Study On Cold Resistance Of Rice Seedlings By Three Inducers Under Low Temperature Stress

In order to solve the problem of cold damage frequently occurred in the process of dry rice cultivation in Heilongjiang province,different plant inducers were investigated in this experiment:Effects of Chito-oligosaccharides,albino-oligosaccharides andγ-aminobutyric acid on cold resistance of rice.Longjing 31,the main cultivar in the third accumulation zone of Heilongjiang Province,was use as the experimental variety.Chito-oligosaccharides,albino-oligosaccharides andγ-aminobutyric acid were select as plant inducers and designed according to the orthogonal test table with three factors and three levels.T1（Chito saccharide 50 mg/L,Albino-oligosaccharide50 mg/L,γ-aminobutyric acid 500 mg/L）,T2（Chito-saccharide 50 mg/L,Albino-oligosaccharide25 mg/L,γ-aminobutyric acid 500 mg/L）were select as the optimal formula.To study the mechanism of cold resistance in rice seedling leaf 2 1 heart of spraying T1 and T2 formula,interval of 2 days to process 1 time,dealt with 3 times,analysis and comparison under the low temperature stress,the plant inducer of rice leaf cold hardiness physiology and the effect of endogenous hormones,and 48 hours after the stress of low temperature normal training process plant inducer of rice leaf cold hardiness physiology and the effect of endogenous hormones.The results are as follows:1.Conventional culture with different inducers could improve seedling quality and increase dry matter accumulation by 15.55%～29.94%.The optimized formula was T1（Chito-oligosaccharide 50 mg/L,Albino-oligosaccharide 50 mg/L,γ-aminobutyric acid 500 mg/L）by orthogonal experiment design.T2（Chito-oligosaccharide 50 mg/L,Albino-oligosaccharide 25mg/L,γ-aminobutyric acid 500 mg/L）.2.At the beginning of low temperature stress,T1 and T2 treatments significantly increased the activities of antioxidant enzymes POD,SOD and CAT in rice leaves,increased the contents of gibberellin（GA）,zeatin（ZR）and indoleacetic acid（IAA）in the order of T1>T2>TCK,and decreased the contents of H2O2 and MDA in plants.The decrease effect of salicylic acid content（SA）was T1>T2>TCK.3.With the prolongation of low temperature stress time（2 d～6 d）,the activities of SOD、POD and CAT in rice seedlings under T1 and T2 treatments increased in the order of T1>T2>TCK,while the contents of H₂O₂ and MDA decreased with the prolongation of low temperature stress time in the order of T1>T2>TCK.SOD activity decreased,H₂O₂ and MDA content increased rapidly.ZR,IAA and GA in rice decreased rapidly at the early stage of low temperature and slowly increased at the late stage of low temperature,while ABA and SA increased rapidly at first and then decreased slowly with the extension of low temperature time.4.After low temperature stress,with the extension of recovery time,the activities of POD,SOD and CAT increased slowly,and the activities of antioxidant enzymes were in the order of T1>T2>TCK on each recovery day,and the contents of H₂O₂and MDA decreased.The endogenous hormones in rice were IAA,GA and ZR increased slowly at first,and abscisic acid decreased rapidly at first and then decreased steadily.