Tall fescue ( Festuca arundinacea Schreb.) is a widely used cool-season turfgrass, and its growth is mainly limited by water deficit. Abscisic acid (ABA) and brassinolide (BR) are two important stress hormones regulating plant physiological processes and growth under water deficit. To investigate effects of exogenous ABA and BR on physiological and photosynthetic performance of tall fescue under water stress conditions, ABA (10 and 20 mg L −1 ) and BR (0.4 and 0.8 mg L −1 ) were applied individually and in combination (0.4 mg L −1 BR and 10 mg L −1 ABA) under three soil water regimes [75 ± 5% FC (HW), 50 ± 5% FC (MW) and 25 ± 5% FC (LW)] in the greenhouse. Results revealed that ABA and BR application markedly decreased the relative conductivity and malondialdehyde, notably increased leaf relative water content, antioxidant enzyme activity and proline content under water stress. ABA plus BR application was equally effective in improving the activities of antioxidant enzyme as ABA at 20 mg L −1 . ABA application reduced stomatal conductance and decreased both transpiration and net photosynthetic rate ( P n ), while BR application significantly increased P n and water use efficiency (WUE) by enhancing chlorophyll content. The ABA and BR combination application showed higher P n and WUE as well as BR single application. It indicated that ABA and BR combination application increased photosynthetic capacity, and reduced the effect on photosynthetic loss caused by ABA under water stress. All these confirmed that ABA plus BR application exhibited a synergistic interaction on enhancing drought tolerance and photosynthesis of tall fescue under water stress.
Xuecheng Li,Changyi Li,Ziyu Chen,Jiahui Wang,Jie Sun,Jun Yao,Ke Chen,Zhenghui Li,Hengpeng Ye
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous at relatively high concentrations by atmospheric deposition, and they are threatening to the environment. In this study, the toxicity of naphthalene on tall fescue and its potential responding mechanism was first studied by integrating approaches. Tall fescue seedlings were exposed to 0, 20, and 100 mg L −1 naphthalene in a hydroponic environment for 9 days, and toxic effects were observed by the studies of general physiological studies, chlorophyll fluorescence, and root morphology. Additionally, Ultra Performance Liquid Chromatography - Electrospray Ionization - High-Resolution Mass Spectrometry (UPLC-ESI-HRMS) was used to depict metabolic profiles of tall fescue under different exposure durations of naphthalene, and the intrinsic molecular mechanism of tall fescue resistance to abiotic stresses. Tall fescue shoots were more sensitive to the toxicity of naphthalene than roots. Low-level exposure to naphthalene inhibited the electron transport from the oxygen-evolving complex (OEC) to D1 protein in tall fescue shoots but induced the growth of roots. Naphthalene induced metabolic change of tall fescue roots in 12 h, and tall fescue roots maintained the level of sphingolipids after long-term exposure to naphthalene, which may play important roles in plant resistance to abiotic stresses.
危险品化学品经营许可证（带存储）