Effects of Temperature, Light and Pre-Chilling on Seed Germination of Stevia rebaudiana (Bertoni Bertoni Accessions

Directory of Open Access Journals (Sweden)

Mario Macchia

Full Text Available Stevia rebaudiana (Bertoni Bertoni is a perennial shrub of the Asteraceae family native to Paraguay and Brazil where it has been used for several years as a sweetener. It is a short-day species, with a critical light requirement for flowering of roughly 13 hours. In plants whose biological cycle is strongly photoperiod-dependent, latitude is one of the major factors influencing reproduction. Late flowering may adversely affect seed production if this occurs during a season that is unfavorable to pollination. At Italian latitudes, this species often gives scanty seed production, with low germination rate and poor germination energy of seeds produced. In 2001 four accessions have been grown for seed production in a field plot experiment in Central Italy. The various accessions were found to exhibit noticeably different photoperiod requirements, which affected flowering time (from late August to the end of September and consequently also the conditions of achene filling and ripening. Late flowering and seed ripening occurred during autumn season, unfavourable to complete seed formation, leading to an increase in the empty seed percentage recorded for each accession. Detailed germination trials were therefore undertaken using seeds collected from plants of the different accessions in order to assess the quality of the seeds produced. Various germination methods have been tested in a controlled environment adopting four different temperatures (20° C, 25° C constant temperature and 15/25° C, 20/30° C (16/8h alternating temperature in light or darkness with or without pre-chilling. Germination rates varied over an extensive range (germination percentage from 9 to 83%, mainly due to the divergent specific characteristics of the material examined and the different treatments studied. At all temperatures tested, the most earlier accession, showed the higher germination percentages (54-83% while the latest accession was among those with the lowest

Mapping QTL for Seed Germinability under Low Temperature Using a New High-Density Genetic Map of Rice

Directory of Open Access Journals (Sweden)

Ningfei Jiang

2017-07-01

Full Text Available Mapping major quantitative trait loci (QTL responsible for rice seed germinability under low temperature (GULT can provide valuable genetic source for improving cold tolerance in rice breeding. In this study, 124 rice backcross recombinant inbred lines (BRILs derived from a cross indica cv. Changhui 891 and japonica cv. 02428 were genotyped through re-sequencing technology. A bin map was generated which includes 3057 bins covering distance of 1266.5 cM with an average of 0.41 cM between markers. On the basis of newly constructed high-density genetic map, six QTL were detected ranging from 40 to 140 kb on Nipponbare genome. Among these, two QTL qCGR8 and qGRR11 alleles shared by 02428 could increase GULT and seed germination recovery rate after cold stress, respectively. However, qNGR1 and qNGR4 may be two major QTL affecting indica Changhui 891germination under normal condition. QTL qGRR1 and qGRR8 affected the seed germination recovery rate after cold stress and the alleles with increasing effects were shared by the Changhui 891 could improve seed germination rate after cold stress dramatically. These QTL could be a highly valuable genetic factors for cold tolerance improvement in rice lines. Moreover, the BRILs developed in this study will serve as an appropriate choice for mapping and studying genetic basis of rice complex traits.

Low temperature modification of gamma-irradiation effect on peas. II.Low temperature effect on the radio-sensitivity and the chlorophyll mutations

International Nuclear Information System (INIS)

Najdenova, N.; Vasileva, M.

1976-01-01

Dry pea seeds of cv.Ramonskii 77 with 11-12% moisture were γ-irradiated by 60 Co in doses 5, 15, 20 and 30 krad. Low temperature (-78 deg C) was effected in the form of dry ice for a 24 h period prior to, at the time of and post irradiation. As control were used: (a) dry non-irradiated seeds, stored at room temperature; (b) non-irradiated seeds subjected to low temperature (-78 deg C) for a 24 h period. and (c) seeds irradiated by the named doses, stored at room temperature until the time of irradiation. Treated and control seeds were sown in the field. Germination, survival rate and sterility were recorded in M 1 , while in M 2 chlorophyll mutations were scored. Results obtained showed that low temperature modification effect on the various irradiation doses depended on the time of its application; low temperature (-78 deg C) treatment prior to seed irradiation with doses 15, 20 and 30 krad increased germination percentage, plant survival and yield components in M 1 . The post-irradiation treatment did not have a significant effect on gamma-rays; highest protection effect was obtained in case seeds were irradiated at low temperature and then received supplementary treatment at high temperature. In this way the damaging effect of radiation was reduced to a maximum degree; low temperature treatment prior to irradiation with doses of 15 and 20 krad or at the time of irradiation with doses of 15, 20 and 30 krad resulted in a considerably wider chlorophyll mutation spectrum. (author)

Antagonistic effects of high and low temperature pretreatments on the germination and pregermination ethylene synthesis of lettuce seeds.

Science.gov (United States)

Burdett, A N

1972-08-01

Red light-induced germination of Grand Rapids lettuce seeds (Lactuca sativa L.) incubated at 20 C was inhibited if the seeds were first imbibed at 30 C for 36 hours. This effect was counteracted by exogenous ethylene and associated with a reduction in the rate at which the seeds produced ethylene throughout the pregermination period. A chilling treatment reversed the effect of a prior imbibition at 30 C on both germination and ethylene production. The possibility that the pretreatments influence germination through their effects on ethylene production is discussed.Other evidence presented indicates that the inability of seeds to germinate at supraoptimal temperature is not due either to a rapid loss of far red-absorbing phytochrome or to an inadequate capacity for ethylene synthesis. It was also shown that a chilling treatment potentiated germination at high temperature without affecting the ethylene synthetic capacity of the seeds.

BP-ANN for fitting the temperature-germination model and its application in predicting sowing time and region for Bermudagrass.

Directory of Open Access Journals (Sweden)

Erxu Pi

Full Text Available Temperature is one of the most significant environmental factors that affects germination of grass seeds. Reliable prediction of the optimal temperature for seed germination is crucial for determining the suitable regions and favorable sowing timing for turf grass cultivation. In this study, a back-propagation-artificial-neural-network-aided dual quintic equation (BP-ANN-QE model was developed to improve the prediction of the optimal temperature for seed germination. This BP-ANN-QE model was used to determine optimal sowing times and suitable regions for three Cynodon dactylon cultivars (C. dactylon, 'Savannah' and 'Princess VII'. Prediction of the optimal temperature for these seeds was based on comprehensive germination tests using 36 day/night (high/low temperature regimes (both ranging from 5/5 to 40/40°C with 5°C increments. Seed germination data from these temperature regimes were used to construct temperature-germination correlation models for estimating germination percentage with confidence intervals. Our tests revealed that the optimal high/low temperature regimes required for all the three bermudagrass cultivars are 30/5, 30/10, 35/5, 35/10, 35/15, 35/20, 40/15 and 40/20°C; constant temperatures ranging from 5 to 40°C inhibited the germination of all three cultivars. While comparing different simulating methods, including DQEM, Bisquare ANN-QE, and BP-ANN-QE in establishing temperature based germination percentage rules, we found that the R(2 values of germination prediction function could be significantly improved from about 0.6940-0.8177 (DQEM approach to 0.9439-0.9813 (BP-ANN-QE. These results indicated that our BP-ANN-QE model has better performance than the rests of the compared models. Furthermore, data of the national temperature grids generated from monthly-average temperature for 25 years were fit into these functions and we were able to map the germination percentage of these C. dactylon cultivars in the national scale

Impact of storage conditions on seed germination and seedling growth of wild oat (Avena fatua L. at different temperatures

Directory of Open Access Journals (Sweden)

Marija Sarić-Krsmanović

2015-12-01

Full Text Available The influence of seed storage conditions and different temperatures (5˚C, 10˚C, 15˚C, 20˚C, 25˚C, 30˚C and 26˚C/21˚C during germination and seedling development on seed germination, shoot length and germination rate of wild oat (Avena fatua L. was examined. Germinated seeds were counted daily over a period of ten days and shoot length was measured on the last day, while germination rates were calculated from those measurements. The results showed that seed storage under controlled conditions (T1: temperature 24±1°C, humidity 40-50%; T2: temperature 26±1°C, humidity 70-80% and T3: temperature 4˚C for periods of 3 (t1 and 12 (t2 months had a significant influence on germination of wild oat seeds. The percentage of germinated seeds under all examined temperatures was higher when they were stored for 12 months under controlled temperature and humidity. The results also showed that temperature had a significant effect on the percentage of germination and germination rate of A. fatua seeds. The highest total germination occurred at 15˚C temperature (T1: t1 - 41.25%, t2 - 44.37%; T2: t1 - 28.13%, t2 - 34.37%; T3: t1 - 10.63%, t2 - 12.50%. Germination percentage under an alternating day /night photoperiod at 26˚C/21˚C temperature was higher in all treatment variants (T1: t1 - 8.13%, t2 - 10.00%; T2: t1 - 11.87%, t2 - 13.13%; T3: t1 - 2.42%, t2 - 2.70% than germination in the dark at 25˚C, 30˚C and 5˚C.

Temperature and light intensity interaction on Cercospora coffeicola sporulation and conidia germination

Directory of Open Access Journals (Sweden)

Marília Goulart da Silva

2016-04-01

Full Text Available ABSTRACT Difficulty in obtaining abundant sporulation in culture of many species of Cercospora may be the limiting factor for studies of biology, systematics, and inoculation of the genus. Therefore, it is necessary to understand the nutritional and environmental requirements that influence mycelial growth, sporulation and germination. As it is difficult to obtain conidia of Cercospora coffeicola in vitro, different temperatures (17, 22, 27, and 32 °C and light intensities (80, 160, 240, and 320 μmol m-2 s-1 were evaluated to optimize pathogen sporulation and assess favorable conditions for spore germination, aiming for a strategy of disease control. The dark treatment (0 μmol m-2 s-1 was added for sporulation. A significant interaction was found between temperature and light intensity for both variables. The highest sporulation rate of C. coffeicola occurred at a light intensity of 240 μmol m-2 s-1 and air temperature of 22 °C, reaching 5.9x106 con mL-1. Germination was higher at temperature 17 °C and light intensity of 320 μmol m-2 s-1, reaching 52%. Interaction between light intensity and temperature proved to influence the processes of sporulation and germination of C. coffeicola.

The Effects of Light and Temperature on Germination of Stevia (Stevia rebaudiana BERT. Seeds

Directory of Open Access Journals (Sweden)

Esra UÇAR

2016-03-01

Full Text Available The Stevia rebaudiana (Bert. Bertoni is a perennial herbaceous plant and belongs to family of Asteraceae (Compositae. The contents of S. rebaudiana (Bert. Bertoni consist mainly non-caloric stevioside and rebaudioside A sweeteners. Low seed germination is an important problem in stevia cultivation. Therefore in this study, the effects of light and temperature on germination performance of stevia seeds were studied. Stevia rebaudiana seeds were treated with two lights (light/darkness and four different temperatures (15 ºC, 20 ºC, 25 ºC, 30 ºC. For each treatment, 50 seeds were counted and placed into petri dishes. Experiments were conducted as a randomized complete design method with three replicates. Germination was started within 6 to 10 days depending on the treatments. The highest seed germination rate (71% was observed in darkness/25 ºC temperature and followed by darkness/20 ºC (68% and light/25 ºC (67%. On the other hand, the lowest seed germination rate (31% was obtained from 15 ºC in both light and dark conditions and followed by darkness/30 ºC (43% and light/30 ºC (49%. The results showed that lower (15 ºC and higher (30 ºC temperatures significantly decreased the germination rates of stevia independently from the light treatments.

Substrates and temperatures in the germination of Eriotheca gracilipes seeds

Directory of Open Access Journals (Sweden)

Paulo Alexandre Fernandes Rodrigues de Melo

Full Text Available ABSTRACT The Eriotheca gracilipes (K. Schum. A. Robyns is a forest specie that belongs to the Bombacaceae family and is considered an endemic specie from the Brazilian savanna. The aim of this study was to evaluate the best substrate and temperature for the vigor and germination test of E. gracilipes seeds. The experiment was carried out in a randomized design with a 4 x 7 factorial, with 28 treatments with the combination of four temperatures (20; 25; 30 and 20-30 ºC and seven substrates (coarse vermiculite, medium vermiculite, sand, Basaplant®, paper towel, on and between filter papers, with 4 repetitions of 25 seeds each. It was assessed germination, first count of germination, and germination speed index. In conclusion, for germination and vigor tests of Eriotheca gracilipes seeds it is recommended the paper roll as substrate at temperatures of 20-30, 25 or 30 ºC, and the Basaplant® and paper roll at the temperature of 30 ºC, respectively.

A model for quantification of temperature profiles via germination times

DEFF Research Database (Denmark)

Pipper, Christian Bressen; Adolf, Verena Isabelle; Jacobsen, Sven-Erik

2013-01-01

Current methodology to quantify temperature characteristics in germination of seeds is predominantly based on analysis of the time to reach a given germination fraction, that is, the quantiles in the distribution of the germination time of a seed. In practice interpolation between observed...... time and a specific type of accelerated failure time models is provided. As a consequence the observed number of germinated seeds at given monitoring times may be analysed directly by a grouped time-to-event model from which characteristics of the temperature profile may be identified and estimated...... germination fractions at given monitoring times is used to obtain the time to reach a given germination fraction. As a consequence the obtained value will be highly dependent on the actual monitoring scheme used in the experiment. In this paper a link between currently used quantile models for the germination...

Germination response of Hylocereus setaceus (Salm-Dyck ex DC: ) Ralf Bauer (Cactaceae) seeds to temperature and reduced water potentials.

Science.gov (United States)

Simão, E; Takaki, M; Cardoso, V J M

2010-02-01

The germination response of Hylocereus setaceus seeds to isothermic incubation at different water potentials was analysed by using the thermal time and hydrotime models, aiming to describe some germination parameters of the population and to test the validity of the models to describe the response of the seeds to temperature and water potential. Hylocereus setaceus seeds germinated relatively well in a wide range of temperatures and the germination was rate limited from 11 to 20 degrees C interval and beyond 30 degrees C until 40 degrees C, in which the germination rate respectively shifts positively and negatively with temperature. The minimum or base temperature (T(b)) for the germination of H. setaceus was 7 degrees C, and the ceiling temperature varied nearly from 43.5 to 59 degrees C depending on the percent fraction, with median set on 49.8 degrees C. The number of degrees day necessary for 50% of the seeds to germinate in the infra-optimum temperature range was 39.3 degrees C day, whereas at the supra-optimum interval the value of theta = 77 was assumed to be constant throughout. Germination was sensitive to decreasing values of psi in the medium, and both the germinability and the germination rate shift negatively with the reduction of psi, but the rate of reduction changed with temperature. The values of base water potential (psi(b)) shift to zero with increasing temperatures and such variation reflects in the relatively greater effect of low psi on germination in supra optimum range of T. In general, the model described better the germination time courses at lower than at higher water potentials. The analysis also suggest that Tb may not be independent of psi and that psi(b(g)) may change as a function of temperature at the infra-otimum temperature range.

Constant and alternating temperature effects on germination and early growth of scorzonera

OpenAIRE

Dias, A.S.; Dias, L.S.; Pereira, I.P.

2013-01-01

Scorzonera is a threatened species in Portugal. Given the role of temperature in germination and seedling recruitment, the performance of total germination, lag of germination, duration of germination, shape of germination, root and hypocotyl length, and relative root growth of scorzonera was investigated under constant and alternating temperatures between 10 and 25ºC. Because of scorzonera’s rarity and threatened status, seeds of cultivated scorzonera were used, providing the framework for h...

The temperature effect of low-energy ion beam implantation on seed

International Nuclear Information System (INIS)

Chang Shenghe; Su Mingjie; Qin Guangyong; Wu Yuping; Zhao Haizhen

2005-01-01

The temperature effects of low-energy ion beam implantation on the seed germination were studied. Maize dry seeds were covered with copy paper, aluminum foil and without cover, respectively. Results showed that the germination rate of the seeds covered with paper which was the bad heat transmitter was the highest among three treatments, while that covered with aluminum foil which can transmit heat energy well was the least. The germination rate of the seeds covered with nothing was the second. Temperature affected seeds germination markedly. Generally the temperature of the target room inhibited the seeds' germination. After minus the effects of the temperature in the target room, the germination rates of the seeds were modified in this paper. The modified germination rate curve was also provided. (authors)

Determination of Germination Response to Temperature and Water Potential for a Wide Range of Cover Crop Species and Related Functional Groups.

Science.gov (United States)

Tribouillois, Hélène; Dürr, Carolyne; Demilly, Didier; Wagner, Marie-Hélène; Justes, Eric

2016-01-01

A wide range of species can be sown as cover crops during fallow periods to provide various ecosystem services. Plant establishment is a key stage, especially when sowing occurs in summer with high soil temperatures and low water availability. The aim of this study was to determine the response of germination to temperature and water potential for diverse cover crop species. Based on these characteristics, we developed contrasting functional groups that group species with the same germination ability, which may be useful to adapt species choice to climatic sowing conditions. Germination of 36 different species from six botanical families was measured in the laboratory at eight temperatures ranging from 4.5-43°C and at four water potentials. Final germination percentages, germination rate, cardinal temperatures, base temperature and base water potential were calculated for each species. Optimal temperatures varied from 21.3-37.2°C, maximum temperatures at which the species could germinate varied from 27.7-43.0°C and base water potentials varied from -0.1 to -2.6 MPa. Most cover crops were adapted to summer sowing with a relatively high mean optimal temperature for germination, but some Fabaceae species were more sensitive to high temperatures. Species mainly from Poaceae and Brassicaceae were the most resistant to water deficit and germinated under a low base water potential. Species were classified, independent of family, according to their ability to germinate under a range of temperatures and according to their base water potential in order to group species by functional germination groups. These groups may help in choosing the most adapted cover crop species to sow based on climatic conditions in order to favor plant establishment and the services provided by cover crops during fallow periods. Our data can also be useful as germination parameters in crop models to simulate the emergence of cover crops under different pedoclimatic conditions and crop

The impact of global warming on germination and seedling emergence in Alliaria petiolata, a woodland species with dormancy loss dependent on low temperature.

Science.gov (United States)

Footitt, S; Huang, Z; Ölcer-Footitt, H; Clay, H; Finch-Savage, W E

2018-03-23

The impact of global warming on seed dormancy loss and germination was investigated in Alliaria petiolata (garlic mustard), a common woodland/hedgerow plant in Eurasia, considered invasive in North America. Increased temperature may have serious implications, since seeds of this species germinate and emerge at low temperatures early in spring to establish and grow before canopy development of competing species. Dormancy was evaluated in seeds buried in field soils. Seedling emergence was also investigated in the field, and in a thermogradient tunnel under global warming scenarios representing predicted UK air temperatures through to 2080. Dormancy was simple, and its relief required the accumulation of low temperature chilling time. Under a global warming scenario, dormancy relief and seedling emergence declined and seed mortality increased as soil temperature increased along a thermal gradient. Seedling emergence advanced with soil temperature, peaking 8 days earlier under 2080 conditions. The results indicate that as mean temperature increases due to global warming, the chilling requirement for dormancy relief may not be fully satisfied, but seedling emergence will continue from low dormancy seeds in the population. Adaptation resulting from selection of this low dormancy proportion is likely to reduce the overall population chilling requirement. Seedling emergence is also likely to keep pace with the advancement of biological spring, enabling A. petiolata to maintain its strategy of establishment before the woodland canopy closes. However, this potential for adaptation may be countered by increased seed mortality in the seed bank as soils warm. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

The effect of cytokinins on flax seed germination at low temperature

Directory of Open Access Journals (Sweden)

Irena Niedźwiedź-Siegień

2011-01-01

Full Text Available Germination of flax seeds (Linum usitatissimum L., cv. Szafir at 5oC was enhanced by continuous white light, gibberellin A3 (GA3, kinetin and benzylaminopurine. GA3 and kinetin at physiological concentrations (10-8-10-6 M improved significantly germination in darkness. Stimulatory effect of benzylaminopurine was visible only in the light. Almost no effect of zeatin and isopentenyladenine (2iP on germination was observed. Possible causes of this differences were suggested.

Seed germination behavior of swallow wort

Directory of Open Access Journals (Sweden)

amir hosein pahlavani

2009-06-01

Full Text Available The exotic plant, Swallow- wort, a twining perennial of the Milkweed family, has become increasingly invasive in some place of Iran, especially orchards. Increased knowledge of wort germination biology would facilitate development of an optimum control program. Germination of Swallow wort seeds as affected by environmental factors was studied under controlled-environment growth chamber conditions. The following studies were conducted in plant Pests & Diseases Research Institute during the years 2003-4: 1- Effect of constant temperature on germination that including 10, 15, 18, 20, 25, 30, 35 and 40˚C; 2- Effect of light on constant germination; 3- Effect of temperature fluctuations on seed germination: 15/7, 20/12, 25/17 and 30/22˚C. All experiments were conducted with 8 replications. Swallow wort seeds showed no dormancy when detachment from mother plant. Seed germination was strongly influenced by temperature. Light did not play a crucial role on seed germination of this weed. Therefore Swallow wort seeds were not photoblastic and temperature fluctuations did not increase seed germination of Swallow wort. The above characteristics are very important in making swallowwort an invasive weed. Having precise information of these traits enables us to a better management and control of this troublesome weed.

Temperature requirements for seed germination of Pereskia aculeata and Pereskia grandifolia.

Science.gov (United States)

Souza, Lucéia F; Gasparetto, Bruno F; Lopes, Rodrigo R; Barros, Ingrid B I

2016-04-01

Pereskia aculeata and Pereskia grandifolia have been studied widely due to their high nutritional and therapeutic values. However, little is known about the biological requirements of their seeds for the various germination factors. Thus, this experiment aimed to evaluate the thermal effects on the germination of these species at the temperatures of 24°C, 27°C, 30°C, 33°C and 36°C. After verification of the existence of differences in the performance of germination, a non-linear regression was carried out, relating the germination to temperature and identifying its point of maximum efficiency. We found that the lowest synchronization indexes of germination were observed close to 30°C. The best germination response of the P. aculeata and P. grandifolia was observed at 30°C and 33°C, respectively, with greater germination strength and fewer days to attain 63.21% of germinations. The results obtained from the germination of P. aculeata and P. grandifolia can be described by the Weindull distribution model with three parameters, as proposed by Carneiro and Guedes (1992). Copyright © 2016 Elsevier Ltd. All rights reserved.

Abscisic acid regulates seed germination of Vellozia species in response to temperature.

Science.gov (United States)

Vieira, B C; Bicalho, E M; Munné-Bosch, S; Garcia, Q S

2017-03-01

The relationship between the phytohormones, gibberellin (GA) and abscisic acid (ABA) and light and temperature on seed germination is still not well understood. We aimed to investigate the role of the ABA and GA on seed germination of Vellozia caruncularis, V. intermedia and V. alutacea in response to light/dark conditions on different temperature. Seeds were incubated in GA (GA 3 or GA 4 ) or ABA and their respective biosynthesis inhibitors (paclobutrazol - PAC, and fluridone - FLU) solutions at two contrasting temperatures (25 and 40 °C). Furthermore, endogenous concentrations of active GAs and those of ABA were measured in seeds of V. intermedia and V. alutacea during imbibition/germination. Exogenous ABA inhibited the germination of Vellozia species under all conditions tested. GA, FLU and FLU + GA 3 stimulated germination in the dark at 25 °C (GA 4 being more effective than GA 3 ). PAC reduced seed germination in V. caruncularis and V. alutacea, but did not affect germination of V. intermedia at 40 °C either under light or dark conditions. During imbibition in the dark, levels of active GAs decreased in the seeds of V. intermedia, but were not altered in those of V. alutacea. Incubation at 40 °C decreased ABA levels during imbibition in both V. caruncularis and V. alutacea. We conclude that the seeds of Vellozia species studied here require light or high temperature to germinate and ABA has a major role in the regulation of Vellozia seed germination in response to light and temperature. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Responses of quinoa (Chenopodium quinoa Willd. seeds stored under different germination temperatures

Directory of Open Access Journals (Sweden)

Andressa Strenske

2017-01-01

Full Text Available In this experiment, we assessed the germination and vigor of quinoa seeds packed in paper bags and stored at room temperature for 36, 85, 119, 146, 177 and 270 days. The seeds were harvested under experimental conditions in Marechal Candido Rondon, Paraná, during the 2012/13 growing seasons. Four replicates of 100 seeds each were established for each storage time, and the seeds were evaluated, on paper, based on the BOD under the following experimental temperature conditions: alternating temperatures of 20 and 30°C and a constant temperature of 25°C. The seeds from both treatments were subject to seven-hour photoperiods and 25°C under continuous darkness. The germinated seeds were counted daily for eight days after sowing, and we evaluated the percentages of normal and abnormal seedlings and the germination index. The experimental design was completely randomized using a split-plot design. Increasing the storage time decreased the percentage of germinated seeds and seed vigor due to the increased number of abnormal seedlings. Over the 430-day study period, quinoa seed germination completely declined under the experimental conditions. The final number of germinating seeds should be evaluated 7 days after the beginning of the germination test.

Physical characterization of Rhipsalis (Cactaceae fruits and seeds germination in different temperatures and light regimes

Directory of Open Access Journals (Sweden)

A. B. Lone

Full Text Available Abstract The germination characteristics of the native cactus species are poorly known, being the temperature and the light the factors that the most interferes in that process. Thus, the objective of the present work was to characterize the fruits and evaluate the influence of the temperature and the light in the seed germination of Rhipsalis floccosa, Rhipsalis pilocarpa and Rhipsalis teres. The tested constant temperatures were 15, 20, 25, 30 and 35 °C and the alternate of 20-30 °C and 25-35 °C in a photoperiod of 10 hours, and with determination of the most appropriate temperature, the germination was tested in light absence. The germination percentage, the index of germination speed and medium time of germination were evaluated. For R. floccosa, the highest germination percentage was at 20 °C. For R. pilocarpa and R. teres, the highest germination percentages occurred in 15 °C and 20 °C. There was correlation to germination percentage between the three species, indicating that they had similar germination behavior. Total absence of germination was verified for the three species in condition of light absence. In conclusion, the temperature of 20 °C is the most suitable for the seed germination of R. floccosa. For the species R. pilocarpa and R. teres, the temperatures of 15 and 20 °C are the most suitable.

Physical characterization of Rhipsalis (Cactaceae) fruits and seeds germination in different temperatures and light regimes.

Science.gov (United States)

Lone, A B; Colombo, R C; Andrade, B L G; Takahashi, L S A; Faria, R T

2016-06-01

The germination characteristics of the native cactus species are poorly known, being the temperature and the light the factors that the most interferes in that process. Thus, the objective of the present work was to characterize the fruits and evaluate the influence of the temperature and the light in the seed germination of Rhipsalis floccosa, Rhipsalis pilocarpa and Rhipsalis teres. The tested constant temperatures were 15, 20, 25, 30 and 35 °C and the alternate of 20-30 °C and 25-35 °C in a photoperiod of 10 hours, and with determination of the most appropriate temperature, the germination was tested in light absence. The germination percentage, the index of germination speed and medium time of germination were evaluated. For R. floccosa, the highest germination percentage was at 20 °C. For R. pilocarpa and R. teres, the highest germination percentages occurred in 15 °C and 20 °C. There was correlation to germination percentage between the three species, indicating that they had similar germination behavior. Total absence of germination was verified for the three species in condition of light absence. In conclusion, the temperature of 20 °C is the most suitable for the seed germination of R. floccosa. For the species R. pilocarpa and R. teres, the temperatures of 15 and 20 °C are the most suitable.

Lab and Field Warming Similarly Advance Germination Date and Limit Germination Rate for High and Low Elevation Provenances of Two Widespread Subalpine Conifers

Directory of Open Access Journals (Sweden)

Lara M. Kueppers

2017-11-01

Full Text Available Accurately predicting upslope shifts in subalpine tree ranges with warming requires understanding how future forest populations will be affected by climate change, as these are the seed sources for new tree line and alpine populations. Early life history stages are particularly sensitive to climate and are also influenced by genetic variation among populations. We tested the climate sensitivity of germination and initial development for two widely distributed subalpine conifers, using controlled-environment growth chambers with one temperature regime from subalpine forest in the Colorado Rocky Mountains and one 5 °C warmer, and two soil moisture levels. We tracked germination rate and timing, rate of seedling development, and seedling morphology for two seed provenances separated by ~300 m elevation. Warming advanced germination timing and initial seedling development by a total of ~2 weeks, advances comparable to mean differences between provenances. Advances were similar for both provenances and species; however, warming reduced the overall germination rate, as did low soil moisture, only for Picea engelmannii. A three-year field warming and watering experiment planted with the same species and provenances yielded responses qualitatively consistent with the lab trials. Together these experiments indicate that in a warmer, drier climate, P. engelmannii germination, and thus regeneration, could decline, which could lead to declining subalpine forest populations, while Pinus flexilis forest populations could remain robust as a seed source for upslope range shifts.

Seed dormancy and germination of Halophila ovalis mediated by simulated seasonal temperature changes

Science.gov (United States)

Statton, John; Sellers, Robert; Dixon, Kingsley W.; Kilminster, Kieryn; Merritt, David J.; Kendrick, Gary A.

2017-11-01

The seagrass, Halophila ovalis plays an important ecological and sediment stability role in estuarine systems in Australia with the species in decline in many sites. Halophila ovalis is a facultative annual, relying mainly on recruitment from the sediment seed bank for the annual regeneration of meadows. Despite this, there is little understanding of seed dormancy releasing mechanisms and germination cues. Using H. ovalis seed from the warm temperate Swan River Estuary in Western Australia, the germination ecology of H. ovalis was investigated by simulating the natural seasonal variation in water temperatures. The proportion of germinating seeds was found to be significantly different among temperature treatments (p < 0.001). The treatment with the longest period of cold exposure at 15 °C followed by an increase in temperature to 20-25 °C (i.e. cold stratification) had the highest final mean germination of 32% and the fastest germination rate. Seeds exposed to constant mean winter temperatures of 15 °C had the slowest germination rate with less than two seeds germinating over 118 days. Thus temperature is a key germination cue for H. ovalis seeds and these data infer that cold stratification is an important dormancy releasing mechanism. This finding has implications for recruitment in facultative annual species like H. ovalis under global warming since the trend for increasing water temperatures in the region may limit seed-based recruitment in the future.

Multiple paths to similar germination behavior in Arabidopsis thaliana.

Science.gov (United States)

Burghardt, Liana T; Edwards, Brianne R; Donohue, Kathleen

2016-02-01

Germination timing influences plant fitness, and its sensitivity to temperature may cause it to change as climate shifts. These changes are likely to be complex because temperatures that occur during seed maturation and temperatures that occur post-dispersal interact to define germination timing. We used the model organism Arabidopsis thaliana to determine how flowering time (which defines seed-maturation temperature) and post-dispersal temperature influence germination and the expression of genetic variation for germination. Germination responses to temperature (germination envelopes) changed as seeds aged, or after-ripened, and these germination trajectories depended on seed-maturation temperature and genotype. Different combinations of genotype, seed-maturation temperature, and after-ripening produced similar germination envelopes. Likewise, different genotypes and seed-maturation temperatures combined to produce similar germination trajectories. Differences between genotypes were most likely to be observed at high and low germination temperatures. The germination behavior of some genotypes responds weakly to maternal temperature but others are highly plastic. We hypothesize that weak dormancy induction could synchronize germination of seeds dispersed at different times. By contrast, we hypothesize that strongly responsive genotypes may spread offspring germination over several possible germination windows. Considering germination responses to temperature is important for predicting phenology expression and evolution in future climates. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Constant temperatures and the rate of seed germination in maize ...

African Journals Online (AJOL)

The rate of germination of the NEM cultivar was faster than that of the QPM cultivar at all temperatures. The thermal times for median germination were 46 for QPM and 40.7 oCd for the NEM cultivar. The cardinal temperatures (base, Tb, optimum, To and ceiling, Tc) for the NEM cultivar were Tb: 7, To: 30 and Tc: 48.2 oC.

The role of the Arabidopsis FUSCA3 transcription factor during inhibition of seed germination at high temperature.

Science.gov (United States)

Chiu, Rex S; Nahal, Hardeep; Provart, Nicholas J; Gazzarrini, Sonia

2012-01-27

Imbibed seeds integrate environmental and endogenous signals to break dormancy and initiate growth under optimal conditions. Seed maturation plays an important role in determining the survival of germinating seeds, for example one of the roles of dormancy is to stagger germination to prevent mass growth under suboptimal conditions. The B3-domain transcription factor FUSCA3 (FUS3) is a master regulator of seed development and an important node in hormonal interaction networks in Arabidopsis thaliana. Its function has been mainly characterized during embryonic development, where FUS3 is highly expressed to promote seed maturation and dormancy by regulating ABA/GA levels. In this study, we present evidence for a role of FUS3 in delaying seed germination at supraoptimal temperatures that would be lethal for the developing seedlings. During seed imbibition at supraoptimal temperature, the FUS3 promoter is reactivated and induces de novo synthesis of FUS3 mRNA, followed by FUS3 protein accumulation. Genetic analysis shows that FUS3 contributes to the delay of seed germination at high temperature. Unlike WT, seeds overexpressing FUS3 (ML1:FUS3-GFP) during imbibition are hypersensitive to high temperature and do not germinate, however, they can fully germinate after recovery at control temperature reaching 90% seedling survival. ML1:FUS3-GFP hypersensitivity to high temperature can be partly recovered in the presence of fluridone, an inhibitor of ABA biosynthesis, suggesting this hypersensitivity is due in part to higher ABA level in this mutant. Transcriptomic analysis shows that WT seeds imbibed at supraoptimal temperature activate seed-specific genes and ABA biosynthetic and signaling genes, while inhibiting genes that promote germination and growth, such as GA biosynthetic and signaling genes. In this study, we have uncovered a novel function for the master regulator of seed maturation, FUS3, in delaying germination at supraoptimal temperature. Physiologically, this is

The role of the Arabidopsis FUSCA3 transcription factor during inhibition of seed germination at high temperature

Directory of Open Access Journals (Sweden)

Chiu Rex S

2012-01-01

Full Text Available Abstract Background Imbibed seeds integrate environmental and endogenous signals to break dormancy and initiate growth under optimal conditions. Seed maturation plays an important role in determining the survival of germinating seeds, for example one of the roles of dormancy is to stagger germination to prevent mass growth under suboptimal conditions. The B3-domain transcription factor FUSCA3 (FUS3 is a master regulator of seed development and an important node in hormonal interaction networks in Arabidopsis thaliana. Its function has been mainly characterized during embryonic development, where FUS3 is highly expressed to promote seed maturation and dormancy by regulating ABA/GA levels. Results In this study, we present evidence for a role of FUS3 in delaying seed germination at supraoptimal temperatures that would be lethal for the developing seedlings. During seed imbibition at supraoptimal temperature, the FUS3 promoter is reactivated and induces de novo synthesis of FUS3 mRNA, followed by FUS3 protein accumulation. Genetic analysis shows that FUS3 contributes to the delay of seed germination at high temperature. Unlike WT, seeds overexpressing FUS3 (ML1:FUS3-GFP during imbibition are hypersensitive to high temperature and do not germinate, however, they can fully germinate after recovery at control temperature reaching 90% seedling survival. ML1:FUS3-GFP hypersensitivity to high temperature can be partly recovered in the presence of fluridone, an inhibitor of ABA biosynthesis, suggesting this hypersensitivity is due in part to higher ABA level in this mutant. Transcriptomic analysis shows that WT seeds imbibed at supraoptimal temperature activate seed-specific genes and ABA biosynthetic and signaling genes, while inhibiting genes that promote germination and growth, such as GA biosynthetic and signaling genes. Conclusion In this study, we have uncovered a novel function for the master regulator of seed maturation, FUS3, in delaying

Effect of Temperature Regimes on Seed Germination Asafoetida (Ferula Assafoetida L.

Directory of Open Access Journals (Sweden)

Zangoie M.

2014-12-01

Full Text Available Asafoetida is a medicinal plant belonging to the Apiaceae family. Gum obtained from the lower part of the stem and roots of this plant has many industrial and pharmaceutical applications. This plant is subject to extinction in its natural habitats due to over-utilization. Understanding the biology of seed germination can help to restore such degradation by implementing agricultural development programs. The present study is an attempt to determine the germination responses to two temperature regimes (constant and fluctuating during the course of the study. The experiment was planned based on a factorial-completely randomized design with two factors (constant and fluctuating temperature regimes at 3 levels each (15, 20 and 25°C with 4 replications. The results showed that the characteristics of germination in asafoetida were significantly improved under the fluctuating temperature as compared with the constant regime. It showed a mean germination time of 1.88 days for the fluctuating regime, while it was 4.88 days for the constant regime. The same results were found on germination rates in favor of fluctuating (0.62 per day in comparison with constant regime (0.33 per day. Under the fluctuating regime, the lowest level of imposed temperature (daily application of 10 and 20 degree during the first and the second 12 hours, respectively was the best for seed germination in this experiment.

[Effects of fluridone, gibberellin acid and germination temperature on dormancy-breaking for Epimedium wushanense].

Science.gov (United States)

Su, He; Wang, Yue; Yang, Yang; Dong, Xue-Hui

2016-07-01

We introduced Epimedium wushanense seed which has been stratified for 90 days at 10/20 ℃ as experimental materials, with which we studied the effects of fluridone, gibberellin acid and temperature on E. wushanense germination. The results were suggested as shown below. ①Temperature, fluridone and gibberellin acid can both solely or jointly affect germination energy, germination rate significantly. Among those factors, fluridone affect germination rate and germination energy the most, followed by gibberellin acid and temperature. The highest germination rate under 4 ℃ and 10/20 ℃ stratification are 79.3%, 72.0% respectively, which resulted from treatment of F10GA300 and F20GA200 respectively. The highest germination energy under 4 ℃ and 10/20 ℃ stratification are 52.7%, 52.0%, respectively, which both resulted from F20GA200. ②Compared with 4 ℃ germination, seed could not germinate at 10/20 ℃ germination. Nontheless, application of fluridone can lead E. wushanense seeds to germinating.③The effects of gibberellin acid and interaction between gibberellin acid and fluridone significantly affect seed rotten rate during germination. In addition, soaking is another remarkable factor which increased seed rotten rate. As a result, it is feasible to promote E. wushanense dormancy releasing with gibberellin acid and fluridone associating with a proper germination temperature. Further, it is necessary taking actions to avoid seed rotten rate for saving E. wushanense nurseries'cost. Copyright© by the Chinese Pharmaceutical Association.

Temperature regulates positively photoblastic seed germination in four ficus (moraceae) tree species from contrasting habitats in a seasonal tropical rainforest.

Science.gov (United States)

Chen, Hui; Cao, Min; Baskin, Jerry M; Baskin, Carol C

2013-08-01

Differences in seed germination responses of trees in tropical forests to temperature and light quality may contribute to their coexistence. We investigated the effects of temperature and red:far-red light (R:FR ratio) on seed germination of two gap-demanding species (Ficus hispida and F. racemosa) and two shade-tolerant species (F. altissima and F. auriculata) in a tropical seasonal rainforest in southwest China. A R:FR ratio gradient was created by filtering fluorescent light through polyester filters. Four temperature treatments were used to test the effect of temperature on seed germination of the four Ficus tree species across the R:FR gradient. Seeds of the four Ficus species were positively photoblastic. Seed germination of F. hispida and F. racemosa was not affected across the R:FR ratio gradient (0.25-1.19) at 25/35°C, but it was inhibited under low R:FR at 22/23°C. By contrast, germination percentages of F. altissima and F. auriculata were not inhibited along the entire light gradient in all temperature treatments. Differences in germination responses of Ficus species might contribute to differences in their habitat preferences. The inhibitory effect of understory temperatures in the forest might be a new mechanism that prevents positively photoblastic seeds of the gap-demanding species such as F. hispida and F. racemosa from germinating in the understory and in small canopy gaps.

Can heavy metal pollution defend seed germination against heat stress? Effect of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination under high temperature.

Science.gov (United States)

Deng, Benliang; Yang, Kejun; Zhang, Yifei; Li, Zuotong

2016-09-01

Heavy metal pollution, as well as greenhouse effect, has become a serious threat today. Both heavy metal and heat stresses can arrest seed germination. What response can be expected for seed germination under both stress conditions? Here, the effects of heavy metals (Cu(2+), Cd(2+) and Hg(2+)) on maize seed germination were investigated at 20 °C and 40 °C. Compared with 20 °C, heat stress induced thermodormancy. However, this thermodormancy could be significantly alleviated by the addition of a low concentration of heavy metals. Heavy metals, as well as heat stress induced H2O2 accumulation in germinating seeds. Interestingly, this low concentration of heavy metal that promoted seed germination could be partly blocked by DMTU (a specific ROS scavenger), irrespective of temperature. Accordingly, H2O2 addition reinforced this promoting effect on seed germination, which was induced by a low concentration of heavy metal. Furthermore, we found that the NADPH oxidase derived ROS was required for seed germination promoted by the heavy metals. Subsequently, treatment of seeds with fluridone (a specific inhibitor of ABA) or ABA significantly alleviated or aggravated thermodormancy, respectively. However, this alleviation or aggravation could be partly attenuated by a low concentration of heavy metals. In addition, germination that was inhibited by high concentrations of heavy metals was also partly reversed by fluridone. The obtained results support the idea that heavy metal-mediated ROS and hormone interaction can finally affect the thermodormancy release or not. Copyright © 2016 Elsevier Ltd. All rights reserved.

Seed Germination and Early Growth Responses of Hyssop, Sweet Basil and Oregano to Temperature Levels

Directory of Open Access Journals (Sweden)

Sajad MIJANI

2013-12-01

Full Text Available The objectives of this survey were to determine the effect of temperature on germination and seedling growth of Hyssop (Hyssopus officinalis L., Sweet basil (Ocimum basilicum L. and Oregano (Origanum vulgare L. (Lamiaceae family as well as comparing species regarding germination behavior and growth characteristics. Seeds were germinated on a temperature-gradient bar varying between 5 and 40 °C (with 5 °C intervals. Results indicated that the highest germination percentage of hyssop (92-98%, sweet basil (86-90% and oregano (74-77% occurred at 20-30 °C, 25-30 °C and 20-30 °C, respectively; therefore, moderate and warm temperatures are proper for germination of all species. In all species the maximum germination rate obtained at 30 °C. Among all species, Day 10 % of Sweet basil Germination had the lowest value, which indicates faster germination. The cardinal temperatures (base, optimum and ceiling or maximum were estimated by the segmented model. Base temperature (Tb was calculated for hyssop, sweet basil and oregano as 3.42, 5.70 and 5.46 °C, respectively. Optimal temperature (To calculated for all species was approximately 30°C, So warmer temperatures are much more proper for them. The species showed different maximum temperatures (Tm from 42.91 (Oregano to 48.05 °C (Hyssop. In Hyssop and Sweet basil optimum growth of seedlings were observed at 30°C while Oregano reached its best growth at 25°C. The difference between maximum and minimum temperatures of germination knowing as temperature range (TR index could show adaptation capability to broad sites for planting and domestication. Regarding this index Hyssop stood in the first place.

Quantifying cardinal temperatures and thermal time required for germination of Silybum marianum seed

Directory of Open Access Journals (Sweden)

Ghasem Parmoon

2015-04-01

Full Text Available The response of seed germination to environmental factors can be estimated by nonlinear regression. The present study was performed to compare four nonlinear regression models (segmented, beta, beta modified, and dent-like to describe the germination rate–temperature relationships of milk thistle (Silybum marianum L. at six constant temperatures, with the aim of identifying the cardinal temperatures and thermal times required to reach different germination percentiles. Models and statistical indices were calibrated using an iterative optimization method and their performance was compared by root mean square error (RMSE, coefficient of determination (R2 and Akaike information criterion correction (AICc. The beta model was found to be the best model for predicting the required time to reach 50% germination (D50, (R2 = 0.99; RMSE = 0.004; AICc = − 276.97. Based on the model outputs, the base, optimum, and maximum temperatures of seed germination were 5.19 ± 0.79, 24.01 ± 0.11, and 34.32 ± 0.36 °C, respectively. The thermal times required for 50% and 90% germination were 4.99 and 7.38 degree-days, respectively.

Substrates and temperatures for the germination test of Chorisia glaziovii (O. Kuntze seeds

Directory of Open Access Journals (Sweden)

Roberta Sales Guedes

2011-12-01

Full Text Available The species Chorisia glaziovii O. Kuntze is native to the northeast of Brazil, belongs to Bombacaceae family and has diversified uses in folk medicine, recovery of degraded areas and upholstery industry. The present work was realizated with the objective to determine the substrate type and temperature for conduction of germination tests with C. glaziovii seeds. The experiment was carried out in the Laboratory of Analysis of Seeds (CCA - UFPB, Areia City, Northeast of Brazil, in design completely randomized with the treatments distributed in outline factorial 4 x 4 (temperatures of 25, 30, 35 and 20-30°C and substrate towel paper, among blotting paper, between sand and between vermiculite. The following parameters were analyzed: germination percentage, first count germination, germination speed index, and length of seedlings. The temperature of 35°C was shown inadequate for conduction of germination and vigor tests of seeds of C. glaziovii, independently of the used substrates. It is recommended for conduction of the germination and vigor tests of the seeds of C. glaziovii the substrate between sand or towel paper, in the temperatures of 25 and 20-30°C.

Condicionamento osmótico de sementes de hortaliças visando a germinação em condições de temperaturas baixas Vegetable seed priming to improve germination at low temperature

Directory of Open Access Journals (Sweden)

Warley Marcos Nascimento

2005-06-01

Full Text Available Baixas temperaturas por ocasião do plantio podem atrasar ou inibir a germinação das sementes de várias espécies de hortaliças, incluindo berinjela, melancia, melão e tomate. O condicionamento osmótico de sementes tem sido utilizado com o objetivo de acelerar a germinação e uniformizar a emergência das plântulas em campo, especialmente em condições adversas. Sementes de berinjela 'Ciça', melancia 'Crimson Sweet', melão 'Top Net SR' e tomate 'Heinz 9425' foram osmoticamente condicionadas. A metodologia utilizada no condicionamento osmótico foi dependente da espécie, isto é, a solução osmótica, a temperatura bem como o período de condicionamento variou entre as diferentes espécies estudadas. Após o condicionamento osmótico, as sementes foram lavadas e secas. As sementes foram colocadas para germinar em condições de baixas temperaturas (10; 15; 15 e 17ºC para tomate, berinjela, melancia e melão, respectivamente e em temperaturas normais (20 e 30ºC para tomate e 25ºC para as demais espécies. Baixas temperaturas diminuíram a velocidade e a percentagem de germinação das sementes das quatro espécies. Sementes osmoticamente condicionadas de todas as espécies testadas apresentaram maior germinação do que aquelas não condicionadas, principalmente em condições de baixas temperaturas. O condicionamento osmótico pode ser utilizado para melhorar a germinação de sementes de cucurbitaceas (melão e melancia e solanaceas (berinjela e tomate, principalmente nestas condições adversas de baixas temperaturas.Under low temperatures, seed germination of several species, including eggplant, watermelon, melon and tomato can be erratic or completely inhibited. Seed priming has been used to increase germination rate and seedling uniformity, mainly under unfavorable environmental conditions. Seeds of eggplant, cv. 'Ciça', watermelon 'Crimson Sweet', melon 'Top Net SR' and tomato 'Heinz 9425' were osmoconditioned. The

Germination responses to current and future temperatures of four seeder shrubs across a latitudinal gradient in western Iberia.

Science.gov (United States)

Chamorro, Daniel; Luna, Belén; Moreno, José M

2017-01-01

Species differ in their temperature germination niche. Populations of a species may similarly differ across the distribution range of the species. Anticipating the impacts of climate variability and change requires understanding the differential sensitivity to germination temperature among and within species. Here we studied the germination responses of four hard-seeded Cistaceae seeders to a range of current and future temperatures. Seeds were collected at sites across the Iberian Peninsula and exposed or not exposed to a heat shock to break dormancy, then set to germinate under four temperature regimes. Temperatures were varied daily and seasonally, simulating the temperature range across the gradient, plus an increased temperature simulating future climate. Time to germination onset and cumulative germination at the end of each season were analyzed for the effects of temperature treatments, seasons, and local climate (temperature of the germination period, T gp ) at each site. T gp was a significant covariate of germination in all species but Cistus populifolius. Temperature treatments significantly affected Cistus ladanifer, C. salviifolius, and Halimium ocymoides. Germination occurred in simulated autumn conditions, with little germination occurring at later seasons, except in unheated seeds of H. ocymoides. Exposure to a heat shock changed the sensitivity to temperature treatments and the relationships with T gp . Germination responses to temperature differ not only among species but also within species across their latitudinal range. The responses were idiosyncratic and related to the local climate of the population. This germination variability complicates generalizing the impacts of climate variability and climate change. © 2017 Botanical Society of America.

valuation of Germination Characteristics for Hedysarum Criniferum Boiss in Alternative Temperature and Drought Stress Conditions

Directory of Open Access Journals (Sweden)

A. Shahbazi

2016-05-01

24-26 °C day-night and four drought levels (0, -2, -4, and -6 bar with three replications. According to the results, different levels of drought stress and alternative temperature had significant effects on germination percentage and germination speed of the species seeds (α=5%. The study showed that increasing temperature and drought levels leads to reducing the germination percentage and germination speed of the species. Higher germination percentage of H. criniferum seeds in different drought levels compared to alternative temperature levels of 24-26 °C indicated that this species is more sensitive to higher temperature than high levels of drought condition. Therefore, it could partly be concluded that the H. criniferum is a relatively drought resistance species.

Modelling the effect of temperature on seed germination in some ...

African Journals Online (AJOL)

The prediction of germination percentage (GP) and germination speed (GS) of the seeds for some cucurbits (watermelon, melon, cucumber, summer squash, pumpkin and winter squash) was investigated by mathematical model based on temperature. The model, D = [a - (b x T) + (c x T2)] of Uzun et al. (2001), was adapted ...

Effects of low dose gamma-ray radiation on the seed germination and physiological activity of vegetable crops

Energy Technology Data Exchange (ETDEWEB)

Kim, J. S.; Baek, M. H.; Lee, Y. G. [KAERI, Taejon (Korea, Republic of); Jung, K. H. [Kyunghee Univ., Yongin (Korea, Republic of)

2000-10-01

To determine the effect of low dose gamma-ray radiation on the germination rate and physiology of germinative seeds of Chinese cabbage(Brassica campestris L. cv. Hanyoreum) and radish(Raphanus sativus L. cv. Chungsukoungzoung). The germination rate of irradiation group was higher than that of the control. Especially it was highest at the early stage of induction. The germination rate of Chinese cabbage increased at 4 Gy-, 10 Gy- and 50 Gy irradiation group and that of radish increased at 2 Gy-, 6 Gy- and 10 Gy irradiation group. The seedling height of Chinese cabbage and radish increased positively in low dose irradiation group. The seedling height of Chinese cabbage was noticeably higher at 4 Gy and 10 Gy irradiation group and that of radish at 6 Gy irradiation group. The protein contents of seeds irradiated with low dose gamma-ray radiation was increased compared to that of the control especially at the early stage of induction. The enzyme activity of seeds irradiated with low dose of gamma-ray radiation was increased at 4 Gy and 10 Gy irradiation group. These results suggest that the germination and physiological activity of old seeds could be stimulated promisingly by the low dose gamma-ray radiation.

