Characterization of a USDA Kentucky Bluegrass (Poa pratensis L.) Core Collection for Reproductive Mode and DNA Content by Flow Cytometry

Kentucky bluegrass (Poa pratensis L.) is an important turf and forage grass species with a facultative apomictic breeding behavior. In this study, mature seed and leaf tissue from 38 accessions of a USDA core collection of Kentucky bluegrass were analyzed with flow cytometry to characterize the reproductive mode and DNA content for each accession. Major reproductive pathways for each accession were determined based upon the presence and the position of the peaks observed and the known methods of reproduction for Kentucky bluegrass. While the majority of the accessions exhibited facultative apomictic reproductive behavior with a combination of reduced, zygotic and unreduced, parthenogenic embryo production, obligate sexual or obligate apomictic accessions were also found to be present in this core collection. In addition, reduced, parthenogenic and unreduced zygotic embryos were also detected in several accessions. Flow cytometric analysis of somatic tissue revealed a large range of DNA variation within this core collection. We also examined the sensitivity of flow cytometry in analyzing bulked samples containing a large number of plants with varied DNA content and determined that flow cytometry can effectively detect a plant having a different DNA content within a 15-plant bulk sample. Overall the combination of mature seed and somatic tissue analysis generated important information for the Kentucky bluegrass core collection and can be an effective and affordable tool to characterize even greater numbers of Kentucky bluegrass accessions.     

草地早熟禾高产农艺措施数学模型与优化指标的研究

采用二次回归正交组合设计方法,对草地早熟禾在三江源地区"黑土型"退化草地上的高产配套栽培技术进行了研究,建立了草地早熟禾高产数学模型,解析了试验因素的产量效应及其交互作用,并优选出了最佳农艺措施组合方案,确定了置信区间,为其高产栽培提供参考依据.     

Performance of Timothy-based Grass/Legume Mixtures in Cold Winter Region

This study sought to identify grass/legume mixtures that increase the yield and persistence of forage stands with improved nutritive quality in cold‐winter regions, compared with the standard mixture of timothy (Phleum pratense L.)/red clover (Trifolium pratense L.)/alsike clover (Trifolium hybridum L.). Timothy was mixed with either perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis L.) or Kentucky bluegrass (Poa pratensis L.). The legumes in mixtures were red clover, alfalfa (Medicago sativa L.) or white clover (Trifolium repens L.). Averaged over three production years, the majority of mixtures had greater dry matter (DM) yields than the standard (8.35 t ha^?1). Timothy, grown alone and in three mixtures, outyielded the standard by 19–30 %. Yield reductions in mixtures over the 3‐year period were greatest with red clover, and least with bluegrass. Mixtures with alfalfa were highest in nitrogen (28.4 g kg^?1), while grasses grown alone (24.6 g kg^?1) and the standard mixture (25.1 g kg^?1) were the lowest in N. Mixtures with red clover or alfalfa had the least neutral detergent fibre (NDF), averaging 418 and 429 g kg^?1 respectively. Mixtures including white clover were initially low in NDF at 347 g kg^?1 in year 1 but increased to 550 g kg^?1 in year 3 as white clover composition declined in the sward.     

青海野生草地早熟禾响应干旱胁迫的代谢通路及转录调控分析

为探究青海野生草地早熟禾（Poa pratensis）响应干旱胁迫的分子机制,本研究以青海野生草地早熟禾抗旱材料‘10-202’和敏感材料‘09-61’为研究对象,采用高通量Illumina Hiseq测序技术对15% PEG-6000模拟的干旱胁迫和正常处理下的2份材料的叶片进行差异基因表达分析。结果表明：‘10-202’处理间存在3 166个差异表达基因（Different expression genes,DEGs）,上调和下调表达基因数目分别为1 979和1 187个;‘09-61’处理间共有314个DEGs,上调表达的有64个,下调表达的有250个。京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes,KEGG）富集分析发现,2份材料的差异基因均显著富集在淀粉和蔗糖代谢通路。运用MapMan软件对‘10-202’干旱胁迫下与转录调控相关的差异基因进行了功能注释,发现bHLH,AP2/EREPB及C2H2锌指家族转录因子在响应干旱胁迫中发挥着重要作用。本研究为后续挖掘草地早熟禾耐旱相关候选基因的克隆和功能验证奠定了理论基础。     

