青海草地早熟禾(Poa pratensis L.cv.Qinghai)近几年的研究进展

论述了青海草地早熟禾(Poa pratensis L.cv.Qinghai)野生栽培品种的由来,以及近几年在生物-生态性、恢复生态学、生理生化和高寒草坪方面的工作,提出了青海草地早熟禾目前依然缺乏的研究,指出今后工作的重点,应加强青藏高原育种工作,寻找更多更好的牧草生态型品种。

冷地型草坪草耐热机理初探——Ⅰ.草地早熟禾(Poa pratensis L.)在热境胁迫下叶片叶绿素含量和POD酶活性的变化

草地早熟禾在持续高温（37～38℃）胁迫下表现为叶绿素相对含量下降,POD酶活性在处理2d时表现为下降,4d及4d后则明显提高。耐热品种较不耐热品种的叶片POD酶活性无论是适温（25℃）还是高温（38℃）下一般均较高。热境下有较高的POD酶活性可能是植株体耐热的主要原因之一。

Genetic Relationships in Advanced Generation Hybrids Derived from Crosses between Texas (<i>Poa arachnifera</i>) and Kentucky (<i>Poa pratensis</i>) Bluegrass Using ISSR Markers

Fertile, advanced generation hybrids derived from crosses between Texas (Poa arachnifera Torr.) and Kentucky (Poa pratensis L.) bluegrass have been selected. The hybrids are currently being evaluated for low-input turf potential. Since they are derived from hand-harvested seed from first-generation hybrids located in field nurseries their exact genetic origin is unknown. This experiment was conducted to determine if there are still genetic relationships among the advanced generation hybrids and some of the Texas and Kentucky parents in their pedigrees. Four Inter Simple Sequence Repeat (ISSR) primer combinations resolved on 6% nondenaturing polyacrylamide gels resulted in 179 polymorphic bands that were scored to create a genetic similarity matrix and dendrogram based on Jaccard’s coefficient. The clustering of the advanced generation hybrids was generally in agreement with what would be expected based on their pedigrees and indicated it was more likely to select a fertile hybrid from an advanced generation, rather than the F1 generation.

Stable Transformation of Three Cultivars of Kentucky Bluegrass (Poa pratensis L.) by Particle Bombardment of Mature Seed-Derived Highly Regenerative Callus

High embryogenic calli of three cutivars of Kentucky bluegrass, Md, Bd, and Gm, were induced from mature embryos, and were proliferated on medium K3 and K5. Embryogenic calli were transformed with plamids pDM803 and pBY520 by microprojectile bombardment. Fourty-two transgenic lines had been obtained. The highest efficiency of transformation reached to 3.7% for cv. Md, 2.8% for cv. Gm, and 5 % for cv. Bd. The micro nutriment of Cupric had significant effect on transformation. The embryogenic callus cultured in dim-light condition had higher transformation efficiency than the green callus cultured in light condition for one month before transformation. The selective regime and selective pressure on the putative transgenic plants were important for obtaining the desire number of transgenic plants. It also affected the copy number of integrated genes in the genomic DNA of transgenic plants.

Analysis of drought resistance HVA1 gene under drought stress in different Poa pratensis cultivars

Total RNA from leaves of Poapratensis cultivars under drought stress was extracted for reversing transcription to cDNA and then cDNA as template for PCR reaction by designing primer of cds of Hordeum valgare HVA1 drought resistance gene from GenBank. The amplified products were positive recon identified by using procedures of recovery, connection, transformation and enzyme separation. The length of cloned gene sequence was 324 bp, identity reached 79.27% with Barley HVA1 gene that meaned the cloned gene sequence was the partial HVA1 gene of Poapratensis.

The Complete Chloroplast Genome of <i>Poa pratensis</i>(Poaceae), a High-Quality Forage

Poa pratensis L. (Poaceae) is a hardy, persistent, attractive forage and turf grass adapted to a wide range of soils and climate. In this study, we release and detail the complete chloroplast genome sequences of P. pratensis. The whole chloroplast genome was 135,649 bp in length and comprised 131 genes, including 85 protein-coding genes, 38 tRNA genes, 8 rRNA genes. The P. pratensis chloroplast genome had a GC content of 38.3%. The result of phylogenetic analysis showed that P. pratensis was closely related to P. pratensis cv. Qinghai and P. poophagorum. This study would provide useful genetic information for the protection of P. pratensis and other related species.

