Studies On Drought Resistance Physiological Adaptability Of 4 Rhizomatous Grasses

Chinese Wild-rye, Smooth Brome, Quackgrass and Kentucky Bluegrass were used as servematerial in experimentation. The method of continue drought was adapted associating pot tests andanalysis in the laborary. The study researched the effects of drought on the physical and chemicalcharacteristics,morphological characteristics of 4 rhizomatous grasses. At last, comprehensiveappraisal of drought resistance of 4 rhizomatous grass were categorized by drought resistance. Themain results were showed as following:1 The growth of plant and spread of leaves were restrained of 4 rhizomatous grasses under waterstress; the relative growth rate showed downtrend. Plants grew more slowly as drought stressaggravated; the length and width of leaves were less than CK; the length and quantity of rootincreased under drought stress.2 The moisture content of leaves of 4 grass declined with the aggravation of drought stress, but thedifference in the species was not significant. There was significant positive correlation between themoisture content of leaves and the moisture content of soil.3 The total content of chlorophyll, chlorophyll a content, chlorophyll b content and chlorophyll a/bratio declined with drought time lasting, and the varietal difference was significant; there wassignificant positive correlation between the total content of chlorophyll, chlorophyll a content,chlorophyll b content, chlorophyll a/b ratio and the moisture content of soil.4 The membrane permeability of leaves increased with the aggravation of drought stress, and thevarietal difference was significant. There was significant negative correlation between themembrane permeability and the moisture content of soil.5 Osmoregulating substance in cells changed significantly. The free praline and the soluble sugarincreased with the decline of the moisture content of soil. There was significant negative correlationbetween the free praline, the soluble sugar and the moisture content of soil.6 The MDA content increased under drought stress; the more MDA content, the longer drought time,and the varietal difference was significant. There was significant negative correlation between thefree praline and the moisture content of soil.7 The POD activity and SOD activity showed the tendency of increasing firstly and thendecreaseing under drought stress. The POD activity and SOD activity were more than the CK duringdrought time. There was no significant relation between the POD activity, SOD activity and moisture content of soil.8 The soluble protein decreased under drought stress, and the varietal difference of protein inabove-ground plant parts was significant, on the other hand, the difference of protein inunder-ground plant parts was not significant. There was significant positive correlation between thesoluble protein and the moisture content of soil.9 According to the research about the drought resistant index of the other people, comprehensiveappraisal of drought resistance of 4 rhizomatous grass were categorized by drought resistance basedon fuzzy mathematics. The elementary result was: Smooth Brome＞Quackgrass＞Chinese Wild-rye＞Kentucky Bluegrass...