Full Text Available Agriophyllum squarrosum (L Moq. is medicine herb used as a traditional Mongolian drug. Its pharmacological effi cacy studies are rarely reported. In the present study, we tested and confi rmed the antihyperlipidaemic activity of A. squarrosum and its extracts in rats for the fi rst time. The results of the antihyperlipidaemic experiment in vivo showed that A. squarrosum and its extracts had signifi cant lipid-lowering activities. The signifi cances of A. squarrosum and its extracts on decreasing blood levels of total cholesterol, triglyceride, and low density lipoprotein cholesterol were equal to that of simvastatin, which is a drug for the treatment of hyperlipidaemic.
Genievskaya, Yuliya; Abugalieva, Saule; Zhubanysheva, Aibatsha; Turuspekov, Yerlan
Sand rice (Agriophyllum squarrosum (L.) Moq.) is an annual shrub-like plant adapted to the mobile sand dunes in desert and semi-desert regions of Asia. It has a balanced nutrient composition with relatively high concentration of lipids and proteins, which results in its nutrition being similar to legumes. Sand rice's proteins contain the full range of essential amino acids. However, calories content is more similar to wheat. These features together with desert stress resistance make sand rice a potential food crop resilient to ongoing climate change. It is also an important fodder crop (on young stages of growth) for cattle in arid regions of Kazakhstan. In our work, sand rice samples were collected from two distant regions of Kazakhstan as a part of the nation-wide project to determine genetic variation of the native flora. Samples were collected in western and southeastern parts of Kazakhstan separated by distances of up to 1300 km. Sequences of the nuclear ribosomal DNA ITS1-5.8S-ITS2 region and the chloroplast matK gene confirmed the identity of species defined by morphological traits. Comparison with GenBank sequences revealed polymorphic sequence positions among Kazakh populations and GenBank references, and suggested a distinction among local populations of sand rice. The phylogenetic analysis of nucleotide sequences showed a clear partition of A. squarrosum (L.) Moq. from Agriophyllum minus Fisch. & C.A. Mey, which grows in the same sand dunes environment. DNA barcoding analyses of ITS and matK sequences showed a segregation of A. squarrosum from A. minus into separate clades in Maximum-Likelhood dendrograms. ITS analysis can be successfully used to characterize A. squarrosum populations growing quite distant from each other. The data obtained in this work provide the basis for further investigations on A. squarrosum population structure and may play a role in the screening of sand rice plants growing in desert and semi-desert environments of Central Asia
Qian, Chaoju; Yin, Hengxia; Shi, Yong; Zhao, Jiecai; Yin, Chengliang; Luo, Wanyin; Dong, Zhibao; Chen, Guoxiong; Yan, Xia; Wang, Xiao-Ru; Ma, Xiao-Fei
Climate change plays an important role in the transition of ecosystems. Stratigraphic investigations have suggested that the Asian interior experienced frequent transitions between grassland and desert ecosystems as a consequence of global climate change. Using maternally and bi-parentally inherited markers, we investigated the population dynamics of Agriophyllum squarrosum (Chenopodiaceae), an annual pioneer plant endemic to mobile sand dunes. Phylogeographic analysis revealed that A. squarrosum could originate from Gurbantunggut desert since ~1.6 Ma, and subsequently underwent three waves of colonisation into other deserts and sandy lands corresponding to several glaciations. The rapid population expansion and distribution range shifts of A. squarrosum from monsoonal climate zones suggested that the development of the monsoonal climate significantly enhanced the population growth and gene flow of A. squarrosum. These data also suggested that desertification of the fragile grassland ecosystems in the Qinghai-Tibetan Plateau was more ancient than previously suggested and will be aggravated under global warming in the future. This study provides new molecular phylogeographic insights into how pioneer annual plant species in desert ecosystems respond to global climate change, and facilitates evaluation of the ecological potential and genetic resources of future crops for non-arable dry lands to mitigate climate change.
Zhao, Ha-Lin; Qu, Hao; Zhou, Rui-Lian; Wang, Jin; Li, Jin; Yun, Jian-Ying
In 2010-2011, a sand burial experiment was conducted on the Horqin Sand Land of Inner Mongolia to study the growth characteristics and physiological properties of Agriophyllum squarrosum seedlings under different depths of sand burial. The A. squarrosum seedlings had stronger tolerance against sand burial. The seedling growth could be severely inhibited when the burial depth exceeded seedling height, but some seedlings could still be survived when the burial depth exceeded 1.66 times of seedling height. When the burial depth did not exceed the seedling height, the seedling MDA content and membrane permeability had no significant change, but the lipid peroxidation was aggravated and the cell membrane was damaged with increasing burial depth. Under sand burial stress, the seedling SOD and POD activities and proline content increased significantly, while the seedling CAT activity and soluble sugar content deceased. Sand burial decreased the leaf photosynthetic area and damaged cell membrane, inducing the increase of seedling mortality and the inhibition of seedling growth. The increase of SOD and POD activities and proline content played a definite role in reducing the sand burial damage to A. squarrosum seedlings.
