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1.
【背景】鬼针草属白花鬼针草和三叶鬼针草原产于热带美洲,入侵我国后给生态环境、农业经济等造成严重的危害和影响。目前,关于它们的研究主要针对单个物种。为了更好地理解这2种外来鬼针草的入侵能力和入侵机制,本文开展了这2种入侵种与近缘本地种之间的比较研究。【方法】通过盆栽试验,设置低肥和高肥2个养分水平,测量和计算2种外来鬼针草与近缘本地种金盏银盘在不同土壤养分水平下的形态和生长参数、生物量及其分配、繁殖持续期、单株种子产量以及表型可塑性指数等。【结果】在低肥条件下,除了繁殖持续期和种子产量外,2种外来种和本地种的大多数参数均无显著差异。但在高肥条件下,外来种白花鬼针草的总叶面积、比叶面积、叶面积比、繁殖持续期和种子产量明显高于本地种,而三叶鬼针草总叶面积、比叶面积、总生物量、相对生长速率却显著低于本地种。在对土壤养分的可塑性方面,白花鬼针草在株高、总叶面积、比叶面积、总生物量、叶面积比、相对生长速率、平均叶面积比和种子产量方面的可塑性均高于其他2种植物;三叶鬼针草与金盏银盘相比,大多数参数的可塑性指数较接近。【结论与意义】白花鬼针草是一种入侵能力很强的外来种。长的繁殖持续期和高种子产量是白花鬼针草和三叶鬼针草有别于本地种金盏银盘的重要入侵性状。本研究可为揭示三叶鬼针草和白花鬼针草的入侵机制和影响因素提供依据,并为入侵预测和控制提供基本资料。  相似文献   

2.
为探讨三叶鬼针草(Bidens pilosa)成功入侵机制,利用盆栽试验对不同光照和水分条件下三叶鬼针草与本地种金盏银盘(B.biternata)的生长特征进行了比较研究。结果表明,两物种对光和水的变化均具有较大可塑性,但与金盏银盘相比,在有利环境下三叶鬼针草具有较大的株高、叶面积、生物量;在不利环境下,三叶鬼针草具有较大的比叶面积和叶面积比;除叶面积比和叶生物量比外,三叶鬼针草各生理参数的可塑性指数均高于本地种。这说明三叶鬼针草具有较强的表型可塑性和入侵适应性,这些特性促进了其成功入侵。  相似文献   

3.
[目的]揭示涝渍胁迫下白花鬼针草与其本地近缘种金盏银盘的生长和生理特性差异。[方法]研究对照和涝渍胁迫下白花鬼针草和金盏银盘株高、新生不定根数目、净光合速率(Pn)、总生物量、相对生长速率、叶面积等生长和生理指标的变化。[结果]涝渍胁迫后入侵植物白花鬼针草比本地种金盏银盘保持了更高的株高、新生不定根数目和PnP<0.01),更高的总生物量、相对生长速率、根生物量、茎生物量、叶生物量、叶面积(P<0.05)。涝渍胁迫10 d内,白花鬼针草根系活力和光系统II最大光量子产量显著高于金盏银盘(P<0.05),涝渍胁迫20 d后2物种的2个参数趋于一致,这些结果表明涝渍对白花鬼针草生长的负面影响较小。涝渍胁迫前期更快的不定根生长速度和更高的根系脱氢酶活力可缓解涝渍对白花鬼针草的胁迫,减少了涝渍对光合系统的破坏,使其保持更高的Pn,从而有助于白花鬼针草保持更高的生长速率,是白花鬼针草耐受涝渍的生理机制。[结论]与本地近缘种金盏银盘相比,短期涝渍可使入侵植物白花鬼针草形成生长优势,华南地区雨季短期集中降水所形成的土壤涝渍有利于白花鬼针草的入侵。全球气候变化造成的降水不平衡性可能会加剧白花鬼针草在华南地区的入侵。  相似文献   

