The Combination of Achnatherum inebrians Extracts and Soil Microorganisms Inhibited Seed Germination and Seedling Growth in Elymus nutans

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.

3种披碱草属(Elymus)牧草交配系统研究

通过测定3种披碱草属（Elymus）牧草,即老芒麦（E.sibiricus）、麦薲草（E.tangutorum）和披碱草（E.dahuricus）的花粉-胚珠比（P/O值）、杂交指数（OCI）,结合不同授粉方式下这3种牧草的结实率,探讨这3种披碱草属牧草的交配系统,为披碱草属牧草杂交育种、丰产栽培等提供理论依据。结果表明,这3种牧草的花粉-胚珠比（P/O值）均介于31.9~396.0之间,交配系统属于兼性自交;杂交指数OCI值均为2,交配系统也属于兼性自交;结实率统计表明,以自交为主,异交可育。因此,这3种披碱草属牧草的交配系统属于兼性自交类型。

普通小麦与Elymus rectisetus异附加系的分子细胞遗传学鉴定

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。

Elymus wawawaiensis编码乙酰辅酶A羧化酶Acc-1基因序列的分析及系统学意义

质体乙酰辅酶A羧化酶(ACCase)催化长链脂肪酸的合成。编码小麦质体ACCase的基因(Acc-1)已用于一年生小麦的系统与进化研究,但还未有多年生物种相应的研究报道。本研究发现,Elymus wawawaiensis的Acc-1基因第8外显子和第7内含子与其他已知该序列相比除核苷酸替代外,多了176个碱基,从而与现有已知的一年生小麦相应序列有显著差异。在NCBI中对该序列和已报道的Acc-1基因相应序列blast比对后,结果表明与Hordeum vulgare Acc-1具有87.15%的最高相似性。以Panicum virgatum、Zea mays和Lolim rigidum为外类群,最大简约法(MP)和邻接法(NJ)对该基因和已报道的Acc-1基因分别构建系统进化树,其中E.wawawaiensis和H.vulgare形成一个分支,自展支持率100%。研究同时表明该基因在小麦族多年生物种系统与进化研究中有重要的应用前景。

普通小麦—Elymus rectisetus异附加系的特征特性研究

报道了对普通小麦Elymusrectisetus异附加系1026A1、1057A1和1035A2的细胞学、白粉病抗性、高分子量麦谷蛋白亚基组成和形态学性状的研究结果。细胞学鉴定表明,三种异附加系均为2n=22Ⅱ;1026A1、1057A1和1035A2的花粉母细胞减数分裂中期I染色体构型统计结果为2n=22Ⅱ的细胞分别占观察细胞总数的95.1%、97.0%和96.0%,表明3种异附加系具有良好的细胞学稳定性。小麦白粉病抗性鉴定结果表明,E.rectisetus品系1050表现免疫,异附加系和普通小麦亲本Fukuhokomugi高度感染白粉病。异附加系的高分子量麦谷蛋白亚基组成与Fukuhokomugi相同。此外,获得1026A1的形态学标记一个。

High molecular karyotype variation revealed in indigenous Elymus nutans in the Qinghai Plateau

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.

Leaf gas exchange and photosynthesis curves of Elymus nutans and Potentilla anserina under fencing and grazing conditions in the Qilian Mountains, Northwest China

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.

Modified non-rectangular hyperbola equation with plant height for photosynthetic light-response curves of Potentilla anserina and Elymus nutans at various growth phases in the Heihe River Basin, Northwest China

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.

Molecular cytogenetic study on the plants of Elymus nutans with varying fertility on the Qinghai-Tibet Plateau

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.

