【作者】 蒋华伟；

【导师】 郭水良； 方芳；

【作者基本信息】 浙江师范大学 ， 植物学， 2008， 硕士

【摘要】 加拿大一枝黄花（Solidago canadensis L.）原产北美,菊科一枝黄花属植物,20世纪30年代作为观赏植物引种到我国上海、南京等地,20世纪80年代起开始蔓延成为我国东部地区危害严重的杂草。其扩张速度十分惊人,成为一种典型的外来入侵种,已经被列入中国重要外来有害植物名录。加拿大一枝黄花既能进行有性繁殖又能进行无性繁殖,在入侵过程中,加拿大一枝黄花可以通过种子繁殖先形成多个“卫星式”种群,后通过地下茎克隆繁殖填充空隙,最终形成单优势种群排挤本地植物。拿大一枝黄花的危害引起了国内专家学者的极大重视,为控制其危害,在其生理生态适应性、化学他感作用,遗传变异等方面做了大量的研究。本文主要研究了加拿大一枝黄花对环境因子土壤水分、光照强度的适应性特点及其种群分布格局,同时在生物、化学和机械控制方法进行了探索,为预测其潜在入侵地及其防除策略提供一定的科学依据。主要结果如下:1.采用盆栽法研究了加拿大一枝黄花幼苗生长对土壤水分和光照强度的响应。结果表明:（1）中生、弱光（15%）环境有利于幼苗株高的增加,而在旱生、强光（100%）环境下株高最低;（2）叶片数在湿生条件下达到最大值;光照强度对加拿大一枝黄花叶片数的影响较小,各光照处理之间无显著性差异;（3）土壤水分和光强对叶面积均有较大影响,水生环境下的叶面积最小,在中生条件下达到最大值;中等光强时叶面积最大,强光（100%）和弱光（15%,5%）都不利于叶面积的增加;（4）比叶重在水分处理下无显著差异,但是随着光照强度的增大而增大,加拿大一枝黄花比叶重的变化,是适应光强的变化的途径之一;（5）加拿大一枝黄花幼苗的生物量在中生环境下达到最大值,水生环境下最小;在光照处理中,45%的光照最适合加拿大一枝黄花生物量的积累,而弱光（5%）下生物量几乎没有增加,植株最终死亡。2.采用连续小样方法调查了加拿大一枝黄花的在不同定居阶段和生境中的盖度,以及以盖度为指标进行了其种群的分布格局研究。结果表明,加拿大一枝黄花种群呈明显的集群分布,随着其在新生境中定居年龄的增长,其种群斑块呈由少→多→少的变化趋势;加拿大一枝黄花种群斑块的这种变化趋势,与其以有性繁殖形成的种子苗为定居者,到定居后形成的无性克隆填充斑块间的间隙有关。3.在实验控制条件下,观测了日本菟丝子（Cuscuta japonica）寄生后加拿大一枝黄花生理生态特性的相关指标,并对寄主进行了解剖观察,探讨了应用日本菟丝子防除加拿大一枝黄花的可行性。结果表明:（1）日本菟丝子能够寄生于加拿大一枝黄花的茎及叶片,寄生根能够穿过加拿大一枝黄花表皮、皮层直至髓部,从寄主植株吸收水分和养分,使自身生物量得到增加,从而严重影响了加拿大一枝黄花的生长;（2）寄生50～60d后,加拿大一枝黄花植株最大光合速率只有对照的58.81%,而光合补偿点则为对照的153.39%;脯氨酸和丙二醛含量分别为对照的2.88和1.29倍,可溶性蛋白、可溶性总糖含量则分别下降了43.45%、44.47%;（3）在浙江金华地区,自然条件下生长的加拿大一枝黄花一般在九月中旬现蕾,十月中旬进入盛花期,而被寄生的植株直到十月下旬才开始现蕾,花序长度不到正常植株的10%,当菟丝子生物量（干重）超过加拿大一枝黄花植株的13.14%时,植株不能开花结实。从实验结果看,日本菟丝子寄生可以严重影响加拿大一枝黄花的营养生长和开花结实。因此,利用日本菟丝子有望成为控制加拿大一枝黄花危害的一种辅助手段。4.在加拿大一枝黄花开花期采集花粉,实验室条件下测定了加拿大一枝黄花的花粉活力及草甘膦、乙稀利、2,4—D和百草枯4种除草剂对花粉萌发的影响,结果表明:适合加拿大一枝黄花花粉萌发的培养基为0.5%琼脂+20%蔗糖+10mg·L^-1硼酸,萌发率达50%以上;在常温下,加拿大一枝黄花花粉能存活3-4天;在培养基中加入适当浓度的Ca²⁺对花粉萌发率无明显影响,但是可以促进花粉管的生长;不同农药对花粉萌发及花粉管生长的抑制效果依次为草甘膦＞乙稀利＞2,4—D＞百草枯。5.为了了解加拿大一枝黄花对不同人为干扰的响应,实验设置了不同的干扰类型,喷施除草剂（草甘膦和2,4-D）、对地下根状茎不同强度的切割、自然失水、沤制处理、对地上部分进行不同强度的切割处理。结果表明:（1）加拿大一枝黄花对内吸性除草剂草甘膦(11250—22500 g.ha^-1)的敏感性高于2,4-D(450—1050 g.ha^-1),表明前者有更好的防治效果;（2）地下茎在不同月份的繁殖能力不同,其中2、3月份地下茎的繁殖能力最强,而11、12月份的繁殖力较低;（3）随着地下根状茎体内水分的减少,其成活率逐渐降低,当失水超过鲜重的50%时,其成活率锐减。因此,在晴天干燥时对加拿大一枝黄花入侵地进行翻耕处理有利于根除地下根状茎;（4）加拿大一枝黄花地下根状茎在积水环境下,能忍受短期的低盐处理,有较广的pH值适应范围。但是,高温且积水环境有利于控制加拿大一枝黄花地下根状茎的生长,30℃下沤制5天根状茎会丧失生命活力;（5）在加拿大一枝黄花营养生长早期,进行不同强度的人为干扰对其后期生长及有性繁殖的影响不大,营养生长中期即五月份左右受到干扰其分枝数及种子产量都大大增加,开花前期受到轻度干扰可强烈刺激其分枝和有性繁殖。更多还原

【Abstract】 Solidago canadensis（Canada goldenrod）,a rhizomatous perennial plant （family,Compositae）originating from North America,was introduced into China as a horticultural plant in 1930s.S.canadensis began to spread rapidly as an important weed in the 1980s and has now infested many districts in eastern China and the species was listed as one of the harmful alien plants in China.In the process of invasion,S.canadensis initially forms numerous "satellite model" populations,produces clones of individual plants with the aid of the underground rhizomes to fill the interspace,and,finally,forms a single dominant species population supplanting the native species.It has caused grievous damages to the ecosystems.In recent years,the studies and control of S. canadensis have been paid more attention in China.To date,the research on S. canadensis has mainly focused on its physio-ecological adaptation,allelopathic effects on native plants and the genetic diversity.In this paper,we studied the