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
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
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 karyotypes of 27 individuals of Elymus nutans from eight wild populations in the Qinghai Plateau were analyzed using sequential FISH and GISH. High FISH pattern polymorphism and karyotype variation were detected w...The karyotypes of 27 individuals of Elymus nutans from eight wild populations in the Qinghai Plateau were analyzed using sequential FISH and GISH. High FISH pattern polymorphism and karyotype variation were detected within and among populations. The chromosome variations were mainly characterized as repeat deletions and amplifications along with inter-genomic translocations. The chromosomes of the St and Y genomes demonstrated higher polymorphism than those of the H genome. Six different intergenomic translocations were identified in 33.3% of individuals; type Ⅰ and Ⅱ translocations were detected with higher frequency. Further analysis revealed that type Ⅰ and Ⅱ translocations were distributed in different geographic regions. The origin of high karyotype variation of E. nutans in the Qinghai plateau is further discussed.展开更多
[ Objective] This study was to explore the inheritance of BC1 F3 to excellent characteristics of parents（ Elymus dahuricus, Hordeum brevisubu/atum）, heterosis and fertility restoration. E Methodl The agronomic chara...[ Objective] This study was to explore the inheritance of BC1 F3 to excellent characteristics of parents（ Elymus dahuricus, Hordeum brevisubu/atum）, heterosis and fertility restoration. E Methodl The agronomic characters such as growth period, growth rate, pollen fertility, fecundity, reproducibility and fresh grass output of Elymus dahudcus, Hordeum brevisubu/atum and BC1 F3 were comparatively studied. E Result l The growth dynamic of the BC1 F3 lined tended to like that of its parent Hordeum brevisubu/atum; although growing periods of various lines were different, they were close to that of Hordeurn brevisubulatum. There were differences in pollen fertility and seed setting, the pollen fertility rate of YF3-93 was higher than recurrent parent Hordeum brevisubulatum, its seed setting rate in open pollination was also higher. Some lines had low pollen fertility rate and seed setting rate, such as the pollen fertility rate of PF3-52. There were significant differences in the output among BC1 F3 lines, e.g. the heterosis （HP） of YF3-64, YF3-74 and YF3-83 were 75.53%, 75.12% and 66.16%, respectively; however, the yields of PF3- 52, PF3-15 and PF3-42 were lower than their parents. ~ Conclusion] This study provided reference for breeding new varieties of forage which is suitable to drought and saline environment.展开更多
Potentilla anserina L.and Elymus nutans Griseb.are dominant species in the subalpine meadows of China.Grazing is one of the most important factors that influence community structure and productivity of subalpine meado...Potentilla anserina L.and Elymus nutans Griseb.are dominant species in the subalpine meadows of China.Grazing is one of the most important factors that influence community structure and productivity of subalpine meadows.Understanding how grazing changes photosynthetic capability is essential for preservation and restoration of grasslands.However,information about the effects of grazing on photosynthetic capability remains inadequate.Experiments were conducted in fencing and grazing areas in the Qilian Mountains,Northwest China.The leaf gas exchange and photosynthetic curves of P.anserina and E.nutans were measured at different growth stages.Results showed that grazing decreased the values of leaf gas exchange parameters,such as net photosynthetic rate,stomatal conductance,transpiration rate,and intercellular CO2 concentration of P.anserina and E.nutans.In addition,grazing decreased the values of net photosynthetic rate-photosynthetically active radiation(PN-PAR)curve parameters,such as light-saturated net photosynthetic rate,apparent quantum efficiency,light compensation point,light saturation point,and dark respiration rate.Our results demonstrated that grazing was the primary limiting factor for photosynthesis of dominant grassland species in the study area.展开更多
The non-rectangular hyperbola(NRH)equation is the most popular method that plots the photosynthetic light-response(PLR)curve and helps to identify plant photosynthetic capability.However,the PLR curve can't be plo...The non-rectangular hyperbola(NRH)equation is the most popular method that plots the photosynthetic light-response(PLR)curve and helps to identify plant photosynthetic capability.However,the PLR curve can't be plotted well by the NRH equation at different plant growth phases due to the variations of plant development.Recently,plant physiological parameters have been considered into the NRH equation to establish the modified NRH equation,but plant height(H),an important parameter in plant growth phases,is not taken into account.In this study,H was incorporated into