白三叶(Trifolium repens)入侵对城市草坪生态系统土壤动物的影响

土壤动物是土壤生态系统中十分活跃的生物类群之一,也是城市草坪生态系统的重要组成部分。由于外来植物白三叶入侵,草坪土壤动物可能受到直接或间接的影响,进而改变城市草坪生态系统功能及过程。研究白三叶入侵对城市草坪生态系统土壤动物的影响,可为进一步了解外来植物入侵机制及城市草坪的建植养护提供理论依据。采用野外调查的试验方法对4种不同入侵程度下城市草坪的土壤动物群落特征和土壤理化性质进行了研究。结果如下:4种不同入侵程度的草坪样地共捕获土壤动物30099只,隶属于19目43科,其中小杆科、线蚓科和跳虫科为优势类群;土壤动物个体数量和类群数量整体表现为中度入侵>轻度入侵>对照>重度入侵,符合中度干扰假说;土壤动物个体数量和类群数量的季节动态主要表现为夏秋较高,冬春较低。CCA分析显示,土壤理化因子中铵态N对土壤动物影响相对较小,可能与白三叶改善了草坪土壤的供N水平并使其不成为土壤动物分布的限制因子有关;同时,土壤理化因子对土壤动物优势类群影响较小,而主要影响常见和稀有类群。总体而言,一定程度的白三叶入侵增加了土壤动物群落的多样性,但当达到重度入侵时,白三叶形成单优群落,减少了植物多样性,进而使土壤动物可获得的生活资源减少,土壤动物群落多样性呈下降趋势;白三叶入侵后通过改变土壤理化性质,影响到土壤动物常见和稀有类群,并最终改变草坪土壤动物的群落结构。

Effects of Phosphate and Lime Application on Growth of Trifolium repens,Chamaecrista rotundifolia and Macroptilium atropurpureum in Red Soils

[Objective] The aim was to research effects of P fertilizer and lime on growth of Trrifolium repens, Chamaecrista rotundifolia and Macroptilium atropur- pureum, to provide references for cultivation of the three plants. [Method] Pot experiments were conducted with Trrifolium repens, Charnaecrista rotundifolia and Macroptilium atropurpureum in 2010 in order to research effects of lime and P fer-tilizer mixture on growth of the plants in southern hilly acidic red soils. [Result] With lime amount fixed, application of P fertilizer would enhance plant height, total tiller number and dry matter. When P fertilizer was not applied, however, plant height of the three plants achieved the peak by lime at 1.4 g/kg which proved best for improvement of acidity of red soils. With P fertilizer at 200 mg/kg was applied, biomass of Trifolium repens and Macroptilium atropurpureum achieved the highest by lime at 2.1 g/kg, but total biomass of Chamaecrista rotundifolia was the highest by lime at 1.4 g/kg. [Conclusion] The research provides references for planting and production of Trifolium repens, Chamaecrista rotundifolia and Macroptilium atropur-pureum in southern hilly regions.

土壤水分梯度对白三叶(Trifolium repens)光合作用和根系分布的影响

通过对两个品种白三叶Trifolium repenscv.Haifa（海发）和Trifolium repenscv.Rivendel（瑞文德）盆栽试验,模拟3种不同的土壤水分状况（无水分胁迫：保持植株良好的水分供应;轻度胁迫：表层0-20 cm土壤处于干旱状态;重度胁迫：表层0-20 cm土壤处于极干旱状态,20-40 cm土壤处于干旱状态）对白三叶光合作用和根系生长的影响。结果表明,当植株未遭受水分胁迫时,两个品种白三叶的光合作用和根系生长状况没有明显差异;当表层0-20 cm处于干旱状态时,‘海发’在处理后期的净光合速率和水分利用效率升高,根系生长量增大,表现出促进作用,‘瑞文德’受到的影响不显著;当表层0-20 cm处于极干旱、20-40cm处于干旱状态时,‘海发’在处理前期受到轻微影响,随后恢复正常状态,‘瑞文德’则受到较严重的影响。随着干旱程度的加深和时间的延长,白三叶的根冠比逐渐增大。与‘瑞文德’相比,在相同时期相同胁迫程度下,‘海发’的根冠比没有显著差异,但深根数量大大超过‘瑞文德’,因而,‘海发’的耐旱能力强于‘瑞文德’。

