Research On Regional Adaptability And Cold-resistance Mechanism Of Varieties (Lines) Of Cynodon Dactylon In Southwest China

In the study,five new Bermudagrass lines and two control Varieties:Nanjing and Tifway were selected for regional adaptability evaluation.Five new excellent Bermudagrass lines have been optimized through comprehensive evaluating 400 Wild Cynodon dactylon which were selected from Southwest of China.On this basis,in order to reveal cold resistance mechanism and impaction of ABA on cold resistance,this study focused on the ABA impaction on Anti-oxidative stress system and Osmotica of Chuannan(Sau9926),Nanjing and Tifway.The main results were as follows:The adaptability of five new bemudagrass varieties were evaluated comprehensively in five regions of southwest China during the period of 2007 to 2008.The introduction variety Tifway and national variety Nanjing were selected as control varieties.The trial sites were located at Yaan,Hongya and Shuangliu in Sichuan,Rongchang in Chongqing and Dushan in Guizhou.Sau9926 has long green period,it is 295d,Nanjing is 283d, Tifway is 277d;Mature time of Sau9926 is about 45d,and faster 1 to 3d than two controls; drought resistance,cold resistance and disease resistance of Sau9926 were better than two controls;density of Sau9926 is about 200/100 cm~2 and more than Nanjing and Tifwway about 20/100 cm~2.Comprehensively analysising texture,color,density,resistance of five new Bermudagrass lines and two control Varieties,overall performance of Sau9926 is best, which is better than two control Varieties.Cold increased electrolyte leakage of both water-treated and ABA-treated Bermudagrass,while RWC decreased under cold conditions.ABA-treated Bermudagrass had lower electrolyte leakage and higher RWC than those of water-treated plant.The results suggested that ABA-enhanced stability of membrane and ABA-decreased Water Stress of cold to bermudagrass.Cold decreased activities of superoxide dismutase(SOD) and catalase(CAT) of both water-treated and ABA-treated bermudagrass,ABA-treated bermudagrass had higher SOD activity and higher CAT activity than those of water-treated plant.ABA could induct to produce SOD and CAT,ABA-enhanced cold resistance of three Bermudagrass was associated with ABA-enhanced activities of SOD and CAT.Soluble sugar,proline and soluble protein content of three Varieties significantly increased under cold.ABA-treated plants had lower soluble sugar and proline content and higher soluble protein content than those of water-treated plants.The results suggested that enhancement in cold resistance by ABA treatment was not correlated to soluble sugar and proline.The accumulation of proline in cold condition was not induced through ABA,but it might be correlated to water stress induced damage on plants.The total chlorophyll content of three Varieties decreased under cold.ABA-treated plants had lower the total chlorophyll content than those of water-treated plants.The results suggested that enhancement in cold resistance by ABA treatment was not correlated to degradate and inhibit synthesis of chlorophyll content.