种子发芽生态研究

生活史策略是植物种群生态研究的重要领域,而种子发芽是植物生活史的重要阶段, 因此, 研究种子发芽规律及对策, 有助于认识和阐明物种进化及其生态适应特征。本论文以松嫩草原区植物为对象, 主要研究种子对恒温和变温的发芽响应, 比较变温梯度模拟的全球增温对C₃、C₄植物种子发芽的影响, 研究植物发芽模式及在不同温度条件下的变化, 探讨植物对盐、水势变化及盐与温度交互作用的发芽响应机制。     

Grass Seedling Demography and Sagebrush Steppe Restoration

Seeding is a key management tool for arid rangeland. In these systems, however, seeded species often fail to establish. A recent study in Wyoming big sagebrush steppe suggested that over 90% of seeded native grass individuals die before seedlings emerged. This current study examines the timing and rate of seed germination, seedling emergence, and seedling death related to this demographic bottleneck. We seeded monocultures of two native perennial bunchgrasses, Pseudoroegenaria spicata (Pursh) Á. Löve and Elymus elymoides (Raf.) Swezey, and one introduced bunchgrass, Agropyron desertorum (Fisch. ex Link) Schult., in 2007, 2008, and 2009 and tracked sown seed and seedling fate. Across the study years and species we found that germination was rapid and high, with species obtaining 50% germination by December, less than 2 mo after planting. Emergence of germinated seed did not occur until late February for A. desertorum and March for the two native grasses. In 2007 the majority of emergence and death was constrained to several weeks, whereas in 2008 and 2009 emergence and death was distributed across several months. The timing of seedling emergence did not influence survival probability or midday plant water potential (probability of exceedance &spilt; 0.05). Survival probabilities once seedlings emerged were greater for native species (0.71) than A. desertorum (0.51) in 2 of the 3 study yr (probability of exceedance &spigt; 0.98). The early germination of grasses following fall seeding, and the long 2- to 3-mo period that germinated grass seed remain in the soil before emerging, support the hypothesis that seedling recruitment might be limited largely by ecological processes and conditions during winter or early spring (such as soil freeze–thaw events, seed pathogens, or physical crusts). Delaying seeding to early winter or spring and other management tools that mitigate these factors driving this bottleneck might greatly improve restoration outcomes in these systems.     

应用植物抗盐剂提高桑树种子出苗期耐盐力试验

将植物抗盐剂首次应用于桑树实生育苗,并取得较好效果,经抗盐剂浸泡的桑种子的耐盐力约为未处理桑种子的两倍。     

生物种衣剂包衣对桑种子萌发和幼苗生长的影响

将不同质量浓度的黄腐酸(50、200、600 mg/L FA)+高吸水树脂+多菌灵以及不同质量浓度的赤霉素(25、50、100 mg/L GA3)+高吸水树脂+多菌灵制作成6种生物种衣剂,对隔年桑种子进行包衣处理。包衣后的桑种子发芽率以及脂肪酸含量、α-淀粉酶活力、幼苗根系活力、可溶性蛋白含量以及出苗率、幼苗根长及幼苗鲜质量均比对照提高,其中赤霉素种衣剂2号(含50 mg/L赤霉素)和黄腐酸种衣剂2号(含200 mg/L黄腐酸)的效果最好:分别使桑种子发芽率提高21%、16%;分别使桑种子萌发时的脂肪酸含量提高79%、63%,α-淀粉酶活力提高34%、30%,根系活力提高82%、55%,可溶性蛋白含量提高5%、12%;分别使出苗率提高27%、29%,幼苗根长提高5%、7%,幼苗鲜质量提高22%、19%。依据试验结果认为,采用生物种衣剂对桑种子进行包衣处理,对桑种子的萌发及幼苗的生长均有一定的促进作用。     

