Elymus duthiei(Melderis)G.Singh,newly recorded from Xizang,China,is described and illustrated in detail.Morphologically,the species is similar to E.anthosachnoides(Keng)Á.Löve ex B.R.Lu and E.glaberrimus(Ken...Elymus duthiei(Melderis)G.Singh,newly recorded from Xizang,China,is described and illustrated in detail.Morphologically,the species is similar to E.anthosachnoides(Keng)Á.Löve ex B.R.Lu and E.glaberrimus(Keng&S.L.Chen)S.L.Chen but differs from the former in height and diameter of culms,number of nodes,width of leaf blades,and type of trichome and size of spikelets,and from the latter in distribution,height of culms,type of trichome of spikelets,and awn length.Detailed photo plates,descriptions,and distribution data are provided.展开更多
The dominant plant litter plays a crucial role in carbon(C)and nutrients cycling as well as ecosystem functions maintenance on the Qinghai-Tibet Plateau(QTP).The impact of litter decomposition of dominant plants on ed...The dominant plant litter plays a crucial role in carbon(C)and nutrients cycling as well as ecosystem functions maintenance on the Qinghai-Tibet Plateau(QTP).The impact of litter decomposition of dominant plants on edaphic parameters and grassland productivity has been extensively studied,while its decomposition processes and relevant mechanisms in this area remain poorly understood.We conducted a three-year litter decomposition experiment in the Gansu Gannan Grassland Ecosystem National Observation and Research Station,an alpine meadow ecosystem on the QTP,to investigate changes in litter enzyme activities and bacterial and fungal communities,and clarify how these critical factors regulated the decomposition of dominant plant Elymus nutans(E.nutans)litter.The results showed that cellulose and hemicellulose,which accounted for 95%of the initial lignocellulose content,were the main components in E.nutans litter decomposition.The litter enzyme activities ofβ-1,4-glucosidase(BG),β-1,4-xylosidase(BX),andβ-D-cellobiosidase(CBH)decreased with decomposition while acid phosphatase,leucine aminopeptidase,and phenol oxidase increased with decomposition.We found that both litter bacterial and fungal communities changed significantly with decomposition.Furthermore,bacterial communities shifted from copiotrophic-dominated to oligotrophic-dominated in the late stage of litter decomposition.Partial least squares path model revealed that the decomposition of E.nutans litter was mainly driven by bacterial communities and their secreted enzymes.Bacteroidota and Proteobacteria were important producers of enzymes BG,BX,and CBH,and their relative abundances were tightly positively related to the content of cellulose and hemicellulose,indicating that Bacteroidota and Proteobacteria are the main bacterial taxa of the decomposition of E.nutans litter.In conclusion,this study demonstrates that bacterial communities are the main driving forces behind the decomposition of E.nutans litter,highlighting the vital roles of bacterial communities in affecting the ecosystem functions of the QTP by regulating dominant plant litter decomposition.展开更多
In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts f...In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts from aboveground and belowground parts of A.inebrians significantly inhibited the germination rate,germination potential,germination index,vigor index,seedling height,root length,and fresh weight of E.nutans,but increased malondialdehyde content,catalase,peroxidase and superoxide dismutase activity of E.nutans seedlings(p<0.05).The allelopathy of aqueous extracts of the aboveground parts of A.inebrians was stronger than that of the pre-cipitates.Aqueous extracts of the aboveground parts of A.inebrians decreased seed germination