Interactive effects of low water supply and high salt concentration on the growth and dry matter partitioning of Conocarpus erectus seedlings

Effects of low water supply and high salt concentration and their interactions on the growth of Conocarpus erectus seedlings were studied in a pot experiment at the Research and Experiments Station of King Saud University, Riyadh, Saudi Arabia. Water was applied either every other day or every ten days. Sodium chloride dissolved in water at rate either of three g L-1 or nine g L-1 was applied with watering. Means of stem height, diameter number of branches, number of leaves, total leaf area, average leaf size, leaf dry weight and total dry weight significantly decreased in low water supply and high salt concentrations, with more decreases in the former. Most of these traits decreased more in low water supply when associated with high salt concentration treatment. Below-ground biomass increased in both low water supply and high salt concentration treatments at the expense of above ground biomass similarly. Relative growth rate of the seedlings decreased significantly in low water supply due to concomitant decreases in leaf weight ratio, specific leaf area and consequently in leaf weight ratio. Net assimilation rate did not change due treatments as well as leaf area ratio in high salt concentration treatment.Corresponding Author: Dr. Loutfy I. El-Juhany Plant Production Department, College of Agriculture, King Saud University P. O. Box 2460 Riyadh 11451, Saudi Arabia Tel: 0966-1-4676715 - Fax: 0966-1-4678467 Email: Ljuhany@ksu.edu.s