Corispermum macrocarpum, Setaria viridis and Agriophyllum squarrosum are dominant psammophytes with strong environmental adaptability in Horqin Sandy Land, a typical agro-pastoral ecotone with frequent and intense sand activity in Northern China. We studied the survival rates, activity of antioxidant enzyme ...
Saxena, Anuj; Saxena, Anjali
Physiological and biochemical responses, metal bioaccumulation and tolerance potential of Sphagnum squarrosum Crome Samml. to Cu and Cd were studied to determine its bioindication and bioremediation potential. Results suggest that glutathione treatment increases the metal accumulation potential and plays a definite role in heavy metal scavenging. High abundance of Sphagnum in metal-rich sites strongly suggests its high metal tolerance capabilities. This experiment demonstrates that S. squarrosum is able to accumulate and tolerate a high amount of metals and feasibility of its application as bioindicator and remediator test species of metal-contaminated environment.
Szövényi, Péter; Hock, Zsófia; Urmi, Edwin; Schneller, Jakob J
The chloroplast phylogeography of two peat mosses (Sphagnum fimbriatum and Sphagnum squarrosum) with similar distributions but different life history characteristics was investigated in Europe. Our main aim was to test whether similar distributions reflect similar phylogeographic and phylodemographic processes. Accessions covering the European distributions of the species were collected and approx. 2000 bp of the chloroplast genome of each species was sequenced. Maximum parsimony, statistical parsimony and phylodemographic analyses were used to address the question of whether these species with similar distributions show evidence of similar phylogeographic and phylodemographic processes. The chloroplast haplotypes of the currently spreading species S. fimbriatum showed strong geographic structure, whereas those of S. squarrosum, which has stable historical population sizes, showed only very weak geographic affinity and were widely distributed. We hypothesize that S. fimbriatum survived the last glaciations along the Atlantic coast of Europe, whereas S. squarrosum had numerous, scattered refugia in Europe. The dominance of one haplotype of S. fimbriatum across almost all of Europe suggests rapid colonization after the last glacial maximum. We hypothesize that high colonizing ability is an inherent characteristic of the species and its recent expansion in Europe is a response to climate change.
Present study was undertaken as an attempt to study the effect of pollutants on biological responses of Sphagnum growing at Kainchi, Kumaon hills (Uttranchal). Sphagnum plants of almost identical size, collected from the marked sites of Kainchi in different seasons viz., monsoon, winter, summer and again in monsoon, were analysed for chlorophyll, protein, shoot length and nitrate reductase and peroxidase activities. Maximum chlorophyll, protein, shoots length and nitrate reductase activities were observed during the monsoon while minimum in summers. The abundance of Sphagnum and two other bryophytes, Marchantia and Plagiochasma was also higher in monsoon than in other seasons. The study also indicated that Sphagnum has more bioaccumulation and tolerance potential for heavy metals than Marchantia and Plagiochasma.
Gao, Ruiru; Yang, Xuejun; Yang, Fan; Wei, Lingling; Huang, Zhenying; Walck, Jeffrey L
Simultaneous formation of aerial and soil seed banks by a species provides a mechanism for population maintenance in unpredictable environments. Eolian activity greatly affects growth and regeneration of plants in a sand dune system, but we know little about the difference in the contributions of these two seed banks to population dynamics in sand dunes. Seed release, germination, seedling emergence and survival of a desert annual, Agriophyllum squarrosum (Chenopodiaceae), inhabiting the Ordos Sandland in China, were determined in order to explore the different functions of the aerial and soil seed banks. The size of the aerial seed bank was higher than that of the soil seed bank throughout the growing season. Seed release was positively related to wind velocity. Compared with the soil seed bank, seed germination from the aerial seed bank was lower at low temperature (5/15 °C night/day) but higher in the light. Seedling emergence from the soil seed bank was earlier than that from the aerial seed bank. Early-emerged (15 April-15 May) seedlings died due to frost, but seedlings that emerged during the following months survived to reproduce successfully. The timing of seed release and different germination behaviour resulted in a temporal heterogeneity of seedling emergence and establishment between the two seed banks. The study suggests that a bet-hedging strategy for the two seed banks enables A. squarrosum populations to cope successfully with the unpredictable desert environment. © The Author 2014. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: firstname.lastname@example.org.
