due to competitive effects both on the vegetative and reproductive development. Present study was conducted to explore the possible role of nitrogen fertilizer and seedlings density on rice kernel yield and yield contributing factors. Three nitrogen (N rates viz. 75, 100 and 125 kg ha-1 and four seedling densities (1, 2, 3 and 4 seedlings hill-1 were tested in the study. Panicle length, number of branches per panicle and kernels per panicle remained unaffected at varying levels of N and rice seedlings per hill. Two, 3 and 4 seedlings per hill along with 100 and 125 kg N ha-1 resulted in maximum rice kernel yield and harvest index due to enhanced number of panicle bearing tillers and 1000-kernel weight. While application of N at 75 kg ha-1 along with one seedling per hill revealed the poorest results with respect to 1000-kernel weight, panicle bearing tillers per hill and the kernel yield of rice. In crux, two seedlings hill-1 at 100 kg N ha-1 proved to be the best combination for maximizing the rice yield in the Faisalabad area of Pakistan.

  4. Development and plasticity of endangered shrub Lindera melissifolia (Lauraceae) seedlings under contrasting light regimes

    Science.gov (United States)

    Brian R Lockhart; Emile S Gardiner; Theran Stautz; Theodor D. Leininger

    2012-01-01

    Lindera melissifolia (Walt.) Blume seedlings were raised in a growth chamber to determine the effects of light availability on shoot growth pattern, and basic leaf and stem growth. Lindera melissifolia seedlings exhibited a sympodial shoot growth pattern for 3 months following emergence from the soil medium, but this pattern was characterized by a reduction in leaf...

  5. Morphotypes of Dactylorhiza incarnata (L. Soу (Orchidaceae seedlings in vitro

    Directory of Open Access Journals (Sweden)

    Oleg A. Marakaev

    2012-03-01

    Full Text Available The morphotypes, linear parameters and morphological features for Dactylorhiza incarnata seedlings in vitro have been set. The uneven growth and development of seedlings in depending from the location and degree of contact with the medium have been identified.

  6. Chilling Tolerance and Physiological Parameters as Influenced by Grafting in Watermelon Seedlings

    Institute of Scientific and Technical Information of China (English)

    LIU Hui-ying; ZHU Zhu-jun; LU Guo-hua; QIAN Qiong-qiu

    2003-01-01

    The influences of different rootstocks on chilling tolerance and physiological parameters in wa-termelon seedlings have been studied. The results showed that grafting improved the chilling tolerance. Com-pared with own-rooted watermelon seedlings, the grafted watermelon seedlings had lower chilling injury index,lower electrolytic leakage (%), lower malondialdehyde (MDA) content, higher chlorophyll and proline con-tent, and higher activities of superoxide dismutase (SOD), ascorbate peroxidase (AsA-POD) and de-hydroascorbate reductase (DR) in the leaves under iow temperature stress. There was a considerable differenceof chilling tolerance among different grafted watermelon seedlings due to the difference of rootstock chillingtolerance. After low temperature treatment, the grafted seedling with higher chilling tolerance had lower elec-trolytic leakage ( %), lower MDA content, higher proline content and higher activities of SOD, AsA-POD andDR in the leaves compared with the grafted seedling with weaker chilling tolerance. From these, we could con-clude that chilling tolerance of watermelon seedlings may be related to higher antioxidative ability and mem-brane stability in the plants. The chilling tolerance of grafted seedling could be properly evaluated by compre-hensive physiological indexes but not a single physiological index.

  7. Pseudomonas fluorescens and Pseudomonas putida for Promoting Growth of Jatropha curcas Seedling Root

    Directory of Open Access Journals (Sweden)

    Sri Sumarsih

    2012-05-01

    Full Text Available Pseudomonas fluorescens and P. putida are Plant Growth Promoting Rhizobacteria (PGPR that can produce growth hormone. The objective of this study is to know the effects of those two combined species of PGPR on seedling root growth of Jatropha curcas. The condition of the seedling root determines the success of dry land cultivation. The root which has wider coverage, is larger in number, and is bigger in diameter makes seedling more resistant to stress in dry land environment. In the experiment, two kinds of plant materials are used for seedling, the Jatropha seed and stem material, which are treated in a mixed culture of PGPR. For the Jatropha seed, this mixed culture of PGPR is given at the same time of cultivating the sprout on the seedling medium. For the stem cutting, the PGPR is poured in together during the first watering of the seedling cultivation medium. In the fourthweek, the observed growth parameters are root length, root diameter, primary and secondary lateral root numbers, Root Length Density (RLD, Frequency of Lateral Root (FLR, and Specific Root Length (SRL. These data are analyzed using analysis of variant with DMRT test at 0.05 level of significance. The result of this study shows that PGPR tend to reduce FLR values on the seedling root made from seeds. On the seedling root made from stem cutting, PGPR increase the root length, primary and secondary lateral root numbers, root diameter, FLR and SRL values as well.

  8. Maize white seedling 3 results from disruption of homogentisate solanesyl transferase

    Science.gov (United States)

    Maize white seedling 3 (w3) has served as a model albino-seedling mutant since its discovery in 1923. We show here that the w3 phenotype is caused by disruptions in homogentisate solanesyl transferase (HST), an enzyme that catalyzes the committed step in plastoquinone-9 (PQ9) biosynthesis. This re...

  9. Effects of Different Quantities of Tea-leaf Wormcast Substrate on the Growth of Tomato Seedling

    Directory of Open Access Journals (Sweden)

    YANG Wei

    2015-08-01

    Full Text Available The tomato seedling experiment was conducted to investigate the effect of substrate on the tomato seedling growth from five proportions of tea-leaf wormcast to peat, perlite and vermiculite, namely treatment I(1:5:2:2, treatment Ⅱ(2:4:2:2, treatment Ⅲ(3:3:2:2, treatment Ⅳ(4:2:2:2, treatment Ⅴ(6:0:2:2, respectively. The botany properties and characters of tomato seedling were observed to discuss the application effect of tea-leaf wormcast substrate. The results showed that in all treatments of the compound substrate of tea-leaf wormcast, except of treatment I, the tomato seedling indexes were superior to the control treatments(conventional seedling substrate in market, and the treatments Ⅳ had the best effect, followed by treatment Ⅴ. With the increasing proportion of tea-leaf wormcast, the plant height, stem diameter, SPAD value, and root morphology index of tomato seedlings firstly increased, and then decreased obviously. The substrate with the appropriate proportion of tea-leaf wormcast could obviously improve the quality of tomato seedlings, and the treatment Ⅳ was the best, which could be recommended for the actual production of tomato seedling.

  10. Recovery of l-year-old loblolly pine seedlings from simulated browse damage

    Science.gov (United States)

    Michael G. Shelton; Michael D. Cain

    2002-01-01

    Loblolly pine (Pinus taeda L.) seedlings are frequently browsed by a wide variety of animals during the first few years of their development. Although anecdotal observations indicate that the potential for seedling recovery is good, there is little quantitative information on the factors affecting the recovery process. Thus, we conducted a study to...

  11. Tree invasion in a semi-arid savanna in Zimbabwe : seedling recruitment of Acacia karroo

    NARCIS (Netherlands)

    Chirara, C. (Chipangura)

    2002-01-01

    In this thesis Chirara reports on his study on the competitive interaction between savanna grasses and young tree seedlings of Acacia karroo, from hereon indicated as ' Acacia seedlings' . Acacia is one of the tree species that dominates savanna grassland in situations of overgrazing (bush encroachm

  12. Tree invasion in a semi-arid savanna in Zimbabwe : seedling recruitment of Acacia karroo

    NARCIS (Netherlands)

    Chirara, C. (Chipangura)

    2001-01-01

    In this thesis Chirara reports on his study on the competitive interaction between savanna grasses and young tree seedlings of Acacia karroo, from hereon indicated as ' Acacia seedlings' . Acacia is one of the tree species that dominates savanna grassland in situations of overgrazing (bush

  13. The role of plant water relations in achieving and maintaining the target seedling

    Science.gov (United States)

    John G. Mexal; Nabil Khadduri

    2011-01-01

    Water management is one of the most important factors in achieving the target seedling. Water is required for cell growth, nutrient transport, cooling through transpiration, and in small amounts for the photosynthetic reaction. Furthermore, judicious use of limiting water availability during the hardening phase can induce budset and increase seedling cold hardiness....

  14. Seedling regeneration on decayed pine logs after the deforestation events caused by pine wilt disease

    Directory of Open Access Journals (Sweden)

    Y. Fukasawa

    2016-12-01

    Full Text Available Coarse woody debris (CWD forms an important habitat suitable for tree seedling establishment, and the CWD decay process influences tree seedling community. In Japan, a severe dieback of Pinus densiflora Sieb. & Zucc. caused by pine wilt disease (PWD damaged huge areas of pine stands but creates huge mass of pine CWD. It is important to know the factors influencing seedling colonization on pine CWD and their variations among geographical gradient in Japan to expect forest regeneration in post-PWD stands. I conducted field surveys on the effects of latitude, climates, light condition, decay type of pine logs, and log diameter on tree seedling colonization at ten geographically distinct sites in Japan. In total, 59 tree taxa were recorded as seedlings on pine logs. Among them, 13 species were recorded from more than five sites as adult trees or seedlings and were used for the analyses. A generalized linear model showed that seedling colonization of Pinus densiflora was negatively associated with brown rot in sapwood, while that of Rhus trichocarpa was positively associated with brown rot in heartwood. Regeneration of Ilex macropoda had no relationships with wood decay type but negatively associated with latitude and MAT, while positively with log diameter. These results suggested that wood decay type is a strong determinant of seedling establishment for certain tree species, even at a wide geographical scale; however, the effect is tree species specific.

  15. Fungicide seed treatments for evaluating the corn seedling disease complex following a winter rye cover crop

    Science.gov (United States)

    Seed treatments have been used to manage corn seedling diseases since the 1970’s and they contain a combination of active ingredients with specificity towards different pathogens. We hypothesized that using different seed treatment combinations and assessing seedling disease incidence and severity ...

  16. Effect of apical meristem clipping on carbon allocation and morphological development of white oak seedlings

    Science.gov (United States)

    Paul P. Kormanik; Shi-Jean S. Sung; T.L. Kormanik; Stanley J. Zarnoch

    1994-01-01

    Seedlings from three open-pollinated half-sib white oak seedlots were clipped in mid-July and their development was compared to nonclipped controls after one growing season.In general when data were analyzed by family, clipped seedlings were significantly less desirable in three to six of the eight variables tested.Numerically, in all families seedlots, the clipped...

  17. Inhibition of seedling survival under Rhodendron maximum (Ericaceae): could allelopathy be a cause?

    Science.gov (United States)

    Erik T. Nilsen; John F. Walker; Orson K. Miller; Shawn W. Semones; Thomas T. Lei; Barton D. Clinton

    1999-01-01

    In the Southern Appalachian Mountains a subcanopy species, Rhododendron maximum, inhibits the establishment and survival of canopy tree seedlings. One of the mechanisms by which seedlings could be inhibited is an allelopathic effect of decomposing litter or leachate from the canopy of R. maximum (R.m.) on seed germination, root...

  18. Variation among black walnut seedling families in resistance to competition and allelopathy

    Science.gov (United States)

    George Rink; J.W. Van Sambeek

    1985-01-01

    Of three environmental variables affecting black walnut seedling establishment, moisture stress overshadowed the effects of fescue leachate and fertilizer. Interactions between moisture stress and family and between fescue leachate and moisture stress for both seedling height and dry weight suggested that selection for tolerance to moisture stress is possible, whereas...

  19. Formula for Determining Number of Basic Seedlings at Scattered-Planting with Seedling Dry-Raised on Plastic Trays in Double-Season Rice

    Institute of Scientific and Technical Information of China (English)

    PAN Xiao-hua; CHEN Xiao-rong; YANG Fu-sun

    2006-01-01

    The tiller emergence in seedling nursery beds and field, and panicle formation in the field were investigated under scattered-planting with seedling dry-raised on plastic trays in double-season rice. A significant difference was noted in the non-synchronously-emerged tillers (the tillers that formed from latent buds and did not emerge following the normal tillering law on seedling nursery beds and recovered to grow after scattered-planting or transplanting) as well as the percentage of the available synchronously-emerged tillers between seedlings raised on plastic trays under dry-land conditions (DPT) and seedlings raised on nursery beds under wetland conditions (WB). The seedlings under DPT had some non-synchronously-emerged tillers, but those under WB had not. Therefore, the traditional formula for determining the number of rice seedlings was improved, and the formula for determining the number of basic seedlings under scattered planting with DPT in double-season rice was introduced. For early rice, it was X=YI{(1+t1r1)[1+(N-n-SN)Rr2]+(SN-3-t1)R2r5}, and for late rice, it was X=YI{(1+t1r1)[1+(N-n-SN)Rr2]+(N-n-SN-3)Rr2R1r3+(SN-3-t1)R2r5}. Where, X represents reasonable number of basic seedlings per unit area at scattered-planting; Y,number of fitting panicles per unit area; t1, total number of tillers per plant; r1, percentage of the total available tillers; N, total number of leaves of the main culm; n, total number of elongated internodes in the main culm; SN, seedling leaf ages at scattered-planting; R,percentage of the primary tillers emerged in available node-position; r2, percentage of the available primary tillers; R1, percentage of the secondary tillers in the field (except the secondary tillers of the seedlings); r3, percentage of the available secondary tillers; R2,percentage of the asynchronously-emerged tillers after scattered-planting; r5, percentage of the available non-synchronously-emerged tillers after scattered-planting.

  20. Effects of filamentous macroalgae on growth and survival of eelgrass, Zostera marina, seedlings

    DEFF Research Database (Denmark)

    Rasmussen, Jonas; Krause-Jensen, Dorte; Olesen, Birgit

    the mat and periods of anoxia in the lower parts can possibly be followed by release of sulphide from the sediments. We assessed the impact of algae mats on seedling performance and evaluated the relative importance of light attenuation and low oxygen concentrations for seedling growth and survival based...... and effects on seedling growth can thus be attributed to reduced light caused by shading of the algae. Generally, the seedlings are shown to be robust to short-term reductions in light availability, but further experiments are needed to elucidate the relative contributions of reduced light vs. anoxic...... on eelgrass seedling performance. The covering of eelgrass shoots by algae decreases the light availability and may hamper the diffusive movement of oxygen, inorganic carbon and nutrients to and from the shoots. Moreover, the high productivity of the algae can result in large diurnal oxygen variations within...

  1. Development of seedlings of watermelon cv. Crimson Sweet irrigated with biosaline water

    Directory of Open Access Journals (Sweden)

    José E. S. B. da Silva

    2015-09-01

    Full Text Available ABSTRACTThe limited access and the scarcity of good quality water for agriculture are some of the major problems faced in agricultural areas, particularly in arid and semiarid regions. The aim of this study was to evaluate the quality of watermelon seedlings (cv. Crimson Sweet, irrigated with different concentrations of biosaline water of fish culture. The experimental design was completely randomized with five treatments, corresponding to biosaline water at different concentrations (0, 33, 50, 67 and 100%, and four replicates of 108 seedlings. Watermelon seeds were sown in plastic trays filled with commercial substrate and irrigated with different solutions of biosaline water. Seedlings were harvested for biometric analysis at 14, 21 and 28 days after sowing. The use of biosaline water did not affect emergence and establishment of seedlings until 14 days after sowing, the period recommended for transplantation. However, the use of biosaline water affected the development of seedlings with longer exposure time.

  2. Increased Biomass of Nursery-Grown Douglas-Fir Seedlings upon Inoculation with Diazotrophic Endophytic Consortia

    Directory of Open Access Journals (Sweden)

    Zareen Khan

    2015-10-01

    Full Text Available Douglas-fir (Pseudotsuga menziesii seedlings are periodically challenged by biotic and abiotic stresses. The ability of endophytes to colonize the interior of plants could confer benefits to host plants that may play an important role in plant adaptation to environmental changes. In this greenhouse study, nursery-grown Douglas-fir seedlings were inoculated with diazotrophic endophytes previously isolated from poplar and willow trees and grown for fifteen months in nutrient-poor conditions. Inoculated seedlings had significant increases in biomass (48%, root length (13% and shoot height (16% compared to the control seedlings. Characterization of these endophytes for symbiotic traits in addition to nitrogen fixation revealed that they can also solubilize phosphate and produce siderophores. Colonization was observed through fluorescent microscopy in seedlings inoculated with gfp- and mkate-tagged strains. Inoculation with beneficial endophytes could prove to be valuable for increasing the production of planting stocks in forest nurseries.

  3. Influence of irrigation method and container type on Northern red oak seedling growth and media electrical conductivity

    Science.gov (United States)

    Anthony S. Davis; Douglass F. Jacobs; Ronald P. Overton; R. Kasten Dumroese

    2008-01-01

    Container production of hardwood seedlings has not been extensively practiced. Efficient nursery production of hardwood seedlings in containers can be limited by formation of a broad foliar canopy, which limits irrigation uniformity. This study was established to investigate suitability of subirrigation, a method of irrigating seedlings from the container base that...

  4. Metabolite profiling of Ricinus communis germination at different temperatures provides new insights into thermo-mediatedrequirements for successful seedling establishment

    NARCIS (Netherlands)

    Ribeiro de Jesus, P.R.; Willems, L.A.J.; Mutimawurugo, M.C.; Fernandez, L.G.; Castro, De R.D.; Ligterink, W.; Hilhorst, H.W.M.

    2015-01-01

    Ricinus communis seeds germinate to a high percentage and faster at 35¿C than at lower temperatures, butwith compromised seedling establishment. However, seedlings are able to cope with high temperaturesat later stages of seedling establishment if germination occurred at lower temperatures. Our

  5. [Allelopathy of different plants on wheat, cucumber and radish seedlings].

    Science.gov (United States)

    Shen, Huimin; Guo, Hongru; Huang, Gaobao

    2005-04-01

    By means of bioassay in laboratory and field, this paper studied the allelopathy of 18 kinds of plants in Gansu Province on the seedlings of wheat, cucumber and radish. The results showed that the aqueous extract of the stems and leaves of Artemisia annua, Solanum nigrum and Datura stramonium had the strongest allelopathy on test receptor plants, and their synthetic inhibitory effect (SE) was 47.66%, 32.89% and 26.63%, respectively. The SE of Xanthium sibiricum, Portulaca oleraca, Cephalanoplos segetum, and Chenopodium album was 21.71%, 20.93%, 20.83% and 20.2%, respectively, while Vicia amoena (SE 3.5%), Setaria viridis (SE 2.2%), and Cymamchum chinense (SE 1.97%) had a weaker allelopathy. Chenopodium ambrosioides (SE - 1.03%), Polygonum caespitosum (SE - 1.63%) and Avena fatua (SE 5.33%) had no evident allelopathy, but Artemisia annua affected the seedling height and fresh weight of radish, cucumber, wheat and maize, with the SE being 54.07%, 38.46%, 33.35% and 20.88%, respectively. Artemisia annua had a 44.70% of SE on wheat growth, and thus, had a certain value to develop and use.

  6. Effects of topsoil removal on seedling emergence and species diversity

    Energy Technology Data Exchange (ETDEWEB)

    Winkel, V.K.; Ostler, W.K.

    1994-02-01

    Approximately 800 hectares on the US Department of Energy Nevada Test Site and vicinity are contaminated with Plutonium. As part of a cleanup effort, both the vegetation and the top 5--10 cm of soil may be removed. A study was developed to determine the effects of topsoil removal on seedling emergence and plant species diversity. Trial plots were prepared by removing 5, 10, or 20 cm of topsoil, seeding a mix of nine native species, mulching with straw, and then anchoring the straw with erosion netting. Additional plots (0 topsoil removal treatment) were lightly bladed to remove existing vegetation and then treated as above. Approximately 85 mm of supplemental irrigation was applied to help initiate germination during early spring. Seedling density data of seeded and nonseeded species was collected following emergence, and species diversity was calculated with the Shannon diversity index for the nonseeded species. Densities of seeded species either were unaffected by or increased with increased depth of topsoil removal. In general, densities of nonseeded species decreased with increased depth of topsoil removal. The number of species, species diversity and evenness also decreased with increased depth of topsoil removal. Initial emergence of seeded species is apparently unaffected by topsoil removal at this site.

  7. Developmental reaction norms for water stressed seedlings of succulent cacti.

    Science.gov (United States)

    Rosas, Ulises; Zhou, Royce W; Castillo, Guillermo; Collazo-Ortega, Margarita

    2012-01-01

    Succulent cacti are remarkable plants with capabilities to withstand long periods of drought. However, their adult success is contingent on the early seedling stages, when plants are highly susceptible to the environment. To better understand their early coping strategies in a challenging environment, two developmental aspects (anatomy and morphology) in Polaskia chichipe and Echinocactus platyacanthus were studied in the context of developmental reaction norms under drought conditions. The morphology was evaluated using landmark based morphometrics and Principal Component Analysis, which gave three main trends of the variation in each species. The anatomy was quantified as number and area of xylem vessels. The quantitative relationship between morphology and anatomy in early stages of development, as a response to drought was revealed in these two species. Qualitatively, collapsible cells and collapsible parenchyma tissue were observed in seedlings of both species, more often in those subjected to water stress. These tissues were located inside the epidermis, resembling a web of collapsible-cell groups surrounding turgid cells, vascular bundles, and spanned across the pith. Occasionally the groups formed a continuum stretching from the epidermis towards the vasculature. Integrating the morphology and the anatomy in a developmental context as a response to environmental conditions provides a better understanding of the organism's dynamics, adaptation, and plasticity.

  8. Developmental reaction norms for water stressed seedlings of succulent cacti.

    Directory of Open Access Journals (Sweden)

    Ulises Rosas

    Full Text Available Succulent cacti are remarkable plants with capabilities to withstand long periods of drought. However, their adult success is contingent on the early seedling stages, when plants are highly susceptible to the environment. To better understand their early coping strategies in a challenging environment, two developmental aspects (anatomy and morphology in Polaskia chichipe and Echinocactus platyacanthus were studied in the context of developmental reaction norms under drought conditions. The morphology was evaluated using landmark based morphometrics and Principal Component Analysis, which gave three main trends of the variation in each species. The anatomy was quantified as number and area of xylem vessels. The quantitative relationship between morphology and anatomy in early stages of development, as a response to drought was revealed in these two species. Qualitatively, collapsible cells and collapsible parenchyma tissue were observed in seedlings of both species, more often in those subjected to water stress. These tissues were located inside the epidermis, resembling a web of collapsible-cell groups surrounding turgid cells, vascular bundles, and spanned across the pith. Occasionally the groups formed a continuum stretching from the epidermis towards the vasculature. Integrating the morphology and the anatomy in a developmental context as a response to environmental conditions provides a better understanding of the organism's dynamics, adaptation, and plasticity.

  9. Arsenic toxicity in soybean seedlings and their attenuation mechanisms.

    Science.gov (United States)

    Armendariz, Ana L; Talano, Melina A; Travaglia, Claudia; Reinoso, Herminda; Wevar Oller, Ana L; Agostini, Elizabeth

    2016-01-01

    Even though vast areas contaminated with arsenic (As) are under soybean (Glycine max) cultivation, little is known about the growth and intrinsic antioxidant metabolism of soybean in response to As exposure. Thus, an evaluation was carried out of plant growth, root anatomy, antioxidant system and photosynthetic pigment content under arsenate (As(V)) and arsenite (As(III)) treatment. Soybean seedling growth was significantly affected at 25 μM or higher concentrations of As(V) or As(III), and the toxic effect on root growth was associated with cell death of root tips. Microscopic analysis of cross-sections of As-treated root showed a reduction in the cortex area, dark deposits in cortex cells and broken cells in the outer layer. Similarly, in the vascular cylinder, dark deposits within xylem vessel elements and phloem cell walls were observed. In all the analyzed parameters, the deleterious effect was more evident under As(III) than As(V) treatment. Arsenic-treated soybean seedlings showed increased activity of antioxidant enzymes [total peroxidases (Px) and superoxide dismutase (SOD)] in root and shoot harvested after 2 and 5 d of treatment. However, a reduction in chlorophyll content and an increase in membrane lipids peroxidation were observed. It is suggested that root structural alterations induced by As, such as the particular pattern of dark depositions in the vascular system, could be associated with an adaptation or detoxification mechanism to prevent As translocation to the aboveground tissues.

  10. Mexican propolis flavonoids affect photosynthesis and seedling growth.

    Science.gov (United States)

    King-Díaz, Beatriz; Granados-Pineda, Jessica; Bah, Mustapha; Rivero-Cruz, J Fausto; Lotina-Hennsen, Blas

    2015-10-01

    As a continuous effort to find new natural products with potential herbicide activity, flavonoids acacetin (1), chrysin (2) and 4',7-dimethylnarangenin (3) were isolated from a propolis sample collected in the rural area of Mexico City and their effects on the photosynthesis light reactions and on the growth of Lolium perenne, Echinochloa crus-galli and Physalis ixocarpa seedlings were investigated. Acacetin (1) acted as an uncoupler by enhancing the electron transport under basal and phosphorylating conditions and the Mg(2+)-ATPase. Chrysin (2) at low concentrations behaved as an uncoupler and at concentrations up to 100 μM its behavior was as a Hill reaction inhibitor. Finally, 4',7-dimethylnarangenin (3) in a concentration-dependent manner behaved as a Hill reaction inhibitor. Flavonoids 2 and 3 inhibited the uncoupled photosystem II reaction measured from water to 2,5-dichloro-1,4-benzoquinone (DCBQ), and they did not inhibit the uncoupled partial reactions measured from water to sodium silicomolybdate (SiMo) and from diphenylcarbazide (DPC) to diclorophenol indophenol (DCPIP). These results indicated that chrysin and 4',7-dimethylnarangenin inhibited the acceptor side of PS II. The results were corroborated with fluorescence of chlorophyll a measurements. Flavonoids also showed activity on the growth of seedlings of Lolium perenne and Echinochloa crus-galli. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Physiological Responses of Cotton at Seedling Stage to Waterlogged Stress

    Directory of Open Access Journals (Sweden)

    Kai-wen Liu

    2012-12-01

    Full Text Available In Jianghan plain as well as south China, cotton at seedling stage often encounter waterlogged stress, by which normal growth of cotton plants is affected, the purpose of the study is to analyze the responses to Waterlogging stress. Therefore flooding experiments of cotton in the seedling stage was made and a series of physiological indices were observed such as Chlorophyll Relative value (RC, chlorophyll fluorescence (F0, Fm, Malondialdehyde (MDA, nomadic Proline (Pro, Dissoluble Sugar (DS, Peroxidase (POD and Superoxide Dismutase (SOD, Analytic results indicated that, after Waterlogging, chlorophyll hydrolysis rate was higher in the first 3 days, the peak value of chlorophyll fluorescence decrease occurred between the 6th to 9th day. It figured that stagnant water on the field should be drained off in 3 days after Waterlogging stress, to avoid the photosynthetic efficiency being strongly inhibited. The balance of normal physiological metabolic process in cotton leaf was broken after Waterlogging, some new negative changes occurred, as MDA content increasing and the activity of SOD decline. Some other positive changes were accompanied, as the increasing of DS and Pro content and the activity of POD, for protecting active tissues. These physiological indices appeared regularly changing characterized by fastslow- fast, which can be simulated in unary cubic regression curve model.

  12. How do riparian woody seedlings survive seasonal drought?

    Science.gov (United States)

    Stella, John C; Battles, John J

    2010-11-01

    In semi-arid regions, a major population limitation for riparian trees is seedling desiccation during the dry season that follows annual spring floods. We investigated the stress response of first-year pioneer riparian seedlings to experimental water table declines (0, 1 and 3 cm day(-1)), focusing on the three dominant cottonwood and willows (family Salicaceae) in California's San Joaquin Basin. We analyzed growth and belowground allocation response to water stress, and used logistic regression to determine if these traits had an influence on individual survival. The models indicate that high root growth (>3 mm day(-1)) and low shoot:root ratios (water-use efficiency for surviving water stress. Both S. gooddingii and sandbar willow (S. exigua) reduced leaf size from controls, whereas Fremont cottonwood (Populus fremontii) sustained a 29% reduction in specific leaf area (from 13.4 to 9.6 m(2) kg(-1)). The functional responses exhibited by Goodding's willow, the more drought-tolerant species, may play a role in its greater relative abundance in dry regions such as the San Joaquin Basin. This study highlights the potential for a shift in riparian forest composition. Under a future drier climate regime or under reduced regulated river flows, our results suggest that willow establishment will be favored over cottonwood.

  13. Cadmium interferes with maintenance of auxin homeostasis in Arabidopsis seedlings.

    Science.gov (United States)

    Hu, Yan Feng; Zhou, Guoying; Na, Xiao Fan; Yang, Lijing; Nan, Wen Bin; Liu, Xu; Zhang, Yong Qiang; Li, Jiao Long; Bi, Yu Rong

    2013-07-15

    Auxin and its homeostasis play key roles in many aspects of plant growth and development. Cadmium (Cd) is a phytotoxic heavy metal and its inhibitory effects on plant growth and development have been extensively studied. However, the underlying molecular mechanism of the effects of Cd stress on auxin homeostasis is still unclear. In the present study, we found that the root elongation, shoot weight, hypocotyl length and chlorophyll content in wild-type (WT) Arabidopsis seedlings were significantly reduced after exposure to Cd stress. However, the lateral root (LR) formation was markedly promoted by Cd stress. The level and distribution of auxin were both greatly altered in primary root tips and cotyledons of Cd-treated plants. The results also showed that after Cd treatment, the IAA content was significantly decreased, which was accompanied by increases in the activity of the IAA oxidase and alteration in the expression of several putative auxin biosynthetic and catabolic genes. Application of the auxin transport inhibitor, 1-naphthylphthalamic acid (NPA) and 1-naphthoxyacetic acid (1-NOA), reversed the effects of Cd on LR formation. Additionally, there was less promotion of LR formation by Cd treatment in aux1-7 and pin2 mutants than that in the WT. Meanwhile, Cd stress also altered the expression of PINs and AUX1 in Arabidopsis roots, implying that the auxin transport pathway is required for Cd-modulated LR development. Taken together, these findings suggest that Cd stress disturbs auxin homeostasis through affecting auxin level, distribution, metabolism, and transport in Arabidopsis seedling.

  14. Proteomic Study for Responses to Cadmium Stress in Rice Seedlings

    Institute of Scientific and Technical Information of China (English)

    GE Cai-lin; WANG Ze-gang; WAN Ding-zhen; DING Yan; WANG Yu-long; SHANG Qi; LUO Shi-shi

    2009-01-01

    A proteomic approach including two-dimensional electrophoresis and mass spectrometric (MALDI-TOF MS) analyses was used to investigate the responses to cadmium (Cd) stress in seedlings of rice (Oryza sativa L.) varieties Shanyou 63 and Aizaizhan. Cd stress significantly inhibited root and shoot growth, and affected the global proteome in rice roots and leaves, which induced or upregulated the expression of corresponding proteins in rice roots and leaves when rice seedlings were exposed to 0.1 or 1.0 mmol/L Cd. The Cd-induced proteins are involved in chelation and compartmentation of Cd, elimination of active oxygen free radicals, detoxification of toxic substances, degradation of denatured proteins or inactivated enzymes, regulation of physiologic metabolism and induction of pathogenesis-related proteins. Comparing the Cd-induced proteins between the two varieties, the β-glucosidase and pathogenesis-related protein family 10 proteins were more drastically induced by Cd stress in roots and leaves of Aizaizhan, and the UDP-glucose protein transglucosylase and translational elongation factor Tu were induced by 0.1 mmol/L Cd stress in roots of Shanyou 63. This may be one of the important mechanisms for higher tolerance to Cd stress in Shanyou 63 than in Aizaizhan.

  15. Continuous Spectrum LEDs Promote Seedling Quality Traits and Performance of Quercus ithaburensis var. macrolepis.

    Science.gov (United States)

    Smirnakou, Sonia; Ouzounis, Theoharis; Radoglou, Kalliopi M

    2017-01-01

    Regulation of the growth, development, and quality of plants by the control of light quality has attracted extensive attention worldwide. The aim of this study was to examine the effects of continuous LED spectrum for indoor plant pre-cultivation and to investigate the morphological and physiological responses of a common broadleaved tree species in Mediterranean environment, Quercus ithaburensis var. macrolepis at seedling developmental stage. Thus, the seedlings were pre-cultivated for 28 days, under five different LED light qualities: (1) Fluorescent (FL) as control light (2) L20AP67 (high in green and moderate in far-red), (3) AP673L (high in green and red), (4) G2 (highest in red and far-red), AP67 (high in blue, red, and far-red), and (5) NS1 (highest in blue and green and lowest in far-red) LEDs. Further examination was held at the nursery for 1 year, on several seedling quality traits. Indeed, AP67 and AP673L triggered higher leaf formation, while L20AP67 positively affected seedling shoot development. NS1 and AP67 LED pre-cultivated seedlings showed significantly higher root fibrosity than those of FL light. Furthermore, NS1 and AP673L LEDs induced fourfold increase on seedling root dry weight than FL light. Hence, evaluating the seedling nursery performance attributes, most of those photomorphogenetic responses previously obtained were still detectable. Even more so, LED pre-cultivated seedlings showed higher survival and faster growth indicating better adaptation even under natural light conditions, a fact further reinforced by the significantly higher Dickson's quality index acquired. In conclusion, the goal of each nursery management program is the production of high quality seedlings with those desirable traits, which in turn satisfy the specific needs for a particular reforestation site. Thus, the enhanced oak seedling quality traits formed under continuous LEDs spectrum especially of NS1 and AP673L pre-cultivation may potentially fulfill this goal.

  16. Interannual variation in rainfall, drought stress and seedling mortality may mediate monodominance in tropical flooded forests.

    Science.gov (United States)

    Lopez, Omar R; Kursar, Thomas A

    2007-11-01

    Flood tolerance is commonly regarded as the main factor explaining low diversity and monodominance in tropical swamps. In this study we examined seedling mortality in relation to seasonality, i.e., flooding versus drought, of the dominant tree species (Prioria copaifera), and three associated species (Pterocarpus officinalis, Carapa guianensis and Pentaclethra macroloba), in seasonally flooded forests (SFF) in Darien, Panama. Seedling mortality differed among species, years and seasons. Prioria seedlings experienced the lowest overall mortality, and after 3 years many more Prioria seedlings remained alive than those of any of the associated species. In general, within species, larger seedlings had greater survival. Seed size, which can vary by close to 2 orders of magnitude in Prioria, had a confounding effect with that of topography. Large-seeded Prioria seedlings experienced 1.5 times greater mortality than small-seeded seedlings, as large-seeded Prioria seedlings were more likely to be located in depressions. This finding suggests that seed size, plant size and topography are important in understanding SFF regeneration. For all species, seedling mortality was consistently greater during the dry season than during flooding. For Prioria, dry season seedling mortality was correlated with drought stress, that is, high mortality during the long El Niño dry season of 1998 and the normal dry season of 2000, but very low dry season mortality during the mild dry season of 1999. Prioria's ability to dominate in seasonally flooded forest of Central America is partly explained by its low drought-related mortality in comparison to associated species.

  17. Periodic exposure to ambient solar irradiance benefits the growth of juvenile seedlings of Hizikia fusiformis

    Institute of Scientific and Technical Information of China (English)

    SHAN Tifeng; PANG Shaojun; GAO Suqin

    2011-01-01

    In our trials,from 2007 to 2008,of mass production of seedlings of Hizikiafusiformis using synchronization techniques,problems of a “dark thalli” phenomenon and epiphytes contamination severely threatened the health of juvenile seedlings.In this investigation,we optimized conditions for improving the growth of juvenile seedlings.Seven string collectors were seeded with zygotes and a series of experiments were conducted including direct exposure to solar irradiance,co-culture with Ulva spp.and treatment with sodium hypochlorite.It was found that direct exposure to solar irradiance (maximum:1 740 μmol photons/(m2·s)) for 2 h per day could efficiently enhance the growth of young seedlings and simultaneously inhibit the growth of epiphytic algae.In this treatment,50-day old seedlings could reach an average of 0.44 cm in length and possess up to nine leaflets.However,a single treatment with 18-mmol/L sodium hypochlorite for 10 min severely harmed 15-day old seedlings.In comparison,weekly treatment with 2.2-mmol/L sodium hypochlorite for 10 min brought no apparent harm to seedlings and eliminated epiphytic algae efficiently.However,this treatment significantly increased the detachment rate of seedlings.Inoculating Ulva spp.onto the collector caused a dramatic decrease in the number of seedlings.However,the growth of the remaining seedlings appeared unhampered.All collectors except the control were daily sprayed with a high pressure water jet from the 8th day post fertilization.From the first day to 50th day,no “dark thallus” was observed on any of the seven collectors.We believe that well-timed daily exposure to solar irradiance would favor H.fusiformis in its early growing stages.

  18. Effect of Fertilization on the Morphological Development of European Hophormbeam (Ostrya carpinifolia Scop. Seedlings

    Directory of Open Access Journals (Sweden)

    Şemsettin Kulaç

    2016-10-01

    Full Text Available In this study, in order to help the mass production of seedlings, the effect of fertilization on the morphological development of hornbeam leafy European hophornbeam (Ostry carpinifolia Scop seedlings were investigated. For this, seedlings, which were obtained from the seeds coming from different European hophornbeam populations (Düzce-Yığılca, Antalya-Finike, Antalya-Akseki, Kastamonu-Şehdağ ve Adana-Saimbeyli from various parts of Turkey, were used. European hophornbeam seedlings were treated with different fertilizers, including urea, ammonium sulphate, compound fertilizer 15-15-15 and 20-20-0, and 6-9 months Osmocote release fertilizer, and effects of these fertilizers on the morphological characters were investigated. Fertilization contained the same amount of nitrogen, and was made in three different ways; (1 mixing with habitat, (2 topical application and (3 liquid application. The development of germinated European hophornbeam seeds, which were spring-sowed in the same medium were monitored during the vegetation period. At the end of vegetation period, seedlings were removed from the soil and morphological characteristics of root (seedling length, root collar diameter, root length, fresh root and stem weight of the seedlings, dried root and stem weight of the seedlings and bud number were measured. As a result, it was observed that fertilization positively affects the development of seedlings and depending on the fertilization type the seedlings of European hophornbeam populations were found to exhibit different improvements/growing. In addition, 6-9 months Osmocote release fertilizers were determined to be the best fertilizers affecting the morphological (diameter and height development of European hophornbeam populations effectively, and among the populations, Düzce and Kastamonu populations showed the best improvement/growing.

  19. Linking carbon and water relations to drought-induced mortality in Pinus flexilis seedlings.

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J; Kueppers, Lara M; Domec, Jean-Christophe; Mitton, Jeffry

    2015-07-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below -5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations.

