Miao Yanxiu, Gao Xingxing, Li Bin, Wang Wenjiao, Bai Longqiang
College of Horticulture, Shanxi Agricultural University, Jinzhong, China.
Collaborative Innovation Center for Improving Quality and Increase profits of Protected Vegetables in Shanxi, Shanxi Agricultural University, Jinzhong, China.
Front Plant Sci. 2023 Jan 6;13:1053780. doi: 10.3389/fpls.2022.1053780. eCollection 2022.
Soil salinity severely inhibits leaf photosynthesis and limits agricultural production. Red to far-red light ratio (R/FR) affects leaf photosynthesis under salt stress, however, its regulation mechanism is still largely unknown. This study investigated the effects of different R/FR on plant growth, gas exchange parameters, photosynthetic electron transport, Calvin cycle and key gene expression under salt stress. Cucumber seedlings were exposed to four treatments including 0 mM NaCl and R/FR=7 (L7, control), 0 mM NaCl and R/FR=0.7 (L0.7), 80 mM NaCl and R/FR=7 (H7) and 80 mM NaCl and R/FR=0.7 (H0.7) for 9 days in an artificial climate chamber. The results showed that compared to L7 treatment, H7 treatment significantly reduced relative growth rate (RGR), CO assimilation rate ( ), maximum photochemical efficiency PSII ( / ), most JIP-test parameters and total Rubisco activity, indicating that salt stress severely inhibited photosynthetic electron transport from PSII to PSI and blocked Calvin cycle in cucumber leaves. However, these suppressions were effectively alleviated by low R/FR addition (H0.7 treatment). Compared to H7 treatment, H0.7 treatment significantly increased RGR and by 209.09% and 7.59%, respectively, enhanced / , maximum quantum yield for primary photochemistry ( ), quantum yield for electron transport ( ) and total Rubisco activity by 192.31%, 17.6%, 36.84% and 37.08%, respectively, and largely up-regulated expressions of most key genes involved in electron transport and Calvin cycle. In conclusion, low R/FR effectively alleviated the negative effects of salt stress on leaf photosynthesis by accelerating photosynthetic electron transport from PSII to PQ pool and promoting Calvin cycle in cucumber plants. It provides a novel environmentally friendly light-quality regulation technology for high efficiency salt-resistant vegetable production.
土壤盐分严重抑制叶片光合作用并限制农业生产。红光与远红光比例（R/FR）在盐胁迫下会影响叶片光合作用，然而其调控机制仍 largely 未知。本研究调查了不同 R/FR 对盐胁迫下植物生长、气体交换参数、光合电子传递、卡尔文循环及关键基因表达的影响。黄瓜幼苗在人工气候箱中接受四种处理，包括 0 mM NaCl 且 R/FR = 7（L7，对照）、0 mM NaCl 且 R/FR = 0.7（L0.7）、80 mM NaCl 且 R/FR = 7（H7）以及 80 mM NaCl 且 R/FR = 0.7（H0.7），处理 9 天。结果表明，与 L7 处理相比，H7 处理显著降低了相对生长速率（RGR）、CO₂同化速率（ ）、最大光化学效率 PSII（ / ）、大多数 JIP 测试参数以及总 Rubisco 活性，表明盐胁迫严重抑制了黄瓜叶片中从 PSII 到 PSI 的光合电子传递并阻断了卡尔文循环。然而，低 R/FR 添加（H0.7 处理）有效缓解了这些抑制作用。与 H7 处理相比，H0.7 处理显著提高了 RGR 和 ，分别提高了 209.09%和 7.59%，增强了 / 、初级光化学最大量子产额（ ）、电子传递量子产额（ ）以及总 Rubisco 活性，分别提高了 192.31%、17.6%、36.84%和 37.08%，并且大部分上调了参与电子传递和卡尔文循环的大多数关键基因的表达。总之，低 R/FR 通过加速黄瓜植株中从 PSII 到 PQ 池的光合电子传递并促进卡尔文循环，有效缓解了盐胁迫对叶片光合作用的负面影响。它为高效抗盐蔬菜生产提供了一种新型的环保光质调控技术。