Inhibition of barley grain germination by light

NARCIS (Netherlands)

Roth-Bejerano, N.; Meulen, R.M. van der; Wang, M.

1996-01-01

Intact grains of barley (Hordeum distichum cv. Triumph) germinated rapidly in the dark or when exposed to brief daily light breaks in the temperature range 15-25°C, although germination proceeded less rapidly at low temperatures. Prolonged illumination (16 h/day) or continuous light inhibited

Effect of Low Dose gamma-ray Irradiation on the Germination and Growth in Red Pepper (Capcicum annuum L.)

International Nuclear Information System (INIS)

Lee Eun-Kyung; Kim Jae-Sung

1998-01-01

This study was conducted to determine the effect of low dose gamma-ray irradiation in red pepper. The germination percentage, plant, the number of flower, chlorophyll contents, leaf length and width were observed from plants grown with red pepper seeds irradiated with various low dose of gamma-ray. The germination percentage of irradiation group treatmented gamma-ray was much higher than that of the control. Specially the germination percentage after sowing red pepper seeds on paper towel was higher than 1,000 and 2,000 rad irradiation group. The height of plants grown with red pepper seeds irradiated with gamma-ray was increased in 100, 200 and 400 rad irradiation group compared to that of the control. The height of plant from 2,400 rad irradiation group, however, was shorter than that of the control. Nutrient contents of leaves of plants grown with red pepper seeds irradiated with various dose of gamma-ray were significantly increased in 800 and 1,200 rad irradiation group. Electric conductivity (EC) of the water used for seed germination was lower irradiation group than control group. Therefore, there was the possibility to increase the germination and plant growth with gamma-ray of adequate low dose

Preventing thermoinhibition in a thermosensitive lettuce genotype by seed imbibition at low temperature

Directory of Open Access Journals (Sweden)

Nascimento Warley Marcos

2003-01-01

Full Text Available Lettuce (Lactuca sativa L. seed germination is strongly temperature dependent and under high temperatures, germination of most of genotypes can be erratic or completely inhibited. Lettuce seeds of 'Dark Green Boston' (DGB were incubated at temperatures ranging from 15degrees to 35degreesC at light and dark conditions. Other seeds were imbibed in dark at 20degrees; 25degrees; 30degrees; and 35degreesC for 8 and 16 hours and then transferred to 20 or 35degreesC, in dark. Seeds were also incubated at constant temperature of 20degrees and 35 degreesC, in the dark, as control. In another treatment, seeds were primed for 3 days at 15degreesC with constant light. DGB lettuce seeds required light to germinate adequately at temperatures above 25degreesC. Seeds incubated at 20degreesC had 97% germination, whereas seeds incubated at 35degreesC did not germinate. Seeds imbibed at 20degreesC for 8 and 16 hours had germination. At 35degreesC, seeds imbibed initially at 20degreesC for 8 and 16 hours, had 89 and 97% germination, respectively. Seeds imbibed at 25degreesC for 16 hours, germinated satisfactory at 35degreesC. High temperatures of imbibition led to no germination. Primed and non-primed seeds had 100% germination at 20degreesC. Primed seeds had 100% germination at 35degreesC, whereas non-primed seeds germinate only 4%. The first hours of imbibition are very critical for lettuce seed germination at high temperatures.

DELAY OF GERMINATION 1 mediates a conserved coat-dormancy mechanism for the temperature- and gibberellin-dependent control of seed germination

Czech Academy of Sciences Publication Activity Database

Graeber, K.; Linkies, A.; Steinbrecher, T.; Tarkowská, Danuše; Turečková, Veronika; Ignatz, M.; Voegele, A.; Urbanová, Terezie; Strnad, Miroslav; Leubner-Metzger, Gerhard

2014-01-01

Roč. 111, č. 34 (2014), E3571-E3580 ISSN 0027-8424 R&D Projects: GA ČR GD522/08/H003; GA MŠk LK21306; GA MŠk(CZ) LO1204; GA ČR GA14-34792S Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional support: RVO:61389030 Keywords : dormancy gene DOG1 * gibberellin metabolism * germination temperature Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 9.674, year: 2014

Germination responses of Cañahua (Chenopodium pallidicaule Aellen) to temperature and sowing depth

DEFF Research Database (Denmark)

Rodriguez Calle, Juan Pablo; Jacobsen, Sven-Erik; Sørensen, Marten

2016-01-01

Cañahua (Chenopodium pallidicaule) is grown in the Altiplano of Bolivia and Peru, between 3810 and 4200 m a.s.l. Rural indigenous households have cultivated the cañahua as a subsistence crop for millennia. The seeds have a high content and quality of protein. We studied the relation between...... the following: (i) temperature and seed germination and (ii) the effect of temperature and sowing depth on seedling emergence of five cultivars and one landrace. Three experiments were conducted as follows: (i) seeds of a cultivar were germinated in Petri dishes at six temperatures (3, 5, 10, 14, 20 and 24 °C...... significantly effect on the germination percentages of the plants (P Seeds germinated at the lowest temperature (3 °C). The estimated base temperature was close to 0 °C. A polynomial function described well the relation between time to 50% germination (t50) and temperature in the interval from 3 to 24...

The effects of temperature and salinity on Acacia harpophylla (brigalow) (Mimosaceae) germination

Energy Technology Data Exchange (ETDEWEB)

Reichman, S.M.; Bellairs, S.M.; Mulligan, D.R. [Lincoln University, Lincoln (New Zealand). Division of Agriculture & Life Science

2006-07-01

Some coal mining companies in central Queensland have become interested in providing habitat for the endangered bridle nail-tailed wallaby that lives in brigalow vegetation. However, there is little known about establishment techniques for brigalow on mine sites and other disturbed ground; an understanding of brigalow biology and ecology is required to assist in the conservation of this threatened vegetation community and for re-creation of bridled nail-tail wallaby habitat in the post mining landscape. Brigalow is an unusual species of Acacia because it is not hard-seeded and germinates readily without the need to break seed-coat imposed dormancy. Germination trials were undertaken to test the ability of brigalow seed to germinate with a range of temperatures and salinity levels similar to those experienced in coal mine spoil. Optimum germination was found to occur at temperatures from 15 to 38{sup o}C and no germination was recorded at 45{sup o}C. Brigalow was very tolerant of high salt levels and germinated at percentages greater than 50% up to the highest salinity tested, 30 dS/m. Germination of greater than 90% occurred up to an electrical conductivity of 20 dS/m. The results indicate brigalow seed can be sown in summer when rains are most likely to occur; however, shading of the seed with extra soil or mulch may ensure the ground surface does not become too hot for germination. Because of its ability to germinate at high salinity levels, brigalow may be suitable for use in saline mine wastes which are common on sites to be rehabilitated after mining.

Temperature Effects on the Seed Germination of Some Perennial and Annual Species of Asteraceae Family

Directory of Open Access Journals (Sweden)

Zarghani Hadi

2014-12-01

Full Text Available Temperature is the most critical factor determining success or failure of plant establishment. Seed germination response of five medicinal species include three seed-propagated perennial species, Cichorium intybus, cynara scolymus and Echinacea purpurea and vegetative-reproduction perennial species, Achillea millefolium and annual species, Matricaria aurea were assessed at constant temperatures. The seeds were exposed to constant temperatures of 5, 10, 15, 20, 25, 30, 35, 40 and 45°C under total darkness. Germination percentage of all the species were significantly affected by various temperatures (p ≤ 0.001. A. millefolium did not germinate at 5-10 and 35-45°C, but showed noticeable germination percentage (73.3-100% at temperatures ranged from 15-30° C. The highest total germination percentage was observed within the range of 15-35 °C for other species. Also, we calculated cardinal temperatures (the minimum, optimum and maximum temperature for seed germination of species. The highest value for minimum temperature was 10.07ºC in A. millefolium followed by C. scolymus and M. aurea (5ºC while the lowest was for E. purpurea and C. intybus (2.68 and 2.90ºC respectively. The lowest value for optimum temperature was detected in A. millefolium (22.72ºC and M. aurea (23.88°C while the maximum values were observed in E. purpurea and C. intybus (30.40ºC and 29.90ºC respectively. Based on results of present study we concluded that species with both vegetative and seed-propagated reproduction forms like A. millefolium had smaller temperature range rather those with just one way of reproduction (seed production.

Effect of industrial pollution on seed germination

Energy Technology Data Exchange (ETDEWEB)

Iqbal, M.Z.; Qadir, S.A.

1973-01-01

The germination behavior of seeds in polluted waters and polluted soil extracts was found to be identical, only a few species behaved differently. Prosopis juliflora, Haloxylon recurvum, Acacia senegal showed best germination in the two conditions but Prosopis juliflora was the most resistant to pollution. In Suaeda fruticosa no germination took place in the control treatment whereas highest germination (70%) was seen in treatment with polluted soil extract of EPLA. Blepharis sindica showed a stimulating effect of polluted water on germination, whereas low germination was observed when their seeds were treated with the soil extract of the same site. 40% germination of Suaeda monoica was seen in polluted water of Carbon and Ribbon Mfg. Co., whereas 30% germination was found in a control treatment. Low percentage of germination was found when the seeds of Cassia holosericea were treated with polluted waters of different industries as compared to soil extract treatments of the same industries. Datura alba showed 50, 30 and 10% seed germination in polluted soil extract of Carbon and Ribbon Mfg. Co., in control and in polluted water of Darbar Soap Works, respectively. 5 references, 1 table.

Effect of light, temperature and different pretreatments on seed germination of gentiana boissieri schott et kotschy ex boiss. (gentianaceae) and endemic to turkey

International Nuclear Information System (INIS)

Erken, S.

2017-01-01

This study was undertaken with the aim of determining the germination characteristics of Gentiana boissieri (Gentianaceae), an endemic species. The effects of light, temperature and different pretreatments on the germination of seeds collected from nature were investigated. Two different experiments were run to determine germination characteristics of seeds and the final germination percentage (FGP), mean germination time (MGT) and germination index (GI). The first experiment involved twenty different treatments including soaking in water, soaking in gibberellic acid (GA3), dry stratification, moist cold stratification, moist warm stratification + moist cold stratification, moist cold stratification + soaking in GA3 and control. The germination test was carried out at +20 degree C in dark. The highest final germination percentages were obtained from the treatments of soaking in 500, 750, 1000 ppm GA3, soaking in 250, 500 ppm GA3 + 4 weeks of moist cold stratification (89.00; 95.00; 93.50; 91.33; 94.00%, respectively). In the control group with no pretreatment, the final germination percentage of seeds was found to be 13.50%. In the second experiment, seeds treated with 750 ppm GA3 pretreatment, providing highest germination rate in the first experiment, were germinated under dark and light conditions (12/12 h; dark/light) at 15, 20, 25 and 10/20 degree C. At the end of 28 days under four different temperatures, it was found that light significantly increased the final germination percentage and the highest final germination percentages were found at 15 and 20 degree C (87.00; 89.50%, respectively). (author)

Effect of X-ray irradiation on germination of rice and wheat at different temperatures and pH levels of water

International Nuclear Information System (INIS)

Rajput, T.B.S.; Singh, Jaswant

1981-01-01

An experiment was conducted on the germination of ''Jaya'' rice (Oryza sativa Linn.) and ''Sonalika'' wheat (Triticum aestivum Linn. emend. Thell.) to study the effects of low doses of X-ray irradiation at different temperatures and pH levels of water. The percentage of germination was more at pH 7, and decreased with an increase or decrease in pH level. In most of the cases irradiation delayed the germination and proved to be harmful. But at 20deg C, 4 KR X-ray irradiation promoted the germination of rice by more than 15% at pH levels of 5.5-8.5. But in wheat no significant increase in germination percentage was noted at any combination of the parameters. (auth.)

Specificity of germination of heteromorphic seeds in four annuals (Salsola L.) at different temperatures in the Junggar basin

International Nuclear Information System (INIS)

Ning, L.; Feng, L.H.; Chi, L.Z.; Xia, C.Z.

2015-01-01

Salsola L. is a large genus of arid desert plants that are primarily distributed in the Junggar Basin, China. We analysed their ability to adapt to arid habitats by comparing differences in germination characteristics of the species and populations of Salsola affinis C. A. Mey, Salsola korshinskyi Drob., Salsola brachiata Pall. and Salsola nitraria Pall. We classified the 4 species into four types (A, B, C and D) according to seed wing and seed size, and the heteromorphic seeds were incubatedunder different temperature regimes (0/10 degree C, 5/15 degree C, 10/25 degree C and 20/35 degree C). The 4 species had the highest germination rates and germination potential at 0/1 C. Germination rates and potential decreased with increasing temperature. However, the change range of the germination rate among the four species was different. Type A and B seeds of S. affinis, S. nitraria and S. korshinskyi were dominant at all temperatures and decreased with increasing temperature. The germination rate of type C seeds was between that of type A, B and D seeds. D-type seeds had the lowest germination rate and the lowest germination potential under the four temperature regimes among the four species but the differences were not significant. The germination rates of the four types of S. brachiata seeds did not significantly change with temperature. These results suggest that Salsola spp. can germinate continuously from spring to autumn to adapt to moisture fluctuations in the desert. (author)

Physiological potential of Oryza sativa seeds treated with growth regulators at low temperatures

Directory of Open Access Journals (Sweden)

Mara Grohs

Full Text Available ABSTRACT The rapid and uniform establishment of rice crops is important for improving production. However, this condition is influenced by several factors, including the soil temperature when planting, which may delay seed germination and compromise the final stand. The aim of this study was to evaluate the behaviour of substances which have the effect of growth regulator when applied to the seeds of different rice cultivars under low-temperature conditions. The experiment was carried out in a completely randomised design with four replications in a bi-factorial scheme, where factor A was represented by the different products (gibberellic acid - AG3, tiamethoxam - TMX, Haf Plus® - HAF, and a control with water - TEST, and factor B by the irrigated rice cultivars (IRGA 424, IRGA 425, Puitá INTA CL, and Avaxi CL. In addition, the experiment was repeated at temperatures of 17 °C and 25 °C in order to simulate low-temperature conditions. The results showed that AG3 is effective in increasing seed vigour in the rice cultivars at both temperatures, with the AG3, TMX and HAF responsible for increasing germination percentage only at the temperature of 17 °C. The effect of the products is more pronounced at low temperatures, and is dependent on the cultivar; in cultivars which are sensitive to cold there is no effect from the products used.

Factors Affecting the Germination of Akinetes of Nodularia spumigena (Cyanobacteriaceae)

OpenAIRE

Huber, Ann L.

1985-01-01

Nutritional and physical factors which influence the germination of akinetes of Nodularia spumigena (Cyanobacteriaceae) were examined. Low concentrations of phosphorus (45 μM, inhibited germination. Salinities of >20‰ were inhibitory to germination. Optimum temperatures were 22°C or greater. Germination did not take place in the dark, but only very low light intensities (0.5 microeinstein m−2 s−1) were necessary to initiate germination. Red light (620 to 665 nm) was required. More than 24 h o...

A Gusseted Thermogradient Table to Control Soil Temperatures for Evaluating Plant Growth and Monitoring Soil Processes.

Science.gov (United States)

Welbaum, Gregory E; Khan, Osamah S; Samarah, Nezar H

2016-10-22

Thermogradient tables were first developed in the 1950s primarily to test seed germination over a range of temperatures simultaneously without using a series of incubators. A temperature gradient is passively established across the surface of the table between the heated and cooled ends and is lost quickly at distances above the surface. Since temperature is only controlled on the table surface, experiments are restricted to shallow containers, such as Petri dishes, placed on the table. Welding continuous aluminum vertical strips or gussets perpendicular to the surface of a table enables temperature control in depth via convective heat flow. Soil in the channels between gussets was maintained across a gradient of temperatures allowing a greater diversity of experimentation. The gusseted design was evaluated by germinating oat, lettuce, tomato, and melon seeds. Soil temperatures were monitored using individual, battery-powered dataloggers positioned across the table. LED lights installed in the lids or along the sides of the gradient table create a controlled temperature chamber where seedlings can be grown over a range of temperatures. The gusseted design enabled accurate determination of optimum temperatures for fastest germination rate and the highest percentage germination for each species. Germination information from gradient table experiments can help predict seed germination and seedling growth under the adverse soil conditions often encountered during field crop production. Temperature effects on seed germination, seedling growth, and soil ecology can be tested under controlled conditions in a laboratory using a gusseted thermogradient table.

The effect of simulated heat-shock and daily temperature fluctuations on seed germination of four species from fire-prone ecosystems

Directory of Open Access Journals (Sweden)

Talita Zupo

2016-01-01

Full Text Available ABSTRACT Seed germination in many species from fire-prone ecosystems may be triggered by heat shock and/or temperature fluctuation, and how species respond to such fire-related cues is important to understand post-fire regeneration strategies. Thus, we tested how heat shock and daily temperature fluctuations affect the germination of four species from fire-prone ecosystems; two from the Cerrado and two from the Mediterranean Basin. Seeds of all four species were subjected to four treatments: Fire (F, temperature fluctuations (TF, fire+temperature fluctuations (F+TF and control (C. After treatments, seeds were put to germinate for 60 days at 25ºC (dark. Responses differed according to species and native ecosystem. Germination percentage for the Cerrado species did not increase with any of the treatments, while germination of one Mediterranean species increased with all treatments and the other only with treatments that included fire. Although the Cerrado species did not respond to the treatments used in this study, their seeds survived the exposure to heat shock, which suggests they possess tolerance to fire. Fire frequency in the Cerrado is higher than that in Mediterranean ecosystems, thus traits related to fire-resistance would be more advantageous than traits related to post-fire recruitment, which are widespread among Mediterranean species.

Effects of temperature, light and incubation period on production, germination and bioactivity of Trichoderma atroviride.

Science.gov (United States)

Daryaei, A; Jones, E E; Ghazalibiglar, H; Glare, T R; Falloon, R E

2016-04-01

The goal was to determine the effect of temperature, light and incubation period on production, germination and bioactivity of Trichoderma atroviride LU132 against Rhizoctonia solani. The incubation temperatures of 20, 25 or 30°C were assessed on the production of T. atroviride conidia under constant light over a 25 and 50 days periods. The resulting conidia were also studied for germination and bioactivity. Conidium production was maximum at 25°C after 20 days. The second peak of conidium production occurred at 45-50 days. Incubation at 25°C after 15 days showed optimum production of T. atroviride LU132. Conidia produced at 30°C gave the greatest germination and bioactivity in comparison with incubation at 20 or 25°C. This study indicates that the temperature at which conidia of T. atroviride are produced affects germination and bioactivity. Formulations based on production of the high conidia yield may not result in optimal bioactivity and there is a trade-off between quantity and quality of T. atroviride LU132 conidia. Conidium production was shown to be a continuous process, and increased under a dark/light regime. This is the first report of bimodal conidium production in a Trichoderma biological control agent (BCA), which is likely to be on 20 days cycle, and is dependent on colony age rather than abiotic factors. Conidia produced after 15 days are likely to be the most suitable for use in commercial production of this strain as a BCA. Most studies on Trichoderma-based BCA have only shown the effect of culture conditions on the high conidia yield regardless of conidium quality. This study is the first report on conidium quality affected by principal culture conditions for Trichoderma biological control formulations. © 2016 The Society for Applied Microbiology.

GERMINATION STUDIES ON Tabebuia impetiginosa Mart. SEEDS

Directory of Open Access Journals (Sweden)

Edvaldo Aparecido Amaral da Silva

2004-06-01

Full Text Available Seed germination and seedling production of native forest tree species are an important step in ex situ conservation programs and in the reforestation with ecological purposes. Therefore, understanding seed germination and its regulation is mandatory for the complete success of the conservation programs and revegetation techniques. Thus, morphological studies, temperature requirements for seed germination and its control by gibberellins (GAs were studied in Tabebuia impetiginosa (“ipê-roxo” seeds. The best temperature for germination under constant light was 30oC. The imbibition of T. impetiginosa seeds followed the common triphasic pattern, with most of the seeds attaining phase II at 24 hours and phase III at 72 hours of imbibition. Visible germination, as radicle elongation, started at 30 hours in water-imbibed seeds and at 24 hours in GA-imbibed seeds. Seeds imbibed in Paclobutrazol, an inhibitor of GA biosynthesis, failed to germinate. However, application of exogenous gibberellins overcame inhibition and allowed germination, suggesting that GAs are regulators of Tabebuia impetiginosa seed germination. The results suggested that germination in Tabebuia impetiginosa seeds is controlled by elongation of the radicle and gibberellins may play an important role in regulating it. The possible role of gibberellins is discussed.

Suicidal germination for parasitic weed control.

Science.gov (United States)

Zwanenburg, Binne; Mwakaboko, Alinanuswe S; Kannan, Chinnaswamy

2016-11-01

Parasitic weeds of the genera Striga and Orobanche spp. cause severe yield losses in agriculture, especially in developing countries and the Mediterranean. Seeds of these weeds germinate by a chemical signal exuded by the roots of host plants. The radicle thus produced attaches to the root of the host plant, which can then supply nutrients to the parasite. There is an urgent need to control these weeds to ensure better agricultural production. The naturally occurring chemical signals are strigolactones (SLs), e.g. strigol and orobanchol. One option to control these weeds involves the use of SLs as suicidal germination agents, where germination takes place in the absence of a host. Owing to the lack of nutrients, the germinated seeds will die. The structure of natural SLs is too complex to allow multigram synthesis. Therefore, SL analogues are developed for this purpose. Examples are GR24 and Nijmegen-1. In this paper, the SL analogues Nijmegen-1 and Nijmegen-1 Me were applied in the field as suicidal germination agents. Both SL analogues were formulated using an appropriate EC-approved emulsifier (polyoxyethylene sorbitol hexaoleate) and applied to tobacco (Nicotiana tabacum L.) fields infested by Orobanche ramosa L. (hemp broomrape), following a strict protocol. Four out of 12 trials showed a reduction in broomrape of ≥95%, two trials were negative, two showed a moderate result, one was unclear and in three cases there was no Orobanche problem in the year of the trials. The trial plots were ca 2000 m 2 ; half of that area was treated with stimulant emulsion, the other half was not treated. The optimal amount of stimulant was 6.25 g ha -1 . A preconditioning prior to the treatment was a prerequisite for a successful trial. In conclusion, the suicidal germination approach to reducing O. ramosa in tobacco fields using formulated SL analogues was successful. Two other options for weed control are discussed: deactivation of stimulants prior to action and

In vitro pollen germination of five citrus species

International Nuclear Information System (INIS)

Khan, S.A.; Perveen, A.

2014-01-01

The aim of present study is In vitro germination of the pollen grains of five Citrus species belonging to the family Rutaceae viz., Citrus aurantium L. var., aurantium Hook.f., C. limon (L.) Brum. f., C. paradisii Macfad, C. reticulata Blanco and C. sinensis (L.) Osbeck. using hanging drop technique. The germination was checked up to 48 weeks, for the pollen stored at different temperatures like 4 degree C, -20 degree C, -30 degree C and -60 degree C. The study indicates that low temperature and low relative humidity is better than high temperature and humidity with respect to pollen germination capacity and viability. Freeze dryer (-60 degree C) seems to be the best method to maintain pollen viability of stored pollen grains for a long period of time. Among five species Citrus aurantium, C. limon and C. sinensis showed high percentage of germination as compared to C. reticulata and C. paradisii. (author)

Seed colour affects light and temperature requirements during germination in two Lotus species (Fabaceae) of the Arabian subtropical deserts.

Science.gov (United States)

Bhatt, Arvind; Gairola, Sanjay; El-Keblawy, Ali A

2016-06-01

Heterogeneity in seeds mostly occurs due to physiological, environmental and genetic factors, and these could affect seed dormancy and germination. Therefore, the aim of our study was to assess the effect of seed colour on germination behavior. For this, both light and temperature requirements were assessed in Lotus glinoides and Lotus halophilus (Fabaceae) from the hyper-arid deserts of the United Arab Emirates. Germination was assessed in terms of both final germination level (percentage) and germination rate, as expressed by Timson’s germination velocity index. Lotus glinoides produces black and yellow-colored seeds, and L. halophilus produces green and yellow seeds. Different seed lots were germinated in both light and darkness at different temperatures. Yellow seeds of the two species attained significantly lower germination, compared to black and green seeds. There was no specific light or temperature requirements for the germination of the two coloured seeds of L. glinoides; the effect of interactions between seed colour and both light and incubation temperature, were not significant on the final germination percentage. In L. halophilus, green seeds germinated significantly more in both light and darkness at lower temperatures (15/25 °C) and in light at higher temperatures (25/35 °C), compared to yellow seeds. Yellow seeds germinated faster, compared to black at 15/25 °C in L. glinoides and compared to green seeds at 15/25 °C and 25/35 °C in L. halophilus. Seed colour variation, at least in L. halophilus, could be a survival strategy that would determine the time of germination throughout the year in the unpredictable desert environment.

The Effects of Temperature and Salinity on Germination and Seedling Growth Characteristics of Sesame (Sesamum indicum Landraces

Directory of Open Access Journals (Sweden)

E Izadi-Darbandi

2012-10-01

Full Text Available Seed germination is a crucial stage in the plant life cycle and salt tolerance during germination stage is vital for the establishment of plants in saline soils. In order to evaluation of sesame (Sesamum indicum landraces germination to salinity stress at different temperature, an experiment was conducted at Ferdowsi University of Mashhad, Collage of Agriculture during 2009. Experimental type was complete randomized design in factorial arrangement with 4 replications. Factors included salinity at 7 levels (0, -2, -3, -4, -6, -8, -10 and -12 bar, temperature at 3 levels (15°c, 20°c, 25°c and 3 sesame landraces (Sabzevar, Kalat and Oltan. Results showed that germination parameters (germination percentage, germination rate, root length, shoot length, dry weight of roots and dry weight of shoots in all landraces were significantly (p≤0.01 affected by salinity and temperature. Increasing salinity reduced all above parameters in sesame cultivars, so that highest tolerated dose of salt was obtained in 25°c and increasing of temperature reduced effects of salinity. The highest germination percent was observed in salinity between 0 to -4 bar at 25°c. Sabzevar and Oltan landraces exhibited the highest and the lowest indicators at different temperatures respectively. According to these results, it seems that in saline condition and temperature variation, Sabzevar is the appropriate sesame landraces for optimal seedling establishment.

Higher Temperature at Lower Elevation Sites Fails to Promote Acclimation or Adaptation to Heat Stress During Pollen Germination

Directory of Open Access Journals (Sweden)

Lluvia Flores-Rentería

2018-04-01

Full Text Available High temperatures associated with climate change are expected to be detrimental for aspects of plant reproduction, such as pollen viability. We hypothesized that (1 higher peak temperatures predicted with climate change would have a minimal effect on pollen viability, while high temperatures during pollen germination would negatively affect pollen viability, (2 high temperatures during pollen dispersal would facilitate acclimation to high temperatures during pollen germination, and (3 pollen from populations at sites with warmer average temperatures would be better adapted to high temperature peaks. We tested these hypotheses in Pinus edulis, a species with demonstrated sensitivity to climate change, using populations along an elevational gradient. We tested for acclimation to high temperatures by measuring pollen viability during dispersal and germination stages in pollen subjected to 30, 35, and 40°C in a factorial design. We also characterized pollen phenology and measured pollen heat tolerance using trees from nine sites along a 200 m elevational gradient that varied 4°C in temperature. We demonstrated that this gradient is biologically meaningful by evaluating variation in vegetation composition and P. edulis performance. Male reproduction was negatively affected by high temperatures, with stronger effects during pollen germination than pollen dispersal. Populations along the elevational gradient varied in pollen phenology, vegetation composition, plant water stress, nutrient availability, and plant growth. In contrast to our hypothesis, pollen viability was highest in pinyons from mid-elevation sites rather than from lower elevation sites. We found no evidence of acclimation or adaptation of pollen to high temperatures. Maximal plant performance as measured by growth did not occur at the same elevation as maximal pollen viability. These results indicate that periods of high temperature negatively affected sexual reproduction, such that

Effect of low dose irradiation of 60Co γ-rays on seed germination, seedling growth and enzymes activity of Lactuca sativa

International Nuclear Information System (INIS)

Liu Xiuqing; Zhang Tie

2012-01-01

The seeds of Lactuca sativa were irradiated by different doses (10, 20, 30, 40, 50 Gy) of 60 Co γ-rays. The effects of low dose irradiation on seed germination, seedling growth and enzymes activity were investigated. The results indicated that low dose irradiation could promote germination rate, germinating viability, germination rate in the field, root length and height of seedling. The suitable dosage for low dose irradiation for Lactuca sativa was 30 Gy. POD activity after irradiation treatment in the range of 10 to 50 Gy and CAT activity after irradiation treatment in the range of 20 Gy to 40 Gy was lower than that of control. (authors)

Weak Static and Extremely Low Frequency Magnetic Fields Affect In Vitro Pollen Germination

Directory of Open Access Journals (Sweden)

Lucietta Betti

2011-01-01

Full Text Available This study concerns the effects of a weak static magnetic field (MF at 10 μT oriented downward, combined with a 16-Hz sinusoidal MF (10 μT, on in vitro pollen germination of kiwifruit (Actinidia deliciosa. Extremely low frequency magnetic field (ELF-MF exposure was carried out by a signal generator unit connected to a copper wire solenoid, inside which samples where placed. Two different kinds of treatment were performed: direct and indirect. In the direct treatment, pollen samples were directly exposed during rehydration, germination, or both. In the indirect treatment, the pollen growth medium was prepared with water aliquots (at standard temperature of 20°C and pH = 6.74 that were exposed before use for 8 or 24 h. The main purpose of our research was to identify a biological marker (in vitro pollen germination in a stressing growth medium without Ca2+ susceptible to the effects of direct or indirect ELF-MF exposure. The working variable was the pollen germination rate, as detected blind after 3 h 30 min by an Axioplan microscope. A directionally consistent recovery of germination percentage was observed both for direct exposure (during germination and both rehydration and germination phases and water-mediated exposure (with water exposed for 24 h and immediately used. Our results suggest that the ELF-MF treatment might partially remove the inhibitory effect caused by the lack of Ca2+ in the culture medium, inducing a release of internal Ca2+ stored in the secretory vesicles of pollen plasma membrane. Although preliminary, findings seem to indicate the in vitro pollen performance as adequate to study the effects of ELF-MFs on living matter.

Effect of incubation temperature, seed age and scarification on germination and emergence of persian shallot

International Nuclear Information System (INIS)

Mohammadi, J.; Sabet, S.A.K.; Golshani, M.; Mortazavi, S.N.; Jafari, F.; Chirani, J.A.O.

2010-01-01

Persian shallot grows as a wild plant in some mountains of Iran, The aim of our research was to study the relationship between different temperatures, seed age and duration of sulfuric acid treatment on Persian shallot seed germination. The interactive effect of incubation temperature, seed age and scarification treatments had a significant effect on the germination and emergence percentage of Persian shallot. It is concluded that suitable condition for Persian shallot seed germination is scarification of one year old seeds with sulfuric acid for 15 min, and stratification at 4 deg. C. In fact Persian shallot seeds need both scarification and stratification for germination enhancement. (author)

A Modified Thermal Time Model Quantifying Germination Response to Temperature for C3 and C4 Species in Temperate Grassland

Directory of Open Access Journals (Sweden)

Hongxiang Zhang

2015-07-01

Full Text Available Thermal-based germination models are widely used to predict germination rate and germination timing of plants. However, comparison of model parameters between large numbers of species is rare. In this study, seeds of 27 species including 12 C4 and 15 C3 species were germinated at a range of constant temperatures from 5 °C to 40 °C. We used a modified thermal time model to calculate germination parameters at suboptimal temperatures. Generally, the optimal germination temperature was higher for C4 species than for C3 species. The thermal time constant for the 50% germination percentile was significantly higher for C3 than C4 species. The thermal time constant of perennials was significantly higher than that of annuals. However, differences in base temperatures were not significant between C3 and C4, or annuals and perennial species. The relationship between germination rate and seed mass depended on plant functional type and temperature, while the base temperature and thermal time constant of C3 and C4 species exhibited no significant relationship with seed mass. The results illustrate differences in germination characteristics between C3 and C4 species. Seed mass does not affect germination parameters, plant life cycle matters, however.

The Effect of Temperature and Water Potential on Seed Germination of Asian spiderflower (Cleome viscose L.: As Invasive Weed in Soybean Fields in Golestan Province

Directory of Open Access Journals (Sweden)

M. Shirdel

2016-09-01

Full Text Available Introduction: Cleome viscose Linn. with a common name as “Asian spiderflower”, belongs to the Capparidacea family. It is an annual, sticky herb found as a common weed all over the tropical regions of the world. It is a very competitive weed of annual crops. This plant is currently introduced as an invasive plant in soybean fields of Golestan province. There is no management recommendation to control Asian spider flower. Thus large quantities of soybean destroyed by this weed every year. Germination and emergence are the two most important stages in the life cycle of plants. Environmental factors such as temperature, light, pH, planting depth and soil moisture are known to affect seed germination and emergence of weeds. An understanding of the germination biology of Asian spider flower would facilitate the development of better management strategies for this weed. Therefore, the purposes of this research were to study the effects of temperature and water potential on Asian spider flower seed germination. Material and Methods: To evaluate the effect of temperature and water potential on seed germination and determination of seed germination cardinal temperatures of Asian spider flower, an experiment was conducted as Factorial Experiment in Completely Randomized Design with 4 replications in Agricultural Research and Natural Resources Center of Golestan Province during 2013. Treatments were included temperatures with seven levels (15, 20, 25, 30, 35, 38 and 400C and water potentials with six levels (0, -2, -4, -6, -8 and -10 bar. Germination was monitored daily until germination discontinued and the number of the germinated seeds was recorded. Seeds were observed twice daily and considered germinated when the radical was approximately >2mm long. To quantify the response of germination rate to temperature and to determine the cardinal temperatures for germination original beta, and modified beta, segmented and dent models were used. Water

EFFECTS OF PRE-GERMINATION TREATMENTS AND STORAGE ON GERMINATION OF Astronium fraxinifolium SCHOTT (ANACARDIACEAE DIASPORES

Directory of Open Access Journals (Sweden)

Lílian de Lima Braga

2014-06-01

Full Text Available http://dx.doi.org/10.5902/1980509814577The goal of this study was to evaluate the germination and the storage capacity of Astronium fraxinifolium diaspores. Six pre-germination treatments were used in the experiment: control treatment (intact diaspores; diaspores immersed in water at room temperature (25º C for 5 min; diaspores immersed in water at 70° C for 5 min; diaspores immersed in water at 100° C for 5 min; diaspores immersed in sodium hypochlorite solution (1:1000 for 2 min; and diaspores mechanically scarified with sandpaper #80. To evaluate storage conditions, we tested two different types of packaging (permeable paper bag and transparent glass jar and two environmental conditions (cold chamber and room conditions, resulting in four treatments. The germination tests were performed for zero (control and 60, 120, 180, 240, 300 and 360 days after storage. The effects of different treatments on germination and storage of diaspores were evaluated by ANOVA, followed by Tukey test. Regarding to pre-germination treatments, high germination rates were observed in the hypochlorite (98.0 ± 4.22%, control (97.0 ± 4.83%, water at room temperature (96.0 ± 6.99% and water at 70º C (83.0 ± 29.08% treatments. Thus, Astronium fraxinifolium diaspores do not present dormancy. During storage, the diaspores remained viable throughout the study period with high germination rates, except for the treatment in paper bags placed in the cold chamber, in which the diaspores lost their viability in the eighth month of storage. Therefore, this is not a recommended storage method for this species.

Salt stress and temperatures on the germination and initial growth of ‘jurema-de-embira’ (Mimosa ophthalmocentra seedlings

Directory of Open Access Journals (Sweden)

Narjara W. Nogueira

Full Text Available ABSTRACT The objective of this study was to evaluate the effects of salinity on the germination and initial growth of ‘jurema-de-embira’ (Mimosa ophthalmocentra seedlings at different temperatures. The experiment was installed in a completely randomized design, in a factorial scheme of eight salt concentrations (0; 4.0; 8.0; 12.0; 16.0; 20.0; 24.0 and 28.0 dS m-1 and four temperatures (25, 30, 35 and 20-30 °C in four replicates of 25 seeds under an 8-h photoperiod in Biochemical Oxygen Demand germinators. The variables analyzed were: germination, germination speed index, shoot and root lengths, and shoot, root and total dry matter. Temperature variation influences the response of ‘jurema-de-embira’ seeds to salinity, and the salt stress is intensified by the increase in temperature. ‘Jurema-de-embira’ is tolerant to salt stress in the germination stage, showing satisfactory germination up to the salinity level 20 dS m-1, at temperatures below 30 °C. The initial growth of ‘jurema-de-embira’ plants is satisfactory up to salinity of 12 dS m-1, at temperatures below 30 °C.

Effect of Temperature and Drought Stress on Germination of Slender Amaranth (Amaranthus viridis L. and Prostrate Pigweed (Amaranthus blitoides S. Watson Seeds

Directory of Open Access Journals (Sweden)

Marjan Diayanat

2018-02-01

effectively used to mimic drought stress with limited metabolic interferences as those associated to the use of low molecular weight. Over a 21d period, germination was studied in 5, 10, 15, 20, 25, 30, 35, 40 and 45°C constant temperatures and water potentials of 0, -0.2, -.04, -.06, -0.8 and -1.0 MPa. The number of 25 seeds were placed into petri dishes, then 10 ml of prepared drought solution was added to each petri dishe. Petri dishes, then, were placed in germinator in circadian alternation of 12 h light and 12 h darkness, under 9 temperatures and a relative humidity of 65 %. Data were statistically analyzed using analyses of variance in the SAS 9:1 software. Probabilities of significance were used to indicate significance among treatments and interaction effects. FLSD (p

Cold tolerance evaluation in Chilean rice genotypes at the germination stage

Directory of Open Access Journals (Sweden)

Gabriel Donoso Ñanculao

2013-03-01

Full Text Available Low temperature is the most important abiotic stress affecting rice (Oryza sativa L. yield in Chile. Rice in Chile is usually planted when the minimum air temperatures are below 12 °C. This temperature is lower than the optimum needed for normal rice germination. Therefore, the aim of this study was to evaluate cold tolerance in 20 experimental lines from the Rice Breeding Program of the Instituto de Investigaciones Agropecuarias (INIA, Chile, at the germination stage. Coleoptile length reduction (CRED, coleoptile length after cold treatment (CLEN, coleoptile length recovery (CREC, and coleoptile regrowth (CREG were evaluated at 13 °C for 4 d using 'Diamante-INIA' as the cold-tolerant control. To find genotypes with cold tolerance (low CRED value and high CLEN, CREC, and CREG values, genotypes were ranked, a biplot of principal components, and cluster analysis were performed. No differences were found among genotypes in the ranking based on CREC value so this trait was not considered. Analysis showed that only three experimental lines had cold tolerance similar to that of 'Diamante-INIA'; all other experimental lines exhibited intermediate to low cold tolerance. These results showed low cold tolerance of some Chilean genotypes at the germination stage, thus confirming the need to evaluate the rest of the germplasm from the Rice Breeding Program.

The Biological Effect of Extremely Low Frequency Electromagnetic Fields and Vibrations on Barley Seed Hydration and Germination

Directory of Open Access Journals (Sweden)

Armine Amyan

2004-01-01

Full Text Available The changes of wet and dry weights and germination of barley seed in different periods of its swelling in nontreated (control, extremely low frequency electromagnetic fields (ELF EMF –treated, and extremely low frequency vibrations (ELFV–treated cold (4°C and warm (20°C distilled water (DW were studied. The metabolic-dependent seed hydration, dry weight dissolving, germination, and water binding in seed were modulated by preliminary EMF- and ELFV-treated DW. Frequency “windows” for the effect of EMF and ELFV on seed hydration, solubility, water binding in seed, and germination were discovered. These “windows” were different for EMF and ELFV, as well as in various phases of seed swelling. It is suggested that EMF-induced water structure modification has a different biological effect on the process of seed hydration, solubility, water binding in seed, and germination compared to ELFV.

Seed germination response to high temperature and water stress in three invasive Asteraceae weeds from Xishuangbanna, SW China.

Science.gov (United States)

Yuan, Xia; Wen, Bin

2018-01-01

Crassocephalum crepidioides, Conyza canadensis, and Ageratum conyzoides are alien annuals naturalized in China, which produce a large number of viable seeds every year. They widely grow in Xishuangbanna, becoming troublesome weeds that compete with crops for water and nutrients. As seed germination is among the most important life-stages which contribute to plant distribution and invasiveness, its adaptation to temperature and water stress were investigated in these three species. Results showed that: (1) These three species have wide temperature ranges to allow seed germination, i.e., high germination and seedling percentages were achieved between 15°C and 30°C, but germination was seriously inhibited at 35°C; only A. conyzoides demonstrated relative preference for warmer temperatures with approximately 25% germination and seedling percentage at 35°C; (2) light was a vital germination prerequisite for C. crepidioides and A. conyzoides, whereas most C. canadensis seeds germinated in full darkness; (3) Although all three species have good adaptation to bare ground habitat characterized by high temperatures and water stress, including their tolerance to soil surface temperatures of 70°C in air-dried seeds, A. conyzoides seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 40°C, and to water restriction (e.g., ca. 65% seeds germinated to -0.8 MPa created by NaCl), which is consistent with their field behavior in Xishuangbanna. This study suggests that seed high-temperature tolerance contributes to the weed attributes of these three species, and that adaptation to local micro-habitats is a critical determinant for invasiveness of an alien plant.

Effect of temperature and salinity on germination of Achillea ...

African Journals Online (AJOL)

Achillea fragrantissima and Moringa peregrina are dominant plants in the mountainous desert of Saudi Arabia. The two species suffer from intensive anthropogenic pressures as they have important medicinal uses. This paper aimed to evaluate the effect of temperature and salinity on germination of A. fragrantissima and M.

Effect of different seed treatments on maize seed germination parameters under optimal and suboptimal temperature conditions

Directory of Open Access Journals (Sweden)

Vujošević Bojana

2017-01-01

Full Text Available The aim of this study was to determine the effect of different seed treatments on germination parameters of three maize genotypes under optimal and suboptimal temperature conditions. Seed was treated with recommended doses of three commercial pesticide formulations: metalaxyl-m 10 g/L + fludioxonil 25 g/L, metalaxyl 20 g/kg + prothioconazole 100 g/kg and thiacloprid 400 g/L. Testing was conducted at 25°C and 15°C. Results of the study indicate that there are differences in response of maize genotypes to applied seed treatments, as well as to a specific treatment at optimal and suboptimal temperatures. Some treatments, depending on the mixing partner and temperature conditions, can affect final germination. In other cases, germination rate can be accelerated or prolonged, but with no effect on final germination. In order to provide fast and uniform emergence under different temperature conditions, further examination of the response of maize genotypes to specific seed treatments would be beneficial.

Effects of salinity, temperature, light and dormancy regulating chemicals on seed germination of salsola drummondii ulbr

International Nuclear Information System (INIS)

Rasheed, A.; Hameed, A.; Khan, M.A.; Gul, B.

2015-01-01

Salsola drummondii Ulbr. is a perennial halophyte found in salt deserts of southern Balochistan, Pakistan. Experiments were conducted to study the effects of salinity (0, 200, 400, 600, 800 and 1000 mM NaCl), thermoperiod (10/20, 15/25, 20/30 and 25/35 degree C), light (12-h photoperiod and dark) and dormancy regulating chemicals (DRCs) on germination, recovery and viability of the seeds of S. drummondii. Seeds of S. drummondii germinated quickly in distilled water at different temperature regimes and increases in salinity decreased seed germination. Interestingly, few seeds could even germinate in 1000 mM NaCl treatment, which is about twice as high as seawater salinity. Seeds were partially photoblastic and showed relatively higher germination under 12-h photoperiod than in dark. Seeds showed poor recovery of germination from salinity and particularly when germinated in dark. Germination inhibition at high salinity (800 mM NaCl) under 12-h photoperiod was partially alleviated by the exogenous application of different DRCs, particularly fusicoccin. Moreover, all the DRCs, except GA4+7, ameliorated germination of salt stressed seeds under complete darkness and GA4 and fusicoccin were most effective. Our study shows that seeds of S. drummondii are highly tolerant to salinity and variation in temperature but partially photoblastic nature indicate that seeds will not germinate if buried under the soil. Seed germination under saline conditions can be improved by the use of DRCs particularly by application of fusicoccin. (author)

Comparison of the effects of temperature and water potential on seed germination of Fabaceae species from desert and subalpine grassland.

Science.gov (United States)

Hu, Xiao Wen; Fan, Yan; Baskin, Carol C; Baskin, Jerry M; Wang, Yan Rong

2015-05-01

Temperature and water potential for germination based on the thermal and hydrotime models have been successfully applied in predicting germination requirements of physiologically dormant seeds as well as nondormant seeds. However, comparative studies of the germination requirements of physically dormant seeds from different ecosystems have not been done. Germination of scarified seeds of four legume species collected from the Qing-Tibetan Plateau and of four collected in the Alax Desert in China was compared over a range of temperatures and water potentials based on thermal time and hydrotime models. Seeds of species from the Qing-Tibetan Plateau had a lower base temperature (T b) and optimal temperature (T o) for germination than those from the Alax Desert. Seeds of the four species from the Qing-Tibetan Plateau germinated to high percentages at 5°C, whereas none of the four desert species did so. Seeds of species from the Alax Desert germinated to a high percentage at 35°C or 40°C, while no seeds of species from the Qing-Tibetan Plateau germinated at 35°C or 40°C. The base median water potential [Ψ b(50)] differed among species but not between the two habitats. The thermal time and hydrotime models accurately predicted the germination time course of scarified seeds of most of the eight species in response to temperature and water potential; thus, they can be useful tools in comparative studies on germination of seeds with physical dormancy. Habitat temperatures but not rainfall is closely related to germination requirements of these species. © 2015 Botanical Society of America, Inc.

Hydrothermal germination models: Improving experimental efficiency by limiting data collection to the relevant hydrothermal range

Science.gov (United States)

Hydrothermal models used to predict germination response in the field are usually parameterized with data from laboratory experiments that examine the full range of germination response to temperature and water potential. Inclusion of low water potential and high and low-temperature treatments, how...

Seed vigor and germination of facheiro plants (Pilosocereus catingicola (Gurke Byles & Rowley Subsp. Salvadorensis (Werderm. Zappi (Cactaceae at different temperatures

Directory of Open Access Journals (Sweden)

Robson Luis Silva de Medeiros

2017-10-01

Full Text Available Several species of endemic Cactaceae are found in northeastern Brazil, which are important plants to the local fauna and flora; nevertheless, there are only a few studies assessing the germination of this plant genus. Understanding the germination of species native to the Caatinga is essential to subsidize conservation actions for such ecosystem. The objective of this study was to investigate the influence of three localities and different temperatures on the vigor and germination of facheiro seeds. The experiment was conducted by evaluating seed vigor and germination in three distinct areas (Arara, Bananeiras, and Boa Vista at different temperatures (20, 25, 30, 35, 40, and 20-30 ºC. Quantitative data were submitted to polynomial regression analysis at 5% significance with four replicates of 50 seeds. In Arara, germination rates at 20 and 25 ºC reached 96% and, at 30 ºC, 86%. The temperatures of 25 and 30 ºC presented the best germination speed index. For the three studied areas, the highest germination rates were recorded at a constant temperature of 25 ºC and at the alternating temperature (20-30 ºC. Yet the highest germination speed was reached at 30 ºC. Based on its sexual propagation, the taxon in question is able to survive in environments with temperatures ranging from 20 to 30 ºC, as seen in the studied habitats.

Modelling the effect of temperature on seed germination in some ...

African Journals Online (AJOL)

USER

2010-03-01

Mar 1, 2010 ... utilizes temperature for predicting seed germination and the model can be applied to ... seeds were sprinkled on round filter papers (Watman No. 1) in a 9 cm Petri dish and ..... A review of research on seedbed preparation for ...

Effect of temperature and substrate on germination of Peltophorum dubium (Sprengel Taubert seeds - doi: 10.4025/actascibiolsci.v33i1.7057 Effect of temperature and substrate on germination of Peltophorum dubium (Sprengel Taubert seeds - doi: 10.4025/actascibiolsci.v33i1.7057

Directory of Open Access Journals (Sweden)

Mácio Faria de Moura

2011-02-01

Full Text Available Peltophorum dubium (Spreng. Taub. is a species belonging to the family Fabaceae, and is known popularly as golden shower tree. Its wood has multiple uses in reforestation programs and as an ornamental tree, and is also considered an endangered species, requiring studies that assist in its preservation. The present work was conducted with the objective of determine the ideal substrate type and temperature to perform germination and vigor tests with P. dubium seeds. The experiment was carried out at the Seed Analysis Laboratory (Centro de Ciências Agrárias, Universidade Federal Paraíba, Areia, Paraíba, Brazil, in a completely randomized design. The treatments were distributed in a 4 x 6 factorial scheme; temperatures (constant temperatures of 25, 30 and 35°C; and alternate temperatures of 20-30°C and substrate (paper towel, over blotting paper, in sand, in vermiculite, Bioplant® and Plantmax® on four replications of 25 seeds. The following parameters were analyzed: germination percentage, germination speed index, first germination count, length and dry mass of seedlings. The constant temperature of 30°C and 20-30°C alternate, and the substrates into sand and paper towel can be recommended for germination and vigor tests of P. dubium seeds. The temperature of 25°C should not be used in germination and vigor tests of P. dubium seeds in any of the tested substrates.Peltophorum dubium (Spreng. Taub. is a species belonging to the family Fabaceae, and is known popularly as golden shower tree. Its wood has multiple uses in reforestation programs and as an ornamental tree, and is also considered an endangered species, requiring studies that assist in its preservation. The present work was conducted with the objective of determine the ideal substrate type and temperature to perform germination and vigor tests with P. dubium seeds. The experiment was carried out at the Seed Analysis Laboratory (Centro de Ciências Agrárias, Universidade Federal

Effets de dix traitements sur la germination des akènes d'Ambrosia maritima L

Directory of Open Access Journals (Sweden)

Schafer, JL.

1989-01-01

Full Text Available Effects of ten treatments on the germination of Ambrosia maritima L. seeds. Stratification of Ambrosia maritima seeds at + 10°C for 7 days appeared to be the best practical method to break their embryonic dormancy with 80 % germination occuring 18 days following the treatment, compared to 17 % for the control. This experiment confirms the susceptibility of embryonic dormancy to low temperatures. Treatments with waterat + 80°C or concentrated H2S04 for 15 mn and mechanical treatments eliminating the inhibition effect of seed integuments also gave higher results (43 to 53 % germination rate. However, germination in the control group was significantly higher than in the group of seeds subjected to dry heat. Although the first results obtained on the field from these trials were satisfactory, further research is needed to confirm them.

