Effect of boron deficiency on photosynthesis and antioxidant responses of young tea plantlets.

Boron (B) deficiency is prevalent in the soils of tea growing regions of India. In order to investigate the physico-chemical alterations associated with B deficiency in tea (( Camellia sinensis (L.) O. Kuntze, cv. T-78) plants, young plantlets were treated with boric acid (HBO) at 0, 2.5, and 5 μM for 8 weeks. B-scarcity decreased the photosynthetic rate ( P), stomatal conductance ( g), and transpiration ( E) alongside chlorophyll a (Chl a), chlorophyll b (Chl b), and carotenoids (Car). Superoxide anion (O), malondialdehyde (MDA), hydrogen peroxide (HO) generation and electrolyte leakage were elevated in B-deprived plants. The activities of ascorbate peroxidase (APX; EC 1.11.1.11), catalase (CAT; EC 1.11.1.6), peroxidase (POD; EC 1.11.1.7), and superoxide dismutase (SOD; EC 1.15.1.1) were increased in B-deficient plants. Simultaneously, transcripts of the antioxidant enzymes were up-regulated under B deficiency. By and large, the results suggest that B deficiency intensifies ROS generation but the antioxidant system does not provide for an adequate protection from oxidative damage. [ABSTRACT FROM AUTHOR]