| Most of plants can form mycorrhizal structure in the natural condition. Arbuscular mycorrhizae are the most universal type. Arbuscular mycorrhiza is a symbiotic association between plant roots and arbuscular mycorrhizal fungi (AM fungi) in soil. Plants involved in this association are most of the terricolous plants.The fungi related are classified in six genera of order Glomales, they are Glomus, Sclerocystis, Acautospora, Entrophospora, Gigaspora and Scutellospora. The typical character of AM fungi is that they are able to develop branched structures like a tree in cortex cells of host roots, called arbuscules.The importance of AM fungi is their role as a link between plant and soil. They are mediators of nutrient transport from soil to plant and from plant to soil which are crucial components of both plant and soil development and health. It was known that the AM fungi played a key role in nutrient cycling in the ecosystem and promoting plant growth as well as host plant's protection against environmental stress. Due to the positive effects of AM fungi, the studies and utilization of AM biotechnology were being paid enormous attention, and great advance was achieved all over the world. So, it is very important to study AM fungi for improving the crop production and crop quality and for reservation of ecologic balance.Because root system of Citrus grandis Osbeck cv.Shatianyou lacks root hairs, tree of Citrus grandis Osbeck cv.Shatianyou growth highly depends on mycorrhizae. The research and application in mycorrhizal technology will promote the sustainable development of industry of'Citrus grandis Osbeck cv.Shatianyou. For the purpose of application of mycorrhiza biological technology inpomelo (Citrus grandis Osbeck cv.Shatianyou ) production. Micropropagated seedlings and trees on fields of pomelo {Citrus grandis (L.) Osbeck ) as well as two species of AM fungi (Glomus mosseae Gigaspora margarita) were used in experiments. The designed experiments were carried out as follows:Experiment 1. Influence of AM fungi on water ecophysioIogy and growth of micropropagated Citrus grandis Osbeck cv. Shatianyou seedings during accl inatizationRoots of Citrus grandis Osbeck cv.Shatianyou could form arbuscular mycorrhizae with AM fungi, and they could also be infected by various species of AM fungi. Growth of Citrus grandis Osbeck cv.Shatianyou highly depends on infection of AM fungi. Until now, micropropagated technology to produce Citrus grandis Osbeck cv.Shatianyou seedlings had developed quickly. But the culture of Citrus grandis Osbeck cv.Shatianyou seedlings are carried out in sterile condition, which is impossible for AM fungi to infect roots. Consequently, seedlings are usually weak and hard to survive after being bed out. Therefore, to culture Citrus grandis Osbeck cv. Shatianyou mycorrhizal seedling , it's quite important to inoculate with AM fungi to micropropagated seedling of Citrus grandis Osbeck cv.Shatianyou at the right time. This treatment could increase the survival rate of micropropagated seedlings, stimulate the growth of seedling, improve draught-resistant ability, and speed propagation of some Citrus grandis Osbeck cv.Shatianyou.Investigation of the influence of inoculating AM fungi to micropropagated seedlings of Citrus grandis Osbeck cv. Shatianyou during acclimatization was conducted. Some physiological items including growth of AM fungi, relative water content of seedling leaves, photosynthesis, chlorophyll content, ABA content, proline content, seedling growth effect, and upstake of nutrients such as N, P, K under water stress were tested. Experimental results showed that water stress had negative effects on seedlings growth but few influence on infection ability of AM fungi. Mycorrhizal infection rate of AM fungi increase fast during primary phase, slowly during medium phase and finally reached equilibrium. Because micropropagated seedlings of Citrus grandis Osbeck cv.Shatianyou was infected by AM fungi quickly, absorption and accumulation of N, P by root system increased conseq... |
