【作者】 张璐；

【导师】 叶宝兴； 陈欣；

【作者基本信息】 山东农业大学 ， 发育生物学， 2010， 硕士

【摘要】 盐渍化是自然生态系统中一种胁迫生境条件,土壤盐渍化严重制约着农业生产,影响了资源与环境的可持续发展,成为全球亟待修复的土地类型之一。紫花苜蓿（Medicago sativa L.）是重要的豆科牧草,其营养、饲用价值居于各种牧草之首,同时叶片具有排盐机制,具有一定的耐盐性,在沿海滩涂地区广泛分布,是改良盐碱地的理想材料。菌根是自然界广泛存在的一种植物与菌根真菌的共生体。研究结果表明,陆地生态系统中97%的高等植物为菌根营养植物。丛枝菌根真菌（AMF）对作物生长发育、抗逆性、产量和品质等方面的有益作用已在许多研究中得到证实。AMF作为潜在的生物肥料和生物农药,日益成为生态农业研究的热点。前人围绕紫花苜蓿耐盐品种的筛选展开深入细致的研究,以提高紫花苜蓿盐胁迫下的产量,但至于AMF能否提高紫花苜蓿耐盐性鲜见报道,本试验以紫花苜蓿为研究对象,在网室条件下,采用盆栽受控试验的方法,围绕盐胁迫对紫花苜蓿生长的影响及菌根作用进行了系统研究,主要结果如下:1盐胁迫降低AMF的侵染率。本试验研究发现,随盐胁迫程度增加,AMF侵染率有下降的趋势。这与前人研究结果基本一致。2盐胁迫抑制紫花苜蓿的生长。盐胁迫显著减低了紫花苜蓿地上部分和地下部分的个体平均生物量,地下部分总生物量,生长速率,叶面积,冠幅,分枝数,株高和根冠比,显著提高了紫花苜蓿的死亡率。而随盐胁迫程度增加,紫花苜蓿植株体内氮素、磷元素、Mg²⁺、Ca²⁺含量显著下降,脯氨酸、丙二醛、Na⁺含量显著增加,膜透性显著增加。3 AMF促进了紫花苜蓿的营养生长。AMF能显著提高紫花苜蓿地上部分的个体平均生物量、生长速率、叶片数,冠幅半径、分枝数,显著降低重度盐胁迫下紫花苜蓿的死亡率。4 AMF促进紫花苜蓿营养元素和离子的吸收利用。高AMF处理的紫花苜蓿全氮、全磷、Mg²⁺、Ca²⁺含量大于低AMF处理。5 AMF提高紫花苜蓿的耐盐性。高AMF处理的紫花苜蓿脯氨酸、丙二醛、膜透性的含量显著小于低AMF处理。此外,AMF可以降低无盐胁迫和轻度盐胁迫下的地下平均生物量、地下总生物量、根冠比,提高重度盐胁迫下的地下平均生物量、地下总生物量、根冠比,这意味着AMF可以通过调节生物量在地下部分和地上部分的分配来响应外界环境的变化,从而增强紫花苜蓿的耐盐性。更多还原

【Abstract】 Salinized soil is a kind of stressful environment in natural ecosystem. It is urgent to restore salinized soil because salinized soil restricts agricultural production and the lasting development of resources and environment. Medicago sativa L. is a kind of important bird’s-foot with great value for feeding. Also the leaves of M. sativa L. have mechanisms of ejecting salt ions so that M. sativa L. has the ability of salt resistance and exists almost everywhere in tidal land. Arbuscular mycorrhiza is a symbiosis which combines plants with arbuscular mycorrhizal fungi. It has been reported that ninety-seven percent of altitude plants in land ecosystem can form mycorrhizal symbiosis. AMF （arbuscular mycorrhizal fungi） plays an important role in plant growth, stress resistance and yields and quality of crops. More and more studies focus on the role of AMF in agricultural ecology as the fungi can act as latent biological fertilizer and biological pesticide. In order to enhance the yields of M. sativa L under salinized soil, many studies have already focused on the filter of breeds of M. sativa L. with character of salt resistance. However, whether AMF can enhance the salt-resistant ability of M. sativa L. is rarely reported. In our study, we conducted a mesocosm experiment to test the effects of arbuscular mycorrhizal fungi （AMF） on the growth and salinity resistance of M. sativa L. under salt stress. The main results were as follows:1. Salt stress reduced the colonization of AMF. In our study, the colonization rate of AMF decreased with increasing salinity, which corresponded with other studies.2. Salt stress restrained growth of M. sativa L. Salt stress significantly reduced the individual shoot and root biomass, total root biomass, growth rate, leaf area, canopy radius, number of branches, height and root/shoot ratio. Salt stress significantly enhanced mortality of M. sativa L. With salt stress increasing, the nitrogen content, phosphorus content, Mg²⁺ content, Ca²⁺ content decreased while Na+ content, the free proline content, malondialdehyd （MDA） content and membrane permeability in the leaves of M. sativa significantly increased.3. AMF enhanced growth of M. sativa L. AMF significantly increased the individual biomass of shoots, growth rate, number of leaves, canopy radius, number of branches. AMF significantly decreased mortality of M. sativa L. under severe salt stress.4. AMF enhanced the absorption and utilization of elements and ions. The contents of N, P, Mg²⁺, Ca²⁺ of M. sativa L. under higher AMF were higher than those under lower AMF.5. AMF can enhance the stress resistance of M. sativa L. Contents of free proline and malondialdehyd （MDA） and membrane permeability in the leaves were significantly lower under higher AMF than those under lower AMF. Besides, AMF can decrease individual root biomass, total root biomass and root/shoot ratio under no salt stress and slight salt stress while AMF can increase individual root biomass, total root biomass and root/shoot ratio under severe salt stress. So we could conclude that AMF can increase salt resistance of M. sativa L. by modulating the biomass which was distributed according to the change of environment.更多还原