| 缐旭林,张德,张仲兴,王双成,高彦龙,王延秀.2,4-表油菜素内酯对干旱胁迫下垂丝海棠生理特性的影响[J].干旱地区农业研究,2022,40(3):37~45 |
| 2,4-表油菜素内酯对干旱胁迫下垂丝海棠生理特性的影响 |
| Effects of 2,4-Epibrassinolide on physiological characteristics of Malus halliana under drought stress |
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| DOI：10.7606/j.issn.1000-7601.2022.03.05 |
| 中文关键词: 垂丝海棠 2，4-表油菜素内酯 干旱胁迫 生理特性 抗氧化酶 |
| 英文关键词:Malus halliana 2,4-Epibrassinolide drought stress photosynthetic characteristics antioxidant enzyme |
| 基金项目:国家自然科学基金（31960581）；甘肃省自然科学基金（18JR3RA171） |
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| 中文摘要: |
| 以7~8叶龄的垂丝海棠实生苗为试验材料，研究外源喷施2,4-表油菜素内酯（EBR）对干旱胁迫下垂丝海棠幼苗光合及生理特性的影响。采用盆栽控水法，设置CK（正常水分）与干旱胁迫加6种浓度油菜素内酯处理，即T1（0 mg·L-1）、T2（0.20 mg·L-1）、T3（0.40 mg·L-1）、T4（0.60 mg·L-1）、T5（0.80 mg·L-1）和T6（1.00 mg·L-1），分别测定各处理下叶绿素含量、光合特性、抗氧化酶活性及渗透调节物质含量，并进行相关性与主成分分析。随干旱胁迫时间的延长，垂丝海棠叶片的Chl a、Chl b、Chl a+b、Chl a/b、净光合速率（Pn）、气孔导度（Gs）和蒸腾速率（Tr）均呈下降趋势；胞间CO2浓度（Ci）、丙二醛（MDA）含量和相对电导率（REC）呈上升趋势；脯氨酸（Pro）含量、超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性呈先升后降的趋势。与T1处理相比，喷施外源油菜素内酯处理下的垂丝海棠叶片各项指标的变化幅度均有所减小，且存在浓度效应；胁迫至9 d时，0.2 mg·L-1（T2）处理Chl a、Chl b、Chl a+b、Chl a/b、Pn、Gs、Tr均显著高于其它喷施外源油菜素内酯处理，与CK相比，分别为CK的88.21%、97.67%、93.95%、90.32%、76.72%、66.23%、85.76%；Ci、MDA、REC显著低于其它喷施外源油菜素内酯处理，分别为CK的1.27倍、1.11倍、1.12倍、1.93倍。相关性分析结果表明，垂丝海棠叶片的Pn与Chl a、Chl b、Chl a+b、Chl a/b、Gs呈极显著正相关（P<0.01），与Tr呈显著正相关（P<0.05），与REC、Ci呈极显著负相关（P<0.01）。主成分分析提取到特征值>1的2个主成分，方差贡献率分别为69.75%、26.77%，累积方差贡献率达到96.52%。根据主成分得分排名可知，外源2,4-表油菜素内酯对垂丝海棠干旱胁迫的缓解能力为：T2>T3>T4>T5>T6>T1。0.20 mg·L-1油菜素内酯可通过提高抗氧化酶活性，减轻细胞膜氧化损伤，从而增强垂丝海棠幼苗对干旱胁迫的耐受性，并通过提高叶片对光能的捕获和转化能力，增强叶片光合能力，促进垂丝海棠幼苗生长。 |
| 英文摘要: |
| The effects of exogenous 2,4-Epibrassinolide (EBR) on the photosynthesis and physiological characteristics of Malus halliana seedlings under drought stress with seedlings of 7~8 leaf\|age Malus halliana as experimental materials were studied. The experiment used pot water control method of CK (normal water level) and drought stress as well as 6 brassinolide concentrations of T1 (0 mg·L-1), T2 (0.2 mg·L-1), T3 (0.4 mg·L-1), T4 (0.6 mg·L-1), T5 (0.8 mg·L-1) and T6 (1 mg·L-1). The contents of chlorophyll, photosynthetic characteristics, antioxidant enzyme activity, relative electrical conductivity and osmotic regulating substances in each treatment were measured, and the correlation and principal component analysis were computed. With the extension of drought stress time, Chl a, Chl b, Chl a+b, Chl a/b, net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr) decreased, and intercellular CO2 concentration (Ci), malonaldehyde (MDA), relative electrical conductivity (REC) increased. The activities of proline (Pro), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) increased first and then decreased. Additionally, compared with the control group, the increase and decrease of each index of Malus halliana leaves decreased to different degrees after spraying different concentrations of exogenous brassinolide, and there was a concentration effect. Among them, under 0.2 mg·L-1 (T2) treatment, Chl a, Chl b, Chl a+b, Chl a/b, Pn, Gs and TR decreased the least, significantly higher than those in T1, while MDA and REC increased the most, which were significantly higher than those in T1. Subsequently, correlation analysis of 14 indexes showed that Pn was significantly positively correlated with Chl a, Chl b, Chl a+b, Chl a/b and Gs (P<0.01) and Tr (P<0.05), and negatively correlated with REC and Ci (P<0.01). In addition, the 14 indexes were analyzed by principal component analysis, and the two principal components with eigenvalue >1 were extracted, whose eigenvalues were 9.765 and 3.747, respectively. The variance contribution rates were 69.747% and 26.766%, respectively, and the cumulative variance contribution rate reached 96.513%, which met the requirements. Finally, according to the ranking of principal component scores, the alleviating ability of exogenous brassinolide to drought stress of Malus halliana was T2>T3>T4>T5>T6>T. The 0.2 mg·L-1 brassinolide treatment had better results in improving the photosynthetic capacity, enhancing the activity of antioxidant enzymes, and promoting the stability of membrane to alleviate drought stress. |
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