Callus induction and plant regeneration from mature bluegrass (Poa pratensis L.) seeds

A protocol was discussed for high efficient plant regeneration from seven bluegrass （Poa pratensis L.） cultivars via an in- direct callus induction and somatic embryogenesis method. Mature seeds were used as explants for callus initiation. Callus induction and proliferation efficiencies were investigated on NB, modified MS （MMS） and MS media, supplemented with 2.0 mg·L^-1 2,4-dichlorophenoxyacetic acid （2,4-D）. The MMS medium performed best. Based on the MMS medium, direct and indirect callus induction effects of bluegrass from mature seeds were compared at the range of 1-5 mg·L^-1 2,4-D contained in the medium. Under the direct callus induction method, the most suitable 2,4-D concentrations varied among cultivars. Under the indirect callus induction method, a significantly high callus induction frequency （93.33%-98.33%） was obtained and there were barely any statistically sig- nificant differences among the tested genetically diverse cultivars. Somatic embryos were promoted on the MMS medium supple- mented with 3 mg·L^-1 2,4-D, 0.1 mg·L^-1 kinetin and 0.8 mg·L^-1 CuSO4. Embryogenetic calli developed into plantlets on the MMS medium containing different concentrations of thidiazuron （TDZ）, and the differentiation frequencies varied in the range from 20.15% to 77.65%. The 0.25 mg·L^-1 TDZ was generally the most suitable concentration for the tested cultivars.

Effect of Spraying Liquid Mineral Mixed Fertilizers on the Mineral Elements of Potted Poa crymophila cv. Qinghai

Objective] The aim was to explain the accumulation characteristic of mineral elements in alpine grassland plants and the effect of supplementary supply on the nutrient changes of mineral elements. [Method] Potted Poa crymophila cv. Qinghai plants were regularly applied with liquid mineral mixed fertilizers, and samples were collected for analysis and detection. [Result] After the regular spraying of liquid mineral mixed fertilizers, the mineral elements in potted P. crymophila and its soil reduced （ P 〈0.05）, but the accumulation of corresponding mineral elements of P. crymophila in the control group was increased due to the ＂Starvation Effect＂, which was one of the endogenetic forces driving the increase in the accumulation of mineral elements. [Conclusion] This study is of great significance for the study of the accumulation of mineral elements in degraded grassland plants and its dynamic mechanism, as well as testing the hypothesis of the Starvation Effect of mineral elements. In addition, it also provides scientific bases and technical support for the restoration and remediation of degraded grassland and the development of ecological livestock husbandry.

硝酸钾配施有机肥对早熟禾生长及养分吸收的影响

早熟禾草坪在盐碱土壤上建植3~4年后会发生明显的退化,研究园林养护中采用硝酸钾配施有机肥的方式为其提供营养,对促进植株生长和提高坪用质量具有重要意义。试验设置在城市绿化带中,设置空白对照(K1)、硝酸钾化肥对照(K2)、化肥+发酵饼肥(K3)、化肥+腐殖酸复混肥(K4)4个处理,每个处理3次重复,研究了早熟禾生长和养分吸收变化。结果表明:K3与K1相比,在7~10月有利于提高早熟禾干物质积累量、含水量、叶绿素a、叶绿素b和类胡萝卜素含量,显著提高了植株氮、磷、钾吸收量;K3与K2相比,在8~9月显著提高了干物质积累量,7月和10月显著提高了叶绿素b和类胡萝卜素含量,8~10月提高了氮磷钾养分吸收量;K3与K4相比,在7~9月提高了干物质积累量,7~10月显著提高了叶绿素b和类胡萝卜素含量,促进了氮磷钾营养元素的吸收。综合分析认为,硝酸钾配施发酵饼肥为适宜施肥处理。

草地早熟禾苗期耐低温的生理特性研究

为了探究不同抗性草地早熟禾苗期对低温胁迫的生理特性差异,以10个常用草地早熟禾品种为试验材料,将幼苗叶片进行不同程度的低温胁迫处理,利用细胞伤害率和对应的低温度梯度进行Logistic方程拟合,获得半致死温度(LT50)并筛选抗寒品种和低温敏感品种,并以二者为试验材料进行相关生理指标的测定和相关性分析。结果表明,草地早熟禾‘普瑞芬’的LT_(50)为-17.5℃,表现出较好的抗寒性,‘帝国’的LT_(50)为-3.2℃,表现出对低温的敏感性;经低温胁迫处理后抗寒品种‘普瑞芬’的相对电导率和丙二醛含量显著下降并低于低温敏感品种‘帝国’,而‘普瑞芬’幼苗中干物质含量、相对含水量和苗长等生长指标和叶绿素含量、渗透调节物质(游离脯氨酸、可溶性糖和可溶性蛋白)和抗氧化酶活性(SOD、POD和CAT)均高于‘帝国’;经相关性分析表明,低温对草地早熟禾幼苗的干物质,苗长和根长及渗透调节物质含量影响较大且各指标之间相互作用。

