Study of some drought resistance indices in basil (Ocimum basilicum)

A pot experiment in randomized complete blocks design with four treatments in four replications was conducted to study the effect of drought stress and determination of some drought resistance indices in basil (Ocimum basilicum). The irrigation treatments for induction of drought stress were: 100%, 85%, 70% and 55% of field capacity. When the plants had reached the 6 to 8 true-leaf stage, the treatments were imposed and different levels of soil water content were kept at constant level by daily weighting and watering of pots. Leaf water potential, relative water content (RWC), leaf temperature, proline and soluble sugars concentration were measured at flowering stage (5 weeks after irrigation treatments were imposed). According to the results of statistical analysis, different levels of soil water content had significant effect on measured characteristics. As the soil water content decreased, leaf water potential and RWC decreased but leaf temperature, proline and soluble sugars concentration increased. The results of this study showed that basil plant could be able to tolerance the water deficit conditions by stomatal closure and increasing of proline and soluble sugars accumulation (osmotic adjustment).