干旱胁迫对不同大豆品种叶片光合及生理特性的影响

采用盆栽试验，研究了干旱胁迫对4个抗旱大豆品种和4个普通大豆品种叶片的光合特性、叶绿素荧光特性和一些生理特性的影响。结果表明，干旱胁迫下R2、R4、R6三个时期大豆叶片的净光合速率（Pn）、气孔导度（Gs）和蒸腾速率（Tr）均呈下降趋势，普通品种相比抗旱品种下降更为显著；在R2期，胞间二氧化碳浓度（Ci）下降较大，普通品种的下降最为显著，表观叶肉导度（AMC）变化极小；在R4期和R6期，Ci下降幅度变小，AMC呈下降趋势，以普通品种的下降最为显著，推测光合能力下降可能与非气孔限制因素有关。干旱胁迫下光合电子传递量子效率（Фpsii）、光化学猝灭（qP）和表观光合量子传递效率（ETR）均降低，非光化学猝灭（NPQ）升高，原初光能转化效率（n／hz）变化不大。干旱胁迫下叶片丙二醛、脯氨酸和可溶性糖含量增加。

Effects of drought stress on leaf photosynthesis and some physiological traits in different soybean cultivars

Variation of photosynthetic characteristics, leaf chlorophyll fluorescence characteristics and some physiological characteristics of four drought - resistant soybean varieties and four ordinary soybean varieties were in- vestigated under drought stress. The results showed that the net photosynthetic rate （ Pn）, stomata] conductance （Gs） and transpiration rate （Tr） of three growth stages were declined under drought stress. The ordinary soybean varieties were more declined than drought - resistant varieties. The intercellular C02 concentration （Ci） , especially of the ordinary soybean varieties decreased significantly at R2 stage. The apparent mesophyll conductance （AMC） had no obvious change at R2. The Ci decreased less than R2 and the AMC decreased at R4 and R6. The ordinary varieties decreased significantly. This suggested that the stomatal limitation might have led to photosynthesis de- cline. The photosynthetic electron transfer quantum efficiency （dp PSII） and photochemical quenching （qP） and apparent photosynthetic quantum transfer efficiency （ETR） decreased and the photochemical quenching （NPQ） in- creased under drought stress. The original light energy transformation efficiency （Fv/Fm） showed no apparent change. The MDA, proline and soluble sugar content increased under drought stress.