Effects Of Seed Soaking With Hydrogen Peroxide On The Growth And Chilling Resistance Of Direct-seeding Oilrape

Rape is the only winter oilseed crops in China,the largest producing areas are mainly distributed in the Yangtze River basin.With the development of technology in the area of cultivation,seeding rape has become more and more popular with farmers.But,seeding rape was easily effected by low temperture.It could bring seed vigour decline and make seedling infirmly,so that it effect plant growth and decelopment.The trial studied the effects of seed soaking with H₂O₂ On oilrape?B.napus var Nannongyou 4 and Zhongshuang 11?seedling growth,chilling resistance and the final yield.The action mechanism on oilrape soaking seed with H₂O₂ was studyed and it could offer theoretics basis for oilrape seeding directly.The main results were as follows:1.H₂O₂ soaking could improve the rape seedling growth under low temperature stress,reduce the content of MDA and production of ROS,increase plant dry weight significantly.H₂O₂ soaking could also promote the activities of superoxide dismutase?SOD?and peroxidase?POD?,catalase?CAT?,ascorbate peroxidase?APX?,glutathione peroxidase?GPX?and contents of antioxidants such as ascorbic acid?ASA?and glutathione?GSH?,increase contents of proline,free amino acid,and soluble sugar.The study suggested that soaking seed with H₂O₂ could improve cold tolerance of rape seedling by promoting the ability of antioxidant system and osmotic adjustment so as to promote the seedling growth and seed yield of rapeseed.2.When rapeseed under the low temperature stress,the photosynthesis ability reduced,the chlorophyll contents decreased,the activity of the enzymes involved in the content of soluble sugar and sucrose metabolism increased.Soaking seeds with H₂O₂ could effectively relieve growth inhibitory on different rape varieties under low temperature stress,reduce the content of chlorophyll drop speed,increase the photosynthetic rate,stomatal conductance and other related parameters of photosynthesis of leaves under low temperature stress,further enhanced the soluble sugars and sucrose metabolism related enzymes?such as SPS,SS,INV etc.?activity,thereby enhancing plant cold tolerance.3.H₂O₂ soaking can ease of two rapeseed varieties growth inhibitory effect under low temperature stress,the SOD?POD?CAT and AsA-GSH cycle related protective enzymes activity and antioxidants ascorbic acid?ASA?and glutathione?GSH?content increased significantly,reduce the MDA content and O2-· radical generation rate,the rape seedling height.The study showed that low concentration H₂O₂ soaking can promote antioxidant enzymes in rape and non enzyme production,reduce the content of lipid peroxide,to improve cold resistance of cold of rape.