  20. Linking carbon and water limitations to drought-induced mortality of Pinus flexilis seedlings

    Science.gov (United States)

    Reinhardt, Keith; Germino, Matthew J.; Kueppers, Lara M.; Domec, Jean-Christophe; Mitton, Jeffry

    2015-01-01

    Survival of tree seedlings at high elevations has been shown to be limited by thermal constraints on carbon balance, but it is unknown if carbon relations also limit seedling survival at lower elevations, where water relations may be more important. We measured and modeled carbon fluxes and water relations in first-year Pinus flexilis seedlings in garden plots just beyond the warm edge of their natural range, and compared these with dry-mass gain and survival across two summers. We hypothesized that mortality in these seedlings would be associated with declines in water relations, more so than with carbon-balance limitations. Rather than gradual declines in survivorship across growing seasons, we observed sharp, large-scale mortality episodes that occurred once volumetric soil-moisture content dropped below 10%. By this point, seedling water potentials had decreased below −5 MPa, seedling hydraulic conductivity had decreased by 90% and seedling hydraulic resistance had increased by >900%. Additionally, non-structural carbohydrates accumulated in aboveground tissues at the end of both summers, suggesting impairments in phloem-transport from needles to roots. This resulted in low carbohydrate concentrations in roots, which likely impaired root growth and water uptake at the time of critically low soil moisture. While photosynthesis and respiration on a leaf area basis remained high until critical hydraulic thresholds were exceeded, modeled seedling gross primary productivity declined steadily throughout the summers. At the time of mortality, modeled productivity was insufficient to support seedling biomass-gain rates, metabolism and secondary costs. Thus the large-scale mortality events that we observed near the end of each summer were most directly linked with acute, episodic declines in plant hydraulic function that were linked with important changes in whole-seedling carbon relations.

  1. The influence of seedling density in containers on morphological characteristics of European beech

    Directory of Open Access Journals (Sweden)

    Wrzesiński Piotr

    2015-09-01

    Full Text Available This study examines the influence on growth parameters, in particular the morphological features of the root system, of 1-year-old European beech seedlings cultivated in containers with two different densities. The experiment was conducted in the container nursery in Skierdy (Forest District of Jabłonna in spring 2011. After 10 months of cultivation in Hiko polyethylene containers, above- and below-ground parts of the seedlings were measured. The measurements of the root system were conducted with a scanner and the WinRHIZO software. No influence due to the seedling density on either shoot height or thickness was observed, but instead the research showed that different seedling densities affected the development of root systems. The mean root thickness and dry mass of the European beech seedlings were significantly higher at the lower density. The influence of seedling density on the development of root mass deserves special attention as it is the most important factor affecting future growth of the seedlings during cultivation. This tendency also suggests that the amount of nutrients allocated to shoot development may be higher in order to improve the efficiency of photosynthesis. At both densities, differences in biomass accumulation affected the root-toshoot ratio. In seedlings cultivated at the lower density, the increased dry root matter of the seedlings resulted in a significant increase in the root-to-shoot ratio. This may cause a potential growth advantage of these seedlings after they are planted and may thus result in a more productive cultivation.

  2. [Growth, survival and herbivory of seedlings in Brosimum alicastrum (Moraceae), a species from the Neotropical undergrowth].

    Science.gov (United States)

    Ballina-Gómez, H S; Iriarte-Vivar, S; Orellana, R; Santiago, L S

    2008-12-01

    Growth responses, survival, and herbivory, on seedlings of Brosimum alicastrum were studied in a neotropical Mexican forest. We selected 122 seedlings and divided them into three groups assigned to defoliation treatments: control or 0 (n=21), 50 (n=51) and 90% (n=50). Every 4 months during two years we measured seedling growth (in terms of relative growth rate in biomass, leaf area growth, produced leaves and height growth) and survival. In addition, we evaluated every 12 months pathogen damage and insect herbivory using a 2 mm(-2) grid. Separately, we estimated mammal herbivory in 3-month old seedlings that were selected within a plot of 500 m x 10 m (N=1095). Pathogen damage and insect herbivory were evaluated within the same plot in 113 seedlings. We found that 50% defoliated seedlings showed compensatory responses in all growth parameters. Relative growth rate and height growth also had a compensatory response in seedlings at 90% defoliation. Relative growth rate and leaf area growth gradually decreased with time although height growth seedling showed an opposite pattern. Leaves produced were not affected by time. Estimated seedling survival probability increased with defoliation to a maximum of 97%, decreasing at 24 month to 37%. Mammal herbivory was more frequent and severe than herbivory caused by pathogens and insects. In some cases, mammal herbivory produced total defoliation. Compensatory growth in leaf area growth, produced leaves and height growth seedling suggest a synergic compensatory mechanism expressed in a whole-plant growth biomass (relative growth rate). Compensation and survival results suggest trade-offs at the leaf level, such as leaf area growth and produced leaves versus chemical defenses, respectively.

  3. RESULTS ON THE EFFECT OF DIFFERENT TYPES OF ROMANIAN NATIVE PEAT BIO COMPOSITES POTS ON SEEDLING GROWTH

    Directory of Open Access Journals (Sweden)

    Florina Uleanu

    2013-07-01

    Full Text Available Seedlings production is an important link in vegetable culture because many vegetables species are grown by producing prior of seedlings. The theme work is in line with Western trends to produce seedlings by integrating new vegetables technologies, profitable, with positive effect on limiting pathogens to obtain seedlings, using biodegradable pots. Were conducted various observations and measurements on plants when they have reached the optimum phase for planting. We have determined: height of seedlings, root length, leaf number, root volume total weight, weight of the aerial and weight of roots. The obtained data was calculated and considered as average / variant.

  4. Influence of water logging time on the growth of candel seedlings

    Institute of Scientific and Technical Information of China (English)

    CHEN Luzhen; WANG Wenqing; LIN Peng

    2004-01-01

    Influence ofwaterlogging time on the growth ofKandeliacandel(L.) Druce seedlings grown for 70 d in the artificial-tidal tanks' simulated semidiumal tide under greenhouse is studied. Sand and soil act as the substrate and artificial sea-water with salinity of 15 is used in cultivation. Shorter waterlogging time (inundated for about 2 ~ 4 h) promotes thegrowth of K. candel seedlings, while longer time(inundated more than 8 h) or no waterlogging(0 h) inhibits theirgrowth. The number and length of aerating roots increase with the increase ofwaterlogging time. Under existing condi-tions, the optimalwaterlogging time for the growth of K. canoel seedlings is about 2 ~ 4 h in every tide cycle. Com-pared with other treatments, the 2 h sanded treatments obtain the highest biomass of seedlings, have the lowest massloss ofhypocotyl and broaden the photosynthetic area by increasing the area per leaf after 70-d cultivation. And the soiltreatments have the similar tendeney. However, waterlogging for 8 h in every tide cycle is critieal for normal develop-ment of seedlings. K. candel seedlings are highly tolerant to waterlogging and a proper waterlogging is beneficial to thegrowth ofK. candel seedlings.

  5. Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings

    Institute of Scientific and Technical Information of China (English)

    LIU; Wan; LI; Peijun; ZHOU; Qixing; SUN; Tieheng; TAI; Peid

    2005-01-01

    The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity,malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water (P<0.05). The experiments also revealed that a significant increase of MDA level in seedlings was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 μg · g-1 CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.

  6. Effect of electrostatic field on seed germination and seedling growth of Sorbus pohuashanesis

    Institute of Scientific and Technical Information of China (English)

    YANG Ling; SHEN Hai-long

    2011-01-01

    A study was conducted to determine the effects of electro static field (ESF) treatment on seed germination and seedling growth of Sorbus pohuashanesis. The experiments were arranged by uniform design computed by the Data Processing System (DPS), including three levels of seeds soaking time, four levels of ESF intensity and four levels of ESF treatment time, with 12 treatments. Ten seeds were used in each treatment with three replicates. Seed vigor, seed germinating ability,emergence rate of seedling, survival rate of seedling, and seedling height and diameter, as well as the change in activities of superoxide dismutase (SOD), soluble protein contents, total chlorophyll contents, soluble total sugar contents in leaves of S. pohuashanensis seedlings were measured after ESF treatments. The experiment results show that ESF treatment could improve the water absorption ability of dry seeds of S. pohuashanensis, resulting in fast germination at room temperature under light conditions. Combined treatment of ESF with cold stratification could increase seed germination percentage significantly (to 42.20%),promote seedling height growth, affect leaf SOD activity, and could raise contents of total chlorophyll, soluble protein, and total soluble sugar in leaves. Seed soaking time had a significant effect on seed relative electroconductivity, seed germination under light, SOD activity, soluble protein content and total soluble sugar content of seedling leaves. ESF intensity exerted a moderate effect on these indexes. ESF treatment time only had significant effect on total chlorophyll contents, no evident effect on other indexes.

  7. Use of aquatic macrophytes in substrate composition to produce moringa seedlings

    Directory of Open Access Journals (Sweden)

    Walda Monteiro Farias

    2016-03-01

    Full Text Available The use of aquatic macrophytes in substrate composition to produce seedlings of moringa is a sustainable alternative. Therefore, the objective of this research was to evaluate the development of moringa seedlings using substrates composed with aquatic macrophytes, and to determine concentrations of N, P and K in the seedlings. We used different combinations of weeds (M, manure (E and topsoil (TV to compose the substrates. The experiment was conducted in a 3 × 4 factorial in randomized arrangement with four replications. We evaluated plant height, crown diameter and stem, relative growth rate in height, canopy diameter and in stem, dry matter of aerial part and of roots, root length and root/shoot ratio, besides the content of N, P and K in seedlings. Moringa seedlings showed reduced growth when produced in substrates composed only with cattail. Water lettuce and substrates composed of 60% M + 30%E + 10 % TV and 70% M + 30% E, promoted greater nutrition and growth of moringa seedlings. The substrate 60M +30E +10TV composed by water hyacinth and cattail resulted in greater amount of P in moringa seedlings.

  8. Leaching of nitrogen and phosphorus during production of forest seedlings in containers.

    Science.gov (United States)

    Juntunen, Marja-Liisa; Hammar, Taina; Rikala, Risto

    2002-01-01

    Little information is available concerning the contamination risk caused by forest seedling nurseries to local surface and ground waters compared with agricultural and horticultural production. Leaching of nitrogen (N) and phosphorus (P) through peat growing medium in containers and nutrient uptake of seedlings were monitored in production of silver birch (Betula pendula Roth), Norway spruce [Picea abies (L.) Karst], and Scots pine (Pinus sylvestris L.) seedlings. About half of the applied nutrients (total amount applied = 149 to 260 kg N ha(-1) and 60 to 108 kg P ha(-1)) was premixed into the peat medium, as is usual in Finnish nursery practice, and the other half was applied to seedlings in liquid form with mobile booms. Depending on tree species, 11 to 19% of the applied N was recovered in leachates and 15 to 63% in seedlings. The undiscovered proportion varied from 19 to 71%. The amounts of leached N were 19 to 41 kg ha(-1). Only 5 to 31% of the applied P was recovered in seedlings; 16 to 64% (11 to 56 kg ha(-1)) was found in leachates. Total N and P load to the environment may increase substantially if nutrients applied in liquid fertilization outside container trays are included. Consequently, it is important to determine the sources of nutrient load in container seedling production to mitigate the risk of environment contamination.

  9. Injuries on Seedlings Caused by Potential Weed in Tropical Rain Forest Regeneration Areas

    Directory of Open Access Journals (Sweden)

    Sumardi Sumardi

    2000-07-01

    Full Text Available The experiment aimed to assess the injuries on Shorea seedlings caused by weed in artificial regeneration of tropical rain forest in Jambi. Four planting systems, strip nurse planting (using Acacia mangium, Paraserianthes falcataria and Gmelina arborea, line planting, gap planting and natural regeneration, were used. Seedling injuries were assessed based on part of seedling suppressed. Results indicated that Shorea seedling suffered from varying degrees of injuries, depending on weed species and part of the seedling suppressed. The dominance of weed and damage intensity were determined by the level of canopy opening on the planting systems. Ground cover dominated rapidly in open canopy, causing up to 55.27% injuries on the seedlings in the strips of G. arborea and P. falcataria. Whereas creepers and vines became dominant in moderate canopy opening. The injury of Shorea seedling planted under nurse tree was determined by the species and planting density of nurse tree used. Light canopy nurse tree such as P. falcataria failed to suppress ground weed, but in the contrary, A. mangium with heavy canopy still allowed creepers and vines to grow.

  10. N2-fixation and seedling growth promotion of lodgepole pine by endophytic Paenibacillus polymyxa.

    Science.gov (United States)

    Anand, Richa; Grayston, Susan; Chanway, Christopher

    2013-08-01

    We inoculated lodgepole pine (Pinus contorta var. latifolia (Dougl.) Engelm.) with Paenibacillus polymyxa P2b-2R, a diazotrophic bacterium previously isolated from internal stem tissue of a naturally regenerating pine seedling to evaluate biological nitrogen fixation and seedling growth promotion by this microorganism. Seedlings generated from pine seed inoculated with strain P2b-2R were grown for up to 13 months in a N-limited soil mix containing 0.7 mM available N labeled as Ca((15)NO3)2 to facilitate detection of N2-fixation. Strain P2b-2R developed a persistent endophytic population comprising 10(2)-10(6) cfu g(-1) plant tissue inside pine roots, stems, and needles during the experiment. At the end of the growth period, P2b-2R had reduced seedling mortality by 14 % and (15)N foliar N abundance 79 % and doubled foliar N concentration and seedling biomass compared to controls. Our results suggest that N2-fixation by P. polymyxa enhanced growth of pine seedlings and support the hypothesis that plant-associated diazotrophs capable of endophytic colonization can satisfy a significant proportion of the N required by tree seedlings growing under N-limited conditions.

  11. Use of plant residues on growth of mycorrhizal seedlings of neem (Azadirachta indica A. Juss.).

    Science.gov (United States)

    Monte Júnior, Inácio P; Maia, Leonor C; Silva, Fábio S B; Cavalcante, Uided M T

    2012-02-01

    Owing to its multiple uses in veterinary medicine, biofertilizers, pest control, etc., the commercial cultivation of neem (Azadirachta indica) has been increasing in various countries. The use of arbuscular mycorrhizal fungi (AMF) and plant by-products (composted leaves and residues of neem and sugarcane) for the propagation of seedlings can be an efficient alternative to stimulate plant growth, reducing the propagation time and conferring increased tolerance of plants to biotic and abiotic stresses. Therefore this study aimed to evaluate the effect of plant substrates and inoculation with AMF on the production of neem seedlings. Beneficial effects of the application of neem by-products to neem seedlings were observed on most of the variables analysed. However, the treatment with sugarcane cake did not improve the growth of neem seedlings. In general, the inoculation treatments using Glomus etunicatum in the composted neem substrates improved seedling growth. Neem by-products benefit the growth of seedlings of this plant under greenhouse conditions. Inoculation with G. etunicatum enhances plants growth mainly in substrates with residues of neem leaves, providing an alternative for the production of seedlings of this crop under nursery conditions, which can reduce the need for chemical fertilizers that impact the environment. Copyright © 2011 Society of Chemical Industry.

  12. GROWTH OF Jacaranda puberula Cham. SEEDLINGS IN NURSERY UNDER DIFFERENT SHADING LEVELS

    Directory of Open Access Journals (Sweden)

    Lausanne Soraya de Almeida

    2010-08-01

    Full Text Available Jacaranda puberula, known as caroba, is a species that presents potential use for the recovery of degraded areas, since it possesses fast growth and adapts well to sandy and loamy soils. It presents great aggressiveness in secondary forests and it can be used as urban tree because it produces beautiful lilac flowers. With the intention of obtaining information about potential species for use in recovery of riparian forest, were tested in the nursery of the city hall of the municipal district of Colombo, the development of seedlings of Jacaranda puberula submitted at 30, 50 and 70% of shading. There were used 40 seedlings by treatment and there were evaluated the following parameters: height (60, 90 and 120 days and diameter (90 and 120 days of all seedlings, leaf area and root and shoot dry weight of 6 seedlings per treatment. The largest averages of the analyzed variables were obtained for the 30% shading, except for root dry weight.  The seedlings exposed to full sun presented high mortality rate and was not compared to the others. The smallest averages of the analyzed variables, except for height, were observed for the shading of 70%, indicating that this treatment is not advisable for the production of seedlings of this species in nursery. The best condition for planting the seedlings appears to be in open areas with shading of 30 to 50%, since its natural occurrence is not at full exposure.

  13. Variation in Seedling Growth of Tamarindus indica (L.: A Threatening Medicinal Fruit Tree Species in Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Salim Azad

    2014-01-01

    Full Text Available Seedling growth is a precondition for conservation and sustainable use of genetic resources which depends upon understanding of breeding system, genetic inconsistency, and evolutionary forces in forest tree improvement. The aim of this study was to determine variation in seedling growth and age-age correlations of Tamarindus indica at population level in Bangladesh. The study revealed significant (P<0.05 differences of seasonal variation in seedling growth. Height and collar diameter growth showed significant (P<0.05 positive correlation with mean monthly rainfall. The study also revealed significant difference (P<0.05 of seedling growth among T. indica population. PCA illustrated rainfall, height growth, and diameter growth as the main characters in this study which defined drought as an additive character for this species. Cluster analysis of similarity showed how seedlings from 22.67°N latitude (origin separated from others. An increasing trend of age-age correlation was identified in both cases of shoot height and diameter growth. The study concluded that seed collection for either ex situ conservation or seedling production can be done from 22.67°N latitude as seedlings from that area performed better than others, and early clonal selection of T. indica can be done at the age of 9 months.

  14. Survey to Evaluate Escape of Eucalyptus spp. Seedlings from Plantations in Southeastern USA

    Directory of Open Access Journals (Sweden)

    Mac A. Callaham

    2013-01-01

    Full Text Available Interest in biomass-based energy in the southeastern Unites States has led to increased need for fast-growing tree species. Several Eucalyptus species exhibit characteristics that make them attractive in the bioenergy context. However, some of these also possess traits that suggest they could become invasive. To make a preliminary assessment of the risk of seedling establishment in the vicinity of Eucalyptus plantations, we conducted surveys at 3 sites in South Carolina and 16 sites in Florida. In South Carolina, no seedlings were detected in any sample transect. In Florida, we found seedlings within the boundaries of Eucalyptus plantations at 4 of the 16 sites surveyed. We also detected seedlings outside the boundaries of these same four plantations, but only two seedlings were detected at distances >45 m from plantation boundaries. All seedlings from Florida were either E. amplifolia, E. robusta, or E. grandis. The most predictive variable evaluated was latitude, with 27°N being the highest latitude at which seedlings established with regularity. Results of this survey indicate that, under current conditions, the spread of Eucalyptus spp. from plantations should be possible to manage with appropriate monitoring, but this should be evaluated further before Eucalyptus spp. are adopted for widespread planting.

  15. Growth and photosynthetic responses of Fraxinus mandshurica seedlings to various light environments

    Institute of Scientific and Technical Information of China (English)

    WANG Kai; ZHU Jiao-jun; YAN Qiao-ling; YU Li-zhong; SUN Yi-rong

    2011-01-01

    To determine light requirement and adaptability of Fraxinusmandshurica seedlings, the seasonal variations of photosynthetic vari-ables were measured in 3-year-old seedlings grown under four lightlevels (100%, 60%, 30%, and 15% of full sunlight) with a LI-6400 port-able photosynthesis system. The leaf chlorophyll content, special leafweight, annual height and basal diameter increment of seedlings werealso observed. The maximum and minimum values of net photosyntheticrate, maximum rate of carboxylation, and maximum rate of electrontransport of F. Mandshurica seedlings were detected with 60% and 15%of full sunlight treatments, respectively. With the decrease of light level,both light saturation point and special leaf weight significantly declined(p<0.05), but leaf chlorophyll content significantly increased (p<0.05).Annual height and basal diameter increments of seedlings grown under60% of full sunlight treatment were significantly greater than those ofseedlings under other treatments (p<0.05). It was concluded that F.mandshurica seedlings can adapt to a wide range of light environmentsfrom 15% to 100% of full sunlight by adjusting light saturation point,leaf chlorophyll content and special leaf weight. According to the maxi-mum of relative growth, 60% of full sunlight treatment is the optimumlight level for the growth of 3-year-old F. Mandshurica seedlings.

  16. Effect of CO2 Enrichment on the Growth and Nutrient Uptake of Tomato Seedlings

    Institute of Scientific and Technical Information of China (English)

    LI Juan; ZHOU Jian-Min; DUAN Zeng-Qiang; DU Chang-Wen; WANG Huo-Yan

    2007-01-01

    Exposing tomato seedlings to elevated CO2 concentrations may have potentially profound impacts on the tomato yield and quality. A growth chamber experiment was designed to estimate how different nutrient concentrations influenced the effect of elevated CO2 on the growth and nutrient uptake of tomato seedlings. Tomato (Hezuo 906) was grown in pots placed in controlled growth chambers and was subjected to ambient or elevated CO2 (360 or 720 μL L-1), and four nutrient solutions of different strengths (1/2-, 1/4-, 1/8-, and 1/16-strength Japan Yamazaki nutrient solutions) in a completely randomized design. The results indicated that some agricultural characteristics of the tomato seedlings such as the plant height, stem thickness, total dry and fresh weights of the leaves, stems and roots, the G value (G value = total plant dry weight/seedling age),and the seedling vigor index (seedling vigor index = stem thickness/(plant height × total plant dry weight) increased with the elevated CO2, and the increases were strongly dependent on the nutrient solution concentrations, being greater with higher nutrient solution concentrations. The elevated CO2 did not alter the ratio of root to shoot. The total N, P, K, and C absorbed from all the solutions except P in the 1/8- and 1/16-strength nutrient solutions increased in the elevated CO2 treatment. These results demonstrate that the nutrient demands of the tomato seedlings increased at elevated CO2 concentrations.

  17. Influences of excessive Cu on photosynthesis and growth in ectomycorrhizal Pinus sylvestris seedlings

    Institute of Scientific and Technical Information of China (English)

    HUANG Yi; TAO Shu

    2004-01-01

    Growth and photosynthesis responses were measured for Scots pine(Pinus sylvestris L. cv.) inoculated with ectomycorrhizal fungi(Suillus bovinus) under 6.5 and 25 mg/L Cu treatments to evaluate ectomycorrhizal seedlings' tolerance to heavy metal stress. Results showed that excessive Cu can significantly impair the growth and photosynthesis of pine seedlings, but such impairment is much smaller to the ectomycorrhizal seedlings. Under 25 mg/L Cu treatment, the dry weight of ectomycorrhizal seedlings is 25% lower than the control in contrary to 53% of the non-mycorrhizal seedlings, and the fresh weight of ectomycorrhizal roots was significantly higher than those of non-mycorrhizal roots, about 25% and 42% higher at 6.5 and 25 mg/L Cu treatments respectively. Furthermore, ectomycorrhizal fungi induced remarkable difference in the growth rate and pigment content of seedlings under excessive Cu stress. At 25 mg/L Cu, the contents of total chlorophyll, chlorophyll-a and chlorophyll-b were 30% higher in ectomycorrhizal plants than those in non-mycorrhizal plants. O2 evolution and electron transport of PSI and PSII were restrained by elevated Cu stress. However, no significant improvement was observed in reducing the physiological restraining in ectomycorrhizal seedlings over the non-mycorrhizal ones.

  18. Effects of seed mass on seedling success in Artocarpus heterophyllus L., a tropical tree species of north-east India

    Science.gov (United States)

    Khan, M. L.

    2004-03-01

    I examined the effects of seed mass on performance of seedlings of Artocarpus heterophyllus L. (Moraceae), a large evergreen late successional shade-tolerant tree species in three contrasting light conditions. Seed mass varied many fold from 1.5 to 14 g in A. heterophyllus. Germination and germination time showed a significant correlation with seed mass. Germination differed significantly among three light regimes (50%, 25% and 3%). Seed mass and light level significantly affected seedling survival. The seedlings that emerged from large seeds survived better than those from small seeds under all light regimes. Survival of seedlings was maximum in 25% light regime for all seed mass classes but did not differ significantly from that at 50% light regime. Survival was significantly lower in 3% light as compared to 50% and 25% light regimes. Seedling vigor (expressed in terms of seedling height, leaf area and dry weight) was also significantly affected by seed mass and light regimes. Seedlings that emerged from larger seeds and grew under 50% light regime produced the heaviest seedlings, while those resulting from smaller seeds and grown under 3% light regime produced the lightest seedlings. Resprouting capacity of seedlings after clipping was significantly affected by seed mass and light regime. Seedlings emerging from larger seeds were capable of resprouting several times successively. Resprouting was more pronounced under 50% and 25% light regimes as compared to 3% light. Success of A. heterophyllus regeneration appears to be regulated by an interactive effect of seed mass and light regime.

  19. Effects of copper on chlorophyll, proline, protein and abscisic acid level of sunflower (Helianthus annuus L.) seedlings.

    Science.gov (United States)

    Zengin, Fikriye Kirbag; Kirbag, Sevda

    2007-07-01

    The effect of copperchloride (CuCl2) on the level of chlorophyll (a+b), proline, protein and abscisic acid in sunflower (Helianthus annuus L.) seedlings were investigated Control and copper treated (0.4, 0.5 and 0.6 mM) seedlings were grown for ten days in Hoagland solution. Abscisic acid content was determined in root, shoot and leaf tissues of seedlings by HPLC. Copper stress caused significant increase of the abscisic acid contents in roots, shoots and leaves of seedlings. The increase was dependent on the copper salt concentration. Enhanced accumulation of proline in the leaves of seedlings exposed to copper was determined, as well as a decrease of chlorophyll (a+b) and total protein (p Helianthus annuus L.) seedlings. Thus, we assumed that copper levels increase above some critical points seedling growth get negative effects. This assumption is in line with previous findings.

  20. Seedling-herbivore interactions: insights into plant defence and regeneration patterns.

    Science.gov (United States)

    Barton, Kasey E; Hanley, Mick E

    2013-08-01

    Herbivores have the power to shape plant evolutionary trajectories, influence the structure and function of vegetation, devastate entire crops, or halt the spread of invasive weeds, and as a consequence, research into plant-herbivore interactions is pivotal to our understanding of plant ecology and evolution. However, the causes and consequences of seedling herbivory have received remarkably little attention, despite the fact that plants tend to be most susceptible to herbivory during establishment, and this damage can alter community composition and structure. In this Viewpoint article we review why herbivory during early plant ontogeny is important and in so doing introduce an Annals of Botany Special Issue that draws together the latest work on the topic. In a synthesis of the existing literature and a collection of new studies, we examine several linked issues. These include the development and expression of seedling defences and patterns of selection by herbivores, and how seedling selection affects plant establishment and community structure. We then examine how disruption of the seedling-herbivore interaction might affect normal patterns of plant community establishment and discuss how an understanding of patterns of seedling herbivory can aid our attempts to restore semi-natural vegetation. We finish by outlining a number of areas where more research is required. These include a need for a deeper consideration of how endogenous and exogenous factors determine investment in seedling defence, particularly for the very youngest plants, and a better understanding of the phylogenetic and biogeographical patterns of seedling defence. There is also much still be to be done on the mechanisms of seedling selection by herbivores, particularly with respect to the possible involvement of volatile cues. These inter-related issues together inform our understanding of how seedling herbivory affects plant regeneration at a time when anthropogenic change is likely to

  1. Light limitation and litter of an invasive clonal plant, Wedelia trilobata, inhibit its seedling recruitment

    Science.gov (United States)

    Qi, Shan-Shan; Dai, Zhi-Cong; Miao, Shi-Li; Zhai, De-Li; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Du, Dao-Lin

    2014-01-01

    Background and Aims Invasive clonal plants have two reproduction patterns, namely sexual and vegetative propagation. However, seedling recruitment of invasive clonal plants can decline as the invasion process proceeds. For example, although the invasive clonal Wedelia trilobata (Asteraceae) produces numerous seeds, few seedlings emerge under its dense population canopy in the field. In this study it is hypothesized that light limitation and the presence of a thick layer of its own litter may be the primary factors causing the failure of seedling recruitment for this invasive weed in the field. Methods A field survey was conducted to determine the allocation of resources to sexual reproduction and seedling recruitment in W. trilobata. Seed germination was also determined in the field. Effects of light and W. trilobata leaf extracts on seed germination and seedling growth were tested in the laboratory. Key Results Wedelia trilobata blooms profusely and produces copious viable seeds in the field. However, seedlings of W. trilobata were not detected under mother ramets and few emerged seedlings were found in the bare ground near to populations. In laboratory experiments, low light significantly inhibited seed germination. Leaf extracts also decreased seed germination and inhibited seedling growth, and significant interactions were found between low light and leaf extracts on seed germination. However, seeds were found to germinate in an invaded field after removal of the W. trilobata plant canopy. Conclusions The results indicate that lack of light and the presence of its own litter might be two major factors responsible for the low numbers of W. trilobata seedlings found in the field. New populations will establish from seeds once the limiting factors are eliminated, and seeds can be the agents of long-distance dispersal; therefore, prevention of seed production remains an important component in controlling the spread of this invasive clonal plant. PMID:24825293

  2. Light limitation and litter of an invasive clonal plant, Wedelia trilobata, inhibit its seedling recruitment.

    Science.gov (United States)

    Qi, Shan-Shan; Dai, Zhi-Cong; Miao, Shi-Li; Zhai, De-Li; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Du, Dao-Lin

    2014-08-01

    Invasive clonal plants have two reproduction patterns, namely sexual and vegetative propagation. However, seedling recruitment of invasive clonal plants can decline as the invasion process proceeds. For example, although the invasive clonal Wedelia trilobata (Asteraceae) produces numerous seeds, few seedlings emerge under its dense population canopy in the field. In this study it is hypothesized that light limitation and the presence of a thick layer of its own litter may be the primary factors causing the failure of seedling recruitment for this invasive weed in the field. A field survey was conducted to determine the allocation of resources to sexual reproduction and seedling recruitment in W. trilobata. Seed germination was also determined in the field. Effects of light and W. trilobata leaf extracts on seed germination and seedling growth were tested in the laboratory. Wedelia trilobata blooms profusely and produces copious viable seeds in the field. However, seedlings of W. trilobata were not detected under mother ramets and few emerged seedlings were found in the bare ground near to populations. In laboratory experiments, low light significantly inhibited seed germination. Leaf extracts also decreased seed germination and inhibited seedling growth, and significant interactions were found between low light and leaf extracts on seed germination. However, seeds were found to germinate in an invaded field after removal of the W. trilobata plant canopy. The results indicate that lack of light and the presence of its own litter might be two major factors responsible for the low numbers of W. trilobata seedlings found in the field. New populations will establish from seeds once the limiting factors are eliminated, and seeds can be the agents of long-distance dispersal; therefore, prevention of seed production remains an important component in controlling the spread of this invasive clonal plant. © The Author 2014. Published by Oxford University Press on behalf of

  3. Ecophysiology of seedlings of three Mediterranean pine species in contrasting light regimes.

    Science.gov (United States)

    Awada, Tala; Radoglou, Kalliopi; Fotelli, Mariangela N; Constantinidou, Helen I A

    2003-01-01

    Seasonal dynamics of net photosynthesis (Anet) in 2-year-old seedlings of Pinus brutia Ten., Pinus pinea L. and Pinus pinaster Ait. were investigated. Seedlings were grown in the field in two light regimes: sun (ambient light) and shade (25% of photosynthetically active radiation (PAR)). Repeated measures analyses over a 12-month period showed that Anet varied significantly among species and from season to season. Maximum Anet in sun-acclimated seedlings was low in winter (yet remained positive) and peaked during summer. Maximum Anet was observed in June in P. pinea (12 micromol m-2 s-1), July in P. pinaster (23 micromol m-2 s-1) and August in P. brutia (20 micromol m-2 s-1). Photosynthetic light response curves saturated at a PAR of 200-300 micromol m-2 s-1 in winter and in shade-acclimated seedlings in summer. Net photosynthesis in sun-acclimated seedlings did not saturate at PAR up to 1900 micromol m-2 s-1 in P. brutia and P. pinaster. Minimum air temperature of the preceding night was apparently one of the main factors controlling Anet during the day. In shade-acclimated seedlings, photosynthetic rates were reduced by 50% in P. brutia and P. pinaster and by 20% in P. pinea compared with those in sun-acclimated seedlings. Stomatal conductance was generally lower in shaded seedlings than in seedlings grown in the sun, except on days with a high vapor pressure deficit. Total chlorophyll concentration per unit leaf area, specific leaf area (SLA) and height significantly increased in P. pinea in response to shade, but not in P. pinaster or P. brutia. In response to shade, P. brutia showed a significant increase in total chlorophyll concentration but not SLA. Photosynthetic and growth data indicate that P. pinaster and P. brutia are more light-demanding than P. pinea.

  4. Identification of 'Ubá' mango tree zygotic and nucellar seedlings using ISSR markers

    Directory of Open Access Journals (Sweden)

    Aline Rocha

    2014-10-01

    Full Text Available Polyembryonic seeds are characterized by the development of over one embryo in the same seed, which can be zygotic and nucellar. The objective of this work was to identify the genetic origin, whether zygotic or nucellar, of seedlings of polyembryonic seeds of 'Ubá' mango tree using ISSR markers, and relating them with the vigor of the seedlings. Thus, mangos were harvested in Visconde do Rio Branco (accession 102 and Ubá (accessions 112, 138, 152 and 159, whose seeds were germinated in plastic trays filled with washed sand. Fifty days after sowing, seedlings from five seeds of each one of the accessions 102, 112, 138, 159 and from 10 seeds of the accession 152, were analyzed. These sseedlings were characterized and evaluated for plant height, stem circumference and mass of fresh aerial part and the most vigorous seedling was the one displaying at least two of these traits higher than the other seedlings from seed. Leaves were collected for genomic DNA extraction, which was amplified using seven ISSR primers previously selected based on the amplification profile and considering the number and resolution of fragments. Zygotic seedlings were found in 18 seeds, which were the most vigorous in six seeds. The results evidenced the existence of genetic variability in orchards using seedlings grown from seeds, because the farmer usually uses the most vigorous ones, assuming that this is of nucellar origin. These results also indicate that the most vigorous seedling are not always nucellar, inasmuch as of 20% of the total seeds evaluated, the zygotic seedling was the most vigorous.

  5. Adaptive Responses of Birch-Leaved Pear (Pyrus betulaefolia Seedlings to Salinity Stress

    Directory of Open Access Journals (Sweden)

    Qiang Sheng WU

    2009-06-01

    Full Text Available One-year-old birch-leaved pear (Pyrus betulaefolia Bunge seedlings were subjected to 0, 50, 100, 150, and 200 mmol/L NaCl solutions for 27 days in order to study the effects of salinity stress on photosynthesis, ion accumulation and enzymatic and non-enzymatic scavenging of reactive oxygen species in the seedlings. The research was performed in a greenhouse using potted trees. Salinity stress reduced photosynthetic rates, stomatal conductance and water use efficiency of leaves of the pear seedlings, but increased transpiration rates and leaf temperature. Hydrogen peroxide and superoxide anion radical contents increased with increasing NaCl concentrations, a phenomena also observed for malondialdehyde, suggesting that leaves of the pear seedlings suffered from oxidative injury. Superoxide dismutase (SOD and catalase (CAT activities quickly responded by increasing when the pear seedlings were subjected to salinity stress. Total protein content in leaves of the seedlings was restrained by salinity stress, whereas ascorbate content increased. Salinity stress reduced glutathione content once the birch-leaved pear seedlings were exposed to a low level (50 or 100 mmol/L of NaCl, whereas a high level (150 or 200 mmol/L NaCl of salinity stress stimulated the accumulation of glutathione. Salinity stress increased the accumulation of Na+, Cl-, K+ and Mg2+ in the seedlings, but reduced Ca2+ levels and the ratio of other ions to Na+ except K+/Na+ under 50 mmol/L NaCl conditions. This suggests that leaves of birch-leaved pear seedlings possess the capacity for salt exclusion only under 50 mmol/L NaCl conditions, and Ca2+ does not play a fundamental role as a secondary messenger under salinity stress conditions.

  6. The Diagnosis of Components Information Distribution of Wheat Seedlings Based on the Hyperspectral Imaging

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    Qiong Wu

    2012-08-01

    Full Text Available It is adopted mostly of the non-imaging spectrometer in current crop seedling monitoring, this method is greatly interfered by the soil background, makes it difficult to analyze the partial area nutritional status of the seedlings. In this study, we took advantage of merging the image with spectrum of the imaging spectrometer, to analyze the canopy, individuals, different size of leaves, characteristics of different regions of the wheat seedlings under the condition of salt stress, to diagnose the distribution of its chlorophyll composition information. We collected the imaging spectrum of 126 wheat samples in the wavelength range of 400 ~1000 nm, selected the average spectrum, exerted Correlation Analysis on the spectrum of wheat seedlings with the SPAD value, It could be seen that the biggest absolute value of the correlation coefficient was at 693 nm, which was considered as the characteristics wavelength of wheat seedlings. To establish the linear regression model using this wavelength and substituted 1the reflectance data of each point into the model, then we got the SPAD value of each point, to form the relative content distribution map of chlorophyll, whereby to diagnose the distribution of seedlings component. The results showed that: Hyper spectral imaging could reflect the reflectance differences of wheat seedlings under different salt stress treatments, through extracting the spectral reflectance curve leaves of single wheat seedlings in different parts of the different leaves and single leaf base, the midst of leaves and tip in the plant, from the results of filling map we could intuitively see the leaves’ chlorophyll distribution in different parts. It indicated that hyper spectral imaging can characterize the seedlings situation of different plants, also could characterize the characteristics of different district of leaves. The results indicated that hyper spectral imaging were suitable for the non-invasive detection of

  7. The role of nurse functional types in seedling recruitment dynamics of alternative states in rangelands

    Science.gov (United States)

    López, Dardo R.; Cavallero, Laura

    2017-02-01

    In arid ecosystems, recruitment dynamics are limited by harsh environmental conditions and greatly depend on the net outcome of the balance between facilitation and competition. This outcome can change as a consequence of degradation caused by livestock overgrazing. Also, distinct plant species may show a differential response to a common neighbour under the same environmental conditions. Therefore, ecosystem degradation could affect the net balance of plant-plant interactions, which can also depend on the functional traits of potential nurse species. The aim of this study is to assess the influence of alternative degradation states on (i) the density of seedlings of perennial species emerging in four microsite types, and on (ii) the relative interaction intensity (RII) between seedlings and potential nurses belonging to three functional types (deep- and shallow-rooted shrubs, and tussock grasses). During three years, we recorded seedling density of perennial species in four alternative degradation states in grass-shrubby steppes from northwestern Patagonia. The density of emerged seedlings of perennial species decreased sharply as degradation increased, showing non-linear responses in most microsites. Seedling density underneath deep-rooted shrubs was higher than underneath shallow-rooted shrubs and tussock grasses. Also, deep-rooted shrubs were the only functional type that recorded seedling emergence in highly degraded states. Deep-rooted shrubs had facilitative effects on the seedlings emerging and surviving underneath them, independently of ecosystem degradation. In contrast, RII between shallow-rooted shrubs and recently emerged seedlings, switched from positive effects in the less degraded states, to negative effects in the most degraded state. Tussock grasses recorded the weakest intensity of facilitative interactions with recently emerged seedlings, switching to competitive interactions as degradation increased. Our results suggest that species with key

  8. Germination requirements and seedling responses to water availability and soil type in four eucalypt species

    Science.gov (United States)

    Schütz, Wolfgang; Milberg, Per; Lamont, Byron B.

