Absence of successful sexual reproduction of Caulerpa racemosa var. cylindracea in the Adriatic Sea

Abstract

Žuljević A., Antolić B., Nikolić V., Despalatović M. and Cvitković I. 2012. Absence of successful sexual reproduction of Caulerpa racemosa var. cylindracea in the Adriatic Sea. Phycologia 51: 283–286. DOI: 10.2216/11-22.1

Gamete formation and release in Caulerpa racemosa var. cylindracea from the Croatian part of the Adriatic Sea was followed in field and laboratory conditions. During the ten years of research only female gametes were observed. Gamete formation occurred when seawater temperature was above 20°C. Gametes had a distinct eyespot and were 9.3 ± 0.6 µm (mean ± SD, n = 140) long and 3.3 ± 0.3 µm (mean ± SD, n = 135) wide. In situ gamete release started 12–18 min before the sunrise. In Caulerpa, a typically monoecious genus, the production of only one gamete phase in the same thallus is a rare exception. Our observation also differs with previous research of C. racemosa var cylindracea reproduction in Greece where both gametes were found.

Key Words::

• Caulerpa racemosa var. cylindracea
• Sexual reproduction
• Gametes