盐胁迫对珠美海棠幼苗光合特性的影响

为研究盐胁迫对珠美海棠幼苗光合特性的影响,以珠美海棠(Malus zumi)盆栽幼苗为试验材料,测定它们在不同浓度NaCl胁迫下的光合参数和叶绿体色素含量及叶绿素荧光特性的变化。结果表明,盐胁迫下,珠美海棠幼苗的净光合速率(Pn)、气孔导度(Gs)、蒸腾速率(Tr)、PSⅡ的潜在活性(Fv/F0)、PSⅡ实际光化学量子产量、叶绿素b都呈先上升后下降的趋势,胞间CO2浓度(Ci)呈先下降后上升的趋势,叶绿素a和类胡萝卜素均呈下降趋势。低盐浓度(50 mmol·L-1)下,光合相关参数值和叶绿素b含量均有所提高,说明珠美海棠幼苗对盐胁迫有一定适应能力;随着盐浓度升高,珠美海棠幼苗的光合参数、蒸腾速率、叶绿素含量有所降低,表明其光系统受到影响,进而使其光合性能降低。

Effects of Salt Stress on Photosynthesis Characteristics of Malus zumi Seedling

In order to explore the effects of salt stress on photosynthesis characteristics of Malus zumi seedlings, the Malus zumi potted seedlings were used as the experimental materials, and photosynthesis parameters, chlorophyll contents and chlorophyll fluorescence characteristics of the plants were studied under different concentrations of NaC1. The results show that the net photosynthetic rate （Pn）, stomatal conductance （Gs）, transpiration rate （Tr）, potential activity of PS II （Fv/Fo）, the actual photochemical efficiency of PS II and contents of chlorophyll b increased firstly and then declined under salt stress, but intercellular CO2 concentration （Ci） decreased firstly and then increased, and the contents of chlorophyll a and carotenoids decreased continuously. Photosynthesis parameters and contents of chlorophyll b increased under lower salinity （50 mmol·L-1）, which indicated Malus zumi seedlings had a certain resistance to salt stress. The photosynthesis parameters, transpiration rate （Tr）, chlorophyll contents of the plants declined with the salt contents increase, and it indicated that the photosystem of the plant was interfered and its ohotosvnthesis nerformance reduced.