| Xiangyan NO.1 and Xiangyan NO. 16 was selected as material in this study to research the effects of 6-BA pretreatment on the photosynthes and biochemical characteristics in pepper seedlings under low temperature and weak light stress (15℃/5℃,100μmol·m-2·s-1).Spraied the pepper seedlings with the 0.08 mmol·L-1 6-BA that selected by preliminary experiment befor 3 days when the pepper seedlings were under low temperature and weak light stress. The pepper seedlings had been spraied by 0.08 mmol·L-16-BA for 3 days.Then determinated the growth index, gas exchange parameters, chlorophyll fluorescence parameters, activities of antioxidant enzymatic, the content of osmotic regulatory metabolites and endogenous hormones of the pepper seedlings under low temperature and weak light. The main results are obtained as follows:The height growth rate, the stalk diametes rate and the fresh weight of the both of pepper cultivars seedlings pretreated by 0.08 mmol·L-16-BA were higher than the pepper seedlings without 6-BA pretreatment under low temperature and weak light.0.08 mmol·L-1 6-BA pretreatment alleviated the decreases of the net photosynthetic rate, stomatal conductance and Troration rate in chilled pepper seedling leaves under weak light. Furthermore, 0.08 mmol·L-16-BA pretreatment decreased the increase of the intercellular CO2 concentration in chilled pepper seedling leaves under weak light. 0.08 mmol·L-1 6-BA pretreatment also raised Fv/Fm,ΦPSⅡ,Fv'/Fm'in the chilled pepper seedling leaves under weak light..At the same time, the 6-BA pretreatment raised the Chlorophyll content in the chilled pepper seedling leaves under weak light.0.08 mmol·L-1 6-BA pretreatment decreased the permeability of cell membrane and increased the malondialdehyde(MDA) production in chilled pepper seedling leaves under weak light. 0.08 mmol·L-1 6-BA pretreatment also enhanced the activities of antioxidant enzymatic including superoxide dismutase(SOD), peroxidase(POD), catalase(CAT) ,ascorbate peroxidase(APX) in the chilled pepper seedling leaves under weak light.0.08 mmol·L-16-BA pretreatment alleviated the increases of the content of proline in chilled pepper seedling leaves under weak light. 0.08 mmol·L-1 6-BA pretreatment also raised the content of soluble protein in the chilled pepper seedling leaves under weak light.0.08 mmol·L-16-BA pretreatment alleviated the increases of the content of ABA in chilled pepper seedling leaves under weak light. 0.08 mmol·L-1 6-BA pretreatment also raised the content of ZR in the chilled pepper seedling leaves under weak light. |