Seedling Emergence and Phenotypic Response of Common Bean Germplasm to Different Temperatures under Controlled Conditions and in Open Field.

Science.gov (United States)

De Ron, Antonio M; Rodiño, Ana P; Santalla, Marta; González, Ana M; Lema, María J; Martín, Isaura; Kigel, Jaime

2016-01-01

Rapid and uniform seed germination and seedling emergence under diverse environmental conditions is a desirable characteristic for crops. Common bean genotypes (Phaseolus vulgaris L.) differ in their low temperature tolerance regarding growth and yield. Cultivars tolerant to low temperature during the germination and emergence stages and carriers of the grain quality standards demanded by consumers are needed for the success of the bean crop. The objectives of this study were (i) to screen the seedling emergence and the phenotypic response of bean germplasm under a range of temperatures in controlled chamber and field conditions to display stress-tolerant genotypes with good agronomic performances and yield potential, and (ii) to compare the emergence of bean seedlings under controlled environment and in open field conditions to assess the efficiency of genebanks standard germination tests for predicting the performance of the seeds in the field. Three trials were conducted with 28 dry bean genotypes in open field and in growth chamber under low, moderate, and warm temperature. Morpho-agronomic data were used to evaluate the phenotypic performance of the different genotypes. Cool temperatures resulted in a reduction of the rate of emergence in the bean genotypes, however, emergence and early growth of bean could be under different genetic control and these processes need further research to be suitably modeled. Nine groups arose from the Principal Component Analysis (PCA) representing variation in emergence time and proportion of emergence in the controlled chamber and in the open field indicating a trend to lower emergence in large and extra-large seeded genotypes. Screening of seedling emergence and phenotypic response of the bean germplasm under a range of temperatures in controlled growth chambers and under field conditions showed several genotypes, as landraces 272, 501, 593, and the cultivar Borlotto, with stress-tolerance at emergence, and high yield

Seedling Emergence and Phenotypic Response of Common Bean Germplasm to Different Temperatures under Controlled Conditions and in Open Field

Directory of Open Access Journals (Sweden)

Antonio M. DE RON

2016-08-01

Full Text Available Rapid and uniform seed germination and seedling emergence under diverse environmental conditions is a desirable characteristic for crops. Common bean genotypes (Phaseolus vulgaris L. differ in their low temperature tolerance regarding growth and yield. Cultivars tolerant to low temperature during the germination and emergence stages and carriers of the grain quality standards demanded by consumers are needed for the success of the bean crop. The objectives of this study were i to screen the seedling emergence and the phenotypic response of bean germplasm under a range of temperatures in controlled chamber and field conditions to display stress-tolerant genotypes with good agronomic performances and yield potential, and ii to compare the emergence of bean seedlings under controlled environment and in open field conditions to assess the efficiency of genebanks standard germination tests for predicting the performance of the seeds in the field. Three trials were conducted with 28 dry bean genotypes in open field and in growth chamber under low, moderate and warm temperature. Morpho-agronomic data were used to evaluate the phenotypic performance of the different genotypes. Cool temperatures resulted in a reduction of the rate of emergence in the bean genotypes, however, emergence and early growth of bean could be under different genetic control and these processes need further research to be suitably modeled. Nine groups arose from the Principal Component Analysis (PCA representing variation in emergence time and proportion of emergence in the controlled chamber and in the open field indicating a trend to lower emergence in large and extra-large seeded genotypes. Screening of seedling emergence and phenotypic response of the bean germplasm under a range of temperatures in controlled growth chambers and under field conditions showed several genotypes, as landraces 272, 501, 593 and the cultivar Borlotto, with stress-tolerance at emergence and high

ABA-dependent inhibition of the ubiquitin proteasome system during germination at high temperature in Arabidopsis.

Science.gov (United States)

Chiu, Rex Shun; Pan, Shiyue; Zhao, Rongmin; Gazzarrini, Sonia

2016-12-01

During germination, endogenous and environmental factors trigger changes in the transcriptome, translatome and proteome to break dormancy. In Arabidopsis thaliana, the ubiquitin proteasome system (UPS) degrades proteins that promote dormancy to allow germination. While research on the UPS has focused on the identification of proteasomal substrates, little information is known about the regulation of its activity. Here we characterized the activity of the UPS during dormancy release and maintenance by monitoring protein ubiquitination and degradation of two proteasomal substrates: Suc-LLVY-AMC, a well characterized synthetic substrate, and FUSCA3 (FUS3), a dormancy-promoting transcription factor degraded by the 26S proteasome. Our data indicate that proteasome activity and protein ubiquitination increase during imbibition at optimal temperature (21°C), and are required for seed germination. However, abscisic acid (ABA) and supraoptimal temperature (32°C) inhibit germination by dampening both protein ubiquitination and proteasome activity. Inhibition of UPS function by high temperature is reduced by the ABA biosynthesis inhibitor, fluridone, and in ABA biosynthetic mutants, suggesting that it is ABA dependent. Accordingly, inhibition of FUS3 degradation at 32°C is also dependent on ABA. Native gels show that inhibition of proteasome activity is caused by interference with the 26S/30S ratio as well as free 19S and 20S levels, impacting the proteasome degradation cycle. Transfer experiments show that ABA-mediated inhibition of proteasome activity at 21°C is restricted to the first 2 days of germination, a time window corresponding to seed sensitivity to environmental and ABA-mediated growth inhibition. Our data show that ABA and high temperature inhibit germination under unfavourable growth conditions by repressing the UPS. © 2016 The Authors The Plant Journal © 2016 John Wiley & Sons Ltd.

Germination of tropical forage seeds stored for six years in ambient and controlled temperature and humidity conditions in Thailand

Directory of Open Access Journals (Sweden)

Michael D. Hare

2018-01-01

Full Text Available The germination performances of fresh seed lots were determined for 5 tropical forage species: Mulato II hybrid brachiaria [Urochloa ruziziensis (syn. Brachiaria ruziziensis x U. decumbens (syn. B. decumbens x U. brizantha (syn. B. brizantha], Mombasa guinea [Megathyrsus maximus (syn. Panicum maximum], Tanzania guinea [M. maximus (syn. P. maximum], Ubon paspalum (Paspalum atratum and Ubon stylo (Stylosanthes guianensis, stored under ambient conditions in Thailand (mean monthly temperatures 23‒34 ºC; mean monthly relative humidity 40‒92% or in a cool room (18‒20 ºC and 50% relative humidity for up to 6 years. The first paper of this study showed all seeds, except unscarified Ubon stylo seed, were dead after a single year of storage in ambient conditions. This second paper shows that cool-room storage extended seed viability, but performance varied considerably between species. Germination percentage under laboratory conditions declined to below 50%, after 3 years storage for Mombasa guinea seed and Tanzania guinea seed, 4 years for Ubon paspalum seed and 4‒5 years for Mulato II seed. Ubon stylo seed maintained high germination for 5 years, in both cool-room storage (96% and ambient-room storage (84%. Apparent embryo dormancy in acid-scarified Mulato II seed steadily increased with time in cool-storage and this seed had to be acid-scarified again each year at the time of germination testing to overcome dormancy. Physical dormancy of Mulato II seeds, imposed by the tightly bound lemma and palea in unscarified seed, was not overcome by length of time in cool-storage and these seeds had to be acid-scarified to induce germination. Hardseeded percentage in Ubon stylo seed remained high throughout the study and could be overcome only by acid-scarification. The difficulties of maintaining acceptable seed germination percentages when storing forage seeds in the humid tropics are discussed.

Germination and vigor of linseed seeds under different conditions of light, temperature and water stress

Directory of Open Access Journals (Sweden)

Raquel Stefanello

2017-06-01

Full Text Available Linseed (Linum usitatissimum L., cultivated from seeds, is one of the oldest plants domesticated by humans and is popularly used as a medicine. It can be used as the raw material to produce oil and bran because it has high lipids content, fiber and proteins. Based on the economic potential of this species and the need for more information about its physiology, the goal of this study was to analyze the effects of light, temperature and water stress on the germination and vigor of linseed seeds. In experiment I the seeds were sown on paper at constant temperatures of 15, 20, 25 and 30 ºC in the presence and absence of light. In experiment II, the seeds were placed on paper germitest soaked in solutions of polyethylene glycol (PEG 6000 at osmotic potentials corresponding to zero, -0.10, -0.20, -0.30, -0.40, -0.50 and -0.60 MPa. To evaluate the physiological potential, the following tests were made: germination, first germination count, length and dry mass of seedlings, and water stress. It was found that the highest percentages of germination and vigor occurred at a constant temperature of 20 °C, both in the presence and absence of light. The reduction of the osmotic potential of the substrate promoted a significant decrease in the germination and vigor of the linseed seeds. Osmotic potentials equal or less than -0.30 MPa were harmful to germination and there was no normal seedling development starting at -0.50 MPa.

Pre-treating Seed to Enhance Germination of Desert Shrubs

Energy Technology Data Exchange (ETDEWEB)

W. K. Ostler; D. C. Anderson; D. J. Hansen

2002-06-01

Creosotebush [Larrea tridentata (D.C.) Cav.] and white bursage [Ambrosia dumosa (A. Gray) W.W. Payne] seeds were subjected to pre-treatments of rinsing and soaking in water and thiourea to enhance germination in laboratory experiments. The effects of darkness, temperature, seed source, and soil moisture were also evaluated in the laboratory. The best pre-treatment from the laboratory experiments, rinsing with water for 36 hours followed by drying, was field-tested at Fort Irwin, California. Two sites and two seeding dates (early March and mid April) were determined for each site. Five mulch treatments (no mulch, straw, gravel, chemical stabilizer, and plastic) were evaluated in combination with the seed pre-treatments. Field emergence was greatly enhanced with the seed pre-treatment for white bursage during the March (18-42% increase in germination) and April seedings (16-23% increase in germination). Creosotebush showed poor germination during March (2-5%) when soil temperatures averaged 15 C, but germination increased during the April trials (6-43%) when soil temperatures averaged 23 C. The seed pre-treatment during the April trials increased germination from 16-23%. The plastic mulch treatment increased germination dramatically during both the March and April trials. The plastic mulch increased soil temperatures (8-10 C)and maintained high humidity during germination. Both the chemical stabilizer and the gravel mulches improved germination over the control while the straw mulch decreased germination. These results suggest that seed pre-treatments combined with irrigation and mulch are effective techniques to establish these two dominant Mojave Desert species from seed.

Ecological implications and environment dependence of the seed germination of common species in cold deserts

International Nuclear Information System (INIS)

Yuan, S.Y.; Tong, L.; Chi, L.Z.

2016-01-01

Vegetation is increasingly affected by climate change in cold deserts. Nonetheless, research is limited regarding the natural environmental demands of seed germination in such deserts. This study was conducted in Gurbantunggut Desert as a research base and 17 common species as subjects to investigate the moisture and temperature needs of seed germination in artificial settings, as well as the relationship between characteristics of seed germination and the local distribution of dune and shrubs. Results showed:(1) all tested species generally display low germination percentages that range between 2.9% and 79.6%. Winter snow melt dictates seed germination in cold deserts. Moreover, the subsequent spring rainfall can increase the survival rate of seedlings and significantly affect the process of seed germination. (2) seeds start to germinate only two days after snow melts at the average daily temperature (day/night) of 3.5 degree C (6.7 degree C/-0.5 degree C) and at a soil volumetric water content of 24.2%. Fifteen days after snow melt, all species germinate when the soil volumetric water content is 6.0% and the average daily temperature is 12.9 degree C (18.3 degree C/7.1 degree C). (3) The seed germination of the tested species can be divided into four patterns: rapid, transitional, slow, and low. Low-pattern plants mainly grow on upper dunes and are significantly associated with shrubs. Rapid- and slow-pattern plants distribute in middle and lower dunes. A few of these plants are significantly associated with shrubs. Transitional-pattern plants generally develop in the low land between hills and middle dunes. This study provides a reference for the actual environmental needs of seed germination in cold deserts and for the temperature and moisture requirements of this process in future experimental settings. (author)

The effect of temperature on the germination of Melocactus violaceus Pfeiff. (Cactaceae, a threatened species in restinga sandy coastal plain of Brazil

Directory of Open Access Journals (Sweden)

LUIZ R. ZAMITH

2013-06-01

Full Text Available Melocactus violaceus is an endangered species due to habitat destruction and the overcollection of this species for ornamental use. The aim of this study was to test the effect of different temperatures on the germination of M. violaceus. Three treatments were conducted: a constant temperature of 25ºC, a 20-35ºC alternating temperature, both inside germination chamber, and an alternating temperature under room temperature (mean temperature ranged from 25-37ºC. The final seed germination rates at the alternating temperature treatments were not significantly different (65% in the seed germinator and 62.5% at room condition. However, both treatments with alternating temperatures had significantly higher germination rates compared to the treatment kept at the constant temperature (8%. Our study showed that alternating temperatures between 20 and 37ºC provides satisfactory conditions to induce a high percentage of seed germination of M. violaceus, without the passage of seeds through the digestive tract of its natural disperser, the lizard Tropidurus torquatus. This condition contributes to efficiently producing seedlings that can be reintroduced into conservation areas or used as ornamentals that may help reduce the overcollection of the remaining native populations.

The effect of temperature on the germination of Melocactus violaceus Pfeiff. (Cactaceae), a threatened species in restinga sandy coastal plain of Brazil.

Science.gov (United States)

Zamith, Luiz R; Cruz, Denise D; Richers, Bárbara T T

2013-01-01

Melocactus violaceus is an endangered species due to habitat destruction and the overcollection of this species for ornamental use. The aim of this study was to test the effect of different temperatures on the germination of M. violaceus. Three treatments were conducted: a constant temperature of 25ºC, a 20-35ºC alternating temperature, both inside germination chamber, and an alternating temperature under room temperature (mean temperature ranged from 25-37ºC). The final seed germination rates at the alternating temperature treatments were not significantly different (65% in the seed germinator and 62.5% at room condition). However, both treatments with alternating temperatures had significantly higher germination rates compared to the treatment kept at the constant temperature (8%). Our study showed that alternating temperatures between 20 and 37ºC provides satisfactory conditions to induce a high percentage of seed germination of M. violaceus, without the passage of seeds through the digestive tract of its natural disperser, the lizard Tropidurus torquatus. This condition contributes to efficiently producing seedlings that can be reintroduced into conservation areas or used as ornamentals that may help reduce the overcollection of the remaining native populations.

Seed after-ripening and dormancy determine adult life history independently of germination timing.

Science.gov (United States)

de Casas, Rafael Rubio; Kovach, Katherine; Dittmar, Emily; Barua, Deepak; Barco, Brenden; Donohue, Kathleen

2012-05-01

• Seed dormancy can affect life history through its effects on germination time. Here, we investigate its influence on life history beyond the timing of germination. • We used the response of Arabidopsis thaliana to chilling at the germination and flowering stages to test the following: how seed dormancy affects germination responses to the environment; whether variation in dormancy affects adult phenology independently of germination time; and whether environmental cues experienced by dormant seeds have an effect on adult life history. • Dormancy conditioned the germination response to low temperatures, such that prolonged periods of chilling induced dormancy in nondormant seeds, but stimulated germination in dormant seeds. The alleviation of dormancy through after-ripening was associated with earlier flowering, independent of germination date. Experimental dormancy manipulations showed that prolonged chilling at the seed stage always induced earlier flowering, regardless of seed dormancy. Surprisingly, this effect of seed chilling on flowering time was observed even when low temperatures did not induce germination. • In summary, seed dormancy influences flowering time and hence life history independent of its effects on germination timing. We conclude that the seed stage has a pronounced effect on life history, the influence of which goes well beyond the timing of germination. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

TIME REDUCTION FOR SURINAM GRASS SEED GERMINATION TEST

Directory of Open Access Journals (Sweden)

Camila de Aquino Tomaz

2015-10-01

Full Text Available ABSTRACTThe period for the germination test of Surinam grass seeds established by the Rules for Seeds Testing is 28 days, considered too lengthy by producers, venders, and seed analysis laboratories. So, the objective of this research was to evaluate the possibility of reducing the time for the germination test of Surinam grass seeds and to establish a method for dormancy breaking and the ideal temperature. Ten seed lots were submitted to the following treatments to overcome seed dormancy: control; substrate moistening with 0.2% KNO3; and scarification with sulfuric acid (98% 36 N for 15 minutes. After the treatments, the lots were submitted to seed water content, germination and tetrazolium tests. During the germination test, conducted with four replicates of 100 seeds per treatment for 28 days, two conditions of alternating temperatures (20-35 °C and 15-35 °C with 8 hours of light were tested. Attempting to determine the test end date, daily counts of the number of normal seedlings were made and for each lot, treatment, and temperature, a growth curve for the evaluation of germination was adjusted. The segmented regression model parameter estimations were calculated for each treatment. The germination test of Braquiaria decumbensseeds may be evaluated in 12 days after sowing using alternating temperatures of 20-35 °C and without any treatment to overcome dormancy.

Ecophysiology of seed germination in Digitaria insularis ((L. Fedde

Directory of Open Access Journals (Sweden)

Giovana Soares de Mendonça

Full Text Available The invasive behaviour of sourgrass (Digitaria insularis in cultivated areas is due to its strategy of aggressive regeneration, which is based on seed germination. Knowledge of the physiological ecology of this species can contribute to the development of management and control strategies. The aim of this research was to understand the effects of provenance, temperature and light on the germination of sourgrass seeds collected in the Brazilian state of São Paulo in the cities of Americana, Botucatu and São José do Rio Preto and in the state of Paraná in the city of São Miguel do Iguaçu. The seeds were left to germinate at temperatures of 15, 25, 35 and 45 °C, both with and without light. The number of normal seedlings was recorded daily from seven to 60 days. After this period, the seeds together with substrate, were transferred to 25 ºC with light, and a daily count was made for all treatments until the end of germination (75 days after sowing. The seeds of D. insularis are positively photoblastic. Seed germination in this species depends on provenance. A temperature of 4 5 °C for germination is lethal to the seeds. The temperature of 35 °C in the presence of light is the most favourable condition for seed germination.

Microorganisms control during processing of germinated brown rice

International Nuclear Information System (INIS)

Suzuki, K.; Maekawa, T.

1999-01-01

In order to limit the growth of microorganisms during processing of germinated brown rice (GBR), three kinds of operations for sanitation control were investigated. For a surface-disinfection treatment of brown rice, soaking in 1% of sodium hypochlorite for 10min. and 0.1% of calcium preparation solutions for 10min. at 30°C, resulted in 2log decrease by aerobic plate count in culture water after 1h of the germination processing. Soaking in 10% of sodium hypochlorite for 10min. and 1% of calcium preparation solutions for 10min at 30°C were found to inhibit germination, respectively. During the germination processing, including aeration stage and non-aeration stage, continuous ultraviolet irradiation on the culture water in the water tank resulted in limited bacterial growth in culture water below 102CFU/ml by aerobic plate count. Moreover, the turbidity of the culture water was improved by filtration of the stored water using activated carbon-hollow fiber filter. The filtration by activated carbon-hollow fiber filter during the germination processing was an effective method to eliminate microorganisms and contamination factor during GBR production. It also improved the efficiency of ultraviolet irradiation effect on the culture water

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.

Genetic Variation for Thermotolerance in Lettuce Seed Germination Is Associated with Temperature-Sensitive Regulation of ETHYLENE RESPONSE FACTOR1 (ERF1)1[OPEN

Science.gov (United States)

O’Brien, Laurel K.; Truco, Maria Jose; Huo, Heqiang; Sideman, Rebecca; Hayes, Ryan; Michelmore, Richard W.

2016-01-01

Seeds of most lettuce (Lactuca sativa) cultivars are susceptible to thermoinhibition, or failure to germinate at temperatures above approximately 28°C, creating problems for crop establishment in the field. Identifying genes controlling thermoinhibition would enable the development of cultivars lacking this trait and, therefore, being less sensitive to high temperatures during planting. Seeds of a primitive accession (PI251246) of lettuce exhibited high-temperature germination capacity up to 33°C. Screening a recombinant inbred line population developed from PI215246 and cv Salinas identified a major quantitative trait locus (Htg9.1) from PI251246 associated with the high-temperature germination phenotype. Further genetic analyses discovered a tight linkage of the Htg9.1 phenotype with a specific DNA marker (NM4182) located on a single genomic sequence scaffold. Expression analyses of the 44 genes encoded in this genomic region revealed that only a homolog of Arabidopsis (Arabidopsis thaliana) ETHYLENE RESPONSE FACTOR1 (termed LsERF1) was differentially expressed between PI251246 and cv Salinas seeds imbibed at high temperature (30°C). LsERF1 belongs to a large family of transcription factors associated with the ethylene-signaling pathway. Physiological assays of ethylene synthesis, response, and action in parental and near-isogenic Htg9.1 genotypes strongly implicate LsERF1 as the gene responsible for the Htg9.1 phenotype, consistent with the established role for ethylene in germination thermotolerance of Compositae seeds. Expression analyses of genes associated with the abscisic acid and gibberellin biosynthetic pathways and results of biosynthetic inhibitor and hormone response experiments also support the hypothesis that differential regulation of LsERF1 expression in PI251246 seeds elevates their upper temperature limit for germination through interactions among pathways regulated by these hormones. Our results support a model in which LsERF1 acts through

Effects of Occurrence of Drought Stress in Maternal Environment on Cardinal Temperatures and Germination Responses of Carthamus Species

Directory of Open Access Journals (Sweden)

Mohammad Reza Nazari

2018-02-01

Full Text Available Safflower (Carthamustinctorius L. is one of the oldest domesticated crops, mainly grown as an oilseed in the arid and semiarid regions of the world. This study was conducted to investigate the Cardinal temperatures and to identify the effects of occurrence of drought stress in maternal environment on seed germination aspects of some Carthamus species according to a completely randomized design in 2014. To accomplish this, seeds of 13 genotypes from C. tinctorius, C. palaestinus, C. oxyacanthus, C. glaucus and C. lanatus were used which had been harvested from plants grown at normal and drought stress conditions. Seeds were subjected to 9 fixed temperatures (5, 10, 15, 20, 25, 30, 35, 40 and 45°C for germination in the growth chamber according to a factorial experiment. Results showed that the effects of genotype, species, temperature, pretreatment drought stress and some of their interactions were significant for certain germination characteristics at 0.05% probability level. Significant reductions occurred in the germination rate of seeds at temperatures below 10°C and above 30°C. Although there were significant differences in percent of seed germination among species, seeds harvested from drought stressed plants were not significantly different from the ones harvested from non-stressed plants in terms of cardinal temperatures. Hence, it is more likely that cardinal temperatures will not cause difficulties in the case of inter-specific breeding programs for drought tolerant safflower cultivar development.

Seed dormancy and germination changes of snowbed species under climate warming: the role of pre- and post-dispersal temperatures

Science.gov (United States)

Bernareggi, Giulietta; Carbognani, Michele; Mondoni, Andrea; Petraglia, Alessandro

2016-01-01

Background and Aims Climate warming has major impacts on seed germination of several alpine species, hence on their regeneration capacity. Most studies have investigated the effects of warming after seed dispersal, and little is known about the effects a warmer parental environment may have on germination and dormancy of the seed progeny. Nevertheless, temperatures during seed development and maturation could alter the state of dormancy, affecting the timing of emergence and seedling survival. Here, the interplay between pre- and post-dispersal temperatures driving seed dormancy release and germination requirements of alpine plants were investigated. Methods Three plant species inhabiting alpine snowbeds were exposed to an artificial warming treatment (i.e. +1·5 K) and to natural conditions in the field. Seeds produced were exposed to six different periods of cold stratification (0, 2, 4, 8, 12 and 20 weeks at 0 °C), followed by four incubation temperatures (5, 10, 15 and 20 °C) for germination testing. Key Results A warmer parental environment produced either no or a significant increase in germination, depending on the duration of cold stratification, incubation temperatures and their interaction. In contrast, the speed of germination was less sensitive to changes in the parental environment. Moreover, the effects of warming appeared to be linked to the level of (physiological) seed dormancy, with deeper dormant species showing major changes in response to incubation temperatures and less dormant species in response to cold stratification periods. Conclusions Plants developed under warmer climates will produce seeds with changed germination responses to temperature and/or cold stratification, but the extent of these changes across species could be driven by seed dormancy traits. Transgenerational plastic adjustments of seed germination and dormancy shown here may result from increased seed viability, reduced primary and secondary dormancy state, or both, and

Germination and seedling morphology of four South American Smilax (Smilacaceae

Directory of Open Access Journals (Sweden)

Aline Redondo Martins

2012-03-01

Full Text Available Species of Smilax, also known as greenbrier, are widely distributed in Brazil and their commercial trades are carried out by the extractivism of native species. We the aim to provide information about the germination and development of seedlings in four Smilax species, different experiments were developed under controlled conditions. We evaluated two germination treatments: temperature (30ºC and 20-30ºC and light (presence/ absence, and for few cases the tetrazolium treatment was applied. A different treatment response was observed among the studied species. Light had a significant influence in S. brasiliensis, with the highest germination rates at 20-30ºC in dark conditions. S. campestris showed significant differences among temperature treatments, but not to light; while S. cissoides showed high germination rates (66-78%, independently of treatment. However, S. polyantha had low germination rates (19-24%. After one year, the expanded leaves showed different characteristics among the studied species. Leaves of S. brasiliensis were ovate, coriaceous, three main veins and prickle-like structures only on the midrib on abaxial face. S. campestris leaves were oblong, coriaceous and prickle-like structures were located at the leaf midrib and margin. S. cissoides had ovate-elliptic, membranaceous leaves, with three main veins with prickle-like structures on the abaxial face. S. polyantha leaves showed ovateelliptic, coriaceous leaves, with three main veins, translucent secondary veins and no prickle-like structures. A seedling identification key was elaborated based on morphological characteristics.

Germination and seedling morphology of four South American Smilax (Smilacaceae).

Science.gov (United States)

Martins, Aline Redondo; Soares, Anielca Nascimento; Bombo, Aline Bertolosi; Fidelis, Alessandra; Novembre, Ana Dionisia da Luz Coelho; da Glória, Beatriz Appezzato

2012-03-01

Species of Smilax, also known as greenbrier, are widely distributed in Brazil and their commercial trades are carried out by the extractivism of native species. We the aim to provide information about the germination and development of seedlings in four Smilax species, different experiments were developed under controlled conditions. We evaluated two germination treatments: temperature (30 degrees C and 20-30 degrees C) and light (presence/ absence), and for few cases the tetrazolium treatment was applied. A different treatment response was observed among the studied species. Light had a significant influence in S. brasiliensis, with the highest germination rates at 20-30 degrees C in dark conditions. S. campestris showed significant differences among temperature treatments, but not to light; while S. cissoides showed high germination rates (66-78%), independently of treatment. However, S. polyantha had low germination rates (19-24%). After one year, the expanded leaves showed different characteristics among the studied species. Leaves of S. brasiliensis were ovate, coriaceous, three main veins and prickle-like structures only on the midrib on abaxial face. S. campestris leaves were oblong, coriaceous and prickle-like structures were located at the leaf midrib and margin. S. cissoides had ovate-elliptic, membranaceous leaves, with three main veins with prickle-like structures on the abaxial face. S. polyantha leaves showed ovate-elliptic, coriaceous leaves, with three main veins, translucent secondary veins and no prickle-like structures. A seedling identification key was elaborated based on morphological characteristics.

Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth

Directory of Open Access Journals (Sweden)

JUAN eMORAL

2015-06-01

Full Text Available Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt and the type of water stress (matric or osmotic on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30ºC during both periods, with a maximum around 20ºC. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche spp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

Temperature and water stress during conditioning and incubation phase affecting Orobanche crenata seed germination and radicle growth.

Science.gov (United States)

Moral, Juan; Lozano-Baena, María Dolores; Rubiales, Diego

2015-01-01

Orobanche crenata is a holoparasitic plant that is potentially devastating to crop yield of legume species. Soil temperature and humidity are known to affect seed germination, however, the extent of their influence on germination and radicle growth of those of O. crenata is largely unknown. In this work, we studied the effects of temperature, water potential (Ψt) and the type of water stress (matric or osmotic) on O. crenata seeds during conditioning and incubation periods. We found that seeds germinated between 5 and 30°C during both periods, with a maximum around 20°C. Germination increased with increasing Ψt from -1.2 to 0 MPa during conditioning and incubation periods. Likewise, seed germination increased logarithmically with length of conditioning period until 40 days. The impact of the type of water stress on seed germination was similar, although the radicle growth of seeds under osmotic stress was lower than under matric stress, what could explain the lowest infestation of Orobanche sp. in regions characterized by saline soil. The data in this study will be useful to forecast infection of host roots by O. crenata.

Germination and Inactivation of Alicyclobacillus acidoterrestris Spores Induced by Moderate Hydrostatic Pressure.

Science.gov (United States)

Sokołowska, Barbara; Skapska, Sylwia; Fonberg-Broczek, Monika; Niezgoda, Jolanta; Porebska, Izabela; Dekowska, Agnieszka; Rzoska, Sylwester J

2015-01-01

Given the importance of spoilage caused by Alicyclobacillus acidoterrestris for the fruit juice industry, the objective of this work was to study the germination and inactivation of A. acidoterrestris spores induced by moderate hydrostatic pressure. Hydrostatic pressure treatment can induce the germination and inactivation of A. acidoterrestris spores. At low pH, spore germination of up to 3.59-3.75 log and inactivation of 1.85-2.04 log was observed in a low pressure window (200-300 MPa) applied at 50 degrees C for 20 min. Neutral pH suppressed inactivation, the number of spores inactivated at pH 7.0 was only 0.24-1.06 log. The pressurization temperature significantly affected spore germination and inactivation. The degree of germination in apple juice after pressurization for 30 min with 200 MPa at 20 degrees C was 2.04 log, with only 0.61 log of spores being inactivated, while at 70 degrees C spore germination was 5.94 log and inactivation 4.72 log. This temperature strongly stimulated germination and inactivation under higher (500 MPa) than lower (200 MPa) pressure. When the oscillatory mode was used, the degree of germination and inactivation was slightly higher than at continuous mode. The degree of germination and inactivation was inversely proportional to the soluble solids content and was lowest in concentrated apple juice.

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.

[The research of Valeriana amurensis seed germination characteristics].

Science.gov (United States)

Liu, Juan; Yang, Chun-Rong; Jiang, Bo; Fang, Min; Du, Juan

2011-10-01

To study the effect of different treatments on the Valeriana amurensis seed germination rate. Used different chemical reagents and seed soakings on the routine germination test and the orthogonal test of the Valeriana amurensis seed, calculated the germination rate under different germination condition. Valeriana amurensis treated with different chemical reagends had different germination rate. The suitable immersion time could enhance Valeriana amurensis seed germination rate. Different treatment time, different disposal temperature, different germination temperature would have an impact on the Valeriana amurensis seed germination rate. In order to raise the Valeriana amurensis seed germination rate, use appropriate treatment on the seed before plant seeds; The seed growing must under suitable time and temperature.

TEMPERATURE EFFECT ON THE GERMINATION AND ROOT GROWTH OF JATOBÁ-MIRIM (Guibourtia hymenaefolia (Moric. J. Léonard SEEDS

Directory of Open Access Journals (Sweden)

Ademir Kleber Morbeck de Oliveira

2014-03-01

Full Text Available http://dx.doi.org/10.5902/1980509813328Jatobá-Mirim species belongs to Fabaceae family and is distributed through Pantanal and Caatinga areas.Its wood is suitable for the construction and the manufacture of luxury furniture and is recommendedfor urban forestry and used to compose heterogeneous reforestation. Taking into account their potentialuse this work was developed with the objective of evaluating the effect of different temperatures on thegermination rate and initial root growth of Jatobá-Mirim seeds. The seeds used in this experiment wereharvested at ‘Cabeceira do Prata’ farm, located in ‘Jardim’ municipality, in Mato Grosso do Sul state, inSeptember 2009. The material collected was transported to the Laboratory of Research on Bio-diversityand Environmental Systems at Anhanguera-Uniderp University where the research was developed. Theseeds were submitted to constant temperatures of 20, 25, 30, 35 °C and alternated temperatures of 20-30 and 25-35 °C, in six treatments, kept in germination cameras of B.O.D type. The obtained results showthat the best temperatures for the seed germination are 30 oC (90%, 35 °C (97% and 25-35 °C (90%,statistically equal, certifying that those temperatures are more efficient to promote the germination. Takinginto account the mean time for germination, germination speed index and dry matter production, constanttemperatures of 30 and 35oC are better and its results, statistically equal and higher than other treatments

Aberrant Meiotic Modulation Partially Contributes to the Lower Germination Rate of Pollen Grains in Maize (Zea mays L.) Under Low Nitrogen Supply.

Science.gov (United States)

Zheng, Hongyan; Wu, Huamao; Pan, Xiaoying; Jin, Weiwei; Li, Xuexian

2017-02-01

Pollen germination is an essential step towards successful pollination during maize reproduction. How low niutrogen (N) affects pollen germination remains an interesting biological question to be addressed. We found that only low N resulted in a significantly lower germination rate of pollen grains after 4 weeks of low N, phosphorus or potassium treatment in maize production. Importantly, cytological analysis showed 7-fold more micronuclei in male meiocytes under the low N treatment than in the control, indicating that the lower germination rate of pollen grains was partially due to numerous chromosome loss events resulting from preceding meiosis. The appearance of 10 bivalents in the control and low N cells at diakinesis suggested that chromosome pairing and recombination in meiosis I was not affected by low N. Further gene expression analysis revealed dramatic down-regulation of Nuclear Division Cycle 80 (Ndc80) and Regulator of Chromosome Condensation 1 (Rcc1-1) expression and up-regulation of Cell Division Cycle 20 (Cdc20-1) expression, although no significant difference in the expression level of kinetochore foundation proteins Centromeric Histone H3 (Cenh3) and Centromere Protein C (Cenpc) and cohesion regulators Recombination 8 (Rec8) and Shugoshin (Sgo1) was observed. Aberrant modulation of three key meiotic regulators presumably resulted in a high likelihood of erroneous chromosome segregation, as testified by pronounced lagging chromosomes at anaphase I or cell cycle disruption at meiosis II. Thus, we proposed a cytogenetic mechanism whereby low N affects male meiosis and causes a higher chromosome loss frequency and eventually a lower germination rate of pollen grains in a staple crop plant. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Seed dormancy responses to temperature relate to Nothofagus species distribution and determine temporal patterns of germination across altitudes in Patagonia.

Science.gov (United States)

Arana, María V; Gonzalez-Polo, Marina; Martinez-Meier, Alejandro; Gallo, Leonardo A; Benech-Arnold, Roberto L; Sánchez, Rodolfo A; Batlla, Diego

2016-01-01

Seeds integrate environmental cues that modulate their dormancy and germination. Although many mechanisms have been identified in laboratory experiments, their contribution to germination dynamics in existing communities and their involvement in defining species habitats remain elusive. By coupling mathematical models with ecological data we investigated the contribution of seed temperature responses to the dynamics of germination of three Nothofagus species that are sharply distributed across different altitudes in the Patagonian Andes. Seed responsiveness to temperature of the three Nothofagus species was linked to the thermal characteristics of their preferred ecological niche. In their natural distribution range, there was overlap in the timing of germination of the species, which was restricted to mid-spring. By contrast, outside their species distribution range, germination was temporally uncoupled with altitude. This phenomenon was described mathematically by the interplay between interspecific differences in seed population thermal parameters and the range in soil thermic environments across different altitudes. The observed interspecific variations in seed responsiveness to temperature and its environmental regulation, constitute a major determinant of the dynamics of Nothofagus germination across elevations. This phenomenon likely contributes to the maintenance of patterns of species abundance across altitude by placing germinated seeds in a favorable environment for plant growth. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Seed germination of Stenocereus thurberi (Cactaceae) under different solar irradiation levels

International Nuclear Information System (INIS)

Nolasco, H.; Vega-Villasante, F.; Diaz-Rondero, A.

1997-01-01

Germination of Stenocereus thurberi seeds was evaluated under different conditions of solar irradiation and humidity. Seed germination increased under higher humidity and low solar irradiation which provided cooler temperatures and higher water availability. Seedlings were also greener and more turgid under these conditions. Increased solar irradiation reduced seed germination and decreased seedling size and water content. The results of this study support the importance of natural shelter systems in the arid zones in providing better conditions for S. thurberi seeds germination and seedling establishment, particularly in the desert of Baja California. (author)

Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals

Directory of Open Access Journals (Sweden)

Pham A. Tuan

2018-05-01

Full Text Available Seed dormancy is an adaptive trait that does not allow the germination of an intact viable seed under favorable environmental conditions. Non-dormant seeds or seeds with low level of dormancy can germinate readily under optimal environmental conditions, and such a trait leads to preharvest sprouting, germination of seeds on the mother plant prior to harvest, which significantly reduces the yield and quality of cereal crops. High level of dormancy, on the other hand, may lead to non-uniform germination and seedling establishment. Therefore, intermediate dormancy is considered to be a desirable trait as it prevents the problems of sprouting and allows uniformity of postharvest germination of seeds. Induction, maintenance, and release of seed dormancy are complex physiological processes that are influenced by a wide range of endogenous and environmental factors. Plant hormones, mainly abscisic acid (ABA and gibberellin (GA, are the major endogenous factors that act antagonistically in the control of seed dormancy and germination; ABA positively regulates the induction and maintenance of dormancy, while GA enhances germination. Significant progress has been made in recent years in the elucidation of molecular mechanisms regulating ABA/GA balance and thereby dormancy and germination in cereal seeds, and this review summarizes the current state of knowledge on the topic.

Molecular Mechanisms Underlying Abscisic Acid/Gibberellin Balance in the Control of Seed Dormancy and Germination in Cereals

Science.gov (United States)

Tuan, Pham A.; Kumar, Rohit; Rehal, Pawanpuneet K.; Toora, Parneet K.; Ayele, Belay T.

2018-01-01

Seed dormancy is an adaptive trait that does not allow the germination of an intact viable seed under favorable environmental conditions. Non-dormant seeds or seeds with low level of dormancy can germinate readily under optimal environmental conditions, and such a trait leads to preharvest sprouting, germination of seeds on the mother plant prior to harvest, which significantly reduces the yield and quality of cereal crops. High level of dormancy, on the other hand, may lead to non-uniform germination and seedling establishment. Therefore, intermediate dormancy is considered to be a desirable trait as it prevents the problems of sprouting and allows uniformity of postharvest germination of seeds. Induction, maintenance, and release of seed dormancy are complex physiological processes that are influenced by a wide range of endogenous and environmental factors. Plant hormones, mainly abscisic acid (ABA) and gibberellin (GA), are the major endogenous factors that act antagonistically in the control of seed dormancy and germination; ABA positively regulates the induction and maintenance of dormancy, while GA enhances germination. Significant progress has been made in recent years in the elucidation of molecular mechanisms regulating ABA/GA balance and thereby dormancy and germination in cereal seeds, and this review summarizes the current state of knowledge on the topic. PMID:29875780

Effects of low dose gamma irradiation on the germination and physiological activity of old red pepper (Capsicum annuum L.) seed

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Sung; Back, Myung Hwa; Lee, Hae Youn; Lee, Young Keun [KAERI, Daejeon (Korea, Republic of)

2001-12-15

To observe the stimulating effects of low dose gamma radiation on the germination and physiological activity of germinating seeds of old red pepper (Capsicum annuum L. cv, Jokwang and cv. Hongkwang), seeds were irradiated at the dose of 2{approx}50 Gy. The germination rate of irradiation group was higher than that of the control. Especially it was highest at the early stage of induction. The germination rate at 7 days after sowing in Jokwang and Hongkwang cultivar was high as 74% and 11% at 4 Gy and 8 Gy irradiation group, respectively. The seedling height of Jokwang cultivar was noticeably high at 4 Gy irradiation group and that of Hongkwang cultivar at 8 Gy Irradiation group. The protein contents of seedlings from seeds irradiated with low dose gamma radiation of Jokwang cultivar increased at the late stage of induction and that of Hongkwang cultivar at the early stage of induction. Catalase and peroxidase activities of seedlings from seeds irradiated with low dose gamma radiation of Jokwang cultivar increased at 4 Gy irradiation group and that of Hongkwang cultivar at 8 Gy irradiation group.

Germination Ecology of Johnsongrass Seeds (Sorghum halepense (L. PERS.

Directory of Open Access Journals (Sweden)

Mehdi Mojab

2018-01-01

Full Text Available Introduction Johnsongrass (Sorghum halepense (L. PERS is one of the most controversial and problematic weed. It is damaging at more than 30 different crops in 53 different countries. S. halepense (L. is a perennial weed reproducing by seed and rhizome. Since it produces many seeds and rhizomes, it is difficult to control it. A weed germination plays an important role in attaining a prosper establishment in a typical agri-ecosystem; and this trend is adjusted with some environmental factors such as light, temperature, salinity, pH and soil moisture. If you consider the pattern of germination and emergence of weed species, you will able to provide comprehensive information to develop weed management strategies in the future. Thus, the purpose of current research has been to evaluate the breaking methods of the seed dormancy, effect of constant and alternative temperature, light, salinity and drought stress and burial depth on germination and seedling emergence of Johnsongrass. Materials and Methods Seeds of Johnsongrass (S. halepense L. were collected in June 2013 from plants located at the research farmlands of the Agriculture research centre of Fars province in Zarghan town, Iran. Experimental treatments of Breaking Dormancy consist of six level of scarification with 95-98% acid sulfuric (4, 8, 15, 30, 45 and 60 minutes, in the other one, there were the soaked seeds in the water for 24, 48, 72 and 96 hours, and in the next group the seeds were heated in a 95- 98 boiling water for two and five minutes, and again in the next group, for 15, 30, 45 and 60 days, the seeds were chilled in 3 C, and in the last group, the seeds stored in 3 and 12 months after harvest comparing to control treatment. A number of 25 seeds were transferred to incubators to identify a suitable temperature and light regime for subsequent experiments of germination and determine under alternative day/night temperatures (15/5, 20/10, 30/15 and 35/20 C and constant temperature

Germination and storage of caranda seeds (Copernicia alba

Directory of Open Access Journals (Sweden)

Tathiana Elisa Masetto

2012-12-01

Full Text Available Caranda is a Brazilian native palm tree, belonging to Arecaceae family and occurring, predominan,t in the Brazilian Swampland. This work studied the germination and the caranda seeds storage behavior. The germination study was carried out in the temperatures of 25ºC and 30ºC in constant white light and the alternate temperature of 20/30ºC with 10 hours of darkness for the lowest temperature and 14 hours of light for the highest temperature, using paper and paper roll as substratum. At the end of test, the germination percentage, germination speed index, germination medium time and the primary root length were evaluated. After the seeds improvement, it was obtained two sub-samples destined for 30 days storage in two invironments: cold and dry chamber (16ºC/55% UR and freezer (-18ºC. The following tests, water content, germination, germination medium time and primary root length were evaluated. The caranda seeds germination in paper roll and on paper is favored by the temperature of 20/30ºC in paper roll and on paper and paper roll on 30ºC. The freezing and cold camera storage during 30 days are efficient to reduce the germination medium time of caranda seeds and to keep the germination percentage.

Estimation of base temperatures for nine weed species.

Science.gov (United States)

Steinmaus, S J; Prather, T S; Holt, J S

2000-02-01

Experiments were conducted to test several methods for estimating low temperature thresholds for seed germination. Temperature responses of nine weeds common in annual agroecosystems were assessed in temperature gradient experiments. Species included summer annuals (Amaranthus albus, A. palmeri, Digitaria sanguinalis, Echinochloa crus-galli, Portulaca oleracea, and Setaria glauca), winter annuals (Hirschfeldia incana and Sonchus oleraceus), and Conyza canadensis, which is classified as a summer or winter annual. The temperature below which development ceases (Tbase) was estimated as the x-intercept of four conventional germination rate indices regressed on temperature, by repeated probit analysis, and by a mathematical approach. An overall Tbase estimate for each species was the average across indices weighted by the reciprocal of the variance associated with the estimate. Germination rates increased linearly with temperature between 15 degrees C and 30 degrees C for all species. Consistent estimates of Tbase were obtained for most species using several indices. The most statistically robust and biologically relevant method was the reciprocal time to median germination, which can also be used to estimate other biologically meaningful parameters. The mean Tbase for summer annuals (13.8 degrees C) was higher than that for winter annuals (8.3 degrees C). The two germination response characteristics, Tbase and slope (rate), influence a species' germination behaviour in the field since the germination inhibiting effects of a high Tbase may be offset by the germination promoting effects of a rapid germination response to temperature. Estimates of Tbase may be incorporated into predictive thermal time models to assist weed control practitioners in making management decisions.

Control of Seed Germination and Plant Development by Carbon and Nitrogen Availability

Directory of Open Access Journals (Sweden)

Daniel eOsuna

2015-11-01

Full Text Available Little is known about the molecular basis of the influence of external carbon/nitrogen (C/N ratio and other abiotic factors on phytohormones regulation during seed germination and plant developmental processes, and the identification of elements that participate in this response is essential to understand plant nutrient perception and signaling. Sugars (sucrose, glucose and nitrate not only act as nutrients but also as signaling molecules in plant development. A connection between changes in auxin transport and nitrate signal transduction has been reported in Arabidopsis thaliana through the NRT1.1, a nitrate sensor and transporter that also functions as a repressor of lateral root growth under low concentrations of nitrate by promoting auxin transport. Nitrate inhibits the elongation of lateral roots, but this effect is significantly reduced in abscisic acid (ABA-insensitive mutants, what suggests that ABA might mediate the inhibition of lateral root elongation by nitrate. Gibberellin (GA biosynthesis has been also related to nitrate level in seed germination and its requirement is determined by embryonic ABA. These mechanisms connect nutrients and hormones signaling during seed germination and plant development. Thus, the genetic identification of the molecular components involved in nutrients-dependent pathways would help to elucidate the potential crosstalk between nutrients, nitric oxide (NO and phytohormones (ABA, auxins and GAs in seed germination and plant development. In this review we focus on changes in C and N levels and how they control seed germination and plant developmental processes through the interaction with other plant growth regulators, such as phytohormones.

Development of a Threshold Model to Predict Germination of Populus tomentosa Seeds after Harvest and Storage under Ambient Condition

Science.gov (United States)

Wang, Wei-Qing; Cheng, Hong-Yan; Song, Song-Quan

2013-01-01

Effects of temperature, storage time and their combination on germination of aspen (Populus tomentosa) seeds were investigated. Aspen seeds were germinated at 5 to 30°C at 5°C intervals after storage for a period of time under 28°C and 75% relative humidity. The effect of temperature on aspen seed germination could not be effectively described by the thermal time (TT) model, which underestimated the germination rate at 5°C and poorly predicted the time courses of germination at 10, 20, 25 and 30°C. A modified TT model (MTT) which assumed a two-phased linear relationship between germination rate and temperature was more accurate in predicting the germination rate and percentage and had a higher likelihood of being correct than the TT model. The maximum lifetime threshold (MLT) model accurately described the effect of storage time on seed germination across all the germination temperatures. An aging thermal time (ATT) model combining both the TT and MLT models was developed to describe the effect of both temperature and storage time on seed germination. When the ATT model was applied to germination data across all the temperatures and storage times, it produced a relatively poor fit. Adjusting the ATT model to separately fit germination data at low and high temperatures in the suboptimal range increased the models accuracy for predicting seed germination. Both the MLT and ATT models indicate that germination of aspen seeds have distinct physiological responses to temperature within a suboptimal range. PMID:23658654

The effects of temperature on the dormancy and germination of Cirsium arvense (L. Scop. seeds

Directory of Open Access Journals (Sweden)

Anna Bochenek

2011-01-01

Full Text Available The ecophysiological regulation of seed dormancy in perennial species and those with a varied life cycle has not been studied in detail yet. That is why an attempt has been made to determine the Cirsium arvense seed water relations during stratification and afterripening at different temperatures and germination at constant or fluctuating temperatures on the basis of the hydrotime model. The obtained results showed that breaking of the primary dormancy of achenes took place only during the first stratification month at moderate temperatures, mainly due to an increase in the average water-stress tolerance in a seed population. The induction of secondary seed dormancy during after-ripening at all temperatures resulted mostly from a substantial loss of the seeds' ability to tolerate water stress. Fluctuating temperatures affected neither seed germination nor the hydrotime model parameters. The analysis of the variations of hydrotime model parameters allows a better understanding of the physiological basis of seed dormancy relief and induction.

Dormancy overcoming, temperatures and substrates on germination of Mimosa tenuiflora Willd seeds

Directory of Open Access Journals (Sweden)

Clarisse Pereira Benedito

2017-03-01

Full Text Available Mimosa tenuiflora Willd., popularly known as jurema-preta, is an arboreal species of great importance for the brazilian Northeast due to its uses as a medicinal plant and in the restoration of degraded soils. No information is available in the Rules for Seed Analysis and the Instructions for Seed Analysis of Forest Species regarding ideal conditions for of this species. Thus, this study aimed at evaluating the influence of pre-germination treatments, in addition to verifying the germination performance at different temperatures and in different substrates. In both experiments, four replicates of 25 seeds were used for each treatment. In experiment I, seeds were submitted to the following methods for overcoming dormancy: witness - Intact seeds (T1 immersion in water at 100 °C for 1 (T2, 2 (T3, 3 (T4, 4 (T5, 5 (T6 and 6 min (T7, immersion in concentrated sulfuric acid for 1 (T8, 4 (T9, 7 (T10, 10 (T11 and 13 min (T12, scarification on sandpaper n° 80 (T13 and lopping in the region opposite the micropyle (T14. In experiment II, seed germination was evaluated in four types of substrates: between sand, paper on, paper roll and between vermiculite and at six different temperatures: 20, 25, 30, 35, 40 °C and alternating between 20 and 30 °C. Immersion in hot water for 1, 2, 3, 4, 5 and 6 min, sulfuric acid treatment for 10 and 13 min, sand paper and lopping were the most appropriate treatments to overcome seed dormancy. The seed germination of M. Tenuiflora should be carried out at 25 °C on paper roll substrate.

The Effect of Seasonal Ambient Temperatures on Fire-Stimulated Germination of Species with Physiological Dormancy: A Case Study Using Boronia (Rutaceae)

Science.gov (United States)

Auld, Tony D.; Keith, David A.; Hui, Francis K. C.; Ooi, Mark K. J.

