Aspects of spore production in the red algaCeramium

Abstract

Tetraspore development from the post-meiotic to the mature stage has been studied using light and electron microscopy and histochemistry. The structure of the mature carpospore is identical to that of the tetraspore suggesting a similar developmental sequence. The tetrasporangial wall consists of 3 main fibrillar layers, the origin of the inner of which appears to be the wall-plasmalemma interface. The development of furrows cleaving the protoplast into 4 results in the formation of new plasmalemma and subsequently new wall fibrils. The Golgi apparatus is important in the formation of two well-defined substances. The first is fibrillar and is secretedvia vacuole-like structures into the sporangial wall. After spore release, this functions as a protective mucilaginous layer. The second has a distinctive fine structural morphology and probably functions as an adhesive. Observations on spore releasein vivo reveals a similar process for both types of spore. Each spore is surrounded by mucilage which may assist in initial attachment prior to the secretion of the adhesive.