Photosynthetic characteristics and response of antioxidant to cold adaptation of alfalfa
[Objective]In order to study the changes of photosynthetic characteristics and the contents of antioxi-dant substances of alfalfa during cold adaptation.[Method]The 4-week-old seedlings of 10 alfalfa varieties were cold-adapted at 4 ℃,and their chlorophyll content,osmotic pressure,relative electric conductivity,photosynthetic characteristics,the contents of reactive oxygen species and antioxidant substances were measured on the 0 th,7 th,and 14th days,respectively.[Result]The results showed that in the early stage of cold adaptation (0～7 d),the cell membrane was damaged,resulting in ion leakage and increased the relative conductivity of leaves.As the cold adapta-tion process continues (7～14 d),the amount of ion leakage decreased,the relative conductivity decreased,and the cold resistance of alfalfa was initially formed. Cold adaptation decreased the contents of chlorophyll a and chlorophyll b,net photosynthetic rate,actual photochemical efficiency of PS Ⅱ,and maximum photochemical efficiency of PS Ⅱ in alfalfa.[Conclusion]The contents of osmotic pressure,ascorbic acid,oxidized glutathione and reduced glutathione of alfalfa seedlings increased continuously during cold adaptation.The osmotic pressure and concentration of cell fluid were increased to enhance the osmotic regulation ability of cells. At the same time,the content of antioxidant sub-stances increased and the antioxidant capacity enhanced,which could reduce the content of superoxide anion free radi-cal and hydrogen peroxide.
alfalfacold adaptationrelative electric conductivityphotosynthetic characteristicsantioxidant substances
万方数据
维普
