Abstract

Plants show morphological and physiological responses to microbial, physical or chemical factors which are known as elicitors. Chitosan is a natural biopolymer modified from chitin, which is the main structural component of squid pens, cell walls of some fungi and crab shells. Water deficit stress is one of the most important abiotic stresses that affects plant physiological and morphological traits. To evaluate the effect of chitosan on morphology and physiology characteristics of sweet basil (Ocimum basilicum) under different irrigation regimes, an experiment was conducted at Shahrekord, south-western Iran. Treatments comprised control, 0.0, 0.2 and 0.4 g/l chitosan applied to plants under normal irrigation, and slight and mild drought stress. Drought stress decreased the content of photosynthetic pigments and growth parameters. Foliar-applied chitosan, in particular 0.4 g/l increased plant growth under stressed or non-stressed conditions compared withuntreated plants. In conclusion, it is suggested that chitosan could be used to reduce the harmful effect of water deficit on the growth of basil plants.