MORPHO-PHYSIOLOGICAL AND BIOCHEMICAL RESPONSES OF LENTIL CULTIVARS TO DIFFERENT LEVELS OF ARSENIC

Abstract

An experiment was conducted at the Laboratory of Plant Stress Responses, Faculty of Agriculture, Kagawa University, Japan to investigate the morpho-physiological and biochemical responses of four lentil (Lens culinaris Medik.) cultivars viz. BARI Lentil1, BARI Lentil-2, BARI Lentil-5 and BARI Lentil-6 under arsenic (As) stress. Sevenday-old seedlings grown in hydroponic culture were treated with different levels of As

(0 µM, 80 µM, 160 µM, 320 µM as Na 2 HAsO 4 .7H O) for four days. Arsenic treatments reduced plant biomass and water content. Arsenic induced oxidative stress in lentil 2 through the overproduction of reactive oxygen species (ROS) which is indicated by higher malondialdehyde (MDA), other aldehyde, electrolyte leakage (EL) and hydrogen peroxide (H 2 O ) contents. Plant tried to cope up oxidative stress by antioxidant defense mechanisms depending on the cultivars and As doses. Dry weight, 2 fresh weight, shoot length, water content, chlorophyll content, carotenoid content, ascorbate were higher in BARI Lentil-1, BARI Lentil-2 compared to BARI Lentil-5, BARI Lentil-6 at 320 µM As concentration with concomitant reduction in lipid peroxidation (MDA content), other aldehyde, EL, proline, H 2 O content and translocation factor (TF). Activities of antioxidant enzymes-catalase (CAT), dehydroascorbate reductase (DHAR), glutathione peroxidase (GPX) were decreased while monodehydroascorbate reductase (MDHAR), glutathione reductase (GR), superoxide dismutase (SOD) activity were increased in BARI Lentil-5, BARI Lentil-6 compared to BARI Lentil-1, BARI Lentil-2. Considering the morpho-physiological parameters and antioxidant metabolism, BARI Lentil-1 and BARI Lentil-2 could be recommended as relatively As tolerant over BARI Lentil-5, BARI Lentil-6.