镉胁迫对山苍子幼苗光合特性变化的影响

Effects of Cadmium Stress on Photosynthetic Characteristics of Litsea cubeba Seedlings

山苍子(Litsea cubeba(Lour.)Pers.)是我国传统中药材,其叶、花、根及果皮均含有精油。山苍子精油具有抑菌效果,镉污染对农田及耕地等土壤生态系统危害极大。为探究镉胁迫对山苍子植株光合生理特性的影响,及山苍子对镉胁迫的耐受度,采用盆栽的方式模拟了镉污染环境。结果表明:镉胁迫对山苍子植株的叶片气孔导度、净光合速率、胞间二氧化碳浓度以及蒸腾速率均存在影响,当胁迫浓度为50 mg/kg,以上各项指标上升胁迫浓度达到100 mg/kg后,各项指标均出现大幅度下降,表明此时已经超过山苍子对镉离子的耐受度。受到镉胁迫后,山苍子植株的光饱和点以及光补偿点均上调,推测是镉离子的毒害作用影响了其光合机能,导致以上指标的上升。

Litsea cubeba was a traditional Chinese herbal medicine in China.Its leaves,flowers,roots and peels all contain essential oil.The essential oil of Litsea cubeba had antibacterial effect.Cadmium pollution was extremely harmful to soil ecosystems such as farmland and cultivated land.In order to explore the effect of cadmium stress on the photosynthetic physiological characteristics of Litsea cubeba plants and the tolerance of Litsea cubeba to cadmium stress,this study used pot culture to simulate cadmium pollution environment.The results showed that the stomatal conductance,net photosynthetic rate,intercellular carbon dioxide concentration and transpiration rate of Litsea cubeba were affected by cadmium stress.When the stress concentration was 50 mg/kg,the above indicators increased.When the stress concentration reached 100 mg/kg,the indicators decreased significantly,indicating that the tolerance of Litsea cubeba to cadmium ions was exceeded.After cadmium stress,light saturation point and light compensation point of Litsea cubeba plants were both increased,suggesting that the toxic effect of cadmium ion affected their photosynthesis,leading to the increase of the above indexes.