Abstract: This study evaluated the effects of exogenous hydrogen sulfide (H₂S) on the physiological characteristics and endogenous hormones in tall fescue (Festuca arundinacea schyeb. cv. ‘Arid 3’) seedlings under low-light stress. The seedlings of Arid 3 under low-light stress were sprayed with sodium hydrosulfide (NaHS, H₂S donor), hypotaurine (HT, H₂S scavenger), aminooxy acetic acid (AOA, H₂S biosynthesis inhibitor), and distilled water respectively;and the indicators of germination characteristics, membrane stability, root vitality and endogenous hormones were determined. The results showed that exogenous H₂S significantly increased the germination rate, germination potential, vitality index, endogenous H₂S and abscisic acid (ABA) contents under low-light stress. Meanwhile, malondialdehyde (MDA) and superoxide anion (O₂^·-), relative electrolyte leakage, and gibberellin (GA) levels were decreased by 17.5%, 11.0%, and 23.0%, respectively. However, the HT or AOA treatment inhibited the effects of exogenous H₂S. It indicates that exogenous H₂S can increase ABA level, improve germination characteristics, maintain the membrane stability and integrity under low-light stress, thereby alleviate oxidative damage and enhance the adaption to low-light stress in tall fescue seedlings.

Key words: Tall fescue, Low light, Hydrogen sulfide, Physiological characteristics, Endogenous hormones

摘要： 为了探讨外源硫化氢（H₂S）在弱光胁迫下对高羊茅（Festuca arundinacea）生理特性和内源激素的调节作用，本文以高羊茅品种Arid 3号为试验材料，在弱光胁迫下分别喷施外源H₂S供体（NaHS）、H₂S清除剂次牛磺酸（HT）、H₂S合成酶抑制剂羧甲基胺半盐酸盐（AOA）和蒸馏水，测定其对高羊茅萌发特性、细胞膜稳定性、根活力和内源激素的影响。结果表明：弱光下施加H₂S显著提高了发芽率、发芽势、活力指数、内源H₂S和脱落酸（ABA）含量，同时降低了丙二醛（MDA）、细胞膜透性和超氧阴离子（O₂^·-），且较单独遮荫处理分别降低了17.5%，23.0%和11.0%；而施加HT和AOA会抑制内源H₂S的效果。综上，H₂S能够提高弱光胁迫下高羊茅的ABA水平，增强萌发特性，维持细胞膜的稳定性和完整性，从而减轻弱光胁迫引起的细胞膜氧化损伤，提高高羊茅对弱光胁迫的适应能力。

关键词: 高羊茅, 弱光胁迫, 硫化氢, 生理特性, 内源激素