Production of nursery-reared seedlings of the gray mangrove <i>Avicennia marina</i> under laboratory conditions

Abstract

Avicennia marina (Forssk.) Vierh. is the exclusive mangrove plant species that is naturally distributed along the Egyptian coast of Gulf of Aqaba, Red Sea. It has the broadest distribution, both latitudinally and longitudinally compared to any other mangrove species. In spite of the fact that mangrove forests usually grow in the intertidal zone, very few species such as Avicennia marina can grow in a truly saline environment. The aim of this study is to investigate germination of A. marina seeds and subsequent growth parameters of their seedlings in response to three different salinity levels composed of tap water, 50 % and 100 % seawater (0, 21, 42 ‰ salinity). Experimental results indicate that 21 ‰ salinity (50% seawater) has the highest germination percentage (%), leaf size (cm2), internode length (cm) and plant height (cm). Moderate germination percentage, leaf morphology and stem growth was recorded for the tapwater treatment. The high salinity treatment of 42 ‰ (100 % seawater) inhibited seed germination. These results could be used in mass production of seedlings and saplings during the process of restoration of this threatened species.

KEY WORDS: germination; leaf morphology; water salinity; Gulf of Aqaba; Red Sea, Sinai.

Egyptian Journal of Botany Vol.5 2003: 55-61