草地早熟禾种子萌发和幼苗生长对铅胁迫的适应性

为研究草地早熟禾（Poa pratensis）对铅（Pb）的适应性,本研究采用盆栽试验分析了铅胁迫（Pb²⁺浓度为0,100,200,300,400,500,600 mg·L^-1）下草地早熟禾种子的萌发情况和幼苗生理生化的变化,结果显示：萌发期,随着Pb²⁺浓度的增加,发芽率和芽苗的芽长先升高后降低;发芽势、发芽指数、活力指数、芽苗的根长和苗重均随着Pb²⁺浓度的增加而逐渐降低;幼苗期,叶绿素含量在Pb²⁺浓度小于200 mg·L^-1时无明显变化,在Pb²⁺浓度大于400 mg·L^-1时显著低于对照;细胞膜相对透性、丙二醛（Malondialdehyde,MDA）和脯氨酸（Proline,Pro）含量均随着Pb²⁺浓度的增加而升高,保护酶活性和活性氧自由基均随着Pb²⁺浓度增加先升高后降低。试验结果表明浓度小于200 mg·L^-1的铅胁迫可促进草地早熟禾种子的发芽,大于300 mg·L^-1则显著抑制;苗期在Pb²⁺浓度小于400 mg·L^-1时草地早熟禾可通过激活自身的抗氧化酶系统和增加Pro含量抑制细胞膜相对透性、MDA和活性氧自由基的增加以适应Pb²⁺胁迫,大于400 mg·L^-1时则影响其正常生长,可见土壤中铅浓度小于300 mg·L^-1的铅污染地区可种植草地早熟禾绿化环境。     

Weather Tools for Retrospective Assessment of Restoration Outcomes

Rangeland seeding practices in the Intermountain western United States are predominantly implemented in the year immediately following wildfire for the purposes of Emergency Stabilization and Rehabilitation (ESR). This necessarily links restoration and rehabilitation outcomes to the probability of a single year providing sufficiently favorable microclimatic conditions for desirable plant establishment. Field research studies in rangeland restoration are also typically of limited duration, and published results may not represent the full spectrum of conditions likely to be experienced at a given site. We propose that location-specific and temporal weather analysis may enhance the interpretation of historical planting data, support expanded inferences from short-term field studies, and facilitate meta-analysis of diverse field studies in rangeland restoration. We describe access and use of new databases and tools that can be used to characterize and rank weather and soil-microclimatic variables and suggest some standard graphs and weather metrics to establish a longer-term perspective for the interpretation of rangeland restoration outcomes. Tools of this type may also be useful in the interpretation of a wide range of agricultural and natural resource applications that are driven by similar weather inputs, particularly in arid and semiarid systems that exhibit high annual and seasonal variability in precipitation and temperature.     

柳枝稷种子活力及幼苗生长对人工老化处理的响应

为研究柳枝稷(Panicum virgatum L.)种子活力及幼苗生长对人工老化处理的响应,分别对供试柳枝稷种子进行高温高湿老化(AA)、饱和盐溶液老化(SSAA)以及催腐劣变(CD)处理,测定不同老化处理后柳枝稷种子萌发、种子浸出液电导率、吸水率及幼苗生长等种子活力相关的部分指标,并对部分指标做了,Pearson相关性分析,以探究各指标间的关联,从而探讨柳枝稷种子的老化特性。结果表明:随着老化时间的延长,不同老化方式种子的发芽势、发芽率、发芽指数、活力指数以及活力等指标均呈现下降趋势,而浸出液电导率和幼苗生物量呈增大趋势。由此可知,老化处理降低了柳枝稷种子活力,并破坏了种子细胞膜结构的完整性,且随着处理时间延长,膜透性逐渐加剧,3种人工老化方法对柳枝稷种子的老化作用由强到弱依次是:催腐劣变老化法(CD)高温高湿老化法(AA)饱和盐溶液老化法(SSAA)。     

天仙子种子浸提液对黑麦草种子萌发和幼苗生长的化感作用

为了探究天仙子(Hyoscyamnus niger L.)对禾本科牧草的化感作用,以天仙子和黑麦草(Lolium perenne L.)为材料,通过5个不同浓度天仙子种子浸提液(0,0.025,0.05,0.075,0.1 g·mL-1),对黑麦草种子萌发和幼苗生长进行处理,测定黑麦草种子萌发和幼苗生长情况.结果表明:...     