4.
入侵植物三叶鬼针草(Bidens pilosa)是与农作物竞争的恶性杂草,而我国鲜有对其入侵能力的系统总结。作者综述了三叶鬼针草及其近缘本地种金盏银盘在不同环境下表型可塑性的研究进展,比较了两者在不同光照和温度、不同埋土深度的种子萌发概况,不同光照、水分、温度及土壤养分环境条件下幼苗生物量分配特点及其繁殖特性,阐明了三叶鬼针草成功入侵的机制包括快速繁殖能力、较广的生态适应性、根系分泌物的化感作用等。最后,对三叶鬼针草未来的研究进行了展望,并总结了三叶鬼针草的防控策略。  相似文献   

5.
【目的】理解氮素增加对入侵植物与近缘共存本地植物生长和竞争的影响,可为预测全球氮沉降背景下入侵植物的风险评价和本地植物的保护提供依据。【方法】为模拟氮沉降,设置对照(无氮添加)、低氮(1 g·m-2·a-1)和高氮(5 g·m-2·a-1)添加3种处理,将入侵植物鬼针草及其近缘共存的本地植物金盏银盘分别单种和混种,比较它们在各处理下的生长(株高、分枝数和生物量等)和竞争[相对优势度指数(RDI)与相对互作强度指数(RII)]情况。【结果】无论有无竞争,高氮添加均显著增加鬼针草的生物量,降低其根冠比;无竞争时,高氮添加还显著增加其株高和分枝数。但高氮添加仅显著增加金盏银盘无竞争时的生物量。在所有氮处理下,鬼针草的RDI和RII均显著大于金盏银盘。高氮添加显著增加鬼针草的RDI,但其RII在所有氮处理间无显著差异;高氮添加显著降低金盏银盘的RDI和RII。【结论】高氮更利于鬼针草的生长,其在所有氮素处理下均有较强的竞争力和竞争耐受性,且高氮处理下竞争力更强。因此,全球氮沉降增加会加剧鬼针草对近缘本地植物的竞争抑制和入侵风险。  相似文献   

6.
【目的】黄顶菊、三叶鬼针草和豚草是我国危害较严重的3种菊科入侵植物。了解3种菊科植物生长过程中土壤养分和酶活性的变化,可以为研究其入侵机制提供依据。【方法】在中国农业科学院植物保护研究所廊坊中试基地开展同质园实验,比较分析了黄顶菊、三叶鬼针草和豚草3种菊科入侵植物在幼苗期、旺盛生长期和生殖生长期根际土壤养分和酶活性的变化。【结果】3种外来菊科植物的生长时期对土壤养分和酶活性存在显著影响。3种外来植物入侵域的土壤速效磷、硝态氮含量以及磷酸酶活性随生长时期变化都表现出先升高后降低的趋势,均在旺盛生长期达到最大值。入侵域土壤速效磷和硝态氮含量的变化趋势与狗尾草明显不同。3种外来植物入侵降低了土壤速效钾含量,提高了土壤脲酶、磷酸酶活性。【结论】3种外来菊科植物的入侵改变了土壤养分和酶活性,创造出更有利于自身生长和繁殖的条件,以利于其进一步扩张。  相似文献   

7.
入侵植物繁殖性状的研究可为揭示植物入侵机制提供重要的科学依据。为研究土壤养分对入侵植物和本地植物繁殖性状的影响, 并进一步研究养分添加是否更能促进入侵植物的繁殖能力, 我们设置了低、高两个养分水平, 通过同质园实验比较了不同土壤养分对假臭草(Praxelis clematidea)、胜红蓟(Ageratum conyzoides)、三叶鬼针草(Bidens pilosa) 3种菊科一年生入侵种和夜香牛(Vernonia cinerea)、一点红(Emilia sonchifolia)、墨旱莲(Eclipta prostrata) 3种本地种繁殖性状的影响。研究结果显示, 养分添加提高了6种菊科植物的开花株高、株高、地上生物量、单粒种子重量、总花序数、每花序种子数、总种子数量、总种子重量, 并使开花时间提前、花期延长。养分添加对入侵种的开花株高和单粒种子重量的提高幅度要比本地种更显著。相对于部分本地植物(夜香牛、墨旱莲), 养分添加更能促进部分入侵植物(假臭草、胜红蓟)的繁殖能力。三叶鬼针草和一点红的总种子数量和总种子重量在两种土壤养分水平下均较小。本地种墨旱莲的总种子数量和总种子重量在低养分条件下高于3个入侵种。这些结果表明, 高土壤养分仅能促进部分入侵植物相对于部分本地植物的繁殖能力。  相似文献   

