Responses of Kyllinga peruviana Lam. to Sea Water Spray

摘要

Response of Kyllinga peruviana Lam. to salt spray was studied to have an insight into the ecophysiological adaptations underlying the responses. Plants were exposed to foliar salt spray at: two sprays per week (2SS), four sprays per week (4SS) or six sprays per week (6SS), while those sprayed with de-ionized water served as control (CSS). Salt spray did not affect plant survival but had negative effect on growth. The growth parameters decreased except stem girth, which increased significantly in plants sprayed with seawater. Fresh and dry mass of plant parts were significantly lower under seawater treatment than in control. Total biomass, the relative growth rate and leaf total chlorophyll decreased while the root: shoot ratio increased under seawater application. Air-borne salt reduced plant xylem water potential but increased stem succulence for ion dilution. Salt spray accumulated Na+ and Cl- in the aerial parts, resulting in an increased total nutrient and percentage ash content, which culminated in ion toxicity. Salt spray reduced uptake of some essential nutrients but increased N in the aerial parts of seawater-treated plants showing the presence of salt-related nitrogen compounds for osmotic adjustment. Significantly higher values were obtained for Na: K in plants exposed to salt spray than in the control. It led to reduction in stomata density and number of stomata per leaf by as much as 42.86% and 80.42% respectively at 6SS. Air-borne salt caused necrotic damage on the leaf with increasing application level. Generally, salt spray had no effect on the root growth. Kyllinga peruviana tolerates sea water spray by the development of some adaptations to withstand salt-related stress associated with the strandline environment.