Effect of chitosan on morpho-physiological traits and regeneration of Iris pseudacorus plantlets under in vitro conditions

Iris pseudacorus is a highly valuable ornamental and medicinal plant. Chitin is one of the most abundant polysaccharides in nature and is widely used in agriculture for seed germination to stimulate plant growth. Chitosan can be used as an antibacterial component and can increase plant resistance to diseases. This study was conducted based on a completely randomized design. Treatments consisted of different concentrations of chitosan (0, 5, 10, 20, 40, 80, and 120 ppm) with five replications. Morphological and physiological traits including leaf number, leaf weight, plantlets height, leaf area, percentage of regeneration, chlorophyll a, b and total, total phenol, and flavonoids were evaluated. Results of the analysis of variance showed that chitosan significantly affected leaf number, regeneration percentage, phenol content, and leaf fresh weight. Flavonoids, chlorophyll a and b, total chlorophyll were also significantly affected. Results also showed that the highest (31.60 mg/g gallic acid) and lowest (15.51 mg/g gallic acid) total phenol content was obtained from 120 ppm chitosan and control samples, respectively. The highest flavonoid content (5.78 mM/g) was obtained by 120 ppm chitosan and the lowest value (3.20 mM/g) was recorded in the control treatment. In general, our investigation showed that chitosan had a positive effect on all measured traits. In most of the measured traits, the best chitosan concentration was 120 ppm.