Effects of low temperature stress on respiration, physiological and biochemical parameters of blueberry branches
In order to clarify the resistance to low temperature of different parts of blueberry branches, the physiological responses of 1-year-old branch tip and base and two-year-old stem of blueberry at low temperature were studied, through the method of artiifcial simulation of low temperature. The results showed that there was a certain correlation between the physiological indexes of different parts of blueberry stems under low temperature stress, but the correlation coefifcients have great difference between different physiological indexes. In other words, different physiological processes of blueberry stems under low temperature stress had signiifcant different sensitivities to low temperature. Among them, at 0℃, respiration rate of 1-year-old branches, especially its branches tip, was signiifcantly higher than that of two-year-old branches. But their respiration was also particularly sensitive to low temperature. When the temperature dropped to-10℃, the respiratory rate was markedly reduced, with greatest reduction in 1-year-old branch tip. In addition, increase amplitudes of malondialdehyde (MDA) content and relative electric conductivity of 1-year-old branch tip increment were signiifcantly higher than those of 1-year-old branch base and 2-year-old branches under low temperature stress, so 1-year-old branch tip was more sensitive to low temperature stress. Different parts of branches under low temperature stress could improve their cold tolerance through increasing soluble sugars (SS) and soluble protein (SP) contents, as well as enhancing activities of antioxidant enzymes (SOD and POD). When temperature dropped to-40℃, low temperature not only inhibited soluble protein synthesis of 1-year-old branch tip, but also SOD activities of 1-year-old branch tip and base were lower than those at-20℃ at different degrees. Namely, at 40℃, the inhibition of protein synthesis and reduction of antioxidant enzyme activity of 1-year-old branch tip might be the main cause of freeze and slightly dry phenomenon on blueberry stems in Daxinganling region of northern China. However, 1-year-old branch base and two-year-old branch of blueberry had stronger cold resistance. In addition to low metabolic activity and non-sensitivity to low temperature, effective accumulation of osmoregulation substance and enhancement of antioxidant enzymes activity played an important role in reducing its membrane lipid peroxidation and electrolyte leakage areas.
NETL
NSTL
万方数据
维普