Lan, Shubin; Zhang, Qingyi; Wu, Li; Liu, Yongding; Zhang, Delu; Hu, Chunxiang
Desertification has been recognized as a global environmental problem, and one region experiencing ongoing desertification is the eastern edge of Qubqi Desert (Inner Mongolia). To investigate the facilitating effects of cyanobacterial inoculation technology on the desertification control along this steppe-desert transition region, artificial cyanobacterial crusts were constructed with two filamentous cyanobacteria 3 and 8 years ago combined with Salix planting. The results showed that no crusts formed after 3 years of fixation only with Salix planting, whereas after cyanobacterial inoculation, the crusts formed quickly and gradually succeed to moss crusts. During that course, topsoil environments were gradually improved, providing the necessary material basis for the regeneration of vascular plants. In this investigation, total 27 species of vascular plants had regenerated in the experimental region, mainly belonging to Asteraceae, Poaceae, Chenopodiaceae and Leguminosae. Using space time substitution, the dominant species along with the application of cyanobacterial inoculation technology succeeded from Agriophyllum squarrosum ultimately to Leymus chinensis. In addition, it was found that the shady side of the dunes is more conducive to crust development and succession of vegetation communities. Conclusively, our results indicate artificial cyanobacterial inoculation technology is an effective and desirable path for desertification control.
Coastal Sand Dune flora (CSD) forms a specialized group of plants commonly referred as psammophytes. Goa has limited natural resources including beaches and sand dunes. The state is globally known for its tourism activities, which pressurize...
Y. Wang; B. C. Alberto; D. Jiang; M. Ala; X. Li; Q. Zhou; J. Lin; G. Ren; L. Jia
Artemisia wudanica is an endemic, perennial, pioneering psammophyte species in the sand dune ecosystems of western Horqin Sand Land in northern China. However, no studies have addressed how sexual and asexual reproduction modes of A. wudanica perform at the transitional zones between active dune inter-dune lowlands and active dunes. In early spring, quadrats were randomly set up in the study area to monitor surviving seedling and/or ramet density and frequency coming from se...
He, M. Z.
Aims Biological soil crusts (BSCs) are a key biotic component of desert ecosystems worldwide. However, most studies carried out to date on carbon (fluxes) in these ecosystems, such as soil respiration (RS), have neglected them. Also, winter RS is reported to be a significant component of annual carbon budget in other ecosystems, however, we have less knowledge about winter RS of BSCs in winter and its contribution to carbon cycle in desert regions. Therefore, the specific objectives of this study were to: (i) quantify the effects of different BSCs types (moss crust, algae crust, physical crust) on the winter RS; (ii) explore relationships of RS against soil temperature and water content for different BSCs, and (iii) assess the relative contribution of BSCs to the annual amount of C released by RS at desert ecosystem level. Methods Site Description The study sites are located at the southeast fringe of the Tengger Desert in the Shapotou region of the Ningxia Hui Autonomous Region [37°32'N and 105°02'E, at 1340 m above mean sea level (a.m.s.l.)], western China. The mean daily temperature in January is -6.9°C , while it is 24.3°C in July. The mean annual precipitation is 186 mm, approximately 80% of which falls between May and September. The annual potential evaporation is 2800 mm. The landscape of the Shapotou region is characterized by large and dense reticulate barchans chains of sand dunes that migrate south-eastward at a velocity of 3-6 m per year. The soil is loose, infertile and mobile and can thus be classified as orthic sierozem and Aeolian sandy soil. Additionally, the soil has a consistent gravimetric water content that ranges from 3 to 4%. The groundwater in the study area is too deep (>60 m) to support large areas of the native vegetation cover; therefore, precipitation is usually the only source of freshwater. The predominant native plants are Hedysarum scoparium Fisch. and Agriophyllum squarrosum Moq., Psammochloa cillosa Bor, which scattered
Liliane Henriques Fernandes
