State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
Xinjiang Key Laboratory of Desert Plant Roots Ecology and Vegetation Restoration, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
Physiol Plant. 2021 Dec;173(4):2307-2322. doi: 10.1111/ppl.13581. Epub 2021 Oct 14.
Plants are subjected to salt and drought stresses concurrently but our knowledge about the effects of combined stress on plants is limited, especially on halophytes. We aim to study if some diverse drought and salt tolerance traits in halophyte may explain their tolerance to salinity and drought stresses, individual and in combination, and identify key traits that influence growth under such stress conditions. Here, the halophyte Halogeton glomeratus was grown under control, single or combinations of 60 days drought and salt treatments, and morphophysiological responses were tested. Our results showed that drought, salinity, and combination of these two stressors decreased plant growth (shoot height, root length, and biomass), leaf photosynthetic pigments content (chlorophyll a, b, a + b and carotenoids), gas exchange parameters (Net photosynthesis rate [P ], transpiration rate [E], stomatal conductance [g ]), and water potential (ψ ), and the decreases were more prominent under combined drought and salinity treatment compared with these two stressors individually performed. Similarly, combined drought and salinity treatment induced more severe oxidative stress as indicated by more hydrogen peroxide (H O ) and malondialdehyde (MDA) accumulated. Nevertheless, H. glomeratus is equipped with specific mechanisms to protect itself against drought and salt stresses, including upregulation of superoxide dismutases (SOD; EC 1.15.1.1) and catalase (CAT; EC 1.11.1.6) activities and accumulation of osmoprotectants (Na , Cl , and soluble sugar). Our results indicated that photosynthetic pigments content, gas exchange parameters, water potential, APX activity, CAT activity, soluble sugar, H O , and MDA are valuable screening criteria for drought and salt, alone or combined, and provide the tolerant assessment of H. glomeratus.
植物同时受到盐和干旱胁迫的影响，但我们对植物受到联合胁迫的影响的了解是有限的，尤其是对盐生植物。我们旨在研究盐生植物的一些不同的耐旱和耐盐特性是否可以解释它们对盐度和干旱胁迫的耐受性，无论是单独的还是组合的，并确定影响这些胁迫条件下生长的关键特性。在这里，盐生植物盐节木在对照、单一或组合的 60 天干旱和盐处理下生长，并测试了形态生理响应。我们的结果表明，干旱、盐度以及这两种胁迫因素的组合降低了植物的生长（茎高、根长和生物量）、叶片光合作用色素含量（叶绿素 a、b、a+b 和类胡萝卜素）、气体交换参数（净光合速率[P ]、蒸腾速率[E]、气孔导度[g ]）和水势（ψ ），与这两种胁迫因素单独处理相比，在组合干旱和盐胁迫处理下，这些下降更为显著。同样，组合的干旱和盐胁迫处理诱导了更严重的氧化应激，表现为更多的过氧化氢（H O ）和丙二醛（MDA）积累。然而，盐节木具有特定的机制来保护自己免受干旱和盐胁迫的影响，包括超氧化物歧化酶（SOD；EC 1.15.1.1）和过氧化氢酶（CAT；EC 1.11.1.6）活性的上调以及渗透保护物质（Na + 、Cl - 和可溶性糖）的积累。我们的结果表明，光合作用色素含量、气体交换参数、水势、APX 活性、CAT 活性、可溶性糖、H O 、和 MDA 是单独或组合使用的干旱和盐胁迫的有价值的筛选标准，并提供了盐节木耐旱和耐盐的评估。
