Levels of endogenous glycine betaine in the leaves were measured in response to cold acclimation, water stress and exogenous ABA application in Arabidopsis thaliana. The endogenous glycine betaine level in the leaves increased sharply during cold acclimation treatment as plants gained freezing tolerance. When glycine betaine (10 mM) was applied exogenously to the plants as a foliar spray, the freezing tolerance increased from -3.1 to -4.5 degrees C. In addition, when ABA (1 mM) was applied exogenously, the endogenous glycine betaine level and the freezing tolerance in the leaves increased. However, the increase in the leaf glycine betaine level induced by ABA was only about half of that by the cold acclimation treatment. Furthermore, when plants were subjected to water stress (leaf water potential of approximately -1.6 MPa), the endogenous leaf glycine betaine level increased by about 18-fold over that in the control plants. Water stress lead to significant increase in the freezing tolerance, which was slightly less than that induced by the cold acclimation treatment. The results suggest that glycine betaine is involved in the induction of freezing tolerance in response to cold acclimation, ABA, and water stress in Arabidopsis plants.

中文翻译：

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甘氨酸甜菜碱参与拟南芥耐冻性和水分胁迫

测量叶片中内源性甘氨酸甜菜碱的水平，以响应拟南芥中的冷驯化、水分胁迫和外源 ABA 应用。在冷驯化处理期间，随着植物获得抗冻性，叶片中的内源性甘氨酸甜菜碱水平急剧增加。当外源性施用甘氨酸甜菜碱 (10 mM) 作为叶面喷雾时，抗冻性从 -3.1 摄氏度增加到 -4.5 摄氏度。此外，当外源性施用 ABA (1 mM) 时，内源性甘氨酸甜菜碱水平和叶片的抗冻性增加。然而，ABA诱导的叶片甘氨酸甜菜碱水平的增加仅为冷驯化处理的一半左右。此外，当植物受到水分胁迫时（叶水势约为 -1.6 MPa），与对照植物相比，内源性叶片甘氨酸甜菜碱水平增加了约 18 倍。水分胁迫导致耐寒性显着增加，略低于冷驯化处理引起的耐寒性。结果表明，甘氨酸甜菜碱参与了拟南芥植物对冷驯化、ABA 和水分胁迫的抗冻性诱导。