Full Text Available The objectives of this work were to evaluate the richness and diversity of the Poduromorpha fauna in two biotopes in Restinga de Maricá, RJ, Brazil, to identify the characteristic species of each biotope and to determine the relationships between the community structure and the abiotic environmental parameters. Representatives of the Poduromorpha (Collembola order were studied under an ecological viewpoint in halophyte-psammophyte vegetation and foredune zone in preserved areas of Restinga de Maricá, a sand dune environment in the state of Rio de Janeiro, Brazil. The foredune zone showed the highest diversity, richness and equitability of springtail species. Differences in the fundamental, accessory and accidental species in each environment were encountered. Paraxenylla piloua was found to be an indicator species of the halophyte-psammophyte vegetation, while Friesea reducta, Pseudachorutes difficilis and Xenylla maritima were indicators of the foredune zone. The canonical correspondence analysis indicated pH, organic matter content and soil humidity as the most important factors influencing the spatiotemporal distribution of the species.Os objetivos deste trabalho foram avaliar a riqueza e a diversidade da fauna de Poduromorpha em dois biótopos na Restinga de Maricá, RJ, identificar as espécies características de cada biótopo e determinar as relações da estrutura da comunidade com parâmetros ambientais abióticos. Representantes da ordem Poduromorpha (Collembola foram estudados do ponto de vista ecológico nos ambientes de vegetação halófila-psamófila reptante e de primeiro cordão arenoso em áreas preservadas da Restinga de Maricá, localizada no Estado do Rio de Janeiro, Brasil. Os maiores valores de diversidade, riqueza e equitabilidade de espécies de colêmbolos foram observados no ambiente de primeiro cordão arenoso. Foram encontradas diferenças nas espécies fundamentais, acessórias e acidentais nos ambientes
Zhu, Yajuan; Dong, Ming; Huang, Zhenying
Sand dune plants possess many adaptation strategies to withstand sand environment, e. g., some desert plant seeds are dormant when matured, which helps them to escape from unfeasible environment conditions and be preserved as seed bank. The seed germination and seedling establishment of psammophytes need moderate sand burial, while excessive burial will inhibit seed germination and seedling emergence. Seeds without germination in deeper sand are in enforced dormancy, and form soil seed bank. Sand dune plant seedlings could tolerant finite sand burial by increasing the number of nodes per culm and elongating internodes. When the seedlings are partially buried, they could survive through the maintenance of photosynthesis organism. Once sand burial exceed the threshold of the plant, seedlings growth will be restrained and the growth ability even permanently lost. Other factors such as salt spray, insect herbivory, and lack of soil nutrients also affect seed germination and seedling establishment. The precipitation in desert and sand land is unpredictable and irregular. Sand erosion leads roots be exposed to the air and dehydrated to die. However, seedlings of some desert plant have the ability to tolerate desiccation for a period of time after germination. Once there is rain, the seedlings will rivive.
Wang, Yongcui; Alberto, Busso Carlos; Jiang, Deming; Ala, Musa; Li, Xuehua; Zhou, Quanlai; Lin, Jixiang; Ren, Guohua; Jia, Lian
Artemisia wudanica is an endemic, perennial, pioneering psammophyte species in the sand dune ecosystems of western Horqin Sand Land in northern China. However, no studies have addressed how sexual and asexual reproduction modes of A. wudanica perform at the transitional zones between active dune inter-dune lowlands and active dunes. In early spring, quadrats were randomly set up in the study area to monitor surviving seedling and/or ramet density and frequency coming from sexual/asexual reproduction of A. wudanica. Iron sticks were inserted near each quadrat to determine wind erosion intensity (WE). Additionally, soil samples were collected nearby each quadrat to test for soil moisture (SM), organic matter (OM) and pH. Surviving seedlings of A. wudanica showed an inverse response in comparison with ramets to SM, OM and WE. Soil moisture showed the most positive effect, and WE the negative effect, on surviving, sexual reproduction seedlings. Contrarily, WE had the most positive effect, and SM the negative effect, on asexual reproduction ramets. This suggests that increases in SM and decreases in WE should benefit recruitment of A. wudanica seedlings. On the contrary, ramets coming from asexual reproduction showed a different response to environmental factors in transition zone habitats. While SM was not a key constraint for the survival of seedlings, they showed a better, positive response to wind erosion environments. Overall, various study environmental parameters could be improved to foster A. wudanica invasion and settlement in the plant community through different reproductive modes, thereby promoting vegetation restoration and rehabilitation.
