Signal Functions of Nitric Oxide in the Freezing Resistance in the Leaves of Evergreen Woody Plants of Sabina
The seasonal changes of anti-oxidative systems, lipid peroxidation, apparent NO-release, activities of NO synthase (NOS) and nitrate reduc-tase ( NR) in the leaves of Sabina przewalskii (SP) and Sabina chinensis (SC) were investigated to understand the role of endogenous NO, as a signal molecule in freezing tolerance of evergreen woody plants. The results showed that activities of CAT, POD and APX, contents of GSH, Pro and Car increase with temperature decrease, and the maxima appear in the winter. MDA content, the rate of NO release, NOS and NR activity increase markedly and reach two peaks in September and February, respectively. Meanwhile, with mean temperature decreasing from August to January, the correlations between the activities of POD, CAT, APX and contents of GSH, Car and Pro and the mean temperature and MDA content in the both species become negative. Furthermore, NO generation is always found before increasing of anti-oxidative enzyme activity and antioxidant content, indicating that the anti-oxidative systems play an important role in potentiating freezing-resistance of the plant and limiting the production of free radicals to protect membrane integrity. NO as an early signal molecule is able to induce the freezing tolerance by activating the anti-oxidative system involved in both anti-oxidative enzyme and antioxidant. On the other hand, SP shows a prevailing strategy in signal function of NO and has higher anti - oxidative enzyme activity and antioxidant content than SC in order to develop the tolerance to freezing.
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NSTL
万方数据
维普
