光质对苦瓜幼苗形态建成及碳氮代谢的影响

秦永梅 韩凤英 杨慧 刘敏

摘    要：为探究培育苦瓜壮苗的最适光源，设置红光（R）、蓝光（B）、红蓝光（R1B2）、红蓝光（R2B1）4个处理，以白光（W）为对照，研究不同光质照射对苦瓜幼苗形态建成、光合特性、碳氮代谢的影响。结果表明，与W相比，R促进苦瓜幼苗高度的增加，抑制茎的横向加粗，B的作用与之相反;R2B1的总叶面积、全株干质量、壮苗指数、净光合速率和水分利用效率最大，B的蒸腾速率和气孔导度值最大，水分利用效率最低，R的净光合速率值最低，胞间CO2浓度最高。与W相比，R2B1的总糖、淀粉含量最大，RUBPcase、SPS、SS活性最高，W的蔗糖含量最高。B的叶片全氮、游离氨基酸、可溶性蛋白含量最高，较对照分别增加27.88%、37.92%、30.54%，R1B2次之，但GS和GOGAT活性以R1B2最高，NR活性以R2B1最高。另外，在红蓝组合光中，增加红光比例可以促进苦瓜幼苗叶片碳代谢的加强，而增加蓝光比例可以促进苦瓜幼苗叶片氮代谢的加强。综上所述，R2B1处理的苦瓜幼苗最符合壮苗标准，且净光合速率最大、水分利用率最高、碳代谢最强且氮代谢水平较高。

关键词：苦瓜;光质;形态建成;光合特性;碳代谢;氮代谢

中图分类号：S642.5 文献标志码：A 文章编号：1673-2871（2020）07-024-04

Abstract： In order to explore the best light source for cultivating strong seedlings of bitter gourd， four treatments of red light （R）， blue light （B）， red blue light （R1B2） and red blue light （R2B1） were set up. White light （W） was used as tcontrol to study the effects of different light quality on the morphogenesis， photosynthetic characteristics， carbon and nitrogen metabolism of bitter gourd seedlings. The results showed that compared with W， R promoted the height of bitter gourd seedling and inhibited the transverse thickening of stem， while B had the opposite effect;R2B1 had the largest total leaf area， dry weight of whole plant， strong seedling index， net photosynthetic rate and water use efficiency， B had the largest transpiration rate and stomatal conductance， and the lowest water use efficiency. R had the lowest net photosynthetic rate and the highest intercellular CO2 concentration. Compared with W， R2B1 had the highest content of total sugar and starch， RuBPcase， SPS and SS， and W had the highest content of sucrose. The content of total nitrogen， free amino acid and soluble protein in leaves of B increased by 27.88%， 37.92% and 30.54% respectively， followed by R1B2， but the activities of GS and GOGAT were the highest in R1B2， and the activities of NR was the highest in R2B1. In addition， in the red blue light combination， increasing the red light ratio can enhance the carbon metabolism of balsam pear seedling leaves， while increasing the blue light ratio can enhance the nitrogen metabolism of balsam pear seedling leaves. In a word， R2B1 is the best treatment for bitter gourd seedlings， with the highest net photosynthetic rate， water use efficiency， carbon metabolism and nitrogen metabolism.

Key words：Bitter gourd; Light quality; Morphogenesis; Photosynthetic characteristics; Carbon metabolism; Nitrogen metabolis

光不僅是植物获取能量的直接来源，还是影响植物生长和产物积累的重要调控因子[1]，尤其是波长380～760 nm的可见光被植物机体吸收后，可产生一系列化学反应，进而影响植株的形态建成和各种生理代谢活动等。研究表明，从种子萌发到包括茎叶生长在内的营养形态学、节律运动、向地性、向光性、光合作用、物质代谢和基因表达等均受光信号的调控[2]。……