Study On Drought-resistant Of Six Spccies Of Chrysanthemum

This thesis takes six kinds of chrysanthemum which are'Jinbeidahong','Ziyu','Tianxiayipin','Quanxiangchongtian','Junhedewu'and'Guohuahuangzhuan'as its object of study. Culture pot experiment was used to study the changes of physical signs (MDA, relative electricity conductivity, chlorophyll, activity of SOD and POD) and structure characteristics of morphology anatomy of leaves and stem (thickness of leaf, thickness of upper epidermis, thickness of lower epidermis, thickness of palisade tissue, ratio of palisade to sponge tissue, stoma density, length of stoma, thickness of stem epidermal cuticle, length and thickness of epidermal cells) under drought stress. With the aim of having a solid foundation for seed-breeding and research of resistibility of chrysanthemum, the drought resistances of the six kinds of chrysanthemum are analyzed. The main results are shown as following:1. From observing morphology anatomy structure characteristics of leaves of the six kinds of chrysanthemum, we find that the six kinds of chrysanthemum used for experiment have thick leaf which has thick cuticle with waxiness, thick palisade tissue, multiple epidermis, low stoma density indicate strong drought resistance. Thickness of leaf, thickness of palisade tissue, the ratio of thickness of palisade tissue to thickness of sponge tissue and stoma density are the 5 indicators which can be measured obviously as the strength or weakness of chrysanthemum drought resistance whereas the other 4 indicators can not be, according to the analysis of using DPS software to analyze 9 groups parameter of leaf structure in Duncan multi-analysis way. According to analysis the order of drought resistance strength of the six kinds of chrysanthemum used for experiment is:'Jinbeidahong'>'Tianxiayipin'>'Quanxiangchongtian'>'Ziyu'>'Guohuahuangzhuan'>'Junhedewu'.2. The findings of the anatomy structure of stem indicate that: the stem which has thick cuticle in epidermis, many multi-cellular epidermal hairs, tight packaging of epidermis cells shows strong drought resistance. The result gained by using DPS software to analyze the thickness of stem epidermal cuticle, length and thickness of epidermal cells indicates: thickness of epidermal cuticle shows a obvious difference, it can be an indicator to measure drought resistance. According to the result the order of drought resistance strength of the six kinds of chrysanthemum is:'Jinbeidahong'>'Tianxiayipin'>'Quanxiangchongtian'>'Ziyu'>'Guohuahuangzhuan'>'Junhedewu'. It's accordant with the conclusion gained by leaf indicator.3. Under the condition of drought stress, the activity of SOD and POD shows a trend of rise first then fall and rise again as time extension of drought stress; relative electricity conductivity continuously rise; chlorophyll relative content gradually fall; MDA content in'Ziyu'and'Guohuahuangzhuan'continuously rise whereas MDA content in the other 4 kinds of chrysanthemum show a trend of fall first then rise. The orders of chrysanthemum drought resistance are different under different physiological and biochemical characteristics. The order of drought resistance by evaluating these physiological and biochemical characteristics through membership function in vague mathematics:'Jinbeidahong'>'Tianxiayipin'>'Quanxiangchongtian'>'Ziyu'>'Guohuahuangzhuan'>'Junhedewu'.4. Studies have shown that, under a long time of drought stress the six kinds of chrysanthemum which can resist dry conditions through own adjustment ability have a certain skill of degeneration-resistant. The order of strength of drought resistance is:'Jinbeidahong'>'Tianxiayipin'>'Quanxiangchongtian'>'Ziyu'>'Guohuahuangzhuan'>'Junhedewu'.