effects of thiamine spraying on biochemical and morphological traits of basil plants under greenhouse conditions

Thiamine, as a co-enzyme required to develop many of the metabolic reactions, plays an important role in regulating growth and reducing the effects of environmental stresses on plants. in this project the effect of thiamin (thi) applied as foliar spray on some morphological and physiological traits was investigated in basil (ocimum basilicum l.). four levels of thi including 0 (distilled water), 250, 500 and 750 μm were tested in a randomized complete design with three replications at research greenhouse of university of guilan, iran. the results show that thi application exerted a significant effect on the most studied indices. the amounts of leaf, stem and root dry weights in thi-treated plants was more than control. thousand grain weight increased by an increase in thi concentration, as, its value in 700 μm thi, was 26% more than control. thi spraying especially in the concentration of 750 μm improved the leaf nutrients content (n, p and ca). chlorophyll b content in leaves affected positively by thi, and its highest value obtained in 750 μm treatment. the highest and the lowest phenolic compounds were gained in 0 and 750 μm levels of thi, respectively. a similar trend was observed for total antioxidants, where their content in 750 μm was 13% more than control treatment. generally, it seems that thi can be considered as an appropriate growth regulator in basil medicinal plant cultivation.