Dorothy Sue Dunn de Araujo
Full Text Available A Reserva Biológica Estadual da Praia do Sul está localizada na parte meridional da Ilha Grande - RJ (23º10' S.; 44º17' W.Gr., abrangendo uma área de 3600 ha. Foram identificadas nesta Reserva 5 comunidades vegetais, a saber: psamofila reptante de anteduna, mata de cordão arenoso, mata alagadiça de planície, manguezal e mata de encosta. A fitofisionomia de cada comunidade está descrita, incluindo as espécies mais comuns e a área da Reserva ocupada por cada uma. O levantamento florístico ainda incompleto constitui uma lista de cerca de 300 espécies: as 4 famílias mais importantes são: Leguminose, Rubiaceae, Orchidaceae, BromeliaceaeThe Praia do Sul State Biological Reserve is located on Ilha Grande, State oí Rio de Janeiro, Brazil (23º10' S.; 44º17' W.Gr.. Five plant communities were identified within the limits of this 3600 ha tract: creeping foredune psammophytes, beach ridge forest, coastal plain swamp forest, mangrove and montane forest. The physiognomy of each community is described, including the most common species found and the area of occurrence within the Reserve. A list of approximately 300 species has been compiled to date; the 4 most important families are: Leguminosae, Rubiaceae, Orchidaceae, Bromeliaceae
Full Text Available Annual forage crops have great importance for sustaining animal production in southern Italy. Knowledge of the performance of legume-grass associations under management similar to systems encountered in farm practice is essential for their effective exploitation of the available environmental resources. The purpose of this investigation was to estimate the effects of five cutting managements on the productivity and botanical composition of ten annual fodder crop mixtures in two Mediterranean environments. Ten ternary combinations of one grass (Avena sativa L., oat and Lolium multiflorum Lam., Italian ryegrass, one clover (Trifolium alexandrinum L., berseem; Trifolium incarnatum L., crimson and Trifolium squarrosum L., squarrosum or burr medic (Medicago polymorpha L. and common vetch (Vicia sativa L. were compared in a field trial (split-plot design, 3 replicates in two locations (Cagliari and Foggia, Italy during the 2000-2001 growing season. The cutting treatments included a winter grazing simulation (G, a cutting only regime at early (EF or late flowering (F of legumes and a combination of treatments (GEF and GF. Plant density (no. m-2 prior to cutting, dry matter yield (g m-2 and botanical composition (% were evaluated. Considerable differences were observed in the harvestable dry matter yields of mixtures among cutting treatments in both localities, with treatment F showing the higher values (787.1 and 415.7 g m-2 for Cagliari and Foggia, respectively. The forage species were able to compete and establish good growth during their initial phase in both localities. However, the botanical composition between the two sites differed considerably after the winter period. Particularly, at Foggia, grass dominance was a permanent feature of all treatments, and all the mixtures contained about 84% of grass. Italian ryegrass was the most representative species under all treatments in both sites. Mixtures with Italian ryegrass, crimson or berseem
Full Text Available Introducing nitrogen N2-fixing crops into cereal-based crop rotations reduces N-fertiliser use and may mitigate soil emissions of nitrous oxide (N2O. However, the effect of the cultivation of N2-fixing crops on N2O emissions is still not well understood. N2O from N2-fixing crops can be emitted in two ways: during biological N2 fixation itself and when legume residues are returned to the soil. A field trial was carried out on clover (Trifolium squarrosum Savi to test the role of leguminous crops on N2O emissions in the Mediterranean environment. Monitoring was performed from December 2013 to September 2014. Cumulated N-N2O fluxes were calculated for the growing season (Phase 1 and the post-harvest period (Phase 2 in order to assess the importance of each phase. Our results did not show statistically significant differences between the two phases in term of contribution to the total cumulative N-N2O emissions, in fact Phase 1 and Phase 2 accounted respectively for 43 and 57% of the total.
The importance of morphological characteristics and environmental variables as controlling factors for photo- synthesis and growth of Dicranum polysetum, Pleurozium schreberi and Ptilium crista-castrensis were studied. The three mosses had maximum assimilation capacity in different segments of the shoot and the growth form determined to what degree the capacity could be utilized. CO/sub 2/ fixation was limited by nutrient supply and selectivity affected by the environmental variables. In situ growth in a certain habitat or during a certain season closely corresponded to the oscillation of the variables important for CO/sub 2/ fixation. Application of 2,4-D,MCPA,Triclopyr and Glyphosate to populations of Dicranum, Pleurozium and five co-existing species gave selective effects on assimilation and respiration depending on bryophyte and herbicide. Generally, Glyphosate had negative long-term effects on photosynthesis of coniferous mosses with the exception of Sphagnum squarrosum. MCPA, 2,4-D and Triclopyr immediately decreased CO/sub 2/ fixation to maximally 30% of the control (Pleurozium and Hylocomium splendens). After one month CO/sub 2/ assimilation increased. Effects of varying concentrations of 2,4-D, and Glyphosate were studied and the influence on growth discussed. Assimilation and respiration of Dicranum was negatively related to increasing content of Cu+Zn in the shoot. The effect was significant at concentrations twice the background level.
