Bashri Gausiya, Prasad Sheo Mohan
Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad, Allahabad 211002, India.
Ranjan Plant Physiology and Biochemistry Laboratory, Department of Botany, University of Allahabad, Allahabad 211002, India.
Ecotoxicol Environ Saf. 2016 Oct;132:329-38. doi: 10.1016/j.ecoenv.2016.06.015. Epub 2016 Jun 23.
In the present study, effect of exogenous indole-3-acetic acid at their different levels (i.e. low; IAAL, 10µM and high; IAAH, 100µM) were studied on growth, oxidative stress biomarkers and antioxidant enzymes (SOD, POD, CAT and GST), and metabolites (AsA and GSH) as well as enzymes (APX, GR and DHAR) of ascorbate-glutathione cycle in Trigonella foenum-graecum L. seedlings grown under cadmium (Cd1, 3mgCd kg(-1) soil and Cd2, 9mgCd kg(-1) soil) stress. Cadmium (Cd) at both doses caused reduction in growth which was correlated with enhanced lipid peroxidation and damage to membrane as a result of excess accumulation of O2(•-) and H2O2. Cd also enhanced the oxidation of AsA and GSH to DHA and GSSG, respectively which give a clear sign of oxidative stress, despite of accelerated activity of enzymatic antioxidants: SOD, CAT, POD, GST as well as APX, DHAR (except in Cd2 stress) and GR. Exogenous application of IAAL resulted further rise in the activities of these enzymes, and maintained the redox status (> ratios: AsA/DHA and GSH/GSSG) of cells. The maintained redox status of cells under IAAL treatment declined the level of ROS in Cd1 and Cd2 treated seedlings thereby alleviated the Cd toxicity and this effect was more pronounced under Cd1 stress. Contrary to this, exogenous IAAH suppressed the activity of DHAR and GR and disturbed the redox status (< ratios: AsA/DHA and GSH/GSSG) of cells, hence excess accumulation of ROS further aggravated the Cd induced damage. Thus, overall results suggest that IAA at low (IAAL) and high (IAAH) doses affected the Cd toxicity differently by regulating the ascorbate-glutathione cycle as well as activity of other antioxidants in Trigonella seedlings.
在本研究中，研究了外源吲哚 - 3 - 乙酸在不同水平（即低浓度；IAAL，10μM和高浓度；IAAH，100μM）对在镉（Cd1，3mgCd kg(-1)土壤和Cd2，9mgCd kg(-1)土壤）胁迫下生长的胡芦巴幼苗的生长、氧化应激生物标志物和抗氧化酶（超氧化物歧化酶、过氧化物酶、过氧化氢酶和谷胱甘肽 - S - 转移酶）、代谢物（抗坏血酸和谷胱甘肽）以及抗坏血酸 - 谷胱甘肽循环中的酶（抗坏血酸过氧化物酶、谷胱甘肽还原酶和脱氢抗坏血酸还原酶）的影响。两种剂量的镉均导致生长减少，这与脂质过氧化增强以及由于超氧阴离子（O2(•-)）和过氧化氢（H2O2）过量积累对膜造成的损伤相关。镉还分别将抗坏血酸和谷胱甘肽氧化为脱氢抗坏血酸（DHA）和氧化型谷胱甘肽（GSSG），这清楚地表明了氧化应激，尽管酶促抗氧化剂（超氧化物歧化酶、过氧化氢酶、过氧化物酶、谷胱甘肽 - S - 转移酶以及抗坏血酸过氧化物酶、脱氢抗坏血酸还原酶（Cd2胁迫下除外）和谷胱甘肽还原酶）的活性加速。外源施用IAAL导致这些酶的活性进一步升高，并维持了细胞的氧化还原状态（> 比值：抗坏血酸/脱氢抗坏血酸和谷胱甘肽/氧化型谷胱甘肽）。在IAAL处理下维持的细胞氧化还原状态降低了Cd1和Cd2处理幼苗中的活性氧水平，从而减轻了镉毒性，并且这种效应在Cd1胁迫下更为明显。与此相反，外源IAAH抑制了脱氢抗坏血酸还原酶和谷胱甘肽还原酶的活性，并扰乱了细胞的氧化还原状态（< 比值：抗坏血酸/脱氢抗坏血酸和谷胱甘肽/氧化型谷胱甘肽），因此活性氧的过量积累进一步加剧了镉诱导的损伤。因此，总体结果表明，低剂量（IAAL）和高剂量（IAAH）的吲哚 - 3 - 乙酸通过调节胡芦巴幼苗中的抗坏血酸 - 谷胱甘肽循环以及其他抗氧化剂的活性，对镉毒性产生不同的影响。
