Relationship Between Cold Resistance And The Saccharic Metabolism And Antioxidant Activity Of Winter Wheat At Low Temperature

Heilongjiang belongs to the alpine region, the winter temperature is low and continued a long time, the minimum can be up to about-40℃.The stable security overwintering of winter wheat in Heilongjiang has been an important issue of winter wheat breeding.Therefore,the study for physiological and biochemical characteristics along with the low temperature continued of the winter wheat of low temperature treatment is of great significance. In this study, the physiological characteristics of the leaf sheath and the leaf blade in two varieties of winter wheat with different cold resistance as the trial material were tested in the field and the laboratory experiments in order to provide a theoretical basis for winter wheat breeding for cold resistance. The results were as follows:1.Under low temperature treatment, the survival rate of anti-cold varieties Dongnong Dongmai1is higher than cold sensitive varieties Jimai22,a maximum of Dongnong Dongmai1was100%, a maximum of Jimai22was33%.-12℃3d has no effect on the survival rate of the Dongnong Dongmai1,since-18℃1d began its survival rate less than40%,-24℃its survival rate no more than10%. Therefore,-12℃has a great effect on the survival rate of Jimai22, When the temperature is-18℃,its survival rate is zero.2. The relative conductivity of winter wheat increases under low temperature treatment,and trend gradually increased with the processing temperature and processing time increasing. Under the same conditions,the relative conductivity of Dongnong Dongmai1below to Jimai22.3. The production rate of ROS of winter wheat increases under low temperature treatment, and trend gradually increased with the processing temperature and processing time increasing. ROS production rate of cold resistance varieties change in the range of0.2-0.63nmol.g-1FW.min-1, was not cold varieties0.4421-1.241nmol.g-1FW.min-1, under the same conditions, the ROS of Dongnong Dongmai1below to Jimai22. Comparative analysis of hydrogen peroxide(H2O2) draw, under the condition of freezing Dongnong Dongmai1hydrogen peroxide content was significantly lower than that of Jimai22, the hydrogen peroxide content of Dongnong Dongmai1was5.21umol.g-1FW at-12℃3d and5.73μmol.g-1FW at-18℃3d, was Jimai226.62μmol.g-1FW and7.02μmol.g-1FW.4. Change of protective enzyme activity under low temperature treatment performance that the trend of SOD and POD of winter wheat in reviving stage first increased and then decreased, declined slightly in the late cold stress.SOD activity of Dongnong Dongmai1was123.04U.g-1under-18℃3d, was54.77U.g-1in Jimai22, this can well differentiate varieties of cold resistance. The CAT of Dongnong Dongmai1was trend to rise,and the CAT of Jimai22was present a trend of down-up-down, In this study, only in-18℃3d Dongnong Dongmai1CAT activity and Jimai22had significant difference, at this point Dongnong Dongmai1was U.g-1FW.min-1, Jimai22was30.42U.g-1FW.min-1.5. Changes in non-enzymatic oxidation resistant material performance that after cold acclimation of20d, the reduced ascorbic acid(ASA) of Dongnong Dongmai1were significantly higher than that of Jimai22, and the ASA content of Dongnong Dongmai1reached the peak at-12℃3d, reached4564.14μg.g-1FW, while the ASA content of Jimai22in the domestication of Od reached a maximum of1477.59μg.g-1FW, the ASA content of-18℃3d of Dongnong Dongmai1was3935.67μg.g-11FW, while only783μg.g-1FW in Jimai22. The trend of total ASA content and dehydroascorbic acid content with the same trend of reduced ascorbic acid, under low temperature non-enzymatic antioxidants of cold resistance variety to maintain a high content, it can effectively remove active oxygen to maintain a high cold resistance.6. Changes in sugar content under low temperature performance that the soluble sugar content of two varieties of winter wheat crown increased gradually, the highest value appeared in the domestication of30d, at this point the total soluble sugar content of Dongnong Dongmai1and Jimai22crown were255.22and173.95mg-g’1, but the soluble sugar content of Dongnong Dongmai1rise again after the decreased, the total soluble sugar in crown under-18℃3d action rose from182.49mg.g-1to251.48mg.g-1, while its in the Jimai22123.63mg.g-1at-12℃3d down to81.12mg.g-1at-18℃3d, and the soluble sugar content of Dongnong Dongmai1has always been higher than Jimai22. Two varieties of sucrose content in the domestication of30d reached the highest value, sucrose content of crwon higher than that in the leaf, under all low temperature treatment, the sucrose content of Dongnong Dongmai1crown and leaf was significantly higher than that of Jimai22; The fructose content of Dongnong Dongmai1showed a trend of rising, fructose content in crown reached a peak of98.143mg.g-1at-18℃3d, while fructose content of Jimai22crown is only peaked40.793mg.g-1at low temperature acclimation30d, fructose content of Jimai22crown was only19.283mg.g-1. Fructose content in the leaf of two varieties were in the domestication of30d reached the peak, but this time both fructose difference was not significant, fructose content of Dongnong Dongmai1was58.033mg.g-1at-18℃3d, was significantly higher than Jimai of226.063mg.g-1.7. Changes in related enzymes activity of respiratory metabolism under low temperature treatment performance that the PK activity of Jimai22crown was significantly higher than that in Dongnong Dongmai1at cold acclimation phase and-12℃3d, and it was significantly lower than that in Dongnong Dongmai1only at-18℃3d; While under low temperature treatment, HK related respiratory metabolism is shown as the cold resistant varieties was significantly higher than that of non-cold resistant varieties.