盐胁迫对柳枝稷种子萌发和幼苗生长的影响

选用NaCl混合盐和Na₂SO₄混合盐2类盐溶液处理柳枝稷(Panicumvirgatum)种子,研究盐胁迫对柳枝稷种子萌发和幼苗生长的影响,以期为柳枝稷耐盐性研究提供科学依据。NaCl混合盐和Na₂SO₄混合盐浓度均分别设0(CK),0.4%,0.8%,1.2%,1.6%,2.0%。结果表明:种子发芽率随着盐浓度的增加逐渐降低,在萌发初期,各浓度的盐溶液都具有抑制作用,随着发芽天数延长,低浓度盐溶液(Na₂SO₄混合盐0.4%,0.8%和1.2%,NaCl混合盐0.4%)抑制作用缓解,处理11 d后,柳枝稷种子的发芽率与对照相比没有显著性差异,表明柳枝稷具有一定的耐盐性。0.4%的Na₂SO₄混合盐和NaCl混合盐处理的柳枝稷种子的发芽率和发芽指数均显著高于对照,有促进柳枝稷发芽的作用。同时,相同盐浓度处理下,NaCl混合盐溶液处理的发芽率和幼苗活力指数、相对幼苗活力指数低于Na₂SO₄混合盐,NaCl混合盐溶液对柳枝稷种子萌发的胁迫高于Na₂SO₄混合液。     

三种针茅种子萌发特性及幼苗生长的研究

研究三种针茅种子的萌发特性及其幼苗生长。发现三种针茅种子的最适萌发温度有一定差异性；通过测定种子活力了解到大部分的种子处于休眠状态；成苗后的针茅地上地下生长规律基本符合Logistic曲线。     

黑沙蒿对自身种子萌发与幼苗生长的化感作用研究

采用生物测定方法研究了黑沙蒿（Artemisia ordosica）枝叶与枯落物超声波浸提液对自身种子萌发与幼苗生长的化感作用,并分级计算敏感指数以综合评价其化感效应。结果表明：黑沙蒿枝叶浸提液可抑制自身种子萌发与幼苗生长,抑制作用在种子萌发期较为强烈,其中种子发芽指数受抑制程度明显大于发芽率;在幼苗生长期,对相对电导率、丙二醛含量、苗高和根干重抑制较为明显;2个生长期内抑制作用均随浓度的升高明显加强。黑沙蒿枯落物浸提液对自身种子萌发有轻微抑制作用,而对幼苗生长表现为促进作用,且随浓度的升高而加强,根干重、根长和苗干重是敏感性较强的指标。黑沙蒿枝叶浸提液可延缓自身种子萌发,减少萌发数目,损伤幼苗细胞膜系统;枯落物浸提液则可促进幼苗根系生长,增加干物质累积。     

超干处理对柳枝稷种子活力及幼苗生长特性的影响

研究超干处理对柳枝稷(Panicum virgatum L.)种子活力及幼苗生长特性的影响,为柳枝稷种子耐干性及贮藏提供理论基础。采用硅胶干燥法将柳枝稷种子含水量由9%分别降至7%,5%,3%,2%,1%,测定不同含水量条件下种子的活力以及种子萌发后第14 d幼苗的叶面积、根长、苗长、根冠比、鲜重、干重及相对电导率等指标的影响。柳枝稷种子含水量由对照9%降到2%的过程中,种子仍保持较高活力。含水量降至1%种子活力显著下降,但种子的相对电导率与种子活力没有显著相关性。超干处理后幼苗生长正常。柳枝稷种子属于正常型种子,其贮藏的安全水分下限为2%。超干处理并没有破坏柳枝稷种子细胞膜的完整性,也未对幼苗的生长造成损伤。     

