| Bermudagrass was a kind of typical warm-season turf grass, in virtue of low stem,slim texture,high-dense,greenish hue,good reproductive capacity,trample-resistance etc, it was generally used to plant turf of park,sports ground,cemetery,airfield,rooting soil and protecting slope and so on. But due to bad cold-resistance, it couldn't been generally utilized in the North of China and cold areas in the world. New varieties "Xinnong No.1 Bermudagrass" and "Kashi Bermudagrass", which were cultivated by the researchers of Xinjiang Agricultural university through ten years' study, besides having traits of the others Bermudagrass, had the most important characteristic, high cold resistance, and could safely live through the winter in Urumuqi,Kelamayi , Xinjiang.Study on the cold-resistant capacity and physiological changes process of Xinnong No.1 Bermudagrass,Kashi Bermudagrass and Tifdwarf under low temperature was made through the physiological and biochemical indexes, which was generally used crop and herbage appraisal. The results were1 winter swamping-snow experiment indicated, under -25.6℃ in Urumuqi, 95 percent Xinnong No.1 Bermudagrass could safely live through the winter, 50 percent Kashi Bermudagrass could do, Tifdwarf couldn't safely live through the winter, as showed Xinnong No.1 Bermudagrass> Kashi Bermudagrass >Tifdwarf on cold-resistant ability.2.the change of plasma membrane was one of physiological indexes that could effectively measure cold-resistant ability of Bermudagrass. Electrolyte effusion rate and curve's pressing or otherwise could suitably reflect difference of the cold-resistance among varieties at the same temperature, and its result was the same as that of winter swamping-snow experiment.3.Under low temperature stress, POD activity emerged the trend of " ahead ascending afterwards descending", and cold-resistant ability might have some positive correlation with POD activity and duration, and POD could be used to measure cold-resistant ability of Bermudagrass.4.In the process of cold-resistance, SOD activity of all Bermudagrass showed the trend of " ahead ascending afterwards descending", but in the process of cold- harm and freeze injury, SOD activity change was different. SOD activity of Tifdwarf was the highest in cold-harm, yet that of Xinnong No.1 Bermudagrass was the highest in freeze injury. Whether SOD activity could be used to appraise cold-resistance of Bermudagrass or not need to be further studied. 5.Pro and soluble sugar accumulation had some correlation with cold-resistant ability of Bermudagrass. But their changes were different in the process of cold- resistance. The more soluble sugar had some correlation with the ability tolerable of low temperature, and emerging early or later of content climax of Pro had some correlation with the cold-resistant ability of Bermudagrass.6.PAGE showed that POD isoenzyme of Xinnong No.1 Bermudagrass was more than that of Kashi Bermudagrass and Tifdwarf, and in the process of cold-harm or freeze injury, no new isoenzyme zone emerges.7.The MDA content had certain positive correlation with over-oxidation degree of cytoplasm membrane .The more MDA content was, the more critical degree of cytoplasm membrane was oxidized, the worse cold-resistant ability of Bermudagrass was.8.Correlation analysis showed, correlation between physiological indexes was different in the process of cold-resistance and freeze-resistance, the results need to be further studied.9.By summarizing all indexes, rhizome could most reflect the cold-resistance difference among varieties of Bermudagrass, and was more cold-resistant than stem and leaf. |
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