硝酸钾配施发酵饼肥对景观草坪坪用质量的影响

通过研究硝酸钾配施发酵饼肥对草地早熟禾草坪坪用质量影响的规律,可以为城市园林草坪养护的科学施肥提供理论依据。试验在城市环境条件下,设置对照(CK)、硝酸钾(K_(1))、硝酸钾+发酵饼肥(K_(2))、硝酸钾+腐殖酸复混肥(K_(3))4个处理,小区试验设计,3次重复。结果表明:6月,K_(1)处理分蘖密度、株高、叶长、叶绿素含量均显著高于CK、K_(2)和K_(3)处理;7-10月,K_(2)分蘖密度显著高于CK、K_(1)和K_(3),6-8月K_(1)与K_(3)均显著高于CK;6-10月,K_(2)处理盖度显著高于CK,6-7月和9-10月K_(2)显著高于K_(1);7-10月K_(2)株高和叶长均显著高于CK,8月和10月K_(2)显著高于K_(1);7月、8月和10月,K_(2)处理叶宽显著高于对照;7-10月,K_(2)处理叶绿素含量和植株鲜重均显著高于CK,K_(2)显著高于K_(3)。综合分析认为,在现有施肥量基础上硝酸钾与发酵饼肥配合施用有利于显著提高草地早熟禾草坪坪用质量。

坡向对三江源区3种栽培植物生长及光合特征的影响

坡向作为主要地形因子,影响植物的生长和光合特征。本研究以果洛州达日县两种坡向(阴坡、阳坡)、3种栽培植物[青海草地早熟禾(Poa pratensis‘Qinghai’)、垂穗披碱草(Elymus nutans)和发草(Deschampsia cespitosa)]为对象,监测分析不同坡向不同植物的生长及光合特征,筛选出不同植物适宜的生境,为三江源区“黑土山”植被修复提供科学依据。结果显示:1)发草生长特性(株高、叶长、茎粗、叶面积和地上生物量)为阴坡显著高于阳坡(P<0.05),垂穗披碱草的比叶面积、地下生物量为阳坡显著高于阴坡(P<0.05),青海草地早熟禾的所有生长指标在坡向间无显著差异(P>0.05)。2)青海草地早熟禾的蒸腾速率(T_(r))、气孔导度(G_(s))为阳坡显著高于阴坡(P<0.05);垂穗披碱草的胞间CO_(2)浓度(C_(i))为阴坡显著高于阳坡(P<0.05);发草的C_(i)、G_(s)为阳坡显著高于阴坡(P<0.05)。研究结果表明,发草适宜在阴坡生长,阳坡生境利于青海草地早熟禾光合作用,垂穗披碱草在阳坡种植有利于其生长。

接种丛枝菌根真菌对不同生育期牧草生长的影响

为探究接种丛枝菌根真菌(Arbuscular mycorrhizal fungi,AMF)对不同生育期牧草生长的影响,本研究选取无芒雀麦(Bromus inermis)、冰草(Agropyron cristatum)、羊草(Leymus chinensis)和草地早熟禾(Poa pratensis)4种牧草进行盆栽试验,分别在苗期、拔节期和刈割后拔节期进行取样,测定植物生物量、菌根侵染率和菌丝密度等指标。结果表明:与不接种AMF相比,接种AMF显著提高了无芒雀麦和羊草的地上与地下生物量,但对刈割后拔节期冰草和草地早熟禾的地上和地下生物量无显著影响;4种牧草在不同生育期下菌根响应均为正效应,但是刈割后拔节期冰草、羊草和早熟禾菌根生长响应显著降低;4种牧草根系的菌根侵染率随生育期均呈增加趋势;刈割后拔节期土壤菌丝密度达到最高。因此,AMF与植物的共生关系具有物种特异性,共生作用随着生育期发生改变,随着生育期根内和根外AMF丰度增加,但菌根生长响应下降,说明AMF对植物幼苗有更强的促生作用,而这种促生作用与AMF丰度无关。

