黄瓜花期高温胁迫对叶片衰老特性和内源激素的影响

Effects of high temperature stress on senescence and endogenous hormone of cucumber during flowering period

为了研究黄瓜花期高温胁迫对植株叶片衰老特性及内源激素的影响,本研究以黄瓜‘南杂2号’(Nan ZaⅡ)品种为试材,利用人工气候箱设计3个温度处理:昼温/夜温分别为36℃/26℃、39℃/29℃、42℃/32℃,以昼温/夜温24℃/18℃为对照(CK),持续时间设计1、3、5和7 d。处理完成后分别测定黄瓜叶片叶绿素含量、抗氧化酶活性、MDA含量和顶芽内源激素含量。结果表明:42℃/32℃处理7 d时黄瓜叶片叶绿素a、叶绿素b、类胡萝卜素含量,POD、SOD活性,顶芽IAA、GA3、ZT含量分别较CK降低了16.61%、23.17%、73.33%、17.89%、56.90%、94.16%、54.32%、90.68%;而叶片MDA含量、CAT活性和顶芽ABA含量分别较CK增加了62.66%、28.06%和294.35%;短期高温胁迫增加了黄瓜叶片的叶绿素含量,随着温度的升高,胁迫时间的延长叶片叶绿素b含量逐渐降低;短期高温胁迫增加了叶片抗氧化酶活性,随着高温胁迫的加剧,抗氧化酶活性表现出逐渐降低的趋势;高温胁迫下黄瓜顶芽ABA含量表现出增加的趋势,而IAA、GA3和ZT含量的变化则相反。本研究揭示了黄瓜花期高温胁迫下叶片衰老特性和内源激素含量的变化规律,为黄瓜栽培的温度管理提供科学依据。

To explore the effects of high temperature stress on the senescence characteristics and the dynamics of endogenous hormones in leaves of cucumber at flowering stage, we established an artificial environment within which temperature was controlled and selected cuhivar‘Nan Za Ⅱ ＇ as experiment material. Four levels of daily/night temperature were treated as 42 ℃/32 ℃, 39 ℃/29 ℃, 36 ℃/26 ℃, and 24 ℃/18 ℃ （control） ; the durations of treatment time were 1, 3, 5, and 7 d, respectively. The contents of chlorophyll a, chlorophyll b, carotenoids and chlorophyll a＋b, the activities of SOD, POD and CAT, and the content MDA, ABA, IAA, GA3 and ZT were measured. Treatment of 42 ℃/32 ℃ with a duration of 7 d significantly reduced the contents of leaf chlorophyll a, chlorophyll b, and carotenoids, the activities of POD and SOD, and the contents of IAA, GA3, and ZT by 16.61%, 23.17%, 73.33%, 17.89%, 56.90%, 94.16%, 54.32%, 90.68%, respectively, but enhanced leaf MDA content （＋62.66%） , CAT activity （＋28.06%）, and ABA content （＋294.35%） in apical bud. Our results showed that short-term high temperature stress increased the chlorophyll content of cucumber leaves and that the chlorophyll b content decreased gradually with the increase of temperature and extension of stress time. Short-term high temperature stress increased the activities of antioxidant enzymes in cucumber leaves, but decreased gradually with the increased intensity of high temperature stress. An increasing trend of ABA content in cucumber leaves was detected under high temperature stress, while the c this study provide hanges of IAA, GA3 and ZT contents showed an opposite trend. Resuhs from scientific basis for temperature management of cucumber cultivation.