    2002-03-01

    We conducted experiments on seed germination, seedling survival and seedling growth of four Eucalyptus species to identify factors that might explain why they are restricted to the two major soil types in southwestern Australia, deep sands ( E. macrocarpa, E. tetragona) and lateritic loam ( E. loxophleba, E. wandoo). At high temperatures (28 °C), germination in darkness was lower for the two 'loam species' than for the 'sand species', while there were no differences in light or at low temperatures (10 °C). Germination commenced earlier, and was faster in the sand species than in the loam species, but was almost inhibited in all species by -1.0 MPa. E. tetragona proved the most drought-tolerant in terms of germination level and seedling survival. Seedlings of the sand species had much longer roots two weeks after germination in the absence of water stress, and the roots of more seedlings continued to elongate under moderate water stress (-1.0 MPa), than the two loam species. Roots were longer in all species, except E. macrocarpa, at -0.5 MPa than at -0.1 MPa, despite seedlings having a smaller mass and hypocotyl length. As water availability declined, there was a tendency for the sand species to survive longer on sand than on loam while soil type had no effect on the loam species. Pattern and duration of seedling survival of the loam species was similar to that of the sand species despite their smaller seeds. We conclude that seedlings from the large-seeded sand species are able to penetrate the soil profile faster and deeper, but that they are not less prone to drying soils than seedlings from the small-seeded loam species. Instead, seed size and germination speed are important prerequisites to cope successfully with unstable soil surfaces and to exploit the rapidly descending water in deep sands.

  9. Seedling Regeneration in the Alpine Treeline Ecotone: Comparison of Wood Microsites and Adjacent Soil Substrates

    Directory of Open Access Journals (Sweden)

    Adelaide Chapman Johnson

    2016-11-01

    Full Text Available Although climate warming is generally expected to facilitate upward advance of forests, conifer seedling regeneration and survival may be hindered by low substrate moisture, high radiation, and both low and high snow accumulation. To better understand substrate-related factors promoting regeneration in the alpine treeline ecotone, this study compared 2 substrates supporting conifer seedlings: rotten downed wood and adjacent soil. Study locations, each with 3 levels of incoming radiation, were randomly selected at forest line–alpine meadow borders in Pacific Northwest wilderness areas extending along an east–west precipitation gradient. Associations among substrate type, seedling density, radiation, site moisture, site temperature, plant water potential, and plant stomatal conductance were assessed. Wood microsites, flush with the ground and supporting Abies spp conifer seedlings, extended up to 20 m into alpine meadows from the forest line. Although wood microsites thawed later in the spring and froze earlier in the fall, they had warmer summer temperatures, greater volumetric water content, and more growing degree hours, and seedlings growing on wood had higher water potentials than seedlings growing on adjacent soil. At drier eastern sites, there was a positive relationship between seedling density and volumetric water content. Further, there was a positive relationship between seedling stomatal conductance and volumetric water content. Our study indicates that in the Pacific Northwest. and likely elsewhere, seedlings benefit from wood microsites, which provide greater water content. Given predictions of increased summer drought in some locations globally, wood microsites at forest line–alpine meadows and forest line–grasslands borders may become increasingly important for successful conifer regeneration.

  10. Spatial variation in tree seedling density after the site preparation for planting in a cleared coniferous plantation in Hokkaido, northern Japan

    OpenAIRE

    Shin, ChangSeob; Shibuya, Masato

    2007-01-01

    To study spatial variation in natural tree seedling density and the relationship between variation in seedling density and seed dispersal mode at a cleared site, we surveyed natural tree seedlings after the site preparation for planting in a coniferous plantation cleared by a typhoon disturbance in 2004. The site was located near Sikotsuko Lake, Hokkaido, northern Japan. Twenty-five tree seedling species were found and the mean seedling density was 9.8 seedlings/m2. Seedlings of non-animal-di...

  11. Nutrient utilization in some tropical forest tree seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Lalman, M.A.

    1985-01-01

    The concentration of N, P, K, Ca and Na in seedlings of Dalbergia sissoo, Tamarindus indica, Diospyros melanoxylon, Terminalia arjuna and Tectona grandis was evaluated in field plantings in Uttar Pradesh, from the age of 1 to 12 months (April 1978 to March 1979). In all species, concentration of Na in leaves was higher than that of K, Ca and P (highest in D. melanoxylon) and was higher in leaves than in roots and stems. Concentration was found to increase with age of leaves up to 8-9 months (at the time of yellowing), after which N, P and K contents decreased rapidly. N, P and K content of stems and roots showed steady increase with age, but Ca and Na, after showing increases up to 8-10 months showed a slight reduction in the 11th and 12th months. 51 references.

  12. Tillers induction in Bactris gasipaes var. gasipaes seedlings

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    Ernani Augusto Ochekoski Mossanek

    2014-04-01

    Full Text Available Bactris gasipaes produces heart-of-palm. Peach palm is a perennial crop that has a tillering capacity, being an alternative to illegal extraction. There is a lack of studies about vegetative propagation technics for this species. The present study aimed to analyze different tillering induction methods in Bactris gasipaes var. gasipaes seedlings in four different seasons. The treatments were: 1 stem bending; 2 stem bending and application of 150 mg kg-1 of benzylaminopurine; 3 stem bending and application of 150 mg kg-1 of gibberellic acid and; 4 stem girdling. The experimental design was random with 4 replicates of 20 plants per treatment. Anatomical analyses were conducted at the stem, and the tillering and mortality of the treated plants were evaluated. It was possible to identify the stem tissues and the meristematic apex site by anatomical analysis. The stem bending treatments were inefficient; but girdling presented potential as tillers inducer.

  13. Measurement of seedling growth rate by machine vision

    Science.gov (United States)

    Howarth, M. Scott; Stanwood, Phillip C.

    1993-05-01

    Seed vigor and germination tests have traditionally been used to determine deterioration of seed samples. Vigor tests describe the seed potential to emerge and produce a mature crop under certain field conditions and one measure is seedling growth rate. A machine vision system was developed to measure root growth rate over the entire germination period. The machine vision measurement technique was compared to the manual growth rate technique. The vision system provided similar growth rate measurements as compared to the manual growth rate technique. The average error between the system and a manual measurement was -0.13 for the lettuce test and -0.07 for the sorghum test. This technique also provided an accurate representation of the growth rate as well as percent germination.

  14. Correlations between polyamine ratios and growth patterns in seedling roots

    Science.gov (United States)

    Shen, H. J.; Galston, A. W.

    1985-01-01

    The levels of putrescine, cadaverine, spermidine and spermine were determined in seedling roots of pea, tomato, millet and corn, as well as in corn coleoptiles and pea internodes. In all roots, putrescine content increased as elongation progressed, and the putrescine/spermine ratio closely paralleled the sigmoid growth curve up until the time of lateral root initiation. Spermidine and spermine were most abundant near the apices and declined progressively with increasing age of the cells. In the zone of differentiation of root hairs in pea roots, putrescine rose progressively with increasing age, while cadaverine declined. In both pea internodes and corn coleoptiles, the putrescine/spermidine ratio rises with increasing age and elongation. Thus, a block in the conversion of the diamine putrescine to the triamine spermidine may be an important step in the change from cell division to cell elongation.

  15. Seedling test and genetic analysis of white poplar hybrid clones

    Institute of Scientific and Technical Information of China (English)

    LI Bo; JIANG Xi-bing; ZHANG You-hui; ZHANG Zhi-yi; LI Shan-wen; AN Xin-min

    2008-01-01

    Cross breeding strategies are very efficient for gaining new and superior genotypes. Ninety-eight new white poplar hybrid clones produced from 12 cross combinations within the Section Leuce Duby were studied using genetic analysis and seedling tests. We exploited the wide variation that exists in this population and found that the differences among diameter at breast height (DBH), root collar diameter (RCD) and height (H) were statistically extremely significant. The repeatability of clones of these measured traits ranged from 0.947-0.967, which indicated that these Waits were strongly controlled by genetic factors. Based on multiple comparisons, a total of 25 clones showed better performance in growth than the conlrol cultivar. These 25 clones were from six different cross combinations, which can guarantee a larger genetic background for future new clone promotion projects. This study provides a simple overview on these clones and can guide us to carry out subsequent selection plans.

  16. Development of an automatic visual grading system for grafting seedlings

    Directory of Open Access Journals (Sweden)

    Subo Tian

    2017-01-01

    Full Text Available In this study, a visual grading system of vegetable grafting machine was developed. The study described key technology of visual grading system of vegetable grafting machine. First, the contrasting experiment was conducted between acquired images under blue background light and natural light conditions, with the blue background light chosen as lighting source. The Visual C++ platform with open-source computer vision library (Open CV was used for the image processing. Subsequently, maximum frequency of total number of 0-valued pixels was predicted and used to extract the measurements of scion and rootstock stem diameters. Finally, the developed integrated visual grading system was experimented with 100 scions and rootstock seedlings. The results showed that success rate of grading reached up to 98%. This shows that selection and grading of scion and rootstock could be fully automated with this developed visual grading system. Hence, this technology would be greatly helpful for improving the grading accuracy and efficiency.

  17. Vegetation management for reducing mortality of ponderosa pine seedlings from Thomomys spp

    Science.gov (United States)

    Barnes, V.G.; Anthony, M.; ,

    1995-01-01

    The effects of vegetation management on Mazama pocket gopher activity and damage to ponderosa pine seedlings were studied using atrazine herbicide to alter the habitat. Atrazine treatments were applied to a large treatment unit and observed effects were compared to an untreated control unit. The greatly reduced forb and grass cover on the treated unit was associated with a corresponding decrease in pocket gopher activity. Times until seedlings first incurred gopher damage and overall survival of two cohorts of seedlings were greatly increased on the treated unit.

  18. Effects of different substrates on basil seedlings quality (Ocimum basilicum L.

    Directory of Open Access Journals (Sweden)

    Jelačić Slavica

    2005-01-01

    Full Text Available In this study five different substrates were used, such as: compost; mixture of compost, Lumbrikus H and garden soil; mixture of compost and Lumbrikus H; mixture of compost, Lumbrikus H and peat Galicina and Seedling Klassman substrate. Basil seedling was produced in containers according to "speeding" system. The studies have shown that the best quality of basil seedling of varieties Genovese and Lattuga is achieved when the mixture of substrates Compost, Lumbrikus H and Galicina peat are applied in the volume proportion of 50% : 30% : 20%.

  19. Response of seedlings growth of Pinus sylvestriformis to atmospheric CO2 enrichment in Changbai Mountain

    Institute of Scientific and Technical Information of China (English)

    Han S hijie; Wang Chen rui; Zhang Junhui; Zou Chunjing; Zhou Yumei; Wang Xiaochun

    1999-01-01

    The biomass and ratio of root-shoot of Pinus sylvestriformis seedlings at CO2 concentration of 700 μL· L-1 and 500 μL· L-1 were measured using open-top chambers (OTCs) in Changbai Mountain during Jun.to Oct. in 1999. The results showed that doubling CO2 concentration was benefit to seedling growth of the species (500 μL· L-1 was better than 700 μL-L-1 ) and the biomass production was increased in both aboveground and underground parts of seedlings. Carbon transformation to roots was evident as rising of CO2 concentration.

  20. [Effects of seed coating formulation on seedling characters of Atractylodes macrocephala].

    Science.gov (United States)

    Yu, X; Sheng, S; Wang, Z; Xu, J; Yao, J; Shao, M

    2001-09-01

    The effects of seed coating formulation (SCF) of Atractylodes macrocephala Koidz. on seedling in two experimental plots located in Hangzhou and Jiande were studied, and desinged with L9(3(4)) orthogonal comparison. The results showed that the SCF with paclobutrazol (pp333) had a significant effect on the rate of germination at Hangzhou plot, all factors had no significant effects on length of seedlings in both plots, and both atonik (sodium O-nitrophenolate) and PP333 on the fresh or dry seedling weight had significant effects.

  1. Effects of Different Quantities of Tea-leaf Wormcast Substrate on the Growth of Tomato Seedling

    OpenAIRE

    Yang, Wei; Hu, Feng; Wang, Dong-sheng; LIU Man-qiang; Li, Hui-Xin; HUANG Zhong-yang; Chang, Yi-Jun; JIAO Jia-guo

    2015-01-01

    The tomato seedling experiment was conducted to investigate the effect of substrate on the tomato seedling growth from five proportions of tea-leaf wormcast to peat, perlite and vermiculite, namely treatment I(1:5:2:2), treatment Ⅱ(2:4:2:2), treatment Ⅲ(3:3:2:2), treatment Ⅳ(4:2:2:2), treatment Ⅴ(6:0:2:2), respectively. The botany properties and characters of tomato seedling were observed to discuss the application effect of tea-leaf wormcast substrate. The results showed that in all treatmen...

  2. Responses of fractal dimensions of Picea koraiensis seedlings to different light environments

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The changes of fractal dimension of Picea koraiensis seedlings under different light intensities in natural secondary forests was studied. The results showed that with the change of light environment, crown characters of Picea koraiensis seedlings exhibited a greater plastic in lateral number, lateral increment, lateral dry weight, and specific leaf area. The range of calculated fractal dimensions of seedling crowns was confined between 2.5728 and 2.1036, but maximum of fractal dimension achieved in term moderate shading and in extreme low light conditions fractal dimension was least.

  3. Effect of La3+ on Activities of Antioxidant Enzymes in Wheat Seedlings under Mercury Stress

    Institute of Scientific and Technical Information of China (English)

    庞欣; 王东红; 彭安; 张福锁; 邢晓燕; 李春俭

    2002-01-01

    The effects of La(NO3)3 on the growth,activities of SOD,CAT and MDA content in shoots and roots of wheat seedlings under mercury stress were evaluated by the nutrient solution culture experiment. The results suggest that there is positive effect of La(NO3)3 on enhancing the activities of SOD,CAT,decrease of MDA content in shoots and roots of wheat seedlings during 0~5 d. But La(NO3)3 evens and cooperates with mercury when plants are too long under mercury stress. Mercury inhibits the growth of wheat seedlings more grievously.

  4. Interaction between hydrotropism and gravitropism in seedling roots

    Science.gov (United States)

    Kobayashi, A.; Takahashi, A.; Yamazaki, Y.; Kakimoto, Y.; Higashitani, A.; Fujii, N.; Takahashi, H.

    Roots display positive hydrotropism in response to a moisture gradient, which could play a role in avoiding drought stress. Because roots also respond to other stimuli such as gravity, touch and light and exhibit gravitropism, thigmotropism and phototropism, respectively, their growth orientation is determined by interaction among those tropisms. We have demonstrated the interaction between hydrotropism and gravitropism. For example, 1) agravitropic roots of pea mutant strongly respond to a moisture gradient and show positive hydrotropism by overcoming gravitropism, 2) in wild type pea roots hydrotropism is weak but pronounced when rotated on clinostat, 3) cucumber roots are positively gravitropic on the ground but become hydrotropic in microgravity, and 4) maize roots change their growth direction depending on the intensities of both gravistimulation and hydrostimulation. Here we found that Arabidopsis roots could display strong hydrotropism by overcoming gravitropism. It was discovered that amyloplasts in the columella cells are rapidly degraded upon exposure to a moisture gradient. Thus, degradation of amyloplasts could reduce the responsiveness to gravity, which could pronounce the hydrotropic response. In hydrotropically stimulated roots of pea seedlings, however, we could not observe a rapid degradation of amyloplasts in the columella cells. These results suggest that mechanism underlying the interaction between hydrotropism and gravitropism differs among plant species. To further study the molecular mechanism of hydrotropism and its interaction with gravitropism, we isolated unique mutants of Arabidopsis of which roots showed either ahydrotropism, reduced hydrotropism or negative hydrotropic response and examined their gravitropism, phototropism, waving response, amyloplast degradation and elongation growth. Based on the characterization of hydrotropic mutants, we will attempt to compare the mechanisms of the two tropisms and to clarify their cross talk for

  5. Tolerance of wheat varieties seedlings by glyphosate accelerated degradation

    Directory of Open Access Journals (Sweden)

    Jerković Zoran

    2014-01-01

    Full Text Available Lengths of seedlings aboveground parts of nine wheat varieties grown in greenhouse were reduced by 4-20%. They were tested during April at around 20oC after twice daily treatments with glyphosate based herbicide (0.5 ml in 1l water solution, 0.5 dl on 0.5 m2. When results of permanent artificially and daily lighted trials were compared, four groups of varieties were recognized same as was when near isogenic lines containing different leaf rust resistance genes (Lr NILs were focused in winter. Growth of variety Pobeda decreased more when seedlings were not permanent lighted which confirmed the common herbicide effect. Tolerance of other varieties was again explained by enzymatic degradation of glyphosate and chlorophyll inhibition by consequential phosphorus acids. Varieties Simonida, Tavita and Rapsodia were similar by reaction to glyphosate as Lr 1 and Lr 21 NILs. NS 40S contained Lr 3a with increased hydrolytic stability compared to Lr 24 but able to cleave external single phosphorus for the difference of Lr 19 or Lr 29. Their final effect was similar to previous stated of Lr 15 NIL during the winter. Varieties Gora and Metka had gene Lr 19, Enigma Lr 29 while Ilina Lr 24. Focusing herbicide residua transfer in seed probability, accounting optimal time for recovering ability of chlorophyll and temporary higher temperatures necessary for Lr genes even parasite free activity the varieties Gora, Metka and Enigma appeared to be possible solution for glyphosate apply near wheat heading in semiarid regions.

  6. Amelioration of arsenic toxicity by phosphate salts in mungbean seedlings.

    Science.gov (United States)

    Swarnakar, Arpita; Mukherji, Subhendu

    2005-07-01

    Sodium arsenate (Na2HAsO4.7H2O) is a potent inhibitor of mungbean seed germination and seedling growth. Germination is totally stopped at or above 50 microM Na2HAsO4.7H2O. Inhibition of seedling elongation started at a lower concentration of 5 microM As(V) and was drastically reduced at 20 microM As(V). Nutrients like salts of macroelements viz., NaH2PO4.2H2O, KH2PO4, K2SO4, MgSO4.7H2O, CaCl2.2H2O, (NH4)2SO4 NH4NO3 solutions at a concentration of 10mM and microelements viz., ZnSO4, CuSO4.5H2O, Na2MoO4.2H2O, MnCl2.4H2O, CoCl2.6H2O, FeSO4.7H2O solutions at a concentration of 1mM could help to ameliorate the toxic effects of As(V) to different degrees. Amelioration of As(V) toxicity was possible only when the mungbean seeds were pretreated with the above mentioned nutrients for 24 hr and then transferred to sodium arsenate. Simultaneous treatment of nutrients with As(V) or using nutrient solutions following As(V) treatment were of no help to reverse the toxic effects of sodium arsenate.

  7. Carbohydrate accumulation in the needles of Siberian stone pine seedlings

    Directory of Open Access Journals (Sweden)

    A. Panov

    2013-12-01

    Full Text Available The aim of the research presented is to study effects extracted from biologically active peat substances on carbohydrate accumulationprocesses. The study was carried out on 5-year-old Siberian stone pine seedlings grown in the nursery forest in the southern part of the Tomsk region. These seedlings were treated with a peat preparation, which was created in Tomsk. Four groups of experimental plants were organized on the analog principle. Each group consisted of 30 seedlings of average size and half of these seedlings were control. At the beginning of the vegetative season, a single treatment was applied to experimental plants with water solution peat preparation. The first group of plants was treated with a 0.1% solution; the dose was calculated by dry substance. For the second group, the dose was increased by 25%. For the third and fourth groups, the dose was decreased by 25% relative to the first group. Control plants were sprayed with water. Accumulation of carbohydrates and pigments as well as growth values in the 2-year- old needles were studied by standard methods. Glucose levels in the experimental plants existed within the limits 117-120%. On the whole, simple sugar quantity did not differs between experimental variants.Glucose synthesis was accompanied by changes in quantitative values of fructose. This, connected with glucose being a more stable compound, and compulsory conversion from glucose to labile form fructose was necessary. The amount of fructose in the experimental seedlings had a very wide range. This process was accompanied by shoot elongationin Siberian stone pine in the first year after treatment, with the fructose amount of 14% exceeding control values in the first and fourth group. Shoot growth was accompanied by increased fructose amount to 20% relative to control. A similar situation was observed afterwinter with respect to buds. Experimental plants dominated by number of buds

  8. Protocols for sagebrush seed processing and seedling production at the Lucky Peak Nursery

    Science.gov (United States)

    Clark D. Fleege

    2010-01-01

    This paper presents the production protocols currently practiced at the USDA Forest Service Lucky Peak Nursery (Boise, ID) for seed processing and bareroot and container seedling production for three subspecies of big sagebrush (Artemisia tridentata).

  9. Effects of 24-Epibrassinolide on Antioxidant System in Cucumber Seedling Roots Under Hypoxia Stress

    Institute of Scientific and Technical Information of China (English)

    KANG Yun-yan; GUO Shi-rong; LI Juan; DUAN Jiu-ju

    2007-01-01

    This article aims to study the effects of exogenous 24-epibrassinolide (EBR) on the changes in ROS, activities of antioxidative enzymes and antioxidants in cucumber (Cucumis sativus L.) seedling roots under hypoxia stress. Seedlings of a hypoxianormoxic or hypoxic nutrient solutions that were added or not added with 10-3 mg L-1 EBR. Under hypoxia stress, the ROS levels and the lipid peroxidation were significantly increased in the roots upon exposure to hypoxia stress, which were inhibited by EBR application. The EBR treatment significantly increased the seedlings growth and SOD, APX, GR activities, and contents of AsA and GSH under hypoxia stress. From the results obtained in this study, it can be concluded that oxidative damage on seedling roots by hypoxia stress can be considerably alleviated and the tolerance of plants was elevated.

  10. The mycorrhizal fungus Tricholoma matsutake stimulates Pinus densiflora seedling growth in vitro.

    Science.gov (United States)

    Guerin-Laguette, Alexis; Shindo, Katsumi; Matsushita, Norihisa; Suzuki, Kazuo; Lapeyrie, Frédéric

    2004-12-01

    While it has been suggested that Matsutake mycorrhizae might not be functional and that Matsutake may behave as a saprobic fungus in soil or even have some pathogenic activity on seedlings, we investigated the consequences of Matsutake inoculation on Pinus densiflora growth. Seventy-five days after inoculation, hyphae were anchored on short roots and well-developed Hartig net palmettis were observed. Compared to both control treatments--seedlings treated with distilled water and seedlings treated with autoclaved mycelium--inoculation significantly stimulated seedling total dry weight by 70.9% and 98.0%, respectively. These findings attest that some type of symbiotic relationship must be functional and favour host growth, ruling out claims of pathogenicity under the sterile conditions used here.

  11. Interaction between a dark septate endophytic isolate from Dendrobium sp. and roots of D. nobile seedlings.

    Science.gov (United States)

    Hou, Xiao-Qiang; Guo, Shun-Xing

    2009-04-01

    Interactions between an isolate of dark septate endophytes (DSE) and roots of Dendrobium nobile Lindl. seedlings are reported in this paper. The isolate was obtained from orchid mycorrhizas on Dendrobium sp. in subtropical forest. The fungus formed typical orchid mycorrhiza in aseptic co-culture with D. nobile seedlings on modified Murashige-Skoog (MMS) medium. Anatomic observations of the infected roots showed that the DSE hyphae invaded the velamen layer, passed through passage cells in exodermis, entered the cortex cells, and then formed fungal pelotons of orchid mycorrhiza. D. nobile seedlings' plant height, stem diameter, new roots number and biomass were greatly enhanced by inoculating the fungus to seedlings. The fungus was identified as Leptodontidium by sequencing the polymerase chain reaction-amplified rDNA ITS1-5.8S-ITS2 (internal transcribed spacer (ITS)) regions and comparison with similar taxa.

  12. Association mapping of germinability and seedling vigor in sorghum under controlled low-temperature conditions

    National Research Council Canada - National Science Library

    Burrell, A. Millie; Upadhyaya, Hari D; Klein, Robert R; Wang, Yi-Hong; Prasad, P.V. Vara; Klein, Patricia E; Sastry, Dintyala V.S.S.R; Morris, Geoffrey P; Dwivedi, Sangam L

    2016-01-01

    ..., sorghum’s sensitivity to low soil temperatures adversely impacts seed germination. In this study, we evaluated the 242 accessions of the ICRISAT sorghum mini core collection for seed germination and seedling vigor at 12...

  13. Morphology and anatomy of the seedling and the tirodendro of Calophyllum brasiliense Cambess. (Clusiaceae

    Directory of Open Access Journals (Sweden)

    Valquíria Aparecida Mendes de Jesus

    2014-10-01

    Full Text Available Calophyllum brasiliense Cambess. is a tree species that is presented as an alternative to replace endangered species of hardwood. The morphology and anatomy of the seedling of this species is the object of the present study. Seedlings at different stages of development were obtained in greenhouse and analyzed fresh and fixed in FAA (Formalin-Acetic-Alcohol 50. The anatomical analysis was done by the freehand and microtome sections, according to standard techniques in plant anatomy. The seedling and/or tirodendro is cryptocotylar and hypogeal, has cataphylls, and presents eophylls and metaphylls simple with venation pinnate craspedodromous simple. The root is polyarch, the hypocotyl is very short, the cotyledons have an oily and starchy reserve, the epicotyl has stem structure, and eophylls and metaphylls are dorsiventral. The seedling may be classified in the Horsfieldia type/subtype.

  14. DRENCH OF SEEDLINGS AS ECOLOGICAL AND ECONOMIC FEASIBLE METHOD OF TOBACCO PROTECTION AGAINST WIREWORMS

    Directory of Open Access Journals (Sweden)

    Renata Bažok

    2012-06-01

    Full Text Available The cultivation of seedlings in hydroponics, the ban of methyl bromide and the discovery of highly systemic insecticides from the neonicotinoid group have opened up new possibilities in tobacco protection against pests. It was supposed that tobacco seedlings drenched in the solution of tiamethoxam would result in efficient protection of transplanted plants against wireworms. The efficacy of tiamethoxam applied as drench or irrigation of seedlings or transplanted plants was compared with the efficacy obtained by standard granular insecticide (tefluthrin in the two-year research in the condition of high infestation by Agriotes ustulatus Schall. larvae. The results show that drench of seedlings is easy and very practical method having satisfactory efficacy against wireworms. Even though statistical analysis doesn’t support this, it was obvious that a certain favorable impact of tiametoxam on the vigour of the plant (exuberant and faster growth and healthier appearance in general exists.

  15. Seedling stage strategies as a means of habitat specialization in herbaceous plants

    DEFF Research Database (Denmark)

    ten Brink, Dirk-Jan; Bruun, Hans Henrik

    2011-01-01

    The regeneration niche has been little investigated in studies of community assembly and plant distribution. We examined adaptive associations between seedling traits and habitat specialization. Two habitat contrasts were investigated across several evolutionary lineages of angiosperms: species...

  16. The role of vanillin and p-coumaric acid in the growth of Scotch pine seedlings

    Directory of Open Access Journals (Sweden)

    M. Michniewicz

    2015-01-01

    Full Text Available It was stated that vanillin and p-coumaric acid used at concentrations 10-8-10-5M stimulated the growth of pine seedlings. Most effective were these substances used at concentration 10-7M. Both phenolic compounds stimulated the elongation, fresh and dry weight in very young seedlings (up to 3-4 weeks and increased the fresh and dry weight only in older ones (7 weeks. The stimulation of growth processes in pine seedlings treated with vanillin and p-coumaric acid coincided with the increase of auxins in roots and with the decrease of free gibberellins in these plant organs. Neither vanillin nor p-coumaric acid influenced the level of ABA-like inhibitor both in the shoots and roots of pine seedlings.

  17. BIO-ACCUMULATION AND RELEASE OF MERCURY IN VIGNA MUNGO (L. HEPPER SEEDLINGS

    Directory of Open Access Journals (Sweden)

    Hussain. K

    2010-09-01

    Full Text Available Effect of mercury on the seedling of Vigna mungo seedlings was studied by culturing the seedlings in Hoagland medium artificially contaminated with 5 and 10mM Mercuric Chloride. Histochemical localization of the mercury in shoot and root tissues was done by staining with dithizone and quantitative analyses of mercury content accumulated in root, stem and leaf tissues were done using mercury analyser. Localization of mercury was observed as coloured masses in the cells of root and stem. Stem tissues of seedlings showed anatomical modification in the epidermal cells as trichomes. Patterns of bioaccumulation of mercury was root> stem> leaves revealing feeble translocation to the shoot system. A comparison of residual mercury content retained in the growth medium after sample harvesting and quantity accumulated in the plant body reveals that some quantity of mercury is lost presumably through the trichomes developed on the stem and/ or through stomata of the leaves.

  18. Community-wide spatial and temporal discordances of seed-seedling shadows in a tropical rainforest

    National Research Council Canada - National Science Library

    Rother, Débora Cristina; Pizo, Marco Aurélio; Siqueira, Tadeu; Rodrigues, Ricardo Ribeiro; Jordano, Pedro

    2015-01-01

    ... (bamboo and non-bamboo stands) from the Brazilian Atlantic Forest. Spatial distribution patterns, spatial concordance between seed rain and seedling recruitment between subsequent years in two fruiting seasons...

  19. Defoliation by pastoralists affects savanna tree seedling dynamics by limiting the facilitative role of canopy cover.

    Science.gov (United States)

    Bufford, Jennifer L; Gaoue, Orou G

    2015-07-01

    Recurrent tree defoliation by pastoralists, akin to herbivory, can negatively affect plant reproduction and population dynamics. However, our understanding of the indirect role of defoliation in seedling recruitment and tree-grass dynamics in tropical savanna is limited. In West African savanna, Fulani pastoralists frequently defoliate several fodder tree species to feed livestock in the dry season. We investigated the direct and indirect effects of recurrent defoliation of African mahogany (Khaya senegalensis) by Fulani people on seedling (forest systems in West Africa, it has the potential to affect tree-grass coexistence. Incorporating the influence of large tree defoliation into existing models of savanna dynamics can further our understanding of tree-grass coexistence and improve management. A rotating harvest system, which allows seedlings to recruit episodically, or a patchwork harvest, which maintains some nursery trees in the mosaic, could help sustain seedling recruitment and minimize the indirect effects of harvest.

  20. Effects of soilless and soil-based nursery media on seedling ...

    African Journals Online (AJOL)

    Effects of soilless and soil-based nursery media on seedling emergence, growth and response to water stress of African breadfruit (Treculia africana Decne) ... African Journal of Biotechnology. Journal Home · ABOUT · Advanced Search ...

  1. Agroforestry wastes used for germination and development of sweet angelim seedlings

    Directory of Open Access Journals (Sweden)

    João Ricardo Avelino Leão

    2013-03-01

    Full Text Available This paper aimed to define the ideal type of agroforestry substrate and the adequate depth of sweet angelim sowing, providing information on the development of seedlings, as well as on low-cost substrates which are easy to be obtained. An experiment in a greenhouse was carried out, in a completely randomized design with treatments distributed in a factorial scheme (5x3, with the factors agroforestry substrates and depths being replicated seven times with a seed in each container. The following parameters were analyzed: germination percentage, germination speed index, total dry weight, number of leaves, seedlings height and coll diameter, and Dickson’s seedling quality index. The results showed that the most suitable substrate for germination and development of this native species was that containing Brazil nut shell, peanut hull, or açai seed, and the ideal depth for sowing and managing seedlings was on the surface.

  2. Produce of seedlings of cedar in function of types of container and fertilization sources

    Directory of Open Access Journals (Sweden)

    Osmar Henrique de Castro Pias

    2015-06-01

    Full Text Available The aim of this study was to evaluate the production of cedar seedlings according to the size of containers and nutrient sources. It was tested three types of containers (Root trainers, plastic bag and plastic vase, three sources of fertilization (Conventional, Kimcoat® and Osmocote® in seven evaluations. The cedar seedlings in root trainers, fertilized with source Osmocote® presented the greatest increments in height and stem diameter when compared to another sources of fertilization. The plastic bag and plastic vase containers promoted similar seedlings height growth. However the seedlings grown in plastic vase presented greatest growth in stem diameter when compared with the ones in plastic bag.

  3. Grafting Seedling Techniques of Chestnut%板栗嫁接育苗技术

    Institute of Scientific and Technical Information of China (English)

    李国举

    2014-01-01

    Grafting seedling techniques of chestnut were summarized from rootstock breeding,scion collecting and processing,grafting etc.,so as to provide reference for seedling of chestnut growers.%从砧木培育、接穗采集及处理、嫁接等方面总结了板栗嫁接育苗技术,以期为板栗种植者育苗提供参考。

  4. Root system architecture: The invisible trait in container longleaf pine seedlings

    Science.gov (United States)

    Shi-Jean Susana Sung; R. Kasten Dumroese

    2013-01-01

    Longleaf pine (Pinus palustris Mill.) seedlings cultured in four cavity volumes (60 to 336 ml [3.7 to 20.5 cubic inches]), two root pruning treatments (with or without copper coating), and 3 nitrogen levels (low to high) were grown for 29 weeks before they were outplanted into an open area in central Louisiana. Twenty-two months after outplanting, 3 seedlings were...

  5. Addressing post-transplant summer water stress in Pinus pinea and Quercus ilex seedlings

    Directory of Open Access Journals (Sweden)

    Pardos M

    2015-06-01

    Full Text Available In central Spain, post-transplant water stress produces high seedling mortality after the first summer following outplanting. Our study was designed to determine whether survival and performance of outplanted stone pine (Pinus pinea and holm oak (Quercus ilex seedlings in a burned area could be improved by summer irrigation and mulching and to identify whether there is a species-specific adaptive capacity to respond to treatment and environment. Seedlings were outplanted in March 2011 in 200 planting holes in an area of 1.1 ha. Mulch was added in June; irrigation started in July and was repeated every week until mid-September. The severity of the 2011 summer drought constrained growth rates and photosynthetic characteristics, mainly in the non-irrigated seedlings, whose survival at the end of the year after planting was approximately 2.5%. Stone pine and holm oak seedlings responded more to irrigation than to mulching in terms of shoot growth, biomass and survival. Furthermore, stone pine seedlings were found to be more responsive to the partial alleviation of summer drought than holm oak seedlings. Irrigation alone produced similar results to those obtained when both irrigation and mulching were employed. In conclusion, first year summer irrigation should be considered as a planned adaptation measure in the management of outplanted Mediterranean ecosystems, because once a gravimetrically measured soil moisture level as low as 2% is achieved seedling survival and physiological performance can be guaranteed. However, the repercussions for the potential persistence of both species in the area will not only be related to the recurrence and intensity of summer droughts but also to drought duration.

  6. Studies With Triazoles to Alleviate Drought Stress in GreenHouse-Grown Maize (Zea mays) Seedlings

    OpenAIRE

    Batlang, Utlwang

    2006-01-01

    In semi-arid environments, dry-land farming often exposes crops to drought stress. Although some plant species are well adapted to drought, most crops are not. Drought can reduce plant populations and limit growth and development in ways that have serious yield consequences. Planting at the beginning of the wet season, when rainfalls are often sporadic and unreliable, can expose young maize seedlings to severe drought. Through the use of plant growth regulators (PGR), maize seedlings can per...

  7. Short-term toxic effects of chlorobenzenes on broadbean (Vicia faba) seedlings.

    Science.gov (United States)

    Liu, Wan; Li, Peijun; Zhou, Qixing; Sun, Tieheng; Tai, Peidong; Xu, Huaxia

    2005-05-01

    The root growth, changes in superoxide dismutase (SOD, EC 1.15.1.1) activity, malonyldialdehyde (MDA) and total soluble protein level of broadbean (Vicia faba) seedlings were researched at different soil concentrations of chlorobenzene (CB), 1,2,4-trichlorobenzene (TCB) and hexachlorobenzene (HCB). The results showed that root growth of seedlings was interrupted after 5 d of 50-200 microg x g(-1) TCB treatment. During a 3 d recovery period, root growth was, however, restored to some extent although there was a delay in returning to the control level. The total soluble protein content in seedlings increased with TCB concentration and duration of exposure. Effect of TCB stress on SOD activity in seedlings displayed a significant dose-effect relationship for 1-5 d of 50-200 microg x g(-1) treatment. When broadbean seedlings were placed in clean tap water for 3 d following exposure to 5 d of TCB stress to clear tap water for 3 d, SOD activity at 50 microg x g(-1) TCB recovered towards control level (P>0.05) while a significant increase in SOD activity was observed at 100 and 200 microg x g(-1) TCB compared to control (P<0.05). The experiments also revealed that a significant increase of MDA level in seedlings occurred after 3 and 5 d of 100 and 200 microg x g(-1) TCB treatment (P<0.05 and P<0.01), and there was a positive correlation between TCB concentration and MDA level. All the above results showed that SOD activity and MDA level of broadbean seedlings might be proposed as the biomarkers for short-term TCB contamination in soil. Compared to TCB, the toxicity of 50-1000 microg x g(-1) CB or HCB in soil to broadbean seedlings was not observed after a 3 d exposure.

  8. Physiological responses of seedlings of two oak species to flooding stress

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The physiological responses of 2-year-old seedlings of Nuttall's oak (Quercus nuttalli) and Southern red oak (Q. falcata) with two treatments i.e., deep-drowning and shallow-drowning, were studied. Taxodium distichum was selected as a control. The survival rates of seedlings were calculated, the photosynthetic indices were detected by Licor-6400 photosynthetic system instrument,and the root activities of seedlings were tested by the method of triphenyltetrazolium chloride (TTC). Results showed that: 1) By experiencing flooding for 76 d and recovering for 60 d after water was drained off, all seedlings survived under the shallow-drowning treatment. None of Q. falcata seedlings died in the deep-drowning treatment until the 49th day. The survival rate of Q. falcata in the deep-drowning treatment was 30%. 2) Within 61 d of waterlogging treatments, the net photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) showed a tendency of declining, but intercellular concentration of CO2 (Ci) increased. With the pro-longation of flooding stress, the extents of variation for all indices under deep-drowning treatment were larger than those under the shallow-drowning treatment. The variation of Q. falcata in flooding stress was larger than that of Q. nuttallii. 3) The root vigor and alcohol dehydrogenase (ADH) activities were detected at the 61st day in flooding stress. Waterlogging obviously inhibited root ac-tivities. Shallow-drowning made root vigor of Q. nuttallii decreased by 11.7%, and for Q. falcata, by 51.88%. Shallow-drowning treatment had no remarkable effects on ADH activities of seedlings, but deep-&owning increased those of Q. nuttallii seedlings by 227.24%, and decreased those of Q. falcata seedlings by 59.22% in the meantime. We conclude that Q. nuttallii had a stronger wa-terlogging resistance than Q. falcata, but weaker than T. distichum.