白三叶(Trifolium repens L)无性系植物分株间的生理整合作用

研究了白三叶无性系植物种群，在相互连接的分株之间生理上相互依存的程度。结果显示子代在生理上取决于母株资源的转移，这一依赖性随时间而下降。相互连接的分株，一部分被遮荫至１０％，而照光分株光合速率明显增加。光被限制期间，分株将重新整合，遮荫分株无性系中由其它分株提供同化物。在子代匍匐茎数目和长度上有一个权衡。当资源受限制时，产生极少较长的子代匍匐茎，结果提高了子代能够占据更有利条件的可能性。在分株之间，生理整合作用降低了子代建立所面临的危险，使同源分株在资源的可利用能力上整合到一个局部的异质环境，增加同源分株间的竞争能力，缓冲所面对的局部微生境的选择。

白车轴草(Trifolium repens)植株抗病性和生长与植物病史的关系(英文)

从白车轴草 (Trifoliumrepens)自然种群中采集无白车轴草单孢锈菌病史的无性系 (clones) 17个 ,有白车轴草单孢锈菌病史的无性系 14个 ,分别作为抗病型和感受型植物实验材料 ;采集白车轴草单孢锈菌 (Uromycestrifolii repentis)菌系 (strains) 10个 ,作为病菌实验材料 .分别设置并进行了两个温室实验、一个田间盆栽实验和一个原生长地移栽实验 ,实验处理上分对照、单菌系接种和 10个菌系接种等 3种 .实验结果表明 ,无论是用单菌系接种还是 10个菌系接种 ,植株发病的概率和程度均与其抗病性有关 ,抗病型植株 (无病史 )发病的概率和程度显著低于感受型 (有病史 )植株 .在相同处理的实验中 (无论是田间实验还是温室实验 ) ,无病史植株和有病史植株的生长无显著差异 ;不同处理田间实验植株的生长有显著差异 ,病情愈重 ,生长愈差 .无病史植株的抗病性明显强于有病史植株 .但是 ,原生长地的移栽实验结果表明 ,在无病原菌存在的情况下 ,有病史植株的 (叶 )生长显著好于无病史植株 .可以认为 ,研究生物个体对环境因子反应性差异的实验应当在自然条件下和自然梯度范围内进行 .

Response of Chlorophyll Fluorescence Characteristic of Trifolium repens L. to Water Stress

[Objective] The aim was to study response of chlorophyll fluorescence parameters in Trifolium repens L.leaves to water stress from perspective of physiology.[Method] With T.repens cultivar ＂Haifa＂ as tested material,three soil water content levels were set to culture plants,including 75% （no stress,CK）,50% （moderate stress,LD） and 25% （severe stress,HD）,the effects of water stress on chlorophyll fluorescence parameters were determined.[Result] The results showed that the chlorophyll fluorescence parameters changed a little when the relative soil moisture content was 75% and 50%,while the chlorophyll fluorescence parameters such as conversion efficiency of primary light energy （Fv/Fm） of PS Ⅱ,the photochemical quenching coefficient （qP） and the quantum yield of PS Ⅱ electron transport （φPS Ⅱ） decreased respectively when the relative soil moisture content was 25%.[Conclusion] When T.repens in severe drought conditions,the physiological functions were damaged,showing symptoms of drought injury.

