The Alleviation Of Epibrassinolide On The Inhibition Of Photosynthesis High Temperature On Sessile Ficus

The Ficus concinna var. subsessilis is the small evergreen tree which is distributed in the subtropical China,Subsessilis has the special landscape value, the resistance to low temperature, sality and other characteristics, now it is mainly used as the urban afforestation tree species in Zhejiang Province.In recent years, the frequent phenomenon of high temperatures in the south of China has been seriously affecting the growth of the plants and the seeding cultivation. Nowadays, there is less research on the change of its physiology and biochemistry under the high temperature stress in China. This topic is based on the cultivation of Sessile Ficus in the common, middle and high temperatures in the intelligent incubator, then add the exogenous hormons Brassinosteroid into the experimental groups. According to the different phases of6hours,24hours,72hours and96hours, the intention of this experiment is to measure the Gas exchange parameters and Fluorescence parameters of Sessile Ficus in different time and temperatures. In order to reveal exogenous hormons Brassinosteroid’s effect on the resistance to the high temperature stress and provide evidence for the management and the extended cultivation of Sessile Ficus by studying the exogenous hormons Brassinosteroid’s relieving effect on the photosynthesis of Sessile Ficus. The results of experiment show that:With the moderately high temperature and Br treatment, compared to moderate high temperature in the control group, The Pn of experiment group increased, Gs decreased but increased later, Tr increased and decreased a little, Fv’/Fm’,φ PSⅡ and qP increased. Under the state of extreme temperature, after being dealt with Br, Pn increased, Gs decreased but increased later, Tr decreased, Fv’/Fm’, φ PSⅡ,qP and ETR increased, compared with the extremely high temperature in the control group, After Br treatment, the activity of SOD, POD, CAT is higher than those leaves without Br treatment, especially under the temperature of41.The results show that under the state of Br treatment, the high temperature stress on Sessile Ficus has been alleviated, and after Br treatment, photosynthesis in plants has increased under both average and high temperature conditions, making the accumulation of plant biomass increased, Br can significantly increase the antioxidative capacity in plants, and enhance the initial protective effect of SOD and POD under the high temperature stress, causing the active oxygen is effective removed and protecting the cell membrane structure and function, and alleviating the damage of high temperature on the small-leaved figleaves sessile.