Towards a prospective transplantation of the local mangrove avicennia marina (forssk.) Vierh. Growing on coast of qatar i. Ecophysiological performance of juveniles.

Abstract

A population sample of propagules was collected at random from average size A. marina trees growing at "Dhakhira" (Qatar). This sample was then divided into subsamples which were used to detect the effects of light intensity, salinity and pretreatment of propagules on their survivorship and on the different growth parameters of produced seedlings. The higher radiation intensity (HRI) results in, on the average, lower survivorship of seedlings compared to those growing under lower radiation intensity (LRI). The highest survivorship is that for seedlings growing at lower salinity level under LRI. However, when growing on soil substrates at high salinity levels, higher survivorship results under HRI associated with much higher growth measures compared to those attained under LRI. Growth of seedlings under LRI and low salinity level is characterised by higher biomass and ash contents, and lower root ratio that results in larger number of leaves and of their total area associated with lower SLA and LAR. Consequently, the highest relative growth rate is attained for seedlings of this latter treament. It is concluded that salinity level and radiation intensity have determinant effects on seedling growth so that proportional levels of these factors result in higher survivorship and growth. However, growth under LRI and low salinity, although have the highest survivorship, yet further investigation is necessary to test the effect of imposing salinity stress prior to transplantation.