Salt spray as a micro-environmental factor affecting the growth of Commelina maritima L. at Lekki Beach, Nigeria

Commelina maritima L. is a dominant perennial halophyte that is restricted to sandy beaches where it plays major ecological roles in Southern Nigeria. This study examines the response of this plant to saltwater sprays, a factor that affects the growth of coastal plants. Plants were sprayed with seawater twice per week (2/week), four times per week (4/week) or six times per week (6/week) while control was sprayed without seawater (de-mineralized water) six times per week (0/wk). Survival, growth and biomass allocation of the plants were determined. Salt spray did not affect plant survival but significantly (p≤0.05) decreased number of leaves, shoot length, stem girth, leaf area and root growth. Relative growth rate and number of branches were not significantly (p≥0.05) affected by salt spray. Sea spray significantly (p≤0.05) reduced fresh and dry mass of plant parts, total biomass and leaf total chlorophyll when compared with the control. Root : shoot ratio increased significantly (p≤0.05) under seawater treatment as the shoot growth was more negatively affected than root growth. Relatively more biomass was allocated to the root than shoot in seawater-treated plants. Salt spray increased shoot ash content and negatively affected plant organic content. C. maritima can be classified as a salt spraysensitive plant. Salt spray is a micro-environmental factor affecting its survival and growth, thus influencing its distribution in strandline.