【作者】 王勇；

【导师】 曹同； 郭水良；

【作者基本信息】 上海师范大学 ， 水生生物学， 2008， 硕士

【摘要】 外来植物春一年蓬(Erigeron philadelphicus)是我国境内的新入侵植物,在上海郊区已普遍分布,局部区域形成危害。为有效地预测该外来植物的入侵潜力和生态风险,本文从种群和群落生态学、抗逆生理学、繁殖生物学、根系特点和化学防治等方面,研究了春一年蓬的入侵生物学问题。主要研究结果如下:(1)野外调查了上海市郊261个样地早春杂草的生态重要值,共计出现106种杂草,计测了其中84种主要杂草的生态位宽度和生态位重叠值。以生态位重叠值为指标,采用主坐标排序法对84种主要杂草的生态位重叠关系进行了二维排序,并分析了春一年蓬与主要伴生种的生态位重叠关系。结果表明:①春一年蓬的生态位宽度为0.1768,比春一年蓬生态位宽的伴生杂草有猪殃殃Galium aparina (0.4419)、加拿大一枝黄花Solidago canadensis(0.3413)、刺果毛茛Ranunculus muricatus(0.3362)、野胡萝卜Daucus carota(0.2997)、大巢菜Vicia sativa(0.2974)、泽漆Euphorbia beliocopia(0.2970)、荠菜Capsella bursa-pastoris(0.2923)、野塘蒿Conyza bonarinisis(0.2780)、波斯婆婆纳Veronica persica(0.2556)、葎草Humulus scandens(0.2361)、野老鹳草Geranium carolinianum(0.2360)、鹅观草Roegneria tsukushiense(0.1997)和羊蹄Rumex japonicus(0.1906)等,看麦娘Alopecurus aequalis(0.1776)、蚊母草Voronica peregrina(0.1669)与春一年蓬的相近,续断菊Sonchus asper(0.1598)、苦苣菜Sonchus oleraceus(0.1485)、通泉草Mazus pumilus(0.1450)和牛繁缕Stellaria uliginosa(0.1393)的生态位宽度比春一年蓬的要小,这20种杂草也是本地区生态适应性强,危害相对较重的杂草种类。②与春一年蓬生态位重叠较大的有:续断菊(0.501)、羊蹄(0.480)、野塘蒿(0.471)、野老鹳草(0.356)、蔊菜(0.347)、看麦娘(0.327)和加拿大一枝黄花(0.318)等杂草。③从春一年蓬与其他主要早春杂草生态分布相似性的CCA排序图上可以看出,春一年蓬与上述菊科外来杂草位于排序图相近的区域,这说明菊科杂草在入侵生境方面的极大相似性,分布于较为干旱、人为干扰强的空阔地带。(2)测定了不同环境胁迫下营养生长时期春一年蓬的膜相对透性、叶绿素、丙二醛、游离脯氨酸和可溶性糖的含量以及过氧化物酶的活力。与5℃和22℃处理相比,35℃处理的春一年蓬植株的膜相对透性、丙二醛含量、脯氨酸含量最高。用pH 7的溶液处理的春一年蓬植株,其体内的膜相对透性,丙二醛、游离脯氨酸和可溶性糖含量要低于用pH 10或pH 4的溶液处理的植株。随着其生长环境中NaCl含量的增加,丙二醛、游离脯氨酸和可溶性糖的含量以及膜相对透性也相应地增加。而且,膜相对透性和丙二醛含量与土壤NaCl含量呈明显的正相关。春一年蓬叶片组织内含水量附着土壤环境中的含水量的下降而减少,这导致了其丙二醛、可溶性糖和游离脯氨酸和膜相对透性的增加。也就是说,干旱胁迫导致了春一年蓬产生更多的丙二醛、可溶性糖和游离脯氨酸。以上结果可以得出以下结论:①与高温环境(35℃)相比,春一年蓬更适合于生长于低温(5℃)的环境;②中生或湿性环境适合于春一年蓬生长,过酸(PH 4)或过碱环境(pH 10)均会对春一年蓬产生有害影响;③春一年蓬对土壤中的NaCl比较敏感;④春一年蓬具有一定抗旱能力。(3)通过种子萌发、幼苗和幼根生长实验,初步研究了春一年蓬地上部分水提液、地下部分水提液、地上部分乙醇提液对4种受体作物油菜、长梗白菜、番茄、黄瓜的化感作用,同时采用索氏提取法提取春一年蓬地上和地下部分粗提物并进行GC-MS分析。结果表明:①不同提取方式下的浸提液对作物种子的最终萌发率和幼根生长具有显著的抑制作用,且随着溶液浓度的升高抑制作用不断增强。②不同提取方式下的浸提液对幼苗生长的影响表现为低促高抑的双重效应。③春一年蓬地上部分和地下部分粗提物经GC-MS分析共鉴定出28种化合物,包括酸、醇、醛、酮、酯、萜等,其中酸、酮、酯、萜类是其主要化感成分。(4)通过对不同采样点的春一年蓬体内的5种重金属元素含量测定,发现不同器官对重金属的富集吸收能力有所不同,其中根对Cu、Cd、Cr的富集能力较强,富集系数接近或超过1,茎和叶对Cu、Cd也有较强的富集能力。不过春一年蓬对Pb、Zn的富集能力相对较弱些,尤其是对Pb的富集系数均小于0.50。5种重金属元素在植物体内的平均含量大致遵循根>叶>茎的规律。(5)通过对春一年蓬的种子有性繁殖指标的测定发现,春一年蓬的种子千粒重在0.033±0.003 g,种子含水量70.573±5.871%。适宜条件下种子一般3d后开始大量萌发,第5d～8d种子萌发陆续进入高峰期,12d后种子萌发速率明显开始下降。春一年蓬更适合在中温(25℃)或稍低温(10℃～15℃)、中性、低盐(≤0.02 mol·L-1)且土壤稍湿润(湿度在30%左右)的环境下萌发生长,种子萌发率大约为70%。(6)春一年蓬花粉萌发最适培养基为:0.5%琼脂+20%蔗糖+15ppm硼酸+10-4 mol·L-1硝酸钙,pH为7,在温度25℃下,花粉萌发率可达50%左右。草甘膦、百草枯和消禾3种不同类型的除草剂对春一年蓬花粉萌发均具有抑制效应,而且都随着药剂浓度的升高萌发率逐渐降低。其中,草甘膦这类内吸型除草剂能够显著抑制花粉萌发,其次是白草枯,消禾的抑制效果最差。当用体积分数为0.2%的草甘膦药剂处理种子时,种子累积萌发率仅在10%左右,而百草枯、消禾除草剂处理后大约为30%。根据以上结果,可以预计春一年蓬会继续向地理和环境条件与目前扩散区相似的地区,如湖北、湖南、山东、江苏、安徽等一带进一步入侵扩散。在机械和化学防除方面,建议在高温无风的天气,喷洒低浓度的草甘膦(0.5%～0.8%)以抑制其产生有活力种子;同时要注意轮换使用作用机制不同的除草剂或同一除草剂品种的不同剂型,从而延缓或阻止入侵杂草抗性的产生;另外,积极开展小麦、水稻、高粱、棉花等重要农作物对入侵杂草的化感抑草作用研究,不仅可以减少对作物栽培对化学除草剂的依赖,还可以保护生态环境和生物多样性,使作物栽培技术向高产、优质、生态、安全生产方向发展;在春一年蓬发生量大的地段,可以通过水旱轮作的方式来控制其危害。更多还原

【Abstract】 Erigeron philadelphicus, a new alien plant of Compositae, has become more and more popular in the suburb of Shanghai by means of the successive survey of the author’s fieldwork from 2005 to 2007. In order to forecast its invasive potentials and ecological risks, the present paper focuses on some invasive biological problems including population and community ecology, stress physiological ecology, reproductive biology, the characteristics of root, chemical prevention, as well as the biological accumulation potential of heavy metal elements of E. philadelphicus. The main results were as follows:(1) The ecological importance values of early spring weeds were surveyed at 261 sites of different habitats in the suburb of Shanghai municipality, a total of 106 weed species were recorded from these sites. The niche