Physiological Effects Of Exogenous Glycinebtaine On Cold Resistance In Banana Seedlings

Banana is one of the most important economic crops in tropical and subtropical area in world. The production of banana plays an important role of agricultural and social development in tropical area of our country. However, banana is apt to suffer low-temperature injury in our country, which has resulted in large economical lose. Betaine is one of osmotic regulation substance in high plants, which has important role in osmatic adjustment. In order to research cold-resistance mechanism of banana and offer theoretical basis on anti-cold cultivation of banana, the physiological effect of exogenous betaine on inducing cold resistance of banana seedlings was studied.In this paper, the physiological effects of differ concentrations of exogenous betaine to inducing the cold resistance of banana seedlings have been studied by experiment design, including randomize block design and L16(43) orthogonal design.The results were as follows:1. After spraying differ concentrations(5.0,7.5,10.0,12.5 mmol·L-1 ) of exogenous betaine on banana seedlings' leaves , the cold resistance ability of banana seedlings was improved in some extend respectively, the optimal concentration was 10.0 mmol·L-1 among the four concentrations.2. Content of soluble protein, soluble sugar, endogenous betaine, activity of superoxide dismutase in banana seedlings' leaves showed a significant correlation with which in banana seedling' roots under cold stress. There were also showed a positive correlation between content of endogenous betaine and activity of betaine aldehyde dehydrogenase in banana seedling' leaves.3. The synthesis and accumulativation of endogenous betaine was induced by exogenous betaine, there was significant positive correlation between content of endogenous betaine in banana seedlings' leaves and content of endogenous betaine in banana seedlings' roots.4. The treatment with exogenous betaine could promote activity of betaine aldehyde dehydrogenase and increase content of endogenous betaine in banana seedlings' leavesunder low temperature stress, and both of them showed a positive correlation.5. When the duration of cold stress for 24 hours, the cold resistance of banana seedlings could be significantly enhanced through spraying 10.0 mmol·L -1 of betaine solution on banana seedlings' leaves before the first day.6. When the duration of cold stress for 36 or 48 hours, the cold resistance of banana seedlings could be significantly enhanced through spraying 10.0 mmol·L-1 of betaine solution on banana seedlings' leaves before the third days.7. When the duration of cold stress for 72 hours, the cold resistance of banana seedlings could be significantly enhanced through spraying 10.0 mmol·L-1 of betaine solution on banana seedlings' leaves before the 5th days.