rate,germination potential,germination index,vigor index,seedling length,root length,and seedling fresh weight by 10.45%-74.63%,24.18%-32.50%,19.03%-73.36%,37.83%-88.41%,21.42%-53.14%,2.65%-40.21%,and 20.45%-61.36%,respectively,and malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity increased by 8.09%-62.24%,27.83%-86.47%,22.90%-93.17%,and 11.15%-75.91%,respectively.The above indexes were higher in live soil than in sterilized soil.Soil microorganisms increased the allelopathy of A.inebrians.The seed germination rate,germination potential,germination index,vigor index,seedling length,and seedling fresh weight of E.nutans planted in live soil decreased by 8.22%-48.48%,10.00%-51.85%,8.19%-53.26%,16.43%-60.03%,12.91%-28.81%,and 9.09%-22.86%compared with sterilized soil,respectively.Malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity of E.nutans planted in live soil increased by 53.91%-81.06%,15.71%-57.34%,33.33%-86.31%,and 9.78%-52.51%compared with sterilized soil,respectively.The existence of soil microorganisms enhanced the allelopathy of the secondary metabolites of A.inebrians.A combination of microorganisms and aqueous extracts from the aboveground parts of A.inebrians had the strongest allelopathic effect on E.nutans.展开更多
Elymus rectisetus(Nees in Lehm)A.Lo..veetConnor是目前小麦族中发现的唯一的无融合生殖种,为了鉴定和标记从普通小麦与E.rectisetusBC2F2衍生后代中选育的2n=44株系1026A1、1057A1和1035A2的外源染色体,应用细胞学、基因组原位杂交和...Elymus rectisetus(Nees in Lehm)A.Lo..veetConnor是目前小麦族中发现的唯一的无融合生殖种,为了鉴定和标记从普通小麦与E.rectisetusBC2F2衍生后代中选育的2n=44株系1026A1、1057A1和1035A2的外源染色体,应用细胞学、基因组原位杂交和RAPD方法进行了研究。经细胞学鉴定,3个株系花粉母细胞减数分裂中期Ⅰ(PMC MⅠ)染色体构型均为2n=22Ⅱ,与普通小麦Fukuhokomugi杂交F1的PMC MⅠ染色体构型均为2n=21Ⅱ+1Ⅰ,两两杂交F1的PMC MⅠ染色体构型均为2n=21Ⅱ+2Ⅰ,表明它们是分别附加了1对互不相同外源染色体的普通小麦-E.rectisetus二体异附加系。标记E.rectisetus品系1050的基因组DNA为探针DNA,对3个异附加系进行原位杂交,分别鉴定出附加的1对E.rectisetus染色体。应用13个引物对2个亲本和3个异附加系进行RAPD分析,获得了可分别用于检测1026A1和1057A1中所附加的E.rectisetus染色体遗传物质的分子标记OPB-14900bp、OPE-09750bp和OPB-141000bp。展开更多
The circumscriptions of sections Auganthus Pax ex Balf. f. and Ranunculoides Chen et C. M. Hu in the genus Primula L. have been controversial, due to the different treatments of P. filchnerae Knuth. W...The circumscriptions of sections Auganthus Pax ex Balf. f. and Ranunculoides Chen et C. M. Hu in the genus Primula L. have been controversial, due to the different treatments of P. filchnerae Knuth. We conducted a phylogenetic analysis using sequences from the ITS region of nuclear ribosomal DNA. All five species of these two sections and some representatives of other related sections were sampled. The ITS trees show that P. filchnerae could be convincingly placed in sect. Auganthus , together with P. sinensis Sabine ex Lindl. and P. rupestris Balf. f. et Farrer, whereas sect. Ranunculoides contains two species: P. cicutariifolia Pax and P. merrilliana Schltr. These two sections are distantly related and their association with other sections needs further studies. This study also demonstrated that ITS sequences would be a suitable marker for the reconstruction of Primula phylogeny.展开更多
文摘Elymus duthiei(Melderis)G.Singh,newly recorded from Xizang,China,is described and illustrated in detail.Morphologically,the species is similar to E.anthosachnoides(Keng)Á.Löve ex B.R.Lu and E.glaberrimus(Keng&S.L.Chen)S.L.Chen but differs from the former in height and diameter of culms,number of nodes,width of leaf blades,and type of trichome and size of spikelets,and from the latter in distribution,height of culms,type of trichome of spikelets,and awn length.Detailed photo plates,descriptions,and distribution data are provided.
基金funded by the National Natural Science Foundation of China(31870435)the European Union's Marie Sklodowska-Curie Action Postdoctoral Fellowship(101061660)the China Scholarship Council(202106180060).
