The effects of carbon dioxide concentrations on some morphological and physiological characteristics of ligustrum vulgare

Carbon dioxide is one of the most important necessary factors for plant growth. In order to study morphological and physiological response of ligustrum vulgare to Co2 enrichment, one-year-old seedlings of this species exposed to different carbon dioxide concentrations for two months. Treatments included 450 (control), 750, and 1100 ppm Co2. The experiment was based on a completely randomized design with three replications. Then some morphological and physiological characteristics were measured. Results showed Co2 concentrations of 750 and 1100 ppm increased all morphological traits (except collar diameter and root dry weight) and physiological characteristics such as proline, chlorophyll a and nitrogen. The highest amounts of proline, chlorophyll a and nitrogen were observed at concentration of 750 ppm. The amount of increase in proline was about 4-fold compared to the control. The study concludes that the increased carbon dioxide concentration in the future maybe improve the growth of this plant.