Effect of Rhazya stricta Foliage Leachate on Seedling Growth

and Survival of Some Range Plant Species

Abdulaziz M. Assaeed and Abdullah A. Al-Doss

Dept. of Plant Production, King Saud Univ. P. O. Box 2460

Riyadh 11451, Saudi Arabia



Rhazya stricta, an evergreen poisonous shrub, is rapidly invading large areas of rangelands in Saudi Arabia. A laboratory study was conducted to investigate the effect of its dry foliage leachate on seedling growth and survival of some range plants including R. stricta its self at different stages of seedling growth. Results indicated that seedlings were more susceptible to allelapathic effects at their early days of growth. Seedling growth was depressed and hence survival was negatively affected. Root growth was more restricted than shoots. Species varied in their response to leachate. Sensitivity ranking of species was as follows: R. stricta = Achillea fragrantissima > Farsetia aegyptia > Atriplex halimus > Lasiurus sindicus. Least sensitive species and species having fast and vigorous seedling growth should be selected for revegetation of R. stricta invaded range sites.