Search

In order to explore the ability of Australian tea tree tissue culture seedlings to tolerate low temperature and the response mechanism to low temperature stress, this paper determined the 3-month-old Australian tea tree group The process of low temperature treatment of seedlings and the recovery of the leaf chlorophyll (Chl), malondialdehyde (MDA), antioxidant enzymes (SOD, POD, CAT), ascorbic acid Changes in acid (AsA), glutathione (GSH), soluble sugar (SS), soluble protein (SP), and free proline (Pro). The results show that: (1) －5 ℃ stress for 24 hours, the content of protective enzymes and antioxidants decreased significantly, and the content of MDA increased significantly. (2) At 0 ℃, AsA and GSH decreased first and then In contrast to CAT, SOD continued to increase. After 48 hours of stress, the activity of protective enzymes increased significantly, and the content of antioxidants decreased significantly. (3) 10 ℃ The SOD activity first decreased and then increased. After 48 hours of stress, the content of osmotic adjustment substances increased significantly. Therefore, the 3-month-old Australian tea plant tissue culture seedlings were at -5 ℃. Subject to lethal freezing damage, seedlings can respond to low temperature stress above 0 ℃ by activating the antioxidant system and quickly accumulating osmotic adjustment substances. However, there are some differences in the response mechanisms of the two low temperature stresses at 0 ℃. The physiological response mechanism provides a theoretical basis for reasonable introduction and large-scale planting. [ABSTRACT FROM AUTHOR]