多胺调控青海草地早熟禾抗旱性

青海草地早熟禾(Poa pratensis L.cv.Qinghai)具有极强的耐寒性,已广泛应用于青海三江源退化高寒草地的修复,但对其抗旱性研究较少。本研究利用聚乙二醇(Polyethylene glycol,PEG)模拟干旱处理青海草地早熟禾,测定其响应干旱的生理变化,并检测外源腐胺、亚精胺处理提高青海草地早熟禾抗旱性的效应。结果显示,PEG处理后,青海草地早熟禾脯氨酸、腐胺、亚精胺和精胺含量不断升高,脯氨酸含量的变化与腐胺、亚精胺和精胺含量正相关;多胺合成关键酶基因ADC1,ADC2-1,SAMDC2,SPDS1基因的表达量也提高。外源腐胺与亚精胺预处理能够提高青海草地早熟禾抗旱性和脯氨酸含量,本文研究结果表明,多胺通过调控干旱条件下脯氨酸的积累提高青海草地早熟禾抗旱性。

草地早熟禾PpSWEET1b基因克隆及功能研究

SWEETs糖转运蛋白是一类在真核生物和原核生物中均存在的促进糖通过细胞膜流动的转运蛋白之一,参与调控植物的生长发育和胁迫响应过程。以草地早熟禾品种蓝月为材料,以叶片cDNA为模板克隆PpSWEET1b基因,采用花序侵染法转化拟南芥,获得了PpSWEET1b拟南芥过表达株系,并研究干旱和低温胁迫对转基因和野生型拟南芥生长、生理及基因表达的影响。结果表明:干旱和低温胁迫下,PpSWEET1b过表达植株生长状态均优于野生型,叶片MDA含量显著低于野生型,但葡萄糖含量较野生型显著增加,抗旱性和抗寒性明显增强;PpSWEET1b过表达植株可能协同SWEET2和SWEET3共同参与了对低温的响应。此外,以叶片DNA为模板克隆了PpSWEET1b基因的启动子序列,顺式作用元件预测发现,其含有多个与胁迫和激素响应、光响应相关的元件。综合以上结果表明,草地早熟禾PpSWEET1b基因在耐旱和耐寒方面发挥着重要作用,可为草坪草抵抗非生物胁迫生物育种提供新的优异基因资源。

磷添加对青海扁茎早熟禾各器官生物量及生态化学计量特征的影响

磷对植物体内氮代谢和氮效率均有促进作用,添加适量的磷肥有助于提高牧草产量和抗逆性。为探究不同磷添加下牧草不同器官生物量及元素浓度的变化规律,本研究设置7个磷添加梯度(0、30、60、90、120、150、180 kg/hm^(2)),分析了5龄青海扁茎早熟禾各器官(根、茎、叶)生物量的分配、生态化学计量特征及二者的相互关系。结果表明:(1)施磷量的增加能够显著影响青海扁茎早熟禾生物量,呈先增加后降低变化趋势:其中90 kg/hm^(2)施磷水平下地上和地下生物量最高,分别比对照增加73.99%、7.31%;(2)随施磷量增加,青海扁茎早熟禾各器官碳、氮、磷含量呈先增加后降低的变化趋势:其中150 kg/hm^(2)施磷水平下,根系氮和磷含量最高,较对照组增加37.05%和34.63%,而90 kg/hm^(2)水平下,叶片氮和磷含量最高,分别比对照增加11.60%和37.66%;(3)不同器官碳、氮、磷含量存在较大差异:其中,叶片碳、氮含量高于根系,而根系磷含量却高于叶片;(4)各器官生物量与碳、氮、磷含量呈显著正相关性(P<0.05),地上植株生物量(叶片、茎秆)与碳氮比、碳磷比呈极显著负相关性(P<0.01)。由此可见,磷添加能显著调控青海扁茎早熟禾营养元素吸收和平衡能力,适度磷添加(90 kg/hm^(2))对高效利用高龄青海扁茎早熟禾具有重要的生态和生产意义。

