光质对番茄和莴苣幼苗生长及叶绿体超微结构的影响

采用发光二极管(LED)精确调制不同光谱能量分布，以荧光灯光照为对照，研究光质对番茄和莴苣幼苗生长及叶绿体超微结构的影响.结果表明：红光下番茄、莴苣幼苗的可溶性糖、淀粉和碳水化合物含量均显著高于对照，叶片叶绿体中淀粉粒膨大显著；蓝光极显著抑制了番茄下胚轴伸长，显著提高了莴苣和番茄幼苗叶片叶绿素a和类胡萝卜素含量；红蓝光下莴苣幼苗叶片的可溶性糖、淀粉、碳水化合物、蔗糖含量和C/N均达到最大值且显著高于红光处理，番茄和莴苣幼苗的主根显著伸长，幼苗叶片中叶绿体形态正常，基粒增多，基质片层清晰，淀粉粒体积明显小于红光处理.光质对植物幼苗的光形态建成、生长、碳氮代谢及叶绿体发育有显著影响；红光下光合产物积累显著但运输受阻严重，在红光中添加适量蓝光更有利于莴苣幼苗的碳水化合物积累，并可促进幼苗根系生长，有利于同化产物输出.

Effects of light quality on the growth and chloroplast ultrastructure of tomato and lettuce seedlings

By using light emitting diode (LED) to accurately modulate spectral energy distribution, and with fluorescent light as the control, this paper studied the effects of light quality on the growth and chloroplast ultrastructure of tomato and lettuce seedlings. Under red LED, the soluble sugar, starch, and carbohydrate contents of tomato and lettuce seedlings were significantly higher than those under fluorescent light, and the starch grains in chloroplast swelled obviously. Under blue LED, the hypocotyl length of tomato seedlings were restrained remarkably, but the leaf chlorophyll a and carotenoid contents of tomato and lettuce seedlings were increased significantly. Under red + blue LED, the soluble sugar, starch, carbohydrate, and sucrose contents and C/N ratio of lettuce seedlings reached the maximal and were significantly higher than those under red LED, the main root length of the seedlings increased significantly, their leaf chloroplast morphology was normal, granum number increased, stroma lamellae was clear, but the starch grain size was smaller than that under red LED. The results suggested that light quality had remarkable effects on the photomorphogenesis, growth, carbon and nitrogen metabolism, and chloroplast development of plant seedlings. Red LED promoted the accumulation of photosynthates but hindered their transport, while adding appropriate amount of blue LED to red LED could more benefit the accumulation of photosynthates in lettuce seedlings, and promote the seedlings root growth and the export of assimilation products.