Cd、Pb胁迫对银杏光合特性的影响

Effects of Cd Single and Combined Stress on Chlorophyll Content and Photosynthetic Characteristics of Ginkgo

采用温室盆栽试验方法,研究了Cd、Pb胁迫对银杏光合特性的影响。结果表明:(1)单一Cd和Cd、Pb的复合胁迫均可导致银杏ch la、ch l及叶绿素a/b值的显著下降。银杏ch la和ch l与Cd胁迫浓度表现出显著的负相关。而复合胁迫下,Cd与较高浓度Pb呈现出一定的协同作用。(2)在单一Cd和Cd、Pb的复合胁迫下,银杏的最大光化学效率F v/Fm均明显下降,重金属胁迫使银杏叶片产生了光抑制现象。(3)在重金属胁迫条件下,银杏P n、Gs和T r均随胁迫浓度的增加而下降,而C i则趋于增加。P n随胁迫浓度的提高而下降主要由非气孔限制所致。

Effects of cadmium single and combined stress of cadmium and lead on chlorophyll content and photosynthetic characteristics of Ginkgo were studied in a pot under greenhouse conditions. The main resuits are as follows： （1） The content of chlorophyll （a）, chlorophyll and a/b value gradually decreased by Cd single and combine stress. It was significantly negative correlation between chlorophyll （a）, chlorophyll and the concentration of Cd. The coordinate effect of combined Cd and high concentration Pb was manifested under the combined treatments. （2） The Fv/Fm of Ginkgo obviously decreased by Cd single and combined stress, the phenomenon of photoinhibition of Ginkgo leaf was induced by heavy metal stress. （3） The net photosynthetic rate, stomatal conductance and transpiration rate decreased with the increasing stress concentration, but the intercellular CO2 concentration increased. The decreasing of net photosynthetic rate of Ginkgo under heavy metal stress was caused by nonstomatal limitation.