the NRH equation to establish the modified NRH equation,which could be used to estimate photosynthetic capability of herbage at different growth phases.To explore photosynthetic capability of herbage,we selected the dominant herbage species Potentilla anserina L.and Elymus nutans Griseb.in the Heihe River Basin,Northwest China as the research materials.Totally,twenty-four PLR curves and H at different growth phases were measured during the growing season in 2016.Results showed that the maximum net photosynthetic rate and the initial slope of PLR curve linearly increased with H.The modified NRH equation,which is established by introducing H and an H-based adjustment factor into the NRH equation,described better the PLR curves of P.anserina and E.nutans than the original ones.The results may provide an effective method to estimate the net primary productivity of grasslands in the study area.展开更多
A molecular cytogenetic investigation was conducted on plants of the allohexaploid species Elymus nutans with varying fertility on the Qinghai-Tibet Plateau.Molecular karyotyping revealed that chromosome variants were...A molecular cytogenetic investigation was conducted on plants of the allohexaploid species Elymus nutans with varying fertility on the Qinghai-Tibet Plateau.Molecular karyotyping revealed that chromosome variants were distributed unevenly among genomes and among different homologue chromosomes in each genome.The plants with varying fertility exhibited significantly higher numbers of chromosome variants than did the normal fertility samples,although both kinds of plants showed the same pattern of high-to-low polymorphism from the Y to St and H genomes.Heterozygosis and karyotype heterozygosity in the plants with varying fertility were 3-and 13-fold higher than those in normal samples,respectively.Significant negative correlations were found not only between seed setting rates and total genome heterozygosity but also between seed setting rates and heterozygosity of each genome in the plants of varying fertility.Chromosome pairing analysis was performed using genomic in situ hybridization in selected plants of different fertility levels.The pairing of chromosomes at meiotic metaphase I was mostly bivalent,although univalent,trivalent,quadrivalent,and other polyvalents also occurred;in addition,chromosome configuration forms and frequencies varied among the studied samples.ANOVA results showed that the average number of ring bivalents in the Y genome was significantly higher than those in the St and H genomes.Significant positive correlations between pollen grain fertility and ring bivalent number were found in the St and H genomes but not in the Y genome.Furthermore,chromosome configuration parameters(total bivalents,numbers of ring and rod bivalents)were found to be significantly correlated with heterozygosity and seed setting rates in the St and H genomes,respectively,but not in the Y genome.It was inferred that the seed setting rate and pollen grain fertility in E.nutans are strongly influenced by the heterozygosity of each genome,but the Y genome differs from the St and H genomes due to chromosome pair alterations.The St and H genomes may contain more chromosome structural variations than the Y genome in E.nutans.展开更多
Wild native Elymus(Elymus dahuricus)is one of the most important and valuable forage grass on Qinghai-Tibetan Plateau(QTP)pasture of China.It mainly distributes above sea-level of 1700 to 3000 m on the QTP.The objecti...Wild native Elymus(Elymus dahuricus)is one of the most important and valuable forage grass on Qinghai-Tibetan Plateau(QTP)pasture of China.It mainly distributes above sea-level of 1700 to 3000 m on the QTP.The objective of this study was to investigate how the nutritive composition of Elymus responsed to the changes of altitude in local environments.Two test sites located at Minghe and Huangzhong counties,in which four sampling plots were arranged with sea levels of 1714,1872,2097 and 2185 m in Minhe County,while other four in Huangzhong County were with sea-level of 2560,2613,2668 and 2775 m.The whole plants of Elymus during anthesis stage were collected from all the plots for determining the indexes of crude protein(CP),crude fat(CF),neutral detergent fiber(NDF),acid detergent fiber(ADF),crude ash(ASH),calcium(Ca)and phosphorus(P).The results showed that the content of CP,crude ash and Ca changed irregularly corresponding to the altitude in the two counties,but significant higher with CP(1.09%),Ash(0.33%)and Ca(0.34%)in the low altitude areas(1714-2185 m)than those in the high altitude areas.NDF and ADF in the low altitude areas were significantly lower by 5.35% and 2.61% compared with those in the high altitude areas.There was no significant difference of CF as well as P in plant from different altitudes.Comprehensive evaluation revealed that superior nutritional composition of Elymus dahuricus presented at the sampling plots of altitude of 1714 m in Minhe County.展开更多
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.
