Abstract
Morphogenesis of different-shaped biogenic crystals presents one of the important biomineralization problems. Growth of various calcitic spicules from Sycon sp. have been studied by using calcein marking. We found that spicule production is dependent on various conditions such as location in the sponge body and illumination, whereas the calcification rate by the spicule-forming cells is constant. Morphological, crystallographic and fluorescence analyses have enabled the investigation of the growth patterns of the different spicule types. We suggest that different mechanisms are involved in the growth of various spicule types. Triradiate spicules are deposited from the centre towards the rays. Crystallographically different rays of the triradiates differ in the dynamics of formation as well. Slender monaxon spicules are deposited very fast (more than 65 $\mu $m/h). Two calcification sites are involved in the secretion of curved monaxon spicules. These spicules grow unidirectionally from one extremity at a rate of 12.0 $\mu $m/h, and are thickened at some distance from the necleation site. Possible mechanisms that may account for the observed growth patterns are discussed.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Proceedings of the Royal Society of London. Series B: Biological Sciences
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