8.
为探讨鬼针草属(Bidens)入侵种的入侵性,利用同质园种植实验比较了该属入侵种三叶鬼针草(Bidens pilosa)和大狼耙草(B.frondosa)与本地种金盏银盘(B.biternata)和狼耙草(B.tripartita)在光照与水分交互作用下的形态、生长、生物量分配、光合特征及其表型可塑性的差异。结果表明:入侵种的株高和生物量在低光低水条件下与本地种相似,在有利的光照和水分条件(高光高水)下显著高于本地种,相对生长速率在高光条件下均高于本地种。入侵种在高光处理下增加了对地下部分的资源投入,在低光处理下增加了对叶的投入,且低光低水条件下比叶面积显著高于本地种。这些特性可能提高了入侵种对资源的捕获和利用能力,使其既能耐受不利的环境,又能在有利的条件下表现最大化。入侵种和本地种的形态、生长和光合生理等参数对水分变化的可塑性指数均较小,对光照变化的可塑性指数均较大。入侵种的多数变量对光照响应的可塑性指数大于本地种,较大的表型可塑性可能促进其成功入侵。另外,入侵种和本地种的光合生理参数无显著差异。相对于光合特征,形态、生长、生物量分配和表型可塑性等可能对鬼针草属入侵种的入侵性更为重要。  相似文献   

9.
利用温室盆栽试验,研究了不同光强100%、40%、20%和5%下三叶鬼针草营养生长期和繁殖期的生长特征。结果表明:中度遮荫有利于三叶鬼针草支持结构的生长和营养期的物质积累,重度遮荫下仍能生长良好。在两个生长时期,相对生长速率(RGR)、净同化速率(NAR)均在100%光强下最大,5%光强下最小;总生物量在营养期和繁殖期分别在40%光强和全光照下最大,在3%光强下最小;株高、总叶面积(TLA)、根生物量比(RMR)、根冠比(R/C)、叶生物量比(LMR)、比叶面积(SLA)、叶面积比(LAR)、平均叶面积比(LARm)在3%光强时均大于全光照下的;支持结构生物量比(SBR)在40%光强、20%光强下大于3%光强和全光照处理。这说明三叶鬼针草在形态、生物量分配及生长特性上对光因素具较强的可塑性,这可能是其分布范围广、具有强入侵性的因素之一。  相似文献   

10.
张静  闫明  李钧敏 《生态学报》2012,32(10):3136-3143
生物入侵严重影响了生态系统的结构和功能。菟丝子属植物可以有效地抑制入侵植物的生长,恢复本地群落,是一种有效的生物防治剂。本文以本地寄生植物南方菟丝子(Cuscuta australis)和三叶鬼针草(Bidens pilosa L.)为研究对象,采用不同数量的南方菟丝子茎段(长度15cm)寄生入侵植物三叶鬼针草来形成不同的寄生程度(寄生I、II、III分别由1、2、3段南方菟丝子茎段寄生),分析不同程度的寄生对寄主三叶鬼针草补生长的影响,并探讨寄生植物对寄主补偿生长的诱导。南方菟丝子寄生34d之后,三种程度的寄生均可显著抑制三叶鬼针草生长。寄生III处理组的南方菟丝子生物量显著大于寄生I和寄生Ⅱ处理组。不同寄生强度对三叶鬼针草生长的影响具有一定的差异。寄生II和寄生III的三叶鬼针草叶生物量、茎生物量、地上生物量、地下生物量、总生物量、株高与冠幅均显著低于寄生I,但相互之间不存在显著性差异;寄生II的三叶鬼针草的叶面积、根长和根体积均显著低于寄生I,寄生III的叶面积和根长高于寄生II,但与寄生I及寄生II之间不存显著性差异,寄生III的根体积显著高于寄生II,但与寄生I之间不存在显著性关异。与对照相比,不同程度寄生下三叶鬼针草的NAR和RGR极显著降低。寄生II的三叶鬼针草的RGR显著低于寄生I,寄生III的三叶鬼针草的RGR高于寄生II,但与寄生I及寄生II之间均不存在显著性差异。寄生II与寄生III的三叶鬼针草的NAR显著低于寄生I组,但相互之间不存在显著性差异。除寄生I处理组外,寄生II与寄生III处理导致三叶鬼针草与南方菟丝子的累积生物量均显著低于对照。寄生II处理组的累积生物量要低于寄生I处理组,寄生III处理组的累积生物量要高于寄生II处理组,但显著低于对照组,表明寄生III处理组的三叶鬼针草产生了低补偿生长。由于南方菟丝子寄生显著抑制入侵植物的生物量,因此南方菟丝子仍具有防治入侵植物的潜力。  相似文献   

