Abstract:

To explore the effect of light on the leaf color and physiological changes of Pennisetum setaceum ‘Rubrum’,the natural light was used as a control,and the shading net with 10% transmittance was used to shading the new leaves until the new leaves fully devloped. Then,remove sun-shade net and using natural light for re-lighting treatmetn. And then the dynamic changes of leaf color parameters and related physiological indexes at different development stages were measured. The results showed that the new leaves of Pennisetum setaceum ‘Rubrum’ were green after shading,and the leaf color parameters L and b values were increased significantly,and the value of a decreased significantly. The contents of chlorophyll a and chlorophyll b were increased significantly,while anthocyanin,flavonoid,soluble sugar content and phenylalnine ammonialyase,chalcone isomerase activities were significantly decreased. The polyphenol oxidase and peroxidase activities were not changed significantly. After the re-lighting treatment,the leaf color gradually turned purple,and the leaf color parameter changed opposite to shading treatmetn. The change of physiological indexes was opposite to the decrease or increase after shading. The PPO and POD activities were not significantly changed,either.

Key words: Pennisetum setaceum ‘Rubrum’, Shading, Regaining natural light, Leaf color parameters, Pigment, Enzymatic activity

摘要：

为探寻光照对紫叶狼尾草（Pennisetum setaceum ‘Rubrum’）的叶色及生理变化的影响，以自然光为对照，用透光率为10%的遮阳网对其进行遮光处理，直至新叶成熟完全变绿后，撤去遮阳网用自然光进行复光处理，而后测量各阶段的叶色参数和相关生理指标的动态变化。结果显示，遮光后紫叶狼尾草新叶为绿色，叶色参数L、b值显著增加，a值显著减少；生理指标叶绿素a、叶绿素b含量显著增加，花色素苷、类黄酮、可溶性糖含量和苯丙氨酸解氨酶（phenylalnine ammonialyase，PAL）、查尔酮异构酶（chalcone isomerase，CHI）活性显著减少，PPO多酚氧化酶（polyphenol oxidase，PPO）、过氧化物酶（peroxidase，POD）活性无明显变化。复光处理后，叶色逐渐转紫，叶色参数变化与遮光相反；生理指标变化与遮光后减少或增加的指标呈相反趋势，PPO、POD活性变化不明显。

关键词: 紫叶狼尾草, 遮光, 复光, 叶色参数, 色素, 酶活性