ИСТИНА

Maintaining of invertebrates in culture allows to carry out many types of research that appear unavailable in natural conditions. Cultures of Aurelia sp. (Cnidaria, Scyphozoa) polyps exhibit the dependence between long-term temperature conditions and the sensitivity to the temperature shift inducing strobilation. Polyps, which were kept at unstable temperatures above 20°C, require specific conditions for a long time or chemical agents for the induction of strobilation. The maintenance at the constant temperatures below 20°C for a year or more leads to the ability of polyps to strobilate in response to small short-term temperature drop. A sharp increase of salinity induces abnormal strobilation in Cassiopea sp. (Cnidaria, Scyphozoa) polyps. Duration of strobilation in Scyphozoa is inversely related to the temperature of strobilation and independent of the temperature of the induction of strobilation. The culture of Sycon sp. (Porifera, Calcarea) have been maintained in an aquarium with other invertebrates in natural sea water for many years. It allows to find out some factors effecting growth and development of Sycon sp. Sponge growth rate depends not only on organic nutrients, but also on regular administration of depleted inorganic salts. Change of the sodium chloride relative concentration in seawater initiates gametes production in adult sponges. In lack of organic compounds (milk or carbonic acid diamide and sodium phosphate in different trials) sponge formes asconoid structure only, but not syconoid structures. Change of the sponge body position in relation to the water current leads to additional osculum formation.