  9. Araucaria cunninghamii Seedling Response to Different Forms and Rates of 15N-Labelled Fertiliser

    Institute of Scientific and Technical Information of China (English)

    T.J.BLUMFIELD; XU Zhi-Hong

    2006-01-01

    Nitrogenous fertilisers are under consideration for promoting the growth of nursery-reared hoop pine (Araucaria cunninghamii Aiton ex A. Cunn) seedlings in the establishment phase of second rotation (2R) plantations. Using 15Nlabelled fertilisers, we investigated the effect of different forms (ammonium sulphate, ammonium nitrate, potassium nitrate and urea) and rates of application (0, 150 and 300 mg N kg-1 dried soil) of fertilisers on the growth, 15N recovery and carbon isotope composition (δ13C) of hoop pine seedlings in a 12-month glasshouse trial in southeast Queensland,Australia. The 15N-labelled fertilisers were applied to nursery-reared hoop pine seedlings, which were then grown in pots,containing ca. 1.2 kg dried soil, under well watered conditions for 12 months. Four seedlings from each treatment were harvested at 4-month intervals, divided into roots, stem and foliage, with a further subdivision for new and old foliage,and then analysed for 15N, total N, δ13C and total C. There was no significant response in the seedling growth to the form or rate of application of nitrogen (N) fertiliser within the 12-month period, indicating that the seedlings did not experience N deficiency when grown on second rotation hoop pine soils. While the combined 15N recovery from soil and plant remained at around 70% throughout the experiment, the proportion of 15N recovered from the plants increasing steadily over time. Nitrate containing fertilisers at 150 mg N kg-1 soil gradually increased seedling foliage δ13C over the 12-month period, indicating an increase in seedling water use efficiency.

  10. Response of barley seedlings to oxidative stress generated by treatments with growth hormones

    OpenAIRE

    Zenovia Olteanu; Elena Truta; Lacramiora Oprica; Maria Magdalena Zamfirache

    2009-01-01

    The effects induced by growth hormone regulators on soluble protein level and some oxidoreductases in Hordeum vulgare cv. Madalin seedlings were investigated. The study of superoxide dismutase, catalyse and peroxidase behaviour and of protein synthesis was realized in dynamics to evaluate the response of barley seedlings to oxidative stress generated by exposure to hormone factors. During experiments, peroxidase registered smaller limits of variability than superoxide dismutase an...

  11. Magnetic field can alleviate toxicological effect induced by cadmium in mungbean seedlings.

    Science.gov (United States)

    Chen, Yi-ping; Li, Ran; He, Jun-Min

    2011-06-01

    To alleviate toxicological effect induced by cadmium in mungbean seedlings, seeds were divided into four groups: The controls groups (CK, without treatment), magnetic field treated groups (MF), cadmium treated groups (CS), and magnetic field treated followed by cadmium treated groups (MF + CS).The results showed: (i) Compared with the controls, cadmium stress resulted in enhancing in the concentration of malondialdehyde, H(2)O(2) and O(2-), and the conductivity of electrolyte leakage while decreasing in the nitrice oxide synthase (NOS) activity, the concentration of nitrice oxide (NO), chlorophyll and total carbon and nitrogen, the net photosynthetic rate, the stomatal conductance, the transpiration rate, the water use efficiency, the lateral number and seedlings growth except for intercellular CO(2) concentration increase. However, the seedlings treated with 600 mT magnetic field followed by cadmium stress the concentration of malondialdehyde, H(2)O(2) and O(2-), and the conductivity of electrolyte leakage decreased, while the above mentioned NO concentration, NOS activity, photosynthesis and growth parameters increased compared to cadmium stress alone. (ii) Compared with the cadmium stress (CS), the seedling growth were inhibited when the seeds were treated with NO scavenger (hemoglobin, HB) and inhibition of NO generating enzyme (sodium tungstate, ST), conversely, the seedling growth were improved by the NO donor sodium nitroprusside (SNP) and CaCl(2). In the case of the HB and ST treatment followed by magnetic field and then the seedling subjected to CS, the seedlings growth was better than that of hemoglobin (HB) followed by CS and ST followed by CS. The seeds were treated with SNP and CaCl(2) followed by MF, and then subjected to CS, the seedlings growth were better than that of SNP followed by CS, and CaCl(2) followed by CS. These results suggested that magnetic field compensates for the toxicological effects of cadmium exposure are related to NO signal.

  12. Performance of northern red oak seedlings across a pH gradient

    Science.gov (United States)

    Anthony S. Davis; Douglass F. Jacobs

    2005-01-01

    Northern red oak (Quercus rubra L.) seedlings were grown from acorns in 4-gallon containers in a greenhouse. Growing medium was amended to a pH of 3.50, 4.25, 5.00, and 5.75 using tri-weekly applications of aluminum sulfate. In addition, seedlings were subjected to either: (1) addition of a 16- to 18-month controlled release fertilizer (CRF), (2)...

  13. Production of gherkin seedlings in coconut fiber fertirrigated with different nutrient solutions

    OpenAIRE

    Francisco de Assis Oliveira; Maria da Saúde de Souza Ribeiro; Mychelle Karla Teixeira de Oliveira; Daniele Campos Martins; Maria Lilia de Souza Neta; José Francismar de Medeiros

    2016-01-01

    ABSTRACT Seedling quality is a key factor to achieve success in vegetable production. The present work aimed to evaluate the production of gherkin seedlings in substrate of coconut fiber fertirrigated with different concentrations of nutrients. The experimental design was completely randomized in a 3 × 5 factorial with four replications. The treatments consisted of combinations of three cultivars of gherkin (Do Norte, Liso de Calcutá, e Liso Gibão) with five concentrations of nutrients in th...

  14. Seedling-nursing technique for olive%橄榄树育苗技术

    Institute of Scientific and Technical Information of China (English)

    叶倩倩

    2015-01-01

    总结橄榄树育苗技术,主要包括品种选择、育苗方法、幼苗培育和管理、嫁接方法等方面内容。%Seedling-nursing technique for olive were summarized in this paper,including variety selection,breeding way, seedling cultivation and management,grafting method,etc.

  15. Effect of mycorrhizae o f pine seedlings on the utilization of different mineral phosphorus sources

    Directory of Open Access Journals (Sweden)

    Roman Pachlewski

    2014-08-01

    Full Text Available Pine seedlings (P. sylvestris L. growing on the unsterilized sand, with addition of different phosphorus sources, were inoculated with ectomycorrhizal fungi. Lack of P in the substrate restricted mycorrhizal infection of roots. In the presence of AIPO4 and FePO4 inoculation with A. verna and H. mesophaeum have positive effect on the seedlings growth and survival. Strain of H. mesophaeum intensified the phosphorus uptakc, particulary when FePO4 was applied.

  16. Growth and nutrient balance of Enterolobium contortsiliquum seedlings with addition of organic substrates and wastewater

    Directory of Open Access Journals (Sweden)

    Emanuel França Araújo

    2016-06-01

    Full Text Available Given the strong generation of solid organic waste and wastewater, the use of these materials as a primary source of nutrients is an important practice in environmental management, especially in the production of seedlings with emphasis on degraded areas. The objective of this study was to evaluate growth and nutrient balance of “tamboril” (Enterolobium contortsiliquum (Vell. Morong seedlings grown on substrates with different formulations proportions of organic matter irrigated with wastewater. It was tested five ratios of organic composts and soil: 0:100; 20:80; 40:60; 60:40 and 80:20 v/v. Two procedences of irrigation water was tested: water supply and wastewater from swine farming, arranged in a completely randomized design in a factorial scheme 5 x 2, with four replications. At 90 days, we evaluate seedlings morphological variables, the integrate diagnosis recommendation index and the nutrient balance index. The organic residue contributes to seedlings growth and nutritional balance. The proportion 80:20 proved to be the most suitable for “tamboril” seedlings production. Seedlings presented lower growth and nutritional balance when irrigate with swine farm wastewater.

  17. Effects of aluminum on growth, development, and nutrient composition of honeylocust (Gleditsia triacanthos L.) seedlings.

    Science.gov (United States)

    Thornton, F. C.; Schaedle, M.; Raynal, D. J.

    1986-12-01

    Hydroponic experiments were conducted to determine the effects of aluminum (Al) on root development, shoot morphology and the nutrient composition of honeylocust seedlings (Gleditsia triacanthos L.). Seedlings were grown at pH 4 in a nutrient solution containing 0, 50, 150, 600 or 1500 microM Al. Within seven days, there were significant differences in root growth and root nutrient composition between control seedlings and seedlings grown in the presence of 150 or 600 microM Al. By day 14, significant reductions in leaf production and plant height were observed in seedlings treated with 1500 microM Al. At the lowest Al concentration, 50 microM, leaf size and expansion rates were significantly lower than in the controls. By the third week of the experiment, Ca and Mg concentrations in young leaves of the Al-treated seedlings were significantly lower than in leaves of control plants. Analysis of old leaf tissue, however, revealed no consistent pattern of nutrient concentration with Al treatment.

  18. Growth and photosynthetic responses of ectomycorrhizal pine seedlings exposed to elevated Cu in soils.

    Science.gov (United States)

    Chen, Yahua; Nara, Kazuhide; Wen, Zhugui; Shi, Liang; Xia, Yan; Shen, Zhenguo; Lian, Chunlan

    2015-10-01

    It is still controversial whether ectomycorrhizal (ECM) mycelia filter out toxic metals in nutrient absorption of host trees. In this study, pine (Pinus densiflora) seedlings colonized by Cu-sensitive and Cu-tolerant ECM species were exposed to a wide spectrum of soil Cu concentrations to investigate functions of ECM fungi under Cu stress. The photosynthetic rates of intact needles were monitored in situ periodically. The biomass and elements of plants were also measured after harvest. The ameliorating effect of ECM infection on host plants exposed to toxic stress was metal concentration specific. Under lower-level Cu stress, ECM fungi increased seedling performance, while ECM seedlings accumulated more Cu than nonmycorrhizal (NM) seedlings. Under higher-level Cu stress, photosynthesis decreased well before visible symptoms of Cu toxicity appeared. The reduced photosynthesis and biomass in ECM seedlings compared to NM seedlings under higher Cu conditions were also accompanied by lower phosphorus in needles. There was no marked difference between the two fungal species. Our results indicate that the two ECM fungi studied in our system may not have an ability to selectively eliminate Cu in nutrient absorption and may not act as effective barriers that decrease toxic metal uptake into host plants.

  19. Reforestation of bauxite mine spoils with Eucalyptus tereticornis Sm. seedlings inoculated with arbuscular mycorrhizal fungi

    Directory of Open Access Journals (Sweden)

    N. Krishnakumar

    2012-11-01

    Full Text Available Open cast mining for bauxite at Yercaud hills (India resulted indegradation of forest ecosystem and production of large quantities of waste rocks (called mine spoils. To ameliorate mine spoils, topsoil is used to spread over before the planting of tree species, conventional method as the topsoil has a good structure, water holding capacity and beneficial microbes like Arbuscular Mycorrhizal (AM fungi essential for plant growth.However, the use of top soil is expensive and in this study bauxite mine spoils were reforestated with AM fungi instead of it. The beneficial microbes AM fungi (Glomus aggregatum Schenck & Smith, G. fasciculatum(Thatcher Gerd. & Trappe emend. Walker & Koske, G. geosporum(Nicol. & Gerd. Walker were isolated, cultured and inoculated into the seedlings of Eucalyptus tereticornis Sm. and grown in bauxite mine spoils as potting medium under nursery conditions. Then, the biomass improved seedlings of E. tereticornis with inoculation of AM fungi were directly transplanted at bauxite mine spoils. After transplantation of the seedlings at bauxite mine spoils, the growth and survival rate were monitored for two years. The AM fungi inoculated seedlings of E. tereticornis showed 95% survival over the control seedlings and their growth was also significantlyhigher. Tissue nutrients (N, P, K were also found higher inAM fungi inoculated E. tereticornis than un inoculated control seedlings.

  20. Seed germination and seedling growth of two Pseudobombax species (Malvaceae) with contrasting habitats from Brazilian Cerrado.

    Science.gov (United States)

    Mendes-Rodrigues, Clesnan; Oliveira, Paulo Eugênio; Ranal, Marli Aparecida

    2011-12-01

    Pseudobombax tomentosum and P. longiflorum are common trees in the Cerrado region, but the former species is more common in forest edges while the later is present in open cerrado areas. This work aimed to investigate differences in seed germination and seedling growth in these species, from seed collected from Cerrado areas in Central Brazil. For this, a seed germination experiment was designed and included four replicates with 25 seeds per species; seeds were randomly distributed in the germination chamber. To evaluate initial seedling growth, seedlings height was measured up to 67 days after seedling emergence; besides, some of these seedlings were grown for biomass evaluation during nine months. Results showed that seeds of the two species had the same germinability (near 100%) and mean germination time (ca. 12 days). However, P. longiflorum showed a more spread seed germination through time, with higher values of coefficient of variation in germination time and uncertainty index; and lower values of synchronization than P. tomentosum. The two species showed basically the same growth pattern, but lower values for height of apical meristem, diameter of underground structures (mostly roots), dry mass of shoots, underground structure and total mass of seedlings in P. tomentosum were obtained, compared to P. longiflorum. Both species allocated more dry mass to underground structures in detriment of shoot. This probably allows resprouting behavior which prevents hydric stress and detrimental fire action typical of the open Cerrado areas.

  1. Higher-order interaction between molluscs and sheep affecting seedling numbers in grassland

    Science.gov (United States)

    Clear Hill, B. H.; Silvertown, J.

    Vertebrate and invertebrate herbivores are both important in mesotrophic grasslands and these two different classes of herbivore potentially interact in their effect upon plant populations. We used two field experiments to test for higher order interactions (HOIs) among sheep, slugs and seedlings, using the mechanistic definition that an HOI occurs when the presence of one species modifies the interaction between two others. In each experiment slug addition and slug-removal treatments were nested inside treatments that altered sheep grazing intensity and timing, and the emergence, of seedlings from experimentally sown seeds was monitored. In Experiment 1, seedling numbers of Cerastium fontanum were increased by intense summer grazing by sheep in both slug-addition and slugremoval treatment, but winter grazing by sheep only increased seedling emergence if slugs were removed. In Experiment 2, winter grazing by sheep significantly reduced total seedling emergence of four species sown ( Lotus corniculatus, Plantago lanceolata, Leucanthemum vulgare, Achillea millefolium), but the effect was only seen where slugs were removed. Though the experimental system is a relatively simple one with only four components (sheep, slugs, seedlings and the matrix vegetation), higher order interactions, a combination of direct and indirect effects and possible switching behaviour by slugs are all suggested by our results.

  2. Pondberry (Lindera   melissifolia, Lauraceae seed and seedling dispersers and predators

    Directory of Open Access Journals (Sweden)

    Andreza M. Martins

    2015-07-01

    Full Text Available Pondberry (Lindera melissifolia(Walter Blume is an endangered dioecious, clonal shrub that grows in periodically flooded forests of the southeastern United States. The probability of survival of dispersed pondberry seeds and new germinants is unknown, but few seedlings are noted in the forest. This study was undertaken to: (1 identify herbivores and predators of pondberry seeds and seedlings, (2 record the fate of pondberry seeds and seedlings after simulated dispersal in areas with lower and higher understory cover, and (3 calculate the probability of seed survival in the two cover types. The study was conducted in or near the Delta National Forest and the Delta Experimental Forest, MS. Pondberry seed and seedling plots were established at sites with high or low cover. Video cameras with infrared illumination were set up to monitor animal visitors to the plots. Image analysis indicated that swamp rabbits (Sylvilagus aquaticus (Bachman and wood rats (Neotoma floridana Ord cut or ate seedlings, while other animals visited the plots without damaging seedlings. Numerous bird species and mammals visited the seed plots and some were filmed eating seeds. Pondberry seeds exposed in open habitats had a significantly higher survival rate than those exposed in habitats with more herbaceous and woody understory cover. The novelty and quality of the temporal data collected via video monitoring indicate the importance of this method in collecting data that are not otherwise available on endangered and rare species.

  3. Interactive effects of rice residue and water stress on growth and metabolism of wheat seedlings

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    Nimisha Amist

    2014-08-01

    Full Text Available In the present study effects of rice residue with and without water stress were studied on Triticum aestivum L. cv. Shatabadi. The mixture of residue and garden soil in 1:1 ratio was considered as 50% (R1 and only decomposed residue as 100% (R2. Garden soil was taken as control. Twenty five seeds were sown in each experimental trays filled with soil mixture according to the treatments. Trays were arranged in two groups. After 15 days one set was subjected to water stress (WS by withholding water supply for 3 days. Morphological and biochemical parameters of 18 days old seedlings were recorded. Seedling height decreased in all treatments. A gradual decrease in relative water content, pigment and protein contents of wheat seedlings were observed. Sugar and proline contents increased in treatments. An increase in malondialdehyde (MDA content and antioxidative enzyme activities was recorded. Elevation in catalase activity was observed in all treatments except in plants with water deficit. Ascorbate peroxidase (APX and guaiacol peroxidase (GPX activities increased when residue mixed with soil but decreased in seedlings under the combined influence of the residue and water stress. Higher amount of MDA and lower activities of APX and GPX reflected the oxidative damage in seedlings under combined treatments. Rice residue inhibited growth of wheat seedlings. Water stress intensified the effects of residue.

  4. [Response of leaf anatomical characteristics of Cyclobalanopsis gilva seedlings to drought stress].

    Science.gov (United States)

    Wu, Li-jun; Li, Zhi-hui; Yang, Mo-hua; Wang, Pei-lan

    2015-12-01

    In this study, the leaf anatomical characteristics and transpiration rate of one-year-old seedlings from three study areas including Qingyuan of Zhejiang Province, Dongkou and Jingzhou of Hunan Province were investigated using a pot planting experiment in which relative soil water content was kept as 75%-80% (control), 55%-60% (mild drought stress), 45%-50% (moderate drought stress), 30%-35% (severe drought stress), respectively. The results showed that drought stress significantly reduced the total thickness of the seedling leaves, the thickness of their upper and lower epidermis and the thickness of palisade tissue. The ratio of the palisade tissue to spongy tissue, stomatal length and width also decreased significantly, while the stomatal density increased significantly as the drought stress became more intense. The treatments of drought stress had no significant effect on the thickness of the main veins of the leaves although their xylem thickness varied depending on the seedlings from the different study sites. The change of leaf structure caused the change of physiological function. As drought stress was intensified, the transpiration rate of C. gilva seedlings decreased significantly. The ratio of the palisade tissue to spongy tissue, the thickness of the lower epidermis and stomatal density of the seedlings from Dongkou of Hunan Province were significantly greater, while the transpiration rate was significantly lower than those from other two study sites for all the drought stress treatments, implying that the C. gilva seedlings from Dongkou of Hunan Province had a stronger drought-resistance ability.

  5. Biocontrol of Phytophthora infestans, Fungal Pathogen of Seedling Damping Off Disease in Economic Plant Nursery

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    B. Loliam

    2012-01-01

    Full Text Available This research aims to control Seedling damping off disease in plants by using antagonistic actinomycetes against the causative fungi. Phytophthora infestans was isolated from the infected tomato plant seedling obtained from an economic plant nursery in Amphoe Pak Chong, Nakhon Ratchasima Province, Thailand. The chitinolytic Streptomyces rubrolavendulae S4, isolated from termite mounds at the grove of Amphoe Si-Sawat, Kanchanaburi Province, Thailand, was proven to be the most effective growth inhibition of fungal pathogens tested on potato dextrose agar. Tomato and chili seedlings that colonized with antagonistic S. rubrolavendulae S4 were grown in P. infestans artificial inoculated peat moss. Percents of noninfested seedling in fungal contaminated peat moss were compared to the controls with uninoculated peat moss. In P. infestans contaminated peat moss, the percents of survival of tomato and chili seedling were significantly increased (0.05. It was clearly demonstrated that S. rubrolavendulae S4 can prevent the tomato and chili seedling damping off disease in economic plant nurseries.

  6. Short Communication. Physiological effects of Rhizopogon Roseolus on Pinus halepensis seedlings

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    J.A. Alfonso Domínguez Núñez

    2013-12-01

    Full Text Available Aim of study: The inoculation of forest seedlings with ectomycorrhizal fungi can improve the morphological and physiological qualities of plants, especially those used for regeneration of arid areas. Rhizopogon roseolus is an ectomycorrhizal fungus (ECM commonly used for reforestation. In this study, the specific objectives were to know some morphophysiological effects of Rhizopogon Roseolus on Pinus halepensis seedlings under standard nursery conditionsArea of study: ETSI Montes and EUIT Forestal, Madrid.Material and Methods: In nursery, under well watered conditions and peat growing substrates, Aleppo pine seedlings were inoculated with R. roseolus. Five months after the inoculations, we examined the growth, water parameters (osmotic potential at full turgor [Ψπfull], osmotic potential at zero turgor [Ψπ0], and the tissue modulus of elasticity near full turgor [Emax], mycorrhizal colonization, and concentration and content of macronutrients in the seedlings. Subsequently, a trial was conducted to assess the root growth potential.Main results: The mycorrhization decreased the height and diameter of mycorrhizal seedlings but increased the root weight and root branching. R. roseolus did not cause any significant effect on the regeneration of new roots or on any of the tested hydric parameters, but it did improve N uptake of the seedlings.Research highlights: The mycorrhizal inoculation increased the N uptake. The mycorrhizal inoculation caused opposite effects on some growth parametersKeywords: Osmotic adjustment; elastic adjustment; mineral nutrition; root growth potential; nursery; Rhizopogon roseolus;  Pinus halepensis. 

  7. Influence of microhabitat on seedling survival and growth of the mediterranean seagrass posidonia oceanica (l.) Delile

    Science.gov (United States)

    Alagna, Adriana; Fernández, Tomás Vega; Terlizzi, Antonio; Badalamenti, Fabio

    2013-03-01

    Early life history phases are crucial stages limiting species distribution and abundance, thus influencing assemblage composition in marine benthic environments. In seagrass systems the period between seed germination and establishment is one of the most vulnerable phases for plant development. This study analyzes the influence of microhabitat structure, in terms of substrate nature and algal canopy, on the persistence and growth over two years of seedlings of Posidonia oceanica, the dominant Mediterranean seagrass. Long time persistence of seedlings only occurred on microhabitats providing vegetated rocky substrates, with a maximum value of 81% on rock covered by Cystoseira spp. No seedling was found on unvegetated sand and gravel after the first year. Seedling growth resulted increased on rock covered by Halopteris spp. and Dilophus spp. than on rock covered by Cystoseira spp. Results suggest that high canopy onto a stable substrate enhances seedling persistence, probably because these allow the best anchorage by roots while hampering water flow. In contrast, turf algal cover promotes better seedling growth, possibly through higher light irradiance and nutrient availability. Our findings support the view that the understanding of the factors controlling early life processes is a necessary prerequisite for the comprehension of seagrass species distribution patterns, colonization and recovery potentials, which, in turn, can guide sound strategies for seagrass management and restoration.

  8. ORIGIN OF ORGANIC SUBSTRATES FOR PRODUCTION OF SEEDLINGS OF TEAK (Tectona grandis Linn. F.

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    Paulo André Trazzi

    2013-08-01

    Full Text Available http://dx.doi.org/10.5902/1980509810551The utilization of renewable waste as a source of nutrients for forest seedlings production can be a solution to environmental problems, mainly related to the disposal of these materials. In this context, this study aimed to evaluate the use of renewable substrates as substrate components in the production of teak seedlings. Seedlings were grown in tubes with a volume capacity of 280 cm³, using for the composition of treatments cattle manure, poultry litter or manure quail associated with subsoil earth and a fraction of 25% of commercial forestry substrate, and the formed substrates were subjected to chemical analysis. Ninety days after transplanting the seedlings, the following morphological characteristics were analyzed: shoot height, stem diameter, dry weight of shoots, roots and total and Dickson quality index. The results indicated that the seedlings produced with substrates formulated with poultry litter had the highest growth from the traits studied, given that the treatment with 35% of this material provided the greatest gains. The use of renewable substrates may be indicated for forest seedling production, contributing for the improvement of the chemical properties of substrates formed and consequently for the plant nutrition.

  9. The Potential for Cereal Rye Cover Crops to Host Corn Seedling Pathogens.

    Science.gov (United States)

    Bakker, Matthew G; Acharya, Jyotsna; Moorman, Thomas B; Robertson, Alison E; Kaspar, Thomas C

    2016-06-01

    Cover cropping is a prevalent conservation practice that offers substantial benefits to soil and water quality. However, winter cereal cover crops preceding corn may diminish beneficial rotation effects because two grass species are grown in succession. Here, we show that rye cover crops host pathogens capable of causing corn seedling disease. We isolated Fusarium graminearum, F. oxysporum, Pythium sylvaticum, and P. torulosum from roots of rye and demonstrate their pathogenicity on corn seedlings. Over 2 years, we quantified the densities of these organisms in rye roots from several field experiments and at various intervals of time after rye cover crops were terminated. Pathogen load in rye roots differed among fields and among years for particular fields. Each of the four pathogen species increased in density over time on roots of herbicide-terminated rye in at least one field site, suggesting the broad potential for rye cover crops to elevate corn seedling pathogen densities. The radicles of corn seedlings planted following a rye cover crop had higher pathogen densities compared with seedlings following a winter fallow. Management practices that limit seedling disease may be required to allow corn yields to respond positively to improvements in soil quality brought about by cover cropping.

  10. Photosynthetic induction responses of Pinus koraiensis seedlings grown in different light environments

    Institute of Scientific and Technical Information of China (English)

    ZHOUYong-bin; YINYou; LIUXing-shuang; WANGQing-li

    2004-01-01

    The time processes of photosynthetic induction responses to various irradiances in Korean pine (Pinus koraiensis) seedlings grown in open-light environments and in understory of forest were studied in an area near the Research Station of Changbai Mountain Forest Ecosystems, Jilin Province, China from July 15 to August 5, 1997. The results showed that at 200 IJmol·m-2·s-1 photosynthetic photon flux density (PPFD) and 500 pmol·m-2·s-1 PPFD, the induction time for the photosynthetic rates of understory-grown seedlings to reach 50% and 90% steady-state net photosynthetic rates was longer than that of the open-grown seedlings. The induction responses of open-growth seedlings at 500 pmol·m-2·s-1 PPFD were slower than those at 200 pmol·m-2·s-1 PPFD, but it was the very reverse for understory-growth seedlings, which indicates that the photosynthetic induction times of Korean pine seedlings grown in the understory depended on the sunfleck intensity.

  11. On hybridising lettuce seedlings with nanoparticles and the resultant effects on the organisms' electrical characteristics.

    Science.gov (United States)

    Gizzie, Nina; Mayne, Richard; Patton, David; Kendrick, Paul; Adamatzky, Andrew

    2016-09-01

    Lettuce seedlings are attracting interest in the computing world due to their capacity to become hybrid circuit components, more specifically, in the creation of living 'wires'. Previous studies have shown that seedlings can be hybridised with gold nanoparticles and withstand mild electrical currents. In this study, lettuce seedlings were hybridised with a variety of metallic and non-metallic nanomaterials: carbon nanotubes, graphene oxide, aluminium oxide and calcium phosphate. Toxic effects and the following electrical properties were monitored: mean potential, resistance and capacitance. Macroscopic observations revealed only slight deleterious health effects after administration with one variety of particle, aluminium oxide. Mean potential in calcium phosphate-hybridised seedlings showed a considerable increase when compared with the control, whereas those administered with graphene oxide showed a small decrease; there were no notable variations across the remaining treatments. Electrical resistance decreased substantially in graphene oxide-treated seedlings whereas slight increases were shown following calcium phosphate and carbon nanotubes applications. Capacitance showed no considerable variation across treated seedlings. These results demonstrate that use of some nanomaterials, specifically graphene oxide and calcium phosphate, may be towards biohybridisation purposes including the generation of living 'wires'.

  12. Methods of studying field germination and seedling physiology: present potential and drawbacks

    Directory of Open Access Journals (Sweden)

    Hanne N. Rasmussen

    2012-02-01

    Full Text Available Seed germination and seedling growth are equally important processes for population survival. Observation of germinating orchid seeds in a natural substrate is inhibited by their minute size. There are basically two approaches to studying germination in situ: Search for spontaneous seedlings, and field sowing experiments; these may be supplemented with experiments in vitro. Finds of spontaneous seedlings are clearly irregular and fortuitous but may yield valuable, if fragmentary, input to hypothesis building. An understanding of the habitat dynamics may be helpful in the search of such seedlings. The seed package technique for germination in situ and its various adaptations can yield considerable information concerning spatial distribution and timing, identity of participating fungi, seedling growth rate and stimulatory environmental conditions. This approach constitutes the backbone to studies of germination ecology and still holds much unexplored potential. However, conditions that are suitable for orchid seed germination in nature are not necessarily identical to those supporting adult plant growth. Experiments in vitro on artificial substrate normally employs either immature or strongly surface sterilized seeds, and thus the results can be misleading regarding the behavior of natural seeds and seedlings in the field. However, such experiments may be designed for added information on specific questions, provided that growth conditions are manipulated suitably. Experiments in vitro, especially symbiotic and on series of minimal media, have much to offer in supporting and extending field observations of substrate and site preferences.

  13. Within-population variability influences early seedling establishment in four Mediterranean oaks

    Science.gov (United States)

    González-Rodríguez, Victoria; Barrio, Isabel C.; Villar, Rafael

    2012-05-01

    Regeneration of Mediterranean forests is severely limited. Multiple abiotic factors are known to constrain the establishment of woody seedlings at its first phases, such as summer drought or excessive incident radiation, but less attention has been paid to the role of intra-specific variation in seedling performance. In this study we investigate the relative influence of environment (light availability, soil moisture and summer irrigation) and intrinsic factors (seed mass and maternal origin) as determinants of within-population variability in the early establishment of four coexisting Mediterranean oaks (Quercus ilex, Quercus suber, Quercus faginea and Quercus pyrenaica), from emergence and early growth to second-year survival in a field experiment. Seed size was a poor predictor of seed and seedling success. Instead, mother identity showed a stronger effect on seedling performance. Time and percentage of emergence, establishment success and morphological traits varied among seedlings from different maternal trees but main drivers for each variable were different for each species. In addition to a direct effect, in many cases mother-related intrinsic traits and seed mass influenced the effects of environmental conditions on seedling performance. The role of intrinsic factors was masked under ameliorated conditions (i.e. summer irrigation), indicating the relevant role of within-population variability to cope with highly heterogeneous and unpredictable Mediterranean environments.

  14. Maternal influences on seed mass effect and initial seedling growth in four Quercus species

    Science.gov (United States)

    González-Rodríguez, Victoria; Villar, Rafael; Navarro-Cerrillo, Rafael M.

    2011-01-01

    Seed mass represents the reserves available for growth in the first stages of plant establishment. Variation in seed mass is an important trait which may have consequences for growth and survival of seedlings. Three mechanisms have been proposed to explain how seed mass influences seedling development: the reserve use effect, the metabolic effect and the seedling-size effect. Few studies have evaluated at the same time the three hypotheses within species and none have evaluated the effect of the mother trees. We studied four Quercus species by selecting five mother trees per species. Seeds were sown in a glasshouse and the use of seed reserves, seedling growth and morphology were measured. Considering all mothers of the same species together, we did not find the reserve effect for any species, the metabolic effect was observed in all species except for Quercus suber, and the seedling-size effect was matched for all the species. Within species, maternal origin modified the studied relationships and thus the studied mechanisms as we did not observe seed mass effects on all mothers from each species. Moreover, the metabolic effect was not found in any mother of Quercus ilex and Quercus faginea. We concluded that a maternal effect can change seed mass relationships with traits related to seedling establishment. The conservation of this high intra-specific variability must be considered to guarantee species performance in heterogeneous environments and in particular in the current context of climate change.

  15. Properties of Plasma Membrane from Pea Root Seedlings under Altered Gravity

    Science.gov (United States)

    Klymchuk, D.; Baranenko, V.; Vorobyova, T. V.; Kurylenko, I.; Chyzhykova, O.; Dubovoy, V.

    In this study, the properties of pea (Pisum sativum L.) plasma membrane were examined to determine how the membrane structure and functions are regulated in response to clinorotation (2 rev/min) conditions. Membrane preparations enriched by plasma membrane vesicles were obtained by aqueous two-phase partitioning from 6-day seedling roots. The specific characteristics of H^+-ATPase, lípid composition and peroxidation intensity as well as fluidity of lipid bilayer were analysed. ATP hydrolytic activity was inhibited by ortovanadate and was insensitive to aside and nitrate in sealed plasma membrane vesicles isolated from both clinorotated and control seedlings. Plasma membrane vesicles from clinorotated seedlings in comparison to controls were characterised by increase in the total lipid/protein ratio, ATP hydrolytic activity and intensifying of lipid peroxidation. Sitosterol and campesterol were the predominant free sterol species. Clinorotated seedlings contained a slightly higher level of unsaturated fatty acid than controls. Plasma membrane vesicles were labelled with pyrene and fluorescence originating from monomeric (I_M) molecules and excimeric (I_E) aggregates were measured. The calculated I_E/I_M values were higher in clinorotated seedlings compared with controls reflecting the reduction in membrane microviscosity. The involvement of the changes in plasma membrane lipid content and composition, fluidity and H^+-ATPase activity in response of pea seedlings to altered gravity is discussed.

  16. Quantitative dynamics on stimulating regeneration and sowing seedlings of Larix gmelinii in Daxing'an Mountains

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    To understand the quantitative dynamics and death reason of stimulating regeneration seedlings is significant for stimulating the natural regeneration of Larix gmelinii and implement of conservation project of natural forest. This paper summarized location observations and directly-seeding simulation experiments of six permanent sample plots that were set up after the seed bumper harvest year of Larix gmelinii in 1989. The study showed that stimulating natural regeneration seedlings had a large mortality in the first three years, especially in the first year of seedling emergence. After three years seedlings died less and stepped into the stable regeneration stage. A large number of seedlings died of sunscald as the primary death reason. For those areas of good site conditions and rich soil, damping-off would cause seedlings to death in large quantities. The task of stimulating regeneration is mainly to get rid of the litter (forest floor) on burned areas. By means of promoting measures, emergence rate of sown seeds would be several times and dozens of times higher than that of seed shedding on the condition of retention of forest floor. Promoting the regeneration need to select the suitable site against great slope and low-lying lands; at the same time, be careful of the avoidance of frost heaving by depression water.

  17. Seed Priming with Selenium: Consequences for Emergence, Seedling Growth, and Biochemical Attributes of Rice.

    Science.gov (United States)

    Khaliq, Abdul; Aslam, Farhena; Matloob, Amar; Hussain, Saddam; Geng, Mingjian; Wahid, Abdul; ur Rehman, Hafeez

    2015-08-01

    The present study was undertaken to appraise the role of selenium priming for improving emergence and seedling growth of basmati rice. Seeds of two fine rice cultivars (Super and Shaheen Basmati) were primed with concentrations of 15, 30, 45, 60, 75, 90, and 105 μmol L(-1) selenium. Untreated dry- and hydro-primed seeds were maintained as the control and positive control, respectively. Selenium priming resulted in early commencement of emergence, triggered seedling growth irrespective of rice cultivar over untreated control, and was more effective than hydro-priming except at higher concentrations. Lower electrical conductivity of seed leachates, reduced lipid peroxidation, greater α-amylase activity, higher soluble sugars, and enhanced activities of enzymatic antioxidants (superoxide dismutase (SOD), peroxidase (POX), catalase (CAT), and glutathione peroxidase (GPX)) were observed in seeds primed with selenium. Rice seedlings derived from selenium-primed seeds exhibited more chlorophyll contents, while total phenolics were comparable with those of the control seedlings. The improved starch metabolism, greater membrane stability, and increased activity of antioxidants were considered as possible mechanisms responsible for such improvements in emergence and seedling vigor of rice mediated by selenium priming. Priming with selenium (15-60 μmol L(-1)) favored rice emergence and seedling growth. Nevertheless, soaking seeds in relatively concentrated (90 and 105 μmol L(-1)) selenium solution had overall detrimental effects.

  18. Elevational Distribution of Adult Trees and Seedlings in a Tropical Montane Transect, Southwest China

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    Xiaoyang Song

    2016-08-01

    Full Text Available Montane habitats are characterized by high variation of environmental factors within small geographic ranges, which offers opportunities to explore how forest assemblages respond to changes in environmental conditions. Understanding the distributional transition of adult trees and seedlings will provide insight into the fate of forest biodiversity in response to future climate change. We investigated the elevational distribution of 156 species of adult trees and 152 species of seedlings in a tropical montane forest in Xishuangbanna, southwest China. Adult trees and seedlings were surveyed within 5 replicate plots established at each of 4 elevational bands (800, 1000, 1200, and 1400 m above sea level. We found that species richness of both adult trees and seedlings changed with elevation, showing a notable decline in diversity values from 1000 to 1200 m. Tree species composition also demonstrated distinct differences between 1000 and 1200 m, marking the division between tropical seasonal rain forest (800 and 1000 m and tropical montane evergreen broad-leaved forest (1200 and 1400 m. The results suggested that soil moisture and temperature regimes were associated with elevational distribution of tree species in this region. We also observed that seedlings from certain species found at high elevations were also distributed in low-elevation zones, but no seedlings of species from low elevations were distributed in high-elevation zones. The increase in temperature and droughts predicted for this region may result in the contraction of tropical seasonal rain forest at lower elevations and a downhill shift of higher tropical montane tree species.

  19. SEEDLINGS ESTABLISHMENT OF Eucalyptus grandis MYCORRHIZATED WITH Pisolithus microcarpus (UFSC Pt 116 IN SANDY SOIL

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    Andréa Hentz de Mello

    2009-09-01

    Full Text Available The aim of this work was to evaluate the survival and the initial growth of mycorrhizated eucalypts with Pisolithus microcarpus (UFSC Pt 116 ectomycorrhizal fungus, after its transplant to area subject to the arenization process in São Francisco de Assis, RS. The area was divided into four blocks, each one with four treatments (fertile turf with and without mycorrhizae, Quartzarenic Neosoil with and without mycorrhizae. Each parcel was composed of 16 seedlings arranged in four lines in the spacing of 1,5 m x 1,5 m, totalizing in each block 64 seedlings. 90 days after the planting in the field, the eucaliptus seedlings produced in turf with fungus in the fertile substratum presented a survival rate of 100 %, whereas for those produced in fertile turf without fingi, the survival rate was 92 %. The seedlings produced in the Quartzarenic Neosoil with and without mycorrhizae had a survival rate varying around 98 and 89 %, respectively. The produced seedlings with turf and fungus showed significant differences in height and stem diameter. This study showed that the Eucalyptus grandis seedlings produced in substratum fertile turf and inoculated with the Pisolithus microcarpus (UFSC Pt 116 isolated may maintain good development and establishment in the field.

