叶用莴苣叶片对LED脉冲光的光合响应模型及光能利用

Photosynthetic response model and light energy utilization of lettuce leaves to LED pulse light

为探究LED脉冲光对作物光合特性的影响,探讨在不影响作物正常生长的前提下如何进一步降低能耗,提高照光效率,选用叶用莴苣(Lactuca sative L.)为试验材料,设置5个占空比水平(20%、40%、60%、80%和100%)和14个频率水平(1、2、4、8、16、32、64、128,256、512、1024、2048、4096和8192Hz),共计70个处理,以连续光(占空比100%)为对照,探讨不同形式脉冲光对叶片净光合速率(Pn)的影响,并构建脉冲光占空比和频率与净光合速率之间的响应模型。通过对模型边际效应、交互作用以及光能利用率(LUE)的分析得出:占空比和频率都对Pn增长有促进作用,随着占空比和频率的增加,Pn也随之增加并最终趋于稳定状态直至与连续光处理的Pn无显著差异;占空比越高,叶用莴苣叶片的Pn达到饱和的频率越低;当Pn达到饱和状态时,脉冲光下的LUE要显著高于连续光。综上,占空比20%、频率512Hz为最佳占空比与脉冲光频率组合。该结果可为优化LED植物节能补光灯光源参数设计及研发提供理论支撑。

In order to explore the effects of LED pulse light on crop photosynthetic characteristics,and explore how to further reduce energy consumption and improve lighting efficiency without affecting the normal growth of crops.Lactuca sative L.was selected as experimental material in this research.Five duty ratio levels(20%,40%,60%,80%and100%)and 14frequency levels(1,2,4,8,16,32,64,128,256,512,1024,2048,4096and 8192Hz)were set and a total of 70processes were performed were used to investigate the effects of different forms of pulse light on the net photosynthetic rate(Pn)of leaves with duty ratio of 100%(continuous light)as the control.The response model between duty ratio and frequency of pulse light and net photosynthetic rate was established.Through the analysis of marginal effect interaction and light use efficiency(LUE),it was concluded that both the duty ratio and frequency of pulse light promoted leaf Pn.With the increase of duty ratio and frequency,Pn also increased and finally tended to a stable state until there was no significant difference with the net photosynthetic rate under continuous light treatment.The higher the duty ratio,the lower the frequency of Pn saturation of lettuce leaves.When Pn reaches saturation state,LUE under pulse light is significantly higher than that under continuous light.To sum up,the duty ratio is 20%and the frequency is 512Hz is the optimal combination of duty cycle and pulse light frequency.The study could provide theoretical support for optimizing the design and development of LED plant energy saving supplementary light source parameters.