In vitro biochemical evaluation of cadmium tolerance mechanism in callus and seedlings of Brassica juncea

Abstract

In vitro grown callus and seedlings of Brassica juncea were treated with equimolar concentrations of cadmium and compared for their respective tolerance to cadmium. Calli cultures were grown on Murashige and Skoog medium supplemented with alpha 6-benzyl aminopurine (200 microg (-1), naphthalene acetic acid 200 microg L(-1)) and 2,4-dichloro-phenoxy acetic acid (65 microg L(-1)) while the seedlings grown on Hoagland's nutrient solution have been carried out. Cellular homeostasis and detoxification to cadmium in B. juncea were studied by analyzing the growth in terms of fresh weight and dry weight, lipid peroxidation, proline accumulation, and antioxidative enzymes (superoxide dismutase (SOD), ascorbate peroxidase (APX), and catalase (CAT)). At 200 microM cadmium, callus and seedlings showed 73.61% and 74.76% reduction in tolerance, respectively. A significant increase in malondialdehyde (MDA) content was found in both calli and seedlings; however, the amount of MDA content was more in seedlings. Proline content increased on lower concentration of cadmium (up to 50 microM), and it further decreased (up to 200 microM). But the accumulation of proline was higher in callus cultures. The overall activity of antioxidative enzymes (SOD, CAT, and APX) was found to be higher in callus in comparison to seedlings of B. juncea. Callus and seedlings showed a significant (P <or= 0.5) increase in SOD activity in a concentration-dependent manner up to 50 microM cadmium concentration but decreased further. APX activity increased significantly at low cadmium levels but CAT activity decreased significantly throughout on increasing cadmium concentrations from 5 to 200 microM, respectively. Hence, it was observed that callus of B. juncea was more tolerant in comparison to seedlings exposed to equimolar concentrations of cadmium. Thus, from the present studies, it is concluded that calli were more tolerant toward cadmium-induced oxidative stress. Hence, it is suitable material for the study of cadmium tolerance mechanisms and for the manipulations within them for better understanding of cadmium detoxification strategies in B. juncea.

In vitro Study of Interactive Effect of Cadmium and Salicylic Acid on Growth and Biochemical Parameters in Tetra and Hexaploid Wheat

“…Thus this reduction might be accompanied by the accumulation of H2O2 in different compartments which may cause the inactivation of this enzyme (Vitoria et al, 2001). Similar trends in the SOD activity under Cd stress had been observed in Sesbania drummondi callus (Israr et al, 2006), B. juncea callus (Shekhawat et al, 2010) and the adapted calli of sunflower and safflower (Gallego et al, 2002;Namjooyan et al, 2012). Catalase (CAT) is another integral component of antioxidant system and its role in protecting the organism from damage caused by ROS is indispensable.…”

“…Tissue culture techniques offer valuable tool for studying, testing, improving and selecting plant material for tolerance to stress factors and cellular stress response (Azevedo et al, 2005;Shekhawat et al, 2010;Ahmad et al, 2013). This evaluation of the behaviour of in vitro cell cultures exposed to Cd toxicity may contribute to the knowledge that these cells may used in genetic improvement programs to withstand Cd toxicity.…”

Alleviation of exogenous oligochitosan on wheat seedlings growth under salt stress

“…Each value represents the mean±SE. Control plants were grown on Hoagland's nutrient solution as control, NaCl plants were stressed by 150 mM NaCl, oligochitosan plants were pretreated with 0.0625% oligochitosan solutions, oligochitosan-NaCl plants were pretreated with 0.0625% oligochitosan and then stressed by 150 mM NaCl for encoding SOD (Bowler et al 1992;Shekhawat et al 2010). Higher activity of SOD is an indication of efficient detoxification of superoxide radical (Abraham and Dhar 2010).…”

Calcium supplementation modulates arsenic-induced alterations and augments arsenic accumulation in callus cultures of Indian mustard (Brassica juncea (L.) Czern.)

“…In a recent study, comparative evaluation of cadmium (Cd) tolerance mechanisms was performed in callus and seedlings of B. juncea. The study found calli to be more tolerant to Cd-induced oxidative stress (Shekhawat et al 2010). Yang et al (2007) evaluated As accumulation and responses in calli of Pteris vittata and Arabidopsis thaliana and reported that P. vittata calli accumulated more As, tolerated higher AsV concentrations, and showed lower toxicity as compared with the calli of A. thaliana.…”