  20. Identification of embryo proteins associated with seed germination and seedling establishment in germinating rice seeds.

    Science.gov (United States)

    Liu, Shu-Jun; Xu, Heng-Heng; Wang, Wei-Qing; Li, Ni; Wang, Wei-Ping; Lu, Zhuang; Møller, Ian Max; Song, Song-Quan

    2016-06-01

    Seed germination is a critical phase in the plant life cycle, but the mechanism of seed germination is still poorly understood. In the present study, rice (Oryza sativa L. cv. Peiai 64S) seeds were sampled individually when they reached different germination stages, quiescent, germinated sensu stricto, germinated completely and seedling, and were used to study the changes in the embryo proteome. A total of 88 protein spots showed a significant change in abundance during germination in water, and the results showed an activation of metabolic processes. Cell division, cell wall synthesis, and secondary metabolism were activated at late seed germination and during preparation for subsequent seedling establishment. Cycloheximide (CHX) at 70μM inhibited seedling establishment without an apparent negative effect on seed germination, while CHX at 500μM completely blocked seed germination. We used this observation to identify the potentially important proteins involved in seed germination (coleoptile protrusion) and seedling establishment (coleoptile and radicle protrusion). Twenty-six protein spots, mainly associated with sugar/polysaccharide metabolism and energy production, showed a significant difference in abundance during seed germination. Forty-nine protein spots, mainly involved in cell wall biosynthesis, proteolysis as well as cell defense and rescue, were required for seedling establishment. The results help improve our understanding of the key events (proteins) involved in germination and seedling development.

  1. Production and development of eucalyptus seedlings in function of doses of phosphorus

    Directory of Open Access Journals (Sweden)

    José Henrique Tertulino Rocha

    2013-12-01

    Full Text Available This study evaluated the effect of phosphorus (P on the survival in the nursery and early development in the field of clonal Eucalyptus urophylla x Eucalyptus grandis seedlings. The experimental design was completely randomized with four treatments and five replicates of 30 plants per replicate. At the end of the cycle (90 days, 15 seedlings were used for determining the dry matter accumulation and nutrient concentration in the shoot. The rest was planted in the field to determine the percentage of survival and early development. The treatments consisted of four doses of P fertilization (0.0, 1.3, 2.6 and 5.2 mg plant-1. To obtain high quality seedlings in conditions similar to this experiment it is required doses of P in the range from 3.6 to 3.8 mg plant-1. Doses greater than 4 mg plant-1 affect the development and quality of eucalyptus seedlings. An adequate phosphorus fertilization of eucalyptus seedlings increase, by about 30%, the percentage of surviving seedlings in the field.

  2. Root architecture and hydraulic conductance in nutrient deprived Pistacia lentiscus L. seedlings.

    Science.gov (United States)

    Trubat, Roman; Cortina, Jordi; Vilagrosa, Alberto

    2012-12-01

    Plants respond to low nutrient availability by modifying root morphology and root system topology. Root responses to nitrogen (N) and phosphorus (P) limitation may affect plant capacity to withstand water stress. But studies on the effect of nutrient availability on plant ability to uptake and transport water are scarce. In this study, we assess the effect of nitrogen and phosphorus limitation on root morphology and root system topology in Pistacia lentiscus L seedlings, a common Mediterranean shrub, and relate these changes to hydraulic conductivity of the whole root system. Nitrogen and phosphorus deprivation had no effect on root biomass, but root systems were more branched in nutrient limited seedlings. Total root length was higher in seedlings subjected to phosphorus deprivation. Root hydraulic conductance decreased in nutrient-deprived seedlings, and was related to the number of root junctions but not to other architectural traits. Our study shows that changes in nutrient availability affect seedling water use by modifying root architecture. Changes in nutrient availability should be taken into account when evaluating seedling response to drought.

  3. Performance of Oak Seedlings Grown under Different Oust® XP Regimes

    Directory of Open Access Journals (Sweden)

    Andrew Self

    2014-06-01

    Full Text Available Herbaceous weed control (HWC is prescribed for growing season control of vegetative competition in hardwood afforestation attempts on former agricultural areas. Without HWC, planted seedlings often exhibit poor growth and survival. While currently employed HWC methods are proven, there is a substantial void in research comparing HWC treatments spanning multiple years. A total of 4,320 bare-root seedlings of three oak species were planted on three Mississippi sites. All sites were of comparable soils and received above average precipitation for the majority of the three-year study. Eight combinations of HWC and mechanical site preparation were utilized at each site, with 480 seedlings planted in each of the nine blocks, and a total of 1,440 seedlings per species planted across all sites. Treatments were installed on 3.1 m centers, with mechanical treatments as follows: control, subsoiling, bedding, and combination plowing. HWC treatments included one and two-year applications of Oust® XP. Treatments were applied over seedlings post-planting in 1.5 m bands, at a rate of 140.1 g product/hectare. Excepting one species, HWC dependent height or groundline diameter differences were not detected among mechanical treatments, species, HWC regime, or combinations thereof. No survival differences were observed among site preparation treatments or species. However, analysis detected a growing season/HWC treatment interaction for seedling survival.

  4. Hunting alters seedling functional trait composition in a Neotropical forest.

    Science.gov (United States)

    Kurten, Erin L; Wright, S Joseph; Carson, Walter P

    2015-07-01

    Defaunation alters trophic interactions between plants and vertebrates, whichmay disrupt trophic cascades, thereby favoring a subset of plant species and reducing diversity. If particular functional traits characterize the favored plant species,.then defaunation may alter community-wide patterns of functional trait composition. Changes in plant functional traits occurring with defaunation may help identify the species interactions affected by defaunation and the potential for other cascading effects of defaunation. We tested the hypotheses that defaunation would (1) disrupt seed dispersal, thereby favoring species whose dispersal agents are not affected (e.g., small birds, bats, and abiotic agents), (2) reduce seed predation, thereby favoring larger-seeded species, and (3) reduce herbivory, thereby favoring species with lower leaf mass per area (LMA), leaf toughness, and wood density. We examined how these six traits responded to vertebrate defaunation caused by hunters or by experimental exclosures among more than-30 000 woody seedlings in a lowland tropical moist forest. Exclosures reduced terrestrial frugivores, granivores, and herbivores, while hunters also reduced volant and arboreal frugivores and granivores. The comparison of exclosures and hunting allowed us to parse the impacts of arboreal and volant species (reduced by hunters only) and terrestrial species (reduced by both hunters and exclosures). The loss of terrestrial vertebrates alone had limited effects on plant trait composition. The additional loss of volant and arboreal vertebrates caused significant shifts in plant species composition towards communities with more species dispersed abiotically, including lianas and low wood-density tree species, and fewer species dispersed by large vertebrates. In contrast to previous studies, community seed mass did not decline significantly in hunted sites. Our exclosure results suggest this is because reducing seed predators disproportionately benefits large

  5. SHOOT AND ROOT EVALUATIONS ON SEEDLINGS FROM Coffea GENOTYPES

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    RAMOS LUIS CARLOS DA SILVA

    1997-01-01

    Full Text Available Roots and shoots from seedlings of 29 coffee genotypes were studied to better characterize the entries from the Coffea germplasm bank of the Instituto Agronômico (IAC, Campinas, State of São Paulo, Brasil. The varieties were seeded in a randomized complete block design with 6 replications and 10 plants per plot. The characters evaluated were: plant (PL, shoot (SL and root (RL length; total plant (PDM, shoot (SDM, root (RDM and lateral root (LRDM dry matter. A lateral root index (LRI and shoot root dry matter (SRDM = SDM/RDM and length ratios; (SRL = SL/RL were calculated. The dwarf varieties (Catuaí, Icatu-caturra, Vila Sarchi, San Ramon, Vila Lobos, São Bernardo presented higher LRDM and lower SDM than the normal size varieties such as Mundo Novo, Bourbon Vermelho, Arábica, Amarelo de Botucatu, Glaucia, etc. The varieties Macrodiscus, Icatu-caturra, Bourbon Amarelo, Vila Lobos and C. congensis showed higher root development related to shoot. The Arábica coffee standard variety showed intermediary root and shoot development. Genotypes of high yield background were higher in SL and SDM, while the dwarf types had only lower SL than the normal ones, but higher RL and dry matters. Seedlings from genotypes of known higher field drought tolerance had lower SL and RL, but higher RDM. Significant phenotypic and genotypic correlation coefficients were obtained, such the genotypes for PL and PDM (r = 0.64; P = 0.01, SL and SDM (r = 0.40; P = 0.05, SDM and LRDM (r = 0.52; P = 0.05, RDM and LRI (r = 0.68; P = 0.01, LRI and SRDM (r = 0.85; P = 0.01 and LRI and LRDM (r = 0.84; P = 0.01. High genotypic correlations suggest that selection directed to one character will directly affect the other. Conversely, low or non-significant correlations suggest independence of association, an indication that it would be possible to select two characteristics to diverse directions. Selection could be done towards different goals to change root and shoot measures

  6. Quality of Schizolobium parahyba seeds and seedlings from Rio Grande do Sul, Santa Catarina and Paraná states

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    Edicléia Aparecida Iensen Cherobini

    2010-09-01

    Full Text Available This research aimed to study the vigor and the quality of Schizolobium parahyba seeds from samples of three differentstates, Rio Grande do Sul (RS, Santa Catarina (SC and Paraná (PR and to evaluate the seedlings quality produced by these seeds.The seeds were submitted to evaluations of moisture content, germination, vigor and healthy. The seedlings quality was evaluated byhard seeds, dead seeds, emergence, seedling height, root length, collar diameter, fresh and dry weight of seedlings. On the seedsevaluations, the samples from SC and PR presented better results for first count of germination, dry matter and accelerate aging. Thefungi associated to the seeds were Aspergillus sp., Alternaria sp., Penicillium sp. and Trichoderma sp. About the seedlings evaluations,seeds from PR showed the bests results when the differences between tests were significant (emergence, root length and dry weight ofseedlings. Some of the labs variables had correlation with the seedlings variables.

  7. Experimental test for facilitation of seedling recruitment by the dominant bunchgrass in a fire-maintained savanna.

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    Gwenllian D Iacona

    Full Text Available Facilitative interactions between neighboring plants can influence community composition, especially in locations where environmental stress is a factor limiting competitive effects. The longleaf pine savanna of the southeastern United States is a threatened and diverse system where seedling recruitment success and understory species richness levels are regulated by the availability of moist microsites. We hypothesized that the dominant bunch grass species (Aristida stricta Michx. would facilitate moist seedling microsites through shading, but that the effect would depend on stress gradients. Here, we examined the environmental properties modified by the presence of wiregrass and tested the importance of increased shade as a potential facilitative mechanism promoting seedling recruitment across spatial and temporal stress gradients. We showed that environmental gradients, season, and experimental water manipulation influence seedling success. Environmental properties were modified by wiregrass proximity in a manner that could facilitate seedling success, but we showed that shade alone does not provide a facilitative benefit to seedlings in this system.

  8. Stress of Cl- is Stronger than That of Na+ on Glycine max Seedlings Under NaCl Stress

    Institute of Scientific and Technical Information of China (English)

    LUO Qing-yun; YU Bing-jun; LIU You-liang

    2002-01-01

    Seedlings of six Glycine max cultivars were used to compare Cl- with Na+ in stress effects onsoybean seedlings under NaCl stress. Results showed that stress of NaCl on G. max seedlings was mainlycaused by Cl- and not by Na+. After treatment with isoosmotic solutions of Cl- (without Na+ ) and Na+ (with-out Cl-) respectively, fresh weight and height of G. max seedlings growing in solution of Cl- were much morestressed than those in solution of Na+. And the roots and leaves electrolyte leakage were much more increasedunder stress of Cl- than those under stress of Na+. Salt tolerance of G. max seedlings was mainly contributedto Cl- withheld in roots of seedlings to decrease its content in leaves.

  9. There's no place like home: seedling mortality contributes to the habitat specialisation of tree species across Amazonia.

    Science.gov (United States)

    Fortunel, Claire; Paine, C E Timothy; Fine, Paul V A; Mesones, Italo; Goret, Jean-Yves; Burban, Benoit; Cazal, Jocelyn; Baraloto, Christopher

    2016-10-01

    Understanding the mechanisms generating species distributions remains a challenge, especially in hyperdiverse tropical forests. We evaluated the role of rainfall variation, soil gradients and herbivory on seedling mortality, and how variation in seedling performance along these gradients contributes to habitat specialisation. In a 4-year experiment, replicated at the two extremes of the Amazon basin, we reciprocally transplanted 4638 tree seedlings of 41 habitat-specialist species from seven phylogenetic lineages among the three most important forest habitats of lowland Amazonia. Rainfall variation, flooding and soil gradients strongly influenced seedling mortality, whereas herbivory had negligible impact. Seedling mortality varied strongly among habitats, consistent with predictions for habitat specialists in most lineages. This suggests that seedling performance is a primary determinant of the habitat associations of adult trees across Amazonia. It further suggests that tree diversity, currently mostly harboured in terra firme forests, may be strongly impacted by the predicted climate changes in Amazonia.

  10. Seedling diversity and spatially related regenaration dynamics in holly woodlands and surrounding habitats

    Directory of Open Access Journals (Sweden)

    S. Arrieta

    2001-06-01

    Full Text Available Spatial patterns of seedling distribution and diversity were analysed in small fragments of holly Ilex aquifolium L. woodlands and in their surrounding areas. Two sampling locations with similar structure were selected for this study: Oncala and Robregordo. They consist of nearly monospecific Ilex stands surrounded by grasslands with high scrub abundance.

    The seedling appearance of woody species was quantified from March to November 1998. Sampled areas were: 1 closed holly canopy; 2 open holly canopy or small forest gaps; 3 holly woodland edge; 4 surrounding grassland; 5 under isolated fleshy-fruited shrubs scattered over the grassland; 6 under dry-fruited shrubs and 7 the closest forest to the holly woodland. Additionally, a pine forest at a distance of 20 km from Oncala was sampled. In every area ten permanent 50 × 50 cm quadrats were fixed for monthly seedling control.

    The highest germination density occurs under the holly woodland, especially in closed canopy areas. Nevertheless, these closed woodlands neither maintain a great quantity of surviving seedlings nor a high diversity. Seedling density is considerable in canopy gaps, shrubs and forest edge, and these habitats have greater diversity values than understorey habitats. Fleshy-fruited shrubs maintain higher seedling densities and diversity than dry-fruited shrubs. Woody seedlings are rare over the grassland. The three non-holly forests studied have very similar seedling densities and diversity values, higher than those under closed-canopy holly.

    Regional differences are important for the numbers of seedlings surviving from previous years, which are scareer in Robregordo. However, little difference is observed in spatial patterns of seedling diversity between the two locations.

    We discuss a number of processes affecting seed rain density and differential mortality rates that could account for these spatial patterns, namely competition

  11. Two novel techniques to screen Abies seedlings for resistance to the balsam woolly adelgid, Adelges piceae.

    Science.gov (United States)

    Newton, Leslie; Frampton, John; Monahan, John; Goldfarb, Barry; Hain, Fred

    2011-01-01

    Since its introduction into the Southern Appalachians in the 1950s, the balsam woolly adelgid, Adelges piceae Ratzeburg (Hemiptera: Adelgidae), has devastated native populations of Fraser fir, Abies fraseri (Pursh) Poir. (Pinales: Pinaceae), and has become a major pest in Christmas tree plantations requiring expensive chemical treatments. Adelges piceae-resistant Fraser fir trees would lessen costs for the Christmas tree industry and assist in the restoration of native stands. Resistance screening is an important step in this process. Here, four studies directed toward the development of time- and cost-efficient techniques for screening are reported. In the first study, three methods to artificially infest seedlings of different ages were evaluated in a shade-covered greenhouse. Two-year-old seedlings had much lower infestation levels than 7 year-old seedlings. Placing infested bark at the base of the seedling was less effective than tying infested bark to the seedling or suspending infested bolts above the seedling. Although the two latter techniques resulted in similar densities on the seedlings, they each have positive and negative considerations. Attaching bark to uninfested trees is effective, but very time consuming. The suspended bolt method mimics natural infestation and is more economical than attaching bark, but care must be taken to ensure an even distribution of crawlers falling onto the seedlings. The second study focused on the density and distribution of crawlers falling from suspended bolts onto paper gridded into 7.6 × 7.6 cm cells. Crawler density in a 30 cm band under and to each side of the suspended bolt ranged from 400 to over 3000 crawlers per cell (1 to 55 crawlers per cm²). In the third study, excised branches from 4 year-old A. fraseri and A. vetchii seedlings were artificially infested with A. piceae to determine whether this technique may be useful for early resistance screening. The excised A. fraseri branches supported complete

  12. Seedling establishment at the alpine tree line - Can there be too much winter protection?

    Science.gov (United States)

    Lett, S.; Wardle, D.; Nilsson, M. C.; Dorrepaal, E.

    2014-12-01

    Alpine and arctic tree line expansion relies on tree seedling survival above the tree line, where the environment is harsh and protection by snow during winter is essential. Above the tree line, bryophytes are dominant; they may act as thermal insulators but their insulating ability differs between species. Apart from these positive effects, both snow and bryophytes may have negative effects on seedlings via shortening of the growing season or competition, respectively. Snow depth and duration are expected to change due to climate change, leading in some places to more snow and in others to less. What is the role of bryophytes insulating properties for seedling establishment under changing winter conditions at the alpine tree line? We hypothesized that protecting effects of snow and bryophytes would be more important for seedling survival in harsh climate (high elevation) than in milder climate (low elevation) (interactions: bryophyte*elevation and snow*elevation) and that negative effects of less snow would be ameliorated by well-insulating bryophytes (interaction: bryophyte*snow). To test this, we transplanted cores of three bryophyte species of differing insulation capacity and bare soil (control) from the subarctic tree line (~600m asl.) to 700 and 350 m asl. We transplanted 10 seedlings of two common tree line tree species (Betula pubescens and Pinus sylvestris) into each core in late summer. Cores were subjected to one of three snow treatments: autumn and spring snow removal or addition, or no manipulation. After the winter we scored seedling survival. The snow treatments had different effects at the two elevations (elevation* snow: Pbryophytes did not (elevation*bryophyte: n.s). In the harsh climate, snow addition generally enhanced seedling survival. In contrast, at the milder climate site, snow addition only increased survival in the bare soil treatment but decreased survival of seedlings in the bryophyte cores (bryophyte*snow: P=0.053). Our data show that

  13. Identification of MiRNAs Affecting the Establishment of Brassica Alboglabra Seedling

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    Rongfang Guo

    2016-11-01

    Full Text Available MicroRNAs (miRNAs are important for plant development including seed formation, dormancy, and germination, as well as seedling establishment. The Brassica vegetable seedling establishment stage influences the development of high quality seedlings, but also affects the nutrient content of sprouts. Chinese kale (Brassica alboglabra seedlings at different growth stages were used to construct two small-RNA (sRNA libraries. We comprehensively analyzed the miRNAs in 2- and 9-day-old seedlings. An average of 11,722,490 clean reads were generated after removing low-quality reads and adapter contaminants. The results revealed that 37.65% and 26.69% of the sRNAs in 2- and 9-day-old seedlings, respectively, were 24 nt long. In total, 254 known mature miRNA sequences from 228 miRNA families and 343 novel miRNAs were identified. Of these miRNAs, 224 were differentially expressed between the two analyzed libraries. The most abundant miRNAs identified by sequence homology were miR156, miR167, and miR157, each with more than 100,000 sequenced reads. Compared with the expression levels in 2-day-old seedlings, MiR8154 and miR390 were the most up- and down-regulated miRNAs respectively in 9-day-old seedlings. Gene ontology enrichment analysis of the differentially expressed-miRNA target genes affecting biological processes revealed that most genes were in the regulation of transcription category. Additionally, the expression patterns of some miRNAs and target genes were validated by quantitative real-time polymerase chain reaction. We determined that development-associated miRNAs (e.g., bal-miR156/157/159/166/167/172/396, were highly-expressed during seedling-establishment stage, as were stress-related (bal-miR408 and metabolism-related (bal-miR826 miRNAs. Combined with the low level of targets SPL9 and AP2, it was concluded that miR156-SPL9 and miR172-AP modules play key roles during the B. alboglabra seedling establishment stage.

  14. Inheritance of autumn frost hardiness in Pinus sylvestris L. seedlings.

    Science.gov (United States)

    Norell, L; Eriksson, G; Ekberg, I; Dormling, I

    1986-07-01

    Inheritance of frost hardiness was analysed making use of a 12×12 incomplete factorial mating design. Owing to space limitations only 59 families could be tested in four experiments. To link the four experiments, some families were common to two or more experiments. The seedlings were grown in climate chambers under conditions inducing autumn hardening. The plants were exposed to a freezing temperature of -10 °C for three hours at night lengths of 11-13 h. A statistical model was developed for analyses of variance of our data. The genetic variation and the variation due to the cultivation regimes during autumn hardening were of the same magnitude. The additive effects were the most important ones for induction of frost damage. No interaction following long-distance crossing was noted. Mixed model equations were used for ranking of the parents. The results obtained support a polygenic inheritance of frost hardiness. The large within-population variation offers good opportunities for hardiness breeding.

  15. Dormancy overcome and seedling quality of pecan in nursery

    Directory of Open Access Journals (Sweden)

    Tales Poletto

    Full Text Available ABSTRACT: This study evaluated the efficiency of methods to overcome seed dormancy in different storage periods in the production of pecan seedlings. Seeds were submitted to the following treatments: T1, T4 and T7 - control treatments (seeds with no treatment, stored at room temperature for 30, 60 and 90 days, respectively, T2, T5 and T8 - stratification (seeds were distributed in boxes with wet sand maintained at a temperature of 4°C for 30, 60 and 90 days, respectively, T3, T6 and T9 - scarification + stratification (seeds scarified with sandpaper n.80 and stratified by 30, 60 and 90 days, respectively, in completely random experimental design. Plant height, stem diameter, number of leaves, full emergence and emergence speed index (ESI were evaluated after 14 weeks of sowing. The best development of pecan 'plants, their emergence, and ESI were observed in the stratification treatment for 90 day as well as in the scarification + stratification treatment for 90 day. Storing seeds in uncontrolled environment reduced their viability.

  16. Effect of spaceflight on isoflavonoid accumulation in etiolated soybean seedlings

    Science.gov (United States)

    Levine, L. H.; Levine, H. G.; Stryjewski, E. C.; Prima, V.; Piastuch, W. C.; Sager, J. S. (Principal Investigator)

    2001-01-01

    In order to explore the potential impact of microgravity on flavonoid biosynthesis, we examined isoflavonoid levels in soybean (Glycine max) tissues generated under both spaceflight and clinorotation conditions. A 6-day Space Shuttle-based microgravity exposure resulted in enhanced accumulation of isoflavone glycosides (daidzin, 6"-O-malonyl-7-O-glucosyl daidzein, genistin, 6"-O-malonyl-7-O-glucosyl genistein) in hypocotyl and root tissues, but reduced levels in cotyledons (relative to 1g controls on Earth). Soybean seedlings grown on a horizontally rotating clinostat for 3, 4 and 5 days exhibited (relative to a vertical clinorotation control) an isoflavonoid accumulation pattern similar to the space-grown tissues. Elevated isoflavonoid levels attributable to the clinorotation treatment were transient, with the greatest increase observed in the three-day-treated tissues and smaller increases in the four- and five-day-treated tissues. Differences between stresses presented by spaceflight and clinorotation and the resulting biochemical adaptations are discussed, as is whether the increase in isoflavonoid concentrations were due to differential rates of development under the "gravity" treatments employed. Results suggest that spaceflight exposure does not impair isoflavonoid accumulation in developing soybean tissues and that isoflavonoids respond positively to microgravity as a biochemical strategy of adaptation.

  17. Light Regulation of Gibberellins Metabolism in Seedling Development

    Institute of Scientific and Technical Information of China (English)

    Xiao-Ying Zhao; Xu-Hong Yu; Xuan-Ming Liu; Chen-Tao Lin

    2007-01-01

    Light affects many aspects of plant development, including seed germination, stem elongation, and floral initiation. How photoreceptors control photomorphogenic processes is not yet fully understood. Because phytohormones are chemical regulators of plant development, it may not be surprising that light affects,directly or indirectly, cellular levels and signaling processes of various phytohormones, such as auxin,gibberellins (GA), cytokinin, ethylene, abscisic acid (ABA), and brassinosteroids (BR). Among those phytohormones, light regulation of GA metabolism has probably attracted more attention among photobiologists and it is arguably the most extensively studied plant hormone at present with respect to its role in photomorphogenesis. It has become increasingly clear that phytochromes and cryptochromes are the major photoreceptors mediating light regulation of GA homeostasis. This short article attempts to examine some recent developments in our understanding of how light and photoreceptors regulate GA biosynthesis and catabolism during seedling development. It is not our intention to carry out a comprehensive review of the field, and readers are referred to recent review articles for a more complete view of this area of study (Kamiya and Garcia-Martinez 1999; Hedden and Phillips 2000; Garcia-Martinez and Gil 2001; Olszewski et al. 2002; Halliday and Fankhauser 2003; Sun and Gubler 2004).

  18. Inhibition of chickpea seedling copper amine oxidases by tetraethylenepentamine

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    Sona Talaei

    2012-01-01

    Full Text Available Copper amine oxidases are important enzymes, which contribute to the regulation of mono- and polyamine levels. Each monomer contains one Cu(II ion and 2,4,5-trihydroxyphenylalanine (TPQ as cofactors. They catalyze the oxidative deamination of primary amines to aldehydes with a ping-pong mechanism consisting of a transamination. The mechanism is followed by the transfer of two electrons to molecular oxygen which is reduced to hydrogen peroxide. Inhibitors are important tools in the study of catalytic properties of copper amine oxidases and they also have a wide application in physiological research. In this study, purification of the chickpea seedling amine oxidase, was done via salting out by ammonium sulfate and dialysis, followed by DEAE-cellulose column chromatography. By using the Lineweaver - Burk plot, the Km and Vm of the enzyme were found to be 3.3 mM and 0.95 mmol/min/mg, respectively. In this study, the interaction of chickpea diamino oxidase with tetraethylene- pentamine was studied. Analysis of kinetic data indicated that tetraethylenepentamine (with Ki=0.1 mM inhibits the enzyme by linear mixed inhibitory effect.

  19. Heavy-metal nutrition and iron chlorosis of citrus seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.F.; Specht, A.W.

    1953-01-01

    Studies were made on the responses to differential supplies of copper, zinc, manganese, and iron shown by sweet orange and mandarin seedlings grown in vermiculite and solution cultures with the pH maintained near 4. The first three metallic ions were all found to interfere with Fe metabolism in such a way as to induce chlorosis under certain conditions. Relatively low concentrations of these elements also were toxic to roots. Copper appeared to be about 50 times as toxic as Mn and 12 to 15 times as toxic as Zn. Strongly chelated Fe prevented the development of chlorosis. It did not, however, prevent Cu toxicity in roots. It appeared to reduce slightly Zn toxicity in roots and to alleviate greatly toxicity due to Mn. Cu accumulates in roots, even to the point of toxicity, without being transported to the upper parts of the plants in increased amounts. Both Zn and Mn show marked accumulation in the roots as well as substantial distribution within the plant when these elements are increased in the nutrient solution. 12 references, 4 tables.

  20. Automorphogenesis and gravitropism of plant seedlings grown under microgravity conditions.

    Science.gov (United States)

    Hoson, T; Saiki, M; Kamisaka, S; Yamashita, M

    2001-01-01

    Plant seedlings exhibit automorphogenesis on clinostats. The occurrence of automorphogenesis was confirmed under microgravity in Space Shuttle STS-95 flight. Rice coleoptiles showed an inclination toward the caryopsis in the basal region and a spontaneous curvature in the same adaxial direction in the elongating region both on a three-dimensional (3-D) clinostat and in space. Both rice roots and Arabidopsis hypocotyls also showed a similar morphology in space and on the 3-D clinostat. In rice coleoptiles, the mechanisms inducing such an automorphic curvature were studied. The faster-expanding convex side of rice coleoptiles showed a higher extensibility of the cell wall than the opposite side. Also, in the convex side, the cell wall thickness was smaller, the turnover of the matrix polysaccharides was more active, and the microtubules oriented more transversely than the concave side, and these differences appear to be causes of the curvature. When rice coleoptiles grown on the 3-D clinostat were placed horizontally, the gravitropic curvature was delayed as compared with control coleoptiles. In clinostatted coleoptiles, the corresponding suppression of the amyloplast development was also observed. Similar results were obtained in Arabidopsis hypocotyls. Thus, the induction of automorphogenesis and a concomitant decrease in graviresponsiveness occurred in plant shoots grown under microgravity conditions.

  1. Cell wall proteins in seedling cotyledons of Prosopis chilensis.

    Science.gov (United States)

    Rodríguez, J G; Cardemil, L

    1994-01-01

    Four cell wall proteins of cotyledons of Prosopis chilensis seedlings were characterized by PAGE and Western analyses using a polyclonal antibody, generated against soybean seed coat extensin. These proteins had M(r)s of 180,000, 126,000, 107,000 and 63,000, as determined by SDS-PAGE. The proteins exhibited a fluorescent positive reaction with dansylhydrazine suggesting that they are glycoproteins; they did not show peroxidase activity. The cell wall proteins were also characterized by their amino acid composition and by their amino-terminal sequence. These analyses revealed that there are two groups of related cell wall proteins in the cotyledons. The first group comprises the proteins of M(r)s 180,000, 126,000, 107,000 which are rich in glutamic acid/glutamine and aspartic acid/asparagine and they have almost identical NH2-terminal sequences. The second group comprises the M(r) 63,000 protein which is rich in proline, glycine, valine and tyrosine, with an NH2-terminal sequence which was very similar to that of soybean proline-rich proteins.

  2. Acinetobacter plantarum sp. nov. isolated from wheat seedlings plant.

    Science.gov (United States)

    Du, Juan; Singh, Hina; Yu, Hongshan; Jin, Feng-Xie; Yi, Tae-Hoo

    2016-07-01

    Strain THG-SQM11(T), a Gram-negative, aerobic, non-motile, coccus-shaped bacterium, was isolated from wheat seedlings plant in P. R. China. Strain THG-SQM11(T) was closely related to members of the genus Acinetobacter and showed the highest 16S rRNA sequence similarities with Acinetobacter junii (97.9 %) and Acinetobacter kookii (96.1 %). DNA-DNA hybridization showed 41.3 ± 2.4 % DNA reassociation with A. junii KCTC 12416(T). Chemotaxonomic data revealed that strain THG-SQM11(T) possesses ubiquinone-9 as the predominant respiratory quinone, C18:1 ω9c, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), and C16:0 as the major fatty acids. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine. The DNA G+C content was 41.7 mol %. These data, together with phenotypic characterization, suggest that the isolate represents a novel species, for which the name Acinetobacter plantarum sp. nov. is proposed, with THG-SQM11(T) as the type strain (=CCTCC AB 2015123(T) =KCTC 42611(T)).

  3. Sorghum Seedling Drought Response: in Search of Tolerant Genotypes

    Directory of Open Access Journals (Sweden)

    Irawati Chanaigo

    2017-06-01

    Full Text Available Drought stress is a major factor contributing disease susceptibility and yield loss in agricultural crops. The experiment reported here was aimed at studying the germination and early growth of ten sorghum (Sorghum bicolor L. Moench genotypes in 0 or 20% (w/v polyethylene glycol (PEG 6000 solution as a model to mimic drought stress. The experiment was carried out at the Laboratory of Seed Technology and a glass house of Faculty of Agriculture, Andalas University Padang from March to April 2015. A two-way factorial experiment in a completely randomised design with three replicates was assigned. Data were analysed with analysis of variance and mean comparisons of Duncan’s New Multiple Range Test at 5% level. When only PEG was found to be significant then mean comparisons was calculated according to t-Dunnet test. Sorghum seeds were germinated on two layers of Whatmann paper in Petri dishs either in 0% or 20% PEG for seven days prior to transfer into Hoagland solution containing 0 or 20% PEG with layer of paraffin wax for 21 days in a glass house. Results indicated that 20% PEG solution reduced seedling dry weight and the length or roots protruding from the paraffin wax layer in some genotypes. Sorghum genotype No. 5 was more tolerant to drought stress in their early growth followed by genotypes Samurai 2, Samurai Batan, and Pahat Batan. In contrast, genotypes Advanta and No. 44 were found to be the most susceptible.

  4. Prosopis pubescens (screw bean mesquite) seedlings are hyperaccumulators of copper.

    Science.gov (United States)

    Zappala, Marian N; Ellzey, Joanne T; Bader, Julia; Peralta-Videa, Jose R; Gardea-Torresdey, Jorge

    2013-08-01

    Due to health reasons, toxic metals must be removed from soils contaminated by mine tailings and smelter activities. The phytoremediation potential of Prosopis pubescens (screw bean mesquite) was examined by use of inductively-coupled plasma optical emission spectroscopy. Transmission electron microscopy was used to observe ultrastructural changes of parenchymal cells of leaves in the presence of copper. Elemental analysis was used to localize copper within leaves. A 600-ppm copper sulfate exposure to seedlings for 24 days resulted in 31,000 ppm copper in roots, 17,000 ppm in stems, 11,000 in cotyledons and 20 ppm in the true leaves. For a plant to be considered a hyperaccumulator, the plant must accumulate a leaf-to-root ratio <1. Screw bean mesquite exposed to copper had a leaf-to-root ratio of 0.355 when cotyledons were included. We showed that P. pubescens grown in soil is a hyperaccumulator of copper. We recommend that this plant should be field tested.

  5. Light affects the chloroplast ultrastructure and post-storage photosynthetic performance of watermelon (Citrullus lanatus) plug seedlings.

    Science.gov (United States)

    Duan, Qingqing; Jiang, Wu; Ding, Ming; Lin, Ye; Huang, Danfeng

    2014-01-01

    Watermelon [Citrullus lanatus (Thunb.) Matsum. and Nakai] plug seedlings were stored at 15°C in the light at a photosynthetic photon flux density of 15 µmol·m(-2)·s(-1) or in darkness for 6 days, to evaluate their chloroplast ultrastructure, and associated photosynthetic characteristics. Storage in the dark caused swelling, disordered granal arrangement, and starch grain disappearance in the chloroplasts. In contrast, the chloroplasts stored in the light were relatively normal. As a result, the light-stored seedlings had a significantly higher chlorophyll content, Fv/Fm, and Pn than did dark-stored seedlings. Regardless of whether the seedlings were stored in light or darkness, the Gs and Ls of the seedlings significantly decreased, while the Ci obviously increased when the Pn decreased after 6 days of storage. This result suggests that the decreased Pn is not solely a stomatal effect, as the effects on the chloroplasts contributed to this photosynthetic inhibition. Six days after transplanting, seedlings that were stored in the light or darkness for 2 or 4 days showed complete recovery of chloroplast ultrastructure, chlorophyll content, Fv/Fm, Gs and Pn. When the storage period increased to 6 days, the dark-stored seedlings had a significantly lower Fv/Fm and Pn than the light-stored and control seedlings 6 days after transplanting, which was mainly ascribed to incomplete recovery of chloroplast ultrastructure. Furthermore, the light-stored seedlings exhibited a significantly higher shoot dry weight during storage and a higher percentage dry weight increase after transplanting than the dark-stored seedlings. These effects were enhanced by prolonged storage (4 to 6 days). This study demonstrated that dim light during storage is beneficial for maintaining chloroplast ultrastructure as well as photosynthetic efficiency in watermelon seedlings, thus contributing to the rapid recovery of post-storage photosynthetic performance, which ensures the transplant quality

  6. Effect of benfluralin on Pinus pinea seedlings mycorrhized with Pisolithus tinctorius and Suillus bellinii – Study of plant antioxidant response

    OpenAIRE

    Franco, A. R.; Pereira, Sofia I. A.; Castro, Pauia M. L.

    2015-01-01

    In this study, Pinus pinea seedlings mycorrhized with selected ectomycorrhizal fungi (ECMF), Pisolithus tinctorius and Suillus bellinii, were exposed to the herbicide benfluralin. Non-mycorrhized P. pinea seedlings and seedlings mycorrhized with ECMF were transferred to benfluralin-spiked soils at levels of 0.165, 1.65 and 16.5 mg kg 1. Plant growth and the fungal role on plant antioxidant response were assessed. In the presence of benfluralin, higher plant growth was observed in ...

  7. Ecophysiological assessment of western hemlock seedlings for coastal regeneration programs in British Columbia. FRDA report No. 183

    Energy Technology Data Exchange (ETDEWEB)

    Grossnickle, S.C.; Arnott, J.T.; Major, J.E.

    1992-01-01

    Understanding how stocktypes respond physiologically and morphologically to reforestation site conditions is of paramount importance to achieving successful reforestation. Few studies have examined the relationship between seedling stocktypes and their subsequent physiological and morphological responses to field site environmental conditions. This project documented the forest regeneration performance of western hemlock seedlings produced from a series of dormancy induced treatments achieved by characterizing seedling quality just prior to field planting and linking this assessment to physiological response and morphological development after planting.

  8. Effect of co-inoculations of native PGPR with nitrogen fixing bacteria on seedling traits in Prosopis cineraria.

    Science.gov (United States)

    Singh, S K; Pancholy, Anjly; Jindal, S K; Pathak, Rakesh

    2014-09-01

    Prosopis cineraria significantly contribute to sand dune stabilization, soil fertility rejuvenation and is an integral component of agro-forestry systems in arid regions of India. Effect of different rhizobacterial seed treatments on seed germination and seedling traits in two genotypes of P. cineraria (HPY-1) and (FG-1) were tested. Observations on seed germination (%) and seedling traits viz., root length (cm), shoot length (cm), seedling weight (g) and seedling length of different treatments were recorded. Whereas, germination index (GI), seedling vigour index (SVI) and root/shoot length ratio were derived from the observed data. The scarification treatment with sulphuric acid for 10 minutes substantially enhanced germination from < 20% to 80-82% in control treatments. Treatments with co-inoculations of Bacillus licheniformis and Sinorhizobium kostiense or S. saheli supported the maximum seed germination and seedling growth and vigour. The maximum germination per cent (92.5%), seedling length (10.94 cm), seedling vigour index (10.12) and germination index (7.97) were recorded with treatment (V2T6) wherein seeds of high pod yielding genotype were co-inoculated with Bacillus licheniformis and S. kostiense. The higher positive correlations of seedling length v/s shoot length followed by SVI v/s seedling length, SVI v/s root length and seedling length v/s root length is a fair indicative of inter dependency of these characteristics. Higher R2 values of root length v/s shoot length followed by that of SVI v/s GI indicates that a regression line fits the data well and future outcomes of observed seedling traits are likely to be predicted by the model.