基于SSR分子标记的13个白三叶(Trifolium repens L.)品种指纹图谱构建

白三叶(Trifolium repens L.)是一种多年生冷季型豆科牧草,因其具有产量高、品质优良等特点,已成为我国西南地区重要的优质牧草。为分析国外引进的白三叶新品种的遗传多样性,本研究利用简单重复序列(Simple sequence repeats,SSR)分子标记对13个白三叶品种进行品种鉴定及DNA指纹图谱的构建,以期利用此方法直接、有效的鉴定和区分白三叶品种。结果表明:20对SSR引物共扩增出115条不同的条带,其中多态性条带104条(90.4%);同时所有引物的多态信息含量(Polymorphism information content,PIC)范围为0.198~0.455,平均值为0.333;AMOVA分析表明,49%的遗传变异发生在品种间,51%发生在品种内部;聚类分析和主成分分析的结果表明,13个品种的亲缘关系中,‘超级海法’和‘海法’的亲缘关系最密切,‘米莉格’和‘克朗德’的遗传距离较远;利用6种具有代表性的引物gtrs1164,gtrs573,gtrs541,gtrs171,gtrs536和gtrs173构建的DNA指纹图谱具有较强的识别能力,可将13个白三叶品种有效的鉴定区别开来。综上所述,本试验所选用的6对引物具有良好的多态性,可用于白三叶品种的指纹图谱构建。

适生植物白三叶草(Trifolium repens)对陇东地区不同浓度油污土壤场地生态修复的响应

为了明确白三叶草(Trifolium repens)生物量和土壤环境指标对不同浓度油污土壤场地生态修复的响应方式,采用常规方法测定了不同油污浓度胁迫下其根际土壤总石油烃(TPH)降解率、生物量指标、根际微生物数量和酶活性的变化情况。结果显示:(1)随着油污浓度增加,根际TPH降解率依次为75. 49±2. 14%、75. 57±2. 52%,55. 02±2. 06%、33. 14±2. 22%和13. 34±1. 53%;(2) 70000mg/kg-1时其出芽时间延迟至15. 61±1. 65d,而出芽率、植物体干重和株高则分别下降了38. 11%、40. 44%和51. 18%;(3)当油污浓度≤50000mg/kg时土壤脱氢酶、多酚氧化酶以及土壤烷烃和芳烃降解菌数量均与油污浓度均呈正相关关系(P <0. 01),但在70000mg/kg时均受到显著抑制(P <0. 05);(4) 50000和70000mg/kg时植物生物量指标完全受到抑制,其根际土壤微生物特性和土壤酶活性高低是决定重度污染TPH降解的主要环境因素。

三叶草(Trifolium repens)用于土壤镉污染的修复潜力

通过温室盆栽试验法,研究了土壤镉(Cd)污染下三叶草对土壤Cd的富集特征及土壤Cd的净化能力等,以期为三叶草对土壤Cd的生态修复提供依据。结果表明:三叶草具有较好的Cd耐受性,总生物量增加值介于2.0~3.7 g。随着土壤Cd处理浓度增加,三叶草根、茎、叶中Cd含量分别高达178.6、101.3、130.9 mg·kg-1,富集系数(BF)分别介于9.7~17.9、3.0~10.1、3.1~13.1,富集能力大小总体表现为根>叶>茎,转运系数(TF)值均≥1(除T2处理),表明三叶草有较强的Cd富集能力,且能较好地将Cd转运至地上部位;三叶草根、茎、叶对Cd的吸收量均随着土壤Cd处理浓度的升高而递增,地上部位(茎、叶)吸Cd百分率(占总吸Cd量)最高达87.2%,对土壤Cd净化率最高达6.2%。因此得出三叶草具有作为Cd超积累植物的较好潜力,可以进行污染区域美化改造和Cd污染修复。

Selection,Identification and Growth Promotion of Inorganic Phosphorus-dissolving Bacterial Strains in Rhizosphere of Trifolium repens