2016-01-01

Dormancy and germination requirements determine the timing and magnitude of seedling emergence, with important consequences for seedling survival and growth. Physiological dormancy is the most widespread form of dormancy in flowering plants, yet the seed ecology of species with this dormancy type is poorly understood in fire-prone vegetation. The role of seasonal temperatures as germination cues in these habitats is often overlooked due to a focus on direct fire cues such as heat shock and smoke, and little is known about the combined effects of multiple fire-related cues and environmental cues as these are seldom assessed in combination. We aimed to improve understanding of the germination requirements of species with physiological dormancy in fire-prone floras by investigating germination responses across members of the Rutaceae from south eastern Australia. We used a fully factorial experimental design to quantify the individual and combined effects of heat shock, smoke and seasonal ambient temperatures on germination of freshly dispersed seeds of seven species of Boronia, a large and difficult-to-germinate genus. Germination syndromes were highly variable but correlated with broad patterns in seed morphology and phylogenetic relationships between species. Seasonal temperatures influenced the rate and/or magnitude of germination responses in six species, and interacted with fire cues in complex ways. The combined effects of heat shock and smoke ranged from neutral to additive, synergistic, unitive or negative and varied with species, seasonal temperatures and duration of incubation. These responses could not be reliably predicted from the effect of the application of single cues. Based on these findings, fire season and fire intensity are predicted to affect both the magnitude and timing of seedling emergence in wild populations of species with physiological dormancy, with important implications for current fire management practices and for population

The biological role of exogenic factors in broomrape germination

International Nuclear Information System (INIS)

Zhelev, N.

1987-01-01

The often observed contradictory effect of the substances stimulating broomrape seed germination were assessed and explained. Low and optimal concentrations of these substances had a stimulating effect, while the high concentrations produced an inhibiting effect. For chemically pure mustard oil, phenylisothiocianate and allylisothiocianate such concentrations are 10 -4 to 10 -3 and more. The effectiveness of substances stimulating germination is conditioned in many cases by their watersoluble or gaseous state. The latter state of the stimulating substances is more natural, more economic and more efficient for the fumigation (in low concentrations) of the soil layer penetrated by the roots where parasitic seeds are present. A considerable number of agricultural crops, releasing by their roots essential oils containing glucosides, the hydrolysis of which results in elimination of volatile products of mustard oil type, represent natural stimulators for the germination of broomrape seeds. The effect of gamma-ray irradiation of parasitic seeds depends on their state. Dry seeds endure 80-120 krad, while moist ones - only 40-80 krad. Broomrape (O. ramosa and O. mutella) seeds begin their germination at 10 grad C. The optimal temperature for germination is 18-30 grad C, while 35-40 grad C irreversively discontinues the germination

BIOSECURITY FOR REDUCING OCHRATOXIN A PRODUCTIVITY AND THEIR IMPACT ON GERMINATION AND ULTRASTRUCTURES OF GERMINATED WHEAT GRAINS

Directory of Open Access Journals (Sweden)

M.M.

2012-08-01

Full Text Available Ochratoxin A (OTA is a secondary metabolite of some fungi that causes very serious problems for plants, animals and humans. Various microorganisms such as bacteria and microscopic fungi have been tested for their abilities to prevent ochratoxin A contamination or detoxify foods. In this study, Saccharomyces cerevisiae and Lactobacillus bulgaricus reduced OTA production by Aspergillus ochraceus to 40.88 µg/ml ( productivity 60.69% and 13.80 µg/ml (productivity 20.48% respectively compared with the control (67.35 µg/ml (productivity 100%. The results clearly indicated that the seed germinibility in the presence of OTA was decreased with increasing concentration, whereas the germinibility was uncompletely ceased at high concentration (67.35 µg/ml of OTA. The maximum amount of germination was observed in control (without OTA treatment and at low concentration (13.80 µg/ml within 4 days. Antioxidant enzymes catalase and peroxidase decreased in germinated grains treated with OTA. Catalase was 18.12 U/ml in grains treated with low concentration (13.80 µg/ml of OTA while at high concentration (67.35 µg/ml, it was 12.23 U/ml compared with the control (20.33 U/ml. On the other hand, peroxidase decreased only in germinated grains treated with high concentration of OTA. The ultrastructural studies indicate that there were dramatic differences between the cells of root system of wheat seedlings of grains treated and untreated with the OTA. Cell ultrastructures of treated grains with OTA showed that the cytoplasmic membrane collapses away from the cell wall. Plasmodesmata threads were appeared in untreated cells but not formed in treated cells.

Effects of origin, seasons and storage under different temperatures on germination of Senecio vulgaris (Asteraceae seeds

Directory of Open Access Journals (Sweden)

Noel Ndihokubwayo

2016-08-01

Full Text Available Invasive plants colonize new environments, become pests and cause biodiversity loss, economic loss and health damage. Senecio vulgaris L. (Common groundsel, Asteraceae, a widely distributing cosmopolitan weed in the temperate area, is reported with large populations in the north–eastern and south–western part, but not in southern, central, or north-western parts of China. We studied the germination behavior of S. vulgaris to explain the distribution and the biological invasion of this species in China. We used seeds originating from six native and six invasive populations to conduct germination experiments in a climate chamber and under outdoor condition. When incubated in a climate chamber (15 °C, seeds from the majority of the populations showed >90% germination percentage (GP and the GP was equal for seeds with a native and invasive origin. The mean germination time (MGT was significantly different among the populations. Under outdoor conditions, significant effects of origin, storage conditions (stored at 4 °C or ambient room temperature, ca. 27 °C and seasons (in summer or autumn were observed on the GP while the MGT was only affected by the season. In autumn, the GP (38.6% was higher and the MGT was slightly longer than that in summer. In autumn, seeds stored at 4 °C showed higher GP than those stored at ambient room temperature (ca.27 °C, and seeds from invasive populations revealed higher GP than those from native populations. The results implied that the high temperature in summer has a negative impact on the germination and might cause viability loss or secondary dormancy to S. vulgaris seeds. Our study offers a clue to exploring what factor limits the distribution of S. vulgaris in China by explaining why, in the cities in South-East China and central China such as Wuhan, S. vulgaris cannot establish natural and viable populations.

Effects of origin, seasons and storage under different temperatures on germination of Senecio vulgaris (Asteraceae) seeds.

Science.gov (United States)

Ndihokubwayo, Noel; Nguyen, Viet-Thang; Cheng, Dandan

2016-01-01

Invasive plants colonize new environments, become pests and cause biodiversity loss, economic loss and health damage. Senecio vulgaris L. (Common groundsel, Asteraceae), a widely distributing cosmopolitan weed in the temperate area, is reported with large populations in the north-eastern and south-western part, but not in southern, central, or north-western parts of China. We studied the germination behavior of S. vulgaris to explain the distribution and the biological invasion of this species in China. We used seeds originating from six native and six invasive populations to conduct germination experiments in a climate chamber and under outdoor condition. When incubated in a climate chamber (15 °C), seeds from the majority of the populations showed >90% germination percentage (GP) and the GP was equal for seeds with a native and invasive origin. The mean germination time (MGT) was significantly different among the populations. Under outdoor conditions, significant effects of origin, storage conditions (stored at 4 °C or ambient room temperature, ca. 27 °C) and seasons (in summer or autumn) were observed on the GP while the MGT was only affected by the season. In autumn, the GP (38.6%) was higher and the MGT was slightly longer than that in summer. In autumn, seeds stored at 4 °C showed higher GP than those stored at ambient room temperature (ca.27 °C), and seeds from invasive populations revealed higher GP than those from native populations. The results implied that the high temperature in summer has a negative impact on the germination and might cause viability loss or secondary dormancy to S. vulgaris seeds. Our study offers a clue to exploring what factor limits the distribution of S. vulgaris in China by explaining why, in the cities in South-East China and central China such as Wuhan, S. vulgaris cannot establish natural and viable populations.

A system to control low pressure turbine temperatures

International Nuclear Information System (INIS)

1980-01-01

An improved system to control low pressure turbine cycle steam and metal temperatures by governing the heat transfer operation in a moisture separator-reheater is described. The use of the present invention in a pressurized water reactor or a boiling water reactor steam turbine system is demonstrated. (UK)

TEMPERATURE STRESS AND THERMO DORMANCY OF VEGETABLE SEEDS OF UMBELLIFERAE CROPS. FEATURES OF INDUCTION; MANIR FESTATION AND OVERCOME

Directory of Open Access Journals (Sweden)

A. F. Buharov

2013-01-01

Full Text Available  The high6temperature stress  during 5620 days has a negative impact on activity of growth of embryo and inhibits the seeds germination of the Umbelliferae crops. The germination of the studied seeds  of different species at low temperature contributes to the recovery of the embryo growth; however; growth is less intensive in comparison  with the control. All studied Umbelliferae crops showed the differences in seed germination and development of embryos at various temperatures and duration of heat treatment.

Factors Defining Field Germination of Oilseed Radish Seeds

Directory of Open Access Journals (Sweden)

N.V. Dorofeev

2013-08-01

Full Text Available Influence of temperature, depth of crops and granulometric of soil structure on germination speed, laboratory and field germination of oilseed radish seeds were studied. It was established that the period of seed-germination is defined both by temperature and granulometric structure of soil. The highest field germination was marked on sandy loam at depth of crops' seeds at 3 cm and 20°С.

Relationship of low phytate trait with seed germination and carbohydrates content in soybean mutant Gm-lpa-TW-1

International Nuclear Information System (INIS)

Yuan Fengjie; Dong Dekun; Li Baiquan; Fu Xujun; Zhu Danhua; Zhu Shenlong

2011-01-01

The relationship between the low phytate mutation with seed germination and carbohydrate content homozygous F 5 lines with/without lpa gene derived from mutant and different wild type parents were analyzed. The results showed that LPA (low phytic acid)/HPA (high phytic acid) lines developed in autumn had higher seed germination rate than that developed in spring. LPA lines had lower seed germination rate than HPA lines when they all developed in spring. However, in all crosses LPA lines with higher seed germination rate than mutant parent Gm-lpa-TW-1 was observed. No significant difference was detected between LPA and HPA lines when they developed in autumn. Homozygous LPA lines derived from vegetable soybean had lower seed germination than those from non-vegetable varieties. There was no significant difference in total carbohydrate content between LPA and HPA homozygous lines, but the sugar content of LPA homozygous lines was significant higher than HPA lines. On the contrary, oligosaccharides content with LPA lines were significant lower than those with HPA homozygous lines in all planting environment. It is concluded that seeds field germination rate were affected by low phytate mutation gene and planting environment, and lower seed germination rate phenotype of LPA lines could be improved by genetic method. Mutant Gm-lpa-TW-1 of LPA phenotype was genetic linkage with high sugar and low oligosaccharides phenotype, so it should be benefit to breed new soybean varieties with better quality. (authors)

Germination and growth of purple passion fruit seedlings under pre-germination treatments and mycorrhizal inoculation

Directory of Open Access Journals (Sweden)

Joaquín Guillermo Ramírez Gil

2015-09-01

Full Text Available The cultivation of purple passion fruit plants has increased in Colombia, as a direct result of its well-accepted consumption. Therefore, there is a need for technological solutions aimed at the sustainable growth of its fruit, such as improving seed germination and decreasing phosphorus (P deficiencies, given its low availability in tropical soils. This study aimed to evaluate pre-germination treatments (control, apical and basal seed cuts, alternation of temperature, photoperiod, application of gibberellic acid and immersion in 96 % of H2SO4 and mycorrhizal dependency of purple passion fruit plants, using three levels of P in the soil solution (0.002 mg L-1, 0.02 mg L-1 and 0.2 mg L-1, in 35 combinations with or without the inoculation of the Glomus fasciculatum mycorrhizal fungus. A completely randomized design with five replications per treatment was used. The treatment with the most significant effect for reducing the dormancy of the purple passion fruit seeds is the immersion in 96 % of H2SO4 for 20 minutes. This species shows a high mycorrhizal dependency, when coupled with 0.02 mg L-1 of P in the soil solution.

Habitat specialization through germination cueing: a comparative study of herbs from forests and open habitats.

Science.gov (United States)

Ten Brink, Dirk-Jan; Hendriksma, Harmen Pieter; Bruun, Hans Henrik

2013-02-01

This study examined the adaptive association between seed germination ecology and specialization to either forest or open habitats across a range of evolutionary lineages of seed plants, in order to test the hypotheses that (1) species' specialization to open vs. shaded habitats is consistently accompanied by specialization in their regeneration niche; and (2) species are thereby adapted to utilize different windows of opportunity in time (season) and space (habitat). Seed germination response to temperature, light and stratification was tested for 17 congeneric pairs, each consisting of one forest species and one open-habitat species. A factorial design was used with temperature levels and diurnal temperature variation (10 °C constant, 15-5 °C fluctuating, 20 °C constant, 25-15 °C fluctuating), and two light levels (light and darkness) and a cold stratification treatment. The congeneric species pair design took phylogenetic dependence into account. Species from open habitats germinated better at high temperatures, whereas forest species performed equally well at low and high temperatures. Forest species tended to germinate only after a period of cold stratification that could break dormancy, while species from open habitats generally germinated without cold stratification. The empirically derived germination strategies correspond quite well with establishment opportunities for forest and open-habitat plant species in nature. Annual changes in temperature and light regime in temperate forest delimit windows of opportunity for germination and establishment. Germination strategies of forest plants are adaptations to utilize such narrow windows in time. Conversely, lack of fit between germination ecology and environment may explain why species of open habitats generally fail to establish in forests. Germination strategy should be considered an important mechanism for habitat specialization in temperate herbs to forest habitats. The findings strongly suggest that

Dormancy and germination in short-lived lepidium perfoliatu l. (brassicaceae) seeds

International Nuclear Information System (INIS)

Tang, An-Jun; Tian, M.; Long, Chun-Lin

2010-01-01

To understand germination timing in an ecological context, the response to environmental events that effect seed dormancy is central and has to be combined with knowledge of germination responses to different ecological factors. In this study, seed dormancy, germination and seedling survival of annual short-lived clasping pepper weed Lepidium perfoliatum L. (Brassicaceae) were investigated. Three types of pre-treatments viz., various temperature dry storage, light and water stress were tested as possible dormancy and survival-affecting environmental events. Fresh mature seeds were greatly dormant. Warm (30 deg. C) dry storage more facilitated breaking dormancy, they germinated well under apt conditions (e.g. 20 deg. C and 10/20 deg. C plus periodic light, 14 h/d). For those seeds which underwent after-ripening, they could germinate at a range of constant temperatures (4, 10, 15, 20, 25, and 30 deg. C) and one alternating temperature (10/20 deg. C). Under alternating temperature regimes, the final percent germination of L. perfoliatum seeds increased from 37 deg. C to 93% when temperature altered from 4/10 deg. C to 10/20 deg. C in light, then decreased with increasing temperature. The germination pattern under constant temperature conditions was similar to that under alternating temperature and significant differences in final percent germinations and rates of germination were observed among different temperatures. Under different light treatments, final germination of showed significant differences, only with 35% of germination percentage in dark, much lower than those in red and white light (i.e. 93% and 91%, respectively). GA3 could promote the germination of non-dormant seeds in dark. When water potentials were reduced, final percent germination decreased dramatically, and few seeds germinated at -0.98 MPa (generated by PEG-8000). The changes of proline content in resultant seedlings were reverse to that of final percent germination with changing water

DOG1-imposed dormancy mediates germination responses to temperature cues

NARCIS (Netherlands)

Murphey, M.; Kovach, K.; Elnacash, T.; He, H.; Bentsink, L.; Donohue, K.

2015-01-01

Seed dormancy and environment-dependent germination requirements interact to determine the timing of germination in natural environments. This study tested the contribution of the dormancy gene Delay Of Germination 1 (DOG1) to primary and secondary dormancy induction in response to environmental

Reduced spore germination explains sensitivity of reef-building algae to climate change stressors.

Directory of Open Access Journals (Sweden)

Alexandra Ordoñez

Full Text Available Reduced seawater pH and changes in carbonate chemistry associated with ocean acidification (OA decrease the recruitment of crustose coralline algae (CCAcf., an important coral-reef builder. However, it is unclear whether the observed decline in recruitment is driven by impairment of spore germination, or post-settlement processes (e.g. space competition. To address this, we conducted an experiment using a dominant CCA, Porolithon cf. onkodes to test the independent and combined effects of OA, warming, and irradiance on its germination success and early development. Elevated CO2 negatively affected several processes of spore germination, including formation of the germination disc, initial growth, and germling survival. The magnitude of these effects varied depending on the levels of temperature and irradiance. For example, the combination of high CO2 and high temperature reduced formation of the germination disc, but this effect was independent of irradiance levels, while spore abnormalities increased under high CO2 and high temperature particularly in combination with low irradiance intensity. This study demonstrates that spore germination of CCA is impacted by the independent and interactive effects of OA, increasing seawater temperature and irradiance intensity. For the first time, this provides a mechanism for how the sensitivity of critical early life history processes to global change may drive declines of adult populations of key marine calcifiers.

NITRIC OXIDE IMPLICATION IN THE CONTROL OF SEED DORMANCY AND GERMINATION

Directory of Open Access Journals (Sweden)

Erwann eArc

2013-09-01

Full Text Available Germination ability is regulated by a combination of environmental and endogenous signals with both synergistic and antagonistic effects. Nitric oxide (NO is a potent dormancy-releasing agent in many species, including Arabidopsis, and has been suggested to behave as an endogenous regulator of this physiological blockage. Distinct reports have also highlighted a positive impact of NO on seed germination under sub-optimal conditions. However, its molecular mode of action in the context of seed biology remains poorly documented. This review aims to focus on the implications of this radical in the control of seed dormancy and germination. The consequences of NO chemistry on the investigations on both its signaling and its targets in seeds are discussed. NO-dependant protein post-translational modifications are proposed as a key mechanism underlying NO signalling during early seed germination.

A gene encoding an abscisic acid biosynthetic enzyme (LsNCED4) collocates with the high temperature germination locus Htg6.1 in lettuce (Lactuca sp.).

Science.gov (United States)

Argyris, Jason; Truco, María José; Ochoa, Oswaldo; McHale, Leah; Dahal, Peetambar; Van Deynze, Allen; Michelmore, Richard W; Bradford, Kent J

2011-01-01

Thermoinhibition, or failure of seeds to germinate when imbibed at warm temperatures, can be a significant problem in lettuce (Lactuca sativa L.) production. The reliability of stand establishment would be improved by increasing the ability of lettuce seeds to germinate at high temperatures. Genes encoding germination- or dormancy-related proteins were mapped in a recombinant inbred line population derived from a cross between L. sativa cv. Salinas and L. serriola accession UC96US23. This revealed several candidate genes that are located in the genomic regions containing quantitative trait loci (QTLs) associated with temperature and light requirements for germination. In particular, LsNCED4, a temperature-regulated gene in the biosynthetic pathway for abscisic acid (ABA), a germination inhibitor, mapped to the center of a previously detected QTL for high temperature germination (Htg6.1) from UC96US23. Three sets of sister BC(3)S(2) near-isogenic lines (NILs) that were homozygous for the UC96US23 allele of LsNCED4 at Htg6.1 were developed by backcrossing to cv. Salinas and marker-assisted selection followed by selfing. The maximum temperature for germination of NIL seed lots with the UC96US23 allele at LsNCED4 was increased by 2-3°C when compared with sister NIL seed lots lacking the introgression. In addition, the expression of LsNCED4 was two- to threefold lower in the former NIL lines as compared to expression in the latter. Together, these data strongly implicate LsNCED4 as the candidate gene responsible for the Htg6.1 phenotype and indicate that decreased ABA biosynthesis at high imbibition temperatures is a major factor responsible for the increased germination thermotolerance of UC96US23 seeds.

The Effects of Storage on Germination Characteristics and Enzyme Activity of Sorghum Seeds

Directory of Open Access Journals (Sweden)

Azadi M.S.

2013-11-01

Full Text Available Seed moisture content (MC and storage temperature are the most important factors affecting seed longevity and vigor. Exposure to warm, moist air is principally responsible for this. Proper storage and optimum seed moisture content can affect the grain quality significantly. The purpose of this study was to evaluate the different storage treatments on seed quality of sorghum. The seed materials were fresh without any storage period. For storage treatments, 3 seed moisture contents (6, 10, 14 % were stored for 8 month in 0.5 L capacity sealed aluminum foil packet in 0.3 bar inside incubators set at 4 temperatures (5, 15, 25, 35 °C. After storage time, the higher the storage temperature, the lower was the grain quality of sorghum. The highest germination percentage, germination index, normal seedling percentage were achieved in control conditions (0 day of storage. Our results showed that increasing storage duration resulted higher reduction in germination characteristics. Also our results showed that, germination percentage, means time to germination, germination index, normal seedling percentage decrease significantly by storage. Enzyme activity decrease significantly by increased in storage.

Effect of microwave irradiation on germination and seedling growth physiological characteristics of alfalfa seeds after storage

International Nuclear Information System (INIS)

Chen Liyu; Zhang Shuqing; Li Jianfeng; Shi Shangli; Huo Pinghui

2012-01-01

In order to study the effect of microwave irradiation on germination and growth physiological characteristics of seeds that stored for years, the irradiated alfalfa seeds that stored at room temperature for 2 years were used to conduct the germination and pot culture tests, and the germination rate, radical elongation, growth height, individual nodule, nitrogenase activity, chlorophyll content and chlorophyll fluorescence parameters were measured. On the 15th day of germination, the germination rates of all the treatments are higher than that of the control, which decrease with the elongation of time. On the llst day of germination, the radical length of all the treatments is lower than that of the control. Growth height, individual nodule, fresh weight and dry weight for the 40 s irradiation treatment are higher than that of the control. Nitrogenase activity of all the treatments is lower than that of the control (P < O.05). The chlorophyll content reaches its maximum when being irradiated for 10 s, and the variation for F 0 and F v /F m of all treatments indicates that the light conversion efficiency of the leaves derived from the irradiated alfalfa seeds that stored for 2 a at room temperature is still relatively stressed. (authors)

IMPORTANCE OF STORAGE CONDITIONS AND SEED TREATMENT FOR SUNFLOWER HYBRIDS SEEDS GERMINATION

Directory of Open Access Journals (Sweden)

Goran Krizmanić

2014-12-01

Full Text Available In this research we have determined germination energy and germination of seeds of sunflower hybrids ‘Luka’ and ‘Apolon’, at the beginning of storage and 6, 12 and 18 months after of storage period (2011-2012 in the floor concrete storage at two different air temperatures and humidity (S-1: air temperature 15-18°C and relative air humidity 65-70% as well as in climate chamber (S-2: air temperature 10-12°C and relative air humidity 60-65%, stored in four treatments (Control: processed-untreated seed; T-1: treated with A.I. metalaxyl-M; T-2: treated with A.I. metalaxyl-M + A.I. imidacloprid and T-3: treated with A.I. metalaxyl-M + A.I. clothianidin. Based on the obtained results we have determined that sunflower hybrid ‘Luka’, compared to hybrid ‘Apolon’, in the given storage conditions and with the same seed treatment has 5-8% higher germination energy and seed germination and that in climate chamber both hybrids have 5-7% higher germination energy. Seed treatment of both sunflower hybrids with A.I. imidacloprid maximally reduced initial germination energy and seed germination in all tested periods and conditions of storage. On the average, natural seed, after 18 months of storage did not have better seed quality compared to seed treated with A.I. metalaxyl-M while other treatments had more significant influence on reduction of germination energy and seed germination, 6-15%. On the average, compared to other variants, seeds treated with A.I. metalaxyl-M after 18 months of storage in both storage conditions had higher germination energy by 4-15%, and seed germination by 2-12%.

The effect of low temperature plasma on DNA damage of maize seeds

International Nuclear Information System (INIS)

Uhrin, F.; Ondriasova, K.; Kyzek, S.; Galova, E.; Medvecka, V.; Zahoranova, A.

2017-01-01

It is known that the low temperature plasma shows antimicrobial and disinfecting effects. It also supports the seed germination and it is used in many fields of common life. But there is just a few scientific papers dealing with the genotoxic properties of plasma. In our work, we try to determine the relative rate of DNA double strand breaks formation resulting from the low temperature plasma treatment in the seeds of Zea mays L. using the constant field gel electrophoresis (CFGE). We compared DNA damage in seedlings resulting from plasma and zeocin treatment with seedlings, which seeds were treated just with zeocin. (authors)

Storage on maternal plants affects light and temperature on requirements during germination in two small seeded halophytes in the arabian deserts

International Nuclear Information System (INIS)

Ali, A.; Gairola, S.

2015-01-01

Seeds are either stored in a soil seed bank or retained on maternal plants until they are released (aerial seed bank). Though there are extensive studies on the germination requirements of seeds in soil banks of saline habitats, studies conducted for halophytes with aerial seed banks are rare. We assessed the impact of aerial and room-temperature storages on the light and temperature requirements during germination in two small-seeded halophytes: Halocnmum strobilaceum having a short-term aerial seed bank (less than one year) and Halopeplis perfoliata having a longer term aerial seed bank (up to two years). Seed storage in the aerial bank reduced the germination in H. strobilaceum, but either increased it (5-months storage) or had no effect (17-months storage) in H. perfoliata. Seeds of both species that were stored in aerial bank germinated to higher percentages in light than in darkness, indicating that considerable portions of the seed populations are light sensitive. Seeds of H. perfoliata attained less than 5.0 percentage germination in darkness at higher temperatures, compared to more than 90.0 percentage in light. The results support the hypothesis that the aerial seed bank is an adaptive strategy for survival in the saline habitats of the two species. (author)

Ecophysiology of seed germination in Digitaria insularis ((L.) Fedde)

OpenAIRE

Mendonça,Giovana Soares de; Martins,Cibele Chalita; Martins,Dagoberto; Costa,Neumárcio Vilanova da

2014-01-01

The invasive behaviour of sourgrass (Digitaria insularis) in cultivated areas is due to its strategy of aggressive regeneration, which is based on seed germination. Knowledge of the physiological ecology of this species can contribute to the development of management and control strategies. The aim of this research was to understand the effects of provenance, temperature and light on the germination of sourgrass seeds collected in the Brazilian state of São Paulo in the cities of Americana, B...

Low-dose ionizing radiation limitations to seed germination: Results from a model linking physiological characteristics and developmental-dynamics simulation strategy.

Science.gov (United States)

Liu, Hui; Hu, Dawei; Dong, Chen; Fu, Yuming; Liu, Guanghui; Qin, Youcai; Sun, Yi; Liu, Dianlei; Li, Lei; Liu, Hong

2017-08-01

There is much uncertainty about the risks of seed germination after repeated or protracted environmental low-dose ionizing radiation exposure. The purpose of this study is to explore the influence mechanism of low-dose ionizing radiation on wheat seed germination using a model linking physiological characteristics and developmental-dynamics simulation. A low-dose ionizing radiation environment simulator was built to investigate wheat (Triticum aestivum L.) seeds germination process and then a kinetic model expressing the relationship between wheat seed germination dynamics and low-dose ionizing radiation intensity variations was developed by experimental data, plant physiology, relevant hypotheses and system dynamics, and sufficiently validated and accredited by computer simulation. Germination percentages were showing no differences in response to different dose rates. However, root and shoot lengths were reduced significantly. Plasma governing equations were set up and the finite element analysis demonstrated H 2 O, CO 2 , O 2 as well as the seed physiological responses to the low-dose ionizing radiation. The kinetic model was highly valid, and simultaneously the related influence mechanism of low-dose ionizing radiation on wheat seed germination proposed in the modeling process was also adequately verified. Collectively these data demonstrate that low-dose ionizing radiation has an important effect on absorbing water, consuming O 2 and releasing CO 2 , which means the risk for embryo and endosperm development was higher. Copyright © 2017 Elsevier Ltd. All rights reserved.

Germination traits of three weed species in Kosovo

Directory of Open Access Journals (Sweden)

A. Mehmeti

2010-02-01

Full Text Available Amaranthus retroflexus, Echinochloa crus-galli and Datura stramonium are the most important weed species in Kosovo. They cause severe yield depression, contaminate fodder and negatively affect growth and reproduction of other weed species. To counteract these problems, specific strategies need to be developed. Such strategies should consider information on species germination traits. In this context, our study provides information on temperature requirements for germination. Seeds of A. retroflexus, E. crus-galli and D. stramonium were harvested in two sub-regions of Kosovo (western and eastern parts differing in climate and land use. They were set for germination experiments in growth chambers at temperatures ranging from 3 to 35 °C and under field conditions. In both experiments, the germination rate differed between species and provenances. In the growth chamber experiment, germination of all three species was negligible below 15 °C and reached the highest rates between 24 and 30 °C. Seeds originating from the western part of Kosovo had higher germination rates and required a lower temperature for germination than seeds originating from the eastern part. In the field experiment, the time-dependent germination behaviour of D. stramonium differed between provenances. In general, germination started when soil temperature was above 18 °C and continued as long as the soil was moist. The results are discussed in the context of the need to develop weed management strategies against these weeds in Kosovo.

DNA damage checkpoint kinase ATM regulates germination and maintains genome stability in seeds.

Science.gov (United States)

Waterworth, Wanda M; Footitt, Steven; Bray, Clifford M; Finch-Savage, William E; West, Christopher E

2016-08-23

Genome integrity is crucial for cellular survival and the faithful transmission of genetic information. The eukaryotic cellular response to DNA damage is orchestrated by the DNA damage checkpoint kinases ATAXIA TELANGIECTASIA MUTATED (ATM) and ATM AND RAD3-RELATED (ATR). Here we identify important physiological roles for these sensor kinases in control of seed germination. We demonstrate that double-strand breaks (DSBs) are rate-limiting for germination. We identify that desiccation tolerant seeds exhibit a striking transcriptional DSB damage response during germination, indicative of high levels of genotoxic stress, which is induced following maturation drying and quiescence. Mutant atr and atm seeds are highly resistant to aging, establishing ATM and ATR as determinants of seed viability. In response to aging, ATM delays germination, whereas atm mutant seeds germinate with extensive chromosomal abnormalities. This identifies ATM as a major factor that controls germination in aged seeds, integrating progression through germination with surveillance of genome integrity. Mechanistically, ATM functions through control of DNA replication in imbibing seeds. ATM signaling is mediated by transcriptional control of the cell cycle inhibitor SIAMESE-RELATED 5, an essential factor required for the aging-induced delay to germination. In the soil seed bank, seeds exhibit increased transcript levels of ATM and ATR, with changes in dormancy and germination potential modulated by environmental signals, including temperature and soil moisture. Collectively, our findings reveal physiological functions for these sensor kinases in linking genome integrity to germination, thereby influencing seed quality, crucial for plant survival in the natural environment and sustainable crop production.

Biochemical Changes Associated with Germinating Rice Grains and Germination Improvement

Directory of Open Access Journals (Sweden)

Subajiny VELUPPILLAI

2009-09-01

Full Text Available To determine biochemical changes during the germination of rice grains (Oryza sativa L. subsp. indica var. Mottaikaruppan and to improve germination rate using gibberellic acid and surfactants [sodium dodecyl sulfate (SDS (1.0 g/L and Triton-X−100 (1.0 mL/L], whole rice grains soaked in distilled water for 12 h at 30°C were germinated in the dark at 30°C for five days. The highest germination rate (77.1% was obtained on the 5th day. An increase in the content of reducing sugars from 7.3 to 58.1 mg/g DM (dry matter was observed from the 1st day of germination. Free amino acids and soluble protein contents increased to 3.69 and 5.29 mg/g DM, respectively on the 5th day of germination. Total protein content decreased from 100.5 to 91.0 g/kg DM during germination. Increases in amylolytic (1.1 to 190.0 U/g DM and proteolytic (0 to 0.12 U/g DM activities were observed during germination. Effects of different concentrations of gibberellic acid on the germination of rice grains were evaluated and 0.1 g/L was found to promote germination. When effects of gibberellic acid (0.1 g/L and surfactants were evaluated individually and together, higher germination rate was observed in the control experiment (grains germinated in distilled water, whereas giberellic acid and surfactants decreased the germination rate. Therefore, the flour obtained from the grains germinated for four days using distilled water to obtain high content of soluble materials and enzyme activities can be used in preparation of bakery items.

Effect of reduced light and low oxygen concentration on germination, growth and establishment of some plants

DEFF Research Database (Denmark)

Yasin, Muhammad

Many abiotic factors effect plants germination, growth, and development. This Ph.D. study elucidates the effect of reduced light, low oxygen and seed dormancy on germination and growth of some weed species, field crops and vegetables. One study describes the growth and developmental responses...... of some common, invasive and rare weed species to reduced light levels in greenhouse experiments. The seed germination response of some weed species, field crops, and vegetables to different oxygen concentrations was also quantified in the laboratory experiments. The effect of east-west (EW) and north...

Seed germination of Phillyrea angustifolia L., a species of difficult propagation

Energy Technology Data Exchange (ETDEWEB)

Mira, Sara; Arnal, Alberto; Pérez-García, Félix

2017-11-01

Aim of study: The purpose was to determine the type of dormancy and the optimal germination conditions of Phillyrea angustifolia (Oleaceae) seeds. Area of study: Germination requirements of P. angustifolia seeds collected from wild plants growing in the province of Ávila (Central Spain) were studied. Materials and methods: Seed water uptake was measured. Seeds with and without an endocarp were germinated at different temperatures, and several treatments were tested. Main results: The lignified endocarp interferes mechanically with the emergence of the radicle, and the treatments that achieved the highest germination percentages were the total removal of the endocarp with pliers (84%) or the immersion in liquid nitrogen for 1 min (97%). Scarification with concentrated sulphuric acid did not significantly increase germination compared to the control seeds, and treatments with dry heat or wet heat were detrimental to seed germination. The optimum temperature for germination was 15 ºC. A pre-sowing treatment of soaking in distilled water for 24 h slightly increased germination speed. Neither cold stratification at 5 ºC nor soaking in a gibberellic acid solution improved seed germination. Research highlights: Phillyrea angustifolia seeds have physiological dormancy – that is, the embryo does not have enough growth potential to overcome the mechanical restriction of the lignified endocarp. The seeds do not exhibit physical dormancy, given their water-permeable lignified endocarp. Our results suggest that the optimum germination protocol for P. angustifolia would be the total removal of the endocarp or immersion in liquid nitrogen for 1 min, followed by immersion in distilled water for 24 h and then seed incubation at 15 ºC in light or darkness.

Germination of beans and snap beans seed

Directory of Open Access Journals (Sweden)

Zdravković Milan

2000-01-01

Full Text Available The aim of this study was to investigate germination of good bean seed of the variety Galeb and the bad bean seed of the same variety. We were also interested in germination of bean and snap bean seed damaged by grain weevil, and in germination of the seed treated by freezing which was aimed at controlling grain weevil by cold. We also recorded the differences between bean and snap bean seed, which was or was not treated by freezing in laboratory conditions. This investigation was carried out by applying the two factorial block system. The obtained results were evaluated by the variance analysis and x2 test These results suggest that the bean seed of a bad fraction had low levels of germination, but still it was present. Although the seed of good appearance was carefully selected, germination was slightly lower than it should have been. The seed with the large amount of grain weevils performed a high level germination in laboratory conditions. There were no differences in germination between the seed injured by grain weevil either in beans or in snap beans. As for the seed treated or untreated by freezing, there also were no differences between beans and snap beans. .

Imbibition and germination in the seeds of Heliotropium supinum L.

Directory of Open Access Journals (Sweden)

Ramesh C. Bhatia

2014-01-01

Full Text Available Imbibition in the seeds of Heliotropium supinum L. varies under different temperatures. The optimum temperatures for imbibition and germination are also different. For germination 39% imbibition is essential, and this capability is achieved by 12-week-old seeds. With duration of dry storage imbibition increases. The imbibition and germination percentages decline on re-dry storage of seeds after embeding in mud. A soil moisture of 44% is optimal for germination. A correlation exists between imbibition and germination.

The oxygen requirement of germinating flax seeds

Science.gov (United States)

Kuznetsov, O.; Hasenstein, K.

Experiments for earth orbit are typically prepared on the ground and often germinated in orbit in order to study gravity effects on developing seedlings. Germination requires the breakdown of storage compounds and respiration. In orbit the formation of a water layer around the seed may further limit oxygen availability. Therefore, the oxygen content of the available gas volume is one of the limiting factors for seed germination. In preparation for an upcoming shuttle experiment (MICRO on STS-107) we studied germination and growth of flax (Linum usitatissimum L.) seedlings in the developed hardware. We tested per seed chamber (gas volume = 14 mL, O2 = 2.9 mL) between 4 to 32 seeds glued to germination paper by 1% (w/v) gum guar. A lexan cover and a gasket hermetically sealed each of the eight chambers. For imbibition of the seeds a previously optimized amount of distilled water was dispensed through sealed inlets. The seedlings were allowed to grow for either 32 to 48 h on a clinostat or without microgravity simulation. Then their root length was measured. With 32 seeds per chamber, four times the intended number of seeds for the flight, the germination rate decreased from 94 to 69%, and the root length was reduced by 20%. Experiments on the germination and root length in controlled atmospheres (5, 10, 15 and 21% O2 ) suggest that germination and growth for two days requires about 200 :l of O (1 mL air) per seed. Our2 experiments correlate oxygen dependency from seed mass and germination temperature, and analyze accumulation of gaseous metabolites (supported by NASA grant NAG10-0190).

Germinated Brown Rice Attenuates Atherosclerosis and Vascular Inflammation in Low-Density Lipoprotein Receptor-Knockout Mice.

Science.gov (United States)

Zhao, Ruozhi; Ghazzawi, Nora; Wu, Jiansu; Le, Khuong; Li, Chunyang; Moghadasian, Mohammed H; Siow, Yaw L; Apea-Bah, Franklin B; Beta, Trust; Yin, Zhengfeng; Shen, Garry X

2018-05-02

The present study investigates the impact of germinated brown rice (GBR) on atherosclerosis and the underlying mechanism in low-density lipoprotein receptor-knockout (LDLr-KO) mice. The intensity of atherosclerosis in aortas of LDLr-KO mice receiving diet supplemented with 60% GBR (weight/weight) was significantly less than that in mice fed with 60% white rice (WR) or control diet ( p mice fed with WR diet was significantly more than that from mice receiving the control diet ( p mice in comparison to the WR diet ( p mice compared to WR. The anti-atherosclerotic effect of GBR in LDLr-KO mice at least in part results from its anti-inflammatory activity.

INFLUENCE OF TEMPERATURE AND RELATIVE HUMIDITY ON GRAIN MOISTURE, GERMINATION AND VIGOUR OF THREE WHEAT CULTIVARS DURING ONE YEAR STORAGE

Directory of Open Access Journals (Sweden)

Ivica Strelec

2010-12-01

Full Text Available Changes in grain moisture, germination and vigour of three wheat cultivars packed in paper bags and stored for one year under four different conditions of environmental temperature and relative humidity (RH were investigated. During the first ninety days of storage significant reduction in grain moisture content of 4, 2.5 and 0.9 %, respectively, under 40 °C, 25 °C and 4 °C and RH of 45 % occurred. Subsequently grain moisture remained constant until the end of storage. Seeds of examined cultivars lost their germination ability and vigour only under elevated storage temperatures. Germination and vigour loss after one year of storage differed between cultivars being higher for seeds kept under 40°C, RH = 45% (35-85 % and 55-94 %, respectively, than under 25°C, RH = 45 % (10-20 % and 15-22 %, respectively. Obtained data indicate significant influence of storage conditions on moisture content, germination and vigour changes during storage of wheat seeds, as well as varietal dependence of seed viability.

[Study on conditions of seed germination of Cistanche].

Science.gov (United States)

Qiao, Xue-Yi; Wang, Hua-Lei; Guo, Yu-Hai

2007-09-01

To study the effect of fluridone concentration, stimulating period, temperature and salt on the seed germination of three species of Cistanche. The seeds were cultured in Petri dish, and the germination percentage was counted. The highest germination percentage was observed in Cistanche tubulosa, C. deserticola, C. sala seeds pre-treated by 0.1 mg x L(-1) fluridone for 24-29 h. The optimal temperature for the seeds germination of three species of Cistanche was at 20-30 degrees C, and the seeds did not germinate at sub-or supraoptimal temperatures (5 and 35 degrees C). The salt tolerance of C. sala seeds was strong, and the critical value of NaCl concentration was 0.04 mol x L(-1). By contrast, C. tubulosa and C. deserticola seeds were more sensitive to the salt stress, the critical value of NaCl concentration was 0.02 mol x L(-1). The optimal germination condition and the method of testing germination percentage of three species of Cistanche seeds are as follow: the seeds are pre-treated by 0.1 mg x L(-1) fluridone for 24 h and then cultured at 20-30 degrees C in salt solution which concentration is lower than 0.02 mol x L(-1).

Reduced seed germination in Arabidopsis over-expressing SWI/SNF2 ATPase genes.

Science.gov (United States)

Leeggangers, Hendrika A C F; Folta, Adam; Muras, Aleksandra; Nap, Jan-Peter; Mlynarova, Ludmila

2015-02-01

In the life of flowering plants, seed germination is a critical step to ensure survival into the next generation. Generally the seed prior to germination has been in a dormant state with a low rate of metabolism. In the transition from a dormant seed to a germinating seed, various epigenetic mechanisms play a regulatory role. Here, we demonstrate that the over-expression of chromatin remodeling ATPase genes (AtCHR12 or AtCHR23) reduced the frequency of seed germination in Arabidopsis thaliana up to 30% relative to the wild-type seeds. On the other hand, single loss-of-function mutations of the two genes did not affect seed germination. The reduction of germination in over-expressing mutants was more pronounced in stress conditions (salt or high temperature), showing the impact of the environment. Reduced germinations upon over-expression coincided with increased transcript levels of seed maturation genes and with reduced degradation of their mRNAs stored in dry seeds. Our results indicate that repression of AtCHR12/23 gene expression in germinating wild-type Arabidopsis seeds is required for full germination. This establishes a functional link between chromatin modifiers and regulatory networks towards seed maturation and germination. © 2014 Scandinavian Plant Physiology Society.

pre-germination treatments in castor seeds, cultivar IAC 226

International Nuclear Information System (INIS)

Costa Nobre, Danubia Aparecida; Gomes Damascena, Joyce; Marcia, Andreia; Santos de Souza, David; Pereira dos Santos, Marlucia; Rodrigues Pereira, Adriana; Goncalves Pereira, Cassio

2013-01-01

The present study aimed to evaluate the efficiency of different pre-germination treatments in castor beans, IAC 226. The experimental design was completely randomized in a factorial 4 x 4 (four temperatures and four immersion times), with four replications. Pre-germination treatments were: immersion in water at room temperature (25 Celsius degrade) and immersion in hot water at temperatures of 60, 70 and 80 Celsius degrade for 2, 4, 6 and 8 minutes. Water content of the seeds was determined before treatments. Before and after each treatment, seeds were subjected to germination test; 20-30 Celsius degrade alternating temperature, determining the percentages of normal and abnormal seedlings, dormant and dead seeds. Independent of time, immersion in 70 Celsius degrade, water was the most efficient treatment for accelerating germination of castor bean cultivar IAC 226.

Germination of Chenopodium Album in Response to Microwave Plasma Treatment

International Nuclear Information System (INIS)

Sera, Bozena; Stranak, Vitezslav; Sery, Michal; Spatenka, Petr; Tichy, Milan

2008-01-01

The seeds of Lamb's Quarters (Chenopodium album agg.) were stimulated by low-pressure discharge. The tested seeds were exposed to plasma discharge for different time durations (from 6 minutes to 48 minutes). Germination tests were performed under specified laboratory conditions during seven days in five identical and completely independent experiments. Significant differences between the control and plasma-treated seeds were observed. The treated seeds showed structural changes on the surface of the seat coat. They germinated faster and their sprout accretion on the first day of seed germination was longer. Germination rate for the untreated seeds was 15% while it increased approximately three times (max 55%) for seeds treated by plasma from 12 minutes to 48 minutes.

Servo-control for maintaining abdominal skin temperature at 36C in low birth weight infants.

Science.gov (United States)

Sinclair, J C

2002-01-01

Randomized trials have shown that the neonatal mortality rate of low birth-weight babies can be reduced by keeping them warm. For low birth-weight babies nursed in incubators, warm conditions may be achieved either by heating the air to a desired temperature, or by servo-controlling the baby's body temperature at a desired set-point. In low birth weight infants, to determine the effect on death and other important clinical outcomes of targeting body temperature rather than air temperature as the end-point of control of incubator heating. Standard search strategy of the Cochrane Neonatal Review Group. Searches were made of the Cochrane Controlled Trials Register (CCTR) (Cochrane Library, Issue 4, 2001) and MEDLINE, 1966 to November 2001. Randomized or quasi-randomized trials which test the effects of having the heat output of the incubator servo-controlled from body temperature compared with setting a constant incubator air temperature. Trial methodologic quality was systematically assessed. Outcome measures included death, timing of death, cause of death, and other clinical outcomes. Categorical outcomes were analyzed using relative risk and risk difference. Meta-analysis assumed a fixed effect model. Two eligible trials were found. In total, they included 283 babies and 112 deaths. Compared to setting a constant incubator air temperature of 31.8C, servo-control of abdominal skin temperature at 36C reduces the neonatal death rate among low birth weight infants: relative risk 0.72 (95% CI 0.54, 0.97); risk difference -12.7% (95% CI -1.6, -23.9). This effect is even greater among VLBW infants. During at least the first week after birth, low birth weight babies should be provided with a carefully regulated thermal environment that is near the thermoneutral point. For LBW babies in incubators, this can be achieved by adjusting incubator temperature to maintain an anterior abdominal skin temperature of at least 36C, using either servo-control or frequent manual

Germination, carbohydrate composition and vigor of cryopreserved Caesalpinia echinata seeds

Directory of Open Access Journals (Sweden)

Rafael Fonsêca Zanotti

2012-10-01

Full Text Available The present study investigated the germination and vigor of Caesalpinia echinata (Brazilwood seeds stored at negative temperatures. Recently harvested seeds were cryopreserved at -18º or -196ºC and periodically evaluated for germination, seed vigor and carbohydrate composition. The temperatures did not influence the germination percentages or vigor. The germination percentage decreased from 88% in recently harvested seeds to 60% after 730 days of storage. The different temperature and storage times tested did not affect the vigor seed germination as indicated by the measures of plant growth and survival. The different temperatures used did not cause changes in the carbohydrate composition. The tegument cell walls were rich in lignin, arabinose and xylose. The cytoplasm of the cotyledons and embryos had high levels of glucose, fructose, and sucrose. The cryopreservation technique here presented was effective in the conservation of Brazilwood seeds for the medium term.

Laboratory evaluation of temperature effects on the germination and growth of entomopathogenic fungi and on their pathogenicity to two aphid species.

Science.gov (United States)

Yeo, Helen; Pell, Judith K; Alderson, Peter G; Clark, Suzanne J; Pye, Barry J

2003-02-01

As part of an approach to select potential mycoinsecticides for aphid biocontrol, we investigated the effects of temperature on the growth, germination and pathogenicity of some hyphomycete fungi. Commercially available mycoinsecticides (based on Beauveria bassiana (Balsamo) Vuillemin and Verticillium lecanii (Zimmermann) Viegas) and other isolates of B bassiana, V lecanii, Metarhizium anisopliae (Metschnikoff) Sorokin and Paecilomyces fumosoroseus (Wize) Brown & Smith were evaluated. The rate of in vitro conidial germination of all isolates was slower at 10 and 15 degrees C than at 20 and 25 degrees C. Similarly, in vitro growth of most isolates was adversely affected at 10 and 15 degrees C. The greatest reduction at 10 degrees C in rates of conidial germination and colony growth, compared with other temperatures, was for M anisopliae isolates. Germination of V lecanii (isolate HRI 1.72) was fastest at 10 degrees C compared with the other fungi. It was also the most pathogenic of three isolates tested against Aphis fabae Scopoli and Myzus persicae Sulzer at 10, 18 and 23 degrees C. Generally, A fabae was more susceptible than M persicae to infection by the fungal isolates tested. A significant interaction between aphid species and temperature indicated that the pathogenic nature of an isolate was dependent not only on the target aphid species but also the temperature conditions of the bioassay. The series of studies, detailed above, allowed a temperature profile to be formed for the different isolates. Verticillium lecanii isolate HRI 1.72 (commercialised as Vertalec) was the most promising isolate selected from results of the series of experiments. Temperature profiles in conjunction with infectivity assays can be useful in selecting appropriate isolates for a particular thermal environment.

Maternal habitat affects germination requirements of Anabasis setifera, a succulent shrub of the Arabian deserts

Directory of Open Access Journals (Sweden)

Ali El-Keblawy

2016-03-01

Full Text Available The effects of maternal habitat on light and temperature requirements during germination were assessed for the succulent desert shrub Anabasis setifera. Seeds were collected from the Mediterranean habitats of Egypt and the hyper-arid subtropical habitats of the United Arab Emirates (UAE. Seeds from the two populations were germinated in three temperature treatments in both a light/dark regime and continuous darkness. Seeds from the Egyptian population germinated significantly greater and faster than those of UAE. Seeds stored for four months at room temperatures have little dormancy and germinate at wide range of temperatures and light conditions, but seeds stored four months in the natural habitat lost their ability to germinate and rotted 10 days after incubation. The germination response to temperature depended on the habitat type. Seeds of the Egyptian population attained a significantly greater germination at lower temperatures, compared with seeds from the UAE population, but there was no difference in germination between the two populations at higher temperatures. Germination of A. setifera was very fast; most seeds germinated within four days. These results reflect the adaptive strategy of germination in both populations, and may help explain the wide distribution of this species in different climatic regions.

EFFECT OF DIFFERENT SUBSTRATES ON THE GERMINATION OF SEEDS CEDRELA FISSILIS VELLOZO (MELIACEAE

Directory of Open Access Journals (Sweden)

R. Marchezan

2017-12-01

Full Text Available The present study was to evaluate the Cedar seed germination and the handling of different substrates to elucidate what is the best condition for the species. The experiment was conducted in the laboratory, without control of incidence of light or temperature, leaving them as much as possible under natural conditions. Treatments consisted of four treatments and four repetitions, each repetition consisted of 10 subrepetitions, totaling 40 units (plastic cups per treatment. Seeds were sown with two seeds per cup. The characteristics evaluated were the percentage of germination and germination speed index (GSI. It is concluded this way that the seeds subjected to the earth and sand worked to conduct tests for germination cedar seeds were those that gave higher percentages of germination and IVG. While the substrates, commercial and land forest were considered unfavorable for conducting germination tests for cedar seeds.

Influence de quelques facteurs environnementaux sur la germination d'Euphorbia heterophylla L. (Euphorbiaceae

Directory of Open Access Journals (Sweden)

Ipou Ipou, J.

2004-01-01

Full Text Available Influence of some Environmental Factors on Euphorbia heterophylla L. (Euphorbiaceae Seeds Germination. In Ivory Coast, Euphorbia heterophylla appears as a weed in cotton fields. Effects of temperature, light and burying levels on its seed germination were tested. Temperature effects were monitored by means of 4 procedures, using a range of temperatures between 20 and 35 °C. The germination latency period can vary between 1 and 2 days, according to the temperature. After 4 days, germination rates were not longer related to temperature and were very similar. Germination can not happen without light. In order to measure the effect of burying levels, six series of 100 seeds were buried; the first at ground level, the others respectively 2, 4, 6, 8 and 9 cm deeper. Optimal germination rates were found for seeds that were buried between 0 and 6 cm.

