Ecological Security and Protection Key Laboratory of Sichuan Province, Mianyang Normal University, Mianyang, 621000, China.
Naiman Desertification Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
Sci Rep. 2021 Sep 20;11(1):18663. doi: 10.1038/s41598-021-98246-8.
Drought resistance of psammophyte determines survival and growth, but their responses to drought are not well understood. We conducted a pot experiment to study how physiological characteristics respond to drought and rehydration. We found that watering to 60-65% of field capacity (the control) provided more water than was required by Agriophyllum squarrosum and its leaves became yellow and slightly wilted. The total chlorophyll content and Fm (maximum fluorescence after dark adaptation) in control were lower than in the drought treatment, and both decreased after rehydration. With increasing drought duration and intensity, the relative water content (RWC), chlorophyll content, Fm, and the quantum efficiency of photosystem II (Fv/Fm) of Setaria viridis decreased, but malondialdehyde and membrane permeability increased. During the late drought, the activities of three antioxidant enzymes in A. squarrosum increased to prevent membrane lipid peroxidation; for S. viridis, only peroxidase and superoxide dismutase activities increased. After rehydration, RWC of both species increased, but Fv/Fm of A. squarrosum and Fm of S. viridis did not recover under severe drought. Our research illustrated that A. squarrosum is better adapted to arid environment than S. viridis, but the high soil moisture content is not conducive to normal growth of A. squarrosum.
沙生植物的抗旱性决定了其生存和生长能力，但人们对其抗旱响应机制的了解还很有限。我们进行了盆栽实验，以研究其生理特征对干旱和复水的响应。结果表明，当土壤含水量保持在田间持水量的 60-65%（对照）时，提供的水量超过了四合木的需水量，导致其叶片发黄、略微萎蔫。与干旱处理相比，对照处理中的总叶绿素含量和 Fm（暗适应后的最大荧光）较低，复水后两者均下降。随着干旱持续时间和强度的增加，猪毛菜的相对含水量（RWC）、叶绿素含量、Fm 和光系统 II 的量子效率（Fv/Fm）降低，而丙二醛和膜通透性增加。在干旱后期，四合木中的三种抗氧化酶活性增加，以防止膜脂过氧化；而对于节节麦，只有过氧化物酶和超氧化物歧化酶的活性增加。复水后，两种植物的 RWC 均增加，但严重干旱下，四合木的 Fv/Fm 和节节麦的 Fm 并未恢复。我们的研究表明，四合木比节节麦更能适应干旱环境，但高土壤水分含量不利于四合木的正常生长。
