Effects of 24-epibrassinolide and 28-homobrassinolide on the growth and antioxidant enzyme activities in the seedlings of Brassica juncea L.

Abstract

The present paper deals with the effects of two active forms of brassinosteroids (BRs) as epibrassinosteroid (24-EBL) and homobrassinosteroid (28-HBL) on percentage germination, growth in the form of shoot length, activities of auxinase (IAAO), polyphenol oxidase (PPO), superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APOX) in 10 day old seedlings of Brassica juncea L. (RCM 619) under field conditions. Exogenous application of 240-EBL and 28-HBL significantly ameliorate the total protein content as compared to untreated control seedlings. 10(-8) M 28-HBL helps in enhancing the PPO activity very significantly, as compared to all other concentrations of EBL and HBL and also to that of untreated control. Similar trend was observed in IAAO activity. It was observed that all the concentrations of EBL were unable to enhance the APOX activity as compared to untreated control seedlings but 10(-8) M HBL significantly ameliorates APOX activity. CAT and SOD activities ameliorate significantly with exogenous application of EBL and HBL. Out of two active forms of BRs, 28-HBL was more effective at germination stage in scavenging the free radicals, which are produced in greater amount during germination from basic metabolic processes, whereas 28-EBL was effective in the initial growth of seedlings in the form of increase in shoot length.

In VitroEffects of Brassinosteroids on the Growth and Antioxidant Enzyme Activities in Groundnut

“…An increase in CAT activity after treatment with BR has also been reported earlier in rice [11], groundnut [37], Zea mays L. [10,38], tomato [39], Brassica juncea L. [40,41], and so forth. It may be inferred from the enhancement in CAT activity that BR application modulated the antioxidative metabolism resulting in better growth of plants as suggested earlier [42,43].…”

“…It may be inferred from the enhancement in CAT activity that BR application modulated the antioxidative metabolism resulting in better growth of plants as suggested earlier [42,43]. An increase in POX activity in response to the application of BRs has also been reported [40,41,44]. The POX has been implicated in the synthesis of lignin and other phenolic polymers.…”

“…The enhancement in POX activity might defend the cells against harmful concentrations of hydroperoxides. Sirhindi et al [41] also observed an increase in the activity of PPX after exogenous application of 28-homobrassinolide in seedlings of Brassica juncea L. Activity of APX was found to be consistent with the earlier reports in which APX activity was stimulated after the application of 24-epibrassinolide [39,40,45] and 2-homobrassinolide [46] and brassinolide analogue BR-16 [11]. The decline in MDA level indicated that BR treatment caused a decrease in lipid peroxidation in the in vitro grown leaves of groundnut plants.…”

Effect of Integrated Nutrient Management and Bio-regulators on Yield and Economics Attributes of Sprouting Broccoli {Brassica oleracea (L.) var. italica}

“…Brassinosteroids also enhances the crop productivity [6]. Brassinostroids being an eco-friendly chemical, has a potential application in agriculture to increase yield by regulating defense system under field condition in Brassica juncea L. Sirhindi et al [7]. Mitchell et al [8] reported about promotion in stem elongation and cell division by the treatment of organic extracts of rapeseed pollen.…”

Effects of homobrassinolide in barley callus culture

“…BR stimulated somatic embryogenesis in cotton (Aydin et al 2006). BRs increased protein content and CAT and SOD activity in Brassica juncea L. under field conditions (Sirhindi et al 2009). However, HBL decreased protein content and SOD, catalase (EC 1.11.1.6) and peroxidase (EC 1.11.1.11) activities in germinating barley embryos (Kartal et al 2009).…”