A pot experiment was conducted during the two successive seasons of 2018/2019 and 2019/2020 at west of Somosta, Beni-Suef governorate, Egypt, to explore the effect of both saline water and foliar application of chitosan treatments on growth parameters for vegetative and flowering and on some chemical constituents of Calendula officinalis L.
In contrast to control plants which were irrigated with tap water, the plants were irrigated with saline water containing NaCl at concentrations of 1000, 2000, 3000, 4000 and 5000 ppm. They were treated also by chitosan as foliar spray application at 100, 200 and 400 ppm, as well as, the interaction between them were involved. The higher salinity levels (4000 and 5000 ppm NaCl) caused significant decreases in all vegetative and flowering growth measurements of pot marigold plants compared to control. Maximum reduction was observed at 5000 ppm NaCl which showed higher increase of the free proline content, sodium and chloride percentages. Meanwhile, the increase in the concentration of salt in the irrigation water resulted in a decrease in the total chlorophylls in leaves and carotene content in flowers. Foliar application of chitosan at concentrations 200 and 400 ppm alleviated the adverse effect of salinity condition thereby vegetative, flowering characters and also chemical constituents were improved. The best level of foliar application of chitosan was at 400 ppm Whereas, non-significant effects were found on the vegetative and floral parameters and some chemical components as a result of the interaction between both aspects studied in comparison with untreated treatment.