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Drought-resistance Mechanism Of Several Plants In Minqin And Linze Oasis-desert Ecotone

Posted on:2008-08-27Degree:MasterType:Thesis
Country:ChinaCandidate:X Y ShiFull Text:PDF
GTID:2120360215457115Subject:Ecology
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Base on the particularity of oasis-desert ecotone, we choose study sites in Gansu Minqin and Linze oasis-desert ecotone, and study some soil characteristics and drought-resistance of three plants (Nitraria tangutorum, Haloxylon ammodendron and Calligonum mongolicum, BC, SS and SGZ) .The results show that soil water potential of Minqin is heightening gradually from the edge of oasis to desert, and in Linze, the edge of oasis is highest, then decline. Soil pH almost is 8.1~8.6 and alkalescent. Content of soil total nitrogen shows unobvious difference and negative correlation with soil water potential to a certain extent. Content of soil CaCO3 is high and positive correlative with soil water potential. Changes of content of soil organic matter is similar to soil total nitrogen, because soil organic matter is important origin of soil nitrogen. As a whole, soil in ecotone is low fertile, abundant in calcium and water- scanty and have ecumenic traits of soil in arid area.Cumulation of proline is BC>SGZ>SS. Cumulation of proline is positive correlative with soil water potential and relate with sampling season. Cumulation of soluble sugars in SS is better than BC and SGZ, and there is no obvious correlation between cumulation and soil water potential. SOD activities of three plants in August are higher than in May, and its change in SGZ is biggest. In both months, SOD activity is SGZ>BC>SS and positive correlative with soil water potential. POD activity of BC is far higher than of SS, and not detected in SGZ. POD activities of BC and SS are better positive correlative with soil water potential. CAT activity of SGZ is far higher than BC and SS. CAT activity of SGZ in August is higher than in May. The effect of every factor in three plants is different. It shows drought-resistance mechanism of plant is different.Traits of soil in rhizosphere of BC are different from non- rhizosphere. Soil water potential is rarely different, it relates to water lack in entironment. Soil pH in rhizosphere is lower than non- rhizosphere. Content of soil total nitrogen in rhizosphere is higher than non- rhizosphere, but unconspicuously. Content of soil CaCO3 in rhizosphere is mostly lower than non- rhizosphere, it maybe relates to Soil pH. Content of soil organic matter in rhizosphere is lower than non- rhizosphere. Meanwhile, there is relativity between content of soil CaCO3 in rhizosphere of BC and drought-resistance of BC.
Keywords/Search Tags:drought, oasis-desert ecotone, soil water potential, soil pH value, soil total nitrogen, soil organic matter, soil CaCO3, proline, soluble sugars, SOD, POD, CAT
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