  9. A Mutation in Arabidopsis SEEDLING PLASTID DEVELOPMENT1 Affects Plastid Differentiation in Embryo-Derived Tissues during Seedling Growth1[W][OA

    Science.gov (United States)

    Ruppel, Nicholas J.; Logsdon, Charles A.; Whippo, Craig W.; Inoue, Kentaro; Hangarter, Roger P.

    2011-01-01

    Oilseed plants like Arabidopsis (Arabidopsis thaliana) develop green photosynthetically active embryos. Upon seed maturation, the embryonic chloroplasts degenerate into a highly reduced plastid type called the eoplast. Upon germination, eoplasts redifferentiate into chloroplasts and other plastid types. Here, we describe seedling plastid development1 (spd1), an Arabidopsis seedling albino mutant capable of producing normal green vegetative tissues. Mutant seedlings also display defects in etioplast and amyloplast development. Precocious germination of spd1 embryos showed that the albino seedling phenotype of spd1 was dependent on the passage of developing embryos through the degreening and dehydration stages of seed maturation, suggesting that SPD1 is critical during eoplast development or early stages of eoplast redifferentiation. The SPD1 gene was found to encode a protein containing a putative chloroplast-targeting sequence in its amino terminus and also domains common to P-loop ATPases. Chloroplast localization of the SPD1 protein was confirmed by targeting assays in vivo and in vitro. Although the exact function of SPD1 remains to be defined, our findings reveal aspects of plastid development unique to embryo-derived cells. PMID:21045120

  10. The effects of methyl bromide alternatives on soil and seedling microbial populations, weeds, and seedling morphology in Oregon and Washington forest tree nurseries

    Science.gov (United States)

    Six fumigant treatments were evaluated at two forest tree nurseries in Oregon and one forest tree nursery in Washington for their effects on soil microbial populations, weeds, and seedling morphology during a 2-year study. Fusarium commune, F. oxysporum, Gibberella fujikuroi complex, P. irregulare,...

  11. Lack of influence of low temperature, light and growth substances on phytochrome resynthesis in coleoptiles of irradiated oat seedlings

    Directory of Open Access Journals (Sweden)

    Jan Kopcewicz

    2014-02-01

    Full Text Available The photoconversion of phytochrome PR into the PFR form causes at the same time the destruction of the initial large fraction of phytochrome found in the coleoptiles of etiolated oat seedlings. Factors such as low temperature, light of different wavelengths or growth substances are not capable of preventing the progressive destruction and restore the synthesis of phytochrome. Thus an abnormally high level of phytochrome is found only in etiolated seedlings. Such seedlings, on the other hand, are characterized by a very high rate of elongation growth. The role of phytochrome in the control of deetiolation of seedlings is discussed.

  12. Involvement of gibberellins in expression of a cysteine proteinase (SH-EP) in cotyledons of Vigna mungo seedlings.

    Science.gov (United States)

    Taneyama, M; Okamoto, T; Yamane, H; Minamikawa, T

    2001-11-01

    The expression of a papain-type proteinase, designated SH-EP, in cotyledons of Vigna mungo seedlings has been shown to require some factors in the embryonic axes. Gibberellin A1 (GA(1)) and GA(20) were identified by GC-MS in embryonic axes of V. mungo seedlings. The level of accumulation of SH-EP in cotyledons of V. mungo seedlings was greatly reduced by treatment of the seeds with uniconazole-P, an inhibitor for GA biosynthesis. The reduced level of accumulation of SH-EP in cotyledons by uniconazole-P was recovered by exogenous application of GA(1) and GA(20) to the seedlings.

  13. The effect of natural biostimulators and slow-disintegrating fertilizers on the quality of rosemary seedlings (Rosmarinus officinalis L.

    Directory of Open Access Journals (Sweden)

    Jelačić Slavica

    2007-01-01

    Full Text Available In the present work the effect of natural biostimulators and different doses of slow disintegrating fertilizer on the quality of rosemary seedlings was studied. Rosemary seedlings were produced in containers, according to the 'speedling system'. During the production of seedlings natural biostimulators Megafol and Viva and microbiological fertilizer Slavol were added. The applied biostimulators made a significant effect on the quality of rosemary seedlings. Different doses of the slow disintegrating fertilizer Scotts (Osmocote Extact were applied (0, 1, 2, 3 and 4 g/l, which also produced a significant influence.

  14. Root growth, secondary root formation and root gravitropism in carotenoid-deficient seedlings of Zea mays L

    Science.gov (United States)

    Ng, Y. K.; Moore, R.

    1985-01-01

    The effect of ABA on root growth, secondary-root formation and root gravitropism in seedlings of Zea mays was investigated by using Fluridone-treated seedlings and a viviparous mutant, both of which lack carotenoids and ABA. Primary roots of seedlings grown in the presence of Fluridone grew significantly slower than those of control (i.e. untreated) roots. Elongation of Fluridone-treated roots was inhibited significantly by the exogenous application of 1 mM ABA. Exogenous application of 1 micromole and 1 nmole ABA had either no effect or only a slight stimulatory effect on root elongation, depending on the method of application. The absence of ABA in Fluridone-treated plants was not an important factor in secondary-root formation in seedlings less than 9-10 d old. However, ABA may suppress secondary-root formation in older seedlings, since 11-d-old control seedlings had significantly fewer secondary roots than Fluridone-treated seedlings. Roots of Fluridone-treated and control seedlings were graviresponsive. Similar data were obtained for vp-9 mutants of Z. mays, which are phenotypically identical to Fluridone-treated seedlings. These results indicate that ABA is necessary for neither secondary-root formation nor for positive gravitropism by primary roots.

  15. Allocation strategies of savanna and forest tree seedlings in response to fire and shading: outcomes of a field experiment

    Science.gov (United States)

    Gignoux, Jacques; Konaté, Souleymane; Lahoreau, Gaëlle; Le Roux, Xavier; Simioni, Guillaume

    2016-12-01

    The forest-savanna ecotone may be very sharp in fire-prone areas. Fire and competition for light play key roles in its maintenance, as forest and savanna tree seedlings are quickly excluded from the other ecosystem. We hypothesized a tradeoff between seedling traits linked to fire resistance and to competition for light to explain these exclusions. We compared growth- and survival-related traits of two savanna and two forest species in response to shading and fire in a field experiment. To interpret the results, we decomposed our broad hypothesis into elementary tradeoffs linked to three constraints, biomass allocation, plant architecture, and shade tolerance, that characterize both savanna and adjacent forest ecosystems. All seedlings reached similar biomasses, but forest seedlings grew taller. Savanna seedlings better survived fire after topkill and required ten times less biomass than forest seedlings to survive. Finally, only savanna seedlings responded to shading. Although results were consistent with the classification of our species as mostly adapted to shade tolerance, competition for light in the open, and fire tolerance, they raised new questions: how could savanna seedlings survive better with a 10-times lower biomass than forest seedlings? Is their shade intolerance sufficient to exclude them from forest understory?

  16. Effect of different doses of slow-disintegrating fertilizer on the quality of impatiens' seedlings (Impatiens walleriana L.

    Directory of Open Access Journals (Sweden)

    Vujošević Ana

    2008-01-01

    Full Text Available The paper studies the effect of applying different doses of slow disintegrating fertilizer 'Scotts' ( Osmocote Exact of the formulation 15:9:9:MgO + Me to the quality of impatiens seedlings. The impatiens' seedlings were produced in poly-styrene containers ( speedling system and poly-propylene pots ( pot system . During the seedlings' production, the fertilizer was added in different doses (0, 1, 2, 3, and 4g/l . The obtained results have shown that the dose of 4 g/l of fertilizer significantly influences on the qualitative features of the impatiens' seedlings.

  17. Sensitivity of cold acclimation to elevated autumn temperature in field-grown Pinus strobus seedlings

    Directory of Open Access Journals (Sweden)

    Christine Yao-Yun Chang

    2015-03-01

    Full Text Available Climate change will increase autumn air temperature, while photoperiod decrease will remain unaffected. We assessed the effect of increased autumn air temperature on timing and development of cold acclimation and freezing resistance in Eastern white pine (EWP, Pinus strobus under field conditions. For this purpose we simulated projected warmer temperatures for southern Ontario in a Temperature Free-Air-Controlled Enhancement (T-FACE experiment and exposed EWP seedlings to ambient (Control or elevated temperature (ET, +1.5°C/+3°C during day/night. Photosynthetic gas exchange, chlorophyll fluorescence, photoprotective pigments, leaf non-structural carbohydrates (NSC, and cold hardiness were assessed over two consecutive autumns. Nighttime temperature below 10°C and photoperiod below 12h initiated downregulation of assimilation in both treatments. When temperature further decreased to 0°C and photoperiod became shorter than 10h, downregulation of the light reactions and upregulation of photoprotective mechanisms occurred in both treatments. While ET seedlings did not delay the timing of the downregulation of assimilation, stomatal conductance in ET seedlings was decreased by 20-30% between August and early October. In both treatments leaf NSC composition changed considerably during autumn but differences between Control and ET seedlings were not significant. Similarly, development of freezing resistance was induced by exposure to low temperature during autumn, but the timing was not delayed in ET seedlings compared to Control seedlings. Our results indicate that EWP is most sensitive to temperature changes during October and November when downregulation of photosynthesis , enhancement of photoprotection, synthesis of cold-associated NSCs and development of freezing resistance occur. However, we also conclude that the timing of the development of freezing resistance in EWP seedlings is not affected by moderate temperature increases used in our

  18. Gibberellin is required for the formation of tension wood and stem gravitropism in Acacia mangium seedlings.

    Science.gov (United States)

    Nugroho, Widyanto Dwi; Yamagishi, Yusuke; Nakaba, Satoshi; Fukuhara, Shiori; Begum, Shahanara; Marsoem, Sri Nugroho; Ko, Jae-Heung; Jin, Hyun-O; Funada, Ryo

    2012-09-01

    Angiosperm trees generally form tension wood on the upper sides of leaning stems. The formation of tension wood is an important response to gravitational stimulus. Gibberellin appears to be involved in the differentiation of secondary xylem, but it remains unclear whether gibberellin plays a key role in the formation of tension wood and plant gravitropism. Therefore, a study was designed to investigate the effects of gibberellin and of inhibitors of the synthesis of gibberellin, namely paclobutrazole and uniconazole-P, on the formation of tension wood and negative stem gravitropism in Acacia mangium seedlings. Gibberellic acid (GA(3)), paclobutrazole and uniconazole-P were applied to seedlings via the soil in which they were growing. Distilled water was applied similarly as a control. Three days after such treatment, seedlings were tilted at an angle of 45° from the vertical, and samples of stems were collected for analysis 2 weeks, 2 months and 6 months after tilting. The effects of treatments on the stem recovery degree (Rº) were analysed as an index of the negative gravitropism of seedlings, together the width of the region of tension wood in the upper part of inclined stems. It was found that GA(3) stimulated the negative gravitropism of tilted seedling stems of A. mangium, while paclobutrazole and uniconazole-P inhibited recovery to vertical growth. Moreover, GA(3) stimulated the formation of tension wood in tilted A. mangium seedlings, while paclobutrazole and uniconazole-P strongly suppressed the formation of tension wood, as assessed 2 weeks after tilting. The results suggest that gibberellin plays an important role at the initial stages of formation of tension wood and in stem gravitropism in A. mangium seedlings in response to a gravitational stimulus.

  19. Seedling establishment in a masting desert shrub parallels the pattern for forest trees

    Science.gov (United States)

    Meyer, Susan E.; Pendleton, Burton K.

    2015-05-01

    The masting phenomenon along with its accompanying suite of seedling adaptive traits has been well studied in forest trees but has rarely been examined in desert shrubs. Blackbrush (Coleogyne ramosissima) is a regionally dominant North American desert shrub whose seeds are produced in mast events and scatter-hoarded by rodents. We followed the fate of seedlings in intact stands vs. small-scale disturbances at four contrasting sites for nine growing seasons following emergence after a mast year. The primary cause of first-year mortality was post-emergence cache excavation and seedling predation, with contrasting impacts at sites with different heteromyid rodent seed predators. Long-term establishment patterns were strongly affected by rodent activity in the weeks following emergence. Survivorship curves generally showed decreased mortality risk with age but differed among sites even after the first year. There were no detectable effects of inter-annual precipitation variability or site climatic differences on survival. Intraspecific competition from conspecific adults had strong impacts on survival and growth, both of which were higher on small-scale disturbances, but similar in openings and under shrub crowns in intact stands. This suggests that adult plants preempted soil resources in the interspaces. Aside from effects on seedling predation, there was little evidence for facilitation or interference beneath adult plant crowns. Plants in intact stands were still small and clearly juvenile after nine years, showing that blackbrush forms cohorts of suppressed plants similar to the seedling banks of closed forests. Seedling banks function in the absence of a persistent seed bank in replacement after adult plant death (gap formation), which is temporally uncoupled from masting and associated recruitment events. This study demonstrates that the seedling establishment syndrome associated with masting has evolved in desert shrublands as well as in forests.

  20. Hydrogen sulphide improves adaptation of Zea mays seedlings to iron deficiency.

    Science.gov (United States)

    Chen, Juan; Wu, Fei-Hua; Shang, Yu-Ting; Wang, Wen-Hua; Hu, Wen-Jun; Simon, Martin; Liu, Xiang; Shangguan, Zhou-Ping; Zheng, Hai-Lei

    2015-11-01

    Hydrogen sulphide (H2S) is emerging as a potential molecule involved in physiological regulation in plants. However, whether H2S regulates iron-shortage responses in plants is largely unknown. Here, the role of H2S in modulating iron availability in maize (Zea mays L. cv Canner) seedlings grown in iron-deficient culture solution is reported. The main results are as follows: Firstly, NaHS, a donor of H2S, completely prevented leaf interveinal chlorosis in maize seedlings grown in iron-deficient culture solution. Secondly, electron micrographs of mesophyll cells from iron-deficient maize seedlings revealed plastids with few photosynthetic lamellae and rudimentary grana. On the contrary, mesophyll chloroplasts appeared completely developed in H2S-treated maize seedlings. Thirdly, H2S treatment increased iron accumulation in maize seedlings by changing the expression levels of iron homeostasis- and sulphur metabolism-related genes. Fourthly, phytosiderophore (PS) accumulation and secretion were enhanced by H2S treatment in seedlings grown in iron-deficient solution. Indeed, the gene expression of ferric-phytosiderophore transporter (ZmYS1) was specifically induced by iron deficiency in maize leaves and roots, whereas their abundance was decreased by NaHS treatment. Lastly, H2S significantly enhanced photosynthesis through promoting the protein expression of ribulose-1,5-bisphosphate carboxylase large subunit (RuBISCO LSU) and phosphoenolpyruvate carboxylase (PEPC) and the expression of genes encoding RuBISCO large subunit (RBCL), small subunit (RBCS), D1 protein (psbA), and PEPC in maize seedlings grown in iron-deficient solution. These results indicate that H2S is closely related to iron uptake, transport, and accumulation, and consequently increases chlorophyll biosynthesis, chloroplast development, and photosynthesis in plants.

  1. Fertility-dependent effects of ectomycorrhizal fungal communities on white spruce seedling nutrition.

    Science.gov (United States)

    Smith, Alistair J H; Potvin, Lynette R; Lilleskov, Erik A

    2015-11-01

    Ectomycorrhizal fungi (EcMF) typically colonize nursery seedlings, but nutritional and growth effects of these communities are only partly understood. To examine these effects, Picea glauca seedlings collected from a tree nursery naturally colonized by three dominant EcMF were divided between fertilized and unfertilized treatments. After one growing season seedlings were harvested, ectomycorrhizas identified using DNA sequencing, and seedlings analyzed for leaf nutrient concentration and content, and biomass parameters. EcMF community structure-nutrient interactions were tested using nonmetric multidimensional scaling (NMDS) combined with vector analysis of foliar nutrients and biomass. We identified three dominant species: Amphinema sp., Atheliaceae sp., and Thelephora terrestris. NMDS + envfit revealed significant community effects on seedling nutrition that differed with fertilization treatment. PERMANOVA and regression analyses uncovered significant species effects on host nutrient concentration, content, and stoichiometry. Amphinema sp. had a significant positive effect on phosphorus (P), calcium and zinc concentration, and P content; in contrast, T. terrestris had a negative effect on P concentration. In the unfertilized treatment, percent abundance of the Amphinema sp. negatively affected foliar nitrogen (N) concentration but not content, and reduced foliar N/P. In fertilized seedlings, Amphinema sp. was positively related to foliar concentrations of N, magnesium, and boron, and both concentration and content of manganese, and Atheliaceae sp. had a negative relationship with P content. Findings shed light on the community and species effects on seedling condition, revealing clear functional differences among dominants. The approach used should be scalable to explore function in more complex communities composed of unculturable EcMF.

  2. Growth, water relations and photosynthesis of seedlings and resprouts after fire

    Science.gov (United States)

    Clemente, Adelaide S.; Rego, Francisco C.; Correia, Otília A.

    2005-05-01

    Seasonal patterns of growth, water relations, photosynthesis and leaf characteristics were compared between obligate seeders ( Cistus monspeliensis and Cistus ladanifer) and resprouters ( Arbutus unedo and Pistacia lentiscus) from the first to the second year after fire. We hypothesized that seedlings would be more water-limited than resprouts due to their shallower root systems. Regarding water use strategies, Cistus species are drought semi-deciduous and A. unedo and P. lentiscus are evergreen sclerophylls, therefore, comparisons were based on the relative deviation from mature conspecific plants. Seedlings and resprouts had higher shoot elongation and leaf production than mature plants, and over an extended period. Differences from mature plants were larger in resprouts, with two-fold transpiration, leaf conductance and photosynthesis in late spring/early summer. Seedlings of C. monspeliensis exhibited higher transpiration and leaf conductance than mature plants, while those of C. ladanifer only exhibited higher water potential. Growth increments and ameliorated water relations and photosynthesis after fire were attributed to an increase in water and nutrient availability. The small differences in water relations and photosynthesis between seedlings and mature conspecifics are in accordance with the prediction of seedlings experiencing higher water limitation than resprouts. We attribute these results to differences in root systems: resprouters benefited from an increase in root/shoot ratios and the presence of deep roots whereas Cistus seedlings relied on very shallow roots, which cannot provide assess to deep water during summer. Nevertheless, seedlings did not show evidence of experiencing a more severe water limitation than mature conspecifics, which we attributed to the presence of efficient mechanisms of avoiding and tolerating water stress. The results are discussed in relation to post-fire demography of seeders and resprouters in Mediterranean

  3. Effects of methyl jasmonate on accumulation of flavonoids in seedlings of common buckwheat (Fagopyrum esculentum Moench).

    Science.gov (United States)

    Horbowicz, M; Wiczkowski, W; Koczkodaj, Danuta; Saniewski, M

    2011-09-01

    The jasmonates, which include jasmonic acid and its methyl ester (MJ), play a central role in regulating the biosynthesis of many secondary metabolites, including flavonoids, and also are signaling molecules in environmental stresses. Synthesis of anthocyanins pigments is a final part of flavonoids pathway route. Accumulation of the pigments in young seedlings is stimulated by various environmental stresses, such as high-intensity light, wounding, pathogen attack, drought, sugar and nutrient deficiency. The anthocyanins take part in defense system against excess of light and UV-B light, and therefore it is probably main reason why young plant tissues accumulate enlarged levels of the pigments. The effects of exogenously applied MJ on level of anthocyanins, glycosides of apigenin, luteolin, quercetin and proanthocyanidins in seedlings of common buckwheat (Fagopyrum esculentum Moench) were studied. MJ decreased contents of all the found cyanidin glycosides and its aglycone in hypocotyls of buckwheat seedlings. However contents of particular anthocyanins in cotyledons of buckwheat seedlings treated with the plant hormone were not significantly different from the control. Applied doses of MJ did not affect levels of quercetin, apigenin and luteolin glycosides in the analyzed parts of buckwheat seedlings: cotyledons and hypocotyls. On the other hand, treatment of buckwheat seedlings with MJ clearly stimulated of proanthocyanidins biosynthesis in hypocotyls. We suggest that methyl jasmonate induces in hypocotyls of buckwheat seedlings the leucocyanidin reductase or anthocyanidin reductase, possible enzymes in proanthocyanidins synthesis, and/or inhibits anthocyanidin synthase, which transforms leucocyanidin into cyanidin. According to our knowledge this is the first report regarding the effect of methyl jasmonate on enhancing the accumulation of proanthocyanidins in cultivated plants.

  4. Effects of prolonged drought stress on Scots pine seedling carbon allocation.

    Science.gov (United States)

    Aaltonen, Heidi; Lindén, Aki; Heinonsalo, Jussi; Biasi, Christina; Pumpanen, Jukka

    2016-12-14

    As the number of drought occurrences has been predicted to increase with increasing temperatures, it is believed that boreal forests will become particularly vulnerable to decreased growth and increased tree mortality caused by the hydraulic failure, carbon starvation and vulnerability to pests following these. Although drought-affected trees are known to have stunted growth, as well as increased allocation of carbon to roots, still not enough is known about the ways in which trees can acclimate to drought. We studied how drought stress affects belowground and aboveground carbon dynamics, as well as nitrogen uptake, in Scots pine (Pinus sylvestris L.) seedlings exposed to prolonged drought. Overall 40 Scots pine seedlings were divided into control and drought treatments over two growing seasons. Seedlings were pulse-labelled with (13)CO2 and litter bags containing (15)N-labelled root biomass, and these were used to follow nutrient uptake of trees. We determined photosynthesis, biomass distribution, root and rhizosphere respiration, water potential, leaf osmolalities and carbon and nitrogen assimilation patterns in both treatments. The photosynthetic rate of the drought-induced seedlings did not decrease compared to the control group, the maximum leaf specific photosynthetic rate being 0.058 and 0.045 µmol g(-1) s(-1) for the drought and control treatments, respectively. The effects of drought were, however, observed as lower water potentials, increased osmolalities as well as decreased growth and greater fine root-to-shoot ratio in the drought-treated seedlings. We also observed improved uptake of labelled nitrogen from soil to needles in the drought-treated seedlings. The results indicate acclimation of seedlings to long-term drought by aiming to retain sufficient water uptake with adequate allocation to roots and root-associated mycorrhizal fungi. The plants seem to control water potential with osmolysis, for which sufficient photosynthetic capability is needed.

  5. Salt stress-induced seedling growth inhibition coincides with differential distribution of serotonin and melatonin in sunflower seedling roots and cotyledons.

    Science.gov (United States)

    Mukherjee, Soumya; David, Anisha; Yadav, Sunita; Baluška, František; Bhatla, Satish Chander

    2014-12-01

    Indoleamines regulate a variety of physiological functions during the growth, morphogenesis and stress-induced responses in plants. Present investigations report the effect of NaCl stress on endogenous serotonin and melatonin accumulation and their differential spatial distribution in sunflower (Helianthus annuus) seedling roots and cotyledons using HPLC and immunohistochemical techniques, respectively. Exogenous serotonin and melatonin treatments lead to variable effect on hypocotyl elongation and root growth under NaCl stress. NaCl stress for 48 h increases endogenous serotonin and melatonin content in roots and cotyledons, thus indicating their involvement in salt-induced long distance signaling from roots to cotyledons. Salt stress-induced accumulation of serotonin and melatonin exhibits differential distribution in the vascular bundles and cortex in the differentiating zones of the primary roots, suggesting their compartmentalization in the growing region of roots. Serotonin and melatonin accumulation in oil body rich cells of salt-treated seedling cotyledons correlates with longer retention of oil bodies in the cotyledons. Present investigations indicate the possible role of serotonin and melatonin in regulating root growth during salt stress in sunflower. Effect of exogenous serotonin and melatonin treatments (15 μM) on sunflower seedlings grown in the absence or presence of 120 mM NaCl substantiates their role on seedling growth. Auxin and serotonin biosynthesis are coupled to the common precursor tryptophan. Salt stress-induced root growth inhibition, thus pertains to partial impairment of auxin functions caused by increased serotonin biosynthesis. In seedling cotyledons, NaCl stress modulates the activity of N-acetylserotonin O-methyltransferase (HIOMT; EC 2.1.1.4), the enzyme responsible for melatonin biosynthesis from N-acetylserotonin.

  6. Node Detection and Internode Length Estimation of Tomato Seedlings Based on Image Analysis and Machine Learning

    Directory of Open Access Journals (Sweden)

    Kyosuke Yamamoto

    2016-07-01

    Full Text Available Seedling vigor in tomatoes determines the quality and growth of fruits and total plant productivity. It is well known that the salient effects of environmental stresses appear on the internode length; the length between adjoining main stem node (henceforth called node. In this study, we develop a method for internode length estimation using image processing technology. The proposed method consists of three steps: node detection, node order estimation, and internode length estimation. This method has two main advantages: (i as it uses machine learning approaches for node detection, it does not require adjustment of threshold values even though seedlings are imaged under varying timings and lighting conditions with complex backgrounds; and (ii as it uses affinity propagation for node order estimation, it can be applied to seedlings with different numbers of nodes without prior provision of the node number as a parameter. Our node detection results show that the proposed method can detect 72% of the 358 nodes in time-series imaging of three seedlings (recall = 0.72, precision = 0.78. In particular, the application of a general object recognition approach, Bag of Visual Words (BoVWs, enabled the elimination of many false positives on leaves occurring in the image segmentation based on pixel color, significantly improving the precision. The internode length estimation results had a relative error of below 15.4%. These results demonstrate that our method has the ability to evaluate the vigor of tomato seedlings quickly and accurately.

  7. Controlled release fertilizer and container volumes in the production of Parapiptadenia rigida (Benth. Brenan seedlings

    Directory of Open Access Journals (Sweden)

    Ezequiel Gasparin

    2015-10-01

    Full Text Available Growing demand for native tree seedlings will require improvements in quality standards of production processes through the use of more efficient cultivation techniques. This study evaluated the effects of different doses of controlled release fertilizer (CRF and different container volumes in the production of Parapiptadenia rigida seedlings. We examined the effects of five different concentrations (0, 3, 6, 9 and 12 g L-1 substrate of CRF (18-5-9 NPK and three different container volumes (50, 110 and 180 cm3 on seedling height (H and collar diameter (CD measured monthly for seven months and then calculated H/CD ratios. After 210 days of growth, the dry masses of the aerial portions, root systems, and total masses were determined, as well as the concentrations of macro- and micronutrients in the aerial portions of the seedlings. In general, the dose 9 g L-1 substrate combined with the 180 cm3 cultivation tubes demonstrated the best results in terms of the morphological variables analyzed, resulting in consistent quality seedlings for field planting.

  8. Assessment of salinity tolerance in rice using seedling based morpho-physiological indices

    Directory of Open Access Journals (Sweden)

    Syed Adeel Zafar

    2015-08-01

    Full Text Available Background: Salinity is among the most damaging abiotic stresses for rice production which limits its growing area. The present research was conducted to evaluate five rice varieties for salinity tolerance at seedling stage. Methods: Experiment was conducted in triplicate and in two sets. One set was grown as a control (non-stress and other as salt stressed. Salt stress of 15 dS/m was applied to one set of rice seedlings under controlled conditions. Data for different growth related morpho-physiological traits, i.e. germination percentage, root and shoot length, seedling fresh and dry weight, Na+ and K+ uptake were recorded after 15 days of seedling emergence under control as well as salinity condition. Results: Significant differences were observed among the genotypes under both the treatments and interaction of the evaluated traits suggested a significant variability among the rice genotypes under salt stress. NIAB-IRRI-9, Basmati-198 and KSK-133 were proved to be relatively salt tolerant varieties as they showed good performance for the recorded parameters. However, Basmati-385 was observed a salt sensitive variety due to highest reduction in seedling fresh and dry weight along with the maximum Na+ uptake. Conclusion: Based on obtained results, it was concluded that the evaluated morpho-physiological traits were useful to screen rice cultivars for salinity stress. In addition, NIAB-IRRI-9, Basmati-198 and KSK-133 can be used in breeding programs as tolerant check and Basmati-385 can be used as sensitive check.

  9. Variation Analysis of Seed and Seedling Traits of Cross Combination Progenies in Populus

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Twenty-five species and hybrids in Populus were used as parents, and 26 cross combinations, including more than 5 000 seedlings, were obtained by artificial cross breeding. The length of infructescence, number of seeds per infructescence, thousand-seed weight, germination rate of seeds among these cross combinations were tested. The results indicated that the cross combinational effects were significant for these traits, and demonstrated that the length of infructescence, thousand-seed weight were positively affected by female parent. In addition, seedling height, diameter above ground, diameter at breast height (DBH) of 17 cross combination progenies were investigated. The analysis of mean and standard deviation of these three traits showed that seedling height, diameter above ground, DBH had extensive variation among combinations and individuals within combination. Variance analysis and estimate of heritability indicated that the three traits had wide variation and were controlled by heredity. It was feasible to select superior cross combinations and seedlings. Further more, the result of multiple comparison showed that P. deltoides 'Lux' × P. deltoides 'D324', P. ussuriensis cl. 'U4' × P. deltoides 'T66', P. ussuriensis cl. 'U4' × P. deltoides 'T26', P. deltoides 'Lux' × P. ussuriensis cl. 'U3', (P. tomentosa × P. bolleana) × (P. alba × P. glandulosa), (P. alba × P. tomentosa) × (P. alba × P. glandulosa ), and (P. alba × P. glandulosa 'No. 2') × P. tomentosa 'Lumao 50' were superior cross combinations with higher growth rate. Finally, 123 elite seedlings were selected for further test.

  10. Alternative substrates in the production of lettuce seedlings and their productivity in the field

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    Gustavo Castoldi

    Full Text Available Based on the hypothesis that alternative substrates should improve the yield of lettuce crops by producing better quality seedlings, the objective of this work was to evaluate the effect of different substrates on the production of seedlings of this species, and their growth in the field. The study was in two stages. The first consisted of the production of lettuce seedlings, and the second assessed their development in the field. Four alternative substrates were tested, obtained by mixing together a sieved vermicompost from which all clumps had been removed, sterilized sand, charred rice husks and basalt powder. The commercial substrate, Plantmax HA®, was also tested. In the first phase, which was conducted in a completely randomised design with four replications, the height, root length, number of leaves, leaf area and dry weight of the seedlings were all evaluated 28 days after sowing. In the second phase, which was carried out in the field in a randomised block design with four replications, the plants were harvested 50 days after transplanting and the head diameter, fresh weight, number of leaves and leaf and stem dry weight were evaluated. The alternative substrates produced larger seedlings in less time than the commercial substrate, resulting in a reduction of 10 days in the total crop cycle. The reduction in the time between sowing and harvesting, together with those aspects relating to sustainability, are the main advantages of the use of alternative substrates, since in the field crop production did not differ between treatments.

  11. Protection of the photosynthetic apparatus from extreme dehydration and oxidative stress in seedlings of transgenic tobacco.

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    Concepción Almoguera

    Full Text Available A genetic program that in sunflower seeds is activated by Heat Shock transcription Factor A9 (HaHSFA9 has been analyzed in transgenic tobacco seedlings. The ectopic overexpression of the HSFA9 program protected photosynthetic membranes, which resisted extreme dehydration and oxidative stress conditions. In contrast, heat acclimation of seedlings induced thermotolerance but not resistance to the harsh stress conditions employed. The HSFA9 program was found to include the expression of plastidial small Heat Shock Proteins that accumulate only at lower abundance in heat-stressed vegetative organs. Photosystem II (PSII maximum quantum yield was higher for transgenic seedlings than for non-transgenic seedlings, after either stress treatment. Furthermore, protection of both PSII and Photosystem I (PSI membrane protein complexes was observed in the transgenic seedlings, leading to their survival after the stress treatments. It was also shown that the plastidial D1 protein, a labile component of the PSII reaction center, and the PSI core protein PsaB were shielded from oxidative damage and degradation. We infer that natural expression of the HSFA9 program during embryogenesis may protect seed pro-plastids from developmental desiccation.

  12. Chilling Tolerance Improving of Watermelon Seedling by Salicylic Acid Seed and Foliar Application

    Directory of Open Access Journals (Sweden)

    Mohammad SAYYARI

    2013-02-01

    Full Text Available Chilling temperatures lead to numerous physiological disturbances in the cells of chilling-sensitive plants and result in chilling injury and death of tropical and subtropical plants such as watermelon. In this study, the possibility of cold stress tolerance enhancing of watermelon seedling (Citrullus lanatus by exogenous application of Salicylic acid (SA was investigated. SA was applied through seed soaking or foliar spray at 0, 0.5, 1 and 1.5 mM concentration. After SA treatment, the seedlings were subjected to chilling 5 h/day at 4°C for 5 days. Statistical analysis showed significant effects of the application methods and SA concentrations on plant growth parameters, photosynthetic pigments, electrolyte leakage, proline and chilling injury index. SA application improved growth parameters and increased chlorophyll content of watermelon seedling subjected to chilling stress and provided significant protection against chilling stress compared to non-SA-treated seedlings. Although two SA application methods improved chilling stress tolerance, seed soaking method provided better protection compared to foliar spray method. SA ameliorated the injury caused by chilling stress via inhibiting proline accumulation and leaf electrolyte leakage. The highest cold tolerance was obtained with 0.5 mM SA application. Results indicate that SA could be used effectively to protect watermelon seedling from damaging effects of chilling stress at the early stages of growth.

  13. Physiological responses of seeds and seedlings of lettuce submitted to Philodendron bipinnatifidum extract

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    Tiago Zanatta Aumonde

    2013-12-01

    Full Text Available The work was conducted to evaluate the effect of different Philodendron bipinnatifidum Schott. extract concentrations on the physiology and enzymatic metabolism of lettuce seeds and seedlings. The treatments extracts of mature leaves at concentrations of 0, 6, 12, 25 and 50%. Were evaluated the germination, first count germination, speed and germination speed index, length of shoot and primary root, seedling total dry mass, electrical conductivity, chlorophyll content, activity of the enzymes ?-amilase, superoxide dismutase, catalase and ascorbarto peroxidase, lipid peroxidation, hydrogen peroxide content and seedling emergence, length of shoot and total dry mass of emerged seedlings. There was a reduction of germination, germination speed index and total dry mass by increasing the concentration of the extract. While the content of hydrogen peroxide, lipid peroxidation and activity of superoxide dismutase, catalase and peroxidase ascorbarto increased with concentration. The increasing of concentration the leaf extracts of the P. bipinnatifidum negatively affects the activity of the enzyme ?-amylase and causes increase in the activity of antioxidant enzymes, affecting the physiologic performance and growth of lettuce seedlings.

  14. Evaluation of nitrogen content in cabbage seedlings using hyper-spectral images

    Science.gov (United States)

    Chen, Suming; Chen, Chia-Tseng; Wang, Ching-Yin; Yang, I.-Chang; Hsiao, Shih-Chieh

    2007-09-01

    Monitoring of nutrient status of crops is essential for better management of crop production. Nitrogen is one of the most important elements in fertilizer for the growth and yield of vegetable crops. In this study, nitrogen content of cabbage seedlings was evaluated using hyper-spectral images. Cabbage seedlings, cultured at five nitrogen fertilization levels, were planted in the 128-cell plug trays and grown in a phytotron at National Taiwan University. The images, ranged from 410 to 1090 nm, of cabbage seedlings were analyzed by a hyper-spectral imaging system consisting of CCD cameras with liquid crystal tunable filters (LCTF), which was developed in this study. The digital images of seedling canopies were processed including image segmentation, gray level calibration and absorbance conversion. Models including modified partial least square regression (MPLSR), step-wise multi-linear regression (SMLR) and artificial neural network with cross-learning strategy (ANN-CL) were developed for the determination of the nitrogen content in cabbage seedlings. The three significant wavelengths derived from SMLR model are 470, 710, and 1080; and the best result is obtained by ANN-CL model, in which r c=0.89, SEC=6.41 mg/g, r v=0.87, and SEV=6.96 mg/g. The ANN-CL model is more suitable for the remote sensing in precision agriculture applications because not only its model accuracy but also only 3 wavelengths are needed.

  15. Germination and Seedling Development of Seeds from Different Parkia biglobosa (Jacq G. Don Trees

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    Christiana O. ADEYEMI

    2013-02-01

    Full Text Available The effect of daylight, continuous illumination and acid scarification on the seed germination and seedling vegetative growth (epicotyl and hypocotyl lengths, and number of secondary roots of different Parkia biglobosawere investigated in the Plant Physiology Laboratory University of Ilorin, Ilorin Kwara State Nigeria. Seeds from two out of the twenty six Parkia tree samples (trees B and T germinated within 24 hours of planting in the daylight germination study while seeds from another tree (Q did not germinate until the third week after planting (3WAP. Some seeds have higher germination percentage both in the daylight (preliminary germination study and in the continuous light (illuminated study. The treatment with concentrated Sulphric acid (conc. H2SO4was effective in breaking the seed dormancy as seeds from eight (8 trees produced one hundred percent (100% germination. At p= 0.05 the length of epicotyl and hypocoty1 lengths were significantly different as seedling vegetative growth were long in the seedlings from the daylight experiment than the continuous light experiment. The vegetative growths of the seedlings from the scarified seed were longer at 15min of scarification in all except in trees F and Z. It was observed that the time of scarification affect the both seed germination and seedling development.

  16. Low root reserve accumulation during drought may lead to winter mortality in poplar seedlings.

    Science.gov (United States)

    Galvez, David A; Landhäusser, S M; Tyree, M T

    2013-04-01

    Climate models suggest that more frequent drought events of greater severity and length, associated with climate change, can be expected in the coming decades. Although drought-induced tree mortality has been recognized as an important factor modulating forest demography at the global scale, the mechanisms underlying drought-induced tree mortality remain contentious. Above- and below-ground growth, gas exchange, water relations and carbon reserve accumulation dynamics at the organ and whole-plant scale were quantified in Populus tremuloides and P. balsamifera seedlings in response to severe drought. Seedlings were maintained in drought conditions over one growing and one dormant winter season. Our experiment presents a detailed description of the effect of severe drought on growth and physiological variables, leading to seedling mortality after an extended period of drought and dormancy. After re-watering following the dormant period, drought-exposed seedlings did not re-flush, showing that the root system had died off. The results of this study suggest a complex series of physiological feedbacks between the measured variables in both Populus species. Further, they reveal that reduced reserve accumulation in the root system during drought decreases the conversion of starch to soluble sugars in roots, which may contribute to the root death of drought-exposed seedlings during the dormant season by compromising the frost tolerance of the root system. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  17. Gibberellin mediates the development of gelatinous fibres in the tension wood of inclined Acacia mangium seedlings.

