水分胁迫下核桃叶片生理生化特性

Physiological and Biochemical Characteristics in Juglans regia L. Leaves under Water Stress

[目的]探讨水分胁迫下核桃离体叶片的生理生化特性。[方法]以2年生核桃树离体叶片为试材,采用室内PEG溶液模拟干旱处理,设置3种PEG6000浓度(质量比分别为3%、9%和15%),以蒸馏水为对照,分别于胁迫61、23、0 h时进行取材,并进行生理生化指标测定。[结果]水分胁迫下,核桃叶水势急剧下降,且PEG浓度在9%条件下下降最明显;叶片相对电导率上升,但各处理差异不明显;叶片SPAD值和Fv/Fm值下降,胁迫至30 h时,其值降至最低;渗透调节物质脯氨酸和可溶性糖上升,其中,脯氨酸含量大量增加;超氧化物歧化酶(SOD)含量先上升后急剧下降。[结论]胁迫条件下,核桃离体叶片的叶水势S、PAD值和Fv/Fm值下降;叶片相对电导率、渗透调节物质脯氨酸和可溶性糖含量及SOD酶活性降低。

[Objective] The study aimed to explore the physiological and biochemical characteristics in Juglans regia L. leaves under water stress. [Method] In the PEG solution-simulated drought treatment in lab, with the vitro leaves of 2-year-old J. regia as tested material and the distilled water as CK, PEG6000 with 3 concn. （mass ratio of 3%, 9% and 15% ）were set up, and the leaves were selected resp. when they were stressed at 6, 12, 30 h and then their physiological and biochemical indexes in stressed laves were determined. [Result] Under water stress, the value of water potential in J. regia leaves was decreased rapidly and this reduction was distinctively obvious when PEG was 9% ; the membrane permeation in leaves was increased and the difference among the treatments was not distinctive; the values of SPAD and Fv/Fm were decreased and they were the lowest under water stress for 30 h; the osmoregulation substance of soluble sugar and proline content were increased, in which the proline content was increased greatly; the uperoxide dismutase （SOD） activity was first increased and then decreased rapidly. [ Conclusion] Under water stress, the water potential in J. regia leaves and values of SPAD and Fv/Fm was decreased and the membrane permeation in leaves, and the osmoregulation substance of soluble sugar and proline content and SOD activity was decreased.