混合盐碱胁迫对5种禾草种子萌发及幼苗生长的影响

以农菁11号羊草(Leymus chinensis‘ Nongjing 11’)、农菁7号偃麦草(Elytrigria repens‘ Nongjing 7’)等5个禾本科牧草品种为试验材料,研究不同浓度(0,20,40,60,80,100,120 mmol·L-1)混合盐碱(NaCl,Na2SO4,NaHCO3和Na2CO3)胁迫对种子萌发及幼苗生长的影响,为牧草品种在盐碱化草地的建植提供参考.结果表明:低浓度胁迫(≤20 mmol· L-1)可提高农菁11号羊草、东北羊草和农菁7号偃麦草种子的萌发能力,高浓度(＞60mmol·L-1)降低种子萌发.农菁7号偃麦草各处理间的发芽率差异不明显(     

卡那霉素对阿尔冈金种子萌发及幼苗生长的影响

通过室内发芽试验,研究不同浓度卡那霉素溶液对紫花苜蓿品种阿尔冈金种子发芽和幼苗生长的影响,结果表明:0~100mg/L浓度卡那霉素对种子发芽势和幼苗主根粗没有显著影响,但明显影响种子发芽率和幼苗的株高、真叶数、主根长、侧根数和鲜重。低浓度(10mg/L)的卡那霉素即可显著抑制幼苗株高、真叶数、主根长、侧根数和鲜重,浓度为50mg/L时有白化苗的出现,由此可确定50mg/L为阿尔冈金的卡那霉素耐性临界浓度。     

我国中药材种子种苗标准发布状况及分析

为全面掌握我国中药材种子种苗标准的研究现状,采用文献研究法,对目前我国中药材种子种苗标准,从标准编制和发布机构、标准的类型、年度分布、单位分布、标准涉及的药材品种等方面进行了检索分析,研究认为,我国中药材种子种苗的标准数量明显不足、多年来增幅不大、同类标准名称不尽一致,标准研制地区差异显著。研究建议多团体协同合作,加快我国中药材种子种苗标准的研制,将标准精确定位于具体品种和产区,尽快完善我国中药材种子种苗质量专业检测机构,促进我国中药材种子种苗产业的健康可持续发展。     

驼绒藜属牧草种苗耐盐性评价及生理基础研究

对7份驼绒藜属材料种子萌发及幼苗进行耐盐性研究。结果表明,种苗具有较高的耐盐性,在种间及种内生态型间存在差异,其中华北驼绒藜耐盐性最强,其次为华北驼绒藜科尔沁生态型,驼绒藜荒漠生态型和心叶驼绒藜耐盐性最弱。种苗的耐盐能力和种子的活力呈正相关,在恶劣生境条件下形成的种子活力较低,种苗的耐盐力也较低;种苗耐盐半致死浓度与种子活力3项指标呈显著或极显著正相关(r=0.82^*、0.93^**、0.90^**)。而盐性生理基础的研究结果表明,种子耐盐性的指标与种子含氮量呈极显著正相关(r=0.88^**、0.90^**),与种子含磷量呈正相关(r=0.77、0.68),与含糖量相关性较小(r=-0.33～0.55)。初步认为种子耐盐半致死浓度、种子活力指数和含氮量可以作为种子耐盐性评价和选育的生理指标。     