白三叶入侵对草地早熟禾功能性状及草坪质量的影响

【目的】白三叶入侵会挤占草坪草的生存空间,严重威胁草坪的质量和功能。明晰白三叶入侵对草坪植物草地早熟禾功能性状及草坪质量的影响,可深入了解白三叶入侵机制,为禾本科草坪的建植养护提供理论依据。【方法】以白三叶入侵草地早熟禾草坪为对象,采用样地调查方法考察不同白三叶入侵程度(对照及轻度、中度、重度入侵)下草地早熟禾功能性状及草坪质量的差异,并通过隶属函数法综合评价各入侵程度下草坪质量。【结果】(1)随白三叶入侵程度的增加,草地早熟禾各器官碳含量、叶片建成成本及碳氮比、碳磷比和氮磷比逐渐降低,而比叶面积、各器官氮和磷含量增大。(2)同一入侵程度下,草地早熟禾各器官碳、氮和磷含量均表现为叶大于根和茎,碳氮比和碳磷比表现为根和茎大于叶,而其氮磷比表现为茎和叶大于根。(3)随白三叶入侵程度的增加,草地早熟禾草坪密度、质地、绿度指数和均一性降低,而地上生物量和地下生物量增大。(4)隶属函数法综合评价结果显示,草坪质量以白三叶未入侵时最优,重度入侵时最差,且叶碳含量对草坪质量的影响最大。【结论】白三叶入侵改变了草地早熟禾功能性状,降低了入侵区草坪质量,严重影响了草坪景观和功能。

重金属Pb^(2+)对早熟禾种子萌发的影响

[目的]探究重金属铅对早熟禾种子萌发的影响。[方法]用不同浓度Pb^(2+)(20、40、60、80 mg/L)处理早熟禾种子,测定Pb2+对早熟禾种子萌发、叶绿素以及生根等指标的影响。[结果]随着Pb2+浓度的增加,草籽的萌发率、发芽指数降低,但降低趋势不明显。逐日萌发率在第3天出现高峰,早熟禾的根茎长度呈下降趋势。叶绿素a、叶绿素b含量降低明显,类胡萝卜素含量在Pb^(2+)浓度80 mg/L时增加。[结论]早熟禾种子的萌发率在Pb^(2+)浓度20~80 mg/L范围内受影响较小,而叶绿素含量、类胡萝卜素含量以及幼苗根茎的生长受到一定的抑制。

草地早熟禾派伦霉叶枯病病原菌的分离、致病性测定及鉴定

【目的】鉴定草地早熟禾(Poa pratensis)叶枯病。【方法】对草地早熟禾叶枯病症状进行描述,并利用形态学特征及分子生物学方法对病原进行鉴定。【结果】早熟禾叶枯病主要危害中上部叶片,常在叶尖和叶缘开始发病,逐渐向内扩展,形成较大枯死斑,病斑上形成大量小黑点。病原菌在PDA培养基上初呈白色,后变成橄榄绿和暗褐色,产生橘黄颗粒状液滴,背面有轮纹;菌丝有隔膜,无色或淡褐色;分生孢子多为长椭圆形,单胞无色,两端含油球,大小为4.2μm×1.8μm~7.7μm×4.8μm(平均值5.8μm×3.4μm);分生孢子器呈卵球形、长椭圆形或球形,大小为48.3μm×193.1μm~38.5μm×139.6μm(平均值106.0μm×86.4μm)。【结论】根据形态学特征和ITS基因序列分析,将病原鉴定为Peyronellaea glomerata,将该病害鉴定为早熟禾派伦霉叶枯病。该研究结果为早熟禾叶枯病的诊断和综合防治奠定了基础。

外源独脚金内酯对青海草地早熟禾根系生长的影响

独脚金内酯(SLs)是一种新型的植物激素,在调控植物的生长发育、刺激寄生性植物种子的萌发及介导植物在逆境胁迫中的适应性等方面具有重要的作用。为了明确独脚金内酯对植物根系生长的调控作用,文章以青海草地早熟禾为供试材料,用独脚金内酯类似物GR24代替独脚金内酯,采用随机区组试验设计,设置0 mol/L、0.1 mol/L、0.5 mol/L、1 mol/L 4个浓度梯度,6 d和12 d 2个处理周期,通过根系扫描仪对青海草地早熟禾根系生长状况进行研究。结果表明:(1)随着处理周期的延长,GR24显著提高了青海草地早熟禾的总根长、主根长、根表面积、根体积、根的平均直径和主根数,显著降低了其侧根长和侧根数,其中喷施12 d时,GR24对青海草地早熟禾根系有较好的促进作用。(2)同一周期,喷施0.1∼1 mol/L GR24对青海草地早熟禾根系的生长具有一定的促进作用,其中GR24的浓度为0.5 mol/L时,对其根部促生效果最好。该研究发现,施用0.5 mol/L的GR24溶液对青海草地早熟禾根部喷施12 d,对促进其根部生长具有良好的效果。