Histological study of two sponge species with and without spicules in class Demospongiae

Despite broad biological knowledge, the data on the role of reproduction in the structuring and maintenance of sponge population is limited. In this regard, the present investigation carried out to compare the histological structure of two sponge species with spicule (Ircinia strobilina Lamarck, 1816) and without spicule (Haliclona simulans Johnston, 1842). Sampling was conducted by diving in artificial reefs (12m depth) in Bahrakan (located in the north of Persian Gulf) using Scuba method. The samples were firstly studied macroscopically and systematically. The samples were then fixed in 70% methanol and then were run through an alcohols and xylene sequence and finally were embedded in paraffin. 5 µm thick tissue sections were prepared using rotary microtome and were stained with Hematoxiline-Fuchsin. Tissue sections were studied using light microscope. Finally, the order of sponge was identified using the kind of water canal system. It should be noted the elasticity property of sponge species, spicules presence or absence in samples, existence or lack of a spongin fibers throughout the tissue structure, were emphasized the sponge species. Moreover, maximum size of reproductive cells and their density in studied species were observed in autumn and winter (reproductive season of these species). In addition, some cell types, such as sclerocytes have only been observed in species with spicules that with regard to the role of these cells in spicule production, their existence and density in speculated species was logical.