Modulation of antioxidant enzymes in Juniperus procera needles in relation to habitat environment and dieback incidence
Modulation of antioxidant enzymes in Juniperus procera needles in relation to habitat environment and dieback incidence
复制标题
DOI：
10.1007/s00468-016-1399-0
复制
发表时间：
2016-10-01
影响因子：
2.3
通讯作者：
Iqbal, Muhammad
中科院分区：
文献类型：
--
作者：
Aref, Ibrahim M.;Khan, Pervaiz R.;Iqbal, Muhammad
氧化应激和抗氧化酶活性在受损的杜松树上高于健康的杜松树，在夏季高于冬季，在干燥条件下高于潮湿条件。沙特阿拉伯的许多小型杜松林（主要集中在该国南部的阿西尔山脉）正遭受枝条顶枯病的困扰。作为健康和受顶枯病影响的树木对 Al-Ghalab、Al-Yazeed 和 Saodah 地区当地环境条件的结构和功能反应项目的一部分，本研究量化了产生的氧化应激以及随之而来的脯氨酸积累和抗氧化酶活性的调节，通过对夏季和冬季采集的针叶组织样本进行化学分析来确定。表明氧化应激程度的TBARS水平在Al-Ghalab最低(10.1 nM g(-1) f w)，在Al-Yazeed最高(28.1 nM g(-1) f w)，夏季相对高于冬季。健康树木的 TBARS 水平低于枯死树木。健康树中脯氨酸含量为 147-54 A mu g g(-1)，受影响树中脯氨酸含量为 460-99 A mu g g(-1) f w。健康树中超氧化物歧化酶、抗坏血酸过氧化物酶、谷胱甘肽还原酶和过氧化氢酶的活性变化分别约为0.7-3.6、0.01-0.09、0.02-0.08和0.6-3.0 U mg(-1) min(-1)，而在2.3-6.1、0.04-0.3、在不同地点受顶枯病影响的树木中分别为0.04-0.3和2-5.8 U mg(-1) min(-1)。因此，受损树木的氧化应激和酶刺激高于健康树木，夏季高于冬季。收集地点的集水工作显示出改善效果。我们的观察表明，通过在受干旱影响的地区采取适当的集水策略来改善土壤水的可用性，可以使 J. procera 树对压力条件更加耐受，甚至可以避免或最小化枯萎的风险。
Oxidative stress and the antioxidant enzymes' activity are higher in damaged than in healthy Juniperus procera trees, in summer than in winter, and in dry than in wet condition.Many of the small stands of Juniperus procera in Saudi Arabia, confined mainly to Aseer Mountains in the southern part of the country, are suffering from branch dieback. As a part of the project on the structural and functional responses of healthy and dieback-affected trees to local environmental conditions of Al-Ghalab, Al-Yazeed, and Saodah locations, this study quantifies the oxidative stress generated and the consequent modulation of proline accumulation and antioxidant enzymes' activity, as determined by chemical analysis of needle tissues from samples collected in summer and winter seasons. The level of TBARS, which indicated the extent of oxidative stress, was minimum (10.1 nM g(-1) f w) at Al-Ghalab and maximum (28.1 nM g(-1) f w) at Al-Yazeed, being relatively higher in summer than in winter. Healthy trees had a lower level of TBARS than those suffering from dieback. Proline content showed 147-54 A mu g g(-1) in healthy trees and 460-99 A mu g g(-1) f w in affected ones. Variation in the activity of superoxide dismutase, ascorbate peroxidase, glutathione reductase, and catalase was around 0.7-3.6, 0.01-0.09, 0.02-0.08, and 0.6-3.0 U mg(-1) min(-1), respectively, in healthy trees, whereas 2.3-6.1, 0.04-0.3, 0.04-0.3, and 2-5.8 U mg(-1) min(-1), respectively, in the dieback-affected trees of the different locations. Thus, the oxidative stress and the enzymatic stimulation were higher in damaged than in healthy trees and in summer than in winter season. Water-harvesting efforts at the collection sites showed ameliorative effects. Our observations suggest that J. procera tree can be made more tolerant toward stressful condition, and even the risk of dieback can be avoided or minimized by improving soil-water availability through adequate water-harvesting strategies in the drought-affected areas.