遮荫对裸花紫珠苗期光合特性及总黄酮含量的影响

Effect of Shading on Photosynthetic Characteristics and Total Flavonoid Content of Callicarpa nudiflora Seedlings

摘要:

为了解遮荫对裸花紫珠（Callicarpa nudiflora）幼苗生长和药材质量的影响，研究了遮荫处理（遮荫30%、50%、70%和对照0%）下2年生裸花紫珠苗的光合气体交换参数、叶绿素荧光参数、光合色素和总黄酮含量的变化。结果表明，无遮荫或遮荫30%下，裸花紫珠的叶片净光合速率（Pn）日变化曲线呈典型的双峰型，而随遮荫程度的增加，Pn日变化曲线逐渐转变为单峰型。蒸腾速率（Tr）和气孔导度（Gs）日变化曲线呈单峰型，且峰值随着遮荫程度的增加而降低。PSⅡ最大光化学效率（Fv/Fm）和潜在活性（Fv/Fo）的日变化曲线呈“V”型，且两者均随遮荫程度的增加而升高。幼苗叶片的叶绿素a （Chl a）、叶绿素b （Chl b）、类胡萝卜素（Car）含量随遮荫程度的增加而显著增加（P < 0.05），而Chl a/b和Car/Chl却随遮荫程度的增加而下降。随遮荫程度的增加，叶片中总黄酮含量呈先上升后下降的趋势，以遮荫30%为最大。因此，裸花紫珠幼苗最适宜生长在无遮荫条件下，但为获得更高的总黄酮含量，可以选择30%遮荫处理。

Abstract:

In order to understand the effect of shading on growth and quality of Callicarpa nudiflora seedlings, the photosynthetic characteristics, chlorophyll fluorescence parameter, the content of chlorophyll and total flavonoid of two-year-old seedlings were studied under different shading treatments, including shading 30%, 50%, 70% and 0%, respectively. The results showed that the diurnal variation curve of net photosynthetic rate (Pn) of C. nudiflora was bimodal type under 0% and 30% shading, and with the increment of shading, diurnal variation curve of Pn was from bimodal into unimodal type gradually. The transpiration rate (Tr) and stomatal conductance (Gs) were unimodal type, and the peak value also gradually decreased with the increment of shading. The diurnal changes in PSⅡ maximal efficiency (Fv/Fm) and potential efficiency (Fv/Fo) showed ‘V’ type, those average value under shading treatments were significantly higher than those under 0% shading, and significantly increased (P < 0.05) with the increment of shade. The contents of chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid (Car) in the leaves significantly increased with the increment of shading (P < 0.05), but the Chl a/b and Car/Chl decreased with the increment of shading, the content of total flavonoids in the leaves increased at first and then decreased, and reached up to maximum under shade of 30%. Therefore, from the photosynthetic characteristics, C. nudiflora seedling would be suitable for growth under 0% shade, but in order to gain high flavonoids, it would be a good choice under 30% shading.