11.
Phenotypic plasticity is an important plant trait associated with invasiveness of alien plants that reflects its ability to occupy a wide range of environments. We investigated the phenotypic response of Chenopodium murale to resource variability and ontogeny. Its plant-level and leaf-level traits were studied at high-resource (HR) and low-resource (LR) sites in peri-urban areas in Indian dry tropics. Plants at LR had significantly higher root length, root/shoot biomass ratio, stem mass and root mass fractions. Plants at HR had higher shoot length, basal diameter, leaf mass fraction and leaf area ratio. Leaf-level traits like leaf area and chlorophyll a were also higher here. Mean plasticity indices for plant- and leaf-level traits were higher at HR. With increasing total plant biomass, there was significant increase in the biomass of leaf, stem, root, and reproductive parts, and root and shoot lengths, whereas root/shoot length ratio, their biomass ratio, and leaf and root mass fractions declined significantly. Allocation to roots and leaves significantly decreased with increasing plant size at both sites. But, at any size, allocation to roots was greater at LR, indicative of optimization of capture of soil nutrients, whereas leaf allocation was higher at HR. Consistently increasing stem allocation equaled leaf allocation at comparatively higher shoot lengths at HR. Reproductive biomass comprised 10–12% of the plant’s total biomass. In conclusion, the success of alien weed C. murale across environmentally diverse habitat conditions in Indian dry tropics can be attributed to its high phenotypic plasticity, resource utilization capability in low-resource habitats and higher reproductive potential. These characteristics suggest that it will continue to be an aggressive invader.  相似文献   

12.
The allometry of greenhouse‐grown Salsola collina Pall. in response to variation in soil nutrient content, water supply and population density has been compared. The results showed that the biomass allocation was size‐dependent. Root, stem, leaf and reproductive allocation showed a ‘true’ plasticity in response to soil nutrient variation. At low soil nutrient content, plants tended to allocate more biomass to the development of reproductive organs than to stem and leaf, but root allocation was consistent due to a tradeoff between the effects of plant size and soil nutrient content. The plasticity of stem allocation and reproductive effort was ‘true’, while the plasticity of root allocation was ‘apparent’, but there was no plasticity for leaf allocation in response to soil water variation. At lower soil water content, plants tended to allocate more biomass to the stem than to development of reproductive organs. With the exception of ‘apparent’ plasticity of root allocation, no plasticity was detected in biomass allocation when population density was varied.  相似文献   