[Objective] The aim was to select and identify inorganic phosphorus-dissolving bacteria in rhizosphere of Trifolium repens,and to research related effects of growth promotion.[Method] Phosphate solubilizing bacteria in rhizosphere of Trifolium repens in Guizhou Province were separated and selected to determine its ability of phosphate solubilizing and IAA secretion,and growth promotion effect.[Result] Phosphate solubilizing bacteria were multiple and varied in rhizosphere of Trifolium repens;solubilizing quantities of phosphorus from calcium phosphate by RW2,RW6 and RW18 were 337.39,447.45 and 462.03 μg/ml;solubilizing quantity was none of linear relation with organic acid;RW2 proved the one secreted most IAA at 12.69 μg/ml,followed by RW18 at 12.34 μg/ml;the three strains were all of Leclercia sp.,but were of none pathogenicity for seedlings of Trifolium repens,instead,a kind of growth promotion was found.Detailedly,RW18 was most effective in growth promotion for Trifolium repens and plant height,root length and weight,and aboveground biomass increased by 110.98%,9.17%,46.17% and 2% respectively.Hence,RW18 is of great potential.[Conclusion] The research provides scientific references for developing phosphate solubilizing bacteria and compound inoculation and develops a novel way to relieve barren soils,save phosphorus resource,reduce environment pollution,and guarantee sustainable development of agriculture and animal husbandry.

Construction of Clonal Growth Models in Trifolium repens

The suitability of models for describing the clonal growth of Trifolium repens population was discussed. The results showed that deterministic models were inadequate for describing its clonal growth, but the diffusion models and the randomwalk models suited for the clonal growth characteristics of the population. And it was found that random-walk models were better than diffusion models for describing a population in an environment with rich natural resources, and the latter was better in a poor environment.

Changes in Florets’Vertical Direction within Inflorescence Affects Pollinator Behavior,and Fitness in Trifolium repens

interactions,many flowers are known to display their attractive qualities,such as scent emission,flower rewards and floral vertical direction,in a rhythmic fashion.However,less is known about how plants regulate the relationship between these flower traits to adapt to pollinator visiting behavior and increase reproduction success.Here we investigated the adaptive significance of the flower bending from erect to downward in Trifolium repens.We observed the flowering dynamic characteristics(changes of vertical direction of florets,flowering number,pollen grain numbers,pollen viability and stigma receptivity over time after blossom)and the factors affecting the rate of flower bending in T.repens.Then we altered the vertical direction of florets in inflorescence of different types(upright and downward),and compared the pollinator behaviors and female reproductive success.Our results showed that florets opened sequentially in inflorescence,and then bend downwards slowly after flowering.The bending speed of florets was mainly influenced by pollination,and bending angle increased with the prolongation of flowering time,while the pollen germination rate,stigma receptivity and nectar secretion has a rhythm of“lowhigh-low”during the whole period with the time going.The visiting frequency of all the four species of pollinators on upward flowers was significantly higher than that of downward flowers,and they especially prefer to visit flowers with a bending angle of 30°–60°,when the flowers was exactly of the highest flower rewards(nectar secretion and number of pollen grains),stigma receptivity and pollen germination rate.The seed set ratio and fruit set ratio of upward flowers were significantly higher than downward flowers,but significantly lower than unmanipulated flowers.Our results indicated that the T.repens could increase female and male fitness by accurate pollination.The most suitable flower angle saves pollinators’visiting energy and enables them to obtain the highest nectar rewards.This coordination between plants and pollinators maximizes the interests of them,which is a crucial factor in initiating specialized plant-pollinator relationships.

Resource Sharing by the Different Clonal White Clover Plant(Trifolium repens L.)

Resource sharing in the different parts of the clonal white clover plant (Trifolium repens L.) was investigated in this study. The results showed that the integration of water and nitrogen metabolism occured among parental, young and old branches of a plant when water passed through its stolons. Under the sufficient supply of light, water and nutrients from soil the newly developed branches showed similar capacity in taking in sufficient water and nitrogen to that of old branches. The development of the new branches did not affect the growth of the old and parental branches attached. The results also indicated that energy values in roots was significantly related with plant age, however, the energy values were various in the different parts of a plant.