breadth and the niche overlaps of 84 main weeds with their frequency over 5% were calculated. Based on their overlaps, the two-dimensional ordination plot of 84 main weeds was drawn using the method of principal axis analysis. Additionally, the ecological similarity of E. philadelphicus with the other main weeds was analyzed according to their niche overlaps. The results showed that,①Galium aparina(0.4419), Solidago canadensi(s0.3413), Ranunculus muricatus(0.3362), Daucus carota(0.2997), Vicia sativa(0.2974), Euphorbia beliocopia(0.2970), Capsella bursa-pastori(s0.2923), Conyza bonarinisi(s0.2780), Veronica persica(0.2556), Humulus scandens(0.2361), Geranium carolinianum(0.2360), Roegneria tsukushiense(0.1997), Rumex japonicu(s0.1906), Alopecurus aequalis(0.1776)have wider niches than Erigeron philadelphicus(0.1768), and Voronica peregrina(0.1669), Sonchus asper(0.1598), Sonchus oleraceus(0.1485), Mazus pumilus(0.1450) and Stellaria uliginosa(0.1393)) have narrower niches.②The first seven exotic weeds having bigger niche overlaps with E. philadelphicus are Sonchus asper(0.501), Rumex japonicus(0.480), Conyza bonarinisis(0.471), Geranium carolinianum(0.356), Rorippa indica(0.347), Alopecurus aequalis(0.327) and Solidago canadensis(0.318).③On the two-dimentional ordination plot resulted from canonical correspondence analysis, we can easily find that E. philadelphicus and the former weeds were most located around the axes of the ordination plots, indicating that they have the similar ecological distribution, often on the dry and open abandoned fields or those disturbed heavily.(2) The concentrations of relative membrane permeability, malonaldehyde (MDA),free proline, soluble sugar, and chlorophyll, as well as the activity of POD of E. philadelphicus under different stresses involving in temperature, water, pH, NaCl concentration were determined in its vegetative growth phase. The results showed: The relative membrane permeability, the content of MDA, free praline, chlorophyll, as well as the activity of POD of E. philadelphicus are highest in 35℃, compared with those at 5℃and 22℃. The relative membrane permeability, the content of MDA,free praline and soluble sugar of E. philadelphicus are highest when treated with pH 10 solution, following by those with pH 4 solution, compared with those treated with PH 7 solution. The relative membrane permeability, the content of MDA, free praline and soluble sugar constantly increased with the rise of NaCl content in soil. Furthermore, the changes of relative membrane permeability and MDA are closely correlated with NaCl concentrations. The decline of soil humidity leads to reduce of the water content in the leaf tissue of E. philadelphicus. The relative membrane permeability, the content of MDA,soluble sugar and free praline increase with the decline of soil humidity. According to the above data, we found:①E. philadelphicus are able to grow better at low temperature of 5℃than at 35℃;②The neutral and moist soils are suitable for E. philadelphicus to grow, either excessive acid or excessive alkali in the soils is harmful to E. philadelphicus;③E. philadelphicus is sensitive to NaCl in soils. E. philadelphicus has somewhat resistance to dry stress.(3) The preliminary allelopathical effects of the aqueous extract or alcohol extract from the aboveground and underground part of Erigeron philadelphicus on the seed germination and seedling growth of Brassica chinensis var. communis, Brassica campestris, Cucumis sativus, Lycoperiscum esculetum were determined. The bioassay indices included seed final germination, root length and seedling height of four. GC-MS was conducted to identify the allelochemicals of the extracts of E. Philadelphicus by soxhlet extraction. We found:①The extracts of E. Philadelphicus could remarkably inhibit the seed’s germination and root length of four receiver crops. Furthermore, such inhibitions were strengthened with the increase of the extract concentration.