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.
基金supported by the National Natural Science Foundation of Qinghai Province (2015-ZJ-903)the National Natural Science Foundation of China (31072075)
文摘The karyotypes of 27 individuals of Elymus nutans from eight wild populations in the Qinghai Plateau were analyzed using sequential FISH and GISH. High FISH pattern polymorphism and karyotype variation were detected within and among populations. The chromosome variations were mainly characterized as repeat deletions and amplifications along with inter-genomic translocations. The chromosomes of the St and Y genomes demonstrated higher polymorphism than those of the H genome. Six different intergenomic translocations were identified in 33.3% of individuals; type Ⅰ and Ⅱ translocations were detected with higher frequency. Further analysis revealed that type Ⅰ and Ⅱ translocations were distributed in different geographic regions. The origin of high karyotype variation of E. nutans in the Qinghai plateau is further discussed.
文摘[ Objective] This study was to explore the inheritance of BC1 F3 to excellent characteristics of parents（ Elymus dahuricus, Hordeum brevisubu/atum）, heterosis and fertility restoration. E Methodl The agronomic characters such as growth period, growth rate, pollen fertility, fecundity, reproducibility and fresh grass output of Elymus dahudcus, Hordeum brevisubu/atum and BC1 F3 were comparatively studied. E Result l The growth dynamic of the BC1 F3 lined tended to like that of its parent Hordeum brevisubu/atum; although growing periods of various lines were different, they were close to that of Hordeurn brevisubulatum. There were differences in pollen fertility and seed setting, the pollen fertility rate of YF3-93 was higher than recurrent parent Hordeum brevisubulatum, its seed setting rate in open pollination was also higher. Some lines had low pollen fertility rate and seed setting rate, such as the pollen fertility rate of PF3-52. There were significant differences in the output among BC1 F3 lines, e.g. the heterosis （HP） of YF3-64, YF3-74 and YF3-83 were 75.53%, 75.12% and 66.16%, respectively; however, the yields of PF3- 52, PF3-15 and PF3-42 were lower than their parents. ~ Conclusion] This study provided reference for breeding new varieties of forage which is suitable to drought and saline environment.
基金financially supported by the National Natural Science Foundation of China(91025015,51178209)the Project of Arid Meteorological Science Research Foundation of China Meteorological Administration(IAM201608)
文摘Potentilla anserina L.and Elymus nutans Griseb.are dominant species in the subalpine meadows of China.Grazing is one of the most important factors that influence community structure and productivity of subalpine meadows.Understanding how grazing changes photosynthetic capability is essential for preservation and restoration of grasslands.However,information about the effects of grazing on photosynthetic capability remains inadequate.Experiments were conducted in fencing and grazing areas in the Qilian Mountains,Northwest China.The leaf gas exchange and photosynthetic curves of P.anserina and E.nutans were measured at different growth stages.Results showed that grazing decreased the values of leaf gas exchange parameters,such as net photosynthetic rate,stomatal conductance,transpiration rate,and intercellular CO2 concentration of P.anserina and E.nutans.In addition,grazing decreased the values of net photosynthetic rate-photosynthetically active radiation(PN-PAR)curve parameters,such as light-saturated net photosynthetic rate,apparent quantum efficiency,light compensation point,light saturation point,and dark respiration rate.Our results demonstrated that grazing was the primary limiting factor for photosynthesis of dominant grassland species in the study area.