三叶草根浸提液对3种牧草种子萌发及幼苗生长的影响

为探索三叶草的防控及利用提供理论依据,采用培养皿生物测定法分析,研究不同浓度(0、2.5、5.0、10.0 g·L-1)三叶草根浸提液对黑麦草(Lolium perenne)、高羊茅(Festuca arundinac)和赖草(Leymus secalinus)种子萌发及幼苗生长的化感作用,以及三叶草(Trifolium repens)的生长竞争力和成功入侵原因。结果表明,三叶草根浸提液对3种牧草种子萌发(发芽率、发芽指数)和幼苗生长(根长、苗长、根干重、苗干重)均有化感作用,且其化感作用效应存在一定的差异。三叶草根浸提液对黑麦草种子萌发具有抑制作用,对高羊茅和赖草的种子萌发有“低促高抑”作用,对黑麦草根长和干重、苗高和干重均具有抑制作用,对高羊茅和赖草则表现为低浓度的促进、高浓度的抑制效应。从综合化感效应指数来看,随着三叶草根浸提液浓度的增加,对黑麦草具有抑制作用,而对高羊茅和赖草有“低促高抑”的双重作用。3种供试牧草对三叶草根浸提液的敏感程度也有差异,表现为:黑麦草>高羊茅>赖草。入侵植物三叶草根浸提液对3种牧草的化感效应较为明显,在入侵严重的地方,可选择补播耐受力强的牧草。

褪黑素浸种对干旱胁迫下白三叶种子萌发和幼苗生长的影响

本研究以‘Haifa’白三叶(Trifolium repens‘Haifa’)为试验材料,探讨了干旱(15%PEG-6000溶液)胁迫下不同浓度(50,100,150,200,250μmol/L)褪黑素(MT)浸种对其种子萌发,幼苗生长与生理特性的影响。结果表明,PEG胁迫显著抑制了白三叶种子萌发和幼苗正常生长;采用50~200μmol/L外源褪黑素浸种均可促进干旱胁迫下白三叶种子萌发,提高干旱胁迫下种子萌发指数,幼苗叶绿素含量、可溶性蛋白含量和SOD活性;且随着褪黑素浓度增加均呈先增后降的趋势。隶属函数分析结果显示,MT浸种对促进干旱胁迫下‘Haifa’白三叶种子萌发的综合作用排序为MT150>MT200>MT100>MT50>MT250,最佳处理浓度为150μmol/L。综上,褪黑素浸种可显著促进干旱胁迫下‘Haifa’白三叶种子萌发和幼苗生长,为进一步在干旱半干旱地区应用褪黑素开展白三叶抗旱管理提供理论依据和技术支撑。

外源赤霉素和褪黑素对三种胁迫下白三叶种子萌发、幼苗生长及生理的影响

为探究外源赤霉素(GA)和褪黑素(MT)对盐、碱和干旱胁迫下白三叶(Trifolium repens)种子萌发、幼苗生长及抗氧化酶的影响,本试验以白三叶‘瑞文德’为试验材料,设置不同浓度(5,10,20,50 mg·L^(-1))GA和(1,2,5,12 mg·L^(-1))MT的处理,测定了3种胁迫下种子萌发、幼苗生长及生理指标。GA和MT可有效缓解盐、碱和干旱胁迫对白三叶种子萌发及幼苗生长的抑制作用,且随着外源物质浓度的升高,各指标呈先升后降的趋势。其中,20 mg·L^(-1)GA显著促进了盐胁迫下白三叶的种子萌发;5 mg·L^(-1)MT显著增加了干旱胁迫下白三叶的胚根长和鲜重;20 mg·L^(-1)GA显著提高了碱胁迫下白三叶的SOD、POD和CAT活性。通过隶属函数分析得出20 mg·L^(-1)GA浸种缓解盐和碱胁迫效果最佳,5 mg·L^(-1)MT浸种缓解干旱胁迫效果最佳。因此,在盐、碱和干旱胁迫条件下,使用20 mg·L^(-1)GA或5 mg·L^(-1)MT浸种能够显著促进白三叶种子萌发和幼苗生长。