The use of transcription inhibitors in the study of the mechanism of abscisic acid action in germinating triticale caryopses

Directory of Open Access Journals (Sweden)

Stanisław Weidner

2014-01-01

Full Text Available The study was conducted on germinating triticale (var. Grado caryopses. The purpose of the experiments was to compare the effect of selected inhibitors of transcription with the action of abscisic acid during germination of caryopses. The following inhibitors were used: α-amanitin, cordycepin, cycloheximide and 5-fluorouracil. Studied were the synthesis of total and polyribosomal RNA, the process of polyribosome formation and the synthesis of ribosomal proteins. The effect of exogenous ABA, especially in the early stages of germination, was not similar to any of the four above inhibitors of transcription. After 12 h of imbibition at a lowered temperature and 3 h of germination, ABA caused a relatively low level of inhibition of RNA synthesis, whereas all of the inhibitors used halted RNA synthesis in embryos by about 50-60%. After 6 h of germination, the same proportion of polyribosomes in the total ribosome fraction (46% was found in both the embryos from the control sample and treated with ABA. The use of inhibitors brought this figure down to below 40%. The conclusion is drawn that in the early stages of germination, regulation of protein synthesis by ABA in triticale caryopses must occur on a level other than transcription.

Abscisic acid in the thermoinhibition of lettuce seed germination and enhancement of its catabolism by gibberellin.

Science.gov (United States)

Gonai, Takeru; Kawahara, Shusuke; Tougou, Makoto; Satoh, Shigeru; Hashiba, Teruyoshi; Hirai, Nobuhiro; Kawaide, Hiroshi; Kamiya, Yuji; Yoshioka, Toshihito

2004-01-01

Germination of lettuce (Lactuca sativa L. cv. 'Grand Rapids') seeds was inhibited at high temperatures (thermoinhibition). Thermoinhibition at 28 degrees C was prevented by the application of fluridone, an inhibitor of abscisic acid (ABA) biosynthesis. At 33 degrees C, the sensitivity of the seeds to ABA increased, and fluridone on its own was no longer effective. However, a combined application of fluridone and gibberellic acid (GA3) was able to restore the germination. Exogenous GA3 lowered endogenous ABA content in the seeds, enhancing catabolism of ABA and export of the catabolites from the intact seeds. The fluridone application also decreased the ABA content. Consequently, the combined application of fluridone and GA3 decreased the ABA content to a sufficiently low level to allow germination at 33 degrees C. There was no significant temperature-dependent change in endogenous GA1 contents. It is concluded that ABA is an important factor in the regulation of thermoinhibition of lettuce seed germination, and that GA affects the temperature responsiveness of the seeds through ABA metabolism.

Germination and inactivation of Bacillus coagulans and Alicyclobacillus acidoterrestris spores by high hydrostatic pressure treatment in buffer and tomato sauce.

Science.gov (United States)

Vercammen, Anne; Vivijs, Bram; Lurquin, Ine; Michiels, Chris W

2012-01-16

Acidothermophilic bacteria like Alicyclobacillus acidoterrestris and Bacillus coagulans can cause spoilage of heat-processed acidic foods because they form spores with very high heat resistance and can grow at low pH. The objective of this work was to study the germination and inactivation of A. acidoterrestris and B. coagulans spores by high hydrostatic pressure (HP) treatment at temperatures up to 60°C and both at low and neutral pH. In a first experiment, spores suspended in buffers at pH 4.0, 5.0 and 7.0 were processed for 10min at different pressures (100-800MPa) at 40°C. None of these treatments caused any significant inactivation, except perhaps at 800MPa in pH 4.0 buffer where close to 1 log inactivation of B. coagulans was observed. Spore germination up to about 2 log was observed for both bacteria but occurred mainly in a low pressure window (100-300MPa) for A. acidoterrestris and only in a high pressure window (600-800MPa) for B. coagulans. In addition, low pH suppressed germination in A. acidoterrestris, but stimulated it in B. coagulans. In a second series of experiments, spores were treated in tomato sauce of pH 4.2 and 5.0 at 100 - 800MPa at 25, 40 and 60°C for 10min. At 40°C, results for B. coagulans were similar as in buffer. For A. acidoterrestris, germination levels in tomato sauce were generally higher than in buffer, and showed little difference at low and high pressure. Remarkably, the pH dependence of A. acidoterrestris spore germination was reversed in tomato sauce, with more germination at the lowest pH. Furthermore, HP treatments in the pH 4.2 sauce caused between 1 and 1.5 log inactivation of A. acidoterrestris. Germination of spores in the high pressure window was strongly temperature dependent, whereas germination of A. acidoterrestris in the low pressure window showed little temperature dependence. When HP treatment was conducted at 60°C, most of the germinated spores were also inactivated. For the pH 4.2 tomato sauce, this

Effect of Different Dormancy Breaking Treatments on Seed Germination of Salsifis (Teragopogon collinus and Flixweed ( Descurainia Sophia as Two Weed Species

Directory of Open Access Journals (Sweden)

marzie mazhari

2017-01-01

Full Text Available Introduction: Weeds limit crops growth, development and yield through adjacency and competing and seed dormancy is a problem in controlling of weeds. Man has been always tried to optimize crop yield through weeds controlling. Weeds seed bank in the soil can affected weed management and their control methods. So identifying seed bank characters has important role in choice of management methods in seeds of many plant species which cannot germinate despite favorable environmental conditions. Main reasons for this problem, which is termed as seed dormancy, are hard and impermeable seed coat and presence of immature or dormant embryo. To break dormancy, a variety of methods are in vogue worldwide these days. Of all different methods of breaking dormancy, treatment of seed with certain chemicals including different types of plant growth regulators (PGRs is contemplated as the most effective one. Gibberellic acid (GA3 is the most widely used PGR to improve seed germination in different plant species. Also, nitrate (such as KNO3 clearly stimulates the germination of dormant seeds. KNO3 is the most widely used chemical for promoting germination. Solutions of KNO3 are common in routine germination testing and are recommended by the Association of Official Seed Analysts and the International Seed Testing Association (ISTA for germination tests of many species.Stratification refers to the method of placing seeds in layers alternating with layers of a moisture retaining medium, such as sand, peat or vermiculite, and keeping them at a cool temperature for a certain period, but it varies considerably from species to species. The combination of high moisture and low temperature appears to trigger off biochemical changes which transform complex food substances into simpler forms utilized by the embryo when it renews growth at germination. The use of the word “stratification” has recently been extended to include all forms of cold, moist treatment whether or

Germination Shifts of C3 and C4 Species under Simulated Global Warming Scenario

Science.gov (United States)

Zhang, Hongxiang; Yu, Qiang; Huang, Yingxin; Zheng, Wei; Tian, Yu; Song, Yantao; Li, Guangdi; Zhou, Daowei

2014-01-01

Research efforts around the world have been increasingly devoted to investigating changes in C3 and C4 species' abundance or distribution with global warming, as they provide important insight into carbon fluxes and linked biogeochemical cycles. However, changes in the early life stage (e.g. germination) of C3 and C4 species in response to global warming, particularly with respect to asymmetric warming, have received less attention. We investigated germination percentage and rate of C3 and C4 species under asymmetric (+3/+6°C at day/night) and symmetric warming (+5/+5°C at day/night), simulated by alternating temperatures. A thermal time model was used to calculate germination base temperature and thermal time constant. Two additional alternating temperature regimes were used to test temperature metrics effect. The germination percentage and rate increased continuously for C4 species, but increased and then decreased with temperature for C3 species under both symmetric and asymmetric warming. Compared to asymmetric warming, symmetric warming significantly overestimated the speed of germination percentage change with temperature for C4 species. Among the temperature metrics (minimum, maximum, diurnal temperature range and average temperature), maximum temperature was most correlated with germination of C4 species. Our results indicate that global warming may favour germination of C4 species, at least for the C4 species studied in this work. The divergent effects of asymmetric and symmetric warming on plant germination also deserve more attention in future studies. PMID:25137138

Germination shifts of C3 and C4 species under simulated global warming scenario.

Science.gov (United States)

Zhang, Hongxiang; Yu, Qiang; Huang, Yingxin; Zheng, Wei; Tian, Yu; Song, Yantao; Li, Guangdi; Zhou, Daowei

2014-01-01

Research efforts around the world have been increasingly devoted to investigating changes in C3 and C4 species' abundance or distribution with global warming, as they provide important insight into carbon fluxes and linked biogeochemical cycles. However, changes in the early life stage (e.g. germination) of C3 and C4 species in response to global warming, particularly with respect to asymmetric warming, have received less attention. We investigated germination percentage and rate of C3 and C4 species under asymmetric (+3/+6°C at day/night) and symmetric warming (+5/+5°C at day/night), simulated by alternating temperatures. A thermal time model was used to calculate germination base temperature and thermal time constant. Two additional alternating temperature regimes were used to test temperature metrics effect. The germination percentage and rate increased continuously for C4 species, but increased and then decreased with temperature for C3 species under both symmetric and asymmetric warming. Compared to asymmetric warming, symmetric warming significantly overestimated the speed of germination percentage change with temperature for C4 species. Among the temperature metrics (minimum, maximum, diurnal temperature range and average temperature), maximum temperature was most correlated with germination of C4 species. Our results indicate that global warming may favour germination of C4 species, at least for the C4 species studied in this work. The divergent effects of asymmetric and symmetric warming on plant germination also deserve more attention in future studies.

[Study on influence factors of seed germination and seeding growth of Lonicera macranthoides].

Science.gov (United States)

Xu, Jin; Zhang, Ying; Cui, Guang-Lin; She, Yue-Hui; Li, Long-Yun

2016-01-01

In order to improve reproductive efficiency and quality standard, the influence factors of seed germination and seeding growth of Lonicera macranthoides werew studied. The fruit and seed morphological characteristics of L. macranthoides were observed, the seed water absorbing capacity was determined, and different wet sand stratification time, temperature and germination bed treatment were set up. The effects of the parameters on seed germination and seedling growth were analysed. There was no obstacles of water absorption on L. macranthoides seed, quantity for 22 h water absorption was close to saturation. In the first 80 d, with the increase of the stratification time, seed initial germination time was shortened, germination rate and germination potential was improved. Stratification for 100 d, germination rate decreased. At 15 ℃, seed germination and seedling growth indicators were the best. The seedling cotyledon width in light was significantly higher than that in dark. Seeds on the top of paper and top of sand germination rate, germination potential, and germination index was significantly higher than that of other germination bed and mildew rate is low. The optimal conditions of seeds germination test was stratified in 4 ℃ wet sand for 80 d, 15 ℃ illuminate culture on the top of paper or top of sand. The first seeding counting time was the 4th day after beginning the test, the final time was the 23th day. The germination potential statistical time was the 13th day after beginning the test. Copyright© by the Chinese Pharmaceutical Association.

Effect of electron beam irradiation on conidial germination activity and pathogenicity of Botrytis cinerea

International Nuclear Information System (INIS)

Zhang Ting; Qiao Yongjin; Chen Zhaoliang

2011-01-01

Conidia of Botrytis cinerea were irradiated by electron beam at 0.5, 1.0, 2.0 and 3.0 kGy. The influence of electron beam on the activities of conidial germination and pathogenicity at the temperatures of 5 ℃ and 25 ℃ were tested, respectively. The results showed that the electron beam could inhibit germination of conidia and the length of germ tube of Botrytis cinerea, and delay the germination time. It could also decrease the pathogenicity obviously and higher irradiation dose showed stronger effects. Compared with control, the complete germination time of conidia extended to 5 and 9 d at the cultivate temperatures of 25 ℃ and 5 ℃, after 2 kGy of irradiation, and the germination rate was reduced 46.57% and 33.68%, respectively. The inhibition rates of germ tube were 25.12% and 74.29% when cultured 24 h. The pathogenicity of Botrytis cinerea to strawberry was reduced significantly. After 2.0 kGy irradiation and cultivate at 25 ℃ for 2 d, the disease index was 4.17 and it decreased to 15.28 after cultivation of 5 ℃ for 15 d. Electron beam treatment could inhibit the spore germination and germ tube elongation of Botrytis cinerea significantly, delayed the germination time, and reduced its pathogenicity, the higher the dose, the effect was more obvious. (authors)

Germination Response of Four Alien Congeneric Amaranthus Species to Environmental Factors.

Science.gov (United States)

Hao, Jian-Hua; Lv, Shuang-Shuang; Bhattacharya, Saurav; Fu, Jian-Guo

2017-01-01

Seed germination is the key step for successful establishment, growth and further expansion of population especially for alien plants with annual life cycle. Traits like better adaptability and germination response were thought to be associated with plant invasion. However, there are not enough empirical studies correlating adaptation to environmental factors with germination response of alien invasive plants. In this study, we conducted congeneric comparisons of germination response to different environmental factors such as light, pH, NaCl, osmotic and soil burials among four alien amaranths that differ in invasiveness and have sympatric distribution in Jiangsu Province, China. The data were used to create three-parameter sigmoid and exponential decay models, which were fitted to cumulative germination and emergence curves. The results showed higher maximum Germination (Gmax), shorter time for 50% germination (G50) and the rapid slope (Grate) for Amaranthus blitum (low-invasive) and A. retroflexus (high-invasive) compare to intermediately invasive A. spinosus and A. viridis in all experimental regimes. It indicated that germination potential does not necessarily constitute a trait that can efficiently distinguish highly invasive and low invasive congeners in four Amaranthus species. However, it was showed that the germination performances of four amaranth species were more or less correlated with their worldwide distribution area. Therefore, the germination performance can be used as a reference indicator, but not an absolute trait for invasiveness. Our results also confirmed that superior germination performance in wide environmental conditions supplementing high seed productivity in highly invasive A. retroflexus might be one of the reasons for its prolific growth and wide distribution. These findings lay the foundation to develop more efficient weed management practice like deep burial of seeds by turning over soil and use of tillage agriculture to control

Low temperature distillation

Energy Technology Data Exchange (ETDEWEB)

Vandegrift, J N; Postel, C

1929-04-09

To recover gas, oil tars, and coked residues by low temperature distillation from bituminous coals, lignites, oil shales, and the like, the raw material is fed from a hopper into a rotary retort which is zonally heated, the temperature being greatest at the discharge end. The material is heated first to a relatively low temperature, thereby removing the moisture and lighter volatiles which are withdrawn through a pipe by the suction of a pump, while the higher boiling point volatiles and fixed gases are withdrawn by suction through an outlet from the higher temperature zone. The vapors withdrawn from the opposite ends of the retort pass through separate vapor lines and condensers, and the suction in each end of the retort, caused by the pumps, is controlled by valves, which also control the location of the neutral point in the retort formed by said suction. Air and inert gas may be introduced into the retort from pipe and stack respectively through a pipe, and steam may be admitted into the high temperature zone through a pipe.

Mean germination time and germination rate of oat seeds subjected to stationary magnetic field

International Nuclear Information System (INIS)

Martinez Ramirez, Elvira; Florez Garcia, Mercedes; Carbonell, Maria Victoria; Amaya Garcia de la Escosura, Jose Manuel

2007-01-01

The objective of the present study is to determine and quantify the effect produced by stationary magnetic fields on oat seed germination (Avena sativa, L. var. c obena ) . For this purpose, seeds were exposed to a magnetic field 125 mT of 250 mT during different periods of time: 20 minutes (E1, E5), 1 hour (E2, E6), 24 hours (E3, E7), or in a conic form (E4, E8) during the whole germination process. Germination tests were carried out under laboratory conditions with cylindrical magnets to obtain the magnetic field. For magnetic treatment seed on Petri dishes were placed on magnets during time necessary for each treatment. Seeds without exposition to the magnetic field were used as control group. Parameters used for germination speed analysis were: number of germinated seeds (G), mean germination time (MGT) and necessary time for germination of 1, 10, 25, 50 and 75% of N number of speeds used for each treatment (T1, T10, T25, T50, and T75). These parameters were supplied through the software Seed calculator, as well as the corresponding germination curves. In general, from the results obtained it can be said that the time required to obtain different germination percentages was lower for seeds exposed to the magnetic field (treatments E1 and E8). Reduction in time for E1 treatment stands up with 20 a minutes-exposition-time to 125 mT. MGT obtained for seeds with magnetic treatment E1 was significantly lower (11.48%) than the control group. Parameters T1, T10, T25 were also lower for seeds submitted to treatment, obtaining reductions of 46.62 %, 24.02 % and 13.46 % respectively. Reduction in germination parameters indicates that germination speed is higher. Because parameters T1 and T10 are related to the beginning of germination, this study represents a progress in germination and a reduction in the induction phase in most of the magnetic treatments applied. Previous studies done by authors about the influence of stationary magnetic fields have shown increases in

Germination and growth of lettuce (Lactuca sativa) at low atmospheric pressure

Science.gov (United States)

Spanarkel, Robert; Drew, Malcolm C.

2002-01-01

The response of lettuce (Lactuca sativa L. cv. Waldmann's Green) to low atmospheric pressure was examined during the initial 5 days of germination and emergence, and also during subsequent growth to vegetative maturity at 30 days. Growth took place inside a 66-l-volume low pressure chamber maintained at 70 kPa, and plant response was compared to that of plants in a second, matching chamber that was at ambient pressure (approximately 101 kPa) as a control. In other experiments, to determine short-term effects of low pressure transients, plants were grown at ambient pressure until maturity and then subjected to alternating periods of 24 h of low and ambient atmospheric pressures. In all treatments the partial pressure of O2 was maintained at 21 kPa (approximately the partial pressure in air at normal pressure), and the partial pressure of CO2 was in the range 66.5-73.5 Pa (about twice that in normal air) in both chambers, with the addition of CO2 during the light phase. With continuous exposure to low pressure, shoot and root growth was at least as rapid as at ambient pressure, with an overall trend towards slightly greater performance at the lower pressure. Dark respiration rates were greater at low pressure. Transient periods at low pressure decreased transpiration and increased dark respiration but only during the period of exposure to low pressure. We conclude that long-term or short-term exposure to subambient pressure (70 kPa) was without detectable detriment to vegetative growth and development.

Thermal buffering capacity of the germination phenotype across the environmental envelope of the Cactaceae.

Science.gov (United States)

Seal, Charlotte E; Daws, Matthew I; Flores, Joel; Ortega-Baes, Pablo; Galíndez, Guadalupe; León-Lobos, Pedro; Sandoval, Ana; Ceroni Stuva, Aldo; Ramírez Bullón, Natali; Dávila-Aranda, Patricia; Ordoñez-Salanueva, Cesar A; Yáñez-Espinosa, Laura; Ulian, Tiziana; Amosso, Cecilia; Zubani, Lino; Torres Bilbao, Alberto; Pritchard, Hugh W

2017-12-01

Recruitment from seeds is among the most vulnerable stage for plants as global temperatures change. While germination is the means by which the vast majority of the world's flora regenerate naturally, a framework for accurately predicting which species are at greatest risk of germination failure during environmental perturbation is lacking. Taking a physiological approach, we assess how one family, the Cactaceae, may respond to global temperature change based on the thermal buffering capacity of the germination phenotype. We selected 55 cactus species from the Americas, all geo-referenced seed collections, reflecting the broad environmental envelope of the family across 70° of latitude and 3700 m of altitude. We then generated empirical data of the thermal germination response from which we estimated the minimum (T b ), optimum (T o ) and ceiling (T c ) temperature for germination and the thermal time (θ 50 ) for each species based on the linearity of germination rate with temperature. Species with the highest T b and lowest T c germinated fastest, and the interspecific sensitivity of the germination rate to temperature, as assessed through θ 50 , varied tenfold. A left-skewed asymmetry in the germination rate with temperature was relatively common but the unimodal pattern typical of crop species failed for nearly half of the species due to insensitivity to temperature change at T o . For 32 fully characterized species, seed thermal parameters correlated strongly with the mean temperature of the wettest quarter of the seed collection sites. By projecting the mean temperature of the wettest quarter under two climate change scenarios, we predict under the least conservative scenario (+3.7°C) that 25% of cactus species will have reduced germination performance, whilst the remainder will have an efficiency gain, by the end of the 21st century. © 2017 John Wiley & Sons Ltd.

Disentangling plant establishment in sandy coastal systems: biotic and abiotic factors that determine Allagoptera arenaria (Arecaceae germination

Directory of Open Access Journals (Sweden)

Luis Fernando Tavares de Menezes

2017-10-01

Full Text Available ABSTRACT Germination rate and establishment success of plants in harsh environments depend on the ability of seeds to withstand unfavorable environmental conditions and avoid predators. Brazilian coastal plains, known as restinga, are subject to environmental factors that seriously limit plant establishment and survival (e.g. salinity, desiccation, oligotrophy, flooding, high temperature and radiation levels. We tested, both in field and laboratory experiments, conditions for germination and establishment of Allagoptera arenaria, a palm tree often found in restinga ecosystems of southeastern Brazil, and which have a principal role in plant community dynamics. Our results showed that the absence of mesocarp, high radiation exposure, and temperature were the main drivers of seed germination. In the field, the highest germination rate was linked to nude seeds buried in open areas. High temperatures and/or predation damaged seeds that remained on the soil surface, especially if they were close to the mother plant and alongside dung piles made by dispersers. Under controlled conditions, seeds exhibited optimum germination at 35 ºC. Therefore, the germination and establishment of A. arenaria depend as much on environmental conditions as on a network of interactions including vertebrates and invertebrates, which allow this species to colonize harsh, open areas in restinga ecosystems.

Monte Carlo simulation of the seed germination process

International Nuclear Information System (INIS)

Gladyszewska, B.; Koper, R.

2000-01-01

Paper presented a mathematical model of seed germination process based on the Monte Carlo method and theoretical premises resulted from the physiology of seed germination suggesting three consecutive stages: physical, biochemical and physiological. The model was experimentally verified by determination of germination characteristics for seeds of ground tomatoes, Promyk cultivar, within broad range of temperatures (from 15 to 30 deg C)

Behavior of Clostridium perfringens at low temperatures

NARCIS (Netherlands)

Jong, de A.E.I.; Rombouts, F.M.; Beumer, R.R.

2004-01-01

Refrigerated storage is an important step in the preparation of foods and inadequate storage is one of the main causes of food poisoning outbreaks of Clostridium perfringens. Therefore, growth and germination characteristics of C. perfringens in a temperature range of 3-42 degreesC were determined

Seed and Germination Characteristics of 20 Amazonian Liana Species

Directory of Open Access Journals (Sweden)

Mareike Roeder

2013-01-01

Full Text Available Lianas are an important component of tropical forests, and may reach their highest densities in disturbed areas. However, information on seed and germination characteristics is scarce. Twenty Amazon liana species were screened for their germination characteristics, including light dependence, tolerance of desiccation and of alternating temperatures; these characteristics are considered important for the germination success in areas with relatively open canopies. Between 31–1,420 seeds per species were available, as 15 species seeds came from one mother plant. We studied seed biometry and conducted germination trials with fresh seeds (12 h light daily, or dark and desiccated seeds at 25 °C. Germination at alternating temperatures (20/30 °C, 15/35 °C was analyzed for nine species. Of the 20 species, eight species with the largest seeds had desiccation sensitive seeds; this is the first record for species of four genera and one family, where only desiccation tolerant seeds are otherwise recorded. Light-dependent germination was found in three species (0.01–0.015 g and is the first record for two; however, results were based on seeds from one plant per species. Alternating temperatures of 15/35 °C decreased final germination of four out of nine species, and response to 20/30 °C cycles varied compared to constant 25 °C. Seed and germination characteristics of the species ranged from pioneer to climax traits indicating that establishment of lianas from seeds may be confined to species specific niches.

The mechanism underlying fast germination of tomato cultivar LA2711.

Science.gov (United States)

Yang, Rongchao; Chu, Zhuannan; Zhang, Haijun; Li, Ying; Wang, Jinfang; Li, Dianbo; Weeda, Sarah; Ren, Shuxin; Ouyang, Bo; Guo, Yang-Dong

2015-09-01

Seed germination is important for early plant morphogenesis as well as abiotic stress tolerance, and is mainly controlled by the phytohormones abscisic acid (ABA) and gibberellic acid (GA). Our previous studies identified a salt-tolerant tomato cultivar, LA2711, which is also a fast-germinating genotype, compared to its salt-sensitive counterpart, ZS-5. In an effort to further clarify the mechanism underlying this phenomenon, we compared the dynamic levels of ABA and GA4, the transcript abundance of genes involved in their biosynthesis and catabolism as well as signal transduction between the two cultivars. In addition, we tested seed germination sensitivity to ABA and GAs. Our results revealed that insensitivity of seed germination to exogenous ABA and low ABA content in seeds are the physiological mechanisms conferring faster germination rates of LA2711 seeds. SlCYP707A2, which encodes an ABA catabolic enzyme, may play a decisive role in the fast germination rate of LA2711, as it showed a significantly higher level of expression in LA2711 than ZS-5 at most time points tested during germination. The current results will enable us to gain insight into the mechanism(s) regarding seed germination of tomato and the role of fast germination in stress tolerance. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Germination shifts of C3 and C4 species under simulated global warming scenario.

Directory of Open Access Journals (Sweden)

Hongxiang Zhang

Full Text Available Research efforts around the world have been increasingly devoted to investigating changes in C3 and C4 species' abundance or distribution with global warming, as they provide important insight into carbon fluxes and linked biogeochemical cycles. However, changes in the early life stage (e.g. germination of C3 and C4 species in response to global warming, particularly with respect to asymmetric warming, have received less attention. We investigated germination percentage and rate of C3 and C4 species under asymmetric (+3/+6°C at day/night and symmetric warming (+5/+5°C at day/night, simulated by alternating temperatures. A thermal time model was used to calculate germination base temperature and thermal time constant. Two additional alternating temperature regimes were used to test temperature metrics effect. The germination percentage and rate increased continuously for C4 species, but increased and then decreased with temperature for C3 species under both symmetric and asymmetric warming. Compared to asymmetric warming, symmetric warming significantly overestimated the speed of germination percentage change with temperature for C4 species. Among the temperature metrics (minimum, maximum, diurnal temperature range and average temperature, maximum temperature was most correlated with germination of C4 species. Our results indicate that global warming may favour germination of C4 species, at least for the C4 species studied in this work. The divergent effects of asymmetric and symmetric warming on plant germination also deserve more attention in future studies.

Pretreatment of Sesame Seed (Sesamum indicum L. with Proline and its Effective on Seed Germination and Plant Physiological Defense Systems under Different Temperature Regimes

Directory of Open Access Journals (Sweden)

Nasibeh Tavakoli

2016-06-01

Full Text Available To study the effects of proline and temperature on the rates of antioxidant enzymes and germination index, a factorial laboratory experiment based on completely randomized design was conducted with three replications at the Mohaghegh Ardabili University in 2014. Treatments cinsisted of three levels of proline (0, 5 and 10 mM and different temperature regimes (15, 25 and 35°C. Results showed that proline significantly increased germination index, rates of antioxidant enzymes, proline, protein and mobility of food reserves. Exogenous application of proline increased assimilates in the seedlings. However, proline synthesis was decreased at temrature regimes of 15 and35°C as compared to 25 °C. Peroxidase enzyme rate at 25°C was lowere than of 15 and 35 °C and addition of proline increased levels of enzymes at these temperature regemes. Application of 10 mM proline at 25 °C showed the highest activity of catalase and polyphenol oxidase rates. However, rates of these enzymes at 15 and 35°C decreased as compared with that of 25°C. The length of radicle increased at all temperatures regemes and the length of plumule increased by proline, but reduced at temperatures of 15 and 35°C. According to the positive effects of proline on food reserves and seed vigor index, speed and rate of germination, proline, protein and antioxidant enzymes contents of seedlings, it seems that pretreatment of seeds with proline is an appropriate method for better seed germination attributs under these temperatures regemes.

Effect of Different Germination Conditions on Antioxidative Properties and Bioactive Compounds of Germinated Brown Rice

Directory of Open Access Journals (Sweden)

You-Tung Lin

2015-01-01

Full Text Available This study investigates antioxidative activity and bioactive compounds of ungerminated brown rice (UBR and germinated brown rice (GBR. We used two rice cultivars (Oryza sativa L., Taiwan Japonica 9 (TJ-9 and Taichung Indica 10 (TCI-10, as the materials in our experiments. The conditions for inducing germination are soaking time in water 24, 48, or 72 h; temperature 26 or 36°C; incubation in light or darkness; and open or closed vessels, in which the antioxidative activities and bioactive compounds of GBR were determined. We found that, in order to maximize antioxidative activity and bioactive compounds, germination should be under higher temperature (36°C, long soaking time (72 h, darkness, and closed vessel. GBR contains much higher levels of antioxidative activity and bioactive compounds than ungerminated brown rice (UBR. We found a strong correlation between antioxidative activities (DPPH radical scavenging ability, reducing power, and Trolox equivalent antioxidant capacity and bioactive compounds (γ-oryzanols, tocopherol, and tocotrienol. Higher temperature (36°C is also conducive to the production of GABA in GBR. These results are considered very useful research references for the development of future functional foods and additives.

The site effect on germinability of mugwort (Artemisia vulgaris L. achenes

Directory of Open Access Journals (Sweden)

Jan Winkler

2005-01-01

Full Text Available Mugwort (Artemisia vulgaris L. extremely spreads on uncultivated agricultural land and expands to arable land. Three sites were chosen in the local area of Uherské Hradiště: field (arable land, balk (adjacent to arable land and rubble heap (distant from arable land. At each site, 50 plants were selected from which mature achenes were collected in 2002 and 2003. The achenes germinated in a laboratory at a room temperature and were subjected to various germination conditions. A part of them was exposed to the temperature of – 20 °C in a freezer, the other part was stored at a room temperature. The germination was carried out either on filter paper in Petri dishes or in 30 mm layer of siliceous sand. One part of the achenes germinated in daylight, the other part in Petri dishes in the dark. The achenes cultivated in siliceous sand were covered with a 5 mm layer of the sand. The results were statistically assessed using Unistat software, analysis of variance and methods of least significant differences (LSD. Total average germinability of mugwort achenes was 67,7 %. The differences in germinability of frozen (66,7 % and non-frozen (72,6 % achenes were not statistically significant. Germinability of the achenes that matured in 2003 (69,9 % was highly significantly higher than that of the achenes matured in 2002 (65,4 %. The achenes germinated highly significantly more (77,9 % in daylight as compared with those germinated in the dark (57,4 %. Germinability of the achenes that germinated in siliceous sand was highly significantly higher (70,7 % than of those that germinated in Petri dishes (64,7 %. Germinability of the achenes matured in the field (64,1 % was significantly lower in comparison with the germinability of the achenes from a balk (69,7 % and rubble heap (69,2 %. The results of germinability of the achenes that matured in a rubble heap and balk did not significantly differ.

Karrikin-KAI2 signalling provides Arabidopsis seeds with tolerance to abiotic stress and inhibits germination under conditions unfavourable to seedling establishment.

Science.gov (United States)

Wang, Lu; Waters, Mark T; Smith, Steven M

2018-05-04

The control of seed germination in response to environmental conditions is important for plant success. We investigated the role of the karrikin receptor KARRIKIN INSENSITIVE2 (KAI2) in the response of Arabidopsis seeds to osmotic stress, salinity and high temperature. Germination of the kai2 mutant was examined in response to NaCl, mannitol and elevated temperature. The effect of karrikin on germination of wild-type seeds, hypocotyl elongation and the expression of karrikin-responsive genes was also examined in response to such stresses. The kai2 seeds germinated less readily than wild-type seeds and germination was more sensitive to inhibition by abiotic stress. Karrikin-induced KAI2 signalling stimulated germination of wild-type seeds under favourable conditions, but, surprisingly, inhibited germination in the presence of osmolytes or at elevated temperature. By contrast, GA stimulated germination of wild-type seeds and mutants under all conditions. Karrikin induced expression of DLK2 and KUF1 genes and inhibited hypocotyl elongation independently of osmotic stress. Under mild osmotic stress, karrikin enhanced expression of DREB2A, WRKY33 and ERF5 genes, but not ABA signalling genes. Thus, the karrikin-KAI2 signalling system can protect against abiotic stress, first by providing stress tolerance, and second by inhibiting germination under conditions unfavourable to seedling establishment. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Morphology, ecophysiology and germination of seeds of the Neotropical tree Alibertia patinoi (Rubiaceae

Directory of Open Access Journals (Sweden)

Diego Fernando Escobar Escobar

2013-06-01

Full Text Available Alibertia patinoi (Rubiaceae. Alibertia patinoi (Rubiaceae is of economic and cultural importance for communities in the Colombian Pacific and Amazon regions, where it is cultivated and mature fruits are highly appreciated and consumed. Since there is a lack of knowledge of the seed physiology of this species, we describe here the germination behavior and morphometry of seeds of Alibertia patinoi, and relate them to its habitat. Fruits were collected from a mixed food crop and a commercial plantation in Guaimía village, Buenaventura, Colombia, a tropical rain forest area. We measured length, width, thickness, mass (n=1 400, and moisture content of seeds (n=252. Primary dormancy tests were conducted (n=200, followed by imbibition (n=252 and germination dynamics, under different conditions of light and temperature specific to understory and forest clearings (n=300 seeds. Finally, seed storage behavior was established (n=100 seeds. We observed that size and mass of seeds had a narrow range of values that did not differ within or among fruits and that the species did not exhibit primary dormancy. The seeds are recalcitrant, and recently harvested seeds exhibited higher seed moisture content (ca. 44% and continuous metabolism. The seed germination percentage was observed to be higher under the specific dense canopy forest light and temperature conditions; furthermore, neither enriched far-red light nor darkness conditions inhibited germination. We concluded that rapid germination could be the establishment strategy of this species. Also, the physiological traits (i.e., rapid germination rate, low germination requirements, absence of primary dormancy, and recalcitrant behavior and seed size and mass, suggest that A. patinoi is adapted to conditions of mature tropical rain forests.

[Plant biomorphology and seed germination of pioneer species of the Kamchatka volcanoes].

Science.gov (United States)

Voronkova, N M; Kholina, A B; Verkholat, V P

2008-01-01

Biomorphology, quantitative characters and seed germination of 17 pioneer plant species friable materials of volcanic eruptions (Kamchatka Peninsula) were studied. Adaptive trends in survival stress conditions are discussed. To evaluate a possibility of the cryogenic seed storage, their response to ultra low temperatures (-196 degrees C) was determine.

Size effects in olivine control strength in low-temperature plasticity regime

Science.gov (United States)

Kumamoto, K. M.; Thom, C.; Wallis, D.; Hansen, L. N.; Armstrong, D. E. J.; Goldsby, D. L.; Warren, J. M.; Wilkinson, A. J.

2017-12-01

The strength of the lithospheric mantle during deformation by low-temperature plasticity controls a range of geological phenomena, including lithospheric-scale strain localization, the evolution of friction on deep seismogenic faults, and the flexure of tectonic plates. However, constraints on the strength of olivine in this deformation regime are difficult to obtain from conventional rock-deformation experiments, and previous results vary considerably. We demonstrate via nanoindentation that the strength of olivine in the low-temperature plasticity regime is dependent on the length-scale of the test, with experiments on smaller volumes of material exhibiting larger yield stresses. This "size effect" has previously been explained in engineering materials as a result of the role of strain gradients and associated geometrically necessary dislocations in modifying plastic behavior. The Hall-Petch effect, in which a material with a small grain size exhibits a higher strength than one with a large grain size, is thought to arise from the same mechanism. The presence of a size effect resolves discrepancies among previous experimental measurements of olivine, which were either conducted using indentation methods or were conducted on polycrystalline samples with small grain sizes. An analysis of different low-temperature plasticity flow laws extrapolated to room temperature reveals a power-law relationship between length-scale (grain size for polycrystalline deformation and contact radius for indentation tests) and yield strength. This suggests that data from samples with large inherent length scales best represent the plastic strength of the coarse-grained lithospheric mantle. Additionally, the plastic deformation of nanometer- to micrometer-sized asperities on fault surfaces may control the evolution of fault roughness due to their size-dependent strength.

Experiments on the use of some chloronitrobenzene and organic mercury compounds for the control of low-temperature parasitic fungi on winter cereals

Directory of Open Access Journals (Sweden)

E. A. Jamalainen

1958-01-01

were 75 and 212.5 g per hectare. The amount of active ingredient in the two PMS preparations was 235 and 470 g per hectare, the corresponding amounts of Hg were 110.5 and 221 g per hectare. In the experiment on seed dressing with winter rye in 1955—56 it was ascertained that in addition to the organic mercury preparations also the thiram preparation was effective against Fusarium mould. In seed dressing experiments in Finland considerable increases in yield especially of winter rye have been obtained by using organic mercury compounds when the seed has been normally germinating and not infested by mould. This shows that the small amount of mercury that accompanies the seed into the soil is effective in controlling the low-temperature fungi during the winter.

Effect of gamma rays doses on pollen germination, polysiphony and pollen tube elongation in Pinus patula Schiede et Deppe

International Nuclear Information System (INIS)

Katiyar, S.R.; Chauhan, Y.S.

1987-01-01

The present study aimed to study the effects of gamma radiation ( 60 Co) on pollen germination and pollen tube elongation in Pinus patula. Pollen germination and pollen tube elongation are stimulated by low doses of radiation. Although higher doses of radiation inhibit the germination of pollen, pollen tube elongation remains unaffected. Thus in Pinus patula pollen tube elongation is less radiosensitive than pollen germination. Compared to control pollen, irradiated pollen produced more number of long pollen tubes. Therefore pollen tube size can be improved using low doses of radiation. (author). 15 refs., 5 figs., 2 tables

Effect of mutagens on seed germination in chilli (Capsicum annuum L.)

International Nuclear Information System (INIS)

Dhamayanthi, K.P.M.; Reddy, V.R.K.

2002-01-01

Seeds of chilli variety CO-2 (Coimbatore-2) were irradiated with gamma rays ranging from 10 kR to 35 kR at an interval of 5 kR and the effect on seed germination, seedling survival, percent lethality and seedling injury were studied. Lower doses were stimulative, while higher doses had inhibitory effect on seed germination and seedling survival. The highest percentage of seed germination (37.5) and seedling survival (31.3) was recorded at 10 kR as compared to 28 percent of germination and 3.3 percent seedling survival in control. Percent lethality (9.6%) and seedling injury (6.5%) were comparatively low than the lethality percentage and seedling injury of the higher dose treatments. In chemical mutagen treatments, the maximum seed germination (54.5%) and seedling survival (51.2%), seedling lethality (0.97%) and seedling injury (1.37%) were obtained in the treated seeds of EMS at 0.5% concentration followed by 39.5% seed germination and 30.0% seedling survival, seedling lethality (3.8%) and seedling injury (3.06%) of MMS. The stimulative effect of seed germination is more in chemical mutagens than the physical mutagen. There was a proportionate decrease in germination percentage and seedling survival with an increase in dose/concentration of both the chemicals. (author)

GERMINATION TEST IN SEEDS OF MELOTHRIA CAMPESTRIS (NAUDIN H. SCHAEF. & S.S. RENNER

Directory of Open Access Journals (Sweden)

ANA CARINA DA SILVA CÂNDIDO

2016-01-01

Full Text Available The Cerrado occupies 25% of the Brazilian territory and is the second largest biome in South America, second only to the Amazon Rainforest. Hence, studies on the native species of the Cerrado are important for implementing conservation strategies. In this context, knowledge of the requirements and conditions for germination of seeds of these native species is essential. The Cerrado watermelon ( Melothria campestris (Naudin H. Schaef. & S.S. Renner is a plant that is not cultivated, but has been used in revegetation projects in the countryside of the Cerrado because its fruits are fed upon by fauna in times of food shortage. The purpose of this study was to determine the most appropriate methodology for the germination of the Cerrado watermelon, by identifying the best - suited substrate, the optimal temperature, and the corresponding time taken for germination . The treatments consisted of four substrates: in a paper roll, on paper, in sand, and on sand; and four temperatures: 20, 25, and 30 °C (maintained constant, and a fourth temperature treatment that alternated 20 - 30 °C. The effect of the substrates and temperatures on seed performance was evaluated using the germination test, speed index, and average time for germination. The experimental design was fully randomized, with treatments distributed in a 4 × 4 (substrates × temperatures factorial scheme, with four replications. Our results show that the temperature of 20 °C had a negative influence on germination in all substrates. Further, we found that the germination of the Cerrado watermelon seeds was best in a paper roll or on sand substrate, maintained at a constant temperature of 30 °C, or when temperature was alternated 20 - 30 °C, and the time required for germination stabilization was 30 days.

GERMINATOR: a software package for high-throughput scoring and curve fitting of Arabidopsis seed germination.

Science.gov (United States)

Joosen, Ronny V L; Kodde, Jan; Willems, Leo A J; Ligterink, Wilco; van der Plas, Linus H W; Hilhorst, Henk W M

2010-04-01

Over the past few decades seed physiology research has contributed to many important scientific discoveries and has provided valuable tools for the production of high quality seeds. An important instrument for this type of research is the accurate quantification of germination; however gathering cumulative germination data is a very laborious task that is often prohibitive to the execution of large experiments. In this paper we present the germinator package: a simple, highly cost-efficient and flexible procedure for high-throughput automatic scoring and evaluation of germination that can be implemented without the use of complex robotics. The germinator package contains three modules: (i) design of experimental setup with various options to replicate and randomize samples; (ii) automatic scoring of germination based on the color contrast between the protruding radicle and seed coat on a single image; and (iii) curve fitting of cumulative germination data and the extraction, recap and visualization of the various germination parameters. The curve-fitting module enables analysis of general cumulative germination data and can be used for all plant species. We show that the automatic scoring system works for Arabidopsis thaliana and Brassica spp. seeds, but is likely to be applicable to other species, as well. In this paper we show the accuracy, reproducibility and flexibility of the germinator package. We have successfully applied it to evaluate natural variation for salt tolerance in a large population of recombinant inbred lines and were able to identify several quantitative trait loci for salt tolerance. Germinator is a low-cost package that allows the monitoring of several thousands of germination tests, several times a day by a single person.

[Study on germination characteristics of Disporum cantoniense].

Science.gov (United States)

Huang, Nan; Wang, Hua-Lei; Zhao, Zhi; Liu, Hong-Chang; Luo, Chun-Li; Li, Jin-Ling; Luo, Fu-Lai; Huang, Ming-Jin

2012-11-01

To study the seed germination characteristic and optimal germination condition of wild Disporum cantoniense. Used wild Disporum cantoniense seed as the test materials, the rate of water absorption of the seed was determined. The germination rates under different conditions, along a temperature gradient (15, 20, 25 and 30 degres C), in light or dark, on top or between wet filter papers, and keeping or removing the seed coat, were determined respectively using petri dish method. At the same time germination trends were observed. The thousand seed weight was 33.24 g, and the seed water-absorbing reached saturation pot after soaking for 30 h. Higher germination rates were respectively recorded at 25 degrees C, between filter papers, and in dark after 24 h soaking in the pretreatment solution. The optimal condition for the germination of the seed of wild Disporum cantoniense is as follow: keeping testa, seed soaking for 24 h in seed germination agent and being incubated between wet filter papers in dark at 25 degrees C.

Germinated Pigeon Pea (Cajanus cajan): a novel diet for lowering oxidative stress and hyperglycemia.

Science.gov (United States)

Uchegbu, Nneka N; Ishiwu, Charles N

2016-09-01

This work studied the antioxidant activity of extract of germinated pigeon pea (Cajanus cajan) in alloxan-induced diabetic rats. Germination was carried out in a dark chamber under room temperature (28°C). The total phenolic, 1,1,diphenyl-2-picrylhy-drazyl free radical (DPPH) scavenging, the inhibition of α-amylase and α-glucosidase were done in vitro and blood glucose levels of the animal were investigated. Lipid peroxidation (LPO) and reduced glutathione (GSH) were analyzed spectrophotometrically. The total phenolic and DPPH scavenging activity increased by 30% and 63%, respectively, after germinating pigeon pea. Also after germination there was an increase in the inhibitory potential of pigeon pea extract against α-glucosidase compared with the nongerminated pigeon pea extract. There was a significant increase (P pigeon pea extract gave rise to a reduced fasting blood glucose level in diabetic rats. On administration of germinated pigeon pea extract, LPO reduced drastically but there was an increase in the level of GSH. This study concluded that intake of germinated pigeon pea is a good dietary supplement for controlling hyperglycemia and LPO.

Oxygen dependency of germinating Brassica seeds

Science.gov (United States)

Park, Myoung Ryoul; Hasenstein, Karl H.

2016-02-01

Establishing plants in space, Moon or Mars requires adaptation to altered conditions, including reduced pressure and composition of atmospheres. To determine the oxygen requirements for seed germination, we imbibed Brassica rapa seeds under varying oxygen concentrations and profiled the transcription patterns of genes related to early metabolism such as starch degradation, glycolysis, and fermentation. We also analyzed the activity of lactate dehydrogenase (LDH) and alcohol dehydrogenase (ADH), and measured starch degradation. Partial oxygen pressure (pO2) greater than 10% resulted in normal germination (i.e., protrusion of radicle about 18 hours after imbibition) but lower pO2 delayed and reduced germination. Imbibition in an oxygen-free atmosphere for three days resulted in no germination but subsequent transfer to air initiated germination in 75% of the seeds and the root growth rate was transiently greater than in roots germinated under ambient pO2. In hypoxic seeds soluble sugars degraded faster but the content of starch after 24 h was higher than at ambient oxygen. Transcription of genes related to starch degradation, α-amylase (AMY) and Sucrose Synthase (SUS), was higher under ambient O2 than under hypoxia. Glycolysis and fermentation pathway-related genes, glucose phosphate isomerase (GPI), 6-phosphofructokinase (PFK), fructose 1,6-bisphosphate aldolase (ALD), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), pyruvate decarboxylase (PDC), LDH, and ADH, were induced by low pO2. The activity of LDH and ADH was the highest in anoxic seeds. Germination under low O2 conditions initiated ethanolic fermentation. Therefore, sufficient oxygen availability is important for germination before photosynthesis provides necessary oxygen and the determination of an oxygen carrying capacity is important for uniform growth in space conditions.

Germination and elongation of flax in microgravity

Science.gov (United States)

Levine, Howard G.; Anderson, Ken; Boody, April; Cox, Dave; Kuznetsov, Oleg A.; Hasenstein, Karl H.

2003-05-01

This experiment was conducted as part of a risk mitigation payload aboard the Space Shuttle Atlantis on STS-101. The objectives were to test a newly developed water delivery system, and to determine the optimal combination of water volume and substrate for the imbibition and germination of flax ( Linum usitatissimum) seeds in space. Two different combinations of germination paper were tested for their ability to absorb, distribute, and retain water in microgravity. A single layer of thick germination paper was compared with one layer of thin germination paper under a layer of thick paper. Paper strips were cut to fit snugly into seed cassettes, and seeds were glued to them with the micropyle ends pointing outward. Water was delivered in small increments that traveled through the paper via capillary action. Three water delivery volumes were tested, with the largest (480 μL) outperforming the 400 μL, and 320 μL volumes for percent germination (90.6%) and root growth (mean = 4.1 mm) during the 34-hour spaceflight experiment. The ground control experiment yielded similar results, but with lower rates of germination (84.4%) and shorter root lengths (mean = 2.8 mm). It is not clear if the roots emerged more quickly in microgravity and/or grew faster than the ground controls. The single layer of thick germination paper generally exhibited better overall growth than the two layered option. Significant seed position effects were observed in both the flight and ground control experiments. Overall, the design of the water delivery system, seed cassettes and the germination paper strip concept was validated as an effective method for promoting seed germination and root growth under microgravity conditions.

Germination of Ocotea pulchella (Nees) Mez (Lauraceae) seeds in laboratory and natural restinga environment conditions.

Science.gov (United States)

Pires, L A; Cardoso, V J M; Joly, C A; Rodrigues, R R

2009-08-01

The germination response of Ocotea pulchella (Nees) Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 degrees C, the minimum or base temperature estimated was 11 degrees C and the maximum ranged between 33 and 42 degrees C. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor.

Seed germination in Miconia theaezans (Bonpl. Cogniaux (Melastomataceae

Directory of Open Access Journals (Sweden)

Simone Godoi

2007-07-01

Full Text Available The effects of light and temperature were studied on the seeds of Miconia theazeans by isothermic and alternating temperature incubations. The optimum temperature for seed germination was determined by final percentage and germination rates as located in the range of 27.5 to 30 °C and by germination kinetics at the range of 19.5 to 30 °C. The germination was dependent on diffusion processes. The minimum and maximum temperatures were 12.5-15°C and 32.5-35°C, respectively. The seeds showed strong light dependence for germination with the necessity of daily 4-6 h white light irradiation for the maximum induction of germination. However, under 30-20 °C alternating temperatures, daily 2 hours white light was enough to induce germination and attained maximum under 4 h photoperiod. The results indicated that M. theazeans presented characteristics of early successional species.O efeito da luz e da temperatura na germinação de sementes de Miconia theazeans foi analisado através de incubações isotérmicas e de alternâncias de temperaturas. Através das porcentagens finais e velocidade de germinação concluímos que a temperatura ótima de germinação localizaram-se entre 27,5 e 30 °C e pela cinética de germinação verificamos que entre 19,5 e 30 °C a germinação é dependente de processos de difusão. As temperaturas mínima e máxima foram de 12,5-15 °C e 32,5-35 °C, respectivamente. As sementes apresentaram forte dependência da presença de luz branca para a indução da germinação com a necessidade de 4-6 horas de luz diária para a máxima indução do processo. Entretanto, com a alternância de temperaturas de 30 e 20 °C, fotoperíodo de 2 horas foi suficiente para a indução da germinação sendo o máximo de indução obtida a partir de 4 horas diárias. Estes resultados indicam que Miconia theazeans é uma espécie importante que coloniza clareiras e áreas perturbadas em uma floresta natural.

COMPARATIVE GERMINATION RESPONSES OF COWPEA AND ...

African Journals Online (AJOL)

iya beji

inadequate soil moisture (25%) in both cowpea and maize with greater effect on ... Of all factors controlling productivity, seed germination and vigour are pre- .... depth and date of first irrigation on seed cane germination of two commercial.

Germination of Acacia harpophylla (Brigalow seeds in relation to soil water potential: implications for rehabilitation of a threatened ecosystem

Directory of Open Access Journals (Sweden)

Sven Arnold

2014-02-01

Full Text Available Initial soil water conditions play a critical role when seeding is the primary approach to revegetate post-mining areas. In some semi-arid climates, such as the Brigalow Belt Bioregion in eastern Australia, extensive areas are affected by open-cut mining. Together with erratic rainfall patterns and clayey soils, the Brigalow Belt denotes a unique biome which is representative of other water-limited ecosystems worldwide. Apart from other environmental stressors, germination is governed by the water potential of the surrounding soil material. While previous studies have confirmed the high tolerance of Brigalow (Acacia harpophylla seeds to a broad range of temperature and salinity, the question of how soil water potential triggers seed germination remains. In this study, we used three replicates of 50 seeds of Brigalow to investigate germination in relation to water potential as an environmental stressor. Solutions of Polyethylene Glycol (PEG 6000 were applied to expose seeds to nine osmotic water potentials ranging from soil water saturation (0 MPa and field capacity (−.01 to −.03 MPa to the permanent wilting point (−1.5 MPa. We measured germinability (number of germinated seeds relative to total number of seeds per lot and mean germination time (mean time required for maximum germination of a seed lot to quantify germination. Based on the empirical data of the germination we estimated the parameters of the hydrotime model which simulates timing and success of seed emergence. Our findings indicate that Brigalow seeds are remarkably tolerant to water stress, with germination being observed at a water potential as low as −1.5 MPa. Likewise, the average base water potential of a seed population (hydrotime model was very low and ranged between −1.533 and −1.451 MPa. In general, Brigalow seeds germinate opportunistically over a broad range of abiotic conditions related to temperature, salinity, and water availability. Direct seeding and

The Responses of Mulch Closure on the Germination of Mindi (Melia azedarach Linn.

