Stress tolerance in cabbage

B. K. Singh, S. R. Sharma, Chandra Prakash, R. N. Barwal and M. R. Dhiman

ICAR News: A Science and Technology Newsletter 17 (2): 2-3, 2011

E-mail: bksinghkushinagar@yahoo.co.in

            Production of deleterious reactive oxygen species (ROS) such as singlet oxygen (¹O₂), superoxide radical (^●O^-₂), hydrogen peroxide (H₂O₂), hydroxyl ion (OH^-) and free hydroxyl radical (^●OH) is one of the reasons for poor productivity and quality of the harvest under stressful conditions in cabbage. Plants possess well-developed defense systems against deleterious ROSs by limiting their formation and by triggering for their removal. If ROSs are not neutralized, they damage cells, causing susceptibility to biotic and abiotic stresses, yellowing and senescence. Pre-mature senescence leads to loss of vigour, productivity and quality of produce. Antioxidant enzymes- superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT)- have touted as beneficial for mitigating effects of oxidative stresses induced by ROSs. SOD, localized in cytosol, chloroplast, mitochondria and peroxisomes, accelerates the dismutation of ^●O₂^- to H₂O₂. POX, an iron heme protein, catalyses H₂O₂ reduction with a concurrent oxidation of a substrate, mostly located in cell wall, and is involved in the oxidation of phenol compounds towards lignin synthesis. CAT also catalyses H₂O₂ reduction to water and molecular oxygen, and is localized in mitochondria and peroxisomes, and absent in chloroplast. This study determined variability for enzymes SOD, POX and CAT activities, and their inheritance was studied in the cabbage samples harvested at the fresh marketable stage, frozen immediately in liquid nitrogen and placed at -80 ⁰C for assay. Enzymatic antioxidant activities showed 1.6, 12.8, and 18.2-fold difference for SOD, POX and CAT, respectively. Red Cabbage, 83-2, KIRC-1-1, ARU Glory, Kinner Red, MR-1, AC-208, Red Rock Mammoth, KIRC-8 and KIRC-1A showed higher activity of antioxidant enzymes. All enzymatic antioxidants expressed high heritability along with low genetic advance as percentage of mean indicated the predominance of non-additive genes, and provide good prospects for hybridization and hybrid breeding. The results indicate that breeding of antioxidant potential cultivars will enhance the stress tolerance ability of cabbage and will result in healthy plant stand, and thus eventually mitigate climate change effects in cabbage cultivation.