[Objective] The aim was to study pollen morphology of Pennisetum native species.[Method] We carried out the observation by optical microscope and scanning electron microscope on six materials of pollen grains includin...[Objective] The aim was to study pollen morphology of Pennisetum native species.[Method] We carried out the observation by optical microscope and scanning electron microscope on six materials of pollen grains including three species and three transmogrifications from one variant of Pennisetum native species.[Result] The pollen grains were globose or subglobose.Germination aperture which located at distal side was singular and its circumambience was thickened.Pollen wall which had two layers was thin and easy to be crimpled.There were obvious differences between ektexine ornamentations as well as particle sizes.[Conclusion] The question of low seed-setting rate of Pennisetum native species had relations with the withered pollen morphology to some extent.The differences between pollen morphology as well as ektexine ornamentations accorded with the division of species and variants from Pennisetum.In addition,the relationship between pollen morphology and seed-setting rate provided references to introduce good grass seed and choose breeding parent materials of Pennisetum.展开更多
There were two peaks of seasonal changes of the calorific value in shoot and leaves of Calamagrostis epigejos in middle June and in the early August respectively. The calorific value in stem presented a single peak cu...There were two peaks of seasonal changes of the calorific value in shoot and leaves of Calamagrostis epigejos in middle June and in the early August respectively. The calorific value in stem presented a single peak curve which appeared in the early August. The calorific values in inflorescence and dead standing showed a fluctuation and the peak value of inflorescence was in the early September and that of dead standing was in middle June. The seasonal changes of energy standing crop on the above-ground part synchronized with that of the biomass, which presented a single peak curve. The energy allocated to each organ in different seasons was in the order as leaves > stem > inflorescence in middle June, leaves > stem > dead standing > inflorescence in early July, leaves > stem > inflorescence > dead standing in middle July, and leaves > stem > dead standing > inflorescence from August to September. The vertical allocation of energy in the parts of above-ground was that the energy value gradually increased from the surface to the 20 cm high level and the maximum value at the 10 - 20 cin high level which made up 26.91% of energy on the above-ground partion, and then it was decreased. In the under-ground portion, the energy value progressively decreased with depth and the maximum value was at 0 - 10 cm depth layer which made up 69.01% of energy of the under-ground portion.展开更多
Planting mulch grasses in orchards,as a technique to build ecological orchards,can be one of the strategic approaches for rural revitalization.This study sorted out the common varieties of mulch grasses and analyzed t...Planting mulch grasses in orchards,as a technique to build ecological orchards,can be one of the strategic approaches for rural revitalization.This study sorted out the common varieties of mulch grasses and analyzed their application statuses in orchards of southern China.According to different utilization purposes of mulch grasses in orchards,scientific suggestions were given from aspects of grass selection,cultivation techniques,management methods and use modes.The study will provide reference for the construction of ecological orchards in southern China.展开更多
Phytoremediation is a relatively new approach in remediating ecosystems contaminated by ecotoxic pollutants such as herbicides or heavy metals and especially cadmium （Cd）. Certain indicators of phytoremediation, as ...Phytoremediation is a relatively new approach in remediating ecosystems contaminated by ecotoxic pollutants such as herbicides or heavy metals and especially cadmium （Cd）. Certain indicators of phytoremediation, as plant growth, tolerance to Cd, and uptake, transfer factor （TF） and percent removal of Cd, were studied for 11 crops and 8 weed species in soil with varying levels of Cd （0-240 mg Cd kg＂ soil） under controlled environment. Cadmium accumulated mainly in roots （51%-86%, depending on the species）, while a 14%-49% was transferred to shoots （except for four species） the concentration being positively related to Cd level in soil. Highest concentration in the above ground plant part was measured in sugarbeets （41-101 mg Cd kg-1 DW） followed by Bromus sterilis （75）, Eruca sativa （32-82）, Cichorium intibus （35-80）, and maize （60 mg Cd kgl）. Based on the results it is concluded that sugarbeets, maize, C. intibus, B. sterilis, E. sativa, Apium graveolens, and Vicia sativa seem to have a potential in remediating Cd contaminated soils.展开更多
The region of Tlemcen is situated in the north-west of Algeria. The aridity of the climate had lead to the development of the matorral, a state of degradation of the Mediterranean, and the composed xerophytes plants s...The region of Tlemcen is situated in the north-west of Algeria. The aridity of the climate had lead to the development of the matorral, a state of degradation of the Mediterranean, and the composed xerophytes plants such as doum and diss, had been found. Chamaerops humilis, xerophyte plant, with special morphologic and botanic character presents a resistance of these climatic. The authors have proposed study of fauna closly linked to this plant. A faunistic inventory was realized in the Mansourah area （region of Tlemcen）. Four stations have been described. Collecting sample was performed during June 2003-Mar. 2004, replying on sixteen （16） prelevements. The number of species were estimated of about 136, in which 111 are Arthropoda, the Entomofauna represented by 97 species and the other inventory are Arachnida by 8 species and Myriapoda by 6 species. 18 species are related to Gastropoda. The vertebrates are few. The importance of different groups＇ recolted on the Chamaerops humilis in the four stations is done particular to the insects. Analysis factorial correspondence （A.F.C） show different grouping of animal species.展开更多
