导　　师： 夏仁学

学科专业： 090201

授予学位： 博士

作　　者： ;

机构地区： 华中农业大学

摘　　要： 丛枝菌根是土壤中的丛枝菌根真菌与寄主植物根系形成的一种互惠共生体，能帮助寄主植物从土壤中吸收更多的水分和矿质元素，从而成为土壤与植物间物质的运输载体，对植物的生长和发育显得尤为重要。柑橘多栽培于丘陵山地，水分是其获得高产优质的主要限制因子之一。在栽培条件下柑橘根系根毛少且短，甚至无，需要依赖丛枝菌根的吸收作用维持其生长，从而对丛枝菌根的依赖性强。本研究从丛枝菌根真菌的角度，探讨其对柑橘抗旱性的作用及其机理，为阐明菌根抗旱提供理论依据；期望从球囊霉属/(Glomus/)中筛选出适合我国柑橘发展的真菌／菌种，为丛枝菌根真菌在柑橘上的应用提供参考。本研究主要内容和结果如下： /(1/)柑橘丛枝菌根真菌菌种抗旱比较研究。以G．mosseae、G．versiforme、G．diaphanum、G．geosporum和G．etunicatum为供试菌种，接种于正常水分或水分胁迫下的枳/(Poncirus trifoliata/(L．/)Raf．/)和红橘/(Citrus tangerine Hort．ex Tanaka/)实生苗上进行盆栽试验，从菌根发育、植株生长、碳水化合物以及抗氧化酶等方面比较上述5种菌种的抗旱效果。结果表明，水分胁迫明显抑制5种菌种对柑橘根系的侵染，但菌根的各部分结构联系更紧密。丛枝菌根真菌对柑橘抗旱性的作用存在种间差异，正常水分和水分胁迫下对枳实生苗高效的菌种分别是G．versiforme和G．mosseae，G．diaphanum是一个很弱的菌种，不具有抗旱潜力；正常水分和水分胁迫下G．mosseae和G．geosporum均对红橘实生苗具有很强的抗旱潜力，G．etunicatum在红橘实生苗上不具备抗旱潜力。 /(2/)丛枝菌根真菌对柑橘水分和渗透调节的影响。以G．mosseae和G．versiforme为供试菌种，接种于不同水分处理的枳或红橘实生苗上进行盆栽试验。结果表明，在20％、16％和12％土壤含水量条件 Arbuscular mycorrhizas are mutualistic symbioses that form between arbuscular mycorrhizal /(AM/) fungi and the roots of host plants. The symbioses are characterized by bi-movement of nutrients where carbon flows to the symbiosis and inorganic nutrients or water move to the plants, thereby becoming a transported carrier between the roots of host plant and soil. Thus, AM symbioses are important for growth and development of host plants. Citrus is one of important fruit species in southern China. Most of citrus trees are cultivated in highland, and water is a restricted factor to acquire high yield and good quality of citrus. Citrus has rare and short root hairs in field and is fairly dependent on AM fungi that are most Glomus species. This study is to evaluate the effect and mechanism of AM fungi on drought resistance of citrus, and to select some effective fungi using the citrus. The main contents and results in the present study are as follows:/(1/) Selection of AM fungi for drought resistance of citrusExperiment was carried out in potted culture and effects of five Glomus species /(Glomus mosseae, G. versiforme, G. diaphanum, G. geosporum and G. etunicatum/) on mycorrhizal development, plant growth, carbohydrate and antioxidant enzymes in two citrus rootstocks species—trifoliate orange /(Poncirus trifoliata /(L./) Raf./) and tangerine /(Citrus tangerine Hort. ex Tanaka/)—under well-watered and water stress conditions were studied. Water stress significantly decreased the mycorrhizal infection of two citrus roots, whereas all structures of arbuscular mycorrhizae were more closely joined under water stress conditions than under well-watered conditions. Different AM fungi showed the difference of inter-species in drought resistance of citrus seedlings. Inoculation with G. versiforme showed the greatest effects in trifoliate orange seedlings under well-watered conditions and inoculated with G. mosseae the greatest effects under water stress conditions. G. diaphanum was a rather weak fungus for the drought resist

关 键 词： 丛枝菌根真菌 柑橘 渗透调节 抗氧化 磷 球囊霉素 抗旱性

领　　域： [农业科学] [农业科学]