基金funded by the National Natural Science Foundation of China(91025015,51178209)the Project of Arid Meteorological Science Research Foundation of China Meteorological Administration(IAM201608)
文摘The non-rectangular hyperbola(NRH)equation is the most popular method that plots the photosynthetic light-response(PLR)curve and helps to identify plant photosynthetic capability.However,the PLR curve can't be plotted well by the NRH equation at different plant growth phases due to the variations of plant development.Recently,plant physiological parameters have been considered into the NRH equation to establish the modified NRH equation,but plant height(H),an important parameter in plant growth phases,is not taken into account.In this study,H was incorporated into the NRH equation to establish the modified NRH equation,which could be used to estimate photosynthetic capability of herbage at different growth phases.To explore photosynthetic capability of herbage,we selected the dominant herbage species Potentilla anserina L.and Elymus nutans Griseb.in the Heihe River Basin,Northwest China as the research materials.Totally,twenty-four PLR curves and H at different growth phases were measured during the growing season in 2016.Results showed that the maximum net photosynthetic rate and the initial slope of PLR curve linearly increased with H.The modified NRH equation,which is established by introducing H and an H-based adjustment factor into the NRH equation,described better the PLR curves of P.anserina and E.nutans than the original ones.The results may provide an effective method to estimate the net primary productivity of grasslands in the study area.
基金the Natural Science Foundation of Qinghai Province,China(2020-ZJ-914)the Second Tibet Plateau Scientific Expedition and Research(STEP)Program(Grant No.2019QZKK0303).
文摘A molecular cytogenetic investigation was conducted on plants of the allohexaploid species Elymus nutans with varying fertility on the Qinghai-Tibet Plateau.Molecular karyotyping revealed that chromosome variants were distributed unevenly among genomes and among different homologue chromosomes in each genome.The plants with varying fertility exhibited significantly higher numbers of chromosome variants than did the normal fertility samples,although both kinds of plants showed the same pattern of high-to-low polymorphism from the Y to St and H genomes.Heterozygosis and karyotype heterozygosity in the plants with varying fertility were 3-and 13-fold higher than those in normal samples,respectively.Significant negative correlations were found not only between seed setting rates and total genome heterozygosity but also between seed setting rates and heterozygosity of each genome in the plants of varying fertility.Chromosome pairing analysis was performed using genomic in situ hybridization in selected plants of different fertility levels.The pairing of chromosomes at meiotic metaphase I was mostly bivalent,although univalent,trivalent,quadrivalent,and other polyvalents also occurred;in addition,chromosome configuration forms and frequencies varied among the studied samples.ANOVA results showed that the average number of ring bivalents in the Y genome was significantly higher than those in the St and H genomes.Significant positive correlations between pollen grain fertility and ring bivalent number were found in the St and H genomes but not in the Y genome.Furthermore,chromosome configuration parameters(total bivalents,numbers of ring and rod bivalents)were found to be significantly correlated with heterozygosity and seed setting rates in the St and H genomes,respectively,but not in the Y genome.It was inferred that the seed setting rate and pollen grain fertility in E.nutans are strongly influenced by the heterozygosity of each genome,but the Y genome differs from the St and H genomes due to chromosome pair alterations.The St and H genomes may contain more chromosome structural variations than the Y genome in E.nutans.
基金Supported by the National Natural Science Foundation Project(31472145)
文摘Wild native Elymus(Elymus dahuricus)is one of the most important and valuable forage grass on Qinghai-Tibetan Plateau(QTP)pasture of China.It mainly distributes above sea-level of 1700 to 3000 m on the QTP.The objective of this study was to investigate how the nutritive composition of Elymus responsed to the changes of altitude in local environments.Two test sites located at Minghe and Huangzhong counties,in which four sampling plots were arranged with sea levels of 1714,1872,2097 and 2185 m in Minhe County,while other four in Huangzhong County were with sea-level of 2560,2613,2668 and 2775 m.The whole plants of Elymus during anthesis stage were collected from all the plots for determining the indexes of crude protein(CP),crude fat(CF),neutral detergent fiber(NDF),acid detergent fiber(ADF),crude ash(ASH),calcium(Ca)and phosphorus(P).The results showed that the content of CP,crude ash and Ca changed irregularly corresponding to the altitude in the two counties,but significant higher with CP(1.09%),Ash(0.33%)and Ca(0.34%)in the low altitude areas(1714-2185 m)than those in the high altitude areas.NDF and ADF in the low altitude areas were significantly lower by 5.35% and 2.61% compared with those in the high altitude areas.There was no significant difference of CF as well as P in plant from different altitudes.Comprehensive evaluation revealed that superior nutritional composition of Elymus dahuricus presented at the sampling plots of altitude of 1714 m in Minhe County.