Fifty two accessions of Festuca pratensis Huds. were analysed of which 18 had been collected in Switzerland and 32 in Bulgaria. SDS-PAGE of seed proteins was implemented to detect genetic variation among ecotype popul...Fifty two accessions of Festuca pratensis Huds. were analysed of which 18 had been collected in Switzerland and 32 in Bulgaria. SDS-PAGE of seed proteins was implemented to detect genetic variation among ecotype populations using a modification of UPOV method for barley. The modification concerns mainly protein extracting procedure as detailed described in the protocol. The two cultivars Preval and Cosmolit were used as standards. Cluster analyses and correspondence analyses/scatter plot were used as statistic approaches for determining genetic diversity among individual ecotypes and groups of ecotypes. Electrophoretic spectra of proteins show clear differences among local accessions in relation to their origin. In Swiss ecotypes 32 protein fragments were determined whereas in Bulgarian local populations their number was 68. Each of the two eco-groups possesses fragments that appear in all accessions of the group. The number of monomorphic bands within Bulgarian local ecotypes is four whereas their number in Swiss ecotypes is 12. Four monomorphic bands appearing in all proteinograms no difference of eco-groups was identified with Rm values of： 0.43, 0.55, 0.58, 0.82. A higher level of protein band polymorphism was proven in Bulgarian ecotypes in comparison with Swiss ecotypes. Thirty seven polymorphic bands occurred exclusively in the Bulgarian local ecotypes and had a frequency of 0.03 or higher whereas within Swiss ecotypes was detected one unique protein fragment. SDS-PAGE ＂fingerprinting＂ is suggested as a fast and easy approach to differentiate F. pratensis ecotypes by their origin as well for detection of foreign germplasm for inclusion in breeding programs.展开更多
Species＇ partitioning of resources remains one of the most integral components for understanding community assem- bly. Analysis of stable carbon and nitrogen isotopes in animal tissues has the potential to help resol...Species＇ partitioning of resources remains one of the most integral components for understanding community assem- bly. Analysis of stable carbon and nitrogen isotopes in animal tissues has the potential to help resolve patterns of partitioning be- cause these proxies represent the individual＇s diet and trophic niche, respectively. Using free-ranging rodents in a southern Afri- can savanna as a model community, we find that syntopic species within habitats occupy distinct isotope niches. Moreover, spe- cies with strongly overlapping isotope niches did not overlap in their spatial distribution patterns, suggesting an underlying effect of competitive exclusion. Niche conservatism appears to characterize the behaviour of most species in our sample - with little or no observed changes across habitats - with the exception of one species, Mastomys coucha. This species displayed a generalist distribution, being found in similar abundances across a variety of habitats. This spatial pattern was coupled with a generalist isotope niche that shifted across habitats, likely in response to changes in species composition over the same spatial gradient. The case for M. coucha supports contentions that past competition effects played a significant evolutionary role in shaping community structures of today, including the absence of strong interspecific niche overlaps within particular habitats. Our study highlights the value of stable isotope approaches to help resolve key questions in community ecology, and moreover introduces novel ana- lytical approaches to quantifying isotope niche breadths and niche overlaps that are easily comparable with traditional metrices展开更多
基金Supported by Special Fund for Basic Research Operating Expenses of Nonprofit Research Institutions at the Central Level(BRF090202)~~
文摘[Objective] The aim was to study pollen morphology of Pennisetum native species.[Method] We carried out the observation by optical microscope and scanning electron microscope on six materials of pollen grains including three species and three transmogrifications from one variant of Pennisetum native species.[Result] The pollen grains were globose or subglobose.Germination aperture which located at distal side was singular and its circumambience was thickened.Pollen wall which had two layers was thin and easy to be crimpled.There were obvious differences between ektexine ornamentations as well as particle sizes.[Conclusion] The question of low seed-setting rate of Pennisetum native species had relations with the withered pollen morphology to some extent.The differences between pollen morphology as well as ektexine ornamentations accorded with the division of species and variants from Pennisetum.In addition,the relationship between pollen morphology and seed-setting rate provided references to introduce good grass seed and choose breeding parent materials of Pennisetum.