老芒麦Elymus Sibiricus L引种试验总结

川西北牧区解放后,牧业生产发展很快,有些地区牲畜头数增加两倍、三倍其至更多,使草场载畜量过重,饲草供不应求,成为牧业生产的限制因子。以若尔盖县两个国营牧场为例:向东牧场草场总面积13.43万亩,可利用面积8万亩,有大小牲畜11301头(只),折合羊单位20197只,每个羊单位有草场面积4亩;打更沟牧场草场总面积10万亩,可利用面积7万亩。有牲畜9059头(只),折合羊单位16892只,每个羊单位也只有草场面积4亩。

Influence of Altitude on Nutritional Compositions of Wild Native Elymus on Qinghai-Tibetan Plateau of China

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.

Effects of Altitude Change on Nutritional Quality and Elymus nutans Regularity in Qinghai-Tibet Plateau

In order to reveal the effects of different altitudes on the nutritional quality of wild forage in Qinghai-Tibet Plateau,this study used Elymus nutans as the tested plants to evaluate the changes of nutrient contents and the correlation between the nutrient contents and altitudes.Four sampling sites were set up at altitudes of 2562,2660,2775 and 2905 m with the vertical distance among each sampling point was about 100 m.The results showed that the crude protein,ash and phosphorus contents of Elymus nutans decreased significantly with an increase in altitudes.The crude protein contents decreased by 1.87%with each 100 m increase in altitudes.The variation rule of crude protein contents with altitudes in the simulated curve was"y=-0.0187x+63.244(R^(2)=0.9557)".The crude ash contents decreased by 1.77%with each 100 m increase in altitudes.The variation rule of crude ash contents with altitudes in the simulated curve was"y=-0.0177x+56.144(R^(2)=0.978)".Neutral detergent fiber(NDF)and acid detergent fiber(ADF)showed an overall increasing trend with the increase of altitudes,but the most obvious increase was at 2775 m.The contents of crude fat and Ca did not change regularly with altitudes.

Drought Resistance of Elymus sibiricus from Different Producing Areas at Seedlings Stage

[ Objective] To evaluate drought resistance of siberian wildrye （ Elymus sibiricus） from different producing areas. [ Method] Germplasm materials of siberian wildrye from Xinjiang （E01）, Gansu （E02）, Beijing （E03）, Shanxi （E04） and Qinghai （E05） were used as experimental materials and treated under continuous drought stress. The external morphology of their leaves was observed. On Day 0, 5 and 10, the dynamic variations of relative conductivity, malondialdehyde （MDA） content, chlorophyll content, soluble sugar content and proline content were determined. Subordinate function values analysis was performed to evaluate their drought resistance comprehensively. [ Result] Under continuous drought stress, the experimental siberian wildrye showed different extemal morphology of leaves. With increasing intensity and extending time of drought stress, the chlorophyll content increased significantly （P 〈 0.05）, and its differences between the siberian wildrye from different producing areas were significant （ P 〈 0.05） ; the relative electrical conductivity, malondialdehyde （MDA） content, soluble sugar content and proline content decreased significantly （P 〈 0.05）, and their differences between the siberian wildrye from different producing areas were significant （P 〈 0.05）. [Conclusion] The drought resistance of E04, E05, E01, E03 and E02 declines successively.

Effects of Epichloë endophyte on antioxidant enzymes activities, photosynthesis and growth of three ecotypes of Elymus dahuricus

Fungal endophytes of some cultivated grasses can increase plant performance and competitive abilities,especially under stress. Far less is known about the influence of Epichlo? infections in wild populations of wild grasses. In this study, plants of three Elymus dahuricus ecotypes(WLS, QY and WTS) either infected with Epichlo? endophyte(E+) or uninfected(E–) were grown in the field. The activities of the antioxidant enzymes ascorbate peroxidase, catalase, peroxidase and superoxide dismutase, and concentrations of H_2O_2 and malondialdehyde were examined in the leaves of E+ and E– plants. We also determined photosynthesis parameters,leaf blade and sheath carbohydrate concentration and plant growth parameters of both E+ and E– plants. E+ plants from the WLS and QY populations had significantly higher antioxidant enzyme activities and photosynthetic capability(P < 0.05), superior growth characteristics including more abundant carbohydrate concentration than E– plants. In contrast, in plants from the WTS population,the endophyte had no significant effect on reactive oxygen species scavenging capability and growth performance(P > 0.05), and even displayed some negative effects on plant photosynthetic capability. Thus, endophyte infection significantly affected E. dahuricus antioxidant enzyme activities(P < 0.05), photosynthesis and growth capability,although, the effects varied with plant ecotypes.

