Effect of bio-elicitor chitosan on physiological and morphological properties in purpule basil (Ocimum basilicum L.) under water deficit

Medicinal plants have different reactions to drought stress in yield and production. Ocimum basilicum L. as a medicinal plants, used in the treatment of many diseases. Chitosan, a major component of the cell wall of fungal species, causes physiological and morphological changes in the plant. This study aimed to evaluate the effects water stress (100, 60 and 30% field capacity) and elicitor chitosan (0, 0.2 and 0.4 grams per liter) on growth and development properties of basil, in the research farm of Islamic Azad University, Shahrekord Branch in spring 2014. Experimental treatments were arranged as factorial in a complete randomized design with three replications. The morphological (plant height, inflorescence, number of branches, leaf area, fresh and dry weights) and physiological parameters (chlorophyll, carotenoids, proline, soluble carbohydrates, total phenolic and flavenoides) studied. Analysis of variance showed that drought stress and chitosan had significant effects on some of morphology and physiology characteristics. Drought stress decreased the content of photosynthetic pigments, leaf area, plant height, fresh and dry weights of root and arial parts and increased proline, soluble carbohydrates, total phenol and flavenoides. Treatment with chitosan increased fresh and dry weights of root and arial parts, soluble carbohydrates, proline, phenol and flavonoid in stressed and non-stressed plants. Since drought is a distinguishing feature of Iran and there is no escape from this natural and unchangeable phenomenon, therefore, in order to combat and reduce damage water shortage, the use of bio-polymer chitosan as a natural material reducing stress in basil, is important.