【作者】 张倩；

【导师】 陈欣；

【作者基本信息】 浙江大学 ， 生态学， 2011， 博士

【摘要】 植物相互作用在生态学研究中具有重要地位。植物相互作用的方向(正或负作用)及强度受环境因子的影响,然而,所关注的大部分环境因子是非生物的环境因子,生物因子如丛枝菌根真菌如何影响植物相互作用尚需深入研究。理论上,丛枝菌根真菌能够通过促进植物生长而加剧竞争,但这一生物因子与非生物环境因子的交互作用及其对植物相互作用的影响目前仍不清楚。本文试图回答：(1)丛枝菌根真菌是否通过加剧植物种内竞争而影响植物种群自疏动态、环境胁迫是否影响丛枝菌根真菌这一调节作用?(2)丛枝菌根真菌是否加剧植物邻体干扰效应以及环境胁迫的影响?(3)丛枝菌根真菌与宿主植物间的选择性是如何影响植物种内、种间相互作用的?研究采用野外试验、温室受控试验和整合分析等方法进行,得到以下结果：1丛枝菌根真菌对植物种群自疏过程的影响无盐胁迫条件下,丛枝菌根真菌增大了紫花苜蓿(Medicago saliva L.)植物个体大小,加剧了植物种内竞争,使得自疏线变斜,自疏过程中植物死亡率较高。在盐分胁迫条件下,丛枝菌根同样能够促进紫花苜蓿的生长,但并未增加种内竞争强度,对自疏线斜率的影响并不显著,自疏过程中的死亡率降低,存活植物个体数目较多。2丛枝菌根真菌与邻体效应温室受控实验的结果表明在无盐胁迫处理条件下,丛枝菌根真菌加剧紫花苜蓿同龄个体竞争,随盐胁迫升高,丛枝菌根真菌的效应并不明显。在成体植株对植物幼苗的邻体效应中,多因子整合分析的结果表明,只有在胁迫条件下,丛枝菌根真菌调节正的邻体效应,无胁迫条件下,丛枝菌根真菌的作用不显著。野外去邻体实验的结果表明,在柽柳(Tamarix chinensis Lour.)成体植株对幼苗的邻体效应中,高盐条件下,丛枝菌根真菌增强正的邻体效应,低盐条件下,丛枝菌根真菌加剧负的邻体效应。3丛枝菌根真菌与宿主植物间的选择性及对植物相互作用的影响研究表明丛枝菌根真菌与宿主植物间存在明显偏好性,对于自疏种群,丛枝菌根真菌与宿主植物间的偏好性影响自疏,对于两个植物种共存的群体,这种偏好性明显影响种间竞争。对紫花苜蓿自疏种群来说,G. diaphanum是对其生长促进程度最大的菌根真菌,诱导了最大强度的种内竞争,自疏程度最大。在加拿大一枝黄花(Solidago canadensis L.)和鸡眼草(Kummerowia striata (Thund.) Schindl.)的种间竞争中,G. geosporum对加拿大一枝黄花的生长最有利,而对鸡眼草的生长不利,与鸡眼草相比,加拿大一枝黄花促进G. geosporum的生长,这一菌根真菌.宿主选择性加速了加拿大一枝黄花对鸡眼草的竞争排斥作用。更多还原

【Abstract】 Plant-plant interactions are important process in plant ecology. Direction (positive or negative) and strength of plant interactions are affected by environmental factors. How abiotic factors affect plant interactions has been well documented. However, whether and how biotic factors such as arbuscular mycorrhizal fungi (AMF) affect plant interactions remains elucidation. The present dissertation explored how AMF influence plant interactions and tried to answer the following questions:(1) Do AMF influence plant self-thinning through increasing plant competition? How does abiotic stress affect the role of AMF?(2) Do AMF enhance negative plant neighbor effect? How does abiotic stress affect the role of AMF?(3) What is the role of AMF-host preference in influencing plant intra-specific and inter-specific interactions? Combining field experiment, controlled experiment in greenhouse and meta-analysis, we got the following results:1Effects of AMF on plant self-thinningUnder no salinity treatment, AMF increased plant size of Medicago saliva L. thus increased intra-specific competition, and further changed self-thinning trajectory. AMF induced greater plant mortality during self-thinning. With salinity stress, AMF can also promote growth of Medicago saliva L., but did not influence plant competition and slope of self-thinning line. AMF decreased mortality and increased survival rate during self-thinning under salinity stress conditions.2Effect of AMF on plant neighbor effectControlled experiment in greenhouse showed that AMF increased plant competition between equal-aged individuals of Medicago saliva L. under no salinity treatment. With increasing salinity, mycorrhizal effect was not significant. Multi-factors meta-analysis showed that AMF driven positive effect of established plants on seedling growth under stressed condition, and this effect was not significant when there is no stress. Neighbor removal experiment in field showed that AMF driven the positive neighbor effect of established individuals of Tamarix chinensis Lour, on seedling growth in the high salinity conditions, but enhanced the competitive effect of established Tamarix chinensis hour, individuals on seedling growth.3Effect of AMF-host preference on plant interactionsResults showed that AMF-host preference existed in the preferred host plants and AM fungi in our studies. This preference influenced plant self-thinning in the mono-cultured plant populations, and inter-specific competition in mixture of two plants. For self-thinning populations of Medicago sativa L., the fungus G. diaphanum promotes plant growth most and induces the greatest self-thinning extent. For the inter-specific competition between Solidago canadensis L. and Kummerowia striata (Thund.) Schindl., the mycorrhizal fungus G. geosporum promotes Solidago canadensis L. growth most and not so beneficial to Kummerowia striata (Thund.) Schindl.. Solidago canadensish. promotes G. geosporum growth better than the host plant Kummerowia striata (Thund.) Schindl.. This preference enhanced the competitive exclusion of Solidago canadensis L. on Kummerowia striata (Thund.) Schindl..更多还原