ecological adaptability of S.canadensis to the soil water content,light intensities, the distribution pattern of its populations,and the the methods of its biological control,chemical control and physical controls.The main results are as follows:1.The growth response of the seedling of S.canadensis to the water content in the soils and light intensities were determined under controlled conditions.We found:（1）The seedling height of S.canadensis was affected greatly by water content in the soils and light intensities,mesophytic habitats and habitats with lower light intensity are good for the species to increase its height,while xeric habitats and habitats with higher light（100%）are not;（2） The leaf number of S.canadensis reached maximum when it grew in moist habitat,but was less affected by the light intensities.（3）Soil water content has greatly effect on the leaf area of S.canadensis,which reached the biggest when it grew in the mesophytic,habitat,but smallest in the aquatic habitat.The habitats with moderate light intensity（45%）are good for S.canadnesis to increase the leaf area,but those with high light intensity（100%）or low light intensity（15%,5%）are not.（4）The indices of leaf mass per area are not significant different among the plants growing in the soils with different water contents,but increased with the increase of the light intensity;（5）The biomass of the seedlings reached maximum in the mesophytic habitat,but with the minimum in the aquatic habitat.The habitat with 45%light intensity is best for the biomass accumulation of S.canadensis,while the seedlings in the habitat with 5%light intensity almost did not grow and perished at last.2.The coverages of S.canadnesis populations in different colonized periods and habitats were surveyed by the successive sampling.The deviation coefficients were calculated and the pattern scale and pattern grain were analyzed.The results showed:（1）The populations of S.canadensis were obvious clumpy distributed;（2）The number of the population patches of S. canadensis followed an order as less→more→less,which was related to its sexual reproduction at initiatory invaded period and asexual reproduction at latter period.3.The eco-physiological indices of S.canadensis after being parasitized by C.japonica were measured under the experimental conditions,and the anatomical features of the parasitism were also observed.The main results were as follows:（1）the parasitic roots of Cuscuta japonica were able to parasitize the stems and leaves of S.canadensis by penetrating the stem and leaf epidermis to the pith of S.canadensis,and therefore,absorb a large amount of water and nutrition from the host,which enhanced its biomass and stunt the host;（2）after being parasitized for 50 to 60 days,compared with the control,the maximal net photosynthesis rate of S.canadensis decreased to 58.81%,the light compensation increased by 153.39%,the proline by 287.57%,and MDA content by 128.64%;but the content of dissoluble protein and sugar declined 43.45% and 44.47%respectively;（3）the normal individuals of S.canadensis entered into flower bud stage in the middle of September,and full flowering stage in the middle of October;in contrast,those parasitized by C.japonica produced flower buds late to