平衡施肥对多年生禾本科牧草产量的影响

在青海同德地区选取5龄同德老芒麦（Elymus sibiricus cv.Tongde）和5龄青海冷地早熟禾（Poa crymophilacv.Qinghai）人工草地连续两年进行了老龄人工草地平衡施肥试验。试验根据国际植物营养研究所（IPNI）中国项目部提供的测土施肥最佳配方（OPT）设6个施肥处理,另设一个不施肥对照,测量两种牧草品种的草产量及种子产量。结果施氮肥的经济效益高于施磷肥的效益,同德老芒麦的施肥效益高于冷地早熟禾的施肥效益,两种牧草平均草产量和种子产量以OPT-P施肥处理时为最高,分别为8946.2kg/hm2和368.1kg/hm2.氮磷肥互作产生负效应。施钾无显著增产作用。     

早熟禾属植物种间关系的RAPD分析

利用随机扩增多态性DNA（RAPD）技术对10种早熟禾植物进行了基因组DNA多态性分析，对30个OPRON公司十聚体随机引物进行多态性筛选，28个可产生多态性，18个引物产生的250个DNA片段，用于计算种间的欧氏遗传相似性系数分析，在Statistic统计软件按非加权算术平均数（UPGMA）进行聚类并构建系统发育树状图，结果，10种早熟禾植物种间的亲缘关系，其变幅主要在6．7－8．5之间；其中P.botryoides与P.psilolepis之间的遗传距离最小，为6．7，其次是P.sinattenuata与P.sphondylodes遗传距离较近，为6．8，而P．sikkimensis与P.pratensis,P.sikkimensis与P.psilolepis之间的距离最远，均为10．5，这与形态学分类结果基本一致，说明RAPD分析方法可从分子生物学角度为早熟禾属植物的系统学分类提供更为有利和可靠的证据。     

早熟禾与假俭草间植草坪效果观察

为解决长沙市历年来草坪青绿期短的问题，在进行多年草坪引种的基础上，根据早熟禾苗温耐寒怕热，在长沙地区７－１０月地面枯黄，１１－６月生长青绿；假俭草抗寒性能差，耐热性能好，在５－１０月生长青，１１－４月地面部分枯黄的生长习性，为了延长草坪的青绿期，提高园林价值，降低草坪建植费用，我们用上述二种草进行间植建坪试验，结果：草坪的年青绿期由单一早熟禾２００ｄ左右增加到３３０ｄ，吸滞留灰尘量由单一早熟禾每平     

早熟禾属不同种及生态型POD同功酶分析

采用聚丙烯酰胺垂直平板凝胶电泳技术，对７种（共８份）野生早熟禾属植物进行ＰＯＤ同功酶分析。结果表明：（１）８份材料的酶谱从负极至正极共出现了１３条酶带（Ｐｅｒ－Ａ ｔｏ Ｐｅｒ－Ｍ区）。（２）各种间酶谱差异明显，其中草地早熟禾和早熟禾酶带数最多，各有６条；硬质早熟禾最少，仅有３条。（３）每种早熟禾都有自己特定的标志带，可以用来比较鉴定。（４）同一种的不同生态型的酶谱完全相同，但它们在酶的含量和吸收     

植物生长延缓剂对草坪草生长发育的影响

[目的]为了研究美国研制生产的植物生长延缓剂Proxy对草坪草生长发育的影响。[方法]以冷季型草坪草高羊茅和草地早熟禾为试验材料,盆栽试验设低浓度Proxy、中浓度Proxy、高浓度Proxy和清水(CK)4个处理,研究不同浓度Proxy在我国北方气候条件下对草坪草株高、草屑量和生长格局的影响。[结果]中、高浓度Proxy处理显著降低了草地早熟禾的株高和草屑量,而对高羊茅株高和草屑量影响不显著。中、高浓度Proxy处理使草地早熟禾的生长格局发生了明显变化,如抑制垂直生长、加速横向生长、叶片变短增厚等,草坪质量明显改善,而低浓度处理效果不明显。Proxy各浓度处理对高羊茅生长格局影响不明显。[结论]该研究为我国北方草坪草生长的合理调控提供了理论依据。     

四种草地早熟禾抗盐碱生理生化特性的研究

对北方草坪建植中常用的4个草地早熟禾(PoaPratensis)品种进行了萌发期及苗期耐盐碱能力的比较研究。结果表明:低浓度混合盐碱处理对草地早熟禾的萌发和生长起到促进作用;随混合盐碱浓度的升高草地早熟禾的发芽率和生长受到明显的抑制,且对胚根生长的抑制作用强于胚芽;对幼苗进行混合盐碱胁迫发现,低浓度盐碱胁迫使SOD、CAT和POD的活性以及游离脯氨酸含量均升高,且在中等浓度下达到最高值,高浓度处理则开始下降;随着盐碱处理浓度的增大,MDA的含量也在缓慢增加。综合分析表明,四个草地早熟禾品种耐盐碱能力依次为:午夜>巴林>巴润>优异。