镉和pH对柳枝稷种子萌发及幼苗的耦合作用研究

植物修复技术是一种清除土壤中重金属有效、经济的生态技术。为在重金属污染的土壤环境下建植柳枝稷进行植物修复提供基础理论依据,本试验采用三因素五水平正交旋转试验设计,研究镉、pH和浸种及其耦合作用分别对高地型Blackwell(B品种)和低地型Kanlow(K品种)柳枝稷种子萌发及幼苗发育的影响。结果表明,不同镉处理下两个品种柳枝稷种子发芽率与对照差异均不显著,但是浸种可显著提高柳枝稷种子发芽指数和种子活力指数。随着镉浓度的增加,其幼苗根长、苗长、及种子活力均呈缓慢下降趋势,且镉对幼根生长的影响大于其对幼苗生长的影响。B品种比K品种更加耐受镉胁迫;播种前浸种可以缓解镉胁迫,促进柳枝稷幼苗和根的发育。镉和pH对柳枝稷种子萌发和幼苗发育存在耦合作用,同时pH为4.8时柳枝稷幼苗根长苗长及种子活力有最大值。在较低浓度的镉胁迫环境下(150μmol/L),高地型B品种比低地型K品种种子萌发和幼苗生长综合表现更好,同时适当浸种和偏酸性条件均有利于柳枝稷幼苗在镉污染土壤环境中的生长。本试验表明柳枝稷对镉胁迫有较强的耐受性,具有一定修复镉污染土壤的潜能,在实际应用中可通过推广种植柳枝稷来改善镉污染的土壤环境。     

Postfire Restoration of Soil Hydrology and Wildland Vegetation Using Surfactant Seed Coating Technology

In semiarid environments, soil water repellency can contribute to reseeding failure by reducing soil moisture availability. Nonionic soil surfactants (wetting agents) have been shown to be effective in enhancing infiltration and improving root-zone water reserves in water-repellent soils. However, the application of soil surfactants in wildland ecosystems can be logistically and economically prohibitive. In this study, we evaluated a potential solution for applying soil surfactants using seed coating technology. Through this technology, the seed is used as a carrier for the soil surfactant. After planting, water transfers the surfactant from the seed into the soil where it ameliorates the water repellency within the seed's microsite. The objectives of this research were 1) to establish the efficacy of a surfactant seed coating (SSC) in ameliorating soil water repellency, and 2) to determine the influence of SSC on seedling emergence and plant survival. To accomplish the first objective, detailed soil column experiments were conducted in the laboratory on water-repellent soil obtained from a burned pinyon-juniper (Pinus-Juniperus spp.) woodland. The second objective was met through greenhouse testing of SSC applied to crested wheatgrass and bluebunch wheatgrass seed, using the same soil as used in the first objective. Results indicate that SSC increased soil water infiltration, percolation, and retention. This technology had no influence on seedling emergence for crested wheatgrass, but SSC improved bluebunch wheatgrass (Pseudoroegneria spicata [Pursh] Á. Löve) emergence threefold. Plant survival was dramatically improved by the SSC. Only 0.75% of the seedlings that grew from noncoated seed survived to the end of the study, whereas 37% of the plants survived in the SSC treatment. Overall, these results indicate that it may be plausible for SSC to improve postfire restoration efforts by restoring soil hydrologic function and increasing seedling emergence and early seedling development.     

大狼毒对紫花苜蓿种子萌发及幼苗生长的化感效应研究

为探究大狼毒(Euphorbia jolkinii)是否会对其它物种产生化感作用,促进大狼毒蔓延区退化草地的恢复治理,本研究以紫花苜蓿(Medicago sativa)为受体材料,采用培养皿滤纸法和穴盘培养法,开展大狼毒对紫花苜蓿种子萌发及幼苗生长的化感效应研究,结果表明：大狼毒对紫花苜蓿种子萌发率和萌发进程体现为“化感抑制作用”,且抑制作用随浸提液浓度的增加而增强。大狼毒茎叶、根粉碎物在腐解过程中,会导致紫花苜蓿根系活力和可溶性糖含量降低,丙二醛(Malondialdehyde, MDA)含量升高,进而显著抑制紫花苜蓿幼苗的生长(P<0.05),且抑制作用随用量的增加而增强。大狼毒根部土壤对紫花苜蓿幼苗生长无显著影响。大狼毒根部土壤、根、茎叶对紫花苜蓿萌发生长的综合化感效应强弱顺序为：根>茎叶>根部土壤。