Effects of Exogenous Glycine Betaine on the Physiological Characteristics in Medicago sativa Seedlings under Low-temperature Stress北大核心CSCD

In this study,the 'Ganong 5th' alfalfa (Medicago sativa L.) was used as experimental material,and two application methods (leaf application,root application) and six exogenous betaine concentrations (0,10,20,30,40 and 50 mmol·L-1) were used to treat the seedlings of alfalfa. Plant growth and related physiological indexes were measured after 7 days of low temperature (4?) stress,and the physiological mechanism of exogenous betaine to alleviate the low temperature stress of alfalfa was explored. The results showed that exogenous GB alleviated the loss of plant height,root length,leaf dry weight,root dry weight and chlorophyll content,and increase the content of soluble sugar (SS) and free proline (Pro),and reduced the increase in leaf relative membrane permeability and MDA content. Exogenous GB increased antioxidant enzyme activities and non-enzymatic antioxidant content. And also,exogenous GB enhanced the osmotic adjustment capacity of the plant by increasing endogenous GB accumulation and BADH activity. These results indicated that exogenous GB enhanced the resistance of Medicago sativa to low-temperature stress under low temperature adjustment. The membership function analysis indicated that spraying 30 mmol·L-1 GB on the leaves and spraying 40 mmol·L-1 GB on the roots had the best effect on alleviating the low-temperature stress of alfalfa seedlings. © 2019 Ｊｏｕｒｎａｌ ｏｆ Ｒｅｆｒｉｇｅｒａｔｉｏｎ. All rights reserved.