Effects Of SA On The Physiological Characteristics In Maize Seedling Under Low Temperature Stress

Maize is the world’s largest food crop and a subtropical thermophilic crop. It has such low temperature in spring in Heilongjiang that causes the corn seedling chilling injury and serious production easily. Therefore, it is very necessary to make the research and development on the application of effective plant growth regulating substances to enhance the ability of corn to resist chilling injury. Salicylic acid(SA) is a typical representative of plant hormones which can increase crop yield, improve fruit quality and adversity stress resistance, and has other functions.In this study, Xianyu 335 and parents PH4 CV,PH6WC were taken as test materials, technical means such as plant physiology and biochemistry were used, temperature is set to 17 degrees during the day, at night the temperature is set to 8 degrees, exogenous application of different concentration of salicylic acid treatment on corn seedlings was made, Salicylic acid concentrations were 50 mg/L,100 mg/L and 150 mg/L respectively, analyzed the influence of SA on several aspects about biomass accumulation, photosynthesis, osmotic regulation system, the effects of antioxidant system, to explore how SA enhanced the corn seedling adversity resistacne and open a new direction of crop resistance exercise, especially enhance the physiological activity of corn under low temperature stress, hope to make help for the future researchers. The experimental results showed that:(1)Under low temperature stress, SA treatment improved rate of seedling germination in corn,made the seedling fresh and dry weight higher than control.(2) Under low temperature stress, SA can significantly reduce the low temperature inhibition of chlorophyll synthesis, effectivly control of the change of the fluorescence parameters, increase the corn leaf chlorophyll content, slow down initial fluorescence(Fo) value increase, Fv/Fm, Fv/Fo, NPQ value rise, improve photosynthesis, promote carbon assimilation ability, promote the synthesis of nutrients, increase the corn leaf weight.(3) Under low temperature stress, exogenous SA decreased conductivity and MDA content, reduced the cell membrane permeability, maintained osmotic balance. It improved the soluble sugar and soluble protein content, maintained normal metabolism of the cell activity; SA can enhance the vitality of antioxidant enzyme system, accelerate the metabolism of cells and the normal physiological activities.The concentration of 100 mg/L SA is best to maize seedling against cold resistance.