Directory of Open Access Journals (Sweden)

Nurmawati Siregar

2017-08-01

Full Text Available One of the factors that determine the successful of the development of mindi is the availability of seedling. The seedlings can be propagated generatively by using seeds, however there is a problem related to the hardness of the testa that make it difficult to germinate, so it needs environment condition treatments to get optimal germination, one of this is mulching. The use mulch possibly get the improvement of temperature, humidity, infiltration and evapotranspiration. The study is aimed to determine the effect of mulch and to find out the best mulch type on the germination of mindi (Melia azedarach Linn. seed. Randomized completely design was employed that arranged factorially, consisted of (A mulch types factor and mulch thicknesses factor (B. There were 5 (five types of mulch treatment i.e rice straws, transparent plastics, dark plastics, zeolite and without mulch. The thicknesses of mulch consisted of one layer and two layers of mulch. Germination capacity, germination speed and growth simultaneously were observed. The results showed, mulching effect on germination mindi the best type of mulch is black or transparent plastic mulch while the thickness of the mulch does not affect the germination. Mindi seed capable of germination in the dark and light conditions on the conditions of temperature and humidity high temperatures.

Control system for Fermilab's low temperature upgrade

International Nuclear Information System (INIS)

Norris, B.L.

1996-09-01

Fermilab recently upgraded the Tevatron Cryogenic Systems to allow for lower temperature operation. This Lower Temperature Upgrade grew out of a desire to increase the Colliding Beam Physics energy from 900 GeV to 1000 GeV. A key element in achieving this goal is the new cryogenic control system designed at Fermilab and installed in 24 satellite refrigerators and 8 compressor buildings. The cryogenic improvements and addition hardware like cold compressors exceeded the capability of the original distributed controls package. The new distributed controls package uses a Multibus II platform and Intel's 80386 microprocessor. Token Ring is used as the link to the systems 6 primary crate locations with Arcnet used as the connection to the systems numerous I/O crates. I/0 capabilities are double the capabilities of the original system. Software has also been upgraded with the introduction of more flexible control loop strategies and Finite State Machines used for automatic sequential control, like quench recovery or cold compressor pump down

Germination and elongation of flax in microgravity

Science.gov (United States)

Levine, Howard G.; Anderson, Ken; Boody, April; Cox, Dave; Kuznetsov, Oleg A.; Hasenstein, Karl H.

2003-01-01

This experiment was conducted as part of a risk mitigation payload aboard the Space Shuttle Atlantis on STS-101. The objectives were to test a newly developed water delivery system, and to determine the optimal combination of water volume and substrate for the imbibition and germination of flax (Linum usitatissimum) seeds in space. Two different combinations of germination paper were tested for their ability to absorb, distribute, and retain water in microgravity. A single layer of thick germination paper was compared with one layer of thin germination paper under a layer of thick paper. Paper strips were cut to fit snugly into seed cassettes, and seeds were glued to them with the micropyle ends pointing outward. Water was delivered in small increments that traveled through the paper via capillary action. Three water delivery volumes were tested, with the largest (480 microliters) outperforming the 400 microliters and 320 microliters volumes for percent germination (90.6%) and root growth (mean=4.1 mm) during the 34-hour spaceflight experiment. The ground control experiment yielded similar results, but with lower rates of germination (84.4%) and shorter root lengths (mean=2.8 mm). It is not clear if the roots emerged more quickly in microgravity and/or grew faster than the ground controls. The single layer of thick germination paper generally exhibited better overall growth than the two layered option. Significant seed position effects were observed in both the flight and ground control experiments. Overall, the design of the water delivery system, seed cassettes and the germination paper strip concept was validated as an effective method for promoting seed germination and root growth under microgravity conditions. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

Germination of Ocotea pulchella (Nees Mez (Lauraceae seeds in laboratory and natural restinga environment conditions

Directory of Open Access Journals (Sweden)

LA. Pires

Full Text Available The germination response of Ocotea pulchella (Nees Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 ºC, the minimum or base temperature estimated was 11 ºC and the maximum ranged between 33 and 42 ºC. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor.

Chickpea seeds germination rational parameters optimization

Science.gov (United States)

Safonova, Yu A.; Ivliev, M. N.; Lemeshkin, A. V.

2018-05-01

The paper presents the influence of chickpea seeds bioactivation parameters on their enzymatic activity experimental results. Optimal bioactivation process modes were obtained by regression-factor analysis: process temperature - 13.6 °C, process duration - 71.5 h. It was found that in the germination process, the proteolytic, amylolytic and lipolytic enzymes activity increased, and the urease enzyme activity is reduced. The dependences of enzyme activity on chickpea seeds germination conditions were obtained by mathematical processing of experimental data. The calculated data are in good agreement with the experimental ones. This confirms the optimization efficiency based on experiments mathematical planning in order to determine the enzymatic activity of chickpea seeds germination optimal parameters of bioactivated seeds.

Temperature and Water Effects on the Viability of Alginate-Formulated Oospores of Pythrium Oligandrum

Directory of Open Access Journals (Sweden)

A. K. Al-Rawahi

1998-06-01

Full Text Available The low germination rates of oospores hinder the use of Pythium oligandrum as a biocontrol agent of soilborne plant pathogens. To improve the reliability of oospore-inoculum of P. oligandrum for the biological control of root diseases, oospores were formulated in calcium alginate pellets (oospore-pellets. Oospore-pellets of five isolates of P. oligandrum stored at 4°C under dry conditions remained viable (more or equal than 99% germination for each time interval over 12 months regardless of the culture medium used to produce the oospores. In contrast, oospore-pellets stored at 25°C under the same conditions maintained their viability for 3 months but declined to 50%, viability in the following 9 months. Germination of oospore-pellets was at the highest (98% at solute potentials (y8 higher than -l.33 MPa or relative humidities (RH higher than 97% at 25° and 33°C. Germination declined sharply as (y8, decreased from -1.33 to -2.59 MPa and RH decreased from 97 to 94% with no germination occurring at -3.59 MPa and 92% RH. Only 60% germination was found at 16°C in the top range of y, and RH, and germination declined sharply as y, and RH were decreased, with no germination occurring at - l .33 MPa and 95% RH. Mycelial growth exhibited similar ranges of tolerance under the same moisture conditions and temperatures. High degrees of survival during storage accompanied by high percentages of germination under relatively dry conditions suggest that the oospore-pellet inoculum of P. oligandrum can be used for the control of pathogens in soil or a potting mix at high temperatures during a warm season or under greenhouse conditions.

Metabolism and the triggering of germination of Bacillus megaterium

International Nuclear Information System (INIS)

Scott, I.R.; Ellar, D.J.

1978-01-01

L-[2,3- 3 H]Alanine was used to probe for metabolism of alanine during triggering of germination of spores of Bacillus megaterium KM. No detectable incorporation of label into any compound, including water, was found, indicating that any metabolism involving the alanine germinant must be at a very low rate and also that alanine racemase is absent from spores of this strain. Spores were germinated in 3 H 2 0 to find if any of the many metabolic reactions causing irreversible incorporation of 3 H into reaction products took place during triggering og germination. No incorporation was detected until 2-3 min after addition of germinants. It is therefore concluded that a wide variety of metabolic routes, including glycolysis, the tricarboxylic acid cycle, the pentose phosphate pathway and amino acid metabolism are either not involved in the reactions causing the triggering of germination or operate at an extremely low rate during this process. (author)

Spore Heat Activation Requirements and Germination Responses Correlate with Sequences of Germinant Receptors and with the Presence of a Specific spoVA2mob Operon in Foodborne Strains of Bacillus subtilis.

Science.gov (United States)

Krawczyk, Antonina O; de Jong, Anne; Omony, Jimmy; Holsappel, Siger; Wells-Bennik, Marjon H J; Kuipers, Oscar P; Eijlander, Robyn T

2017-04-01

Spore heat resistance, germination, and outgrowth are problematic bacterial properties compromising food safety and quality. Large interstrain variation in these properties makes prediction and control of spore behavior challenging. High-level heat resistance and slow germination of spores of some natural Bacillus subtilis isolates, encountered in foods, have been attributed to the occurrence of the spoVA 2mob operon carried on the Tn 1546 transposon. In this study, we further investigate the correlation between the presence of this operon in high-level-heat-resistant spores and their germination efficiencies before and after exposure to various sublethal heat treatments (heat activation, or HA), which are known to significantly improve spore responses to nutrient germinants. We show that high-level-heat-resistant spores harboring spoVA 2mob required higher HA temperatures for efficient germination than spores lacking spoVA 2mob The optimal spore HA requirements additionally depended on the nutrients used to trigger germination, l-alanine (l-Ala), or a mixture of l-asparagine, d-glucose, d-fructose, and K + (AGFK). The distinct HA requirements of these two spore germination pathways are likely related to differences in properties of specific germinant receptors. Moreover, spores that germinated inefficiently in AGFK contained specific changes in sequences of the GerB and GerK germinant receptors, which are involved in this germination response. In contrast, no relation was found between transcription levels of main germination genes and spore germination phenotypes. The findings presented in this study have great implications for practices in the food industry, where heat treatments are commonly used to inactivate pathogenic and spoilage microbes, including bacterial spore formers. IMPORTANCE This study describes a strong variation in spore germination capacities and requirements for a heat activation treatment, i.e., an exposure to sublethal heat that increases

Portable Diagnostics and Rapid Germination

Energy Technology Data Exchange (ETDEWEB)

Dunn, Zachary Spencer [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2016-12-01

In the Bioenergy and Defense Department of Sandia National Laboratories, characterization of the BaDx (Bacillus anthracis diagnostic cartridge) was performed and rapid germination chemistry was investigated. BaDx was tested with complex sample matrixes inoculated with Bacillus anthracis, and the trials proved that BaDx will detect Bacillus anthracis in a variety of the medium, such as dirt, serum, blood, milk, and horse fluids. The dimensions of the device were altered to accommodate an E. coli or Listeria lateral flow immunoassay, and using a laser printer, BaDx devices were manufactured to identify E. coli and Listeria. Initial testing with E. coli versions of BaDx indicate that the device will be viable as a portable diagnostic cartridge. The device would be more effective with faster bacteria germination; hence studies were performed the use of rapid germination chemistry. Trials with calcium dipicolinic acid displayed increased cell germination, as shown by control studies using a microplate reader. Upon lyophilization the rapid germination chemistry failed to change growth patterns, indicating that the calcium dipicolinic acid was not solubilized under the conditions tested. Although incompatible with the portable diagnostic device, the experiments proved that the rapid germination chemistry was effective in increasing cell germination.

Pollen characteristics and in vitro pollen germination of Cedrus ...

African Journals Online (AJOL)

PRECIOUS

2009-11-02

Nov 2, 2009 ... This study aims to determine the germination characteristics, pollen tube developments, effects of germination media and temperature and incubation durations of the pollens obtained from the four clones (11342, 11344, 11345 and 11351) of Cedrus libani A. Rich. (Lebanon Cedrus) obtained from clonal.

Germination conditions affect physicochemical properties of germinated brown rice flour.

Science.gov (United States)

Charoenthaikij, Phantipha; Jangchud, Kamolwan; Jangchud, Anuvat; Piyachomkwan, Kuakoon; Tungtrakul, Patcharee; Prinyawiwatkul, Witoon

2009-01-01

Germinated brown rice has been reported to be nutritious due to increased free gamma-aminobutyric acid (GABA). The physicochemical properties of brown rice (BR) and glutinous brown rice (GNBR) after germination as affected by different steeping times (24, 36, 48, and 72 h depending on the rice variety) and pHs of steeping water (3, 5, 7, and as-is) were determined and compared to those of the nongerminated one (control). As the steeping time increased or pH of steeping water decreased, germinated brown rice flours (GBRF) from both BR and GNBR had greater reducing sugar, free GABA and alpha-amylase activity; while the total starch and viscosity were lower than their respective controls. GBRFs from both BR and GNBR prepared after 24-h steeping time at pH 3 contained a high content of free GABA at 32.70 and 30.69 mg/100 g flour, respectively. The peak viscosity of GBRF obtained from both BR and GNBR (7.42 to 228.22 and 4.42 to 58.67 RVU, respectively) was significantly lower than that of their controls (255.46 and 190.17 RVU, respectively). The principal component analysis indicated that the important variables for discriminating among GBRFs, explained by the first 2 components at 89.82% of total explained variance, were the pasting profiles, alpha-amylase activity, and free GABA.

Seed size influence on germination responses to light and temperature of seven pioneer tree species from the Central Amazon

Directory of Open Access Journals (Sweden)

Fabiana F. Aud

2012-09-01

Full Text Available In Amazon secondary forests are dominated by pioneer species that typically produce large amounts of small and dormant seeds that are able to form a persistent soil seed bank. Seed dormancy in this group of species is overcome by environmental conditions found in open areas, such as high irradiation or alternating temperatures. Nevertheless, a variety of germination responses to environmental factors is known among pioneers; some of them may germinate in diffuse light or in darkness condition at constant temperature. Seed mass can be considered as one of the factors that promotes this variety. Regarding species with very small seeds, it seems that the trigger for germination is light and for larger seeds temperature alternation may be a more important stimulus. In this study we established a relationship between seed mass and germination response to light and alternating temperature for a group of seven woody pioneer species from the Amazon forest. We found that an increase in seed mass was followed by a decrease in the need for light and an increase in the tolerance to alternating temperatures. Understanding germination strategies may contribute with the knowledge of species coexistence in high diverse environments and also may assist those involved in forest management and restoration.Na Amazônia as florestas secundárias são dominadas por espécies pioneiras que, normalmente, produzem grandes quantidades de sementes pequenas, dormentes e capazes de formar bancos de sementes no solo. A dormência neste grupo de espécies é superada pelas condições ambientais de áreas abertas, como alta irradiação ou alternância de temperaturas. No entanto, uma variedade de respostas de germinação aos fatores ambientais é conhecida entre as pioneiras; algumas germinam em luz difusa ou no escuro sob temperatura constante. Um dos fatores promotores desta variedade é a massa das sementes. Parece que para as espécies com sementes muito pequenas, o est

Barley germination

DEFF Research Database (Denmark)

Daneri-Castro, Sergio N.; Svensson, Birte; Roberts, Thomas H.

2016-01-01

germination. Lastly, the application of metabolomics to barley grain germination provides essential data on biochemical processes, including insights into the formation of compounds that contribute to malt quality. To maximize the benefits of the 'omics' revolution to the malting industry, there is a need......Germination of barley grain is central to the malting industry and is a valuable model for cereal grain germination. Our current understanding of the complexity of germination at the molecular level is facilitated by access to genomic, transcriptomic, proteomic and metabolomic data. Here we review...... of germination in the context of industrial malting. For transcriptomics, recent advances in sequencing the barley genome allow next-generation sequencing approaches to reveal novel effects of variety and environment on germination. For proteomics, selection of the source tissue(s) and the protein extraction...

Lettuce achene invigoration through osmopriming at supraoptimal temperature

International Nuclear Information System (INIS)

Jahangir, M.M.; Amjad, M.; Iqbal, Q.; Nawaz, A.; Afzal, I.

2009-01-01

The effect of osmopriming on lettuce achene invigoration at supra optimal temperature (35degreeC) was investigated in the present study. Osmopriming of lettuce achene with KNO/sub 3/ (0.25%, 0.5% and 1%), CaCl/sub 2/ (15 mM, 25 mM, 50 mM) and PEG 8000 (0.1 g/ml H/sub 2/O, 0.2 g/ml H/sub 2/O, 0.3g/ml H/sub 2/O) alleviated thermodormancy and improved lettuce achene's vigor. Moreover, priming significantly improved final germination % age, energy of germination, germination index, shoot length, root length, vigor index and reduced mean germination time and time taken to 50% germination, as compared to control, when seeds were subjected to supra-optimal germination environments. It can be concluded that osmopriming can act as effective tool to invigorate lettuce seeds at supra optimal temperature. (author)

In vitro seed germination of economically important edible bamboo Dendrocalamus membranaceus Munro.

Science.gov (United States)

Brar, Jasmine; Anand, Manju; Sood, Anil

2013-01-01

An in vitro propagation protocol using mature seeds of D. membranaceus was successfully established. Scarcity of seeds in bamboos because of their long flowering periods and irregular seed set resulting in low viability and germination potential, motivated us to undertake the present study. The effects of sterilants, light conditions, exogenous application of plant growth regulators and temperature in overcoming germination barriers in ageing seeds of bamboo were studied. It was found that HgCl2 (0.1%) along with bleach (15%) was more effective in raising aseptic cultures. Dark conditions, high temperatures around 30 degrees C and soaking of seeds in GA3 solution (50 ppm) overnight stimulated high percent of seed germination with corresponding increase in shoot length (2.7 +/- 0.7 mm) and number of sprouts (2.1 +/- 0.7) per explants during culture initiation. 6-benzylaminopurine acted synergistically with kinetin to give optimum germination rate of 70 +/- 13.9% as compared to 63.13% when used individually. For prolonged maintenance of cultures, 2% sucrose was found to be suitable for promoting photomixotrophic micropropagation. Following this procedure, about 65% survival of plantlets could be achieved during hardening. Biochemically seeds consume starchy endosperm for emergence of radicle which is taken as a sign of germination as also evident from the present study. Loss of viability and vigour after a year was confirmed by Tetrazolium chloride test. Micropropagation protocol developed here will ensure regeneration of large number of plants in a relatively short time. Conclusively, in vitro propagation protocol developed in D. membranaceus using mature seeds as an explants is reported for the first time.

Improvement of Chia Seeds with Antioxidant Activity, GABA, Essential Amino Acids, and Dietary Fiber by Controlled Germination Bioprocess.

Science.gov (United States)

Gómez-Favela, Mario Armando; Gutiérrez-Dorado, Roberto; Cuevas-Rodríguez, Edith Oliva; Canizalez-Román, Vicente Adrián; Del Rosario León-Sicairos, Claudia; Milán-Carrillo, Jorge; Reyes-Moreno, Cuauhtémoc

2017-12-01

Chia (Salvia hispanica L.) plant is native from southern Mexico and northern Guatemala. Their seeds are a rich source of bioactive compounds which protect consumers against chronic diseases. Germination improves functionality of the seeds due to the increase in the bioactive compounds and associated antioxidant activity. The purpose of this study was to obtain functional flour from germinated chia seeds under optimized conditions with increased antioxidant activity, phenolic compounds, GABA, essential amino acids, and dietary fiber with respect to un-germinated chia seeds. The effect of germination temperature and time (GT = 20-35 °C, Gt = 10-300 h) on protein, lipid, and total phenolic contents (PC, LC, TPC, respectively), and antioxidant activity (AoxA) was analyzed by response surface methodology as optimization tool. Chia seeds were germinated inside plastic trays with absorbent paper moisturized with 50 mL of 100 ppm sodium hypochlorite dissolution. The sprouts were dried (50 °C/8 h) and ground to obtain germinated chia flours (GCF). The prediction models developed for PC, LC, TPC, and AoxA showed high coefficients of determination, demonstrating their adequacy to explain the variations in experimental data. The highest values of PC, LC, TPC, and AoxA were obtained at two different optimal conditions (GT = 21 °C/Gt = 157 h; GT = 33 °C/Gt = 126 h). Optimized germinated chia flours (OGCF) had higher PC, TPC, AoxA, GABA, essential amino acids, calculated protein efficiency ratio (C-PER), and total dietary fiber (TDF) than un-germinated chia seed flour. The OGCF could be utilized as a natural source of proteins, dietary fiber, GABA, and antioxidants in the development of new functional beverages and foods.

Germination et croissance initiale de Neocarya macrophylla (Sabine Prance, une espèce oléagineuse du Niger

Directory of Open Access Journals (Sweden)

Dan Guimbo, I.

2011-01-01

Full Text Available Germination and Initial Growth of Neocarya macrophylla (Sabine Prance, a oleaginous Species of Niger. The study conducted in parallel in the real environment, nursery and laboratory to better understand the characteristics of germination and seedling development Neocarya macrophylla, a species of oleaginous Niger. The treatments applied to seed have a waiting time shorter than the untreated seeds. The control has a staggered germination (30 days and shelling of nuts influenced seed germination bundled (16 days. Unprocessed nuts are the best germination rate (89.53%. Soaking nuts during 72 h and 120 h is fatal for germination. The shelf life has significant effects on the germination of walnuts and almonds. The observation shows a germinating seed cryptogeal. The low germination rates nuts without water shows that water is a limiting factor to the spread of this tree species. The seedlings are very sensitive to dampingoff and tolerant enough to transplantation with a survival rate of 79%.

Certification testing at low temperatures

International Nuclear Information System (INIS)

Noss, P.W.; Ammerman, D.J.

2004-01-01

Regulations governing the transport of radioactive materials require that most hypothetical accident condition tests or analyses consider the effects of the environmental temperature that most challenges package performance. For many packages, the most challenging temperature environment is the cold condition (-29 C according to U.S. regulations), primarily because the low temperature causes the highest free drop impact forces due to the higher strength of many energy-absorbing materials at this temperature. If it is decided to perform low temperature testing, it is only necessary that the relevant parts of the package have the required temperature prior to the drop. However, the details of performing a drop at low temperature can have a large influence on testing cost and technical effectiveness. The selection of the test site, the chamber and type of chilling equipment, instrumentation, and even the time of year are all important. Control of seemingly minor details such as the effect on internal pressure, placement of monitoring thermocouples, the thermal time constant of the test article, and icing of equipment are necessary to ensure a successful low temperature test. This paper will discuss these issues and offer suggestions based on recent experience

Lipolytic activity in high temperature germinating Almond seedlings

African Journals Online (AJOL)

bahri

2012-09-20

Sep 20, 2012 ... Felipe A (1981). Germination accelérée d'amandes au moyen de l'acide gibbérellique. Cahier Options Méditerranéennes I:139-140. Hirayama O, Matsuda H (1972). An improved method for determining lipolytic acylhydrolases activity. Agric. Biol. Chem. 36(10):1831-. 1833. Garcia-Olmedo R, Marca-Garcia ...

Oxygen requirement of germinating flax seeds

Science.gov (United States)

Kuznetsov, Oleg A.; Hasenstein, K. H.

2003-05-01

Plant experiments in earth orbit are typically prepared on the ground and germinated in orbit to study gravity effects on the developing seedlings. Germination requires the breakdown of storage compounds, and this metabolism depends upon respiration, making oxygen one of the limiting factors in seed germination. In microgravity lack of run-off of excess water requires careful testing of water dispensation and oxygen availability. In preparation for a shuttle experiment (MICRO on STS-107) we studied germination and growth of flax ( Linum usitatissimum L.) seedlings in the developed hardware (Magnetic Field Chamber, MFC). We tested between four to 32 seeds per chamber (air volume = 14 mL) and after 36 h measured the root length. At 90 μl O 2 per seed (32 seeds/chamber), the germination decreased from 94 to 69%, and the root length was reduced by 20%, compared to 8 seeds per chamber. Based on the percent germination and root length obtained in controlled gas mixtures between 3.6 and 21.6% O 2 we determined the lower limit of reliable germination to be 10 vol. % O 2 at atmospheric pressure. Although the oxygen available in the MFC's can support the intended number of seeds, the data show that seed storage and microgravity-related limitations may reduce germination.

Germination and seedling frost tolerance differ between the native and invasive range in common ragweed.

Science.gov (United States)

Leiblein-Wild, Marion Carmen; Kaviani, Rana; Tackenberg, Oliver

2014-03-01

Germination characteristics and frost tolerance of seedlings are crucial parameters for establishment and invasion success of plants. The characterization of differences between populations in native and invasive ranges may improve our understanding of range expansion and adaptation. Here, we investigated germination characteristics of Ambrosia artemisiifolia L., a successful invader in Europe, under a temperature gradient between 5 and 25 °C. Besides rate and speed of germination we determined optimal, minimal and maximal temperature for germination of ten North American and 17 European populations that were sampled along major latitudinal and longitudinal gradients. We furthermore investigated the frost tolerance of seedlings. Germination rate was highest at 15 °C and germination speed was highest at 25 °C. Germination rate, germination speed, frost tolerance of seedlings, and the temperature niche width for germination were significantly higher and broader, respectively, for European populations. This was partly due to a higher seed mass of these populations. Germination traits lacked evidence for adaptation to climatic variables at the point of origin for both provenances. Instead, in the native range, seedling frost tolerance was positively correlated with the risk of frosts which supports the assumption of local adaptation. The increased frost tolerance of European populations may allow germination earlier in the year which may subsequently lead to higher biomass allocation--due to a longer growing period--and result in higher pollen and seed production. The increase in germination rates, germination speed and seedling frost tolerance might result in a higher fitness of the European populations which may facilitate further successful invasion and enhance the existing public health problems associated with this species.

Using composting for control seed germination of invasive plant (water hyacinth) in Extremadura (Spain)

Science.gov (United States)

Labrador, Juana; Gordillo, Judit; Ruiz, Trinidad; Albano, Eva; Moreno, Marta M.

2016-04-01

The biotransformation of the invasive water hyacinth (Eichhornia crassipes) by composting has been showed as a viable alternative to offset the economic cost of eliminating an invasive plant giving a value to the by-product; however, as result of the propagative plant capacity, it was necessary to check if the composting process could eliminate the germination seed rate. Despite the high temperatures and the biochemical biotransformation processes of the composting components, in the case of seed water hyacinth, with a recovery rate of 100%, damage was observed in some parts of the seed anatomy such as in the outer teguments; however, other parts of the seed coat and the endosperm maintained their integrity. A microscopic analysis revealed that the embryo was noticeable and this was supported by the rate of seed germination observed (3.5 ± 0.96%). The results indicate that the use of water hyacinth for compost production is not completely safe from an environmental perspective. Keywords: Eichhornia crassipes, water hyacinth, invasive plant, seed anatomy, seed germination rate, compost. References: Ruiz T., Martín de Rodrigo E., Lorenzo G., Albano E., Morán R., Sánchez J.M. 2008. The Water Hyacinth, Eichhornia crassipes: an invasive plant in the Guadiana River Basin (Spain). Aquatic Invasions Volume 3, Issue 1:42-53.

Interference of germination time on chemical composition and antioxidant capacity of white sesame (Sesamum Indicum

Directory of Open Access Journals (Sweden)

Luísa Fernandes de Menezes MARES

2017-12-01

Full Text Available Abstract The consumption of white sesame has become a healthy option for those who are concerned about health and wish to reduce oxidative stress. The germination has been used an effective method to increase the nutrients availability and thus provide a better nutritional quality of these seeds. Due to the lack of researches about sesame germination the objective of this study was to evaluate the different times of germination on the chemical composition (moisture, fat, protein and ashes, the antioxidant capacity and the phenolic compounds of white sesame. The germination occurred inside a greenhouse with controlled temperature at 30 °C and the variables were analyzed in the times 0, 24, 36 and 48 hours of germination. The process increased the levels of moisture and reduced the levels of fat, protein and ashes. On the other hand, it also increased the antioxidant capacity by two methods and raised the quantity of total phenolic compounds. Based in the present study and in others similar works, it is possible to affirm that the germination process increase the white sesames’ antioxidant capacity, however further studies are needed to evaluate a better environmental condition of germination and others factors that may affect the composition.

[Effects of illumination and seed-soaking reagent on seed germination of Solanum nigrum].

Science.gov (United States)

Yang, Chuan-Jie; Wei, Shu-He; Zhou, Qi-Xing; Hu, Ya-Hu; Niu, Rong-Cheng

2009-05-01

To explore a rapid seed germination method for hyperaccumulator Solanum nigrum, a germination experiment with different illumination and seed-soaking treatments was conducted in constant temperature box and greenhouse, with filter as burgeon base. Under illumination, the germination rate was about 5 times high of that without illumination (P seed germination of S. nigrum. All test seed-soaking reagents could significantly improve the germination rate of S. nigrum (P seeds treated with H2O2 had the shortest germination time. The germination rate of seeds soaked but without cleaning was 2-3 times as high as that of seeds soaked and cleaned with water.

Influence of diesel fuel on seed germination

International Nuclear Information System (INIS)

Adam, Gillian; Duncan, Harry

2002-01-01

The volatile fraction of diesel fuel played a major role in delaying seed emergence and reducing percentage germination. - The use of plant-based systems to remediate contaminated soils has become an area of intense scientific study in recent years and it is apparent that plants which grow well in contaminated soils need to be identified and screened for use in phytoremediation technologies. This study investigated the effect of diesel fuel on germination of selected plant species. Germination response varied greatly with plant species and was species specific, as members of the same plant family showed differential sensitivity to diesel fuel contamination. Differences were also seen within plant subspecies. At relatively low levels of diesel fuel contamination, delayed seed emergence and reduced percentage germination was observed for the majority of plant species investigated. Results suggest the volatile fraction of diesel fuel played an influential role in delaying seed emergence and reducing percentage germination. In addition, the remaining diesel fuel in the soil added to this inhibitory effect on germination by physically impeding water and oxygen transfer between the seed and the surrounding soil environment, thus hindering the germination response

Phytotoxicity of glyphosate in the germination of and its effect on germinated seedlings

Directory of Open Access Journals (Sweden)

Subinoy Mondal

2017-08-01

Full Text Available The present study evaluated the effects of glyphosate on Pisum sativum germination as well as its effect on the physiology and biochemistry of germinated seedlings. Different physico-chemical biomarkers, viz., chlorophyll, root and shoot length, total protein and soluble sugar, along with sodium and potassium concentration, were investigated in germinated seedlings at different glyphosate concentrations. This study reports the influence of different concentrations of glyphosate on pea seeds and seedlings. Physicochemical biomarkers were significantly changed by glyphosate exposure after 15 days. The germination of seedlings under control conditions (0 mg/L was 100% after 3 days of treatment but at 3 and 4 mg/L glyphosate, germination was reduced to 55 and 40%, respectively. Physiological parameters like root and shoot length decreased monotonically with increasing glyphosate concentration, at 14 days of observation. Average root and shoot length (n=30 in three replicates were reduced to 14.7 and 17.6%, respectively, at 4 mg/L glyphosate. Leaf chlorophyll content also decreased, with a similar trend to root and shoot length, but the protein content initially decreased and then increased with an increase in glyphosate concentration to 3 mg/L. The study suggests that glyphosate reduces the soluble sugar content significantly, by 21.6% (v/v. But internal sodium and potassium tissue concentrations were significantly altered by glyphosate exposure with increasing concentrations of glyphosate. Biochemical and physiological analysis also supports the inhibitory effect of glyphosate on seed germination and biochemical effects on seedlings.

Using In Situ Symbiotic Seed Germination to Restore Over-collected Medicinal Orchids in Southwest China

Directory of Open Access Journals (Sweden)

Shi-Cheng Shao

2017-06-01

Full Text Available Due to increasing demand for medicinal and horticultural uses, the Orchidaceae is in urgent need of innovative and novel propagation techniques that address both market demand and conservation. Traditionally, restoration techniques have been centered on ex situ asymbiotic or symbiotic seed germination techniques that are not cost-effective, have limited genetic potential and often result in low survival rates in the field. Here, we propose a novel in situ advanced restoration-friendly program for the endangered epiphytic orchid species Dendrobium devonianum, in which a series of in situ symbiotic seed germination trials base on conspecific fungal isolates were conducted at two sites in Yunnan Province, China. We found that percentage germination varied among treatments and locations; control treatments (no inoculum did not germinate at both sites. We found that the optimal treatment, having the highest in situ seed germination rate (0.94-1.44% with no significant variation among sites, supported a warm, moist and fixed site that allowed for light penetration. When accounting for seed density, percentage germination was highest (2.78-2.35% at low densities and did not vary among locations for the treatment that supported optimal conditions. Similarly for the same treatment, seed germination ranged from 0.24 to 5.87% among seasons but also did vary among sites. This study reports on the cultivation and restoration of an endangered epiphytic orchid species by in situ symbiotic seed germination and is likely to have broad application to the horticulture and conservation of the Orchidaceae.

Using In Situ Symbiotic Seed Germination to Restore Over-collected Medicinal Orchids in Southwest China.

Science.gov (United States)

Shao, Shi-Cheng; Burgess, Kevin S; Cruse-Sanders, Jennifer M; Liu, Qiang; Fan, Xu-Li; Huang, Hui; Gao, Jiang-Yun

2017-01-01

Due to increasing demand for medicinal and horticultural uses, the Orchidaceae is in urgent need of innovative and novel propagation techniques that address both market demand and conservation. Traditionally, restoration techniques have been centered on ex situ asymbiotic or symbiotic seed germination techniques that are not cost-effective, have limited genetic potential and often result in low survival rates in the field. Here, we propose a novel in situ advanced restoration-friendly program for the endangered epiphytic orchid species Dendrobium devonianum , in which a series of in situ symbiotic seed germination trials base on conspecific fungal isolates were conducted at two sites in Yunnan Province, China. We found that percentage germination varied among treatments and locations; control treatments (no inoculum) did not germinate at both sites. We found that the optimal treatment, having the highest in situ seed germination rate (0.94-1.44%) with no significant variation among sites, supported a warm, moist and fixed site that allowed for light penetration. When accounting for seed density, percentage germination was highest (2.78-2.35%) at low densities and did not vary among locations for the treatment that supported optimal conditions. Similarly for the same treatment, seed germination ranged from 0.24 to 5.87% among seasons but also did vary among sites. This study reports on the cultivation and restoration of an endangered epiphytic orchid species by in situ symbiotic seed germination and is likely to have broad application to the horticulture and conservation of the Orchidaceae.

Oxygen requirement of germinating flax seeds

Science.gov (United States)

Kuznetsov, Oleg A.; Hasenstein, K. H.; Hasentein, K. H. (Principal Investigator)

2003-01-01

Plant experiments in earth orbit are typically prepared on the ground and germinated in orbit to study gravity effects on the developing seedlings. Germination requires the breakdown of storage compounds, and this metabolism depends upon respiration, making oxygen one of the limiting factors in seed germination. In microgravity lack of run-off of excess water requires careful testing of water dispensation and oxygen availability. In preparation for a shuttle experiment (MICRO on STS-107) we studied germination and growth of flax (Linum usitatissimum L.) seedlings in the developed hardware (Magnetic Field Chamber, MFC). We tested between four to 32 seeds per chamber (air volume=14 mL) and after 36 h measured the root length. At 90 microliters O2 per seed (32 seeds/chamber), the germination decreased from 94 to 69%, and the root length was reduced by 20%, compared to 8 seeds per chamber. Based on the percent germination and root length obtained in controlled gas mixtures between 3.6 and 21.6% O2 we determined the lower limit of reliable germination to be 10 vol. % O2 at atmospheric pressure. Although the oxygen available in the MFC's can support the intended number of seeds, the data show that seed storage and microgravity-related limitations may reduce germination. c2003 Published by Elsevier Ltd on behalf of COSPAR.

Low temperature carrier transport properties in isotopically controlled germanium

Energy Technology Data Exchange (ETDEWEB)

Itoh, Kohei [Univ. of California, Berkeley, CA (United States)

1994-12-01

Investigations of electronic and optical properties of semiconductors often require specimens with extremely homogeneous dopant distributions and precisely controlled net-carrier concentrations and compensation ratios. The previous difficulties in fabricating such samples are overcome as reported in this thesis by growing high-purity Ge single crystals of controlled ⁷⁵Ge and ⁷⁰Ge isotopic compositions, and doping these crystals by the neutron transmutation doping (NTD) technique. The resulting net-impurity concentrations and the compensation ratios are precisely determined by the thermal neutron fluence and the [⁷⁴Ge]/[⁷⁰Ge] ratios of the starting Ge materials, respectively. This method also guarantees unprecedented doping uniformity. Using such samples the authors have conducted four types of electron (hole) transport studies probing the nature of (1) free carrier scattering by neutral impurities, (2) free carrier scattering by ionized impurities, (3) low temperature hopping conduction, and (4) free carrier transport in samples close to the metal-insulator transition.

Characterization of Tolypocladium cylindrosporum (Hypocreales: Ophiocordycipitaceae) and Its Impact Against Aedes aegypti and Aedes albopictus Eggs at Low Temperature.

Science.gov (United States)

Flor-Weiler, Lina B; Rooney, Alejandro P; Behle, Robert W; Muturi, Ephantus J

2017-09-01

We examined the growth characteristics of Tolypocladium cylindrosporum IBT 41712 and its potential to infect eggs of Aedes aegypti and Ae. albopictus at a low temperature (15°C). When grown on Sabouraud dextrose agar supplemented with yeast extract, the IBT 41712 formed white colonies turning to a slightly darker, off-white color when mature. The mycelia bore swollen conidiophores producing smooth-walled, oblong to cylindrical conidia with varying sizes, ranging from 1.5 to 3.5 μm long. To determine the optimum temperature for the fungus, we cultured the fungus at eight temperatures (4°C, 12°C, 15°C, 21°C, 28°C, 33°C, 37°C, and 40°C) and measured the diametric growth. The optimum temperature for growth was 28°C since it had the highest diametric growth rate (2.1 ± 0.05 mm/day) and the fastest sporulation period (within 8-10 days of incubation). There was no fungal growth at the 3 highest temperatures (33°C, 37°C, and 40°C) but plates incubated at 33°C, when shifted to optimal temperature (28°C), showed visible growth indicating that following incubation at 33°C, the fungus remained viable. The IBT 41712 successfully infected mosquito eggs at 15°C. Fungal treatment induced egg hatch on moist seed-germination paper and this effect was more pronounced in Ae. aegypti compared to Ae. albopictus. When treated eggs were immersed in dH 2 O 21 days posttreatment, larval hatch of both Ae. aegypti (control = 91%, 1 × 10 7 conidia/ml, fungal treatment = 0%) and Ae. albopictus (control = 85%, fungal treatment = 28%) was significantly lower in fungal treatment compared to the controls. The ability of the strain to grow in a wide temperature range, and effectively infect mosquito eggs and induce egg hatch at a low temperature warrants further investigation for its potential as a mosquito control agent targeting eggs that overwinter or undergo long diapause.

Variability of Germinative Potential among Pathogenic Species of Aspergillus

OpenAIRE

Araujo, Ricardo; Rodrigues, Acacio Gonçalves

2004-01-01

The objective of our study was to evaluate parameters influencing the germination of Aspergillus conidia. Inoculum concentration and age significantly influenced germination. Different incubation temperatures revealed significant differences among Aspergillus species. The internal human milieu provides the ideal conditions for the development of invasive disease by Aspergillus fumigatus but restricts invasion by Aspergillus flavus and Aspergillus niger.

Environmental filtering drives the shape and breadth of the seed germination niche in coastal plant communities.

Science.gov (United States)

Fernández-Pascual, Eduardo; Pérez-Arcoiza, Adrián; Prieto, José Alberto; Díaz, Tomás E

2017-05-01

A phylogenetic comparative analysis of the seed germination niche was conducted in coastal plant communities of western Europe. Two hypotheses were tested, that (1) the germination niche shape (i.e. the preference for a set of germination cues as opposed to another) would differ between beaches and cliffs to prevent seedling emergence in the less favourable season (winter and summer, respectively); and (2) the germination niche breadth (i.e. the amplitude of germination cues) would be narrower in the seawards communities, where environmental filtering is stronger. Seeds of 30 specialist species of coastal plant communities were collected in natural populations of northern Spain. Their germination was measured in six laboratory treatments based on field temperatures. Germination niche shape was estimated as the best germination temperature. Germination niche breadth was calculated using Pielou's evenness index. Differences between plant communities in their germination niche shape and breadth were tested using phylogenetic generalized least squares regression (PGLS). Germination niche shape differed between communities, being warm-cued in beaches (best germination temperature = 20 °C) and cold-cued in cliffs (14 °C). Germination niche was narrowest in seawards beaches (Pielou's index = 0·89) and broadest in landwards beaches (0·99). Cliffs had an intermediate germination niche breadth (0·95). The relationship between niche and plant community had a positive phylogenetic signal for shape (Pagel's λ = 0·64) and a negative one for breadth (Pagel's λ = -1·71). Environmental filters shape the germination niche to prevent emergence in the season of highest threat for seedling establishment. The germination niche breadth is narrower in the communities with stronger environmental filters, but only in beaches. This study provides empirical support to a community-level generalization of the hypotheses about the environmental drivers of the germination

Proteomic Analysis of Lettuce Seed Germination and Thermoinhibition by Sampling of Individual Seeds at Germination and Removal of Storage Proteins by Polyethylene Glycol Fractionation1

Science.gov (United States)

Song, Bin-Yan; Deng, Zhi-Jun; Wang, Yue; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

2015-01-01

Germination and thermoinhibition in lettuce (Lactuca sativa ‘Jianyexianfeng No. 1’) seeds were investigated by a proteomic comparison among dry seeds, germinated seeds at 15°C, at 15°C after imbibition at 25°C for 48 h, or at 25°C in KNO3 (all sampled individually at germination), and ungerminated seeds at 25°C, a thermoinhibitory temperature. Before two-dimensional gel electrophoresis analysis, storage proteins (greater than 50% of total extractable protein) were removed by polyethylene glycol precipitation, which significantly improved the detection of less abundant proteins on two-dimensional gels. A total of 108 protein spots were identified to change more than 2-fold (P lettuce seed germination and thermoinhibition. Accumulation of three proteins and expression of five genes participating in the mevalonate (MVA) pathway of isoprenoid biosynthesis correlated positively with seed germinability. Inhibition of this pathway by lovastatin delayed seed germination and increased the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination and thermoinhibition. PMID:25736209

Temperatures during flower bud development affect pollen germination, self-incompatibility reaction and early fruit development of clementine (Citrus clementina Hort. ex Tan.).

Science.gov (United States)

Distefano, G; Gentile, A; Hedhly, A; La Malfa, S

2018-03-01

One of the key environmental factors affecting plant reproductive systems is temperature. Characterising such effects is especially relevant for some commercially important genera such as Citrus. In this genus, failure of fertilisation results in parthenocarpic fruit development and seedlessness, which is a much-prized character. Here, we characterise the effects of temperature on flower and ovary development, and on pollen-pistil interactions in 'Comune' clementine (Citrus clementina Hort. ex Tan.). We examine flower bud development, in vitro pollen germination and pollen-pistil interaction at different temperatures (15, 20, 25 or 30 °C). These temperatures span the range from 'cold' to 'hot' weather during the flowering season in many citrus-growing regions. Temperature had a strong effect on flower and ovary development, pollen germination, and pollen tube growth kinetics. In particular, parthenocarpic fruit development (indicated by juice vesicle growth) was initiated early if flowers were exposed to warmer temperatures during anthesis. Exposure to different temperatures during flower bud development also alters expression of the self-incompatibility reaction. This affects the point in the pistil at which pollen tube growth is arrested and confirms the role of sub- and supra-optimal temperatures in determining the numbers of pollen tubes reaching the ovary. © 2017 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

Performance Assessment of Low-Temperature Thermal Storage with Electromagnetic Control

Directory of Open Access Journals (Sweden)

Ya-Wei Lee

2014-08-01

Full Text Available This study presents electromagnetic-controlled thermal storage (ECTS that can be directly implemented in strategies of low-temperature waste heat recovery for energy-consuming equipment. A magnetic nanofluid (MNF prepared from fine iron ferrite ferromagnetic particles is recommended as a latent heat medium (LHM. During electromagnetic induction, local flow fluctuations are generated and thermal convection in the MNF can be enhanced. The achieved results demonstrated that ECTS has a wide operational range and an optimum storage efficiency of 84.46%. Thus, a self-perturbation mode used to enhance thermal energy transportation can be designed for numerous waste heat management applications.

Germination and Seedling Growth of Water Primroses: A Cross Experiment between Two Invaded Ranges with Contrasting Climates

Directory of Open Access Journals (Sweden)

Morgane Gillard

2017-09-01

Full Text Available Aquatic ecosystems are vulnerable to biological invasions, and will also be strongly impacted by climate change, including temperature increase. Understanding the colonization dynamics of aquatic invasive plant species is of high importance for preservation of native biodiversity. Many aquatic invasive plants rely on clonal reproduction to spread, but mixed reproductive modes are common. Under future climate changes, these species may favor a sexual reproductive mode. The aim of this study was to test the germination capacity and the seedling growth of two water primrose species, Ludwigia hexapetala and Ludwigia peploides, both invasive in Europe and in the United States. We performed a reciprocal transplant of seeds of L. hexapetala and L. peploides from two invasive ranges into experimental gardens characterized by Oceanic and Mediterranean-type climates. Our results showed that higher temperatures increased or maintained germination percentages and velocity, decreased survivorship of germinants, but increased their production of biomass. The origin of the seeds had low impact on L. hexapetala responses to temperature, but greatly influenced those of L. peploides. The invasiveness of water primroses in ranges with Oceanic climates might increase with temperature. The recruitment from seed banks by these species should be considered by managers to improve the conservation of native aquatic and wetland plant species.

Study Some Ecological Characteristics on Germination and Seedling Growth of Milky Thistle (Silybum marianum (L. Gaertn

Directory of Open Access Journals (Sweden)

E. Zeidali

2017-12-01

Full Text Available Introduction: Milky thistle (Silybum marianum is an annual or biennial plant of the Asteraceae family. Possibly native near the coast of southeast England, it has been widely introduced outside its natural range, for example into North America, Iran, Australia and New Zealand where it is considered an invasive weed. Seed is an important stage of plant life history. Most invasive plants primarily rely on seedling recruitment for population establishment and persistence. The rapid spread of many invasive plants is frequently correlated with special seed traits. Seed trait variations exist not only among species but also within species. Seed traits variations within a species are essential for the seedling establishment at different habitats. Environmental factors, such as temperature, soil solution osmotic potential, solution pH, light quality, management practices and seed location in the soil seedbank, affect weed seed germination and emergence. Fluctuations in temperature can influence seed germination differently than those under constant temperatures; however, such information is not available on Milky thistle. A light requirement for germination is the principal means by which germination can be restricted to an area close to the soil surface, and species requiring light for germination are potentially more likely to be prevalent in no-till and pasture systems. Soil pH affects the development and competitiveness of crops and weeds by affecting the availability of essential minerals, nutrients, the solubility of toxic elements, and soil microflora. Seed burial depth (buried by tillage or other means also affects germination and seedling emergence of several weed species. Better knowledge of the factors that influence seed germination and seedling emergence of Milky thistle could contribute to the development of control measures and help determine its potential for invasion into new areas. The objectives of this study, therefore, were to

[Study on morphology, quality and germination characteristics of Acanthopanax trifoliatus seeds under different habitats].

Science.gov (United States)

Xiao, Juan

2014-05-01

To preliminary explore the difference of the morphological, quality and germinal characteristics of Acanthopanax trifoliatus seeds under different habitats. Collect the wild seeds from different habitats in West Mountain, and then observe their external appearances and internal structure, and test the thousand seeds weight,water content and seed vigor. What's more, the influence to germination rates of the seeds from different temperatures and light intensities in artificial bioclimatic chamber was studied. Orthogonal test in experimental plots was carried out to screen the different sowing dates, matrix types and soil depths which may influence germination rate. The external appearances and quality characteristics of wild seeds from three habitats were different. Seeds could germinate in the both light and dark, the germination rate of the habitat II was as high as 70.5% at the optimum temperature 20 degrees C in artificial bioclimatic chamber. The optimal combination A1, B1, C1 was screened out through orthogonal test, namely, the germination rate would be the highest when the seeds sowed in autumn covering with 2 cm depth of matrix type which component of the ratio of soil, sand and organic fertilizer was 6: 3: 1. There was significant difference in the morphology and germination rate of the three habitats seeds. The habitat II seeds were the optimal choice when culture seedling. The influences of different temperatures on germination rate were different, and the dried seeds should sow in current autumn, better than the next spring.

Control system for Fermilab`s low temperature upgrade

Energy Technology Data Exchange (ETDEWEB)

Norris, B.L.

1996-09-01

Fermilab recently upgraded the Tevatron Cryogenic Systems to allow for lower temperature operation. This Lower Temperature Upgrade grew out of a desire to increase the Colliding Beam Physics energy from 900 GeV to 1000 GeV. A key element in achieving this goal is the new cryogenic control system designed at Fermilab and installed in 24 satellite refrigerators and 8 compressor buildings. The cryogenic improvements and addition hardware like cold compressors exceeded the capability of the original distributed controls package. The new distributed controls package uses a Multibus II platform and Intel`s 80386 microprocessor. Token Ring is used as the link to the systems 6 primary crate locations with Arcnet used as the connection to the systems numerous I/O crates. I/0 capabilities are double the capabilities of the original system. Software has also been upgraded with the introduction of more flexible control loop strategies and Finite State Machines used for automatic sequential control, like quench recovery or cold compressor pump down.

Effect of substrates for in vitro germination of mahogany (Swietenia macrophylla King)

International Nuclear Information System (INIS)

Lameira, Osmar Alves; Da Cunha Lopes, Sebastião; Martins Leão, Noemi Vianna; Castro Coimbra Cordeiro, Iracema Maria; Sousa Reis, Lana Roberta

2006-01-01

The objective of this work was to verify the effect of substrates and different light conditions and temperature on in vitro germination of mahogany (Swietenia macrophylla King) seeds for the production of explants for the initialprocess of micropropagation. In the first experiment the seeds were inoculatedintwosubstrates: 7gL -1 agar and vermiculite,maintained at temperature of 25±1°C with photoperiod of 16 hours and 52 mmol m -2 s -1 irradiance. MS medium supplementedwith sucrose (10; 20; and 30g L -1 ) was used. For the second experiment the seeds were submitted to light conditions (presence and absence)and temperature (25 and 30 °C) and inoculated in MS medium supplementedwith 30g L -1 sucrose +vermiculite. The vermiculite was more efficient than agar as substrate for the in vitro seed germination of mahogany. The MS medium, supplemented with 30g L -1 sucrose + vermiculite, was more efficient for the in vitro seed germination of mahogany. The temperatures of 25 and 30 °C independent of the presence or absence of light had no influence in the number and time for the in vitro germination of these seeds. (author) [pt

Clarifying the role of fire heat and daily temperature fluctuations as germination cues for Mediterranean Basin obligate seeders.

