Information on the genetic diversity of wild rice species in Sri Lanka is relatively meagre,though it plays a key role in crop improvement programs of cultivated rice(Oryza sativa L.).The present study was carried out...Information on the genetic diversity of wild rice species in Sri Lanka is relatively meagre,though it plays a key role in crop improvement programs of cultivated rice(Oryza sativa L.).The present study was carried out to identify the morphological variation pattern of the wild populations of O.nivara in Sri Lanka.Seven populations(P1 to P7)collected from different agro-ecological regions were characterized in a common garden based on nine morphological traits.The findings revealed a high level of phenotypic variation between populations when compared to within a population.The most variable traits were the flag leaf panicle neck length(FLPNL)and flag leaf angle(FLA),whereas the least variable trait was the flag leaf length(FLL).Box plots clearly illustrated the large differentiation of phenotypic traits in the entire distribution of wild rice populations.The cumulative values of the two principal components,i.e.,FLPNL and FLA,explained 58.7%of the total variance.Populations from similar natural habitats clustered together.The P7 was adapted to intercept more sunlight by increasing flag leaf width(FLW)and FLA to compete with weeds and other shrubs.P2 and P5 were the most closely related populations representing approximately similar ecological conditions of the dry zone.The P3 population from the intermediate zone showed a vigorous plant growth with the highest plant height,culm girth and awn length(P<0.05).Knowledge of such morphological diversity would facilitate designing conservation strategies and basic information for the proper utilization of wild resources in rice genetic improvement.展开更多
The present investigation deals with the isolation of endophytic fungi from leaf,stem,root and pitcher cup tissue segments of the endemic carnivorous plant Nepenthes khaisana collected from its natural habitat for a p...The present investigation deals with the isolation of endophytic fungi from leaf,stem,root and pitcher cup tissue segments of the endemic carnivorous plant Nepenthes khaisana collected from its natural habitat for a period of one year at monthly intervals.Out of 576 tissue segments inoculated,a total of 39 fungal endophytes along with mycelia sterilia were isolated from the host plant.To assess the diversity of fungal endophytes,the colonization frequency(%CF)was first recorded using past software and MS excel.The fungal isolates were mainly composed of the phylum Ascomycota,followed by Zygomycota and Oomycota.The highest percentage colonization frequency on an average of three replicates were recorded in pitcher cup tissues followed by root,stem and least was recorded in leaf of the host plant.Among the isolates,Globisporangium irregulare(83.33%)showed high%CF in leaf,Juxtiphoma eupyrena(83.33%)reported to have maximum%CF in the stem,Talaromyces ruber(66.66%)was recorded high%CF in root and mycelia sterilia(white)were showed the highest%CF in the segments of leaf.The diversity index analyses of Shannon-Weiner,Simpson’s index,species richness and species evenness of diversity showed that leaf of N.Khasiana has the highest diversity than the other parts of the plant.So,with the help of the present finding,we conclude that the distribution of fungal endophytes and their%colonization frequencies vary within different tissues of the host plant and thus,this confirms tissue specificity nature of endophytic fungi.展开更多
Jellyfish blooms occur worldwide and have resulted in serious problems in tourism,fisheries,coastal industries,and the marine ecosystem.The life cycle of scyphozoan jellyfish consists of a pelagic medusa stage and a b...Jellyfish blooms occur worldwide and have resulted in serious problems in tourism,fisheries,coastal industries,and the marine ecosystem.The life cycle of scyphozoan jellyfish consists of a pelagic medusa stage and a benthic polyp stage.Success of asexual reproduction of the polyps determines directly the number of medusae;thus,the polyp stage is the key to understanding the population dynamics of medusae.Nemopilema nomurai,Aurelia coerulea,and Rhopilema esculentum are three scyphozoan jellyfish commonly inhabit in Chinese coastal waters.Polyps of A.coerulea are easily visible,while those of