②Its allelopathical effects on the seedling growth of four receiver crops vary with the extract concentration, stimulating crops to growth at lower concentrations and inhibiting at higher concentrations.③A total of 28 compounds composed of acid, alhocol, aldehyde, keton, ester, and terpene, etc were identified by GC-MS, the main components are acid, keton, ester, and terpene. (4) The contents of five heavy metal elements in E. philadelphicus sampled from different sites in the suburb of Shanghai municipality were measured. We found that different organs have different accumulation abilities to heavy metal elements. Firstly, root has higher absorption abilities to Cu, Cd, and Cr, compared with to Pb and Zn, and their bioaccumulation coefficients are close to 1. The average contents of the five heavy metal elements in E. philadelphicus from high to low followed root, leaf and stem.(5) The seed weight and their germination rates of E. philadelphicus under different environmental conditions were measured. We found that the 1000-seed weight of E. philadelphicus is 0.033±0.003 g, the average water content of seeds is about 70.573±5.871%. Most seeds began to germinate after 3-d culture and its germination rate is about 70% under favor conditions. The seedlings emerge in succession after 5-8d culture. Erigeron philadelphicus grew well under moderate temperature (25℃) or lower temperature (10℃～15℃), netural and slightly moist soil, with low NaCl content (under 0.02mol·L-1).(6) When cultured on the medium with 0.5 agar, 20% sugar, 15ppm H3PO3, 10-4 mol·L-1 Ca(NO3)2 (adjusted to pH 7.0) under 25℃, its pollens germinate rate is about 50%. Test showed that three herbicides including glyphosate, paraquate and xiaohe were able to inhibit the pollen germination rates, such inhibitory effects were strengthened with the increase of the treated concentrations. Glyphosate, an inner-absorption herbicide, was able to inhibit the pollen germination of E. philadelphicus prominently, followed by paraquate and xiaohe. The accumulative germination rate of the seeds treated by 0.2% glyphosate is no more than 10%, while the germination is about 30% if the seeds are treated by paraquate or xiaohe with the same concentrations.Based on the present research, we can peculate that the invasive plant of E. philadelphicus is possible to spread towards other districts with similar climate and geographic characteristics to the present distributing areas, and also to those mid-moist areas,such as Hubei, Hunan, Anhui, Jiangsu, Shandong, Hebei province. On the mechanical and chemical control methods, we suggest that glyphosate of relative low concentrations (0.5%～0.8%) should be sprayed in droughty and windless weather to prevent E. philadelphicus from producing seeds. At the same time, we should use alternately those herbicides having different operation mechanisms or the single herbicides having different dosages, to prevent the invasive plants from producing anti-herbicides property. Additionally, the studies of the allelopathical effects on E. philadelphicus of some important crops, for example, wheat, rice, durra and cotton, are also important, which not only reduces the dependence of herbicides, but also protects our surrounding environments and biodiversities. Finally, to prevent the ecological risk of E. philadelphicus, we should make full use of the way of paddy-dryland rotation in some sites where E. philadelphicus is eugonick.更多还原