Effects Of Salicylic Acid On Physiological And Biochemical Character Of Rice Seedlings During Chilling Stress

Chilling stress is a world natural disaster, has become a question to endanger farming production. Rice is an important crop, to be easily affected by low temperature. Along with growing area of rice enlarging and extending in the tropic and subtropical zone to altitude zone, the chilling stress frequency were increased. The temperature of rice seedling growth is instability, even more easily to be chilled. Commonly the daily average temperature is to be stabilized over 12℃, while would affected plant growth if its below 12℃, the time of low temperature lasts over 4 days, would cause rice seed to germinating badness, or seedling growing slowly, dying back, even death.Salicylic acid (SA) belongs to a group of phenolics widely distributed in plants and is now considered an a hormone-like substance ,which plays an important role in the regulation of plant growth and development. In the recent years it has received particular attention to be a signal molecule in acquired resistance to pathogens in several species, its typical function is can be used to induced both the synthesis of certain pathogenesis-related proteins and systemic acquired resistance. Although the focus has been on the role of SA on biotic stresses, recently several studies also supported a major role of SA in modulating the plants response to several abiotic stresses, such as inducing resistance of plants to salt, drought, chilling and heat et al. There has no systemic study on chilling resistance of rice seedling pre-treated with SA. This research studied the effects of morphological, reproductive, physiology and biochemistry of rice seedlings pretreatment with exogenous SA, for researching into the mechanism of chilling resistance, and forming a set for the academic base for SA inducing plants chilling resistance. Provide a reference to the prevention of chilling stress in the beginning spring and improvement the quantity of rice in farming.Rice seedlings were pretreated with 0.5mmol/L SA (spraying or adding to hydroponic solution) under normal growth conditions before were chilled at 6°C, according to the research of physiological-biochemical traits of rice seedling were pre-treated with SA, the following is the main results of the study.1. SA pretreatment could increase chilling resistance of rice seedling by reducing the penetrating of membrane and protecting the stability of membrane system.