Full Text Available Estimations of airborne pollen loadings deposited in Tauber traps were studied in a coastal lagoon from south-eastern Pampa grasslands, Argentina, in order to assess their relationship with surface samples and to interpret the representativeness of local, regional and extraregional vegetation. Three different environments were considered: a coastal dune barrier with a psammophytic community, a salt marsh with a halophytic community in Mar Chiquita lagoon, and a freshwater community at Hinojales freshwater lake. Based on a record of surface samples taken from a previous paper, a parametric model was built to classify Tauber samples gathered from the natural vegetation communities of the study area. Results revealed that just like their surface counterparts, Tauber trap records qualitatively reflect the predominant vegetation types, although ecological groups feature different quantitative representations depending on the record type. Pollen loadings showed that airborne pollen transport was predominantly of local range, in accordance with previous results from the same study area. Airborne - surface samples relationships enrich our knowledge of the present environment that could be useful to improve paleoecological interpretations of the area.Se estimó el depósito polínico atmosférico de trampas Tauber en una laguna costera del sudeste de la estepa pampeana argentina, con el objetivo de analizar su relación con muestras de polen superficial e interpretar la representatividad de la vegetación local, regional y extraregional. Se consideraron tres ambientes diferentes: una barrera costera de dunas con vegetación psamofítica, la marisma de la laguna costera Mar Chiquita, con vegetación halofítica, y la laguna continental Hinojales, con vegetación hidrofítica. En base a las muestras de superficie y análisis de un trabajo previo, se construyó un modelo paramétrico para clasificar las muestras Tauber tomadas en la vegetación natural del
W. M. M. Eddie
Full Text Available Pollen grains of Rhigiophyllum squarrosum Hochst., Siphocodon spartioides Turcz. and S. debilis Schltr., are flattened and triangular with pores at the angles. This morphology is radically different from known pollen of the Campanulaceae s.sfr:: the Campanulaceae are treated here as a family separate from the Lobeliaceae, Cyphiaceae, Nemacladaceae, Pentaphragmataceae and Sphenocleaceae (Lammers 1992. As traditionally conceived, the Campanulaceae is very heterogeneous and, in many classifications, these families were treated as subfamilies of a much-enlarged Campanulaceae. The consistently different floral morphology, biochemistry and pollen structure of the Lobeliaceae favours the recognition of this predominantly tropical group as a separate family. The pollen grains of these species are described in comparison with other members of the Campanulaceae. Based on surface characteristics of their pollen grains, we conclude that they represent an early offshoot o f the wahlenbergioid lineage in southern Africa. We suggest that this unique pollen may also be the result of a highly selective regime in the fynbos, associated with specialized pollinators, and base-poor soils, in addition to possible adaptations for ant dispersal and fire. Rhigiophyllum Hochst. and Siphocodon Turcz. are also unique in having free carpel-like structures within the ovary. These shrink to form seed pockets around the seeds and disperse as units when the capsule matures. Data from molecular studies support the contention that these taxa form a sister group to all other wahlenbergioids and that this should be formally recognized in a classification system. We treat Rhigiophyllum and Siphocodon within the Campanulaceae: Wahlenbergioideae, as a separate tribe, the Rhigiophylleae tribus nov., the species of which are distinguishable from other wahlenbergioids by unique angulaperturatc pollen, epipetalous stamens, free carpel-like structures and seed pockets.
