Boron induced changes in biochemical constituents, enzymatic activities, and growth performance of wheat

The present study investigates how excess boron (B) affects and alters the biochemical constituents and enzymatic activities of wheat ( Triticum aestivum var. ‘Raj 4037’), consequently leading to reduced plant growth and yield. Plants were raised in soils supplemented with various concentrations of B (0, 1, 2, 4, 8, 16, and 32 µg B g −1 soil). Biochemical constituents including soluble leaf protein contents, total phenol contents, soluble sugar contents, proline contents, enzymatic activities of peroxidase (POX), and nitrate reductase (NR) were analyzed. In addition, growth parameters namely shoot–root length, shoot–root fresh and dry weight, seed number and seed weight were analyzed to assess the impact of B toxicity. Results indicate that change in biochemical constituents were correlated with B treatments. Boron concentrations beyond 4 µg g −1 significantly increased soluble leaf protein contents, total phenol contents, soluble sugar contents, and proline contents. The POX activity was found to be positively correlated with B treatments. B significantly affects nitrogen metabolism and nitrate accumulation which is reflected by the downregulation of NR activity at higher B concentrations. B induced changes in physiological parameters of the plant which subsequently led to the reduction in growth, biomass production, and yield attributes. Out of the various concentrations of B, 8 µg g −1 was moderately toxic while 16 and 32 µg g −1 generated high toxicity and induced B stress response to confer tolerance in wheat. Further, a possible mechanism of B toxicity response in wheat is suggested.