    Science.gov (United States)

    Nugroho, Widyanto Dwi; Nakaba, Satoshi; Yamagishi, Yusuke; Begum, Shahanara; Marsoem, Sri Nugroho; Ko, Jae-Heung; Jin, Hyun-O; Funada, Ryo

    2013-11-01

    Gibberellin stimulates negative gravitropism and the formation of tension wood in tilted Acacia mangium seedlings, while inhibitors of gibberellin synthesis strongly inhibit the return to vertical growth and suppress the formation of tension wood. To characterize the role of gibberellin in tension wood formation and gravitropism, this study investigated the role of gibberellin in the development of gelatinous fibres and in the changes in anatomical characteristics of woody elements in Acacia mangium seedlings exposed to a gravitational stimulus. Gibberellin, paclobutrazol and uniconazole-P were applied to the soil in which seedlings were growing, using distilled water as the control. Three days after the start of treatment, seedlings were inclined at 45 ° to the vertical and samples were harvested 2 months later. The effects of the treatments on wood fibres, vessel elements and ray parenchyma cells were analysed in tension wood in the upper part of inclined stems and in the opposite wood on the lower side of inclined stems. Application of paclobutrazol or uniconazole-P inhibited the increase in the thickness of gelatinous layers and prevented the elongation of gelatinous fibres in the tension wood of inclined stems. By contrast, gibberellin stimulated the elongation of these fibres. Application of gibberellin and inhibitors of gibberellin biosynthesis had only minor effects on the anatomical characteristics of vessel and ray parenchyma cells. The results suggest that gibberellin is important for the development of gelatinous fibres in the tension wood of A. mangium seedlings and therefore in gravitropism.

  18. Effects of rhizobacteria on the respiration and growth of Cerasus sachalinensis Kom. seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Qin, S.; Zhou, W.; Li, Z.; Lyu, D.

    2016-11-01

    In this study, we investigated the influence of rhizosphere microorganisms on seed germination and root metabolism in Cerasus sachalinensis Kom. We inoculated C. sachalinensis plants with suspensions of dominant bacterial strains isolated from their rhizosphere. Four bacterial strains each with significant growth-promoting or growth-inhibiting effects were screened from the efficient root-colonizing microorganisms. The number of actinomycetes increased and that of fungi decreased significantly in the seedling rhizospheres after rhizobacteria treatment. The growth-promoting bacteria slightly affected the respiration rates and respiratory pathway enzymes, but significantly improved root viability, root carbohydrate concentration and seedling growth. Bacillus cereus, Staphylococcus sp. and Pseudomonas fluorescens were identified as the growth-promoting rhizobacteria; one strain could not be identified. After inoculation with the growth-inhibiting bacteria, the number of fungal colonies in the seedling rhizospheres increased and root viability and respiration rate as well as starch and sucrose accumulation in the roots significantly decreased. The glycolysis, pentose phosphate and alternative oxidase pathways became the major pathways of respiratory metabolism after inoculation with the growth-inhibiting bacteria. The height, leaf number, growth and dry weight of the seedlings decreased significantly in plants inoculated with the growth-inhibiting bacteria. Inoculation of C. sachalinensis rhizosphere with growth-promoting and growth-inhibiting bacteria affected the soil environmental factors such as microbial group composition, nutrient concentration and seedling biomass. (Author)

  19. Can environmental variation affect seedling survival of plants in northeastern Mexico?

    Directory of Open Access Journals (Sweden)

    García Jaime F.

    2011-01-01

    Full Text Available The effects of global warming increase the frequency and intensity of many climate events such as rainfall. We evaluated the effects of environmental conditions on early stage seedling survival of the native thorn scrub species Caesalpinia mexicana A. Gray, Celtis pallida Torr., Cordia boissieri A. DC., and Ebenopsis ebano (Berland. Barneby and J.W. Grimes, during the summer of 2009 and 2010. The experimental design had two factors, two levels of rainfall and three microhabitats of thorn scrub: (i open interspace, (ii thorn scrub edge and (iii under the canopy of dense thorn scrub. In dense thorn scrub, seedling survival was higher for Caesalpinia mexicana and Celtis pallida, and for Cordia boissieri and Ebenopsis ebano seedling survival was higher in dense thorn scrub and thorn scrub edge. The effect of rainfall on seedling survival depended on the year. Rainfall in 2010 and dense thorn scrub increased seedling survival of native species. For survival, the limiting factors of microhabitats appear to change across the years. Besides rainfall events, biological aspects like competition and mycorrhiza effects would need to be considered in models of plant establishment.

  20. Expression of stress-related genes in zebrawood (Astronium fraxinifolium, Anacardiaceae seedlings following germination in microgravity

    Directory of Open Access Journals (Sweden)

    Peter W. Inglis

    2014-01-01

    Full Text Available Seeds of a tropical tree species from Brazil, Astronium fraxinifolium, or zebrawood, were germinated, for the first time in microgravity, aboard the International Space Station for nine days. Following three days of subsequent growth under normal terrestrial gravitational conditions, greater root length and numbers of secondary roots was observed in the microgravity-treated seedlings compared to terrestrially germinated controls. Suppression subtractive hybridization of cDNA and EST analysis were used to detect differential gene expression in the microgravity-treated seedlings in comparison to those initially grown in normal gravity (forward subtraction. Despite their return to, and growth in normal gravity, the subtracted library derived from microgravity-treated seedlings was enriched in known microgravity stress-related ESTs, corresponding to large and small heat shock proteins, 14-3-3-like protein, polyubiquitin, and proteins involved in glutathione metabolism. In contrast, the reverse-subtracted library contained a comparatively greater variety of general metabolism-related ESTs, but was also enriched for peroxidase, possibly indicating the suppression of this protein in the microgravity-treated seedlings. Following continued growth for 30 days, higher concentrations of total chlorophyll were detected in the microgravity-exposed seedlings.

  1. Belowground Competition Directs Spatial Patterns of Seedling Growth in Boreal Pine Forests in Fennoscandia

    Directory of Open Access Journals (Sweden)

    E. Petter Axelsson

    2014-09-01

    Full Text Available Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above- and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

  2. Chilling Tolerance Improving of Watermelon Seedling by Salicylic Acid Seed and Foliar Application

    Directory of Open Access Journals (Sweden)

    Mohammad SAYYARI

    2013-02-01

    Full Text Available Chilling temperatures lead to numerous physiological disturbances in the cells of chilling-sensitive plants and result in chilling injury and death of tropical and subtropical plants such as watermelon. In this study, the possibility of cold stress tolerance enhancing of watermelon seedling (Citrullus lanatus by exogenous application of Salicylic acid (SA was investigated. SA was applied through seed soaking or foliar spray at 0, 0.5, 1 and 1.5 mM concentration. After SA treatment, the seedlings were subjected to chilling 5 h/day at 4°C for 5 days. Statistical analysis showed significant effects of the application methods and SA concentrations on plant growth parameters, photosynthetic pigments, electrolyte leakage, proline and chilling injury index. SA application improved growth parameters and increased chlorophyll content of watermelon seedling subjected to chilling stress and provided significant protection against chilling stress compared to non-SA-treated seedlings. Although two SA application methods improved chilling stress tolerance, seed soaking method provided better protection compared to foliar spray method. SA ameliorated the injury caused by chilling stress via inhibiting proline accumulation and leaf electrolyte leakage. The highest cold tolerance was obtained with 0.5 mM SA application. Results indicate that SA could be used effectively to protect watermelon seedling from damaging effects of chilling stress at the early stages of growth.

  3. Potential impacts of using sewage sludge biochar on the growth of plant forest seedlings

    Directory of Open Access Journals (Sweden)

    Maria Isidoria Silva

    Full Text Available ABSTRACT: Sewage sludge has long been successfully used in the production of nursery plants; however, some restriction may apply due to its high pathogenic characteristics. The process of charring the organic waste significantly reduces that undesired component and may be as effective as the non-charred residue. The aim of this study was to evaluate the effect of sewage sludge biochar on the growth and morphological traits of eucalyptus ( Eucalyptus grandis L. seedlings, and compare results with those observed when using uncharred sewage sludge. Treatments were arranged in a completely randomized design, in a 2 x 2 factorial scheme, with four replications. Charred and non-charred sewage sludge were tested with and without NPK addition. A control treatment was also evaluated. Ten weeks old eucalyptus seedlings were transferred to the pots and grew for eight weeks. Chlorophyll content, plant height and stem diameter were measured at 0, 30 and 60 days after transplant. Shoot and root biomass were measured after plant harvest. Dickson Quality Index was calculated to evaluate the overall quality of seedlings. Biochar was effective in improving the seedlings quality, and had similar effects as the non-charred waste. Therefore, sewage sludge biochar has the potential to improve the process of production of forest species seedlings and further reduce the environmental risks associated with the use of non-charred sewage sludge.

  4. Nutrient element contents of cutting seedlings of hybrid species ( Liriodendron chinense x tulipifera)

    Institute of Scientific and Technical Information of China (English)

    ZHANGXiao-ping; FANGYan-ming; DINGYu-long

    2003-01-01

    The cutting seedlings of Liriodendron chinense x tulipifera were treated with the different concentrations of auxin (treatmenh: IBA of 50 g·kg-1 + NAA of 300 g·kg-1; treatment2- IBA of 100 g·kg-1 + NAA of 300 g·kg-1). The biomass and the nutrient element contents for different organs (root, stem, leaf) of cutting seedling of Liriodendron chinense x tulipifera were measured by the dry method, Kjeldahl method and Atomic Absorption Spectroscopy method. The result showed that the biomass of root, stem, and leaf of the cutting seedling treated with auxin was all remarkably increased. The contents of element C in root, stem and leaf had no significant difference between the control and auxin treatments, while the contents of N, P, K and Ca in stem were much lower than that in leaf and root. Variance analysis showed that for the same organ with different concentration treatment of auxin, the four nutrient elements (N, P, K, and Ca) had no significant difference in contents, while there existed significant or very significant difference in contents of the four nutrient elements in different organs with the same concentration auxin treatment. The N, P, K and Ca contents were very low in cutting seedlings; as a result, additional fertilizer should be applied to the seedlings when they were planted in the field.

  5. Specific effects of certain salts on nitrogen metabolism of young corn seedlings

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    Mohammad Hatata

    2014-01-01

    Full Text Available The effect of sodium and magnesium chlorides and sulphates on nitrogen metabolism of corn seedlings and their constituent parts have been studied. Treatment with all salts led to a decrease in the nitrogen content of the seedling as a whole, and the decrease became more pronounced with the increase of salt concentration, though these concentrations were too low to induce any osmotic action. The same trend of changes was noticed as regards nonprotein-N, whereas the opposite was recorded in reference to the changes; of protein-N. Higher concentrations of the salt solutions led to leaching out of more nonprotein-N than did lower concentrations. The study of the distribution of nitrogenous constituents among the different organs of the seedling showed that while the total-N content of the whole seedling decreased with the increase of salt concentration, the total-N content of the roots decreased markedly, and the total-N content of the tops decreased also but less whereas, the total-N content of the grains increased with the increase of salt concentration as compared with that in the control. As a result of disturbances of nitrogen metabolism under salinization, more ammonia and amides were accumulated in all seedling organs.

  6. Colonization of tomato seedlings by bioluminescent Clavibacter michiganensis subsp. michiganensis under different humidity regimes.

    Science.gov (United States)

    Xu, Xiulan; Rajashekara, Gireesh; Paul, Pierce A; Miller, Sally A

    2012-02-01

    Tomato bacterial canker, caused by Clavibacter michiganensis subsp. michiganensis, is transmitted by infected or infested seed and mechanically from plant to plant. Wounds occurring during seedling production and crop maintenance facilitate the dissemination of the pathogen. However, the effects of environmental factors on C. michiganensis subsp. michiganensis translocation and growth as an endophyte have not been fully elucidated. A virulent, stable, constitutively bioluminescent C. michiganensis subsp. michiganensis strain BL-Cmm 17 coupled with an in vivo imaging system allowed visualization of the C. michiganensis subsp. michiganensis colonization process in tomato seedlings in real time. The dynamics of bacterial infection in seedlings through wounds were compared under low (45%) and high (83%) relative humidity. Bacteria multiplied rapidly in cotyledon petioles remaining after clip inoculation and moved in the stem toward both root and shoot. Luminescent signals were also observed in tomato seedling roots over time, and root development was reduced in inoculated plants maintained under both humidity regimes. Wilting was more severe in seedlings under high-humidity regimes. A strong positive correlation between light intensity and bacterial population in planta suggests that bioluminescent C. michiganensis subsp. michiganensis strains will be useful in evaluating the efficacy of bactericides and host resistance.

  7. Growth of Scots Pine and Silver Birch Seedlings on Different Nursery Container Media

    Directory of Open Access Journals (Sweden)

    Fahrettin TILKI

    2014-12-01

    Full Text Available Peat has been the most common growing medium in tree nurseries, either alone or as a component of growing media mixes. However, as a result of increasing costs and decreasing amount of peat, seedling-growers are seeking more local growing medium components. In this study, container seedlings of Scots pine (Pinus sylvestris L. and silver birch (Betula pendula Roth were grown in pure peat and peat mixtures containing perlite and zeolite.  Physical parameters (height, shoot diameter, root dry weight, shoot dry weight, total dry weight were measured along with several morphological parameters (sturdiness quotient, height/diameter, shoot/root ratio. The zeolite additive in peat changed some media properties, and significant relation was established between some morphological attributes of seedlings and some medium properties in both species. On average, the seedlings grew best in pure peat, but zeolite additions to peat did not affect some morphological parameters negatively. The results suggest that zeolite has potential to be used as a component of peat based growing medium mixtures, and addition of zeolite to peat container medium in proportions of 10% by volume in Scots pine and up to 20% in silver birch was shown to be a feasible material for growing Scots pine and silver birch seedlings.

  8. Effect of Arbuscular Mycorrhiza on the Drought Tolerance of Poncirus trifoliata Seedlings

    Institute of Scientific and Technical Information of China (English)

    Wu Qiangsheng; Xia Renxue; Hu Zhengjia

    2006-01-01

    The effects of Glomus mosseae colonization on the plant growth and drought tolerance of 1-year-old trifoliate Poncirus trifoliata seedlings in potted culture were studied in natural water stress and rewatering conditions.Results showed that arbuscular mycorrhizal (AM)inoculation significantly improved the height,stem diameter,and fresh weight of P.trifoliata seedlings before natural water stress.By the end of the experiment,the survival percentage of AM-transplanted seedlings was 8%higher than those of non-AM ones.During water stress and rewatering,AM significantly increased the contents of soluble sugars and proteins in leaves,and enhanced the activities of superoxide dismutase (SOD),guaiacol peroxidase (G-POD),and catalase (CAT) in either seedling leaves or roots,which indicated that AM colonization could improve the osmotic adjustment response of P.trifoliata,enhance its defense system,and alleviate oxidative damages to membrane lipids and proteins.These results demonstrated that the drought tolerance of P.trifoliata seedlings was increased by inoculation with AM fungi.The functional mechanism underlying the observation that mycorrhizas increased the host's drought tolerance was closely related to enzymatic and nonenzymatic antioxidant defense systems such as SOD,GPOD,CAT,and soluble protein.

  9. Magnetically treated water irrigation effect on turnip seed germination, seedling growth and enzymatic activities

    Directory of Open Access Journals (Sweden)

    Zia ul Haq

    2016-06-01

    Full Text Available Pre-sowing magnetic field seed treatment effects on biological characteristics of vegetables and crops have been studied well. However, studies reporting irrigation with magnetically treated water are scanty. Therefore, the effect of irrigation with magnetically treated water on turnip seed germination, seedling growth and enzymatic activities was evaluated. The tap water was treated at 211 mT for 30, 45 and 60 min and used for irrigation of turnip seed and seedlings. Uniform and healthy turnip seed was sown under randomized complete block design (RCBD. The germination, emergence rate index, vigor index I and vigor index II increased up to 28.33%, 11.54%, 57.59% and 32.26%, respectively. The growth parameters such as seedling lengths, fresh & dry weights, chlorophyll content were also enhanced in response of irrigation with magnetically treated water. The seedlings irrigated with magnetically treated water showed 28.92%, 11.36% and 14.76% higher protein content, alpha amylase and protease activities, respectively vs control. Results revealed that irrigation with magnetically treated water has potential to improve turnip germination, seedling growth and enzymatic activities and this study is also extendable to other vegetables and crops for the improvement of germination and growth.

  10. Second year effects of clouds and ozone on red spruce seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Pier, P.A.; Thornton, F.C.; McDuffie, C. Jr. (Tennessee Valley Authority, Muscle Shoals, AL (USA))

    1990-05-01

    Potted native and phyton-grown red spruce seedlings were exposed for a second growing season to ozone and/or acid deposition in open-top field chambers on Whitetop Mountain, VA (elevation 1,680 m). Chamber treatments were (1) exclusion of clouds and 50% reduction in ambient ozone (COE), (2) ozone with clouds excluded (CE), and (3) exposure to clouds and ozone, as control chambers (CO), and (4) open plots (AA). No differences were detected among treatments for biomass accumulation or for chlorophyll and carotenoid concentrations. Phyton seedlings in AA and CO treatments maintained high photosynthetic rates through October, whereas rates in CE and COE decreased, suggesting that dormancy and winter hardiness were delayed in AA and CO, possibly making seedlings susceptible to early frosts. Respiration of both seedling types was higher for AA and CO throughout most of the growing season, which could lead to depletion of carbohydrates, and eventually to a reduction in growth and vigor of the seedlings over time due to air pollution.

  11. Effect of planting density on plant growth and camptothecin content of Camptotheca acuminata seedlings

    Institute of Scientific and Technical Information of China (English)

    WEIHuan-yong; WANGYang; WANGZhen-yue; YANXiu-feng

    2005-01-01

    C. acuminata seedlings cultivated in greenhouse were transplanted into the fields with 5 designed planting densities (11, 16, 25,44 and 100 plants·m-2) in May of 2004 and were harvested in the middle of September of 2004. The seedling growth indexes including plant height and crown width, biomass allocation, camptothecin (CPT) content and CPT yield of different organs (young leaf, old leaf, stem,and root) were studied. For the 5 selected planting densities, the plant biomass, height, crown width, and total leaf area of C. acuminata seedlings all showed highest values at the planting density of 25 plants ·m-2. CPT content in young leaves was higher than that in other organs of seedlings and presented an obvious change with the variation of planting densities and with the highest value at density of 100plants·m-2, while for other organs no significant variation in CPT content was found with change of planting density. The accumulation of CPT was enhanced significantly at the planting density of 25 plants·m-2. It is concluded that for the purpose to get raw materials with more CPT from C. acuminata, the optimal planting density of C. acuminata seedlings should be designed as 25 plants·m-2.

  12. Artificial seed germination and seedling production ofZostera marina L. by salinity manipulation

    Institute of Scientific and Technical Information of China (English)

    LIU Yunlong; ZHANG Xuelei; SONG Wei; WANG Zongling

    2016-01-01

    Vast declines inZostera marina seagrass beds demand effective methods of rehabilitation. In this study, we developed a practical method by reducing salinity to induce seed germination followed with recovering salinity to facilitate seedling production ofZ. marina. The results showed thatZ. marina seeds collected from natural seawater (salinity 30) were induced to germinate at reduced salinities. Percent germination (GR) was higher and mean-time-to-germinate (MTG) was shorter at lower salinities. The highestGR and shortestMTG occurred at salinity 0 (deionized freshwater). After germination in freshwater, seeds could develop into seedlings at salinities 5–30 and continue the growth. Viability or development of germinated seeds was not significantly different during the 40 d of post-germination incubation at salinities 5–15 after 1–20 d of germination in freshwater. However, during the process of translating germinated seeds from salinity 0 and 5 to salinity 30, reducing the gradients of post-germination acclimation facilitated more seeds forming seedlings in less time. On average, after 60 d of static incubation, including 20 d in freshwater for germination followed with immediate shift to salinity 5 and increasing to salinity 30 at increment of 5 every two days until cultivation at constant salinity 30, 33% ofZ. marina seeds produced healthy seedlings. The results indicate that the salinity-manipulation based method of artificial germination and seedling production is practical and effective in supporting rehabilitation ofZ. marina bed.

  13. Anthocyanin Accumulation Mediated by Blue Light and Cytokinin in Arabidopsis Seedlings

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    It has been reported that pigmentation in plants is stimulated by light and cytokinin (CTK); however, the signaling pathways and the relationship between light and CTK involved in the regulation of anthocyanin accumulation remain to be elucidated. We investigated (i) the role of blue light (BL) and CTK in anthocyanin accumulation; and (ii) the relationship between BL and CTK in wild type (WT) and hy4 mutants of Arabidopsis thaliana. Two-d-old seedlings grown on medium with or without kinetin (KT) or zeatin (ZT) in darkness were irradiated using BL at different fluence rates for 3 d before the anthocyanin content was determined using a spectrophotometric method. Anthocyanin accumulation was strongly induced by BL in WT seedlings but not in hy4 seedlings, which demonstrated that CRY1 is the main photoreceptor for BL. Both KT and ZT enhanced the response of the WT seedlings to BL in a dose-dependent manner, whereas they were not sufficient to promote anthocyanin accumulation in darkness. In addition, data from experiments using the hy4 mutant showed that the CTK effect of BL was also CRY1-dependent. The results from experiments with three different treatment programs showed that the relationship between BL and KT in anthocyanin accumulation of Arabidopsis seedlings seems neither multiplicative nor additive coaction, but rather interaction. BL is necessary for anthocyanin accumulation, and KT might be involved in the BL signaling pathway.

  14. [Effects of coat and sowing depth on seed germination and early seedling growth of Quercus wutaishanica].

    Science.gov (United States)

    Yan, Xing-Fui; Qiu, Zhi-Hu; Zhang, Qiang; Zhang, Kao-Wen; Zhou, Yun-Feng

    2014-01-01

    Under shade environment in glasshouse, the effects of seed coat and sowing depth (0, 2, 5, 10 or 15 cm) on seed germination and early seedling growth of Quercus wutaishanica were studied. Seed coat had obvious inhibiting effects on the germination of Q. wutaishanica seeds. The germination percentage of uncoated seeds increased significantly, averagely by 19.4% at different sowing depths. The germination index and vigor index were increased significantly and the germination was speeded in the peeling treatment. The germination percentages of uncoated and coated seeds were the highest at the sowing depth of 2 cm with 78.9% and 62.2%, respectively. The germination index and vigor index were the highest at the sowing depth of 2 cm, while the coefficient of rate of germination were the highest at the sowing depth of 5 cm. Leaf area per seedling and dry mass of seedlings increased significantly in the peeling treatment compared with those in the unpeeling treatment, but specific root length decreased significantly. The shoot height in the peeling and unpeeling treatments were the highest at the sowing depth of 5 cm with 13.8 and 14.2 cm, respectively. With the increasing of sowing depth, the basal stem diameter of seedlings increased, but tap-root length, number of lateral root and maximum of lateral root all decreased. Sowing depth had little influence on dry mass of seedlings.

  15. Drought and shade deplete nonstructural carbohydrate reserves in seedlings of five temperate tree species.

    Science.gov (United States)

    Maguire, Andrea J; Kobe, Richard K

    2015-12-01

    Plants that store nonstructural carbohydrates (NSC) may rely on carbon reserves to survive carbon-limiting stress, assuming that reserves can be mobilized. We asked whether carbon reserves decrease in resource stressed seedlings, and if NSC allocation is related to species' relative stress tolerances. We tested the effects of stress (shade, drought, and defoliation) on NSC in seedlings of five temperate tree species (Acer rubrum Marsh., Betula papyrifera Marsh., Fraxinus americana L ., Quercus rubra L., and Quercus velutina Lam.). In a greenhouse experiment, seedlings were subjected to combinations of shade, drought, and defoliation. We harvested seedlings over 32-97 days and measured biomass and NSC concentrations in stems and roots to estimate depletion rates. For all species and treatments, except for defoliation, seedling growth and NSC accumulation ceased. Shade and drought combined caused total NSC decreases in all species. For shade or drought alone, only some species experienced decreases. Starch followed similar patterns as total NSC, but soluble sugars increased under drought for drought-tolerant species. These results provide evidence that species deplete stored carbon in response to carbon limiting stress and that species differences in NSC response may be important for understanding carbon depletion as a buffer against shade- and drought-induced mortality.

  16. SUBSTRATE, LIME, PHOSPHORUS AND TOPDRESS FERTILIZATION IN MACAW PALM SEEDLING PRODUCTION

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    Leonardo Duarte Pimentel

    2016-04-01

    Full Text Available ABSTRACT The macaw palm [Acrocomia aculeata (Jacq. Lood. ex Mart] has been domesticated to subsidize biodiesel production programs in Brazil. However, little is known about the seedling production of this species. This study aimed to evaluate substrate mixtures, limestone and phosphorus rates for substrate amendment and topdressing frequency in macaw palm seedlings. Three trials were conducted in a greenhouse up to six months of nursery cultivation. Trial 1: determination of percent mineral and organic fractions of seven substrate mixtures. Trial 2: evaluation of four limerates for soil amendment versus four phosphorus rates. Trial 3: evaluation of N, K and Mg topdressing frequency. Significant differences were found in the three trials for most of the variables (plant height, leaf number, shoot dry mass, root dry mass, vigor and bulb diameter. The main results obtained were as follow: Trial1 - the best seedling growth was observed in substrates with at least 25% organic matter. Trial2 -lime rates ranging from 0.50 to 1.25 kg associated with 3 to 4 kg of single superphosphate per m3 of substrate provided the best seedling growth. Trial 3 - topdressing fertilization provided better development of seedlings regardless of frequency.

  17. Effects of rhizobacteria on the respiration and growth of Cerasus sachalinensis Kom. seedlings

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    Sijun Qin

    2016-06-01

    Full Text Available In this study, we investigated the influence of rhizosphere microorganisms on seed germination and root metabolism in Cerasus sachalinensis Kom. We inoculated C. sachalinensis plants with suspensions of dominant bacterial strains isolated from their rhizosphere. Four bacterial strains each with significant growth-promoting or growth-inhibiting effects were screened from the efficient root-colonizing microorganisms. The number of actinomycetes increased and that of fungi decreased significantly in the seedling rhizospheres after rhizobacteria treatment. The growth-promoting bacteria slightly affected the respiration rates and respiratory pathway enzymes, but significantly improved root viability, root carbohydrate concentration and seedling growth. Bacillus cereus, Staphylococcus sp. and Pseudomonas fluorescens were identified as the growth-promoting rhizobacteria; one strain could not be identified. After inoculation with the growth-inhibiting bacteria, the number of fungal colonies in the seedling rhizospheres increased and root viability and respiration rate as well as starch and sucrose accumulation in the roots significantly decreased. The glycolysis, pentose phosphate and alternative oxidase pathways became the major pathways of respiratory metabolism after inoculation with the growth-inhibiting bacteria. The height, leaf number, growth and dry weight of the seedlings decreased significantly in plants inoculated with the growth-inhibiting bacteria. Inoculation of C. sachalinensis rhizosphere with growth-promoting and growth-inhibiting bacteria affected the soil environmental factors such as microbial group composition, nutrient concentration and seedling biomass.

  18. Tolerance to Cadmium of Agave lechuguilla (Agavaceae Seeds and Seedlings from Sites Contaminated with Heavy Metals

    Directory of Open Access Journals (Sweden)

    Alejandra Méndez-Hurtado

    2013-01-01

    Full Text Available We investigated if seeds of Agave lechuguilla from contaminated sites with heavy metals were more tolerant to Cd ions than seeds from noncontaminated sites. Seeds from a highly contaminated site (Villa de la Paz and from a noncontaminated site (Villa de Zaragoza were evaluated. We tested the effect of Cd concentrations on several ecophysiological, morphological, genetical, and anatomical responses. Seed viability, seed germination, seedling biomass, and radicle length were higher for the non-polluted site than for the contaminated one. The leaves of seedlings from the contaminated place had more cadmium and showed peaks attributed to chemical functional groups such as amines, amides, carboxyl, and alkenes that tended to disappear due to increasing the concentration of cadmium than those from Villa de Zaragoza. Malformed cells in the parenchyma surrounding the vascular bundles were found in seedlings grown with Cd from both sites. The leaves from the contaminated place showed a higher metallothioneins expression in seedlings from the control group than that of seedlings at different Cd concentrations. Most of our results fitted into the hypothesis that plants from metal-contaminated places do not tolerate more pollution, because of the accumulative effect that cadmium might have on them.

  19. Tolerance to cadmium of Agave lechuguilla (Agavaceae) seeds and seedlings from sites contaminated with heavy metals.

    Science.gov (United States)

    Méndez-Hurtado, Alejandra; Rangel-Méndez, René; Yáñez-Espinosa, Laura; Flores, Joel

    2013-01-01

    We investigated if seeds of Agave lechuguilla from contaminated sites with heavy metals were more tolerant to Cd ions than seeds from noncontaminated sites. Seeds from a highly contaminated site (Villa de la Paz) and from a noncontaminated site (Villa de Zaragoza) were evaluated. We tested the effect of Cd concentrations on several ecophysiological, morphological, genetical, and anatomical responses. Seed viability, seed germination, seedling biomass, and radicle length were higher for the non-polluted site than for the contaminated one. The leaves of seedlings from the contaminated place had more cadmium and showed peaks attributed to chemical functional groups such as amines, amides, carboxyl, and alkenes that tended to disappear due to increasing the concentration of cadmium than those from Villa de Zaragoza. Malformed cells in the parenchyma surrounding the vascular bundles were found in seedlings grown with Cd from both sites. The leaves from the contaminated place showed a higher metallothioneins expression in seedlings from the control group than that of seedlings at different Cd concentrations. Most of our results fitted into the hypothesis that plants from metal-contaminated places do not tolerate more pollution, because of the accumulative effect that cadmium might have on them.

  20. Susceptibility of common alder (Alnus glutinosa) seeds and seedlings to Phytophthora alni and other Phytophthora species

    Energy Technology Data Exchange (ETDEWEB)

    Haque, M. M.; Diez, J. J.

    2012-11-01

    Phytophthora alni is a highly destructive host specific pathogen to alders (Alnus spp.) spreading all over Europe. Recently this pathogen has been reported to cause diseases in common alder (Alnus glutinosa) in Spain. Seeds and seedlings of A. glutinosa were tested in vitro for their susceptibility to alder Phytophthora and other Phytophthora species. Isolates of P. alni ssp. alni, P. cinnamomi, P. citrophthora, P. nicotianae and P. palmivora were used in the experiments. Seeds and seedlings were inoculated with a zoospore suspension and uniform mycelial blocks of agar of the Phytophthora species. Susceptibility was calculated in terms of pathogen virulence on seed germination and seedling mortality 42 and 67 days after inoculation respectively. Seed germination and seedling mortality rates varied differently among the isolates used. Results implied that common alder and its seeds and seedlings are at risk to be infected by P. alni. In addition, other Phytophthora species are able to infect this kind of material showing their relative host non-specificity. This is one important finding concerning alder regeneration in infected areas, and the possibility of disease spread on this plant material. (Author) 42 refs.

  1. Exploring the natural variation for seedling traits and their link with seed dimensions in tomato.

    Directory of Open Access Journals (Sweden)

    Noorullah Khan

    Full Text Available The success of germination, growth and final yield of every crop depends to a large extent on the quality of the seeds used to grow the crop. Seed quality is defined as the viability and vigor attribute of a seed that enables the emergence and establishment of normal seedlings under a wide range of environments. We attempt to dissect the mechanisms involved in the acquisition of seed quality, through a combined approach of physiology and genetics. To achieve this goal we explored the genetic variation found in a RIL population of Solanum lycopersicum (cv. Moneymaker x Solanum pimpinellifolium through extensive phenotyping of seed and seedling traits under both normal and nutrient stress conditions and root system architecture (RSA traits under optimal conditions. We have identified 62 major QTLs on 21 different positions for seed, seedling and RSA traits in this population. We identified QTLs that were common across both conditions, as well as specific to stress conditions. Most of the QTLs identified for seedling traits co-located with seed size and seed weight QTLs and the positive alleles were mostly contributed by the S. lycopersicum parent. Co-location of QTLs for different traits might suggest that the same locus has pleiotropic effects on multiple traits due to a common mechanistic basis. We show that seed weight has a strong effect on seedling vigor and these results are of great importance for the isolation of the corresponding genes and elucidation of the underlying mechanisms.

  2. Carbon and nitrogen gain during the growth of orchid seedlings in nature.

    Science.gov (United States)

    Stöckel, Marcus; Těšitelová, Tamara; Jersáková, Jana; Bidartondo, Martin I; Gebauer, Gerhard

    2014-04-01

    For germination and establishment, orchids depend on carbon (C) and nutrients supplied by mycorrhizal fungi. As adults, the majority of orchids then appear to become autotrophic. To compare the proportional C and nitrogen (N) gain from fungi in mycoheterotrophic seedlings and in adults, here we examined in the field C and N stable isotope compositions in seedlings and adults of orchids associated with ectomycorrhizal and saprotrophic fungi. Using a new highly sensitive approach, we measured the isotope compositions of seedlings and adults of four orchid species belonging to different functional groups: fully and partially mycoheterotrophic orchids associated with narrow or broad sets of ectomycorrhizal fungi, and two adult putatively autotrophic orchids associated exclusively with saprotrophic fungi. Seedlings of orchids associated with ectomycorrhizal fungi were enriched in (13) C and (15) N similarly to fully mycoheterotrophic adults. Seedlings of saprotroph-associated orchids were also enriched in (13) C and (15) N, but unexpectedly their enrichment was significantly lower, making them hardly distinguishable from their respective adult stages and neighbouring autotrophic plants. We conclude that partial mycoheterotrophy among saprotroph-associated orchids cannot be identified unequivocally based on C and N isotope compositions alone. Thus, partial mycoheterotrophy may be much more widely distributed among orchids than hitherto assumed.

  3. Seedling development and evaluation of genetic stability of cryopreserved Dendrobium hybrid mature seeds.

    Science.gov (United States)

    Galdiano, Renato Fernandes; de Macedo Lemos, Eliana Gertrudes; de Faria, Ricardo Tadeu; Vendrame, Wagner Aparecido

    2014-03-01

    Vitrification, a simple, fast, and recommended cryopreservation method for orchid germplasm conservation, was evaluated for Dendrobium hybrid "Dong Yai" mature seeds. The genetic stability of regenerated seedlings was also evaluated using flow cytometry. Mature seeds from this hybrid were submitted to plant vitrification solution (PVS2) for 0, 0.5, 1, 2, 3, 4, 5, or 6 h at 0 °C. Subsequently, they were plunged into liquid nitrogen (LN) at -196 °C for 1 h and recovered in half-strength Murashige and Skoog culture medium (1/2 MS), and seed germination was evaluated after 30 days. Seeds directly submitted to LN did not germinate after cryopreservation. Seeds treated with PVS2 between 1 and 3 h presented the best germination (between 51 and 58%), although longer exposure to PVS2 returned moderated germination (39%). Germinated seeds were further subcultured in P-723 culture medium and developed whole seedlings in vitro after 180 days, with no abnormal characteristics, diseases, or nutritional deficiencies. Seedlings were successfully acclimatized under greenhouse conditions with over 80% survival. Flow cytometry analysis revealed no chromosomal changes on vitrified seedlings, as well as seedlings germinated from the control treatment (direct exposure to LN). These findings indicate that vitrification is a feasible and safe germplasm cryopreservation method for commercial Dendrobium orchid hybrid conservation.

  4. Effect of seed mass on emergence and seedling development in Ptero-carpus marsupium Roxb

    Institute of Scientific and Technical Information of China (English)

    Yogeshwar Mishra; Rimi Rawat; P.K.Rana; M.K.Sonkar; Naseer Mohammad

    2014-01-01

    We investigated the effect of seed mass on emergence, seed-ling survival and growth of Pterocarpus marsupium Roxb., a medium to large, commercially valuable and deciduous tree species. Among the three size classes viz. small (10-12 mm), medium (13-15 mm) and large (16-17 mm), the maximum proportion of seed by number (54.12%) and dry weight (51.87%) was recorded in the medium size seed class. Seed length and seed width were greatest in the large seed class (16.50 mm, 7.33 mm) followed by medium (13.50 mm, 5.60 mm) and small (11.37 mm, 3.66 mm). Similarly, hundred seed weight (100 sw) varied from a maximum of 12.92 g in the large seed class to intermediate 10.95 g in the medium seed class and minimum of 7.02 g in the small seed class. The large seed size showed maximum emergence and shoot length over the medium and small seed class. After six months of growth, significant variations due to seed size were also observed for the growth and dry weight of P. marsupium seedlings. Seedling vigour, expressed in terms of height, collar diameter, number of leaves and dry biomass, was sig-nificantly affected by seed class. Seedlings that emerged from large seeds showed better growth and produced heavier seedlings as compared to medium and small seeds.

  5. Adaptation of Western Oak Seedlings to Yasuj Climate and Analysis of their Leaf Morphology

    Directory of Open Access Journals (Sweden)

    R. Zolfaghari

    2015-12-01

    Full Text Available Analysis of performance and survival rate of different oak species in severe climate of Zagros forests especially under global warming can help with management, conservation and restoration of these species. So, seeds of three oak species of Zagros (Quercus branti, Q. infectoria and Q. libani were collected from Baneh forests and sown in the common gardens of Yasuj. Then, their growth parameters such as collar diameter, height, trunk volume, height and collar increment, number of leaf and survival rate were measured and recorded during the growing season (June and October for the first two years. Also, in order to find a relationship between these traits and leaf morphological and qualitative traits of seedlings, some parameters like leaf area, specific leaf area, number of sprout and branch, bending of seedlings were measured and recorded. Results showed that at early growth age, seedlings of Q. branti and Q. infectoria had the largest and smallest size, respectively. Also, Q. libani seedlings showed a lower survival rate in the second year than other studied species due to the larger seeds. Results of correlation showed that seedlings with larger leaf area, higher number of branch and less straightness had higher growth and survival rate. It can be concluded that Q. infectoria is more susceptive to the increasing period and intensity of drought than other oaks of Zagros species.

  6. Effect of a longitudinally applied voltage upon the growth of Zea mays seedlings

    Science.gov (United States)

    Desrosiers, M. F.; Bandurski, R. S.

