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

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.