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[摘要]
目的 以浙江台州、福建闽侯和顺昌3个产地的1年生三叶青Tetrastigma hemsleyanum叶片为实验材料,研究不同光照强度对三叶青植株的蒸腾作用与气孔结构的影响。方法 采用扫描电镜技术观察不同品种三叶青叶片的气孔结构与变化,并测定在不同光照强度 [0~2 000 μmol/(m2·s)] 条件下叶片的蒸腾速率、气孔导度、水分利用率、净光合速率,寻找三叶青栽培中最适光照强度。结果 三叶青的气孔仅存在于叶片下表皮,呈环绕类型平行分布。相同温度下加重了光照强度,浙江台州产地和福建闽侯产地三叶青的净光合速率、气孔导度以及蒸腾速率随着光照强度增加表现出先升高后下降趋势。同时,福建顺昌产地三叶青的净光合速率、气孔导度以及蒸腾速率均显示上升趋势。福建闽侯产地三叶青的光饱和点为600 μmol/(m2·s),顺昌产地三叶青的光饱和点为1 900 μmol/(m2·s),水分利用率保持较高状态。结论 产地和外界光照强度都是影响三叶青蒸腾作用的重要因素,有利于三叶青的块根生长,促进植株体内黄酮类化合物积累。
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[Abstract]
Objective Taking annual Tetrastigma hemsleyanum (Tetrastigma Radix) from three habitats, Taizhou, Minhou,and Shunchang, as materials to study the effects of different light intensity stress on the stomatal shape and leaf transpiration. Methods The stomata, leaf transpiration rate, net photosynthetic rate, and stomal structure of T. hemsleyanum were observed using a scanning [0—2 000 μmol/(m2·s)] to explore the optimal light intensity. Results The stomata with surround and parallel distribution types were only distributed in the lower epidermis in the leaves of T. hemsleyanum; The transpiration rate, stomatal conductance, and net photosynthetic rate of T. hemsleyanum from the two habitat regions (Minhou and Taizhou) by rising after falling with the 30 ℃ stress, which suggested the stress could make the light intensity heavier. At the same time, the transpiration rate, stomatal conductance, and net photosynthetic rate of T. hemsleyanum from the habitat region Shunchang were rising. The stomatal type of leaves was 600 μmol/(m2·s) in Minhou, and 1 900 μmol/(m2·s) in Shunchang, when the water utilization ratio of T. hemsleyanum leaves from the three habitats was higher. Conclusion Different habitats and light intensity are the important factors of leaves transpiration in natural world, which is more beneficial to the growth of the root crops and suitable for the accumulation of flavonoids in plants.
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