title: Chromium stress mitigation by polyamine-brassinosteroid application involves phytohormonal and physiological strategies in Raphanus sativus L.
abstract: Brassinosteroids (BRs) and polyamines (PAs) are well-established growth regulators playing key roles in stress management among plants. In the present study, we evaluated the effects of epibrassinolide (EBL, an active BR) and spermidine (Spd, an active PA) on the tolerance of radish to oxidative stress induced by Cr (VI) metal. Our investigation aimed to study the impacts of EBL (10(-9) M) and/or Spd (1 mM) on the biochemical and physiological responses of radish (Raphanus sativus L.) under Cr-stress. Applications of EBL and/or Spd were found to improve growth of Cr-stressed seedlings in terms of root length, shoot length and fresh weight. Our data also indicated that applications of EBL and Spd have significant impacts, particularly when applied together, on the endogenous titers of PAs, free and bound forms of IAA and ABA in seedlings treated with Cr-stress. Additionally, co-applications of EBL and Spd modulated more remarkably the titers of antioxidants (glutathione, ascorbic acid, proline, glycine betaine and total phenol) and activities of antioxidant enzymes (guaicol peroxidase, catalase, superoxide dismutase and glutathione reductase) in Cr-stressed plants than their individual applications. Attenuation of Cr-stress by EBL and/or Spd (more efficient with EBL and Spd combination) was also supported by enhanced values of stress indices, such as phytochelatins, photosynthetic pigments and total soluble sugars, and reduction in malondialdehyde and H(2)O(2) levels in Cr-treated seedlings. Diminution of ROS production and enhanced ROS scavenging capacities were also noted for EBL and/or Spd under Cr-stress. However, no significant reduction in Cr uptake was observed for co-application of EBL and Spd when compared to their individual treatments in Cr-stressed seedlings. Taken together, our results demonstrate that co-applications of EBL and Spd are more effective than their independent treatments in lowering the Cr-induced oxidative stress in radish, leading to improved growth of radish seedlings under Cr-stress.
authors.affiliation: Department of Horticulture, Zhejiang University, Hangzhou, Zhejiang, China. sikanderchowdhary@gmail.com
authors.forename: Sikander Pal
authors.initials: SP
authors.lastname: Choudhary
authors.forename: Mukesh
authors.initials: M
authors.lastname: Kanwar
authors.forename: Renu
authors.initials: R
authors.lastname: Bhardwaj
authors.forename: Jing-Quan
authors.initials: JQ
authors.lastname: Yu
authors.forename: Lam-Son Phan
authors.initials: LS
authors.lastname: Tran
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000975:Antioxidants / Q000378:metabolism; D060406:Brassinosteroids / Q000378:metabolism / Q000494:pharmacology*; D002374:Catalase / Q000378:metabolism; D002857:Chromium / Q000378:metabolism / Q000633:toxicity*; D004789:Enzyme Activation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005980:Glutathione Reductase / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D019255:NADPH Oxidases / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism / Q000494:pharmacology*; D031224:Raphanus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D013095:Spermidine / Q000378:metabolism / Q000494:pharmacology; D013312:Stress, Physiological / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000378:metabolism; D014131:Trace Elements / Q000378:metabolism / Q000633:toxicity
chemical_list: D000975:Antioxidants; D060406:Brassinosteroids; D007210:Indoleacetic Acids; D045332:Photosystem II Protein Complex; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011073:Polyamines; D014131:Trace Elements; D002857:Chromium; C030737:indoleacetic acid; D000040:Abscisic Acid; C121048:guaiacol peroxidase; D002374:Catalase; D009195:Peroxidase; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D005980:Glutathione Reductase; D013095:Spermidine