N.nomurai and R.esculentum remain yet to be found in the wild.However,distribution of the medusa indicates that the polyps of all three species may occur together.To evaluate the distribution pattern of polyps of the three species and explore intraguild predation by the polyps,we conducted a laboratory experiment that considered the attachment sequence and size relationship of calyx diameter of the polyps.We found that the polyps of A.coerulea preyed on polyps of the other two species in all treatments,except when polyps of R.esculentum were bigger than those of A.coerulea.The polyps of R.esculentum preyed on the polyps of N.nomurai only when polyps of R.esculentum attached first and were bigger than those of N.nomurai.Colonies of N.nomurai polyps were rarely found in the places inhabited by A.coerulea polyps.In addition,A.coerulea polyps are known to inhabit at depths of less than 20 m in coastal sea,thus,we speculate that N.nomurai polyp colonies might occur at depths of more than 20 m.Therefore,our finding that polyps of A.coerulea aggressively preyed on polyps of other species may help understand other such systems of jellyfish bloom in the world.展开更多
Edible birds’nests(EBNs)have traditionally been produced in Southeast Asia.Indonesian farmers construct buildings for swiftlets and harvest their nests.EBN farming does not directly degrade forest resources and is th...Edible birds’nests(EBNs)have traditionally been produced in Southeast Asia.Indonesian farmers construct buildings for swiftlets and harvest their nests.EBN farming does not directly degrade forest resources and is therefore considered a sustainable means of production,whereas the expansion of other agricultural activities often relies on the degradation of natural resources.This study examines the relationship between natural resources and agricultural livelihoods,focusing on Indonesian EBN farmers.Using survey data that we collected in 2017,combined with satellite information on the extent of the forest in Central Kalimantan,Indonesia,we measured production efficiency and identified the natural and social factors that enhance production performance.The results show that a forest extent ranging between 2,000 and 6,000 meters from nesting building is positively associated with the production efficiency of EBN farming,perhaps because extensive forest could help swiftlets to collect food and build nests.Conversely,while EBN farming is a sustainable and profitable option,the initial costs of constructing buildings to house swiftlets may deter farmers from participating in the process.展开更多
基金the National Research Council(Grant No.NRC 15-108)the National Science Foundation of Sri Lanka.Taif University Researchers Supporting Project Number(TURSP-2020/59),Taif University,Taif,Saudi Arabia.
文摘Information on the genetic diversity of wild rice species in Sri Lanka is relatively meagre,though it plays a key role in crop improvement programs of cultivated rice(Oryza sativa L.).The present study was carried out to identify the morphological variation pattern of the wild populations of O.nivara in Sri Lanka.Seven populations(P1 to P7)collected from different agro-ecological regions were characterized in a common garden based on nine morphological traits.The findings revealed a high level of phenotypic variation between populations when compared to within a population.The most variable traits were the flag leaf panicle neck length(FLPNL)and flag leaf angle(FLA),whereas the least variable trait was the flag leaf length(FLL).Box plots clearly illustrated the large differentiation of phenotypic traits in the entire distribution of wild rice populations.The cumulative values of the two principal components,i.e.,FLPNL and FLA,explained 58.7%of the total variance.Populations from similar natural habitats clustered together.The P7 was adapted to intercept more sunlight by increasing flag leaf width(FLW)and FLA to compete with weeds and other shrubs.P2 and P5 were the most closely related populations representing approximately similar ecological conditions of the dry zone.The P3 population from the intermediate zone showed a vigorous plant growth with the highest plant height,culm girth and awn length(P<0.05).Knowledge of such morphological diversity would facilitate designing conservation strategies and basic information for the proper utilization of wild resources in rice genetic improvement.
