弱光条件下LED补光灯的频率和占空比对生菜生长的影响

摘要

[目的]研究不同频率和占空比的间歇光对生菜生长及电能转换效率的影响,进一步细化适宜生菜生长的光频率和占空比.[方法]以生菜品种‘香港玻璃’为材料,以LED为光源,在保证日累积光量一致的情况下,通过调节频率、占空比和照光时间,设置1 Hz/50％/24 h(T1),1 Hz/75％/16 h(T2)和10 kHz/75％/16 h(T3)3个间歇光处理,以连续光处理10 kHz/100％/12 h作对照(CK),研究不同频率和占空比的间歇光对生菜生长、品质、叶绿素含量、净光合速率及电能转换效率的影响.[结果]除T1处理外,间歇光可使生菜的株高、茎粗、叶片数、叶面积、地上和地下鲜干质量及生长速率较对照均有所增加.各处理间可溶性蛋白含量无显著差异;T1处理硝酸盐含量最高,其余各处理间差异不显著;间歇光处理的Vc含量均较对照有所提升.低频率、低占空比的间歇光会使生菜叶绿素含量降低并且不利于生菜的光合作用.T2和T3处理的电能转换效率显著高于CK,较CK分别提高了92.50％和82.50％.[结论]考虑能源消耗并兼顾生菜干物质积累和品质,认为实际生产以频率为1 Hz、占空比为75％、照光时间为16h的处理(T2)为好.%[Objective] Effects of frequencies and duty ratios on growth of lettuce and power convention efficiency were studied to obtain the optimal scheme for growth of lettuce.[Method] ‘Xianggangboli'lettuce was planted under LEDs.With the control group of continuous LED light (CK),three treatment groups with frequency,duty ratio and daily light-on hours combinations of 1 Hz/50％/24 h (T1),1 Hz/75％/16 h(T2) and 10 kHz/75％/16 h(T3) were investigated.Daily light integral was the same for all treatments.Effects of different frequencies and duty ratios on the growth,quality,chlorophyll content,net photosynthetic rate of lettuce and energy conversion efficiency were studied.[Result] Height,stem diameter,leaf number,leaf area,fresh weight and dry weight of aerial and root,as well as relative growth rate were increased under intermittent light treatments except T1.There was no significant difference in soluble protein content among all treatments.Nitrate content of T1 was the highest and there was no significant difference among other treatments.Vc content was improved under all treatments compared to CK.Intermittent light at low frequency and duty ratio was less advantageous than continuous light for chlorophyll content and photosynthesis.The power conversion efficiencies of T2 and T3 were significantly higher than those of CK,with the increases of 92.50％ and 82.50％,respectively.[Conclusion] Considering the energy consumption and growth of lettuce,T2 was the most suitable for practical production.