Coix lacryma-jobi L. is an Asian plant widely used in traditional medicine. Drought conditions can lead to an impairment of photosynthesis which can be softened by the exogenous application of proline and γ-aminobutyric acid (GABA) to maintain the electron transport chain (ETC) and avoid reactive oxygen species-induced oxidative damage by inducing antioxidative enzymes. The aim of this study was to evaluate the effects of water deficit on C. lacryma-jobi leaves under the application of proline and GABA. Chlorophyll (Chl) a fluorescence emission, antioxidative enzyme activity (catalase, superoxide dismutase, ascorbate peroxidase and guaiacol peroxidase) and proline and GABA contents in leaf tissues were performed in plants subjected to 12 days of drought. Chl a fluorescence indicated impairments on photosynthetic apparatus due to water deficit that resulted into increased activity of antioxidant enzymes. The application of proline but not GABA was more efficient in alleviating the effects of water deficit, as evidenced by the maintenance of the dynamic dissipation of the photosynthetic energy, besides the greater accumulation of proline under these conditions. Water deficit induces alterations in the ETC, which is softened by the application of proline to cope with the deleterious effects of drought in C. lacryma-jobi plant leaves.

中文翻译：

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外源施用脯氨酸和GABA氨基酸对薏苡叶干旱胁迫的影响

薏苡仁是一种广泛用于传统医学的亚洲植物。干旱条件可导致光合作用受损，可通过外源性应用脯氨酸和 γ-氨基丁酸 (GABA) 来维持电子传递链 (ETC) 并通过诱导抗氧化酶避免活性氧诱导的氧化损伤。本研究的目的是评估在脯氨酸和 GABA 的应用下水分亏缺对 C. lacryma-jobi 叶片的影响。在经受 12 天干旱的植物中进行叶绿素 (Chl) 荧光发射、抗氧化酶活性（过氧化氢酶、超氧化物歧化酶、抗坏血酸过氧化物酶和愈创木酚过氧化物酶）以及叶组织中的脯氨酸和 GABA 含量。Chl a 荧光表明由于缺水导致抗氧化酶活性增加而导致光合装置受损。除了在这些条件下脯氨酸的更多积累之外，脯氨酸而不是 GABA 的应用在减轻水分亏缺的影响方面更有效，正如光合能量的动态耗散的维持所证明的那样。缺水会引起 ETC 的改变，通过应用脯氨酸来应对干旱对 C. lacryma-jobi 植物叶片的有害影响，ETC 会发生改变。除了在这些条件下更多的脯氨酸积累。缺水会引起 ETC 的改变，通过应用脯氨酸来应对干旱对 C. lacryma-jobi 植物叶片的有害影响，ETC 会发生改变。除了在这些条件下更多的脯氨酸积累。缺水会引起 ETC 的改变，通过应用脯氨酸来应对干旱对 C. lacryma-jobi 植物叶片的有害影响，ETC 会发生改变。