13.
Spatial and temporal dynamics of biomass allocation within and between organs were investigated in seedlings of two birch species of contrasting successional status. Seedlings of Betula alleghaniensis Britt (yellow birch) and B. populifolia Marsh (gray birch) were grown for 6 weeks at two nutrient levels in rectangular plexiglass containers to allow non-destructive estimates of root growth, production and loss. Leaf area and production were simultaneously monitored. Yellow birch responded more to nutrient level than gray birch in terms of total biomass, shoot biomass, leaf area and root length. Yellow birch also flexibly altered within-organ allocation (specific leaf area, specific root length and specific soil amount). In contrast, gray birch altered between-organ allocation patterns (root length:leaf area and soil amount:leaf area ratios) more than yellow birch in response to nutrient level. Yellow birch showed greater overall root density changes within a very compact root system, while gray birch showed localized root density changes as concentric bands of new root production spread through the soil. Species differ critically in their responses of standing root length and root production and loss rates to nutrient supply. Early successional species such as gray birch are hypothesized to exhibit higher plasticity in varied environments than later successional species such as yellow birch. Our results suggest that different patterns of allocation, within and between plant organs, do not necessarily follow the same trajectories. To characterize thoroughly the nature of functional flexibility through ontogeny, within- and between-organ patterns of allocation must be accounted for.  相似文献   

14.
The role of phenotypic plasticity in plant invasions is among the most often discussed relationships in invasion ecology. However, despite the large number of studies on this topic, there is little consistency. Reconsideration of the role of plasticity by distinguishing two substantially distinct trait-groups, performance traits (contributing directly to fitness) and functional traits (influencing fitness indirectly), could form a more operative framework for comparative studies. In the current study we expect that invasive species benefit from being plastic in functional traits, which allows them to maintain a more constant performance across different environmental conditions compared to non-invasive alien species. We compared invasive and naturalized non-invasive alien plant species by their germination (20 species), their vegetative (10 species) and their reproductive (four species) responses to three different levels of water, light and nutrient availability in a common garden experiment. Used traits were classified into performance (germination ratio, total biomass, seed number) and functional traits (time to germination, root:shoot ratio, specific leaf area, reproductive allocation). We found that invasive and non-invasive species responded similarly to environmental factors, except for example that invasive species germinated earlier with decreasing light conditions or, surprisingly, non-invasive species reacted more intensely to increased nitrogen availability by having a superior ability to achieve greater biomass. The two groups were equally plastic in all the germination and vegetative traits measured but the reproductive traits, since higher plasticity in relative reproductive allocation and higher constancy in reproductive performance showed a pronounced relation with invasiveness.  相似文献   

15.
模拟在喀斯特异质生境下,通过随机区组实验,研究三叶鬼针草(Bidens pilosa L.)在两种土壤生境(浅而宽、深而窄)和3种水分处理(对照、减水50%、减水70%)下植物的地上和地下生长关系及生物量分配格局。结果显示:(1)两种生境中三叶鬼针草的地上生长(株高、地径、叶面积、叶生物量)与地下根系生长(根长、根表面积、根体积、根生物量)均随着施水量的减少而降低;叶面积比率随着施水量的减少而增加;根质量比在浅而宽土壤生境中呈先增后减的趋势,而在深而窄土壤生境中呈增加趋势。(2)两种生境中三叶鬼针草的地上生物量与地下根系生物量、叶面积与根长、叶面积与各层根系生长均呈显著正相关关系。但在浅而宽土壤生境中,三叶鬼针草的地上生物量与各土层根系生物量均呈显著正相关,而在深而窄土壤生境中,地上生物量仅与中上土层根系生物量呈显著正相关。研究表明三叶鬼针草在不同生境中均具有较好的地上地下协同生长对策,在增强对地下资源获取的同时也增强了对地上资源的获取。在浅而宽土壤生境中,三叶鬼针草通过协调根系的横向拓展能力与植物叶片的生长来应对快速的干旱缺水;在深而窄土壤生境中,植株能较好地协调根系向下拓展能力与地上叶面积的生长,更好地利用土壤深层的水分资源。  相似文献   

