夜间复合光质LED不同光照时间对水培切割再生生菜生长和品质的影响

Effect of Different Integrated LED Light Durations in Dark Period on the Growth and Quality of Hydroponic Regeneration Lettuce

以耐切割叶用莴苣品种‘奶油生菜’为试材,用LED光源对越夏水培切割再生生菜进行不同光照时长的夜间补光处理,研究暗期不同的补光时间(0、4、8、12 h)对水培生菜再生植株生长生理及营养品质的影响。结果表明:光照时间的延长,有利于加快生菜再生苗的地上部和地下部的生长速度,使再生生菜的可溶性糖含量显著增加,硝酸盐含量显著降低,有效地缓解高温季节再生苗受到的高温和切割伤害,显著提高了生菜再生苗的产量和品质,并且以延长光照时间为8~12 h效果更佳;其次,随着光照时间延长,再生生菜叶片光合色素的增加,叶绿素荧光主要指标有所提高,提高了叶片光合的同化能力,光抑制现象减弱,其中延长光照时间12h处理叶绿素含量显著或极显著高于其他处理,此外,适当延长光照时间,可增加生菜再生苗对矿质元素N、K、Ca的吸收。在本研究中,补光12 h处理整体最好,但是其产量品质与8 h处理差异不显著,结合生产实际和节能的角度综合考虑,对海南高温季节的水培切割再生生菜进行暗期LED补光,推荐适宜的补光时间为8 h。

In order to ascertain the influence of different integrated LED light durations in dark period on the growth and quality of hydroponic regeneration lettuce, ‘Butter lettuce＇ was taken as the experimental materials, and three treatments（4,8,12 h） prolonging in light durations were carried out. The results showed that the prolonging of light durations was helpful to increase the fresh top-growth of hydroponic regeneration lettuce, significantly increase the content of soluble sugar and significantly decrease the content of nitrite, and it also effectively relieved injury by high temperature and cutting and greatly increased lettuce yield and quality. The prolonging of light durations for 8 and 12 h were better treatments. Secondly, with the prolonging of light duration, photosynthetic pigments and major parameter of chlorophyll fluorescence increased, and the assimilation capacity of the leaf was correspondingly increased, while photo inhibition was relieved in the meantime. Treatment of 12 h prolonging for light duration was significantly or extremely significantly higher than other treatments in chlorophyll content, and sustained relatively higher photosynthetic capacity with better efficiency on light absorption and electron transfer. Besides, appropriately prolonging of light duration accelerated the absorption of mineral elements of nitrogen and calcium, and enhanced its adaptability to high temperature. In conclusion, 12 h were the best treatment, but the yield and quality of the regeneration lettuce for the treatment 12 h and 8 h had no significant difference. Combined with the actual production and energy saving, the treatment of 8 h was the optimal supplementary light time.