Green light enhances growth, photosynthetic pigments and CO₂ assimilation efficiency of lettuce as revealed by ‘knock out’ of the 480–560 nm spectral waveband

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• 作者：H. Liu ; Y. Fu ; M. Wang ; H. Liu
• 关键词：Additional key wordsgas exchange ; green light ; leafy vegetable ; light ; response curve ; pigment ; PN/Ci curve ; photosynthesis
• 刊名：Photosynthetica
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：55
• 期：1
• 页码：144-152
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Plant Physiology;
• 出版者：The Institute of Experimental Biology of the Czech Academy of Sciences
• ISSN：1573-9058
• 卷排序：55

文摘

Adding green component to growth light had a profound effect on biomass accumulation in lettuce. However, conflicting views on photosynthetic efficiency of green light, which have been reported, might occur due to nonuniform light sources used in previous studies. In an attempt to reveal plausible mechanisms underlying the differential photosynthetic and developmental responses to green light, we established a new way of light treatment modeled according to the principle of gene “knock out”. Lettuce (Lactuca sativa L. var. youmaicai) was grown under two different light spectra, including a wide spectrum of light-emitting diode (LED) light (CK) and a wide spectrum LED light lacking green (480–560 nm) (LG). Total PPFD was approximately 100 µmol(photon) m−2 s−1 for each light source. As compared to lettuce grown under CK, shoot dry mass, photosynthetic pigment contents, total chlorophyll to carotenoids ratio, absorptance of PPFD, and CO₂ assimilation showed a remarkable decrease under LG, although specific leaf area did not show significant difference. Furthermore, plants grown under LG showed significantly lower stomatal conductance, intercellular CO₂ concentration, and transpiration compared with CK. The plants under CK exhibited significantly higher intrinsic quantum efficiency, respiration rate, saturation irradiance, and obviously lower compensation irradiance. Finally, we showed that the maximum ribulose-1,5-bisphosphate-saturated rate of carboxylation, the maximum rate of electron transport, and rate of triosephosphate utilization were significantly reduced by LG. These results highlighted the influence of green light on photosynthetic responses under the conditions used in this study. Adding green component (480–560 nm) to growth light affected biomass accumulation of lettuce in controllable environments, such as plant factory and Bioregenerative Life Support System.