    1988-01-01

    The electrical parameters that affect young seedling growth were investigated. Voltages ranging from 5 to 40 volts were applied longitudinally along the mesocotyl region of 4-day old Zea mays L. (cv Silver Queen) seedlings for periods of 3 or 4 hours. It was determined that: (a) making the tips of the seedlings electrically positive relative to the base strongly inhibited shoot growth at 5 volts, whereas the reverse polarity had no effect; (b) at higher voltages, making the tip of the seedlings negative caused less growth inhibition than the reverse polarity at each voltage level; (c) the higher the applied voltage the greater the degree of inhibition; and, (d) the more growth inhibition experienced by the plants the poorer, and slower, their recovery. Previous observations of a relationship between the amount of free indole-3-acetic acid in the mesocotyl cortex and the growth rate of the mesocotyl and of gravitropism-induced movement of labeled indole-3-acetic acid from the seed to the shoot lead to the prediction of a voltage-dependent gating of the movement of indole-3-acetic acid from the stele to the cortex. This provided the basis for attempting to alter the growth rate of seedlings by means of an applied voltage.

  7. Production of Anadenanthera colubrine (Vell. Brenan seedlings using substrates based on composted sewage sludge

    Directory of Open Access Journals (Sweden)

    Maurício Bergamini Scheer

    2012-12-01

    Full Text Available The use of sewage sludge as raw material for forest growing is an alternative for the utilization and disposal of this solid waste. This work aimed at evaluating the use of a substrate based on composted sewage sludge and crushed pruning tree for the production of Anadenanthera colubrina seedlings (monjoleiro using three different fertilization levels. Seedling growth was then compared to growth on a commercial substrate based on composted Pinus bark and vermiculite. Three levels of fertilization (0; 2.7 and 4 g.dm-3 and three types of substrates were used: commercial substrate, and 3:1 (v:v or 2:1 (v:v composted substrate based on aerobic sewage sludge and crushed tree pruning. Seedling height, diameter and aerial dry mass (leaves and branches were measured. Considering seedlings growth without fertilization, the greatest values for all morphological characteristics were obtained using composted substrate based on sewage sludge. Growth rates in all treatments using 2.7 g.dm-3 of fertilizer, in many cases, can be considered sufficient, showing adequate amounts of nutrients to make up Anadenanthera colubrina seedling nutritional requirements and to promote adequate growth, with economy of the fertilizer.

  8. Comparative analysis of different methods for evaluating quality of Quercus ilex seedlings inoculated with Tuber melanosporum.

    Science.gov (United States)

    Andrés-Alpuente, Antonio; Sánchez, Sergio; Martín, María; Aguirre, Angel Javier; Barriuso, Juan J

    2014-04-01

    The quality of seedlings colonized by Tuber melanosporum is one of the main factors that contributes to the success or failure of a truffle crop. Truffle cultivation has quickly grown in European countries and elsewhere, so a commonly shared seedling evaluation method is needed. Five evaluation methods are currently published in the literature: three are used in Spain and two in France and Italy. Although all estimate the percentage colonization by T. melanosporum mycorrhizae, they do it in different ways. Two methods also estimate total number of mycorrhizae per seedling. Most are destructive. In this work, ten batches of holm oak seedlings inoculated with T. melanosporum from two different nurseries were evaluated by means of the five methods noted above. Some similarity was detected between the percentages of T. melanosporum mycorrhizae estimated by each method but not in their ability to assess the suitability of each batch. We discuss the advantages and disadvantages for each method and suggest approaches to reach consensus within the truffle culture industry for certifying mycorrhizal colonization by T. melanosporum and seedling quality.

  9. Have stump piles any effect on the pine weevil (Hylobius abietis L. incidence and seedling damage?

    Directory of Open Access Journals (Sweden)

    Abul Rahman

    2015-01-01

    Full Text Available Tree stumps are being increasingly used for bioenergy purposes, which may have significant effects on pine weevil (Hylobius abietis L. populations and the level of damage they can cause to seedlings. Pine weevils are attracted by the smell of fresh stumps in clear-cut areas, and have been shown to cause serious damage to planted coniferous seedlings in European forests. This study was conducted to measure the incidence of pine weevil and damage caused to Norway spruce (Picea abies seedlings in a field experiment including single stump pile plots (SSP, multiple stump pile plots (MSP and control plots in North Karelia, Finland. Pine weevils were significantly more abundant in MSP stump plots (22% higher than in SSP plots, and are 23% more abundant compared to the control plots. The extent of seedling damage was significantly lower in the SSP (by 67% and MSP plots (by 58% than in the controls. Seedlings damage increased significantly with the distance from the stump pile. Stump harvesting practices should be updated and, in particular, multiple stump piles should be avoided in the clearcut area. However, future studies will be required to explore the environmental and physical factors in the stump-removal area influencing pine weevil abundance.

  10. Root architecture simulation improves the inference from seedling root phenotyping towards mature root systems.

    Science.gov (United States)

    Zhao, Jiangsan; Bodner, Gernot; Rewald, Boris; Leitner, Daniel; Nagel, Kerstin A; Nakhforoosh, Alireza

    2017-02-01

    Root phenotyping provides trait information for plant breeding. A shortcoming of high-throughput root phenotyping is the limitation to seedling plants and failure to make inferences on mature root systems. We suggest root system architecture (RSA) models to predict mature root traits and overcome the inference problem. Sixteen pea genotypes were phenotyped in (i) seedling (Petri dishes) and (ii) mature (sand-filled columns) root phenotyping platforms. The RSA model RootBox was parameterized with seedling traits to simulate the fully developed root systems. Measured and modelled root length, first-order lateral number, and root distribution were compared to determine key traits for model-based prediction. No direct relationship in root traits (tap, lateral length, interbranch distance) was evident between phenotyping systems. RootBox significantly improved the inference over phenotyping platforms. Seedling plant tap and lateral root elongation rates and interbranch distance were sufficient model parameters to predict genotype ranking in total root length with an RSpearman of 0.83. Parameterization including uneven lateral spacing via a scaling function substantially improved the prediction of architectures underlying the differently sized root systems. We conclude that RSA models can solve the inference problem of seedling root phenotyping. RSA models should be included in the phenotyping pipeline to provide reliable information on mature root systems to breeding research. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  11. Plant growth-promoting rhizobacteria affect the growth and nutrient uptake of Fraxinus americana container seedlings.

    Science.gov (United States)

    Liu, Fangchun; Xing, Shangjun; Ma, Hailin; Du, Zhenyu; Ma, Bingyao

    2013-05-01

    Plant growth-promoting rhizobacteria (PGPR) are important catalysts that regulate the functional properties of agricultural systems. However, there is little information on the effect of PGPR inoculation on the growth and nutrient accumulation of forest container seedlings. This study determined the effects of a growth medium inoculated with PGPR on the nutrient uptake, nutrient accumulation, and growth of Fraxinus americana container seedlings. PGPR inoculation with fertilizer increased the dry matter accumulation of the F. americana aerial parts with delayed seedling emergence time. Under fertilized conditions, the accumulation time of phosphorous (P) and potassium (K) in the F. americana aerial parts was 13 days longer due to PGPR inoculation. PGPR increased the maximum daily P and K accumulations in fertilized seedlings by 9.31 and 10.44 %, respectively, but had little impact on unfertilized ones. Regardless of fertilizer application, the root exudates, namely sugars, amino acids, and organic acids significantly increased because of PGPR inoculation. PGPR inoculation with fertilizer increased the root, shoot, and leaf yields by 19.65, 22.94, and 19.44 %, respectively, as well as the P and K contents by 8.33 and 10.60 %, respectively. Consequently, the N, P, and K uptakes increased by 19.85, 31.97, and 33.95 %, respectively. Hence, PGPR inoculation with fertilizer can be used as a bioenhancer for plant growth and nutrient uptake in forest container seedling nurseries.

  12. Combined effects of lead and acid rain on photosynthesis in soybean seedlings.

    Science.gov (United States)

    Hu, Huiqing; Wang, Lihong; Liao, Chenyu; Fan, Caixia; Zhou, Qing; Huang, Xiaohua

    2014-10-01

    To explore how lead (Pb) and acid rain simultaneously affect plants, the combined effects of Pb and acid rain on the chlorophyll content, chlorophyll fluorescence reaction, Hill reaction rate, and Mg(2+)-ATPase activity in soybean seedlings were investigated. The results indicated that, when soybean seedlings were treated with Pb or acid rain alone, the chlorophyll content, Hill reaction rate, Mg(2+)-ATPase activity, and maximal photochemical efficiency (F(v)/F(m)) were decreased, while the initial fluorescence (F 0) and maximum quantum yield (Y) were increased, compared with those of the control. The combined treatment with Pb and acid rain decreased the chlorophyll content, Hill reaction rate, Mg(2+)-ATPase activity, F(v)/F(m), and Y and increased F 0 in soybean seedlings. Under the combined treatment with Pb and acid rain, the two factors showed additive effects on the chlorophyll content in soybean seedlings and exhibited antagonistic effects on the Hill reaction rate. Under the combined treatment with high-concentration Pb and acid rain, the two factors exhibited synergistic effects on the Mg(2+)-ATPase activity, F 0, F v/F m, as well as Y. In summary, the inhibition of the photosynthetic process is an important physiological basis for the simultaneous actions of Pb and acid rain in soybean seedlings.

  13. Growth and survival response of potted Cupressus sempervirens seedlings to different soils.

    Science.gov (United States)

    Tabari, Masoud; Saeidi, Hamid Reza; Alavi-Panah, Kazem; Basiri, Reza; Poormadjidian, Mohammad Reza

    2007-04-15

    In February 2001, one-year bareroot cypress (Cupressus sempervirens var. horizontalis) seedlings were replanted in plastic pot in a lowland nursery located in southern coast of the Caspian Sea (north of Iran). Soils of pots consisted of 1:1 sand:clay (A), pure sand (B), 2:1 sand:clay (C), 1:1:1 sand:clay:organic matter (D), 1:1:2 sand:clay:organic matter (E). In each soil treatment a high value of survival and growth was appeared in July and progressively decreased till November. In each month the seedlings grown on rich soils (D and E) had mostly greater growth and survival than on infertile soils. At the end of the first growing season seedling vitality differed significantly among the soils but did not differed notably in soil A with those in other soils. Survival rate was highest in the rich soils (D and E). Stem length as well as collar diameter performed the least growth on the poor soils (B and C). Like other characteristics measured, survival responded better to soils containing organic matter (D and E). It is concluded that generally characteristics of cypress seedling are suited by adding organic matter to sandy soils. This is while that poor nutrient available soil such as soil A produces a proper growth for cypress seedling, too.

  14. Warming and neighbor removal affect white spruce seedling growth differently above and below treeline.

    Science.gov (United States)

    Okano, Kyoko; Bret-Harte, M Syndonia

    2015-01-01

    Climate change is expected to be pronounced towards higher latitudes and altitudes. Warming triggers treeline and vegetation shifts, which may aggravate interspecific competition and affect biodiversity. This research tested the effects of a warming climate, habitat type, and neighboring plant competition on the establishment and growth of white spruce (Picea glauca (Moench) Voss) seedlings in a subarctic mountain region. P. glauca seedlings were planted in June 2010 under 4 different treatments (high/control temperatures, with/without competition) in 3 habitats (alpine ridge above treeline/tundra near treeline /forest below treeline habitats). After two growing seasons in 2011, growth, photosynthesis and foliar C and N data were obtained from a total of 156, one-and-a-half year old seedlings that had survived. Elevated temperatures increased growth and photosynthetic rates above and near treeline, but decreased them below treeline. Competition was increased by elevated temperatures in all habitat types. Our results suggest that increasing temperatures will have positive effects on the growth of P. glauca seedlings at the locations where P. glauca is expected to expand its habitat, but increasing temperatures may have negative effects on seedlings growing in mature forests. Due to interspecific competition, possibly belowground competition, the upslope expansion of treelines may not be as fast in the future as it was the last fifty years.

  15. Biomass and nutrients allocation in pot cultured beech seedlings:influence of nitrogen fertilizer

    Institute of Scientific and Technical Information of China (English)

    Ali Bagherzadeh; Rainer Brumme; Friedrich Beese

    2008-01-01

    Allocation of biomass and nutrient elements including Nitrogen to above and belowground compartments of beech seedlings (Fagus sylvatica L.) treated by labeled nitrogen fertilizer in the form of 15NH4 and 15NO3 were investigated at the end of two successive growing seasons.Pot cultured beech seedlings were grown at a green house on intact soil cores sampled from three adjacent stands including beech,Norway spruce and mixed beech-spruce cultures of Solling forest,Germany.Comparing biomass allocation and nutrients concentrations of the seedlings between the control and 15N-fertilized treatments revealed no significant effect of N fertilization on nutrients uptake by seedlings over the experiment.The form of N input influenced its movement into plant pools.It was demonstrated that beech seedlings take up nitrogen mainly in the form of nitrate,which is then reduced in the leaves,although the differences between the retention of NO3 ̄-N and NH4+-N in plants were not statistically significant.Percent recoveries of 15N in trees were typically greater after 15NO3 than after 15NH4 additions.It was indicated that immobilization of 15N tracer in fine roots was a slower process comparing other plant compartments such as stem and coarse roots,but a powerful sink for N during the course of study.

  16. Water Relation Parameters of Embryogenic Cultures and Seedlings of Larch

    Science.gov (United States)

    Livingston, Nigel J.; von Aderkas, Patrick; Fuchs, Edgar E.; Reaney, Martin J. T.

    1992-01-01

    Changes in the water relations parameters of developing somatic embryogenic and xygotic European larch (Larix decidua) were studied. Water release curves were generated by suspending tissue samples over unsaturated NaCl solutions until they reached vapor equilibration with the surrounding air. Twenty solutions were used whose water potentials ranged from −0.05 to −10 MPa. Water release curves were obtained by plotting paired values of tissue relative water content (RWC) and solution potential. Curves were derived for embryonic larch at various stages of development and for hypocotyls and roots from germinated zygotic and somatic embryos. The ability to resist dehydration increased markedly with development. Stage 1 tissue, which consisted of clusters of loosely associated nonchlorophyllous cells, had extremely low bulk elastic modulus (ε) (1.91 MPa) and apoplastic water content (A) (0.023), relatively high osmotic potential (Ψπ) (−0.53 MPa), and lost turgor at 0.56 RWC. In contrast, mature embryoids with primary roots, hypocotyl, and cotyledons (stage 3) had an almost 4-fold increase in A (0.089), significantly higher ε (3.49 MPa), and lower Ψπ (−0.88 MPa) and lost turgor at 0.66 RWC. Hypocotyl tissue from germinated somatic embryos lost turgor at 0.74 RWC and had higher ε, A, and solute accumulation than pregerminated tissue. Hypocotyl tissue resisted dehydration more strongly than root tissue, and differences between root and hypocotyl water relation parameters were more pronounced in xygotic than in somatic seedlings. Highest dehydration resistance was in zygotic hypocotyls. The characterization of the water relations of tissue cultures should allow the development of more consistent and reliable desiccation protocols to induce maturation of embryos and produce synchronously germinating seed. PMID:16653121

  17. Low power continuous wave-laser seed irradiation effect on Moringa oleifera germination, seedling growth and biochemical attributes.

    Science.gov (United States)

    Urva; Shafique, Hina; Jamil, Yasir; Haq, Zia Ul; Mujahid, Tamveel; Khan, Aman Ullah; Iqbal, Munawar; Abbas, Mazhar

    2017-05-01

    Recently, laser application in agriculture has gained much attention since plant characteristics were improved significantly in response of pre-sowing seed treatment. Pre-sowing laser seed treatment effects on germination, seedling growth and mineral profile were studied in Moringa olifera. M. olifera healthy seeds were exposed to 25, 50, 75mJ low power continuous wave laser light and grown under greenhouse conditions. The seedling growth and biochemical attributes were evaluated from 10-day-old seedlings. The germination parameters (percentage, mean germination time), vigor index, seedling growth (root length, seedling length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight) enhanced considerably. The laser energy levels used for seed irradiation showed variable effects on germination, seedling growth and mineral profile. The mineral contents were recorded to be higher in seedling raised from laser treated seeds, which were higher in roots versus shoots and leaves. The effect of laser treatment on seedling fat, nitrogen and protein content was insignificant and at higher energy level both nitrogen and protein contents decreased versus control. Results revealed that M. olifera germination, seedling growth and mineral contents were enhanced and optimum laser energy level has more acceleratory effect since at three laser energy levels the responses were significantly different. Overall the laser energy levels effect on germination and seedling growth was found in following order; 75mJ>50mJ>25mJ, where as in case of fat, protein and nitrogen contents the trend was as; 25mJ>50mJ and 75mJ. However, this technique could possibly be used to improve the M. olifera germination, seedling growth, and minerals contents where germination is low due to unfavorable conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Difference of Low Temperature and Low Irradiance-Resistance between Figleaf Gourd and Cucumber Seedlings Related to Mineral Elements Uptake

    Institute of Scientific and Technical Information of China (English)

    LI Jian-Yong; GUO Shang-Jing; LI Xin-Guo; MENG Jing-Jinga; HE Qi-Wei

    2009-01-01

    We have repotted that the roots of fig, leaf gourd (Cucurbita ficifolia, as rootstock) could improve the resistance of cucumber seedlings (Cucumis sativus L.cv. Jinyan 4, as scion) to 6 h stress at low temperature and low irradiance [1]. In this experiment, the relationship between the mineral elements uptake and photosynthetic activity of photosystems in figleaf gourd and cucumber seedlings were to be studied during low temperature (8 C) stress under low irradiance (100 μ. mol m-2 s-1 PFD) for 5 days. Compared with control seedlings, the maximal photochemical efficiency of PS2 (Fv/Fm) and the oxidizable P700 (P700+) of both figleaf gourd and cucumber seedlings decreased, and beth Fv/Fm and P700+ were lower in cucumber leaves than in figleaf gourd seedlings at the end of the stress. Superoxide dismutase (SOD) activity was higher in beth leaves and roots of figleaf gourd than in leaves and roots of cucumber at both room temperature and low temperature. However, the product rate of O 2 was lower in figleaf gourd leaves than in cucumber leaves. Upon ex-posure to the stress, the malondialdehyde (MDA) content increased markedly in leaves and roots of figleaf gourd and cucumber seedlings, and it grew faster in cucumber seedlings than that in figleaf gourd seedlings. Under adaptive conditions, some mineral elements (Such as Cu, Zn, Mn and Mg) have different contents in leaves and roots between figleaf gourd seedlings and cucumber seedlings. However, at the end of the stress these elements were accumulated apparently in both leaves and roots of figleaf gourd accompanied by no obvious change in cucumber seedlings.

  19. Evaluation of essential oils in health and physiological quality of Schinus molle seeds and seedlings

    Directory of Open Access Journals (Sweden)

    Kamila Cardoso Pereira

    2016-03-01

    Full Text Available The objective was to evaluate the effect of Mentha piperita, Cymbopogon nardus and Eucalyptus globules essential oils, in sanitary and physiological quality of Schinus molle L. seeds and seedlings. The seeds were treated with essential oils at concentrations of 10%, on 1 μL g-1, 20%, on 2 μL g-1, 30% , on 3 μL g-1 and control. After treatments, seeds were evaluated by sanity test, using filter paper method (“blotter test” and by germination test, where the seeds were placed between vermiculite substrate. For counts, sprouted and dead seeds were considered. Shoot length, root, total height and stem diameter were measured for seedlings evaluation. The use of citronella and mint essential oils reduced the incidence of different pathogens in S. molle seeds. Mint essential oil at 20% and 30% were effective to promote seeds germination. Eucalyptus essential oil in any concentration was efficient to increase seedlings growth.

  20. Studies on Tomato Seedling Quality Indices Under Simulated Shipping and Storage Conditions

    Institute of Scientific and Technical Information of China (English)

    NING Wei; GE Xiao-guang; LI Tian-lai

    2004-01-01

    Indices of the tomato seedling quality maintenance level after production before field planting were studied through simulated experiments, small--scale operation, indoor analyses and measurements, and field observation. The results showed that under simulated shipping and storage conditions, seedling quality change following different durations (days) of shipping and storage was correlated significantly or even very significantly with certain physiological and morphological indices. With various measured indices following different periods of shipping and storage treatment subjected to multinomial successive regressive correlation analysis, the principal factors influencing seedling quality maintenance level are identified to be chlorophyll content→dry short weight→ leaf freshness index in order of their importance. Significance analysis with multinomial fitted equation indicated that correlations between any one of above three factors and the growth index after field planting reached very significant difference level.

  1. Modelling changes in leaf shape prior to phyllode acquisition in Acacia mangium Willd. seedlings.

    Science.gov (United States)

    Leroy, Céline; Heuret, Patrick

    2008-02-01

    The aim of this study was to characterise changes in leaf shape prior to phyllode acquisition along the axes of Acacia mangium seedlings. The study area was located in North Lampung (South Sumatra, Indonesia), where these trees belong to a naturally regenerated stand. A total of 173 seedlings, less than three months old, were described node by node. Leaf shape and leaf length were recorded and the way in which one leaf type succeeded another was modelled using a hidden semi-Markov chain composed of seven states. The phyllotactical pattern was studied using another sample of forty 6-month-old seedlings. The results indicate (i) the existence of successive zones characterised by one or a combination of leaf types, and (ii) that phyllode acquisition seems to be accompanied by a change in the phyllotactical pattern. The concepts of juvenility and heteroblasty, as well as potential applications for taxonomy are discussed.

  2. Relationships between xanthoxin, phototropism, and elongation growth in the sunflower seedling Helianthus annuus L.

    Science.gov (United States)

    Franssen, J M; Bruinsma, J

    1981-04-01

    For phototropic curvature of a green sunflower seedling, only the hypocotyl has to be illuminated; the tip and cotyledons are not involved in stimulus perception. The etiolated seedling is phototropically insensitive, illumination of only the hypocotyl renders it sensitive. It is concluded that the photoreceptor is located within the responding organ. In curving seedlings, the endogenous indoleacetic acid (IAA) remains evenly distributed. However, the inhibitor, xanthoxin (Xa), accumulates on the illuminated side. The degree of phototropic response is generally related to the concentration of Xa. The amount of phototropic curvature is independent of the rate of elongation growth, the former can be changed without affecting the latter, and vice versa. The data conflict with the Cholodny-Went theory, whereas they support the hypothesis of Blaauw that the phototropic reaction is caused by the local accumulation of a growth-inhibiting substance on the irradiated side.

  3. Mucilage extraction and substrates in the seedling development of yellow passion fruit plants

    Directory of Open Access Journals (Sweden)

    Ricardo Sfeir Aguiar

    2014-02-01

    Full Text Available The object of this work was to evaluate different methods of mucilage extraction and substrates on passion fruit seedling emergence and development , in a mist chamber. Five methods of mucilage extraction were used: water, water + sand, water + virgin whitewash; blender with protected blades and fermentation in water, and three different types of substrates: rice hull, vermiculite and coconut fiber. The experiment had a completely randomized design with five replications in a factorial 5 x 3 scheme (5 extraction methods of seed mucilage and 3 substrates being each parcel composed of 25 seeds. The parameters evaluated were: seedling emergence, speed of emergence index, leaf number, stem length, longest root length, weight of dry matter of roots and shoots. Water and fermentation in water are the best method for mucilage extraction and rice hull and coconut fiber are the best substrate for passionfruit seedling emergence and development.

  4. Sowing on the emergence and early development of seedlings o baru

    Directory of Open Access Journals (Sweden)

    Alan Mario Zuffo

    2014-09-01

    Full Text Available The objective of this work to evaluate the influence of the position of baru seeds, the emergence and early seedling development. The test was conducted in a greenhouse experiment in randomized blocks, with five treatments (seeding position, with four replications, positions were: A - Hilo up, B - hilo down C - hilum and raphe aside, D - horizontal raphe up, E - horizontal raphe down. It was observed that the seeds deposited at the position B (heel down provided better emergence and seedling development. We evaluated the emergence, speed of emergence index, plant height, stem diameter, root length, dry mass of air, root dry weight, relative AP/DC, FSPA/FSR and Dickson quality index. The emergence and early seedling development baru were influenced by sowing position. The seeds deposited with the hilum down provided better results.

  5. Phytotoxicity of zinc and manganese to seedlings grown in soil contaminated by zinc smelting

    Science.gov (United States)

    Beyer, W.N.; Green, C.E.; Beyer, M.; Chaney, R.L.

    2013-01-01

    Historic emissions from two zinc smelters have injured the forest on Blue Mountain near Palmerton, Pennsylvania, USA. Seedlings of soybeans and five tree species were grown in a greenhouse in a series of mixtures of smelter-contaminated and reference soils and then phytotoxic thresholds were calculated. As little as 10% Palmerton soil mixed with reference soil killed or greatly stunted seedlings of most species. Zinc was the principal cause of the phytotoxicity to the tree seedlings, although Mn and Cd may also have been phytotoxic in the most contaminated soil mixtures. Calcium deficiency seemed to play a role in the observed phytotoxicity. Exposed soybeans showed symptoms of Mn toxicity. A test of the effect of liming on remediation of the Zn and Mn phytotoxicity caused a striking decrease in Sr-nitrate extractable metals in soils and demonstrated that liming was critical to remediation and restoration.

  6. Seed Priming Effect on Germination, Seedling Growth and Salt Tolerance of Loquat (Eriobotrya japonica Lindl.

    Directory of Open Access Journals (Sweden)

    FATEMEH SADEGHI

    2015-12-01

    Full Text Available The improvement of loquat seed germination, seedling growth was investigated using seed priming technique. The experiment was conducted in completely random design with 3 replications and 24 seeds in each replication. Treatments were different solutions of sodium chloride and potassium nitrate with electrical conductivity of 0, 4, 8, 12 and dS m-1. The results showed that the highest germination percentage (83% gained in 8 dS m-1 NaCl solution. The NaCl primed seeds showed higher stem length, root and shoot dry weight than control. The primid seedlings were transferred into a closed hydro culture system containing different level of salinity to assisset their salt tolerance. The activities of superoxide dismutase, peroxidase, and ascorbite peroxidase were enhanced in salt-stressed condition. Pre-treated seedlings had also higher proline content than control.

  7. TENACITY AND PERSISTENCE OF COPPER FUNGICIDES IN CITRUS SEEDLINGS UNDER SIMULATED RAINFALL

    Directory of Open Access Journals (Sweden)

    ANTONIO EDUARDO FONSECA

    2016-01-01

    Full Text Available The amount of fungicide that adheres to the leaf during spraying and the amount that remain on the leaf after weathering are the main factors that defines the amount of active residue on the leaf surface to effectively control plant pathogens. Thus, the objective of this work was to evaluate the tenacity and persistence of copper in citrus seedling leaves under simulated rainfall in Jaboticabal, State of São Paulo, Brazil. The evaluated variables were copper content, solution retention, surface tension and drop spectrum. A significant and inversely proportional linear relationship to drops <100 μm was found. The percentage of copper retained in leaves of citrus seedlings with copper fungicides of suspension concentrate (SC formulations after simulated rainfall was greater than 80%. Copper fungicides of SC formulations presented the lowest surface tension, allowing greater tenacity and persistence of copper on seedlings of citrus leaves after simulated rainfall and increased contact between the drops and leaf surface.

  8. Purification and characterization of acid phosphatase from a germinating black gram (Vigna mungo L. seedling

    Directory of Open Access Journals (Sweden)

    Asaduzzaman A.K.M.

    2011-01-01

    Full Text Available An acid phosphatase has been isolated and purified from an extract of a germinating black gram seedling. The method was accomplished by gel filtration of a germinating black gram seedling crude extract on sephadex G-75 followed by ion exchange chromatography on DEAE cellulose. The acid phosphatase gave a single band on SDS-polyacrylamide slab gel electrophoresis. The molecular weight of the acid phosphatase determined by SDS-polyacrylamide slab gel electrophoresis was estimated to be 25 kDa. The purified enzyme showed maximum activity at pH 5 and at temperature of 55°C. Mg2+, Zn2+ and EDTA had an inhibitory effect on the activity of the acid phosphatase. Black gram seedling acid phosphatase was activated by K+, Cu2+ and Ba2+. The Km value of the enzyme was found to be 0.49 mM for pNPP as substrate.

  9. Ferulic acid depletion by cultured soybean seedlings under action of glucose and methionine

    Directory of Open Access Journals (Sweden)

    Herrig Vanessa

    2000-01-01

    Full Text Available Cultured soybean seedlings were used to investigate how glucose or methionine influenced depletion of ferulic acid. Three-day-old seedlings were grown in hydroponic solution containing ferulic acid plus glucose or methionine, and the level of the phenolic acid were monitored in the nutrient culture. The results showed that ferulic acid depletion was more rapid in the presence of those compounds. After 6 h, the increase caused by glucose (0.01 and 0.05 mM was more pronounced than methionine in the same concentrations. On the other hand, methionine (0.1 and 0.2 mM increased depletion more significantly than glucose. Results suggested that both compounds might to increase the allelopathic effects of ferulic acid in the seedlings.

  10. Effect of saline water irrigation on seed germination and early seedling growth of the halophyte quinoa

    DEFF Research Database (Denmark)

    Panuccio, M.R.; Jacobsen, Sven-Erik; Saleem Akhtar, Saqib;

    2014-01-01

    been carried out to investigate the mechanisms used by quinoa, a facultative halophytic species, in order to cope with high salt levels at various stages of its develop- ment. Quinoa is regarded as one of the crops that might sustain food security in this century, grown primarily for its edible seeds...... of SW and different salts on seed germination, seedling emergence and the antioxidative pathway of quinoa. Seeds were germi- nated in Petri dishes and seedlings grown in pots with SW solutions (25, 50, 75 and 100 %) and NaCl, CaCl2, KCl and MgCl2 individually, at the concentrations in which...... parameters affected were root and shoot length, root morphology, fresh and dry weight, and water content. An efficient antioxidant mechanism was present in quinoa, activated by salts during germination and early seedling growth, as shown by the activities of antioxidant enzymes. Total antioxidant capacity...

  11. Survival and growth of eucalypts clones seedlings in response to organic fertilizer application

    Directory of Open Access Journals (Sweden)

    Sula Janaína de Oliveira Fernandes

    2011-12-01

    Full Text Available This work aimed to evaluate the effect of Fert-Bokashi® on survival and seedlings growth of two Eucalyptus urophylla clones propagated by minicutting technique. The experiment was conducted over a period of 28 days using a randomized block design and three replicates in an 6 x 2 factorial arrangement, with six Fert-Bokashi® concentrations (0.0%, 0.1%, 0.3%, 0.5%, 0.7% and 0.9% and two clones. Seedlings survival, height growth and shoot, root and total dry matter were evaluated. Experimental results demonstrated no significant effect of Fert- Bokashi® on survival and seedlings growth of two Eucalyptus urophylla clones.

  12. [Effects of light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut seedling leaves].

    Science.gov (United States)

    Yan, Meng-Meng; Wang, Ming-Lun; Wang, Hong-Bo; Wang, Yue-Fu; Zhao, Chang-Xing

    2014-02-01

    This study explored the effects of different light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut (Qinhua 6) seedling leaves. The results showed that, compared with natural light, blue light (445-470 nm) could significantly improve the specific leaf area (SLA), chlorophyll a/b value and carotenoid content of peanut seedlings. Meanwhile, the net photosynthetic rate, stomatal conductance, and transpiration rate were higher, the intercellular CO2 content was lower, and the photosynthetic efficiency was improved significantly under blue light. Red light (610-660 nm) could improve the chlorophyll content significantly, and reduce SLA, chlorophyll a/b value and carotenoid content, with a lower photosynthetic efficiency than natural light. Green light (515-520 nm) and yellow light (590-595 nm) were not conducive to photosynthetic pigment accumulation of leaves, and significantly inhibited leaf photosynthesis of peanut seedlings.

  13. GROWTH AND NODULATION OF LEUCAENA AND PROSOPIS SEEDLINGS IN SOIL PLUS TANNERY SLUDGE

    Directory of Open Access Journals (Sweden)

    Ademir Sérgio Ferreira de Araújo

    2006-01-01

    Full Text Available The objective of this paper was to evaluate the growth and nodulation of Leucaena and Prosopis seedlings in soil plus tannery sludge. The study was conducted in a greenhouse, using bags containing soil plus tannery sludge. Seedlings of Leucaena and Prosopis inoculated with Bradyrhizobium sp were used. Results were evaluated 90 days after plant emergency. The application of tannery sludge, in the rate of 11.250 kg per hectare significantly increased plant height, stem diameter, and above ground dry mass ofLeucaena. Regarding Prosopis, there were no significant increases in these variables with tannery sludge application, except for aerial dry mass. No significant differences were seen between the treatments with sludge and inoculated with Bradyrhizobium sp. as to nodule number and dry mass. Tannery sludge evaluated in this work did not affect nodulation, besides favoring Leucaena and Prosopis seedling growth.

  14. Germination and seedling growth of Okra (Abelmoschus esculentus L. as influenced by organic amendments

    Directory of Open Access Journals (Sweden)

    Banashree Sarma

    2015-12-01

    Full Text Available This study was designed to understand the effects of different soil organic amendments on germination and seedling vigour of Okra (Abelmoschus esculentus L.. Five treatments with organic amendments (farmyard manure, vermicompost and biochar and mineral fertilizers were designed in randomized block design with three replications. Results showed that organic amendments significantly enhanced per cent seed germination and emergence speed index compared to inorganic fertilizer. Highest homogeneity of seed germination (CVgt = 20.74 was observed in vermicompost. Plant height, root length and leaf area were higher in vermicompost and biochar than farmyard manure. Both allocation of biomass to above ground parts and Dickson quality index were highest in seedlings from the plots amended with vermicompost. The study revealed that compared to biochar, vermicompost and farmyard manure significantly enhanced the germination and growth of Okra seedling, but the stimulation was best in vermicompost-amended plots.

  15. Effect of SO/sub 2/ on stomatal aperture and sulfur uptake of woody angiosperm seedlings

    Energy Technology Data Exchange (ETDEWEB)

    Noland, T.L.; Kozlowski, T.T.

    1979-01-01

    Effects of SO/sub 2/ pollution on stomatal aperture and sulfur uptake varied with SO/sub 2/ dosage and plant species. Fumigation of Ulmus americana L. seedlings with 1 ppm SO/sub 2/ for 8 h inhibited stomatal closure and fumigation with 2 ppm SO/sub 2/ for 12 h induced stomatal closure. Sulfur uptake of fumigated Ulmus americana seedlings depended on stomatal aperture and was much higher in the light than in the dark. Fumigation of water-stressed Ginkgo biloba L. seedlings with 2 ppm SO/sub 2/ for 6.5 h tended to prevent stomatal closure. However, the effects of SO/sub 2/ on stomatal aperture were modulated and often overridden by environmental stresses such as low light intensity and drought.

  16. Soil Type Affects Pinus ponderosa var. scopulorum (Pinaceae Seedling Growth in Simulated Drought Experiments

    Directory of Open Access Journals (Sweden)

    Alexander J. Lindsey

    2013-07-01

    Full Text Available Premise of the study: Effects of drought stress and media type interactions on growth of Pinus ponderosa var. scopulorum germinants were investigated. Methods and Results: Soil properties and growth responses under drought were compared across four growth media types: two native soils (dolomitic limestone and granite, a soil-less industry standard conifer medium, and a custom-mixed conifer medium. After 35 d of growth, the seedlings under drought stress (reduced watering produced less shoot and root biomass than watered control seedlings. Organic media led to decreased root biomass, but increased root length and shoot biomass relative to the mineral soils. Conclusions: Media type affected root-to-shoot biomass partitioning of P. ponderosa var. scopulorum, which may influence net photosynthetic rates, growth, and long-term seedling survival. Further work should examine how specific soil properties like bulk density and organic matter influence biomass allocation in greenhouse studies.

  17. Seedling stage strategies as a means of habitat specialization in herbaceous plants

    DEFF Research Database (Denmark)

    ten Brink, Dirk-Jan; Bruun, Hans Henrik

    2011-01-01

    specialized to forest vs. open habitats and to dry vs. wet habitats. We also tested whether effects of shade and drought vary independently or, alternatively, if shade may amplify effects on drought-stressed plants. Seedling response in terms of growth rate, height, slenderness, specific leaf area (SLA...... for the moist-habitat species, for which elongation increased with shade. Contrary to our expectations, species from dry habitats grew bigger than species from moist habitats in all treatments. SLA responded to the light treatment, but not to watering regime. The contrasting light and moisture conditions across...... habitats appear to not have selected for differences in SLA. We conclude that seedling phase strategies of resource allocation in temperate herbs contribute to their habitat specialization. Habitat-specific seedling strategies and trade-offs in response to resource availability and environmental conditions...

  18. Samara size versus dispersal and seedling establishment in Ailanthus altissima (Miller) Swingle.

    Science.gov (United States)

    Delgado, J A; Jimenez, M D; Gomez, A

    2009-03-01

    We have specifically carried out a greenhouse experiment to assess relationship between samara weight and seed success. Relationship assessed as dispersal potential, germination level, germination rate and early seedling mass for the invasive species Ailanthus altissima. For this purpose, we considered two close stands as seeds source. We found no correlation between samara size and neither germination level, germination rate, nor seedling mass, but a positive correlation with samara projected area. These results suggest that samara weight is not directly related to germination, dispersal and invasion potential neither. Nevertheless, stands differed in the invasion potential of their samaras; one stand presented samaras with higher projected area per weight unit whereas the other one presented samaras that produced heavier seedlings. Whatever the origin, (genetic or environmental) of this differences it should be advantageous for a colonizing invader species such as A. altissima since it could imply a wider range of habitats susceptible to invasion.

  19. Fertirrigation in production of seedlings of Eucalyptus grandis during winter and summer

    Directory of Open Access Journals (Sweden)

    Simone Fernandes Ciavatta

    2014-04-01

    Full Text Available Studies correlating the splitting of fertigation with the development and quality of tree seedlings in different production systems and periods of the year are fundamental to optimize inputs and minimization of the production cycle. Thus we conducted this study aimed to check the influence of the split of fertigation in the development and quality of Eucalyptus grandis seedlings in winter and summer periods. The fertilization through the irrigation system by capillarity was split on: one, two, three or six times in the week, maintaining the total amount of nutrients applied. We concluded that the most effective fertigation for the development and quality of seedlings of Eucalyptus grandis were six and one times in the week for the period of winter and summer, respectively, demonstrating the need for adequacy of fertigation managements according to the period of year.

  20. The growth of maize seedlings as function of free energy and redox potential

    Directory of Open Access Journals (Sweden)

    Dragičević Vesna D.

    2010-01-01

    Full Text Available The difference in the growth of maize seedlings originating from seeds injured by accelerated ageing, as well as those altered by restoring with low 2,4-D (2,4-dichlorophenoxyacetic acid concentrations was examined, from the point of view of free energy and redox potential. The ageing decreased germination ability, the seedling growth and free energy, with no remarkable influence on the redox capacity. Meanwhile, the 2,4-D treatment increased the germination percentage and the seedling growth, by better energy utilisation, with shifting of the redox balance to a reducing environment. From this point of view, the free energy and the redox potential are useful tools for the determination of biological vitality.