Science.gov (United States)

Santana, Victor M; Baeza, M Jaime; Blanes, M Carmen

2013-01-01

This study aims to determine the role that both direct effects of fire and subsequent daily temperature fluctuations play in the seed bank dynamics of obligate seeders from the Mediterranean Basin. The short yet high soil temperatures experienced due to passage of fire are conflated with the lower, but longer, temperatures experienced by daily fluctuations which occur after removing vegetation. These germination cues are able to break seed dormancy, but it is difficult to assess their specific level of influence because they occur consecutively after summer fires, just before the flush of germination in the wet season (autumn). By applying experimental fires, seed treatments were imposed that combined fire exposure/non-fire exposure with exposure to microhabitats under a gradient of disturbance (i.e. gaps opened by fire, mechanical brushing and intact vegetation). The seeds used were representative of the main families of obligate seeders (Ulex parviflorus, Cistus albidus and Rosmarinus officinalis). Specifically, an assessment was made of (1) the proportion of seeds killed by fire, (2) seedling emergence under field conditions and (3) seeds which remained ungerminated in soil. For the three species studied, the factors that most influenced seedling emergence and seeds remaining ungerminated were microhabitats with higher temperature fluctuations after fire (gaps opened by fire and brushing treatments). The direct effect of fire decreased the seedling emergence of U. parviflorus and reduced the proportion of seeds of R. officinalis remaining ungerminated. The relevance of depleting vegetation (and subsequent daily temperature fluctuation in summer) suggests that studies focusing on lower temperature thresholds for breaking seed dormancy are required. This fact also supports the hypothesis that the seeding capacity in Mediterranean Basin obligate seeders may have evolved as a response to a wide range of disturbances, and not exclusively to fire.

Effect of germination and thermal treatments on folates in rye.

Science.gov (United States)

Kariluoto, Susanna; Liukkonen, Kirsi-Helena; Myllymäki, Olavi; Vahteristo, Liisa; Kaukovirta-Norja, Anu; Piironen, Vieno

2006-12-13

Effects of germination conditions and thermal processes on folate contents of rye were investigated. Total folate contents were determined microbiologically with Lactobacillus rhamnosus (ATCC 7469) as the growth indicator organism, and individual folates were determined by high-performance liquid chromatography after affinity chromatographic purification. Germination increased the folate content by 1.7-3.8-fold, depending on germination temperature, with a maximum content of 250 micro g/100 g dry matter. Hypocotylar roots with their notably high folate concentrations (600-1180 micro g/100 g dry matter) contributed 30-50% of the folate contents of germinated grains. Germination altered the proportions of folates, increasing the proportion of 5-methyltetrahydrofolate and decreasing the proportion of formylated folate compounds. Thermal treatments (extrusion, autoclaving and puffing, and IR and toasting) resulted in significant folate losses. However, folate levels in grains that were germinated and then were heat processed were higher than for native (nongerminated) grains. Opportunities to optimize rye processing to enhance folate levels in rye-based foods are discussed.

Development of a low-temperature two-stage fluidized bed incinerator for controlling heavy-metal emission in flue gases

International Nuclear Information System (INIS)

Peng, Tzu-Huan; Lin, Chiou-Liang; Wey, Ming-Yen

2014-01-01

This study develops a low-temperature two-stage fluidized bed system for treating municipal solid waste. This new system can decrease the emission of heavy metals, has low construction costs, and can save energy owing to its lower operating temperature. To confirm the treatment efficiency of this system, the combustion efficiency and heavy-metal emission were determined. An artificial waste containing heavy metals (chromium, lead, and cadmium) was used in this study. The tested parameters included first-stage temperature and system gas velocity. Results obtained using a thermogravimetric analyzer with a differential scanning calorimeter indicated that the first-stage temperature should be controlled to at least 400 °C. Although, a large amount of carbon monoxide was emitted after the first stage, it was efficiently consumed in the second. Loss of the ignition values of ash residues were between 0.005% and 0.166%, and they exhibited a negative correlation with temperature and gas velocity. Furthermore, the emission concentration of heavy metals in the two-stage system was lower than that of the traditional one-stage fluidized bed system. The heavy-metal emissions can be decreased by between 16% and 82% using the low-temperature operating process, silica sand adsorption, and the filtration of the secondary stage. -- Graphical abstract: Heavy-metal emission concentrations in flue gases under different temperatures and gas velocities (dashed line: average of the heavy-metal emission in flue gases in the one-stage fluidized-bed incinerator). Highlights: • Low temperature two-stage system is developed to control heavy metal. • The different first-stage temperatures affect the combustion efficiency. • Surplus CO was destroyed efficiently by the secondary fluidized bed combustor. • Metal emission in two-stage system is lower than in the traditional system. • Temperature, bed adsorption, and filtration are the main control mechanisms

Automatic low-temperature calorimeter

International Nuclear Information System (INIS)

Malyshev, V.M.; Mil'ner, G.A.; Shibakin, V.F.; Sorkin, E.L.

1986-01-01

This paper describes a low-temperature adiabatic calorimeter with a range of 1.5-500K. The system for maintaining adiabatic conditions is implemented by two resitance thermometers, whose sensitivity at low temperatures is several orders higher than that of thermocouples. The calorimeter cryostat is installed in an STG-40 portable Dewar flask. The calorimeter is controlled by an Elektronika-60 microcomputer. Standard platinum and germanium thermometers were placed inside of the calorimeter to calibrate the thermometers of the calorimeter and the shield, and the specific heats of specimens of OSCh 11-4 copper and KTP-8 paste were measured to demonstrate the possibilities of the described calorimeter. Experience with the calorimeter has shown that a thorough study of the dependence of heat capacity on temperature (over 100 points for one specimen) can be performed in one or two dats

Effect of population, collection year, after-ripening and incubation condition on seed germination of Stipa bungeana.

Science.gov (United States)

Zhang, Rui; Baskin, J M; Baskin, C C; Mo, Qing; Chen, Lijun; Hu, Xiaowen; Wang, Yanrong

2017-10-24

Knowledge of the germination behavior of different populations of a species can be useful in the selection of appropriate seed sources for restoration. The aim of this study was to test the effect of seed population, collection year, after-ripening and incubation conditions on seed dormancy and germination of Stipa bungeana, a perennial grass used for revegetation of degraded grasslands on the Loess Plateau, China. Fresh S. bungeana seeds were collected from eight locally-adapted populations in 2015 and 2016. Dormancy and germination characteristics of fresh and 6-month-old dry-stored seeds were determined by incubating them over a range of alternating temperature regimes in light. Effect of water stress on germination was tested for fresh and 6-month-old dry-stored seeds. Seed dormancy and germination of S. bungeana differed with population and collection year. Six months of dry storage broke seed dormancy, broadened the temperature range for germination and increased among-population differences in germination percentage. The rank order of germination was not consistent in all germination tests, and it varied among populations. Thus, studies on comparing seed dormancy and germination among populations must consider year of collection, seed dormancy states and germination test conditions when selecting seeds for grassland restoration and management.

Fluridone and norflurazon, carotenoid-biosynthesis inhibitors, promote seed conditioning and germination of the holoparasite Orobanche minor.

Science.gov (United States)

Chae, Sang Heon; Yoneyama, Koichi; Takeuchi, Yasutomo; Joel, Daniel M.

2004-02-01

Fluridone and norflurazon, two carotenoid-biosynthesis inhibitors, shortened the conditioning period required by seeds of Orobanche minor in order to respond to the germination stimulant strigol. Neither fluridone nor norflurazon alone induced seed germination of O. minor, they promoted strigol-induced germination. In addition, these compounds restored the conditioning and germination of seeds at a supraoptimal temperature (30 degrees C) as well as in the light. Gibberellic acid (GA(3)) showed similar promotive and protective effects on the conditioning and germination of O. minor seeds. Although fluridone and norflurazon are known to prevent abscisic acid (ABA)-biosynthesis, and stresses such as supraoptimal temperatures have been reported to induce ABA accumulation in plants, the amount of ABA in the seeds or that released from the seeds into the conditioning media was not affected by the fluridone treatment and by exposure to the supraoptimal temperature. These results indicate that the promotive and protective effects of fluridone and norflurazon on the conditioning and germination of O. minor seeds would be attributed to other perturbations rather than the inhibition of ABA-biosynthesis.

The interactive effect of phosphorus and nitrogen on "in vitro" spore germination of Glomus etunicatum Becker & Gerdemann, root growth and mycorrhizal colonization

Directory of Open Access Journals (Sweden)

Bressan Wellington

2001-01-01

Full Text Available The effects of P and N amendment and its interactions on spore germination, root growth and colonized root length by Glomus etunicatum Becker & Gerdemann (INVAM S329 was studied "in vitro" in RiT - DNA transformed roots of Anthylis vulneraria sub sp. Sampaiana (Kidney vetch. Three N media concentrations (5, 10 and 50 mg/l at P constant level (2 mg/l and three P media concentrations (2, 10 and 20 mg/l at N constant level (5 mg/l were utilized as a treatment. Bécard & Fortin medium was used as a basal medium for root growth and colonized root length, and water/agar (0.8% media was the control for spore germination. Spore germination of G. etunicatum at low P level was reduced by N addition in relation to the control media, and at low N level addition of P stimulated spore germination. Total root length was stimulated by N addtion at low P level, but no significant difference (p£0.05 was observed between 10 and 50 mg/l of N. P addition at low N level media also stimulated total root growth, and a significant difference (p£0.05 was observed among P concentrations. Colonized root length by G. etunicatum increased significantly (p£0.05 with P additions at low N levels. Under low P level no significant differences was found between 10 and 50 mg/l of N. These results demonstrate that the interaction between P and N affect differently spore germination, root growth and colonized root lenght.

Germination of Themeda triandra (Kangaroo grass) as affected by ...

African Journals Online (AJOL)

Low rainfall in range areas restricts germination, growth and development of majority of range grasses. However, germination and establishment potential of forage grasses vary and depends on environmental conditions. Themeda triandra is an excellent known grass to grow under different environmental conditions.

Herbicide impact on Hormosira banksii gametes measured by fluorescence and germination bioassays

International Nuclear Information System (INIS)

Seery, Cliff R.; Gunthorpe, Leanne; Ralph, Peter J.

2006-01-01

The innovative bioassay described here involves chlorophyll a fluorescence measurements of gametes from the macroalgae, Hormosira banksii, where gametes (eggs) were exposed to Diuron, Irgarol and Bromacil. Response was assessed as percent inhibition from control of effective quantum yield (ΔF/Fm') of photosystem II, herein referred to as % PSII Inhibition. This was measured with the dual-channelled pulse amplitude modulated (PAM) fluorometer, ToxY-PAM. The fluorescence bioassay was run simultaneously with an established H. banksii germination bioassay to compare sensitivity, precision, and time-to-result. The fluorescence bioassay gave highly sensitive results evidenced by EC 5 s (% PSII Inhibition) for Diuron, Irgarol and Bromacil being three, four and three orders of magnitude (respectively) lower than EC 5 s generated from the germination bioassays. Precision of the fluorescence bioassay was demonstrated with low coefficient of variations (<30%) for all three toxicants. With regard to time, the fluorescence bioassay gave results within 6 h, as opposed to more than 50 h for the germination bioassay. - Chlorophyll a fluorescence measurements form the basis of a macroalgal bioassay with many advantages over germination-based methods

Effects of Germination and Fermentation on the Functionality of Whole Soy Flour

Directory of Open Access Journals (Sweden)

Livia Patrascu

2016-11-01

Full Text Available Nutritional quality and technological performances of grains can be modulated through germination and controlled fermentation. The aim of the work was to estimate the effect of germination (72 h at 23oC and fermentation on the fundamental rheological properties of the soy flour based suspensions and sourdoughs, and to assess the bread making potential of the whole soy flours by considering the thermo-mechanical functionality of soy in admixture with white wheat flour. Soy flour based sourdough were prepared using three different starter cultures, consisting of mixtures of lactic acid bacteria like Lactobacillus plantarum, Lb. brevis, Lb. rhamnosus, Lb. casei, Lb. acidophilus, Bifidobacterium BB12®, and Streptococcus thermophilus and/or yeast Kluyveromyces marxianus subsp. Marxianus. The rheological behaviour of the suspensions and sourdoughs was influenced by the soy germination and fermentation processes. The stress sweep tests indicated significant narrowing of the linear viscoelastic regions, as well as the decrease of the stress values required for the beginning of flow. The temperature ramp test showed more intense swelling in case of the germinated and fermented samples. Both native and germinated soy flours were used to replace 15% of the wheat flour, and the Mixolab test indicated that the germination process caused the decrease of protein weakening and dough stability. The sourdoughs addition to the wheat flour resulted in significant changes of the thermo-mechanical properties of the dough. Properties related to stability of starch gel during heating, starch gelatinization and retrogradation depended on the type of starter culture used for fermentation.

Smoke-induced seed germination in California chaparral

Science.gov (United States)

Keeley, J.E.; Fotheringham, C.J.

1998-01-01

The California chaparral community has a rich flora of species with different mechanisms for cuing germination to postfire conditions. Heat shock triggers germination of certain species but has no stimulatory effect on a great many other postfire species that are chemically stimulated by combustion products. Previous reports have shown that charred wood will induce germination, and here we report that smoke also induces germination in these same species. Smoke is highly effective, often inducing 100% germination in deeply dormant seed populations with 0% control germination. Smoke induces germination both directly and indirectly by aqueous or gaseous transfer from soil to seeds. Neither nitrate nor ammonium ions were effective in stimulating germination of smoke-stimulated species, nor were most of the quantitatively important gases generated by biomass smoke. Nitrogen dioxide, however, was very effective at inducing germination in Caulanthus heterophyllus (Brassicaceae), Emmenanthe penduliflora (Hydrophyllaceae), Phacelia grandiflora (Hydrophyllaceae), and Silene multinervia (Caryophyllaceae). Three species, Dendromecon rigida (Papaveraceae), Dicentra chrysantha, and Trichostema lanatum (Lamiaceae), failed to germinate unless smoke treatment was coupled with prior treatment of 1 yr soil storage. Smoke-stimulated germination was found in 25 chaparral species, representing 11 families, none of which were families known for heat-shock-stimulated germination. Seeds of smoke-stimulated species have many analogous characteristics that separate them from most heat-shock-stimulated seeds, including: (1) outer seed coats that are highly textured, (2) a poorly developed outer cuticle, (3) absence of a dense palisade tissue in the seed coat, and (4) a subdermal membrane that is semipermeable, allowing water passage but blocking entry of large (molecular mass > 500) solutes. Tentative evidence suggests that permeability characteristics of this subdermal layer are altered by

Seed germination in relation to the invasiveness in spiny amaranth and edible amaranth in Xishuangbanna, SW China.

Science.gov (United States)

Ye, Juan; Wen, Bin

2017-01-01

Both spiny and edible amaranths (Amaranthus spinosus and A. tricolor) are exotic annuals in China that produce numerous small seeds every year. Spiny amaranth has become a successful invader and a troublesome weed in Xishuangbanna, but edible amaranth has not, although it is widely grown as a vegetable there. As seed germination is one of the most important life-stages contributing to the ability of a plant to become invasive, we conducted experiments to compare the effects of high temperature and water stress on seed germination in two varieties each of spiny amaranth and edible amaranth. Overall, the seeds of both amaranth species exhibited adaptation to high temperature and water stress, including tolerance to ground temperatures of 70°C for air-dried seeds, which is consistent with their behavior in their native ranges in the tropics. As expected, the invasive spiny amaranth seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 45°C, and to imbibition-desiccation treatment, compared to edible amaranth seeds. Unexpectedly, edible amaranth seeds exhibited higher germination at extreme temperatures (10°C, 15°C, and 40°C), and at lower water potential (below -0.6 MPa). It is likely that cultivation of edible amaranth has selected seed traits that include rapid germination and germination under stressful conditions, either of which, under natural conditions, may result in the death of most germinating edible amaranth seeds and prevent them from becoming invasive weeds in Xishuangbanna. This study suggests that rapid germination and high germination under stress conditions-excellent seed traits for crops and for many invasive species-might be a disadvantage under natural conditions if these traits are asynchronous with natural local conditions that support successful germination.

Seed germination in relation to the invasiveness in spiny amaranth and edible amaranth in Xishuangbanna, SW China.

Directory of Open Access Journals (Sweden)

Juan Ye

Full Text Available Both spiny and edible amaranths (Amaranthus spinosus and A. tricolor are exotic annuals in China that produce numerous small seeds every year. Spiny amaranth has become a successful invader and a troublesome weed in Xishuangbanna, but edible amaranth has not, although it is widely grown as a vegetable there. As seed germination is one of the most important life-stages contributing to the ability of a plant to become invasive, we conducted experiments to compare the effects of high temperature and water stress on seed germination in two varieties each of spiny amaranth and edible amaranth. Overall, the seeds of both amaranth species exhibited adaptation to high temperature and water stress, including tolerance to ground temperatures of 70°C for air-dried seeds, which is consistent with their behavior in their native ranges in the tropics. As expected, the invasive spiny amaranth seeds exhibited higher tolerance to both continuous and daily periodic high-temperature treatment at 45°C, and to imbibition-desiccation treatment, compared to edible amaranth seeds. Unexpectedly, edible amaranth seeds exhibited higher germination at extreme temperatures (10°C, 15°C, and 40°C, and at lower water potential (below -0.6 MPa. It is likely that cultivation of edible amaranth has selected seed traits that include rapid germination and germination under stressful conditions, either of which, under natural conditions, may result in the death of most germinating edible amaranth seeds and prevent them from becoming invasive weeds in Xishuangbanna. This study suggests that rapid germination and high germination under stress conditions-excellent seed traits for crops and for many invasive species-might be a disadvantage under natural conditions if these traits are asynchronous with natural local conditions that support successful germination.

Phylogeny and source climate impact seed dormancy and germination of restoration-relevant forb species.

Science.gov (United States)

Seglias, Alexandra E; Williams, Evelyn; Bilge, Arman; Kramer, Andrea T

2018-01-01

For many species and seed sources used in restoration activities, specific seed germination requirements are often unknown. Because seed dormancy and germination traits can be constrained by phylogenetic history, related species are often assumed to have similar traits. However, significant variation in these traits is also present within species as a result of adaptation to local climatic conditions. A growing number of studies have attempted to disentangle how phylogeny and climate influence seed dormancy and germination traits, but they have focused primarily on species-level effects, ignoring potential population-level variation. We examined the relationships between phylogeny, climate, and seed dormancy and germination traits for 24 populations of eight native, restoration-relevant forb species found in a wide range of climatic conditions in the Southwest United States. The seeds were exposed to eight temperature and stratification length regimes designed to mimic regional climatic conditions. Phylogenetic relatedness, overall climatic conditions, and temperature conditions at the site were all significantly correlated with final germination response, with significant among-population variation in germination response across incubation treatments for seven of our eight study species. Notably, germination during stratification was significantly predicted by precipitation seasonality and differed significantly among populations for seven species. While previous studies have not examined germination during stratification as a potential trait influencing overall germination response, our results suggest that this trait should be included in germination studies as well as seed sourcing decisions. Results of this study deepen our understanding of the relationships between source climate, species identity, and germination, leading to improved seed sourcing decisions for restorations.

Requirement for ethylene synthesis and action during relief of thermoinhibition of lettuce seed germination by combinations of gibberellic acid, kinetin, and carbon dioxide

International Nuclear Information System (INIS)

Saini, H.S.; Consolacion, E.D.; Bassi, P.K.; Spencer, M.S.

1986-01-01

Application of exogenous ethylene in combination with gibberellic acid (GA 3 ), kinetin (KIN), and/or CO 2 has been reported to induce germination of lettuce seeds at supraoptimal temperatures. However, it is not clear whether endogenous ethylene also plays a mediatory role when germination under these conditions is induced by treatment regimes that do not include ethylene. Therefore, possible involvement of endogenous ethylene during the relief of thermoinhibition of lettuce (Lactuca sativa L. cv Grand Rapids) seed germination at 32°C was investigated. Combinations of GA 3 (0.5 millimolar), KIN (0.05 millimolar), and CO 2 (10%) were used to induce germination. Little germination occurred in controls or upon treatment with ethylene, KIN, or CO 2 . Neither KIN nor CO 2 affected the rate of ethylene production by seeds. Both germination and ethylene production were slightly promoted by GA 3 . Treatments with GA 3 + CO 2 , GA 3 + KIN, or GA 3 + CO 2 + KIN resulted in approximately 10- to 40-fold increases in ethylene production and 50 to 100% promotion of germination as compared to controls. Initial ethylene evolution from the treated seeds was greater than from the controls and a major surge in ethylene evolution occurred at the time of visible germination. Application of 1 millimolar 2-aminoethoxyvinyl glycine (AVG), an inhibitor of ethylene synthesis, in combination with any of above three treatments inhibited the ethylene production to below control levels. This was accompanied by a marked decline in germination percentage. Germination was also inhibited by 2,5-norbornadiene (0.25-2 milliliters per liter), a competitive inhibitor of ethylene action. Application of exogenous ethylene (1-100 microliters per liter) overcame the inhibitory effects of AVG and 2,5-norbornadiene on germination. The results demonstrate that endogenous ethylene synthesis and action are essential for the alleviation of thermoinhibition of lettuce seeds by combinations of GA 3 , KIN, and CO

Requirement for Ethylene Synthesis and Action during Relief of Thermoinhibition of Lettuce Seed Germination by Combinations of Gibberellic Acid, Kinetin, and Carbon Dioxide.

Science.gov (United States)

Saini, H S; Consolacion, E D; Bassi, P K; Spencer, M S

1986-08-01

Application of exogenous ethylene in combination with gibberellic acid (GA(3)), kinetin (KIN), and/or CO(2) has been reported to induce germination of lettuce seeds at supraoptimal temperatures. However, it is not clear whether endogenous ethylene also plays a mediatory role when germination under these conditions is induced by treatment regimes that do not include ethylene. Therefore, possible involvement of endogenous ethylene during the relief of thermoinhibition of lettuce (Lactuca sativa L. cv Grand Rapids) seed germination at 32 degrees C was investigated. Combinations of GA(3) (0.5 millimolar), KIN (0.05 millimolar), and CO(2) (10%) were used to induce germination. Little germination occurred in controls or upon treatment with ethylene, KIN, or CO(2). Neither KIN nor CO(2) affected the rate of ethylene production by seeds. Both germination and ethylene production were slightly promoted by GA(3). Treatments with GA(3)+CO(2), GA(3)+KIN, or GA(3)+CO(2)+KIN resulted in approximately 10-to 40-fold increases in ethylene production and 50 to 100% promotion of germination as compared to controls. Initial ethylene evolution from the treated seeds was greater than from the controls and a major surge in ethylene evolution occurred at the time of visible germination. Application of 1 millimolar 2-aminoethoxyvinyl glycine (AVG), an inhibitor of ethylene synthesis, in combination with any of above three treatments inhibited the ethylene production to below control levels. This was accompanied by a marked decline in germination percentage. Germination was also inhibited by 2,5-norbornadiene (0.25-2 milliliters per liter), a competitive inhibitor of ethylene action. Application of exogenous ethylene (1-100 microliters per liter) overcame the inhibitory effects of AVG and 2,5-norbornadiene on germination. The results demonstrate that endogenous ethylene synthesis and action are essential for the alleviation of thermoinhibition of lettuce seeds by combinations of GA(3), KIN

Contrasting germination responses to vegetative canopies experienced in pre- vs. post-dispersal environments

Science.gov (United States)

Leverett, Lindsay D.; Auge, Gabriela A.; Bali, Aman; Donohue, Kathleen

2016-01-01

Background Seeds adjust their germination based on conditions experienced before and after dispersal. Post-dispersal cues are expected to be more accurate predictors of offspring environments, and thus offspring success, than pre-dispersal cues. Therefore, germination responses to conditions experienced during seed maturation may be expected to be superseded by responses to conditions experienced during seed imbibition. In taxa of disturbed habitats, neighbours frequently reduce the performance of germinants. This leads to the hypotheses that a vegetative canopy will reduce germination in such taxa, and that a vegetative canopy experienced during seed imbibition will over-ride germination responses to a canopy experienced during seed maturation, since it is a more proximal cue of immediate competition. These hypotheses were tested here in Arabidopsis thaliana. Methods Seeds were matured under a simulated canopy (green filter) or white light. Fresh (dormant) seeds were imbibed in the dark, white light or canopy at two temperatures (10 or 22 °C), and germination proportions were recorded. Germination was also recorded in after-ripened (less dormant) seeds that were induced into secondary dormancy and imbibed in the dark at each temperature, either with or without brief exposure to red and far-red light. Key Results Unexpectedly, a maturation canopy expanded the conditions that elicited germination, even as seeds lost and regained dormancy. In contrast, an imbibition canopy impeded or had no effect on germination. Maturation under a canopy did not modify germination responses to red and far-red light. Seed maturation under a canopy masked genetic variation in germination. Conclusions The results challenge the hypothesis that offspring will respond more strongly to their own environment than to that of their parents. The observed relaxation of germination requirements caused by a maturation canopy could be maladaptive for offspring by disrupting germination responses

Study of Different Priming Treatments on Germination Traits of Soybean Seed Lots

Directory of Open Access Journals (Sweden)

Hossein Reza ROUHI

2011-03-01

Full Text Available Oilseeds are more susceptible to deterioration due to membrane disruption, high free fatty acid level in seeds and free radical production. These factors are tended to less vigorous seed. Priming treatments have been used to accelerate the germination and seedling growth in most of the crops under normal and stress conditions. For susceptible and low vigor soybean seed, this technique would be a promising method. At first, in separate experiment, effects of hydropriming for (12, 24, 36 and 48 h with control (none prime were evaluated on germination traits of soybean seed lots cv. �Sari� (include 2 drying method and 3 harvest moisture. Then, next experiment was conducted to determination the best combination of osmopriming in soybean seed lots, hence 3 osmotic potential level (-8, -10 and -12 bar at 4 time (12, 24, 36 and 48 h were compared. Analysis of variance showed that, except for seedling dry weight, the other traits include standard germination, germination rate, seedling length and vigor index were influenced by osmopriming. Hydropriming had no effect on these traits and decreased rate of germination. Finally the best combination of osmopriming were osmotic potential -12 bar at 12 hours for time, that submitted acceptable result in all conditions and recommended for soybean seed lots cv. �Sari�.

Study of Different Priming Treatments on Germination Traits of Soybean Seed Lots

Directory of Open Access Journals (Sweden)

Hossein Reza ROUHI

2011-03-01

Full Text Available Oilseeds are more susceptible to deterioration due to membrane disruption, high free fatty acid level in seeds and free radical production. These factors are tended to less vigorous seed. Priming treatments have been used to accelerate the germination and seedling growth in most of the crops under normal and stress conditions. For susceptible and low vigor soybean seed, this technique would be a promising method. At first, in separate experiment, effects of hydropriming for (12, 24, 36 and 48 h with control (none prime were evaluated on germination traits of soybean seed lots cv. Sari (include 2 drying method and 3 harvest moisture. Then, next experiment was conducted to determination the best combination of osmopriming in soybean seed lots, hence 3 osmotic potential level (-8, -10 and -12 bar at 4 time (12, 24, 36 and 48 h were compared. Analysis of variance showed that, except for seedling dry weight, the other traits include standard germination, germination rate, seedling length and vigor index were influenced by osmopriming. Hydropriming had no effect on these traits and decreased rate of germination. Finally the best combination of osmopriming were osmotic potential -12 bar at 12 hours for time, that submitted acceptable result in all conditions and recommended for soybean seed lots cv. Sari.

ABA, GA(3), and nitrate may control seed germination of Crithmum maritimum (Apiaceae) under saline conditions.

Science.gov (United States)

Atia, Abdallah; Debez, Ahmed; Barhoumi, Zouhaier; Smaoui, Abderrazak; Abdelly, Chedly

2009-08-01

Impaired germination is common among halophyte seeds exposed to salt stress, partly resulting from the salt-induced reduction of the growth regulator contents in seeds. Thus, the understanding of hormonal regulation during the germination process is a main key: (i) to overcome the mechanisms by which NaCl-salinity inhibit germination; and (ii) to improve the germination of these species when challenged with NaCl. In the present investigation, the effects of ABA, GA(3), NO(-)(3), and NH(+)(4) on the germination of the oilseed halophyte Crithmum maritimum (Apiaceae) were assessed under NaCl-salinity (up to 200 mM NaCl). Seeds were collected from Tabarka rocky coasts (N-W of Tunisia). The exogenous application of GA(3), nitrate (either as NaNO(3) or KNO(3)), and NH(4)Cl enhanced germination under NaCl salinity. The beneficial impact of KNO(3) on germination upon seed exposure to NaCl salinity was rather due to NO(-)(3) than to K(+), since KCl failed to significantly stimulate germination. Under optimal conditions for germination (0 mM NaCl), ABA inhibited germination over time in a dose dependent manner, but KNO(3) completely restored the germination parameters. Under NaCl salinity, the application of fluridone (FLU) an inhibitor of ABA biosynthesis, stimulated substantially seed germination. Taken together, our results point out that NO(-)(3) and GA(3) mitigate the NaCl-induced reduction of seed germination, and that NO(-)(3) counteracts the inhibitory effect of ABA on germination of C. maritimum.

Translatome profiling in dormant and nondormant sunflower (Helianthus annuus) seeds highlights post-transcriptional regulation of germination.

Science.gov (United States)

Layat, Elodie; Leymarie, Juliette; El-Maarouf-Bouteau, Hayat; Caius, José; Langlade, Nicolas; Bailly, Christophe

2014-12-01

Seed dormancy, which blocks germination in apparently favourable conditions, is a key regulatory control point of plant population establishment. As germination requires de novo translation, its regulation by dormancy is likely to be related to the association of individual transcripts to polysomes. Here, the polysome-associated mRNAs, that is, the translatome, were fractionated and characterized with microarrays in dormant and nondormant sunflower (Helianthus annuus) embryos during their imbibition at 10°C, a temperature preventing germination of dormant embryos. Profiling of mRNAs in polysomal complexes revealed that the translatome differs between germinating and nongerminating embryos. Association of transcripts with polysomes reached a maximum after 15 h of imbibition; at this time-point 194 polysome-associated transcripts were specifically found in nondormant embryos and 47 in dormant embryos only. The proteins corresponding to the polysomal mRNAs in nondormant embryos appeared to be very pertinent for germination and were involved mainly in transport, regulation of transcription or cell wall modifications. This work demonstrates that seed germination results from a timely regulated and selective recruitment of mRNAs to polysomes, thus opening novel fields of investigation for the understanding of this developmental process. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

Effect of Estrogen and Progeterone on seed germination

Directory of Open Access Journals (Sweden)

Nirmala

Full Text Available Early pregnancy detection in dairy cattle is an integral part of a successful animal husbandry practice. A simple seed germination technique (Punyakoti test comprises observation of differential seed germination response of wheat seeds to diluted fresh urine samples as reflected by significant inhibition of germination percentage in pregnant cow urine when compared to non pregnant cow urine. Hormone metabolites excreted through urine might affect the seed germination in pregnant cow urine. In the present study an attempt was made to test the effect of hormones (in their natural forms at different concentrations of estrogen (17-ß estradiol and progesterone on wheat and green gram germination. Stock solutions of estrogen and progesterone were prepared in alcohol (1mg/ml and serial dilutions made using distilled water to get the concentrations of T1=10, T2=1, T3=0.1 and T4=0.01 μg/ml respectively in treatment groups. About 15 seeds each of wheat and green gram were taken in sterile Petri dishes into which 15ml of each test preparation was poured. The treatments were compared with distilled water and alcohol controls. The study was conducted for a period of five days during which seed germination was observed after 48 hrs and shoot lengths were also measured by the end of study. The average seed germination and shoot length in treatment groups did not vary significantly (P>0.05 when compared with that of control groups. Thus from the present study, it can be concluded that estrogen and progesterone in their natural form will not affect seed germination and shoot length. [Veterinary World 2008; 1(8.000: 241-242

Germination and growth of Magonia pubescens A. ST.-HIL seedlings

Directory of Open Access Journals (Sweden)

Ani Cátia Giotto

2009-03-01

Full Text Available This study aimed to analyze the germination, growth and development of Magonia pubescens A. St.-Hil. (tinguí ortimbó, a typical species of the deciduous forest. The germination of seeds of four matrices was evaluated at different treatments: directsowing in greenhouse (50% of shade, direct sowing under full sunlight and moistened paper at laboratory condition and underfluorescent light with photoperiod of 12 hours in ambient temperature. The germinated seeds under laboratory conditions weretransplanted to polyethylene bags with soil under full sunlight and 50% of shade. The variables evaluated were: time of the first andlast germination, germinability; average time and the rates of speed of germination index. In addition there were evaluated the seedlingheight, stem base diameter, number of leaf and leaflets were monitored at 30, 60, 90 and 120 days. The species presented highgerminability at laboratory conditions (G> 90% and under full sunlight (96%>G>56%, however, the germinability in 50% shadepresented inferior result (G0.05. The leaf and leaflets number varied among treatments, with highest average for seedling under full sunlight. Suggesting thatMagonia pubescens A. St.-Hil. is a useful species for rehabilitation of degraded areas.

Heat shock and plant leachates regulate seed germination of the endangered carnivorous plant Drosophyllum lusitanicum

Directory of Open Access Journals (Sweden)

S. Gómez-González

2018-01-01

Full Text Available In fire-prone ecosystems, many plant species have specialized mechanisms of seed dormancy that ensure a successful recruitment after fire. A well-documented mechanism is the germination stimulated by fire-related cues, such as heat shock and smoke. However, less is known about the role of inhibitory germination signals (e.g. allelopathy in regulating post-fire recruitment. Plant leachates derived from the unburned vegetation can enforce dormancy by means of allelopathic compounds, acting as a signal of unfavourable (highly competitive niche for germination in pyrophyte species. Here, we assessed the separate effects of heat shock and plant leachates on seed germination of Drosophyllum lusitanicum, an endangered carnivorous plant endemic to Mediterranean fire-prone heathlands. We performed a germination experiment in which seeds were subjected to three treatments: (1 5 min at 100 °C, (2 watering with plant leachate, and (3 control. Germination rate and seed viability was determined after 63 days. Heat shock stimulated seed germination in D. lusitanicum while plant leachates had inhibitory germination effects without reducing seed viability. Thus, both positive and negative signals could be involved in its successful post-fire recruitment. Fire would break seed dormancy and stimulate seed germination of D. lusitanicum through high temperatures, but also by eliminating allelochemical compounds from the soil. These results help to understand the population dynamics patterns found for D. lusitanicum in natural populations, and highlight the role of fire in the ecology and conservation of this endangered species. Seed dormancy imposed by plant-derived leachates as an adaptive mechanism should be considered more in fire ecology theory.

Effect of water and saline stress on germination of Atriplex nummularia (Chenopodiaceae)

International Nuclear Information System (INIS)

Ruiz, Monica B; Parera, Carlos A

2013-01-01

Saline soils, characteristic of arid zones, can affect the germination of the species due to low water potential or ion toxicity. The effect of water and saline stress on germination was evaluated in atriplex nummularia a potential source of forage for arid zones. the seeds were scarified to reduce the inhibitory effect on germination and incubated in at 23 Celsius degrade on germination paper imbibed with solutions of sodium chloride (NaCl) and polyethylene glycol (peg) at three water potentials: -0,5; -1,0 and -1,5 MPA. The percentage germination and germination speed were significantly affected by the concentration of the solution and the solute used. While more negative osmotic potentials, the percentage of germination and germination speed were significantly lower. The seeds germinated in peg solution have higher germination and germination speed than the seeds germinated in NaCl, especially in -1,0 MPA. The data suggest that the seeds of a. nummularia show sensitivity to the presence of Na+ and Cl- ions affecting the germination process.

The Efficacy of Ultramolecular Aqueous Dilutions on a Wheat Germination Model as a Function of Heat and Aging-Time

Directory of Open Access Journals (Sweden)

Maurizio Brizzi

2011-01-01

Full Text Available This study evaluates the effects of temperature and aging on the efficacy of As2O3 at the 45th decimal potency in a wheat germination model, compared against a control and potentized H2O 45×. Each treatment-temperature combination was tested on seeds (Triticum aestivum L. of Pandas variety, using six Petri dishes (33 seeds/dish per trial, performing eight trials. Seeds were pre-treated by poisoning with 0.1% As2O3 solution to reduce germination, to allow a better evaluation of homeopathic treatment effects. The outcome variable was the number of non-germinated seeds after 96 h. Temperature effect was investigated by heating each treatment in a water bath for 30 min (at 20, 40 or 70°C, or for 5 min (at 100°C, and that of aging by dividing experimental data, collected over a period of nearly five months, into two groups: early and late experiments. Results seem to show that the efficacy of As2O3 45× is unaltered at 20 and 40°C, increases at 70°C and decreases at 100°C. As regards aging, a notable difference was found between early trials, with no significant efficacy, and late trials, where As2O3 45× exhibits a repeated significant effect versus control, except at 100°C. A reduction in variability was observed for As2O3 45× at 20°C versus control, confirming the findings of previous work. The main conclusion suggested by this experiment is that the efficacy of As2O3 45× on wheat germination may be influenced by heating degree and seems to have an increasing trend as a function of aging.

The dynamics of acid-soluble phosphorus compounds in the course of winter and spring wheat germination under various thermic conditions. Part II. Labile phosphorus after hydrolysis of the acid-soluble fraction

Directory of Open Access Journals (Sweden)

A. Barbaro

2015-06-01

Full Text Available The changes in labile phosphorus compounds content during germination of wheat were investigated. These compounds were determined in acid-soluble germ extracts separated into fractions according to the solubility of their barium salts. Low germination temperature was found to raise the labile phosphorus content in the fraction of insoluble barium salts. If we assume that labile P of this fraction consisted mainly of adenosinedi- and triphosphates, it would seem that the rise, in the ATP and ADP level under the influence of low temperature may be essential for initiating flowering in winter varieties.

Effects of High Pressure on Bacillus licheniformis Spore Germination and Inactivation.

Science.gov (United States)

Borch-Pedersen, Kristina; Mellegård, Hilde; Reineke, Kai; Boysen, Preben; Sevenich, Robert; Lindbäck, Toril; Aspholm, Marina

2017-07-15

Bacillus and Clostridium species form spores, which pose a challenge to the food industry due to their ubiquitous nature and extreme resistance. Pressurization at 300 MPa likely triggers germination by opening dipicolinic acid (DPA) channels present in the inner membrane of the spores. In this work, we expose spores of Bacillus licheniformis , a species associated with food spoilage and occasionally with food poisoning, to high pressure (HP) for holding times of up to 2 h. By using mutant spores lacking one or several GRs, we dissect the roles of the GerA, Ynd, and GerK GRs in moderately HP (mHP; 150 MPa)-induced spore germination. We show that Ynd alone is sufficient for efficient mHP-induced spore germination. GerK also triggers germination with mHP, although at a reduced germination rate compared to that of Ynd. GerA stimulates mHP-induced germination but only in the presence of either the intact GerK or Ynd GR. These results suggests that the effectiveness of the individual GRs in mHP-induced germination differs from their effectiveness in nutrient-induced germination, where GerA plays an essential role. In contrast to Bacillus subtilis spores, treatment with very HP (vHP) of 550 MPa at 37°C did not promote effective germination of B. licheniformis spores. However, treatment with vHP in combination with elevated temperatures (60°C) gave a synergistic effect on spore germination and inactivation. Together, these results provide novel insights into how HP affects B. licheniformis spore germination and inactivation and the role of individual GRs in this process. IMPORTANCE Bacterial spores are inherently resistant to food-processing regimes, such as high-temperature short-time pasteurization, and may therefore compromise food durability and safety. The induction of spore germination facilitates subsequent inactivation by gentler processing conditions that maintain the sensory and nutritional qualities of the food. High-pressure (HP) processing is a nonthermal

Proteomic analysis of lettuce seed germination and thermoinhibition by sampling of individual seeds at germination and removal of storage proteins by polyethylene glycol fractionation.

Science.gov (United States)

Wang, Wei-Qing; Song, Bin-Yan; Deng, Zhi-Jun; Wang, Yue; Liu, Shu-Jun; Møller, Ian Max; Song, Song-Quan

2015-04-01

Germination and thermoinhibition in lettuce (Lactuca sativa 'Jianyexianfeng No. 1') seeds were investigated by a proteomic comparison among dry seeds, germinated seeds at 15°C, at 15°C after imbibition at 25°C for 48 h, or at 25°C in KNO3 (all sampled individually at germination), and ungerminated seeds at 25°C, a thermoinhibitory temperature. Before two-dimensional gel electrophoresis analysis, storage proteins (greater than 50% of total extractable protein) were removed by polyethylene glycol precipitation, which significantly improved the detection of less abundant proteins on two-dimensional gels. A total of 108 protein spots were identified to change more than 2-fold (Pseeds than in ungerminated 25°C seeds. Gene expression of 12 of those proteins correlated well with the protein accumulation. Methionine metabolism, ethylene production, lipid mobilization, cell elongation, and detoxification of aldehydes were revealed to be potentially related to lettuce seed germination and thermoinhibition. Accumulation of three proteins and expression of five genes participating in the mevalonate (MVA) pathway of isoprenoid biosynthesis correlated positively with seed germinability. Inhibition of this pathway by lovastatin delayed seed germination and increased the sensitivity of germination to abscisic acid. MVA pathway-derived products, cytokinins, partially reversed the lovastatin inhibition of germination and released seed thermoinhibition at 25°C. We conclude that the MVA pathway for isoprenoid biosynthesis is involved in lettuce seed germination and thermoinhibition. © 2015 American Society of Plant Biologists. All Rights Reserved.

Low-Temperature Synthesis Routes to Intermetallic Superconductors

Energy Technology Data Exchange (ETDEWEB)

Schaak, Raymond E

2008-01-08

Over the past few years, our group has gained expertise at developing low-temperature solution-based synthetic pathways to complex nanoscale solids, with particular emphasis on nanocrystalline intermetallic compounds. Our synthetic capabilities are providing tools to reproducibly generate intermetallic nanostructures with simultaneous control over crystal structure, composition, and morphology. This DOE-funded project aims to expand these capabilities to intermetallic superconductors. This could represent an important addition to the tools that are available for the synthesis and processing of intermetallic superconductors, which traditionally utilize high-temperature, high-pressure, thin film, or gas-phase vacuum deposition methods. Our current knowledge of intermetallic superconductors suggests that significant enhancements could result from the inherent benefits of low-temperature solution synthesis, e.g. metastable phase formation, control over nanoscale morphology to facilitate size-dependent property studies, robust and inexpensive processability, low-temperature annealing and consolidation, and impurity incorporation (for doping, stoichiometry control, flux pinning, and improving the critical fields). Our focus is on understanding the superconducting properties as a function of synthetic route, crystal structure, crystallite size, and morphology, and developing the synthetic tools necessary to accomplish this. This research program can currently be divided into two classes of superconducting materials: intermetallics (transition metal/post transition metal) and metal carbides/borides. Both involve the development and exploitation of low-temperature synthesis routes followed by detailed characterization of structures and properties, with the goal of understanding how the synthetic pathways influence key superconducting properties of selected target materials. Because of the low-temperature methods used to synthesize them and the nanocrystalline morphologies

Efecto de la temperatura y de la luz sobre la germinación de Nicotiana longiflora Cavaniles y Oenothera indecora Camb. Effect of temperature and the light on germination of Nicotiana longiflora Cavaniles and Oenothera indecora Camb.

Directory of Open Access Journals (Sweden)

D. Faccini

2006-06-01

Full Text Available Nicotiana longiflora y Oenothera indecora son especies de reciente difusión en lotes agrícolas de la región pampeana argentina y se desconocen los factores ambientales que afectan su germinación. El objetivo de este trabajo fue determinar la influencia de la temperatura y de la luz sobre la germinación de ambas especies. Con temperaturas constantes la germinación fue mayor con luz entre los 20 y 35 °C para N. longiflora y entre 10 y 20 °C para O. indecora. Con temperaturas alternadas, N. longiflora presentó mayor germinación en un rango amplio rango con luz, y en oscuridad fue mayor sólo con 10-20 °C. O. indecora germinó sólo con luz en un amplio rango de temperaturas alternadas. La temperatura base en luz y en oscuridad fue de aproximadamente 14 °C para N. longiflora y de aproximadamente 6 °C para O. indecora. A partir de la temperatura base se puede inferir que N. longiflora es una especie con un ciclo de crecimiento primavero-estival y O. indecora otoño-primavero-estival.Nicotiana longiflora and Oenothera indecora are species of recent appearance in croplands in the Argentine humid pampa zone and there is a lack of knowledge about the environmental factors affecting their germination. The temperature and light requirements for germination and the base temperature of both species were determined. Under constant temperatures, germination was higher between 20 and 35 °C for N. longiflora and between 10 and 20 °C for O. indecora. Under fluctuating temperatures, N. longiflora showed higher germination rates in a wide range of temperatures with light. In darkness, germination was higher only between 10-20 °C for N. longiflora, whereas O. indecora germinated only with light, within a wide range of fluctuating temperatures. Base temperature under light and darkness conditions was approximately 14 °C for N. longiflora and approximately 6 °C for O. indecora. Base temperature indicates that N. longiflora is a species with a spring

The pleiotropic effects of the seed germination inhibitor germostatin.

Science.gov (United States)

Ye, Yajin; Zhao, Yang

2016-01-01

Seed dormancy and germination are the most important adaptive traits of seed plants, which control the germination in a proper space and time. Internal genetic factors together with environmental cues govern seed dormancy and germination. Abscisic acid (ABA), a key phytohormone induces seed dormancy and inhibits seed germination through its molecular genetic signaling network responding the seed inherent physiological and environmental factors. Recently, auxin has been shown to be another phytohormone that induces seed dormancy. We have recently shown that germonstatin (GS), a small synthetic molecule identified by high through-put chemical genetic screenings, inhibits seed germination through up-regulating auxin signaling and inducing auxin biosynthesis. GERMOSTATIN RESISTANCE LOCUS 1 (GSR1) encodes a plant homeodomain (PHD) finger protein and is responsible for GS seed germination inhibition. Its knockdown mutant gsr1 displays decreased dormancy. In this report, we show that GS is not an ABA analog and provided 2 other GS-resistant mutants related to the chemical's function in seed germination inhibition other than gsr1, suggesting that GS may have pleiotropic effects through targeting different pathway governing seed germination.

Predicting germination in semi-arid wildland seedbeds II. Field validation of wet thermal-time models

Science.gov (United States)

Jennifer K. Rawlins; Bruce A. Roundy; Dennis Eggett; Nathan. Cline

2011-01-01

Accurate prediction of germination for species used for semi-arid land revegetation would support selection of plant materials for specific climatic conditions and sites. Wet thermal-time models predict germination time by summing progress toward germination subpopulation percentages as a function of temperature across intermittent wet periods or within singular wet...

Determination of Cardinal Temperatures for Cool Season Turfgrass and Two Common Weed Species

Directory of Open Access Journals (Sweden)

Marjan Diayanat

2018-02-01

.27oC; fescue 2.0, 24.86 and 43.48oC ; Prostrate knotweed 2.95, 19.94-22.21 and 44.97oC and annual sowthistle 2.0, 17.77 and 44.86oC, respectively. Conclusions These results show that fescue germinated earliest among the studied species, because it had the lowest base temperature. In comparison to perennial ryegrass, using turfgrass seed with more fescue seed causes sooner turfgrass establishment and less weed competition. Because of their narrow leaves, young seedlings of prostrate knotweed grow upright and appear at first glance to be grass seedlings. With maturity, most plants grow prostrate, especially with traffic or mowing, so mechanical control of this species in turfgrass is impossible andit could be controlled with pre-emergence herbicide. Pre-emergence herbicides are applied prior to the germination of weeds; thus, predication of timing germination help us in decreasing prostrate knotweed competition with turfgrass and its proper management.

Effect of Environmental Factors on Germination and Emergence of Invasive Rumex confertus in Central Europe

Science.gov (United States)

Kołodziejek, Jeremi; Patykowski, Jacek

2015-01-01

Rumex confertus is a biennial species native to Eastern Europe and Asia, where it thrives on meadow-steppes and glades in forest-steppe. This species has increased its range rapidly within central Europe, yet its biology is not well understood, which has led to poorly timed management. Effects of temperature, light, sodium chloride (NaCl), hydrogen ion concentration (pH), potassium nitrate (KNO3), and polyethylene glycol 6000 on seed germination were examined. Seedling emergence was examined for seeds sown at different depths in sand-filled pots. Seeds of R. confertus were nondormant at maturity. The germination percentage and rate of germination were significantly higher in light than in darkness. Secondary dormancy was induced in these seeds by 12 weeks of dark incubation at 4°C. The seeds of R. confertus undergo a seasonal dormancy cycle with deep dormancy in winter and early spring and a low level of dormancy in early autumn. Germination decreased as soil salinity increased. NO3 − increased the percentage and rate of germination in the studied species. Decrease in seedling emergence from the seeds buried at >0.5 cm may be due to deficiency of light. From our experiments, we conclude that the weed R. confertus normally becomes established in vegetation gaps or due to disturbance of the uppermost soil layer during the growing season through the germination of seeds originating from a long-lived seed bank. PMID:26229977

Rice LTG1 is involved in adaptive growth and fitness under low ambient temperature.

Science.gov (United States)

Lu, Guangwen; Wu, Fu-Qing; Wu, Weixun; Wang, Hong-Jun; Zheng, Xiao-Ming; Zhang, Yunhui; Chen, Xiuling; Zhou, Kunneng; Jin, Mingna; Cheng, Zhijun; Li, Xueyong; Jiang, Ling; Wang, Haiyang; Wan, Jianmin

2014-05-01

Low temperature (LT) is one of the most prevalent factors limiting the productivity and geographical distribution of rice (Oryza sativa L.). Although significant progress has been made in elucidating the effect of LT on seed germination and reproductive development in rice, the genetic component affecting vegetative growth under LT remains poorly understood. Here, we report that rice cultivars harboring the dominant LTG1 (Low Temperature Growth 1) allele are more tolerant to LT (15-25°C, a temperature range prevalent in high-altitude, temperate zones and high-latitude areas), than those with the ltg1 allele. Using a map-based cloning strategy, we show that LTG1 encodes a casein kinase I. A functional nucleotide polymorphism was identified in the coding region of LTG1, causing a single amino acid substitution (I357K) that is associated with the growth rate, heading date and yield of rice plants grown at LT. We present evidence that LTG1 affects rice growth at LT via an auxin-dependent process(es). Furthermore, phylogenetic analysis of this locus suggests that the ltg1 haplotype arose before the domestication of rice in tropical climates. Together, our data demonstrate that LTG1 plays an important role in the adaptive growth and fitness of rice cultivars under conditions of low ambient temperature. © 2014 The Authors. The Plant Journal © 2014 John Wiley & Sons Ltd.

Salinity Effects on Germination Properties ofPurslane (Portulaca oleracea L.

