【作者】 李月芳；

【导师】 陈欣；

【作者基本信息】 浙江大学 ， 生态学， 2011， 硕士

【摘要】 环境胁迫下的植物间相互作用是近期生态学领域的热点问题,干旱胁迫、高盐胁迫下植物间相互作用有了较深入的研究,但土壤重金属胁迫对植物相互作用的研究较少。本论文以豆科植物鸡眼草为邻体,农作物烟草和玉米为目标植物,研究在重金属单一污染胁迫以及多种重金属交互作用下植物种间的相互作用效应。实验采用不同分隔处理的根箱实验技术进行,研究取得以下主要研究结果：1.无论是重金属复合污染还是单一污染,烟草和玉米的生物量在鸡眼草存在下最低,二者之间存在较大的竞争关系,其中鸡眼草为竞争种。当土壤中有丛枝菌根真菌(AMF)存在时,可使竞争关系减弱。实验结果还显示,二者间地下竞争比地上竞争对植物的影响大。2.烟草和鸡眼草邻体效应实验发现,鸡眼草的存在增加了目标植物烟草的根冠比,从而帮助烟草缓解胁迫所造成的伤害。但玉米在鸡眼草存在下的根冠比与单作相比没有显著差异。3.在重金属复合污染下,鸡眼草和烟草根系之间的离子交流产生的邻体效应指数(RⅡ)为-0.062,对烟草的生长没有促进作用。但是在重金属铅或镉单一污染胁迫下,邻体鸡眼草和玉米根系溶液的交流随着胁迫水平的加深均由竞争关系转变为促进关系。4.在重金属复合污染下,土壤中有AMF的存在下烟草的生物量要高于灭菌处理下的情况。而且鸡眼草与烟草之间的菌丝交流产生的邻体效应指数达0.023,对烟草生长带来微小的促进作用。在重金属单一污染胁迫下,除了铅中度污染除外,其余重金属胁迫水平下邻体植物与玉米根系间菌丝的交流活动对玉米生长有促进作用。5.在铅单一污染胁迫实验中,鸡眼草和玉米的总竞争关系相比于无污染胁迫下显著减弱,而镉污染胁迫下与对照组相比差异不显著。6.实验结果发现,在单一重金属胁迫下,随着胁迫水平的加深,总邻体效应指数的绝对值增加,即竞争关系增强。更多还原

【Abstract】 Interaction among plants under various environmental stresses are the hotspots to ecology. Many studies have focused on plant interactions under drought stress or salt stress, but little is known about plant interactions under heavy metal stress. In this study, we used Kummerowia striata as a neighbour and the crops (maize or tobacco) as target plants to investigate plant interactions under single or combined heavy metal pollution stress. All the expriments are carried out by root compartments in greenhouse. Main results obtained from these experiments are as follows:1. Total plant biomass of tobacco and maize decreased when neighbour plant Kummerowia striata existed both under single or combined heavy metal pollution stress. So plant interactions between tobacco (maize) and K. striata is negative, and K. striata is the competitor. The competition became weaker when AMF existed in the soil. In addition, there was more competition in below-ground than that in above-ground of plants.2. The ratio of root/shoot of tobacco increased significantly when the neighbour plant K. striata existed, indicating that K. striata could alleviate the harmful effects of heavy metal on target plants. However, the ratio of root/shoot of maize did not change significantly with the presence of K. striata.3. The relative interaction index (RⅡ) of tobacco with 0.45μm aperture millipore filtration barrier is-0.062 under the combined heavy mental stress, implying that the exchange of root exudates between plants had inhibitory effects on tobacco growth. But under lead or cadmium heavy mental stress, plant interaction between maize and K. striata with 0.45μm aperture millipore filtration barrier changed from competition to facilitation along with the stress increasing.4. RⅡof tobacco with 25μm aperture millipore filtration barrier is 0.023 under the combined heavy mental stress, implying that hyphe between tobacco and K. striata was beneficial to tobacco growth. Biomass of tobacco is significantly higher in non-sterilized soil than that in sterilized soil, indicating that AMF is the key factor ti the growth of tobacco. The results of maize are in good agreement with that found in tobacco under single heavy mental stress, except for the moderate stress of lead.5. Compared to no heavy mental stress, the competition between maize and K. striata under single pollution stress of lead became weaker. But no significant differences were observed under with and without cadmium pollution stress.6. Absolute value of total RⅡincreased with the increasing stress under single heavy metal stress, implying that competition was enhanced.更多还原