College of Life Science and Agronomy/Henan Key Laboratory of Crop Molecular Breeding and Bioreactor, Zhoukou Normal University, Zhoukou, Henan, 466001, PR China.
College of Life Science and Agronomy/Henan Key Laboratory of Crop Molecular Breeding and Bioreactor, Zhoukou Normal University, Zhoukou, Henan, 466001, PR China.
Plant Physiol Biochem. 2022 Jan 1;170:64-74. doi: 10.1016/j.plaphy.2021.11.040. Epub 2021 Nov 28.
Polyamine (PA), one of the important plant growth regulators, is closely associated with drought stress. However, the function of conjugated PA is not still clear in the roots of cucumber seedlings under polyethylene glycol (PEG) osmotic stress. Therefore, in this study the relationship between the levels of conjugated polyamines and the activity of H-ATPase in plasma membrane was elucidated with the roots of two cucumber (Cucumis sativus L.) cultivars, which were different in drought tolerance, as experimental materials. Furthermore, the contents of free PAs and the activities of S-adenosylmethionine decarboxylase (SAMDC) and transglutaminase (TGase), which were closely related to the levels of conjugated polyamines, were also determined. Results showed that under osmotic stress, the increases of the levels of non-covalently conjugated (non-CC) spermidine (Spd) and spermine (Spm), covalently conjugated (CC) putrescine (Put) and Spd in plasma membrane of drought-tolerant Tangshan 5 were more obvious than those of drought-sensitive Jinyou 1. Furthermore, the conjugated PAs mentioned above were closely correlated with increase rate of seedling dry weight, plasma membrane permeability, water content and H-ATPase activity in plasma membrane. Results of the additional tests, in which exogenous Spd, Spm and two inhibitors, MGBG and phenanthrolin were used, were complementary to the results above. From these results, it could be concluded that non-CC Spd and Spm, CC Put and Spd in plasma membrane functioned in enhancing the tolerance of cucumber seedlings to osmotic stress via elevating H-ATPase activity.
多胺（PA）是一种重要的植物生长调节剂，与干旱胁迫密切相关。然而，在聚乙二醇（PEG）渗透胁迫下，黄瓜幼苗根系中轭合 PA 的功能尚不清楚。因此，本研究以两个抗旱性不同的黄瓜（Cucumis sativus L.）品种的幼苗根系为实验材料，阐明了共轭多胺水平与质膜 H-ATP 酶活性之间的关系。此外，还测定了游离 PAs 的含量、与共轭多胺水平密切相关的 S-腺苷甲硫氨酸脱羧酶（SAMDC）和转谷氨酰胺酶（TGase）的活性。结果表明，在渗透胁迫下，耐干旱的唐山 5 号质膜中非共价结合（非-CC）亚精胺（Spd）和精胺（Spm）、共价结合（CC）腐胺（Put）和 Spd 的含量增加比敏感的津优 1 号更为明显。此外，上述共轭 PAs 与幼苗干重增加率、质膜渗透率、含水量和质膜 H-ATP 酶活性密切相关。用外源 Spd、Spm 和两种抑制剂 MGBG 和菲咯啉进行的附加试验的结果补充了上述结果。从这些结果可以得出结论，质膜中非 CC Spd 和 Spm、CC Put 和 Spd 通过提高 H-ATP 酶活性，在增强黄瓜幼苗对渗透胁迫的耐受性方面发挥作用。