W. M. M. Eddie
Full Text Available Pollen grains of Rhigiophyllum squarrosum Hochst., Siphocodon spartioides Turcz. and S. debilis Schltr., are flattened and triangular with pores at the angles. This morphology is radically different from known pollen of the Campanulaceae s.sfr:: the Campanulaceae are treated here as a family separate from the Lobeliaceae, Cyphiaceae, Nemacladaceae, Pentaphragmataceae and Sphenocleaceae (Lammers 1992. As traditionally conceived, the Campanulaceae is very heterogeneous and, in many classifications, these families were treated as subfamilies of a much-enlarged Campanulaceae. The consistently different floral morphology, biochemistry and pollen structure of the Lobeliaceae favours the recognition of this predominantly tropical group as a separate family.The pollen grains of these species are described in comparison with other members of the Campanulaceae. Based on surface characteristics of their pollen grains, we conclude that they represent an early offshoot o f the wahlenbergioid lineage in southern Africa. We suggest that this unique pollen may also be the result of a highly selective regime in the fynbos, associated with specialized pollinators, and base-poor soils, in addition to possible adaptations for ant dispersal and fire. Rhigiophyllum Hochst. and Siphocodon Turcz. are also unique in having free carpel-like structures within the ovary. These shrink to form seed pockets around the seeds and disperse as units when the capsule matures. Data from molecular studies support the contention that these taxa form a sister group to all other wahlenbergioids and that this should be formally recognized in a classification system. We treat Rhigiophyllum and Siphocodon within the Campanulaceae: Wahlenbergioideae, as a separate tribe, the Rhigiophylleae tribus nov., the species of which are distinguishable from other wahlenbergioids by unique angulaperturatc pollen, epipetalous stamens, free carpel-like structures and seed pockets.
Vicherová, Eliška; Hájek, Michal; Šmilauer, Petr; Hájek, Tomáš
Sphagnum expansion to alkaline fens has accelerated during the last decades in Europe, leading to changes in diversity, habitat distributions and carbon storage. The causes are still not clearly understood and involve an interplay between climate change, hydrology, nutrient supply and Sphagnum physiology. We conducted a 4-year field experiment in eight fens in Central European highlands and assessed survival and establishment of individual apical shoot fragments of S. flexuosum, S. warnstorfii and S. squarrosum transplanted along the microtopographical gradient. In a laboratory experiment, we tested combined effects of desiccation and high calcium bicarbonate concentration on Sphagnum survival. We found that in unflooded positions, living shoots of Sphagnum and brown mosses lowered [Ca2+] and pH in their capillary water, in contrast to dead fragments; yet without differences between species. Survival and expansion of Sphagnum fragments, which did not die of acute calcium toxicity during first weeks/months, was negatively affected by dry weather and alkaline water chemistry, reflecting Sphagnum intolerance to desiccation and to combined high [Ca2+] and pH. Shoot fragments expanded to patches only when precipitation was high. Interestingly, non-toxic concentration of calcium bicarbonate reduced desiccation damage in Sphagnum, probably through protection of membranes or other cell components. This mechanism would facilitate Sphagnum survival in elevated, frequently desiccated microhabitats of calcareous fens such as brown-moss hummocks. However, since water-retaining capacity of few Sphagnum shoots is insufficient to change water chemistry in its surroundings, surface acidification may occur only once the environment (e.g. sufficient humidity) enabled expansion to larger mats. Then, the retained rainwater together with hardly decomposable Sphagnum litter would separate mire surface from groundwater, speeding up successional shift towards poor fens. Sphagnum expansion
van den Elzen, Eva; Kox, Martine A. R.; Harpenslager, Sarah F.; Hensgens, Geert; Fritz, Christian; Jetten, Mike S. M.; Ettwig, Katharina F.; Lamers, Leon P. M.
In pristine Sphagnum-dominated peatlands, (di)nitrogen (N2) fixing (diazotrophic) microbial communities associated with Sphagnum mosses contribute substantially to the total nitrogen input, increasing carbon sequestration. The rates of symbiotic nitrogen fixation reported for Sphagnum peatlands, are, however, highly variable, and experimental work on regulating factors that can mechanistically explain this variation is largely lacking. For two common fen species (Sphagnum palustre and S. squarrosum) from a high nitrogen deposition area (25 kg N ha-1 yr-1), we found that diazotrophic activity (as measured by 15 - 15N2 labeling) was still present at a rate of 40 nmol N gDW-1 h-1. This was surprising, given that nitrogen fixation is a costly process. We tested the effects of phosphorus availability and buffering capacity by bicarbonate-rich water, mimicking a field situation in fens with stronger groundwater or surface water influence, as potential regulators of nitrogen fixation rates and Sphagnum performance. We expected that the addition of phosphorus, being a limiting nutrient, would stimulate both diazotrophic activity and Sphagnum growth. We indeed found that nitrogen fixation rates were doubled. Plant performance, in contrast, did not increase. Raised bicarbonate levels also enhanced nitrogen fixation, but had a strong negative impact on Sphagnum performance. These results explain the higher nitrogen fixation rates reported for minerotrophic and more nutrient-rich peatlands. In addition, nitrogen fixation was found to strongly depend on light, with rates 10 times higher in light conditions suggesting high reliance on phototrophic organisms for carbon. The contrasting effects of phosphorus and bicarbonate on Sphagnum spp. and their diazotrophic communities reveal strong differences in the optimal niche for both partners with respect to conditions and resources. This suggests a trade-off for the symbiosis of nitrogen fixing microorganisms with their Sphagnum
Landi, Silvia; D'Errico, Giada; Gagnarli, Elena; Simoni, Sauro; Goggioli, Donatella; Guidi, Silvia; D'Avino, Lorenzo; Lagomarsino, Alessandra; Valboa, Giuseppe; Castaldini, Maurizio; Elio Agnelli, Alessandro; Fantappiè, Maria; Lorenzetti, Romina; Priori, Simone; Costantini, Edoardo A. C.
