Department of Botany, University of Jammu, Jammu, India.
Chemosphere. 2011 Jul;84(5):592-600. doi: 10.1016/j.chemosphere.2011.03.056. Epub 2011 May 10.
The present investigation determined the effects of epibrassinolide (EBL) on the levels of indole-3-acetic acid (IAA), abscisic acid (ABA), and polyamine (PA) and antioxidant potential of 7-d old Raphanus sativus L. cv. 'Pusa chetki' seedlings grown under Cr (VI) metal stress. Reduced titers of free (0.767 μg g(-1) FW) and bound (0.545 μg g(-1) FW) IAA in Cr (VI) stressed seedlings were observed over untreated control. Supplementations of EBL to Cr (VI) stressed seedlings were able to enhance both free (2.14-5.68 μg g(-1) FW) and bound IAA (2.45-7.78 μg g(-1) FW) concentrations in comparison to Cr (VI) metal treatment alone. Significant rise in free (13.49 μg g(-1) FW) and bound (12.17 μg g(-1) FW) ABA contents were noticed for Cr (VI) stressed seedlings when compared to untreated control. No significant increase in ABA contents were recorded for Cr (VI) stressed seedlings upon supplementation with EBL over Cr (VI) treatment alone. A significant increase in Put (18.40 μg g(-1) FW) and Cad (9.08 μg g(-1) FW) contents were found for 10(-9)M EBL plus Cr (VI) metal treatments when compared to Cr (VI) treatment alone. Spermidine (Spd) contents were found to decline significantly for EBL treatment alone or when supplemented with Cr (VI) treatments over untreated controls and Cr (VI) treatment alone. Antioxidant levels were found to enhance, with glutathione (57.98 mg g(-1) FW), proline (4.97 mg g(-1) FW), glycinebetaine (39.01 μmol mL(-1)), ascorbic acid (3.17 mg g(-1) FW) and phytochelatins (65.69 μmol g(-1) FW) contents noted for EBL supplemented to Cr (VI) metal solution over Cr (VI) treatment alone. Reduced activities of guaiacol peroxidase (0.391 U mg(-1) protein) and catalase (0.221 U mg(-1) protein) and enhanced activities of glutathione reductase (7.14 U mg(-1) protein), superoxide dismutase (15.20 U mg(-1) protein) and ascorbate peroxidase (4.31 U mg(-1) protein) were observed in seedlings treated with EBL plus Cr (VI) over Cr metal treatment alone. Reduced MDA (2.55 μmol g(-1) FW) and H(2)O(2) (33.24 μmol g(-1) FW) contents were recorded for 10(-9)M EBL supplemented to Cr (VI) stress over Cr (VI) treatment alone. Enhancement in free radical scavenging potential as indicated by higher values of 1,1-diphenylpicrylhydrazyl, deoxyribose and reducing power activity assays, and increased levels of phenols and soluble sugars also showed significant influence of EBL in alleviating Cr (VI) stress in radish seedlings.
本研究旨在探讨表油菜素内酯（EBL）对 7 日龄萝卜（Raphanus sativus L. cv. 'Pusa chetki'）幼苗在 Cr（VI）金属胁迫下吲哚-3-乙酸（IAA）、脱落酸（ABA）和多胺（PA）水平和抗氧化能力的影响。与未处理的对照相比，Cr（VI）胁迫的幼苗中游离（0.767 μg g(-1) FW）和结合（0.545 μg g(-1) FW）IAA 的含量降低。与单独用 Cr（VI）处理相比，EBL 处理 Cr（VI）胁迫的幼苗能够提高游离（2.14-5.68 μg g(-1) FW）和结合 IAA（2.45-7.78 μg g(-1) FW）的浓度。与未处理的对照相比，Cr（VI）胁迫的幼苗中游离（13.49 μg g(-1) FW）和结合（12.17 μg g(-1) FW）ABA 的含量显著升高。与单独用 Cr（VI）处理相比，用 EBL 处理 Cr（VI）胁迫的幼苗中 ABA 的含量没有显著增加。与单独用 Cr（VI）处理相比，10(-9)M EBL 加 Cr（VI）金属处理的腐胺（Put）（18.40 μg g(-1) FW）和亚精胺（Cad）（9.08 μg g(-1) FW）含量显著增加。EBL 处理或与 Cr（VI）处理一起补充 EBL 时，腐胺（Spd）的含量与未处理的对照和单独用 Cr（VI）处理相比均显著下降。与单独用 Cr（VI）处理相比，抗氧化水平增强，谷胱甘肽（57.98 mg g(-1) FW）、脯氨酸（4.97 mg g(-1) FW）、甘氨酸甜菜碱（39.01 μmol mL(-1)）、抗坏血酸（3.17 mg g(-1) FW）和植物螯合肽（65.69 μmol g(-1) FW）的含量增加。与单独用 Cr（VI）处理相比，用 EBL 处理 Cr（VI）金属溶液时，愈创木酚过氧化物酶（0.391 U mg(-1) 蛋白）和过氧化氢酶（0.221 U mg(-1) 蛋白）的活性降低，谷胱甘肽还原酶（7.14 U mg(-1) 蛋白）、超氧化物歧化酶（15.20 U mg(-1) 蛋白）和抗坏血酸过氧化物酶（4.31 U mg(-1) 蛋白）的活性增强。与单独用 Cr 处理相比，用 10(-9)M EBL 处理 Cr（VI）胁迫的幼苗中丙二醛（2.55 μmol g(-1) FW）和 H(2)O(2)（33.24 μmol g(-1) FW）的含量降低。1,1-二苯基-2-苦基肼基（DPPH）、脱氧核糖和还原力活性测定、酚类和可溶性糖水平的提高，表明 EBL 对缓解萝卜幼苗 Cr（VI）胁迫具有显著的自由基清除能力。
