锌胁迫对汉麻光合特性及叶绿素荧光参数的影响

摘要

Objective] The aim was to investigate the effects of zinc stress on photosynthesis and chlorophyll flouorescence characteristics of Cannabis sativa.[ Method] The effects of different concentrations of zinc on the photosynthesis and chlorophyll fluorescence characteristics of C. sativa were studied with a solution culture.[Result] The results showed that with the increase of zinc concentration,the levels of chlorophyll a, chlorophyll b and carotenoids decreased,and the reduction orate of chlorophylla was the fastest compared with 2 μmol zinc treatment(CK).For the plants under zinc stress,net photosynthetic rate (Pn),transpiration rate (Tr) and stomatal conductance (Gs) showed a downward tendency as the concentration of Zn increased,while intercellular CO2 concentration (Ci) increased.During the stress process,(Fv/Fm),actual quantum yield (Y),photochemical quenching coefficient(qP),and electron transport rate (ETR) decreased.The non -photochemical quenching coefficient (NPQ) reached its maximum value at zinc level of 200μmol/L on the 10th day,and then rapidly decay over time.The zinc tolerance of C.sativa was related to the protection mechanism of chlorophyll b and non-photochemical quenching coefficient.[ Conclusion] Zinc had significant effects on photosynthetic mechanism of C.sativa.The process of photosynthesis and metabolism was inhibited and damaged under zinc deficiency and high concentration of zinc.%[目的]研究汉麻在重金属锌胁迫下的光合特性及叶绿素荧光参数的响应。[方法]通过温室水培试验，研究不同浓度锌胁迫对汉麻光合特性及叶绿素荧光参数的影响。[结果]与2μmol／L锌浓度处理（CK）相比，缺锌0μmol／L和高浓度锌处理（50、100、200μmol／L）的汉麻，其叶片的叶绿素a、叶绿素b和类胡萝卜素均下降，叶绿素a减少速率最快；高锌处理随着锌浓度的增加，净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）呈下降趋势，胞间二氧化碳浓度（Ci）缓慢上升。胁迫40 d后，高锌处理的PSⅡ原初光能转化效率（Fv／Fm）、实际光量子产量（Y）、光化学淬灭系数（qP）、光合电子传递速率（ETR）随锌浓度的升高呈下降趋势，非光化学荧光猝灭系数（ NPQ）在200μmol／L锌浓度水平下胁迫10 d后取得最大值，而后随时间延长而迅速衰减，叶绿素b与非光化学荧光猝灭机制对汉麻的光合作用起重要保护作用。[结论]锌对汉麻光合机制有明显的影响，缺锌和高浓度锌对汉麻光合代谢过程有抑制和损害。