Understanding the Mechanism of Gamete Release in Sargassum vulgare C. Agardh

Inderdeep Kaur, Reeta Kumari

Environmental Biology Laboratory, Department of Botany, University of Delhi, Delhi, India.
SGTB Khalsa College, Department of Botany, University of Delhi, Delhi, India.

DOI: 10.4236/ajps.2012.39153                

Abstract

Sargassum vulgare C. Agardh shows androgynous receptacles, each bearing on an average 12 unisexual conceptacles which open outside by ostiole, and wherein gametangia (antheridia or oogonia) lie interspersed with paraphyses. Since out-put of eggs is extremely low, 4 - 6 per female conceptacle, Sargassum sp. ensures its survival under all eco-physiological conditions. The released oogonium is “wrapped” in sulphated polysaccharide-rich wall layer known to provide protection against desiccation. Oogonia after being “extruded” out of ostiole, are “incubated” on receptacle, where they grow into eggs that are easily contacted by spermatozoids. Gamete release is synchronous and almost simultaneous ensuring high rates of fertilization. The release occurs on days falling near a full moon or new moon, during low tides when conceptacles lie exposed. Gamete release occurs first from upper conceptacles, which “house” mature gametangia while lower ones are still developing. This results in gamete release over an extended period of time. The zygote dispersal and propagule recruitment also show adaptations selectively advantageous for the alga.

Keywords

Gamete Release; Mesochiton Stalk; Oogonium Incubation; Propagule Dispersal; Sargassum vulgare

Conflicts of Interest

The authors declare no conflicts of interest.

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