Rakhmankulova Zulfira, Shuyskaya Elena, Toderich Kristina, Voronin Pavel
K.A. Timiryazev Institute of Plant Physiology RAS, IPP RAS, 35 Botanicheskaya St., 127276 Moscow, Russia.
International Platform for Dryland Research and Education, Tottori University, 1390 Hamasaka, Tottori 680-0001, Japan.
Plants (Basel). 2021 Mar 5;10(3):491. doi: 10.3390/plants10030491.
A significant increase in atmospheric CO concentration and associated climate aridization and soil salinity are factors affecting the growth, development, productivity, and stress responses of plants. In this study, the effect of ambient (400 ppm) and elevated (800 ppm) CO concentrations were evaluated on the C xero-halophyte treated with moderate salinity (200 mM NaCl) and polyethylene glycol (PEG)-induced osmotic stress. Our results indicated that plants grown at elevated CO concentration had different responses to osmotic stress and salinity. The synergistic effect of elevated CO and osmotic stress increased proline accumulation, but elevated CO did not mitigate the negative effects of osmotic stress on dark respiration intensity and photosystem II (PSII) efficiency. This indicates a stressful state, which is accompanied by a decrease in the efficiency of light reactions of photosynthesis and significant dissipative respiratory losses, thereby resulting in growth inhibition. Plants grown at elevated CO concentration and salinity showed high Na and proline contents, high water-use efficiency and time required to reach the maximum P700 oxidation level (PSI), and low dark respiration. Maintaining stable water balance, the efficient functioning of cyclic transport of PSI, and the reduction of dissipation costs contributed to an increase in dry shoot biomass (2-fold, compared with salinity at 400 ppm CO). The obtained experimental data and PCA showed that elevated CO concentration improved the physiological parameters of under salinity.
大气中二氧化碳（CO）浓度的显著增加以及相关的气候干旱化和土壤盐渍化是影响植物生长、发育、生产力和应激反应的因素。在本研究中，评估了环境浓度（400 ppm）和升高浓度（800 ppm）的CO对经中度盐度（200 mM NaCl）和聚乙二醇（PEG）诱导的渗透胁迫处理的旱生盐生植物的影响。我们的结果表明，在升高的CO浓度下生长的植物对渗透胁迫和盐度有不同的反应。升高的CO与渗透胁迫的协同作用增加了脯氨酸的积累，但升高的CO并未减轻渗透胁迫对暗呼吸强度和光系统II（PSII）效率的负面影响。这表明处于应激状态，伴随着光合作用光反应效率的降低和显著的呼吸耗散损失，从而导致生长抑制。在升高的CO浓度和盐度下生长的植物表现出高钠和脯氨酸含量、高水分利用效率以及达到最大P700氧化水平（PSI）所需的时间，并且暗呼吸较低。维持稳定的水分平衡、PSI循环运输的有效运作以及耗散成本的降低有助于增加地上部干生物量（与400 ppm CO浓度下的盐度相比增加了2倍）。获得的实验数据和主成分分析表明，升高的CO浓度改善了盐度下植物的生理参数。