16.
对密云水库北京集水区板栗林主要养分元素循环进行了研究。结果表明,22年生板栗林的生物量为38638kg·hm-2;板栗林5种主要养分元素N、P、K、Ca、Mg贮存量为315.38kg·hm-2,各器官中5种元素贮存量大小排序是干>枝>根>叶>花>果苞>果。板栗林生态系统乔木层每年从土壤中吸收的5种养分元素量为79.17kg·hm-2,吸收量占0~30cm土层5种养分元素总量的0.15%,占0~30cm土层中5种元素有效养分量的1.95%。年吸收量中存留量为11.25kg·hm-2,枯落物归还量为58.08kg·hm-2。雨水及雨水淋溶输入到板栗林生态系统的养分元素量为38.63kg·hm-2,果实输出量为9.84kg·hm-2。雨水和雨水淋溶量与枯落物归还量之和大于吸收量,表明研究期间板栗林生态系统养分元素的收入略大于支出,5种元素的吸收系数排序为N>P>K>Ca>Mg,利用系数排序为K>N>Mg>P>Ca。循环系数排序为K>N>P>Mg>Ca。周转期排序是Ca>P>Mg>N>K。  相似文献   

17.
Question: Invasive alien plants can affect biomass production and rates of biogeochemical cycling. Do the direction and intensity of such effects depend upon the functional traits of native and alien species and upon the properties of the invaded habitat, with the same alien species having differing impacts in different habitats? Location: Lowlands of Switzerland. Methods: Fourteen grassland and wetland sites invaded by Solidago gigantea and widely differing in biomass production and soil P availability were surveyed. To determine whether the impact of the species was related to site fertility, we compared the invaded and native vegetation in terms of biomass, species composition, plant traits and soil properties. Results: S. gigantea generally increased the above‐ground biomass production of the vegetation and soil C content, while reducing nutrient concentrations in biomass and N availability in the soil. However, it had no significant effect on plant species richness, soil respiration, soil pH and P availability. Leaves of S. gigantea had a greater C content than those of native species; other leaf traits and root phosphatase activity did not differ significantly. Conclusions: Our results suggest that a conservative nutrient‐use strategy allows S. gigantea to invade a broad range of habitats. The observed effects of invasion did not vary according to biomass production of the invaded sites, but some effects did depend on soil P availability, being more pronounced at more P‐rich sites. Thus, the full range of invaded habitats should be considered in studying the potential impact of plant invasions on ecosystem processes.  相似文献   

18.
植物对邻体根系的表型可塑性是指与无邻体对照相比, 即使个体平均可获取土壤资源相同, 在有邻体根系存在时植物也会改变根系生物量分配, 并影响其他功能性状和适合度。表型可塑性进化假说(evolution of plasticity hypothesis)认为外来植物在入侵地进化出了更强的表型可塑性。对该假说的验证多集中于外来植物对光照、水分、养分以及天敌等的可塑性进化, 但对邻体根系的可塑性在入侵植物中是否发生进化尚未见报道。我们采用同质园实验比较了喜旱莲子草(Alternanthera philoxeroides)入侵地(美国)和原产地(阿根廷)各5个基因型的适合度与功能性状对同基因型邻体根系的可塑性。结果表明: 喜旱莲子草的根冠比(P = 0.088)和比叶面积(P = 0.007)对同基因型邻体根系的可塑性在入侵地和原产地基因型间存在差异: 入侵地基因型在有邻体根系时根冠比和比叶面积增加, 而原产地基因型则相反。但是, 总生物量、贮藏根生物量、比茎长和分枝强度对邻体根系的可塑性在入侵地和原产地间没有显著差异。此外, 与分隔邻体根系相比, 同基因型邻体根系存在时总生物量(+9.9%)和贮藏根生物量(+13.9%)显著增加, 比茎长(-9.5%)显著降低。最后, 与原产地基因型相比, 总体上入侵地基因型的总生物量(+62.0%)和贮藏根生物量(+58.9%)增加, 比茎长(-28.5%)和分枝强度(-42.8%)降低。这些结果表明喜旱莲子草入侵地基因型与资源利用相关功能性状(如根冠比和比叶面积)对邻体根系的可塑性方向与原产地基因型相反; 但适合度和株型相关性状(如比茎长和分枝强度)对同基因型邻体根系的可塑性与原产地没有差异。  相似文献   

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