Kinetin modulates physiological and biochemical attributes of Vigna radiata L. seedlings exposed to 2-benzoxazolinone stress

Abstract

Cytokinins are growth regulators concerned with influencing numerous plant metabolic and stress adaptive mechanisms under adversity. The present investigation was conducted to study the role of kinetin (KN) in ameliorating the damaging effects of allelochemical 2-benzoxazolinone (BOA) on Vigna radiata seedlings. The experiment was undertaken in sand culture under glasshouse conditions where plants were exposed to BOA (1 and 1.5 mM) by root and KN (1 mM) foliarly and then sampled for different growth parameters. BOA at both concentrations induced growth retardation which was more pronounced at the higher dose (1.5 mM). BOA toxicity gradually decreased photosynthetic pigment, relative water, protein, anthocyanin content, nitrate reductase activity and antioxidant enzyme activity. On contrary, enhanced electrolyte leakage (EL), lipid peroxidation (LP), hydrogen peroxide (H2O2), proline content and phenylalanine ammonia lyase activity (PAL). The foliar KN supplementation assisted in growth restoration by influencing several physiobiochemical attributes. KN-induced growth amelioration was reflected as reduced generation of reactive oxygen species and membrane stability with reduced LP and EL. The seedlings exposed to combined BOA and KN treatment exhibited higher antioxidant enzyme activity and total phenolic content (TPC) coupled with proline accumulation which play significant role in combating stress efficiently. The results revealed that KN has potential to buttress the defence system of crops grown in soil having higher BOA content. In future, research emphasis should be given on gene regulation mechanisms by allelopathins in plant system.