Liu Mingxi, Chen Jingjing, Guo Zhenfei, Lu Shaoyun
Department of Grassland Science, College of Agronomy, Hunan Agricultural UniversityChangsha, China.
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Sciences, Guangdong Engineering Research Center for Grassland Science, South China Agricultural UniversityGuangzhou, China.
Front Plant Sci. 2017 May 16;8:792. doi: 10.3389/fpls.2017.00792. eCollection 2017.
Centipedegrass ( [Munro] Hack.) is an important warm-season turfgrass species with low turf maintenance requirements. However, our knowledge on physiological adaptation of centipedegrass to drought stress is limited. Physiological responses to drought in a gamma-ray-induced mutant 22-1 as compared with two wild type (WT) lines were analyzed for understanding of drought tolerance mechanism of centipedegrass. The mutant showed an elevated drought tolerance with higher levels of relative water content, net photosynthetic rate () and stomatal conductance () and lower levels of ion leakage and malondialdehyde (MDA) under drought stress as compared with WT plants. showed significant correlation with and MDA. Higher levels of antioxidant enzymes activities, non-enzyme antioxidants, and polyamines including putrescine (Put), spermidine (Spd), and spermine (Spm) were maintained in 22-1 than in WT plants. Superoxide dismutase (SOD), catalase (CAT), ascorbate-peroxidase (APX), and glutathione reductase (GR) activities and ascorbic acid (AsA) content were significantly correlated with both Put and Spd levels, and reduced glutathione level was correlated with Put during drought stress. Exogenous application of Put, Spd, and Spm increased drought tolerance and activities of SOD, CAT, APX, and GR in WT plants. The results suggest that higher levels of polyamines and antioxidant defense system are associated with the elevated drought tolerance in 22-1, which may improve protection on photosynthesis against drought induced oxidative damage.
假俭草（[芒罗]哈克）是一种重要的暖季型草坪草种，对草坪养护要求较低。然而，我们对假俭草干旱胁迫生理适应性的了解有限。为了了解假俭草的耐旱机制，分析了γ射线诱导突变体22-1与两个野生型（WT）品系在干旱胁迫下的生理反应。与野生型植株相比，突变体在干旱胁迫下表现出更高的耐旱性，相对含水量、净光合速率（）和气孔导度（）水平更高，离子渗漏和丙二醛（MDA）水平更低。与MDA显著相关。与野生型植株相比，22-1中抗氧化酶活性、非酶抗氧化剂和包括腐胺（Put）、亚精胺（Spd）和精胺（Spm）在内的多胺水平更高。超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、抗坏血酸过氧化物酶（APX）和谷胱甘肽还原酶（GR）活性以及抗坏血酸（AsA）含量与Put和Spd水平均显著相关，干旱胁迫期间还原型谷胱甘肽水平与Put相关。外源施用Put、Spd和Spm可提高野生型植株的耐旱性以及SOD、CAT、APX和GR的活性。结果表明，较高水平的多胺和抗氧化防御系统与22-1中耐旱性的提高有关，这可能会增强对光合作用的保护，抵御干旱诱导的氧化损伤。
