The objective of the study was to investigate the effects of growth-stage specific lighting for the physiological homeostasis of red leaf lettuce (Lactuca sativa L. cv. Red Cos), by measuring the productivity of photosynthesis and primary metabolism. In the experiments, the main photosynthetic photon flux consisted of red (R) and blue (B) light, supplemented with blue, green (G) or UV-A wavelengths. Decrease of fructose, accompanied by significant decrease of stomatal conductance (gs), the ratio of intracellular to ambient CO2 concentration (Ci/Ca), photosynthetic rate (Pr), light adapted actual quantum yield of PSII photochemistry (ΦPSII), biomass formation and significant increase of transpiration rate (Tr) suggest that supplemental UV-A during maturity stage, after supplemental green irradiation during seedling stage (BRG to BRUV) was the least favourable condition for red leaf lettuce. However, constant irradiation with supplemental green (BRG) or supplemental green irradiation after increased blue exposure (B↑R to BRG) resulted in significant increase of Pr, gs, Ci/Ca, and light use efficiency(LUE), and decrease of Tr and Water use efficiency (WUE). Significant increase of leaf area was observed under supplemental green in both seedlings (BR; BRG) and matured plants (B↑R to BRG). Significant increase of specific leaf area was found under supplemental green (BRG) for seedlings and under increased blue (B↑R) for matured plants. Accordingly, the most favourable growth-stage specific lighting spectrum strategy for red leaf lettuce, based on photosynthetic and primary metabolite response, is supplemental green irradiation after increased blue exposure (B↑R to BRG), whereas, the most favourable condition for seedlings is BRG. According to the PCA correlation matrix, associations among the measured data indicate that WUE negatively correlated with gs and Ci/Ca, while LUE positively correlated with gs and Pr. However, weak correlations between ФPSII, LUE and photochemical reflectance index (PRI) suggest that selected light conditions were not optimal for red leaf lettuce.

中文翻译：

---

红叶生菜生长过程中对不同照明策略的光响应。

这项研究的目的是通过测量光合作用和初级代谢的生产力，研究生长阶段特定照明对红叶生菜（Lactuca sativa L. cv。Red Cos）的生理稳态的影响。在实验中，主要的光合作用光子通量由红色（R）和蓝色（B）光组成，并补充了蓝色，绿色（G）或UV-A波长。果糖减少，伴有气孔导度（gs），细胞内与环境CO2浓度之比（Ci / Ca），光合速率（Pr），光适应PSII光化学的实际量子产率（ΦPSII），生物量形成和蒸腾速率（Tr）的显着提高表明在成熟阶段补充UV-A，在苗期补充绿色辐射（BRG到BRUV）后，红叶莴苣的最不利条件是。但是，持续的补充绿色（BRG）辐照或蓝色暴露增加（BRG的B↑R）后的补充绿色辐照会导致Pr，gs，Ci / Ca和光利用效率（LUE）显着增加，并且Tr降低和用水效率（WUE）。在补充绿色下，在幼苗（BR； BRG）和成熟植物（B↑R至BRG）中均观察到叶面积显着增加。在幼苗的补充绿色（BRG）下和成熟植物的蓝色（B↑R）下，发现比叶面积显着增加。因此，基于光合作用和主要代谢产物的响应，红叶生菜最有利的生长阶段特定光照光谱策略，是增加蓝光暴露后的补充绿色辐照（对BRG的B↑R），而对幼苗最有利的条件是BRG。根据PCA相关矩阵，测量数据之间的关联表明WUE与gs和Ci / Ca呈负相关，而LUE与gs和Pr呈正相关。但是，ФPSII，LUE与光化学反射指数（PRI）之间的相关性较弱，表明所选的光照条件并非对于红叶生菜而言是最佳的。