%A WU Neng-Biao,HONG Hong %T Regulation Mechanism of Intracellular IP3-Ca2+ on Photosynthesis in Maize Seedlings under UV-B Stress %0 Journal Article %D 2013 %J Acta Agronomica Sinica %R 10.3724/SP.J.1006.2013.00373 %P 373-379 %V 39 %N 02 %U {https://zwxb.chinacrops.org/CN/abstract/article_5299.shtml} %8 2013-02-12 %X

UV-B radiation is one of the main adverse environmental factors, obviously affecting plants’ growth and development. Calciumion, as the second messenger in cell signal transduction system, mediates a series of physiological and biochemical reactions, which is helpful to alleviate the damage from adverse environmental factors. To investigate the regulational relation between calcium signal system and UV-B radiation in maize, we studied the effects of calcium signal on photosynthesis in maize (Zea mays L.) seedlings under UV-B stress.With the treatments of seedlings growing in natural condition (CK), 0.15 Wm-2 UV-B radiation (UV-B), 0.15 Wm-2 UV-B radiation+Heparin (UV-B+H), 0.15 Wm-2 UV-B radiation+Trifluoperzine (UV-B+TFP), 0.15 Wm-2 UV-B radiation+LaCl3 (UV-B+LaCl3), 0.15 Wm-2 UV-B radiation+CaCl2 (UV-B+CaCl2), respectively. The Ca2+ fluorescence intensity increased rapidly when it was treated with UV-B. However, when the maize leaves were treated with Heparin (intracellular IP3 channel blocker) and Trifluoperazine (intracellular CaM activity inhibitor), the increase of Ca2+ fluorescence intensity was inhibited in the mean time, chlorophyll contents, Hill reaction activity, water use efficiency (WUE), efficiency of primary conversion of light energy (Fv/Fm) of PSII, and the potential activity of PSII (Fv/Fo) decreased significantly, which finally leads to the decrease of net photosynthetic rate(Pn). However, LaCl3 (plasma membrane calcium channel blocker) had less effect on it. Therefore, we speculate that under UV-B stress, intercellular IP3/Ca2+ system may participate in the process of photosynthetic pigments synthesis, water utilization and Hill reaction activity. CaM downstream reaction can regulate Gs, which is considerd as the main mechanism that Ca2+ signal system eventually achieves the regulation of Pn.