In Italian vineyards, it is quite common to have areas characterized by problems in vine health, grape production and quality, often caused by improper land preparation before vine plantation and/or management. Causes for soil malfunctioning can include reduced contribution of the soil fauna to the ecosystem services such as nutrient cycles and organic matter turnover. ReSolVe is a transnational and interdisciplinary project, supported by Core-Organic+ program, aimed at testing the effects of selective agronomic strategies for restoring optimal soil functionality in degraded areas within organic vineyard. For this purpose, the evaluation and biomonitoring of the abundance of soil mesofauna, nematodes and microarthropods, represents an efficient tool to characterize the effects of crop management on soil quality. Assessing enzyme activities involved in the main biogeochemical cycling of C, N, P and S can also provide indication of soil functions and health status. Italian experimental plots are situated in two commercial farms in Tuscany: i) Fontodi, Panzano in Chianti (FI), which has been managed organically for more than 20 years and ii) San Disdagio, Roccastrada (GR), under organic farming since 2014. In each farm, three plots (250 m2 each) in the degraded areas and three relative control plots in the non-degraded areas were selected. The different restoring strategies implemented in each area were: i) compost, produced on farm by manure + pruning residue + grass, ii) faba bean and winter barley green manure, iii) dry mulching after sowing with Trifolium squarrosum L. Each treated and control plot has been studied for soil nematodes, microarthropods, enzymatic activity, and organic matter turnover using tea-bag index, as well as total organic carbon (TOC) and total nitrogen (TN). Soil sampling was carried out to 0-30 cm depth for TOC, TN, enzymes and nematodes and to 10 cm for microarthropods. Tea-bag index was determined following the Keuskamp et al. method
Priori, Simone; Agnelli, Alessandro; Castaldini, Maurizio; D'Avino, Lorenzo; D'Errico, Giada; Gagnarli, Elena; Giudi, Silvia; Goggioli, Donatella; Lagomarsino, Alessandra; Landi, Silvia; Leprini, Marco; Pellegrini, Sergio; Perria, Rita; Puccioni, Sergio; Simoni, Sauro; Storchi, Paolo; Valboa, Giuseppe; Zombardo, Alessandra; Costantini, Edoardo
In both conventional and organic Italian vineyards, it is quite common to have areas characterized by problems in vine health, grape production and quality, often caused by improper land preparation before vine plantation and/or management. Causes for soil malfunctioning can include: reduced contribution of the soil fauna to the ecosystem services (i.e. nutrient cycles), poor organic matter content, imbalance of some element ratio, altered pH, water deficiency, soil compaction and/or scarce oxygenation. ReSolVe is a transnational and interdisciplinary 3-years research project aimed at testing the effects of selected organic strategies for restoring optimal soil functionality in degraded areas within vineyard. The different restoring strategies implemented in each plot will be: i) compost produced on farm by manure + pruning residue + grass, ii) faba bean and barley green manure, iii) sowing and dry mulching with Trifolium squarrosum L. During two years of such treatments, the trend of the soil features and the grapevine status will be monitored in detail, to reveal the positive and negative effects of such treatments. The project involves 8 research groups in 6 different EU countries (Italy, France, Spain, Sweden, Slovenia, and Turkey), with experts from several disciplines, including soil science, ecology, microbiology, grapevine physiology, viticulture, and biometry. The experimental vineyards are situated in Italy (Chianti hills and Maremma plain, Tuscany), France (Bordeaux and Languedoc), Spain (La Rioja) and Slovenia (Primorska) for winegrape, and in Turkey (Adana and Mersin) for table grape. Soil features before implementing restoring strategies showed lower content of soil organic matter and enzyme activities, and higher carbonates in degraded areas than in the non-degraded areas. The Biological Soil Quality values of microarthropods were always high, in comparison with data registered in similarly managed vineyards or stable ecosystems, and the data showed