GA3和Spd对杜鹃开花期光合特性和抗氧化系统的影响

Effects of GA3 and Spd on Photosynthetic Characteristics and Antioxidant System during Florescence in Rhododendron simsii

摘要:

为探讨GA₃和Spd对杜鹃（Rhododendron simsii）开花花期和开花品质的影响，研究了外源GA₃和Spd对杜鹃开花期光合特性和抗氧化系统的变化。结果表明，外源GA₃对花期有显著的提前作用，Spd对花期有明显的延迟作用，但两者均使花期延长、花径增大且成花率提高。GA₃和Spd处理提高了花期叶片的光合色素含量和净光合速率（Pn）、气孔导度（Gs）和胞间CO₂浓度（Ci）；GA₃处理提高了叶片的蒸腾速率（Tr），而Spd使叶片的Tr下降，两者均有效缓解了末花期叶绿素含量的下降。GA₃和Spd处理显著降低了花瓣MDA含量，提高了抗氧化酶SOD、POD和CAT活性，并减缓了末花期SOD的下降，有效延缓了衰老进程，延长花期。以1 600 mg L^-1 GA₃和0.10 mmol L^-1 Spd处理效果较好，能有效提高杜鹃花的观赏品质。

Abstract:

In order to understand the effects of exogenous GA₃ and Spd on florescence and flowering quality of Rhododendron simsii, the changes in photosynthetic characters and antioxidant system during the flowering period were studied. The results showed that GA₃ had a significant ahead effect on florescence, while Spd delayed. Both of GA₃ and Spd could prolong florescence, increase flower diameter and flowering formation rate. Both of GA₃ and Spd significantly promoted photosynthetic rate (Pn), stomatal conductance (Gs) and intercellular CO₂ concentration (Ci). The transpiration rate (Tr) increased by GA₃, but inhibited by Spd. Both of GA₃ and Spd had relieve effect on decline of chlorophyll content at the end of the flowering. MDA content in petals significantly decreased treated with GA₃ and Spd, and the activities of SOD, POD and CAT increased. At the same time, The decrease of SOD activity in the end flowering stage was slowed down treated with GA₃ and Spd, relieved the ageing process, and extended the flowering. In conclusion, it was better with 1 600 mg L^-1 GA₃ and 0.10 mmol L^-1 Spd, could improve effectively the quality of flowers.