白三叶杂交F1代群体的表型鉴定及SSR分析

早期快速鉴定白三叶(Trifolium repens L.)F1杂交子代,获取真杂种对白三叶优良品系的培育和遗传学研究具有重要的意义。本文针对两个白三叶亲本及55个杂交F1的6个表型性状进行分析,绘制聚类热图,再选用3对特异性SSR引物鉴定杂交F1代的真实性。结果表明,在聚类热图中57个株系可以根据亲本的表型性状划分为父本型和母本型。筛选出的19对SSR引物共扩增共得到清晰可辨条带281条,多态性条带137条,多态位点占比为48.41%,每个SSR位点的PIC在18.49%~43.58%之间,平均值为34.73%。其中3对特异性引物在55个杂交后代中共鉴定出53个真杂种,真杂种比率为96.36%,与UPGMA聚类分析结果基本一致。19对SSR分子标记引物具有较高的多态性,可直接用于白三叶遗传多样性分析、杂种鉴定等相关研究,鉴定到的白三叶F1代真杂种为后续育种工作奠定重要基础。

氧化石墨烯对白三叶根系生长、生理和解剖结构的影响

为了探究氧化石墨烯(GO)对植物根系特征的影响,以GO和豆科植物白三叶(Trifolium repens L.)为实验材料,通过将不同质量分数的GO(0.2%、0.4%和0.6%)添加到土壤中,进行为期100 d的植物培养,分析了白三叶根系生长、逆境生理、营养吸收及其解剖结构的响应特征.结果显示:随着GO质量分数的增加,白三叶的根系生长和根系活力显著下降,0.6%GO处理组的根长、直径、体积、干重和根系活力较对照组分别降低了31.2%、35.1%、62.5%、94.1%和64.6%.GO处理后根系的抗氧化酶活性显著增加,矿质营养元素含量随着GO质量分数的升高而降低.根系输导组织的解剖结构参数,包括周皮厚度与细胞层数、导管直径与数量、维管柱宽度、木栓层厚度均随GO质量分数的增加逐渐减小.由此可知,GO会诱导白三叶根系氧化胁迫,激活抗氧化酶系统,抑制根系对矿质营养的吸收,破坏根系输导组织结构,最终抑制了根系生长.

配施有机肥对白三叶草生长及香蕉园土壤生态的改良作用

为探明香蕉园间作白三叶草(Trifolium repens L.)模式下配施纯羊粪和生物有机肥对白三叶草的生物量和营养元素含量及香蕉园土壤理化性质的影响,采用间作白三叶草+常规管理(CK)、间作白三叶草+施用纯羊粪、间作白三叶草+施用生物有机肥3个处理做对比分析。结果表明,间作条件下配施纯羊粪,白三叶草地上部和地下部的生物量分别显著增加17%和10%,地上部和地下部的N、P、K含量分别显著增加21%、33%、17%和13%、15%、53%,土壤有机质、pH、全氮和速效钾含量分别显著增加17%、3%、22%和3%;间作条件下配施生物有机肥,白三叶草地上部和地下部的生物量分别显著增加19%和25%,地上部和地下部的N、P、K含量分别显著增加26%、12%、5%和44%、50%、22%,土壤有机质、pH、全氮和速效钾含量分别显著增加42%、4%、33%和4%。由此可见,在香蕉园间作白三叶草模式下配施纯羊粪或生物有机肥均能显著提高白三叶草的生物量和N、P、K元素含量,同时还能改善香蕉园土壤生态,且配施生物有机肥优于配施纯羊粪。

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。