文摘There were two peaks of seasonal changes of the calorific value in shoot and leaves of Calamagrostis epigejos in middle June and in the early August respectively. The calorific value in stem presented a single peak curve which appeared in the early August. The calorific values in inflorescence and dead standing showed a fluctuation and the peak value of inflorescence was in the early September and that of dead standing was in middle June. The seasonal changes of energy standing crop on the above-ground part synchronized with that of the biomass, which presented a single peak curve. The energy allocated to each organ in different seasons was in the order as leaves > stem > inflorescence in middle June, leaves > stem > dead standing > inflorescence in early July, leaves > stem > inflorescence > dead standing in middle July, and leaves > stem > dead standing > inflorescence from August to September. The vertical allocation of energy in the parts of above-ground was that the energy value gradually increased from the surface to the 20 cm high level and the maximum value at the 10 - 20 cin high level which made up 26.91% of energy on the above-ground partion, and then it was decreased. In the under-ground portion, the energy value progressively decreased with depth and the maximum value was at 0 - 10 cm depth layer which made up 69.01% of energy of the under-ground portion.
基金Supported by National Key Research&Development Project(2018YFD0800501)Hunan Key Research&Development Project(2016JC2028)Science and Technology Innovation Project in Hunan Academy of Agricultural Sciences(2018QN33)~~
文摘Planting mulch grasses in orchards,as a technique to build ecological orchards,can be one of the strategic approaches for rural revitalization.This study sorted out the common varieties of mulch grasses and analyzed their application statuses in orchards of southern China.According to different utilization purposes of mulch grasses in orchards,scientific suggestions were given from aspects of grass selection,cultivation techniques,management methods and use modes.The study will provide reference for the construction of ecological orchards in southern China.
文摘Phytoremediation is a relatively new approach in remediating ecosystems contaminated by ecotoxic pollutants such as herbicides or heavy metals and especially cadmium （Cd）. Certain indicators of phytoremediation, as plant growth, tolerance to Cd, and uptake, transfer factor （TF） and percent removal of Cd, were studied for 11 crops and 8 weed species in soil with varying levels of Cd （0-240 mg Cd kg＂ soil） under controlled environment. Cadmium accumulated mainly in roots （51%-86%, depending on the species）, while a 14%-49% was transferred to shoots （except for four species） the concentration being positively related to Cd level in soil. Highest concentration in the above ground plant part was measured in sugarbeets （41-101 mg Cd kg-1 DW） followed by Bromus sterilis （75）, Eruca sativa （32-82）, Cichorium intibus （35-80）, and maize （60 mg Cd kgl）. Based on the results it is concluded that sugarbeets, maize, C. intibus, B. sterilis, E. sativa, Apium graveolens, and Vicia sativa seem to have a potential in remediating Cd contaminated soils.