文摘The dominant plant litter plays a crucial role in carbon(C)and nutrients cycling as well as ecosystem functions maintenance on the Qinghai-Tibet Plateau(QTP).The impact of litter decomposition of dominant plants on edaphic parameters and grassland productivity has been extensively studied,while its decomposition processes and relevant mechanisms in this area remain poorly understood.We conducted a three-year litter decomposition experiment in the Gansu Gannan Grassland Ecosystem National Observation and Research Station,an alpine meadow ecosystem on the QTP,to investigate changes in litter enzyme activities and bacterial and fungal communities,and clarify how these critical factors regulated the decomposition of dominant plant Elymus nutans(E.nutans)litter.The results showed that cellulose and hemicellulose,which accounted for 95%of the initial lignocellulose content,were the main components in E.nutans litter decomposition.The litter enzyme activities ofβ-1,4-glucosidase(BG),β-1,4-xylosidase(BX),andβ-D-cellobiosidase(CBH)decreased with decomposition while acid phosphatase,leucine aminopeptidase,and phenol oxidase increased with decomposition.We found that both litter bacterial and fungal communities changed significantly with decomposition.Furthermore,bacterial communities shifted from copiotrophic-dominated to oligotrophic-dominated in the late stage of litter decomposition.Partial least squares path model revealed that the decomposition of E.nutans litter was mainly driven by bacterial communities and their secreted enzymes.Bacteroidota and Proteobacteria were important producers of enzymes BG,BX,and CBH,and their relative abundances were tightly positively related to the content of cellulose and hemicellulose,indicating that Bacteroidota and Proteobacteria are the main bacterial taxa of the decomposition of E.nutans litter.In conclusion,this study demonstrates that bacterial communities are the main driving forces behind the decomposition of E.nutans litter,highlighting the vital roles of bacterial communities in affecting the ecosystem functions of the QTP by regulating dominant plant litter decomposition.
基金This work was supported by the Budgetary Project the Chinese Academy of Sciences Leads the Sub-Project of Class A Project(XDA26020202)the National“973”Program Project Topics(2014CB138702)+2 种基金the Basic Scientific Research Business Expenses of Central Universities(Lzujbky-2022-kb10)the 111 Wisdom Base(B12002)the Fundamental Research Funds for the Central Public Welfare Research Institutes(Chinese Academy of Forestry)(CAFYBB2021ZD001).
文摘In a greenhouse experiment,the effects of soil microorganisms and extracts of Achnatherum inebrians on the seed germination and seedling growth of Elymus nutans were studied.The results showed that both the extracts from aboveground and belowground parts of A.inebrians significantly inhibited the germination rate,germination potential,germination index,vigor index,seedling height,root length,and fresh weight of E.nutans,but increased malondialdehyde content,catalase,peroxidase and superoxide dismutase activity of E.nutans seedlings(p<0.05).The allelopathy of aqueous extracts of the aboveground parts of A.inebrians was stronger than that of the pre-cipitates.Aqueous extracts of the aboveground parts of A.inebrians decreased seed germination rate,germination potential,germination index,vigor index,seedling length,root length,and seedling fresh weight by 10.45%-74.63%,24.18%-32.50%,19.03%-73.36%,37.83%-88.41%,21.42%-53.14%,2.65%-40.21%,and 20.45%-61.36%,respectively,and malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity increased by 8.09%-62.24%,27.83%-86.47%,22.90%-93.17%,and 11.15%-75.91%,respectively.The above indexes were higher in live soil than in sterilized soil.Soil microorganisms increased the allelopathy of A.inebrians.The seed germination rate,germination potential,germination index,vigor index,seedling length,and seedling fresh weight of E.nutans planted in live soil decreased by 8.22%-48.48%,10.00%-51.85%,8.19%-53.26%,16.43%-60.03%,12.91%-28.81%,and 9.09%-22.86%compared with sterilized soil,respectively.Malondialdehyde content,peroxidase,catalase,and superoxide dismutase activity of E.nutans planted in live soil increased by 53.91%-81.06%,15.71%-57.34%,33.33%-86.31%,and 9.78%-52.51%compared with sterilized soil,respectively.The existence of soil microorganisms enhanced the allelopathy of the secondary metabolites of A.inebrians.A combination of microorganisms and aqueous extracts from the aboveground parts of A.inebrians had the strongest allelopathic effect on E.nutans.
文摘The circumscriptions of sections Auganthus Pax ex Balf. f. and Ranunculoides Chen et C. M. Hu in the genus Primula L. have been controversial, due to the different treatments of P. filchnerae Knuth. We conducted a phylogenetic analysis using sequences from the ITS region of nuclear ribosomal DNA. All five species of these two sections and some representatives of other related sections were sampled. The ITS trees show that P. filchnerae could be convincingly placed in sect. Auganthus , together with P. sinensis Sabine ex Lindl. and P. rupestris Balf. f. et Farrer, whereas sect. Ranunculoides contains two species: P. cicutariifolia Pax and P. merrilliana Schltr. These two sections are distantly related and their association with other sections needs further studies. This study also demonstrated that ITS sequences would be a suitable marker for the reconstruction of Primula phylogeny.
