Brassinosteroids protect Lycopersicon esculentum from cadmium toxicity applied as shotgun approach

Abstract

Surface-sterilized seeds of two tomato cultivars (cv. K-25 and Sarvodya) were soaked in 100 microM CdCl(2) for 8 h (shotgun approach). The resulting 59-day-old seedlings were sprayed with 10(-8) M of 28-homobrassinolide (HBL) or 24-epibrassinolide (EBL) to their foliage. Both cultivars showed significantly different response to Cd stress. Cadmium severely restricted the growth, photosynthetic efficiency, and activity of nitrate reductase (E.C. 1.6.6.1) and carbonic anhydrase (E.C. 4.2.1.1) in Sarvodya as compared to K-25. However, the activities of antioxidative enzymes were significantly higher in K-25. This result may be considered an indication of better tolerance of the K-25 cultivars to Cd stress. Moreover, the spray of both the brassinosteroids (HBL/EBL) were found very effective in neutralizing the adverse effects generated by metals that reflect in better photosynthetic performance by the cultivars. An interesting aspect of this study is that HBL or EBL spray caused a further increase in proline content and antioxidative enzyme activities, which were already enhanced by Cd stress. This effect of brassinosteroids (HBL/EBL) was more pronounced in K-25 than in Sarvodya, representing the tolerance and adoptable behavior of K-25.

24-epibrassinolide regulated diminution of Cr metal toxicity in Brassica juncea L. plants

“…The level of these enzymes is increased by the action of 24-epiBL to overcome the stress generated by Cr and to enhance the resistance capacity of plants (Figure 1-3). This data is consistent with the studies that exogenous BRs treatment is effective in ameliorating stressful conditions rather than in optimal conditions (Sasse, 1997, Bhardwaj et al, 2007, Sharma and Bhardwaj, 2007bArora et al, 2008, Hayat et al, 2009. Similarly, Sharma et al, (2007) reported that pre-sowing treatments of 28-homobrassinolide lowered the uptake of metal and enhanced the activities of antioxidative enzymes and protein concentration of 7-d old B. juncea seedlings under zinc metal stress.…”

Role of Exogenous 24-Epibrassinolide in Enhancing the Salt Tolerance of Wheat Seedlings

“…Spray of EBR under salt stress increased the RWC compared with only NaCl treatment, especially 10 nM EBR. Increased RWC by BRs application had been reported for Brassica juncea (Hayat et al, 2010) under cadmium stress and Vigna radiata (Ali et al, 2008) under aluminium stress.…”

“…Moreover, BRs are also reported to have an ameliorative effect on plants subjected to environmental stress such as drought stress (Hua et al, 2013), cold stress (Hu et al, 2010), heat stress (Zhang et al, 2013) and heavy metals (Hayat et al, 2010, Fariduddin et al, 2015. Karlidag et al (2011) demonstrated that BRs can mitigate the adverse effects of salt stress on stomatal conductance, membrane permeability, and leaf water content, ionic composition in salt stressed strawberry, and Derevyanchuk et al (2015) also indicated that BRs can stimulate total respiration rate in Arabidopsis thaliana leaf, particularly alternative respiratory pathway, under salt stress conditions.…”

24-epibrassinolide induced antioxidative defense system of Brassica juncea L. under Zn metal stress

“…SOD, CAT, POD, APOX, GR, MDHAR and DHAR. Earlier reports also showed that exogenous application of BRs modified antioxidant enzyme activity Ali et al 2007;Hayat et al 2009). Nunez et al (2003) observed higher activity of antioxidative enzymes in rice, grown under salinity and supplemented with polyhydroxylated spirostanic brassinosteroid analogue (BB-16).…”