文摘The region of Tlemcen is situated in the north-west of Algeria. The aridity of the climate had lead to the development of the matorral, a state of degradation of the Mediterranean, and the composed xerophytes plants such as doum and diss, had been found. Chamaerops humilis, xerophyte plant, with special morphologic and botanic character presents a resistance of these climatic. The authors have proposed study of fauna closly linked to this plant. A faunistic inventory was realized in the Mansourah area （region of Tlemcen）. Four stations have been described. Collecting sample was performed during June 2003-Mar. 2004, replying on sixteen （16） prelevements. The number of species were estimated of about 136, in which 111 are Arthropoda, the Entomofauna represented by 97 species and the other inventory are Arachnida by 8 species and Myriapoda by 6 species. 18 species are related to Gastropoda. The vertebrates are few. The importance of different groups＇ recolted on the Chamaerops humilis in the four stations is done particular to the insects. Analysis factorial correspondence （A.F.C） show different grouping of animal species.
文摘Fifty two accessions of Festuca pratensis Huds. were analysed of which 18 had been collected in Switzerland and 32 in Bulgaria. SDS-PAGE of seed proteins was implemented to detect genetic variation among ecotype populations using a modification of UPOV method for barley. The modification concerns mainly protein extracting procedure as detailed described in the protocol. The two cultivars Preval and Cosmolit were used as standards. Cluster analyses and correspondence analyses/scatter plot were used as statistic approaches for determining genetic diversity among individual ecotypes and groups of ecotypes. Electrophoretic spectra of proteins show clear differences among local accessions in relation to their origin. In Swiss ecotypes 32 protein fragments were determined whereas in Bulgarian local populations their number was 68. Each of the two eco-groups possesses fragments that appear in all accessions of the group. The number of monomorphic bands within Bulgarian local ecotypes is four whereas their number in Swiss ecotypes is 12. Four monomorphic bands appearing in all proteinograms no difference of eco-groups was identified with Rm values of： 0.43, 0.55, 0.58, 0.82. A higher level of protein band polymorphism was proven in Bulgarian ecotypes in comparison with Swiss ecotypes. Thirty seven polymorphic bands occurred exclusively in the Bulgarian local ecotypes and had a frequency of 0.03 or higher whereas within Swiss ecotypes was detected one unique protein fragment. SDS-PAGE ＂fingerprinting＂ is suggested as a fast and easy approach to differentiate F. pratensis ecotypes by their origin as well for detection of foreign germplasm for inclusion in breeding programs.
基金Acknowledgements This research was funded by the Na- tional Science Foundation （NSF, USA） and the Palaeontolo- gical Scientific Trust （PAST, RSA）. We thank Jurie du Plessis, Isak Sekhuni, Carl Pohl, Bianca Bester, Ethan Codron, and Jesse Codron for assistance in the field. Two anonymous re- viewers and the journal editor are thanked for useful com- ments that helped improve the quality of this paper. The re- search and protocols were approved by the Gauteng Provincial Government, authorization number MA： 8/1/1/6/1-2011/01/001.
文摘Species＇ partitioning of resources remains one of the most integral components for understanding community assem- bly. Analysis of stable carbon and nitrogen isotopes in animal tissues has the potential to help resolve patterns of partitioning be- cause these proxies represent the individual＇s diet and trophic niche, respectively. Using free-ranging rodents in a southern Afri- can savanna as a model community, we find that syntopic species within habitats occupy distinct isotope niches. Moreover, spe- cies with strongly overlapping isotope niches did not overlap in their spatial distribution patterns, suggesting an underlying effect of competitive exclusion. Niche conservatism appears to characterize the behaviour of most species in our sample - with little or no observed changes across habitats - with the exception of one species, Mastomys coucha. This species displayed a generalist distribution, being found in similar abundances across a variety of habitats. This spatial pattern was coupled with a generalist isotope niche that shifted across habitats, likely in response to changes in species composition over the same spatial gradient. The case for M. coucha supports contentions that past competition effects played a significant evolutionary role in shaping community structures of today, including the absence of strong interspecific niche overlaps within particular habitats. Our study highlights the value of stable isotope approaches to help resolve key questions in community ecology, and moreover introduces novel ana- lytical approaches to quantifying isotope niche breadths and niche overlaps that are easily comparable with traditional metrices
