The Research Of Mechanism Of Exogenous Hormones In Regulating Winter Wheat Cold Tolerance

Winter wheat is one of the most important crops in our country and it was impacted by low temperature in a large scale, in recent years, it becomes a hot topic of enhancing cold tolerance and reducing the bad impact which was brought by abiotic stresses. The development of study in influence of exogenous hormones on plant supplied the theory basis of exogenous hormones induction technology.Dongnong-1and Jimai22 were taken as materials, and we irrigated the root of seedlings in the period of three-leaf by different concentration of ABA,GA3,6-BA, after the decrease of natural temperature, collect materials in 0℃,-10℃,-25℃and then study the change of physiological indexes, the growth in field and the ratio of greening in the following spring, get the information of impact of exogenous hormones on winter wheat cold tolerance, the main results are following:(1)The influence of ABA,GA3,6-BA on membrane lipid oxidation in winter wheat10-5M ABA increase the activity of SOD in leaves and tillering nodes of Dongnong-1 obviously, decrease the relative electrical conductivity and the content of MDA, while there were no change in Jimai22.However the changes were opposite after the treatment of 10-4M ABA. No change of the activity of SOD and the content of MDA were observed after other concentrations treated. 10-6,10-7M GA3 increased the activity of SOD in leaves and tillering nodes of two kinds of wheats in different degrees, decreased the content of MDA, while they had no impact on the relative electrical conductivity. 10-4,10-5M GA3 decreased the activity of SOD, increased the content of MDA and relative electrical conductivity, the impacts brought by 10-4M GA3 were the most obvious. 10-5M 6-BA increased the activity of SOD in leaves and tillering nodes of these two winter wheats obviously, decreased the relative electrical conductivity and the content of MDA; so did10-7M 6-BA in the leaves and tillering nodes of Jimai22; while there were no impacts almost in these two winter wheats after treated under other concentrations.(2)Influence of ABA,GA3,6-BA on the content of osmosis regulated materials10-5,10-6M ABA increased the content of soluble sugar in leaves and tillering nodes of these two kinds of wheats in different degrees, and the impacts of 10-5M ABA were the most evident, which increased 15.6% and 10.7% more than control, and the content of soluble protein was increased in this concentrate, while no impacts in 10-6,10-7M ABA were observed;10-4M ABA decreased the content of soluble sugar and protein in leaves and tillering nodes of these two winter wheats obviously; 10-7M ABA increased the content of soluble sugar in leaves and tillering nodes of Jimai22;other concentration decreased the content of soluble sugar in different degrees, but no impact on the content of soluble protein.10-6,10-7M GA3 had little impacts on the content of soluble sugars in leaves and tillering nodes of these two wheats, but increased the content of solubility protein; 10-4,10-5MGA3 decreased the soluble sugar and protein in leaves and tillering nodes of these wheats.10-4,10-5,10-6,10-7M 6-BA increased the content of soluble sugar in leaves and tillering nodes of Dongongdongmai-1, and 10-5M 6-BA increased the content of soluble protein also, no impacts on the content of soluble protein in other concentrations were observed; 10-7M 6-BA increased the content of soluble sugar and protein in leaves and tillering nodes of Jimai22, and no impacts were almost observed in other concentrations.(3)The influence of ABA,GA3,6-BA on the content of ingenous hormones10-5,10-6,10-7M ABA treatment increased the ABA content and ABA/GA ratio ,decreased GA content in leaves and nodes of dongnongdongmai 1 , not affect on jimai 22 but only 10-5M ABA decreased the ABA content and ABA/GA in nodes . 10-4M ABA treatment decreased ABA content and ABA/GA in nodes of the tow kinds of wheat , GA content was not change but only increased in leaves of jimai 22.10-5,10-6,10-7M GA3 treatment dongnongdongmai 1 has a lower GA content in leaves and nodes than jimai 22, with higher ABA/GA ratio and ABA content (aba in leaves does not change much ) ; 10-4M GA3 teatment can significant decrease ABA content and ABA/GA ratio but not change the GA content (aba in leaves does not chang much ). Each GA3 treament decreased the GA content in leaves and nodes of jimai 22,increased the ABA/GA, but no afact in ABA content. The row with treatment of 10-4,10-5,10-6,10-7M 6-BA, GA,ABA content and ABA/GA ratio decreased in leaves , ABA and ABA/GA ratio get down but GA goes up ; 10-6M 6-BA treatment increase the ABA content and ABA/GA ratio , but other 6-BA treatment rows cannot saw any impackt, all the treatment decreased the GA content in the leaves and nods of jimai 22 in diferent degrees.(4)The Influence of ABA,GA3,6-BA on seeding habits and greening rateDonongdongmai 1 in the over- winter seeding grows prostrated on the ground , strong green leaves, wheal jimai 22 stands up with light green leaves. There is not much diferencs between rows in diferent treatments of ABA and 6-BA. The dongnongdongmai 1 with the treatment of 10-4M GA3 was much lick jimai 22, but GA3 does not bring such diference in jimai 22.