老芒麦花粉活力和柱头可授性及授粉方式研究

用TTC法测定了老芒麦(Elymus sibiricus L.)花粉的活力,用联苯胺-过氧化氢法测定了其柱头的可授性;采用套袋方法,进行自花、异花授粉及开放授粉方式下单穗结实率统计,探讨老芒麦的授粉方式。结果表明,盛花期后相应天数的花粉活力是早熟老芒麦>中熟老芒麦>晚熟老芒麦;花粉活力从最高到无,早熟老芒麦可持续6 d,中熟老芒麦和晚熟老芒麦可持续5 d。3种熟性的老芒麦在盛花期开始后的前2 d柱头可授性强;早熟老芒麦和中熟老芒麦的柱头从盛花期第一天开始直至第10天均有可授性,晚熟老芒麦的柱头从盛花期第一天开始至第八天均有可授性,因此老芒麦的最佳授粉期在盛花期第一至二天。老芒麦为自花授粉植物,具有一定的天然杂交率。

披碱草属6种牧草苗期抗旱性鉴定

对来自青海不同地区的披碱草属(Elymus)牧草进行连续干旱处理,观察牧草叶片外部的形态特征,并测定干旱处理第0、5、10天的细胞膜透性、丙二醛(MDA)含量、可溶性糖含量、脯氨酸含量和叶绿素含量,并运用隶属函数法综合评判其抗旱性。结果表明,随着干旱的胁迫,6种牧草的叶片叶绿素含量呈下降趋势;细胞膜透性、游离脯氨酸含量、可溶性糖含量及丙二醛含量均呈增加趋势,其中可溶性糖含量及丙二醛含量随着干旱程度的增加而显著增加(P<0.05)。综合评价得出6种牧草苗期对干旱胁迫的耐受性强弱顺序为:E04(贵南县茫拉乡)>E03(同德县谷芒乡)>E02(刚察县泉吉乡)>E01(达日县吉迈镇)>E05(天峻县新源镇)>E06(共和县倒淌河镇)。

我国野生披碱草属牧草居群的穗部形态多样性研究

对采集自我国12个不同分布区的105个野生披碱草属(Elymus)牧草居群的14项穗部形态指标进行研究,结果表明,我国披碱草属牧草种质资源穗部遗传多样性丰富,居群内多样性指数(H′)在0.784～1.652,平均多样性指数为1.396;居群总平均多样性指数为1.936,居群间表型分化系数为27.89%。14项穗部形态性状在居群内多样性、居群总多样性以及变异系数变化不完全一致,居群内H′最高的为旗叶与穗基部长度(1.648),居群总H′最高的为小穗长(2.054),变异系数最大的为第一颖芒长(58.932%),平均变异系数为31.22%,表明穗部形态性状均存在较大的变异,F检验差异极显著。引起居群形态差异的性状与种子产量密切相关,主要包括穗长、穗宽、第一颖芒长、第一外稃长、第一内稃长、第一外稃芒长、每穗轴小花数、第一颖长和第一颖宽。我国野生披碱草属牧草的多样性和分布格局是相关的,我国西北部是野生披碱草属牧草分布中心,也是披碱草属牧草的多样性中心。此外,提出了我国披碱草属牧草保护的策略。