Directory of Open Access Journals (Sweden)

m Kafi

2011-02-01

Full Text Available Abstract In order to study seed germination and seedling growth responses of purslane to different levels of salinity, an experiment was conducted in a completely randomized desgin with six levels of salinity (0, 7, 14, 21, 28 and 35 dS/m using NaCl and five replications. Persentage and rate of germination, length and dry weight of radicle and plumule were measured, and ratio radicle to plumule length, mean germination time and seedling vigor index were calculated. The results showed that up to 28 dS/m salinity did not impose any significant different in germination percentage compared with control, but in 35 dS/m salinity it decreased to 19%. germination rate did not show any significant different up to 14 dS/m in comparison with control but beyond this level it significantly decreased with increasing salt stress. Mean germination time up to 21 dS/m did not have significant different in comparison with control, but increased with increasing salinity significantly. Length, fresh and dry weight of radicle and plumule, and seedling vigor index significantly decreased by increasing salinity. Ratio of radicle to plumule length decreased with increasing salt concentration, but there were not significant different among salt levels. According to the results, the germination stage of purslane is remarkably resistant to elevated levels of salinity and it seems that by exerting proper management in farms, it could be established in saline environments. Keywords: Plumule, Radicle, Seedlings of purslane

Salinity on the germination of seed and index of germination speed of three ornamental species

Directory of Open Access Journals (Sweden)

Marcos Vieira Ferraz

2016-09-01

Full Text Available Salinity is a factor that interferes on seed germination in most species. The objective of this work was to study the effects of different concentrations of NaCl on the emergence and vigor of Petunia x hybrida hort. Vilm E. ex., Torenia fournieri Lind and Tagetes patula L. seedlings. The experimental design was entirely randomized with five treatments (five concentrations of NaCl: zero, 25, 50, 75 and 100 mM and four replications of 50 seeds, for each species. The seeds were germinated in germitest paper at the alternating temperature of 20-30°C. Emergence (% and Emergence Rate (ER were performed daily until 14 days. Salt stress caused negative effects on the emergence and vigor on seedlings of these three ornamentals species.

Reduced seed germination in Arabidopsis over-expressing SWI/SNF2 ATPase genes

NARCIS (Netherlands)

Leeggangers, H.A.C.F.; Folta, A.; Muras, A.; Nap, J.P.H.; Mlynarova, L.

2015-01-01

In the life of flowering plants, seed germination is a critical step to ensure survival into the next generation. Generally the seed prior to germination has been in a dormant state with a low rate of metabolism. In the transition from a dormant seed to a germinating seed, various epigenetic

Freezing tolerance of conifer seeds and germinants.

Science.gov (United States)

Hawkins, B J; Guest, H J; Kolotelo, D

2003-12-01

between seedlot hardiness and rate of germination. Germination rate and freezing tolerance of Douglas-fir and western red cedar seedlots was negatively correlated. There was a significant correlation between LT50 after 10 days in the growth chamber and minimum spring temperature at the location of seedlot origin for interior spruce and three seedlots of western red cedar, but no relationship was apparent for lodgepole pine and Douglas-fir.

The plasma membrane proteome of germinating barley embryos

DEFF Research Database (Denmark)

Hynek, Radovan; Svensson, Birte; Jensen, O.N.

2009-01-01

Cereal seed germination involves a complex coordination between different seed tissues. Plasma membranes must play crucial roles in coordination and execution of germination; however, very little is known about seed plasma membrane proteomes due to limited tissue amounts combined...... with amphiphilicity and low abundance of membrane proteins. A fraction enriched in plasma membranes was prepared from embryos dissected from 18 h germinated barley seeds using aqueous two-phase partitioning. Reversed-phase chromatography on C-4 resin performed in micro-spin columns with stepwise elution by 2-propanol...... was used to reduce soluble protein contamination and enrich for hydrophobic proteins. Sixty-one proteins in 14 SDS-PAGE bands were identified by LC-MS/MS and database searches. The identifications provide new insight into the plasma membrane functions in seed germination....

Effect of Salinity and Drought Stresses on Germination Stage and Growth of Black Cumin (Bunium Persicum Boiss

Directory of Open Access Journals (Sweden)

H. R. Saeedi Goraghani

2017-06-01

Full Text Available Introduction Range plants have important and crucial roles in medicinal industry andtogether with scarcity and low quality of the water and soil resources, prevent a quick recovery of the soil plant covering. Because of these restrictions, it is important to consider the use of salt and drought tolerant species for plantation and to preserve plant cover. In this sense, the use of native species such as black cumin (Bunium persicum Boiss may be of interest due to their medicinal characteristics and potential ability to adapt to adverse conditions (dry and saline conditions. Black cumin (B. persicum as a medicinal plant plays a vital role in Iranian medicine so there is a need to know about the factors affecting their growth and propagation. Materials and Methods To investigate the effects of drought and salt stresses on germination and growth in black cumin two separate experiments were conducted. Drought stress was applied through incubation in four different concentrations of PEG 6000 that provide solutions with water potentials ranging from -0.2 to -0.8 MPa (including control and four levels of dryness. Salinity treatments (including control and four levels of salinity were prepared by adding molar concentrations of NaCl to provide a range of salinity from 50 to 300 mM. Germination percentage and speed was calculated by computation of germinated seeds every day. Growth parameters (rootlet, shoot and seedling length total, allometric index and seed vigority were obtained accordingly. Results and Discussion Seeds under both drought and salt stress showed significant reduction in germination percentage, germination rate, radicle length, plumule length, and alometric and seed vigor indices. This trend was much pronounced under high levels of NaCl and low levels of water potentials, so that germination at Ψs = -0.6 MP was completely stopped. Conclusions Assessment of drought and salt stresses on germination and growth in black cumin is very

The effects of Fusarium oxysporum on broomrape (Orobanche egyptiaca) seed germination.

Science.gov (United States)

Hasannejad, S; Zad, S Javad; Alizade, H Mohamad; Rahymian, H

2006-01-01

Broomrape (Orobanche aegyptiaca L.), one of the most important parasitic weeds in Iran, is a root parasitic plant that can attack several crops such as tobacco, sunflower, tomato and etc. Several methods were used for Orobanche control, however these methods are inefficient and very costly. Biological control is an additional recent tool for the control of parasitic weeds. In order to study of the fungus Fusarium oxysporum (biocontrol agent) effects on broomrape seed germination, two laboratory studies were conducted in Tehran University. In the first experiment, different concentration of GR60 (0, 1, 2 and 5 ppm) as stimulation factor for Orobanche seeds germination were experimented. Results showed that concentrations of GR60 had a significant effect on seed germination. The highest seed germination percent was obtained in 1 ppm. In the second experiment, the effect of Fusarium oxysporum was tested on O. aegyptiaca seeds germination. The fungus Fusarium oxysporum were isolated from infested and juvenile O. aegyptiaca ower stalks in tomato field in karaj. Fungus spores suspension in different concentrations (0 (Control), 10(5) (T1), 10(6) (T2), 10(7) (T3) and 3 x 10(7) (T4)) from potato dextrose agar (PDA) prepared and together with 1ppm of GR60 concentration were tested on O. aegyptiaca seeds. Results show that the highest inhibition of seed germination obtained in 10(5) spores/ml. With increasing of suspension concentrations, inhibition percent was reduced and mortality of seeds germ tube was increased. In this investigation, Fusarium oxysporum can be used to inhibit seed germination, stimulate the "suicidal germination" of seeds and reduce the Orobanche seed bank.

Efeito da temperatura de armazenamento e de fitoreguladores na germinação de sementes de maracujá doce e desenvolvimento inicial de mudas = Effect of storage temperature and phytoregulators on germination of sweet passion fruit seeds and seedling development

Directory of Open Access Journals (Sweden)

Marco Eustáquio de Sá

2006-07-01

treatments (without imbibition, distilled water, gibberelin 250 ppm, cytokinin250 ppm and KNO3 0.1% factorial scheme, with four repetitions. The seeds were stored for 20 days, following imbibition for 24 hours. Evaluations were done until 62 days after sowing. Germination percentage, germination speed and seeds initial development were evaluated. The low temperature had positive effect on germination. The gibberelin positively affected the seeds initial development. The gibberelin effect can be perfectly replaced by low temperature of seed storage.

Germination of rye brome (Bromus secalinus L. seeds under simulated drought and different thermal conditions

Directory of Open Access Journals (Sweden)

Małgorzata Haliniarz

2014-01-01

Full Text Available The aim of the present study was to compare the germination of rye brome (Bromus secalinus L. seeds and the initial growth of seedlings under simulated drought and different thermal conditions. The study included two experiments carried out under laboratory conditions in the spring of 2012. The first experiment involved an evaluation of the speed of germination as well as of the biometric characters and weight of seedlings in polyethylene glycol solutions (PEG 8000 in which the water potential was: -0.2; -0.4; -0.65; -0.9 MPa, and in distilled water as the control treatment. The experiment was conducted at the following temperatures: 25/22oC and 18/14oC day/night, at a relative air humidity of 90%. The other experiment, in which lessive soil was used as a germination substrate, was carried out in a plant growth chamber at two levels of air humidity (55–65% and 85–95% and temperature (22/10oC and 16/5oC. The soil moisture content was determined by the gravimetric method and the water potential corresponding to it was as follows: -0.02, -0.07, -0.16, -0.49, -1.55 MPa. The germination capacity and emergence of Bromus secalinus as well as the weight of sprouts produced were significantly dependent on the water potential of the polyethylene glycol solution and on the soil water potential. The emergence of Bromus secalinus was completely inhibited by reducing the soil water potential below -0.16 MPa (the point of strong growth inhibition. The emergence and biometric characters of rye bro- me seedlings were significantly dependent on temperature and air humidity.

Effects of Some Environmental Factors on Seed Germination and Spreading Potentials of Silybum marianum Gaertner

Directory of Open Access Journals (Sweden)

Pasquale Montemurro

2007-09-01

Full Text Available Silybum marianum Gaertner is spreading in many crops of Southern Italy, particularly in durum wheat, sugar beet and some vegetable crops. Information about its biology are useful to set up effective control strategies. Four experiments were carried out at the Crop Science Department of the University of Bari (Southern Italy. Two trials were conducted in Petri dishes and evaluated the effects of different light, temperature and osmotic stress conditions on the seed germination. Another trial evaluated the ability of seedlings to emerge from different depths. The effects of eight different sowing periods on the plant growth were assessed in the fourth experiment. The highest germination rate was found with constant temperatures of 25 °C or 30 °C and with alternating temperatures of 25- 15 °C for 8 and 16 hours respectively. Germination was affected by the light and was significantly decreased at 0.2 Mpa and completely inhibited at -0.8 Mpa. Plant emergence was strongly reduced from a depth of more than 3 cm. The plant size at the first bloom was reduced by postponing the sowing period from October to February. The same decreasing trend was observed in the number of flower heads and in the number of days required for the first bloom. Results can suggest some important strategies to manage this species. False sowing, followed by irrigation, can be recommended in summer, in order to obtain the highest seed germination. Since the emergence of this plant is very scarce from a depth of more than 3 cm, ploughing can be effective to bury seeds in case of strong disseminations in order to reduce the infestation in the following crop.

Herbicide impact on Hormosira banksii gametes measured by fluorescence and germination bioassays

Energy Technology Data Exchange (ETDEWEB)

Seery, Cliff R. [Institute for Water and Environmental Resource Management, Department of Environmental Sciences, University of Technology, Sydney, Westbourne Street, Gore Hill, 2065 NSW (Australia); Gunthorpe, Leanne [Primary Industries Research Victoria (PIRVic), VIC (Australia); Ralph, Peter J. [Institute for Water and Environmental Resource Management, Department of Environmental Sciences, University of Technology, Sydney, Westbourne Street, Gore Hill, 2065 NSW (Australia)]. E-mail: peter.ralph@uts.edu.au

2006-03-15

The innovative bioassay described here involves chlorophyll a fluorescence measurements of gametes from the macroalgae, Hormosira banksii, where gametes (eggs) were exposed to Diuron, Irgarol and Bromacil. Response was assessed as percent inhibition from control of effective quantum yield ({delta}F/Fm') of photosystem II, herein referred to as % PSII Inhibition. This was measured with the dual-channelled pulse amplitude modulated (PAM) fluorometer, ToxY-PAM. The fluorescence bioassay was run simultaneously with an established H. banksii germination bioassay to compare sensitivity, precision, and time-to-result. The fluorescence bioassay gave highly sensitive results evidenced by EC{sub 5}s (% PSII Inhibition) for Diuron, Irgarol and Bromacil being three, four and three orders of magnitude (respectively) lower than EC{sub 5}s generated from the germination bioassays. Precision of the fluorescence bioassay was demonstrated with low coefficient of variations (<30%) for all three toxicants. With regard to time, the fluorescence bioassay gave results within 6 h, as opposed to more than 50 h for the germination bioassay. - Chlorophyll a fluorescence measurements form the basis of a macroalgal bioassay with many advantages over germination-based methods.

Influence of seed size and ecological factors on the germination and emergence of field bindweed (Convolvulus arvensis)

OpenAIRE

Tanveer,A; Tasneem,M; Khaliq,A; Javaid,M.M; Chaudhry,M.N

2013-01-01

An understanding of seed germination ecology of weeds can assist in predicting their potential distribution and developing effective management strategies. Influence of environmental factors and seed size on germination and seedling emergence of Convolvulus arvensis (field bindweed) was studied in laboratory and greenhouse conditions. Germination occurred over a wide range of constant temperatures, between 15 and 40 ºC, with optimum germination between 20 and 25 ºC. Time to start germination,...

Antioxidant activity, total phenolics, flavonoids and antinutritional characteristics of germinated foxtail millet (Setaria italica

Directory of Open Access Journals (Sweden)

Seema Sharma

2015-12-01

Full Text Available A central composite rotatable design was applied to analyse the effects of independent variables [soaking time (ST, germination time (Gt and temperature (GT] on responses [antioxidant activity (AoxA, total phenolic contents (TPC and flavonoid contents (TFC]. The results indicated that with increase in ST, Gt and GT, AoxA, TPC (free/bound and TFC (free/bound of foxtail millet increased significantly. The best combination of germination bioprocess variables for producing optimized germinated foxtail millet flour with the highest AoxA (90.5%, TPC (45.67 mg gallic acid equivalent (GAE/100 g sample and TFC (30.52–43.96 mg RU/g sample were found with soaking time of 15.84 min having germination temperature of 25°C. The optimized germinated foxtail millet flour was nutritionally rich as it produced higher protein (14.32 g/100 g, dietary fibre (27.42 g/100 g, calcium (25.62 mg/kg, iron (54.23 mg/kg, magnesium (107.16 mg/kg and sodium (69.45 mg/kg per kg as compared to un-germinated foxtail millet flour.

Phylogeny, habitat together with biological and ecological factors can influence germination of 36 subalpine Rhododendron species from the eastern Tibetan Plateau.

Science.gov (United States)

Wang, Yongji; Lai, Liming; Du, Hui; Jiang, Lianhe; Wang, Fei; Zhang, Chao; Zhuang, Ping; Zheng, Yuanrun

2018-04-01

The reproductive stages of the life cycle are crucial in explaining the distribution patterns of plant species because of their extreme vulnerability to environmental conditions. Despite reported evidence that seed germination is related to habitat macroclimatic characteristics, such as mean annual temperature, the effect of this trait in controlling plant species distribution has not yet been systematically and quantitatively evaluated. To learn whether seed germination can predict species distribution along altitude gradients, we examined germination data of 36 Rhododendron species in southeastern Tibet originating from contrasting altitudes, habitats, plant heights, seed masses, and phylogenies. Germination varied significantly with altitude, habitat, plant height, and phylogeny and was higher in the light than in the dark. Germination percentage was highest at 10:20°C in the light and 15:25°C in the dark. As altitude increased, germination percentages first rose and then decreased, being highest at 3,500-4,000 m. Germination percentage and rate were highest on rocky slopes, increasing as seed mass and plant height rose. Variations in germination percentage and rate were not significant at subgenera, section, and subsection levels, but they were significant at species level. The results suggested that the relationship between germination and altitude may provide insights into species distribution patterns. Further, germination patterns are a result of long-term evolution as well as taxonomic constraints.

Role of the lens in controlling physical dormancy break and germination of Delonix regia (Fabaceae: Caesalpinioideae).

Science.gov (United States)

Jaganathan, G K; Wu, G-R; Han, Y-Y; Liu, B L

2017-01-01

Physical dormancy occurs in all three subfamilies of Fabaceae, namely Mimosoideae, Papilionoideae and Caesalpinioideae, making it one of the largest plant families in terms of number of species with physical dormancy. However, little is known about the water gap structure and germination ecology of species in Caesalpinioideae. Freshly collected seeds of Delonix regia (Caesalpinioideae) did not imbibe water, thus they had physical dormancy. Both dry heat and wet heat were effective in breaking dormancy, however, longer duration was required at 80 °C and shorter duration at 90 °C. Seeds buried in the field for 2 years germinated to 21% and 42% after the first and second summer, respectively, compared with 3% germination in seeds at the time of maturity. Seeds incubated at 15/60 °C in the laboratory (mimicking summer conditions) for 3 months supported this conclusion, as dormancy was relieved in 18% and 24% of seeds stored dry and watered intermediately, respectively. All the dormancy breaking treatments resulted in lifting of palisade layers in the lens region to form a circular lid-like opening, i.e. water gap (Type II simple). Blocking experiments confirmed that water entered only through the lens and no secondary water entry point was observed. No apparent changes in morphology/anatomy of the hilum region were noted in dormant and non-dormant (water permeable) seeds. These results suggest that summer temperatures could open the lens in a proportion of seeds every year and that germination occurs during the subsequent wet season in the tropics. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

Effect of gaseous ozone for control of stored product pests at low and high temperature

DEFF Research Database (Denmark)

Hansen, Lise Stengård; Hansen, Peer; Vagn Jensen, Karl-Martin

2013-01-01

Gaseous ozone (O3) has shown potential for control of insects in stored grain. A previous laboratory study determined doses of ozone necessary to control freely exposed and internal stages of eleven stored product pest species at 20 C. In this study the impact of temperature on the effect of ozone...... was tested on two species of stored product pests: Sitophilus granarius and Plodia interpunctella. Insects were exposed to continuous flows of ozone in doses of approximately 33 ppm for 6 d or approximately 131 ppm for 8 d at low temperatures between 7.3 and 7.9 C and high temperatures between 29.6 and 31.......6 C, respectively. Results from the previous study conducted at 20 C were used in the data analysis. The result of the treatments was unaffected by the temperatures used in the study. Treatment with a high dose of ozone for 8 d led to full mortality in all stages of S. granarius and all stages of P...

Luz, substrato e temperatura na germinação de sementes de cedro-vermelho Light, substrate and temperature in the germination of seeds of Cedrela odorata

Directory of Open Access Journals (Sweden)

Marco Antônio Amaral Passos

2008-02-01

Full Text Available O objetivo deste estudo foi avaliar o tipo de substrato, a temperatura e os regimes de luz mais adequados à germinação de sementes de Cedrela odorata L. O delineamento experimental adotado, em todos os ensaios, foi o inteiramente casualizado com quatro repetições de 25 sementes cada. As temperaturas constantes de 25 e 30ºC, a temperatura alternada de 20-30ºC e os substratos pó de coco e areia são as melhores condições para a germinação das sementes de C. odorata. A germinação das sementes da espécie estudada não se mostrou sensível aos diferentes regimes de luz aplicados.This work aimed to evaluate the kind of substrate, and temperature and light conditions more suitable for seed germination of Cedrela odorata L. The experimental design adopted in all experiments was the completely randomized design with four repetitions of twenty-five seeds each. The constant temperatures (25 and 30ºC, the alternated temperature (20-30ºC, and the coconut fiber and sand substrates are the better conditions for seed germination of C. odorata. Seed germination of the studied specie showed no sensitiveness to the different levels of light applied.

Characterization of PDF1 and its interaction with DELAY OF GERMINATION1 (DOG1) in the control of seed dormancy in Arabidopsis thaliana

OpenAIRE

Miatton, Emma

2012-01-01

Seed dormancy is defined as the incapacity of a viable seed to germinate under favourable conditions. It is established during seed maturation and reaches high levels in mature dry seeds. Dormancy is a complex adaptive trait that assures germination at proper time of the year at the onset of the favourable growing season. This trait is regulated by hormonal and environmental cues such as temperature and light. In Arabidopsis thaliana dormancy can be released by imbibing seeds at cold temperat...

Seed germination of Pinus koraiensis Siebold and Zucc. in response to light regimes caused by shading and seed positions

Energy Technology Data Exchange (ETDEWEB)

Zhang, M.; Zhu, J.; Yan, Q.

2012-07-01

Pinus koraiensis Siebold and Zucc. (Korean pine), the dominant tree species in the mixed broadleaved Korean pine forests (regional climax), is severely restricted by its regeneration failure. To determine the effects of light regimes on P. koraiensis regeneration, the seed germination process was examined in shade houses and forest stands (before and after leaf expansion) with various light levels created by shading and seed positions. Despite the large size of P. koraiensis seeds (500-600 mg), both light intensity and quality significantly affected the germination percentage in both shade houses and forests. Substantial changes in light intensity and quality led the majority of seeds (80%) to germinate in leafless forests and shade houses, while only a minority ({<=}20%) germinated after leaf expansion in the forests. Moreover, seed germination in shade houses and leafless forests exhibited similar patterns; they consistently reached a 70% shading degree, which was optimal for the seed germination of P. koraiensis on topsoil. Seed positioning significantly affected germination for each shading degree, especially when litter and soil coverings drastically inhibited germination. In conclusion, (1) when seeds were not stressed by temperature and moisture, light irradiance played a critical role in the seed germination of P. koraiensis; (2) seed positioning, in relation to alterations in light intensity and quality, affected the germination of P. koraiensis; (3) a shade house experiment using neutral cloth provided an applicable and controllable way to monitor the P. koraiensis seed germination in early spring before leaf expansion. The light requirement for the germination of P. koraiensis played a key role in the regeneration of P. koraiensis throughout the temperate secondary forests. (Author) 41 refs.

An Endosperm-Associated Cuticle Is Required for Arabidopsis Seed Viability, Dormancy and Early Control of Germination.

Directory of Open Access Journals (Sweden)

Julien De Giorgi

2015-12-01

Full Text Available Cuticular layers and seeds are prominent plant adaptations to terrestrial life that appeared early and late during plant evolution, respectively. The cuticle is a waterproof film covering plant aerial organs preventing excessive water loss and protecting against biotic and abiotic stresses. Cutin, consisting of crosslinked fatty acid monomers, is the most abundant and studied cuticular component. Seeds are dry, metabolically inert structures promoting plant dispersal by keeping the plant embryo in an arrested protected state. In Arabidopsis thaliana seeds, the embryo is surrounded by a single cell endosperm layer itself surrounded by a seed coat layer, the testa. Whole genome analyses lead us to identify cutin biosynthesis genes as regulatory targets of the phytohormones gibberellins (GA and abscisic acid (ABA signaling pathways that control seed germination. Cutin-containing layers are present in seed coats of numerous species, including Arabidopsis, where they regulate permeability to outer compounds. However, the role of cutin in mature seed physiology and germination remains poorly understood. Here we identify in mature seeds a thick cuticular film covering the entire outer surface of the endosperm. This seed cuticle is defective in cutin-deficient bodyguard1 seeds, which is associated with alterations in endospermic permeability. Furthermore, mutants affected in cutin biosynthesis display low seed dormancy and viability levels, which correlates with higher levels of seed lipid oxidative stress. Upon seed imbibition cutin biosynthesis genes are essential to prevent endosperm cellular expansion and testa rupture in response to low GA synthesis. Taken together, our findings suggest that in the course of land plant evolution cuticular structures were co-opted to achieve key physiological seed properties.

Stratification requirements for germination of western larch (Larix occidentalis Nutt.) seed.

Science.gov (United States)

Frank C. Sorenson

1990-01-01

A northeast Washington collection of western larch seeds was stratified for 0,10, 20, 40, and 80 days and incubated at 55, 64, and 73 °F. The germination percentage of filled seeds and speed and uniformity of germination were improved by long stratification, particularly at the lowest incubation temperature. Stratified seeds were also nursery sown in early April and...

Controlled low-temperature fabrication of ZnO nanopillars with a wet-chemical approach

Energy Technology Data Exchange (ETDEWEB)

Postels, B [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Wehmann, H-H [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Bakin, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Kreye, M [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany); Fuhrmann, D [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Blaesing, J [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Hangleiter, A [Institute of Applied Physics, Technical University of Braunschweig, Mendelssohnstrasse 2, D-38106 Braunschweig (Germany); Krost, A [Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Universitaetsplatz 1, 39016 Magdeburg (Germany); Waag, A [Institute of Semiconductor Technology, Technical University of Braunschweig, Hans-Sommer-Strasse 66, D-38106 Braunschweig (Germany)

2007-05-16

Aqueous chemical growth (ACG) is an efficient way to generate wafer-scale and densely packed arrays of ZnO nanopillars on various substrate materials. ACG is a low-temperature growth approach that is only weakly influenced by the substrate and even allows growth on flexible polymer substrates or on conducting materials. The advanced fabrication of wafer-scale and highly vertically aligned arrays of ZnO nanopillars on various substrate materials is demonstrated. Moreover, it is possible to control the morphology in diameter and length by changing the growth conditions. Photoluminescence characterization clearly shows a comparatively strong band-edge luminescence, even at room temperature, that is accompanied by a rather weak visible luminescence in the yellow/orange spectral range.

The impact of germination on the characteristics of brown rice flour and starch.

Science.gov (United States)

Xu, Jie; Zhang, Hui; Guo, Xiaona; Qian, Haifeng

2012-01-30

In recent years, germinated brown rice as a functional food has received great attention with its improved sensory and nutritional properties. Particularly of interest are the high levels of γ-amino butyric acid (GABA) which can be obtained during germination. However, more studies are needed to fully understand the effect of germination on the physicochemical properties of brown rice. Germination altered the chemical composition of brown rice, resulting in an increase in reducing sugar and ash content, and a reduction in amylose. Solubility, paste viscosity, transition temperatures (T(o) , T(p) and T(c) ) and percentage of retrogradation (%Retrogradation) were decreased, while swelling power and turbidity were significantly increased. Scanning electron micrographs indicated that starch granules from germinated brown rice became smaller and less homogeneous. Moreover, germination shortened the chain length of amylopectin and amylose molecules. This investigation provides information on changes in the characteristics of rice flour and rice starch during germination, leading to a better understanding on the chemistry of brown rice germination. Copyright © 2011 Society of Chemical Industry.

Germination in vitro embryo of Walnut (Juglans boliviana

Directory of Open Access Journals (Sweden)

Pérez-Guzmán Jheanete

2015-05-01

Full Text Available Bolivian Juglans is an important forest species found in the rain forests of Bolivia. The seed of this species is recalcitrant with hardened cover, which hinders germination and propagation of the species. The aim of this study was to determine the culture medium for in vitro germination of mature embryos of Bolivian Juglans. Technique initially scarification and disinfection process was determined. Subsequently in vitro culture was performed using the culture medium Woody Plant Medium (WPM with the addition of plant growth regulators (indole butyric acid and 6-benzyl aminopurine in different concentrations. As control WPM, culture medium was used 100%. Response variables evaluated were percentage of contamination and germination; vitroplant length, number of leaves, number of shoots, number of roots per vitroplant, root length and percentage of survival. The plantlets in vitro germination in treatments and the control in the middle l culture WPM supplemented with 0.15 mg / l of IBA and 1.5 mg / l BAP was 90%; other treatments inhibit the growth of the stem and roots of plantlets.

Mutagenic effects of gamma rays on soybean (Glycine max L.) germination and seedlings

Science.gov (United States)

Kusmiyati, F.; Sutarno; Sas, M. G. A.; Herwibawa, B.

2018-01-01

Narrow genetic diversity is a main problem restricting the progress of soybean breeding. One way to improve genetic diversity of plant is through mutation. The purpose of this study was to investigate effect of different dose of gamma rays as induced mutagen on physiological, morphological, and anatomical markers during seed germination and seedling growth of soybean. Seeds of soybean cultivars Dering-1 were irradiated with 11 doses of gamma rays (0, 5, 10, 20, 40, 80, 160, 320, 640, 1280, and 2560 Gy [Gray]. The research design was arranged in a completely randomized block design in three replicates. Results showed that soybean seed exposed at high doses (640, 1280, and 2560 Gy) did not survive more than 20 days, the doses were then removed from anatomical evaluation. Higher doses of gamma rays siginificantly reduced germination percentage at the first count and final count, coefficient of germination velocity, germination rate index, germination index, seedling height and seedling root length, and significantly increased mean germination time, first day of germination, last day of germination, and time spread of germination. However, the effects of gamma rays were varies for density, width, and length of stomata. The LD50 obtained based on survival percentage was 314.78 Gy. It can be concluded that very low and low doses of gamma rays (5-320 Gy) might be used to study the improvement of soybean diversity.

Effects of temperature, light, desiccation and cold storage on ...

African Journals Online (AJOL)

In the present experiments, germination characteristics, desiccation, and low temperature tolerance of seeds of Sophora tonkinensis was studied; a traditional Chinese medicine on the edge of extinction, were investigated for the first time in attempt to interpret their storage behaviour. The results indicate that the temperature ...

Dimorphic cypsela germination and plant growth in Synedrella nodiflora (L. Gaertn. (Asteraceae

Directory of Open Access Journals (Sweden)

PRM Souza Filho

Full Text Available Synedrella nodiflora is a weed species that has dimorphic cypselas: winged peripheral and lanceolate shaped central. The aim of this work is to describe the reproductive capability by measuring dimorphic cypselas morphology, imbibition rates and germinative patterns under temperature, light quality and water availability gradients, and compare the plant growth between two light treatments. The central cypselas were lighter, longer and its pappi were more elongated than the peripheral ones, favoring its dispersion. Neither type had deep dormancy and both of them germinated with the same pattern under the optimum conditions. Both cypselas showed higher germinability in temperatures between 25 and 30 °C, under white light and high water availability, although there are some differences between the types, mainly at dark treatments. Plants grown in direct sunlight accumulated more biomass, allowing for higher plant development and inflorescence production, although shaded light plants capitulum had a higher central: peripheral ratio than the direct sunlight treatment. S. nodiflora cypselas germinate better in unfiltered light places, although the plants are adapted to shady conditions. The species showed high germination potential over a wide range of environmental conditions, as well as fast plant development. All of these features favor distribution in environmental sites.

Performance of seeds Crambe exposed to pre-germination treatments

International Nuclear Information System (INIS)

Rocha Cardoso, Rebeca; Costa Nobre, Danubia Aparecida; Santos de Souza David, Andreia Marcia; Ribeiro Amaro, Hugo Tiago; Borghetti, Renato Antonio; Costa, Marcia Regina

2014-01-01

Encouraging the production and use of biodiesel, seeds of crambe today constitute one of the best options for the supply of raw material, is also an excellent alternative for autumn-winter crop rotation order. The aim of this study was to evaluate the efficiency of combined pre-germination treatments on the seed behavior of Crambe. From a seed sample of FMS Brilhante cultivar, an experimental design completely randomized with a 2 x 5 factorial arrangement was performed. it was formed from combination of two structural conditions, seeds with or without pericarp, and treatments with or without giberelic acid, being: control (no treatment); seeds pre-soaked in distilled water for 24 hours as control; and seeds pre-soaked in gibberellic acid at 4 % at different concentrations (400, 500 and 600 mg.L"-1). Water content, first count germination, germination, seedling emergence and emergence rate index were determined. From these results it is concluded that removal of the pericarp in seed of Crambe, cultivar FMS brilhante, accelerated the germination rate, however, decreased your final percentage. The pre-soaking in gibberellic acid (400, 500 and 600 mg L"-1) for 24 hours, increased the germination and seed vigor crambe with pericarp.

Effect of gamma irradiation on germination and Vitamin-C content of green gram and moth beans

International Nuclear Information System (INIS)

Mohan, Priya; Marathe, S.A.; Rao, V.S.; Bongirwar, D.R.

2001-01-01

Insect disinfestation of prepacked legumes by using low dose gamma irradiation is well known. Changes in sprout length, water uptake and Vitamin C contents of radiation processed legumes were studied. Gamma irradiation (0.25 kGy) of green gram (Phaseolus aureus) and moth bean (Phaseolus aconitifolius) reduced the sprout length on germination by 6-18% at 0.25 kGy and 20-32% at 0.75 kGy, compared to control. Water uptake was not affected in both the legumes by radiation treatment. Vitamin C content increased significantly on germination in both the legumes for 24 and 48 hrs. Further on cooking of the seeds, Vitamin C contents were decreased in both the legumes significantly, more so in pressure cooked and shallow fried samples, compared to boiled (simple cooking). As such radiation treatment did not show any significant change in Vitamin C content of both the legumes either on germination and/or on cooking compared to control. (author)

Selection, assessment of virulence to Alphitobius diaperinus, and Pr1 enzyme production of Beauveria bassiana (Bals. Vuill. isolates cultured at stress temperatures

Directory of Open Access Journals (Sweden)

Kelly Christiane Constanski

2015-12-01

Full Text Available The entomopathogenic fungus Beauveria bassiana is a promising agent for use in insect control. Its pathogenic activity, as well as other factors such as temperature that can interfere with its development, should be assessed, thus, establishing the foundations for B. bassiana use in biological control programs. The objective of this study was to select and induce tolerance of B. bassiana isolates to high and low temperatures and to assess their virulence before and after exposure to those temperatures. A pre-selection test was performed, in which the tolerance of isolates to stress temperatures was tested and compared to the ideal growth temperature of 25 °C for this organism. For the isolates/temperature combinations resulting in growth, conidia germination and colony-forming units (CFUs were assessed. The isolates Unioeste 4 and Unioeste 40 exhibited >95% germinated conidia at 16 and 31 °C. Thereafter, they underwent four consecutive passages at maximum and minimum tolerated temperatures (10 and 37 °C. A significant difference in germination was observed between the two isolates at all temperatures tested. More CFUs were observed for Unioeste 4 compared to Unioeste 40 at all temperatures, and in the case of the latter, there was no difference in CFU formation at 10 and 25 °C. For both isolates, decreased vegetative growth was observed at 37 °C. Recovery of virulence was observed in both isolates, as determined by insect mortality. No relationship was observed between production of the enzyme Pr1 and the virulence of the isolates.

Beneficial Influence of Short-Term Germination on Decreasing Allergenicity of Peanut Proteins.

Science.gov (United States)

Li, Yingchao; Sun, Xiulan; Ma, Zhezhe; Cui, Yan; Du, Chao; Xia, Xiuhua; Qian, He

2016-01-01

Most allergenic storage proteins in peanuts are degraded during seed germination. By altering this natural physiological process, it might be possible to reduce peanut protein allergenicity. However, little is known about the change in allergenic proteins and their corresponding immunocreactivity, and the effects of major environmental conditions on their allergenicity during germination. In this study, the influence of different germination conditions (temperature and light) on the degradation of Ara h1 and allergenicity changes of peanut seeds was evaluated by ELISA and Western blotting. The results showed that the 40- and 65-kDa proteins in peanut seeds degraded rapidly during the time course, beginning at 60 (at 25 °C) and 108 h (at 20 °C), and the corresponding immunocreactivity of Ara h1 decreased approximately one-third after 5 to 7 d of germination. Compared with the cotyledons, the embryonic axes had a higher proportion of Ara h1, which was then degraded relatively faster during germination, resulting in a significant reduction in its allergenicity. Although a higher temperature improved the seed germination rate, it affected sprout quality (as did light); therefore, 25 °C and dark surroundings were suitable conditions under which peanut sprouts were processed; neither factor significantly affected the allergenicity of Ara h1. These results provided a theoretical basis for studies using biological methods to reduce peanut allergenicity. © 2015 Institute of Food Technologists®

Temperature-controlled irrigated tip radiofrequency catheter ablation

DEFF Research Database (Denmark)

Petersen, H H; Chen, X; Pietersen, Adrian

1998-01-01

INTRODUCTION: In patients with ventricular tachycardias due to structural heart disease, catheter ablation cures radiofrequency ablation. Irrigated tip radiofrequency ablation using power control and high infusion rates enlarges lesion......: We conclude that temperature-controlled radiofrequency ablation with irrigated tip catheters using low target temperature and low infusion rate enlarges lesion size without increasing the incidence of cratering and reduces coagulum formation of the tip....

In vitro germination and viability of pollen grain of coconut accessions1

Directory of Open Access Journals (Sweden)

Catrine Regina Feitosa Moura

Full Text Available Storage as a means of maintaining the pollen viability is important for the preservation of the genetic variability, facilitates the exchange of germplasm and greatly contributes to the generation of variability obtained from artificial crosses, increasing the efficiency of breeding programs. The objective of this study was to select different culture media for the in vitro germination of pollen grain of dwarf and tall coconut accessions, as well as to determine the viability of pollen grain at room temperature conditions. For this purpose, Brazil Green Dwarf (BGD and Brazilian Tall (BRA pollen grains derived from the Coconut Active Germplasm Bank of Embrapa Coastal Tablelands Sergipe were used. To evaluate the effect of different culture media on the in vitro germination of pollen grains of anão verde do Brasil de Jiqui (AVeBrJ and gigante do Brasil Praia do Forte (GBrPF accessions, they were inoculated on to Petri dishes containing 2 ml of culture media. The pollen viability was assessed by staining with 1% acetic carmine and in vitro germination at 0, 24, 48 and 72 hours. The culture medium of Lora is suitable to assess the in vitrogermination of pollen grain of the AVeBrJ and GBrPF accessions. The pollen grain of the AVeBrJ accession showed intermediate viability (66.87% at room temperature up to 23.14 hours by in vitro germination. The pollen grain of the GBrPF accession showed high viability, above 70%, at room temperature up to 120 hours by in vitro germination.

Design of Water Temperature Control System Based on Single Chip Microcomputer

Science.gov (United States)

Tan, Hanhong; Yan, Qiyan

2017-12-01

In this paper, we mainly introduce a multi-function water temperature controller designed with 51 single-chip microcomputer. This controller has automatic and manual water, set the water temperature, real-time display of water and temperature and alarm function, and has a simple structure, high reliability, low cost. The current water temperature controller on the market basically use bimetal temperature control, temperature control accuracy is low, poor reliability, a single function. With the development of microelectronics technology, monolithic microprocessor function is increasing, the price is low, in all aspects of widely used. In the water temperature controller in the application of single-chip, with a simple design, high reliability, easy to expand the advantages of the function. Is based on the appeal background, so this paper focuses on the temperature controller in the intelligent control of the discussion.

Preparation and Low Temperature Short-term Storage for Synthetic Seeds of Caladium bicolor

Directory of Open Access Journals (Sweden)

Mehpara MAQSOOD

2015-03-01

Full Text Available An efficient somatic embryo encapsulation and in vitro plant regeneration technique were established with Caladium bicolor, an important ornamental plant.Tuber derived embryogenic callus (95.50% was obtained on Murashige and Skoog (MS medium amended with 0.5 mg L-1 α-Naphthalene acetic acid (NAA + 0.5 mg L-1 6-Benzyladenine (BA. The embryogenic callus later differentiated into somatic embryos in the same plant growth regulators (PGRs added medium (NAA and BA. The induced embryos matured and developed into plantlets in NAA and BA added media; maximum plantlets development was observed at 1.0 mg L-1 NAA + 1.0 mg L-1 BA supplemented medium. Synthetic seeds were produced by encapsulating embryos in gel containing 3.0% sucrose + 3.0% sodium alginate and 100 mM of calcium chloride.The highest synthetic seed germination (97.6% was observed on medium supplemented with 1.0 mg L-1 NAA + 1.0 mg L-1 BA. The synthetic seeds were kept at low temperatures for storage; the encapsulated beads were viable and demonstrated good germination even after 12 weeks of storage at 4 °C. The plantlet recovery frequency was however declined with time. The synthetic seed derived plantlets were morphologically similar to the mother plant.

Planteose as a storage carbohydrate required for early stage of germination of Orobanche minor and its metabolism as a possible target for selective control

Science.gov (United States)

Wakabayashi, Takatoshi; Joseph, Benesh; Yasumoto, Shuhei; Akashi, Tomoyoshi; Aoki, Toshio; Harada, Kazuo; Muranaka, Satoru; Bamba, Takeshi; Fukusaki, Eiichiro; Takeuchi, Yasutomo; Yoneyama, Koichi; Muranaka, Toshiya; Sugimoto, Yukihiro; Okazawa, Atsushi

2015-01-01

Root parasitic weeds in Orobanchaceae cause serious damage to worldwide agriculture. Germination of the parasites requires host-derived germination stimulants, such as strigolactones, as indicators of host roots within reach of the parasite’s radicles. This unique germination process was focused on to identify metabolic pathways required for germination, and to design a selective control strategy. A metabolomic analysis of germinating seeds of clover broomrape, Orobanche minor, was conducted to identify its distinctive metabolites. Consequently, a galactosyl-sucrose trisaccharide, planteose (α-d-galactopyranosyl-(1→6)-β-d-fructofuranosyl-(2→1)-α-d-glucopyranoside), was identified as a metabolite that decreased promptly after reception of the germination stimulant. To investigate the importance of planteose metabolism, the effects of several glycosidase inhibitors were examined, and nojirimycin bisulfite (NJ) was found to alter the sugar metabolism and to selectively inhibit the germination of O. minor. Planteose consumption was similar in NJ-treated seeds and non-treated germinating seeds; however, NJ-treated seeds showed lower consumption of sucrose, a possible intermediate of planteose metabolism, resulting in significantly less glucose and fructose. This inhibitory effect was recovered by adding glucose. These results suggest that planteose is a storage carbohydrate required for early stage of germination of O. minor, and NJ inhibits germination by blocking the supply of essential glucose from planteose and sucrose. Additionally, NJ selectively inhibited radicle elongation of germinated seeds of Orobanchaceae plants (Striga hermonthica and Phtheirospermum japonicum). Thus, NJ will be a promising tool to develop specific herbicides to the parasites, especially broomrapes, and to improve our understanding of the molecular mechanisms of this unique germination. PMID:25821071

Perceived air quality, thermal comfort, and SBS symptoms at low air temperature and increased radiant temperature

DEFF Research Database (Denmark)

Toftum, Jørn; Reimann, Gregers Peter; Foldbjerg, P.

2002-01-01

source present at the low temperature. To maintain overall thermal neutrality, the low air temperature was partly compensated for by individually controlled radiant heating, and partly by allowing subjects to modify clothing insulation. A reduction of the air temperature from 23 deg.C to 18 deg.......C suggested an improvement of the perceived air quality, while no systematic effect on symptom intensity was observed. The overall indoor environment was evaluated equally acceptable at both temperatures due to local thermal discomfort at the low air temperature....

The proceedings of 1993-workshop on 'development and application of facilities for low temperature irradiation as well as controlled irradiation'

International Nuclear Information System (INIS)

Kuramoto, Eiichi; Okada, Moritami

1993-03-01

This is the proceedings of 1992-workshop of the working group on 'Development and Application of Facilities for Low Temperature Irradiation as well as Controlled Irradiation' held at the Research Reactor Institute of Kyoto University on February 23 and 24, 1993. In this workshop until now, studies on irradiation effects in many materials irradiated at lower and higher temperatures have been reported. It has been clearly defined that a careful choice of irradiation conditions is most important. At the present time, a setting plan of exactly controlled irradiation facility, which is able to irradiate with higher temperatures, is in progress. On the other hand, a plan of vertical low temperature irradiation facility has not yet been performed for lack of funds. In last year, a middle scale plan of low temperature irradiation facility, which is possible to irradiate a fast-neutron dose above 10 17 n/cm 2 at about 5K, was proposed in this workshop. In this proceedings, the advanced facility is required to construct to the KUR as soon as possible by many of the workshop members. (author)

Early establishment of trees at the alpine treeline: idiosyncratic species responses to temperature-moisture interactions.

Science.gov (United States)

Loranger, Hannah; Zotz, Gerhard; Bader, Maaike Y

2016-01-01

On a global scale, temperature is the main determinant of arctic and alpine treeline position. However on a local scale, treeline form and position vary considerably due to other climatic factors, tree species ecology and life-stage-dependent responses. For treelines to advance poleward or uphill, the first steps are germination and seedling establishment. These earliest life stages may be major bottlenecks for treeline tree populations and will depend differently on climatic conditions than adult trees. We investigated the effect of soil temperature and moisture on germination and early seedling survival in a field experiment in the French Alps near the local treeline (2100 m a.s.l.) using passive temperature manipulations and two watering regimes. Five European treeline tree species were studied: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata and Sorbus aucuparia In addition, we monitored the germination response of three of these species to low temperatures under controlled conditions in growth chambers. The early establishment of these trees at the alpine treeline was limited either by temperature or by moisture, the sensitivity to one factor often depending on the intensity of the other. The results showed that the relative importance of the two factors and the direction of the effects are highly species-specific, while both factors tend to have consistent effects on both germination and early seedling survival within each species. We show that temperature and water availability are both important contributors to establishment patterns of treeline trees and hence to species-specific forms and positions of alpine treelines. The observed idiosyncratic species responses highlight the need for studies including several species and life-stages to create predictive power concerning future treeline dynamics. © The Authors 2016. Published by Oxford University Press on behalf of the Annals of Botany Company.

Pre-germination treatments for Hymenaea stigonocarpa Mart. ex Hayne seeds

Directory of Open Access Journals (Sweden)

Sérgio Roberto Garcia dos Santos

2016-12-01

Full Text Available Hymenaea stigonocarpa, known as Jatoba-do-cerrado, belongs to the family Fabaceae (Leguminosae and is included in the category "near threatened with extinction." It occurs in cerrado and cerradão areas, and its seeds have physical dormancy. Because of this characteristic, the aim of this study was to evaluate different pre-germination treatments and control in H. stigonocarpa seeds, namely: immersion in fire, sulfuric acid, hydrochloric acid, acetone, ether and hot water (100°C, and mechanical scarification of the seed coat by roughing with sandpaper or cutting with nail clippers and washing in running water for 2 hours. The parameters analyzed were percentage of germination, germination speed index (GSI and the percentage of hard and firm seeds and dead seeds. The final results were: a germination: boiling water and sulfuric acid were superior to the control; b GSI: boiling water, sulfuric acid, fire and sandpaper were superior to the control and c percentage of dead seeds was not statistically different between the different treatments and control. In conclusion, boiling water and sulfuric acid, were the best treatments, with regard to the parameters examined.

Spore germination of Gleichenella pectinata (Willd. Ching (Polypodiopsida-Gleicheniaceae at different temperatures, levels of light and pH

Directory of Open Access Journals (Sweden)

Eunice Pereira Gonçalves dos Santos

2010-12-01

Full Text Available This study investigated the effects of different temperatures (25 and 30 ± 2 ºC, light levels (62, 42, 22 and 5% of natural light, and pH (4.0, 4.5, 5.0, 5.5, 6.0 and 6.7 on the spore germination of Gleichenella pectinata. To accomplish this, the spores were surface sterilized and sown in bottles containing mineral medium. The spores of G. pectinata are monolets and the perispore surface can show large and irregular deposits. During germination, filamentous gametophytes with and without developing rhizoids were observed. Only gametophytes which presented developed rhizoids were able to reach the heart-shaped developmental stage. Based on the collection, the rate of and gametophyte development were generally very low. The relative germination rates were higher at 25 ºC than at 30 °C. Moreover, the highest percentages of gametophytes with developed rhizoids were observed at 22 and 5% of natural light (8.8 ± 2.3% and 11.3 ± 2.2% respectively and the highest percentage of heart-shaped gametophytes were observed at pH 4.5 and 5.0 (1.2 ± 0.8% and 2.2 ± 0.8%, respectively.A finalidade deste estudo foi analisar o potencial germinativo dos esporos de G. pectinata e verificar os efeitos de níveis de luz (62, 42, 22 e 5% da luz natural, das temperaturas de 25 e 30 ºC e de pHs entre 4,0 e 6,7 na germinação. Esporos de G. pectinata são monoletes e a superfície apresenta depósitos grandes e irregulares. Observamos três classes de desenvolvimento: esporos contendo cloroplastos, gametófitos filamentosos sem rizóides desenvolvidos e gametófitos filamentosos com rizóides desenvolvidos. Somente os gametófitos com rizóides desenvolvidos foram capazes de alcançar a fase cordiforme. As porcentagens de germinação foram mais elevadas à temperatura de 25ºC do que 30 ºC. As mais elevadas porcentagens de gametófitos com rizóides desenvolvidos foram observadas sob 22 e 5% da luz natural e as porcentagens mais elevadas de gamet

Decreased TK activity alters growth, yield and tolerance to low temperature and low light intensity in transgenic cucumber plants.

Science.gov (United States)

Bi, Huangai; Dong, Xubing; Wu, Guoxiu; Wang, Meiling; Ai, Xizhen

2015-02-01

Four CsTK antisense transgenic cucumber plants were obtained. Decreased TK activity decreased the photosynthetic rate, seed germination rate, growth yield, and the tolerance to low temperature and weak light stress. Transketolase (TK, EC 2.2.1.1) is a key enzyme in the photosynthetic carbon reduction cycle (Calvin cycle). A cDNA fragment (526 bp) encoding transketolase was cloned from cucumber plants (Cucumis sativa L. cv 'Jinyou 3') by RT-PCR. The antisense expression [(PBI-CsTK(-)] vector containing the CsTK gene fragment was constructed. The resulting plasmid was introduced into the cucumber inbred lines '08-1' using the agrobacterium-mediated method, and four antisense transgenic cucumber plants were obtained. Decreased CsTK expression either unaltered or slightly increased the mRNA abundance and activities of the other main enzymes in the Calvin cycle, however, it decreased the TK activity and net photosynthetic rate (Pn) in antisense transgenic cucumber leaves. Antisense plants showed decreases in the growth, ratio of female flowers and yield compared with the wild-type (WT) plants. The decrease in Pn, stomatal conductance (Gs), transpiration rate (Tr), photochemical efficiency (Fv/Fm) and actual photochemical efficiency of PSII (ΦPSII) and the increase in electrolyte leakage (EL) were greater in antisense transgenic plants than in WT plants under low temperature (5 °C) and low light intensity (100 μmol m(-2) s(-1)).

Germination phenology determines the propensity for facilitation and competition.

Science.gov (United States)

Leverett, Lindsay D

2017-09-01

A single plant can interact both positively and negatively with its neighbors through the processes of facilitation and competition, respectively. Much of the variation in the balance of facilitation and competition that individuals experience can be explained by the degree of physical stress and the sizes or ages of plants during the interaction. Germination phenology partly controls both of these factors, but its role in defining the facilitation-competition balance has not been explicitly considered. I performed an experiment in a population of the winter annual Arabidopsis thaliana (Brassicaceae) to test whether germinating during physically stressful periods leads to facilitation while germinating during periods that promote growth and reproduction leads to competition. I manipulated germination and neighbor presence across two years in order to quantify the effects of the local plant community on survival, fecundity, and total fitness as a function of germination phenology. Neighbors increased survival when germination occurred under conditions that were unsuitable for survival, but they reduced fecundity in germinants that were otherwise the most fecund. Later germination was associated with facilitation in the first year but competition in the second year. These episodes of facilitation and competition opposed each other, leading to no net effect of neighbors when averaged over all cohorts. These results indicate that variation in germination timing can explain some of the variation in the facilitation-competition balance in plant communities. © 2017 by the Ecological Society of America.