Abstract
The effect of seed mass of Acacia ehrenbergiana Hayne on seedling growth and gas exchange activity under glass house conditions was investigated. Seeds were collected from three locations (Al Madinah (24 degrees 89'N, 39 degrees 16'E), Aseer (17 degrees 55' N, 42 degrees 11' E) and Baha (19 degrees 13' N, 41 degrees 80'E) in Saudi Arabia. The seeds were categorized into large, medium and small on the basis of the seed mass. Seeds were sown in potted soil (sand, clay and peat moss, 2:2:1 v/v) for six months. Seedling growth parameters and gas exchange were measured. Seedlings emerged from large seeds exhibited significantly faster growth in terms of shoot and root length and more dry weight, higher RGR (relative growth rate) and greater net photosynthetic and transpiration rates and stomatal conductance than those emerged from medium and small seeds. Leaf number also increased with seed mass but inconsistently.