IS PH(I) A FACTOR FOR DORMANCY IN FRESH-WATER FAIRY SHRIMPS

Cellular dormancy is a common event in the life cycle of lower crustaceans, especially in brine shrimps and fairy shrimps. We have studied termination as well as initiation of cellular dormancy in the cryptobiotic cysts of a freshwater fairy shrimp Streptocephalus dichotomus by elevating the internal pH optima of the cysts. Experimental evidences clearly indicate that alkalinization had no significant effect on the termination of dormancy, but subsequently no hatching occurred. Thus the dehydrated gastrula, containing approximately 4000 cells, undergoes dormancy with environmental adversity combined with physiological status of the growing embryo. The cysts of fairy shrimps, thus, do not come under the category of either aerobic or anaerobic dormancy as described for the brine shrimp Artemia sp.