文摘The present investigation deals with the isolation of endophytic fungi from leaf,stem,root and pitcher cup tissue segments of the endemic carnivorous plant Nepenthes khaisana collected from its natural habitat for a period of one year at monthly intervals.Out of 576 tissue segments inoculated,a total of 39 fungal endophytes along with mycelia sterilia were isolated from the host plant.To assess the diversity of fungal endophytes,the colonization frequency(%CF)was first recorded using past software and MS excel.The fungal isolates were mainly composed of the phylum Ascomycota,followed by Zygomycota and Oomycota.The highest percentage colonization frequency on an average of three replicates were recorded in pitcher cup tissues followed by root,stem and least was recorded in leaf of the host plant.Among the isolates,Globisporangium irregulare(83.33%)showed high%CF in leaf,Juxtiphoma eupyrena(83.33%)reported to have maximum%CF in the stem,Talaromyces ruber(66.66%)was recorded high%CF in root and mycelia sterilia(white)were showed the highest%CF in the segments of leaf.The diversity index analyses of Shannon-Weiner,Simpson’s index,species richness and species evenness of diversity showed that leaf of N.Khasiana has the highest diversity than the other parts of the plant.So,with the help of the present finding,we conclude that the distribution of fungal endophytes and their%colonization frequencies vary within different tissues of the host plant and thus,this confirms tissue specificity nature of endophytic fungi.
基金Supported by the National Key Research and Development Program of China(No.2017YFC1404405)the Taishan Scholar Climbing Plan to Sun Song,the Shandong Joint Fund for Marine Ecology and Environmental Sciences(No.U1606404)the Aoshan Science and Technology Innovation Project(No.2016ASKJ02-2)。
文摘Jellyfish blooms occur worldwide and have resulted in serious problems in tourism,fisheries,coastal industries,and the marine ecosystem.The life cycle of scyphozoan jellyfish consists of a pelagic medusa stage and a benthic polyp stage.Success of asexual reproduction of the polyps determines directly the number of medusae;thus,the polyp stage is the key to understanding the population dynamics of medusae.Nemopilema nomurai,Aurelia coerulea,and Rhopilema esculentum are three scyphozoan jellyfish commonly inhabit in Chinese coastal waters.Polyps of A.coerulea are easily visible,while those of N.nomurai and R.esculentum remain yet to be found in the wild.However,distribution of the medusa indicates that the polyps of all three species may occur together.To evaluate the distribution pattern of polyps of the three species and explore intraguild predation by the polyps,we conducted a laboratory experiment that considered the attachment sequence and size relationship of calyx diameter of the polyps.We found that the polyps of A.coerulea preyed on polyps of the other two species in all treatments,except when polyps of R.esculentum were bigger than those of A.coerulea.The polyps of R.esculentum preyed on the polyps of N.nomurai only when polyps of R.esculentum attached first and were bigger than those of N.nomurai.Colonies of N.nomurai polyps were rarely found in the places inhabited by A.coerulea polyps.In addition,A.coerulea polyps are known to inhabit at depths of less than 20 m in coastal sea,thus,we speculate that N.nomurai polyp colonies might occur at depths of more than 20 m.Therefore,our finding that polyps of A.coerulea aggressively preyed on polyps of other species may help understand other such systems of jellyfish bloom in the world.
基金This work was supported by JSPS KAKENHI[Grant Number JP19H04340].
文摘Edible birds’nests(EBNs)have traditionally been produced in Southeast Asia.Indonesian farmers construct buildings for swiftlets and harvest their nests.EBN farming does not directly degrade forest resources and is therefore considered a sustainable means of production,whereas the expansion of other agricultural activities often relies on the degradation of natural resources.This study examines the relationship between natural resources and agricultural livelihoods,focusing on Indonesian EBN farmers.Using survey data that we collected in 2017,combined with satellite information on the extent of the forest in Central Kalimantan,Indonesia,we measured production efficiency and identified the natural and social factors that enhance production performance.The results show that a forest extent ranging between 2,000 and 6,000 meters from nesting building is positively associated with the production efficiency of EBN farming,perhaps because extensive forest could help swiftlets to collect food and build nests.Conversely,while EBN farming is a sustainable and profitable option,the initial costs of constructing buildings to house swiftlets may deter farmers from participating in the process.