Chugh Vishal, Kaur Narinder, Grewal M S, Gupta Anil K
Department of Biochemistry, Punjab Agricultural University, Ludhiana, India.
Indian J Biochem Biophys. 2013 Apr;50(2):150-8.
The role of oxidative stress management was evaluated in two maize (Zea mays L.) genotypes - Parkash (drought-resistant) and Paras (drought-sensitive), subjected to drought stress during reproductive stage. Alterations in their antioxidant pools - glutathione (GSH) and ascorbic acid (AsA) combined with activities of enzymes glutathione reductase (GR), ascorbate peroxidase (APX), peroxidase (POX) and catalase (CAT) involved in defense against oxidative stress and stress parameters, namely chlorophyll (Chl), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were investigated in flag leaves from silk emergence till maturity. The drought caused transient increase in GR, APX, POX and CAT activities in drought-tolerant genotype (Parkash) which decreased at later stages with the extended period of drought stress. However, in Paras, drought stress caused decrease in activities of GR and CAT from initial period of stress till the end of experiment, except for POX which showed slight increase in activity. A significant increase in GSH content was observed in Parkash till 35 days after silking (DAS), whereas in Paras, GSH content remained lower than irrigated till maturity. Parkash which had higher AsA and Chl contents, also showed lower H2O2 and MDA levels than Paras under drought stress conditions. However, at the later stages, decline in antioxidant enzyme activities in Parkash due to severe drought stress led to enhanced membrane damage, as revealed by the accumulation of MDA. Our data indicated that significant activation of antioxidant system in Parkash might be responsible for its drought-tolerant behavior under drought stress and helped it to cope with the stress up to a definite period. Thus, the results indicate that antioxidant status and lipid peroxidation in flag leaves can be used as indices of drought tolerance in maize plants and also as potential biochemical targets for the crop improvement programmes to develop drought-tolerant cultivars.
在两个玉米(Zea mays L.)基因型——抗旱的“Parkash”和干旱敏感的“Paras”中评估了氧化应激管理的作用,这两个基因型在生殖阶段遭受干旱胁迫。研究了它们抗氧化物质库——谷胱甘肽(GSH)和抗坏血酸(AsA)的变化,以及参与抗氧化应激的谷胱甘肽还原酶(GR)、抗坏血酸过氧化物酶(APX)、过氧化物酶(POX)和过氧化氢酶(CAT)的活性,还有胁迫参数,即从吐丝到成熟期间旗叶中的叶绿素(Chl)、过氧化氢(H2O2)和丙二醛(MDA)。干旱导致耐旱基因型(Parkash)中GR、APX、POX和CAT活性短暂增加,随着干旱胁迫时间延长,后期这些活性下降。然而,在Paras中,干旱胁迫从胁迫初期到实验结束导致GR和CAT活性下降,除了POX活性略有增加。在Parkash中,直到吐丝后35天(DAS)观察到GSH含量显著增加,而在Paras中,GSH含量直到成熟都低于灌溉处理。在干旱胁迫条件下,具有较高AsA和Chl含量的Parkash也比Paras表现出更低的H2O2和MDA水平。然而,在后期,由于严重干旱胁迫,Parkash中抗氧化酶活性下降导致膜损伤加剧,这通过MDA的积累得以揭示。我们的数据表明,Parkash中抗氧化系统的显著激活可能是其在干旱胁迫下耐旱表现的原因,并帮助它在一定时期内应对胁迫。因此,结果表明旗叶中的抗氧化状态和脂质过氧化可作为玉米植株耐旱性的指标,也可作为作物改良计划中培育耐旱品种的潜在生化靶点。