| In Northeast China,the temperature fluctuates greatly in early spring,and the sowing of spring maize is prone to cold injury.Under the background of climate warming,in recent years,in order to catch up with the advance,852 farm summed up a set of effective "three five sowing method"(that is,5 cm soil temperature can be sown when it exceeds 5 ℃ for 5 consecutive days).Combined with the production practice,three early maturing hybrid maize varieties were selected in this experiment,and six treatments including coated and uncoated treatments were considered.The artificial climate box was used to simulate the low temperature treatment of 4 ℃,5 ℃,6 ℃,7 ℃,room temperature of 19 ℃ as the control.The effects of low temperature stress on seed germination indexes such as germination potential,germination rate,germination index,electrical conductivity,malondialdehyde,proline and soluble sugar content were studied.In order to provide a theoretical basis for the identification of cold tolerance of early sowing maize varieties in spring.The main results are as follows:(1)Low temperature stress has an important effect on the germination index of maize seeds,such as germination potential and germination rate,and the effect of different temperature stress on seed germination is also different.The lower the temperature,the greater the influence on seed germination,the lower the seed vigor and the lower the emergence rate;on the contrary,the higher the temperature,the higher the emergence rate.At room temperature of 19 ℃,the germination rate of the coated seeds of the three varieties can reach the standard level,and the germination rate is not less than 85%.When the low temperature stress was 7 ℃,the germination rates of coated seeds of Demeia 3,Fuyu 1505 and Jinxiu 206 decreased by 50%,51.06% and 54.24% respectively compared with those at 19 ℃,and the germination rates of uncoated seeds decreased by 44.64%,49.59% and 54.76% respectively.The low temperature stress increased from 7 ℃ to 6 ℃,5 ℃ and4 ℃,and the germination potential,germination rate,germination index and vigor index continued to decline.In this process,the maize variety Demeia 3 had better ability to regulate and resist low temperature stress,Fuyu 1505 was resistant to low temperature stress,and Jinxiu 206 had the lowest ability to resist low temperature stress.(2)The physiological process of seeds under low temperature stress is extremely complex,which is composed of multiple indicators interacting with each other,resulting in the difference of low temperature tolerance of different varieties of maize.Different low temperature stress on physiological and biochemical indexes of corn affect different,low temperature,by the size of the relative conductivity,mda content,proline content and soluble sugar content of trends,as well as the combination of seed germination showed a certain physiological indexes of maize seeds cannot ultimately reflect hardy properties,The effect of low temperature stress on maize seed germination can be demonstrated by a variety of physiological and biochemical effects.(3)Under low temperature stress and room temperature,the germination rate of coated seeds of Fuyu 1505 and Jinxiu 206 were higher than that of uncoated seeds.When the temperature was4 ℃,5 ℃,6 ℃,7 ℃ and 19 ℃,the germination rate of Fuyu 1505 coated seeds was 1.19%,1.19%,1.19%,5.95% and 7.42% higher than that of uncoated seeds,respectively.The germination rate of Jinxiu 206 coated seeds was 1.19%,2.38%,2.38% and 1.86% higher than that of uncoated seeds at 5 ℃,6 ℃,7 ℃ and 19 ℃,respectively.However,the germination rate of the coated seeds was lower than that of the uncoated seeds at all low temperatures,which was 3.58%,5.96%,3.57%and 5.36% lower than that of the uncoated seeds at 4 ℃,5 ℃,6 ℃ and 7 ℃,respectively,but coating or not is not the main factor that affects the germination of Demeiya 3. |
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