披碱草焦磷酸化酶基因EdHP1的功能分析

氢离子焦磷酸化酶(H^+-PPase)是一类H^+转运蛋白,它以焦磷酸(PPi)水解底物,水解PPi产生的自由能与H^+跨膜转运相藕联,将细胞质中的H^+泵入液泡中,建立跨液泡膜电化学梯度,形成质子驱动力,为无机离子及其他溶质进出液泡提供动力,有利于植物维持细胞离子平衡和渗透平衡,增强植物的抗逆性。基于前期对披碱草(Elymus dahuricus)H^+-PPase基因Ed HP1克隆的基础,对其表达谱及基因功能进行了进一步研究。结果表明,通过Northern blot分析发现,该基因在披碱草中受干旱、低温非生物胁迫诱导表达。通过对转Ed HP1基因烟草在干旱、低温环境下的功能分析发现,过表达Ed HP1基因可以提高转基因烟草对干旱、冷胁迫的抗性。

Effect of mixture sowing on biomass allocation in the artificially-planted pastures, Southeastern Tibetan

Artificial planting is an important measure to promote the restoration of degraded grassland and protect the ecological environment. The objectives of the current study were to investigate the allocation pattern between aboveground biomass(AGB) and belowground biomass(BGB) in different seeding types of artificially-planted pastures. We explored the variation in biomass and the relationship between above-and belowground biomass in four artificiallyplanted pastures with one species from Elymus nutans Griseb(EN, perennial), Elymus sibiricus Linn(ES, perennial), Medicago sativa Linn(MS, perennial), and Avena sativa Linn(AS, annual) and in six artificially-planted communities with mixtures of two species by seeding ratio 1:1 from the abovementioned grasses(EN + AS, MS + AS, EN + ES, MS + EN, MS + ES, AS + ES) in 2015 and 2016. The results showed that E. nutans is the most productive species with the highest biomass production among the single crops. MS + ES was the most productive group in 2015, while the group with the highest biomass production changed to AS + ES in 2016. AGB was positively correlated to BGB in the surface soil layer in the first year, but positively related to BGB in the subsoil layer in the second year. In the early stageof artificial grassland succession, plants allocated more biomass to aboveground parts, with a root to shoot(R/S) ratio of 1.98. The slope of the log-log relationship between AGB and BGB was 1.07 in 2016, which is consistent with the isometric theory. Different sowing patterns strongly affected the accumulation and allocation of biomass in artificiallyplanted grassland, E. sibiricus was the suitable plant in the alpine regions, which will be conducive to understanding vegetation restoration and plant interactions in the future.

Competition of Squirreltail with Cheatgrass at Three Nitrogen Levels

Squirreltail (Elymus elymoides [Raf] Swezey) can grow in cheatgrass (Bromus tectorum L.) stands, and has reduced the biomass production of cheatgrass in its immediate vicinity. A field experiment was conducted to determine: 1) if competition for nitrogen resources occurs between seedlings of squirreltail and seedlings of cheatgrass, under low, medium, and high nitrogen levels, and;2) if competition for nitrogen resources in the seedling stage is a mechanism that allows squirreltail to establish in cheatgrass stands. Five accessions of squirreltail were each seeded with a single accession of cheatgrass in a cultivated field near Ephraim, Utah in the fall of 1995 and again in 1996. A completely randomized strip-plot design with 3 replications was used including the 5 joint seedings as well as pure seedings of each accession of both species. Three nitrogen levels representing high, medium (control), and low were applied. The study was replicated over 2 years in different areas of the same field. Harvests of above-ground biomass of squirreltail and cheatgrass within each treatment were conducted in July of 1996 and 1997. Using biomass production as a measure of efficient nitrogen use, cheatgrass competed for and used nitrogen resources more efficiently than squirreltail when nitrogen was not limiting. All squirreltail accessions were able to compete for and use nitrogen more efficiently than cheatgrass when there was low availability of nitrogen. Some accessions of squirreltail competed for nitrogen resources more efficiently than others both in the control and at the reduced nitrogen level. White Rocks and Sublette squirreltail accessions were the best competitors with cheatgrass at the low nitrogen level reducing the cheatgrasss biomass by as much as 75% and 67% respectively. An intermediate competitor with cheatgrass was the Gunnison accession. The Washakie and Pueblo accessions were poor competitors with cheatgrass at low nitrogen levels.