摘要： 为探索桑树幼苗对红蓝组合光的响应机制，以LEDs为光源，以桑树幼苗为试验材料，设红光（0B）、蓝光（100% B）和红蓝组合光（15% B、20% B、30% B、50% B）6个处理，以白光为对照，研究不同配比红蓝光对桑树幼苗生长、光合活性、叶绿素含量等方面的影响。结果表明：红光可促进桑树幼苗的茎伸长和叶片展开，但引起桑树幼苗叶片净光合速率（Pn）、光系统Ⅱ光化学活性、碳代谢能力降低；而补充蓝光虽然抑制桑树幼苗茎伸长和叶片展开，却逆转或削弱了这些红光的负面效应，促进叶片比叶质量、Pn、光系统Ⅱ光化学活性和单位面积叶绿素含量升高，叶片Rubisco活性增强。相比于白光、红蓝组合光和蓝光处理，红光下桑树叶片Pn降低可能主要是由于光系统Ⅱ光化学活性、气孔导度（Gs）、叶绿素含量、Rubisco含量和活性降低造成的。总体来看，红蓝组合光下植株的生长状况、生理特征与白光处理相似。由此可知，一定比例的红蓝组合光（15% B和20% B）可减弱单质红光、蓝光对桑树幼苗生长的不利影响。在红光基础上补充蓝光对保持桑树幼苗叶片光系统Ⅱ光化学活性，驱动光合作用至关重要。

关键词: 桑树, 光质, 红光, 蓝光, 生长, 生理特性

Abstract: In order to explore the mechanism of response of growth and development of mulberry seedlings to the combination of red and blue light. The LEDs as light sources were used in this study with 6 treatments including red light (0B),blue light (100%B) and combinations of red and blue light (15%B,20%B,30%B,50%B),white light as control,and the effects of different proportions of red and blue light on the growth,photosynthetic activity and chlorophyll content were studied to provide reference for practical application of red and blue LEDs. The results showed that red light could promote stem elongation and leaf expansion of mulberry seedlings,but caused the decrease of net photosynthetic rate (Pn),photochemical activity of photosystem Ⅱ (PSⅡ) and carbon metabolism related key enzymes activity; although the supplemental blue light (B) inhibited stem elongation and leaf expansion,yet the supplemental blue light reversed or alleviated these negative effects of red light. The supplemental blue light promoted the increase of leaf mass per unit area (LMA),Pn,photochemical activity of PS Ⅱ,chlorophyll content per unit leaf area and Rubisco activity. Compared with white light treatment,combinations of red and blue light treatment and blue light treatment,the decrease of Pn under red light was mainly due to the decrease of photochemical activity of PSⅡ,chlorophyll content,stomatal conductance (Gs),Rubisco content,and Rubisco activity. In general,the growth and physiological characteristics of mulberry plants grown under the combinations of red and blue light were similar to that of plants grown under white light (CK). These results indicated that the certain proportions of red and blue light (15%B and 20%B) could alleviate the adverse effects of monochromatic red and blue LEDs light on growth and development of mulberry seedlings. Adding blue light to red light played important roles in maintaining the photochemical activity of PSⅡ in leaves of mulberry seedlings and driving photosynthesis in leaves of mulberry seedlings.

Key words: Mulberry, Light quality, Red light, Blue light, Growth, Physiological characteristics

中图分类号: 

• :S572.01