He Jie, Koh Dominic J Q, Qin Lin
Natural Sciences and Science Education Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616; and Corresponding author.
Natural Sciences and Science Education Academic Group, National Institute of Education, Nanyang Technological University, 1 Nanyang Walk, Singapore 637616.
Funct Plant Biol. 2022 May;49(6):483-495. doi: 10.1071/FP20375.
The edible halophyte Mesembryanthemum crystallinum L. was grown at different NaCl salinities under different combined red and blue light-emitting diode (LED) light treatments. High salinity (500 mM NaCl) decreased biomass, leaf growth, and leaf water content. Interactions between LED ratio and salinity were detected for shoot biomass and leaf growth. All plants had F v /F m ratios close to 0.8 in dark-adapted leaves, suggesting that they were all healthy with similar maximal efficiency of PSII photochemistry. However, measured under the actinic light near or above the growth light, the electron transport rate (ETR) and photochemical quenching (qP) of M. crystallinum grown at 100 and 250 mM NaCl were higher than at 500 mM NaCl. Grown under red/blue LED ratios of 0.9, M. crystallinum had higher ETR and qP across all salinities indicating higher light energy utilisation. Crassulacean acid metabolism (CAM) was induced in M. crystallinum grown at 500 mM NaCl. CAM-induced leaves had much higher non-photochemical quenching (NPQ), suggesting that NPQ can be used to estimate CAM induction. M. crystallinum grown at 250 and 500 mM NaCl had higher total chlorophyll and carotenoids contents than at 100 mM NaCl. Proline, total soluble sugar, ascorbic acid, and total phenolic compounds were higher in plants at 250 and 500 mM NaCl compared with those at 100 mM NaCl. An interaction between LED ratio and salinity was detected for proline content. Findings of this study suggest that both salinity and light quality affect productivity, photosynthetic light use efficiency, and proline accumulation of M. crystallinum .
可食用盐生植物冰花（Mesembryanthemum crystallinum L.）在不同的NaCl盐度下，于不同组合的红色和蓝色发光二极管（LED）光照处理下生长。高盐度（500 mM NaCl）降低了生物量、叶片生长和叶片含水量。检测到LED光质比例与盐度之间对地上部生物量和叶片生长存在相互作用。所有植物在暗适应叶片中的F v /F m 比值均接近0.8，这表明它们都健康，且PSII光化学的最大效率相似。然而，在接近或高于生长光照的光化光下测量时，生长在100和250 mM NaCl条件下的冰花的电子传递速率（ETR）和光化学猝灭（qP）高于500 mM NaCl条件下的。在红色/蓝色LED光质比例为0.9的条件下生长，冰花在所有盐度下的ETR和qP均较高，表明光能利用率更高。生长在500 mM NaCl条件下的冰花诱导出了景天酸代谢（CAM）。诱导出CAM的叶片具有更高的非光化学猝灭（NPQ），这表明NPQ可用于估计CAM诱导情况。生长在250和500 mM NaCl条件下的冰花的总叶绿素和类胡萝卜素含量高于100 mM NaCl条件下的。与100 mM NaCl条件下的植株相比，250和500 mM NaCl条件下的植株中脯氨酸、总可溶性糖、抗坏血酸和总酚类化合物含量更高。检测到脯氨酸含量存在LED光质比例与盐度之间的相互作用。本研究结果表明，盐度和光质均会影响冰花的生产力、光合光利用效率和脯氨酸积累。