the end of October,and their inflorescence length was only one-tenth of the controls.The dividuals of S.canadensis were unable to produce flower buds if the biomass（dry weight）of its parasitic plant（namely,C. japonica）exceeded 13.14%of its dry weight.The results above showed that C. japonica could restrain the growth and sexual reproduction of S.canadensis effectively.Therefore,C japonica might be a promising species for controlling the invasiveness of S.canadensis.4.We collected the pollens of S.canadensis in its anthesis,examined the activety of pollen and the influences of herbicides（Glyphosate,Ethephon,2, 4-D,Paraquat）on pollen germination and pollen tube growth.We found:（1）the culture medium containing 0.5%agar,20%sucrose and 10 mg·L^-1boracic acid was favorable for the pollen germination and the pollen tube growth of S. canadensis,and the pollen germination rate is higher than 50%,the pollens of S. canadensis survived for 3-4 d under natural conditions;the culture medium with proper concentration of Ca²⁺has no effects on pollen tube germination,but accelerated the growth of pollen tube distinctly.Based on their inhibitory effects （from high to low）on pollen germination and pollen tube growth,the 4 herbicides are ranked as Glyphosate＞Ethephon＞2,4-D＞Paraquat.5.In order to better understand the response of S.canadensis to human disturbance,we determined:（1）the content of chlorophyll,Proline,MDA, conductivity of leaves of S.canadensis after sprayed with herbicides;（2）the survival and reproductive capacity of its rhizomes under different incision intensities,dry and waterlogged treatments;（3）its shoot number,capability of sexual reproduction of S.canadensis after cut at different intensities in different stages.We found:（1）Glyphosate(11,250-22,500g.ha^-1)is more effective than 2,4-D(450-1050g.ha^-1)in the control of S.canadnesis;（2）The vegetative reproductive capacity of its rhizomes varies among different stages,with highest from February to March and lowest from November to December,suggesting that the period from November to December is a good stage to control S. canadensis by mechanical methods;（3）With the decrease of water content in rhizomes,their survival rate falls gradually;When the water in rhizomes lost by over 50%of the fresh weight,their survival rate falls sharply.Therefore,tillage in dry and sunny period is a good practice to control the rhizome of S. canadensis;（4）Under soakage condition,the rhizome of S.canadensis could stand short-term stress of low concentration of salt solution,has wider adaptation breadth to pH,especially high tolerance to the acid environment;thus the soakage of the rhizome at temperature of 30℃（Rice/dry crop rotation Systems）is a choice for us to control rhizome of S.canadensis;（5）Little effect on the growth and sexual reproduction of S.canadensis could be found if the plant cut with different intensities at the early stages of vegetative growth;but, in its middle stage of the vegetative growth,for instance,May,the number of its shoots and seeds would increase greatly;the shoot number and seeds could increase more if the plants cut with light intensity before inflorescence.The above results provided new and practical information in the control of S. canadensis.更多还原