CADMIUM STRESS RESPONSES IN Brassica juncea L. PLANTS THROUGH HISTOCHEMICAL AND QUALITATIVE APPROACHES
DHRITI KAPOOR *
Department of Botany, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara-Punjab-144411, India and Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar-Punjab, India.
RENU BHARDWAJ
Department of Botanical and Environmental Sciences, Guru Nanak Dev University, Amritsar-Punjab, India.
*Author to whom correspondence should be addressed.
Abstract
Major Environmental toxicants include heavy metals (HMs), which lea to oxidative stress by the production of reactive oxygen species (ROS). They may cause toxic effects in living organisms by entering through food chain. Brassica juncea plants are hyperaccumulators of heavy metals and possess certain defensive strategies to scavenge the free radicals. The present study deals with the effects of cadmium metal on free radical generation, surface study of leaves and expression of hormones in B. juncea. Response of seedsof B. juncea L. var. RLC-1 were estimated after revealing them to cadmium (Cd) metal stress for 7-days. Treatment of 0.2, 0.4 and 0.6 mM concentration of Cd were given to the seeds. Surface features of leaves, histochemical studies of roots, and hormones profiling had been evaluated in 7-days old seedlings of B. juncea. Scanning electron microscopic (SEM) studies revealed the closure of stomata under Cd induced stress. Additionally, histochemical studies examined by confocal microscopy, showed an increase in oxidative stress and also caused significant damage to nucleus in comparison to control. Alteration in the expression of phytohormones was revealed in LC/MS study. Cd treatment triggered a battery of defence responses in B. juncea plants which included major metabolites.
Keywords: Cadmium stress responses, Brassica juncea L., heavy metals, oxidative stress.