ABSTRACT
Artemia females can either release encysted embryos by the oviparous pathway or give birth to nauplius larvae by the ovoviviparous pathway. The cysts released from the ovisac are developmentally arrested and can remain in this state for long periods. These cysts are dormant and an endogenous mechanism controls the initiation of development. A fusion of yolk platelets with lysosomes initiates the second phase of yolk degradation. Biochemical and morphological data demonstrate the presence of lysosomal structures in yolk platelets. Yolk degradation is more than a simple mechanism of energy and nutrient supply for the development of dormant cysts. Yolk degradation is an essential step in the cascade of events leading to emergence and proceeds in two phases. In the first phase yolk proteins are solubilized by the internal pH increase of cysts upon development. In the second phase enzymic degradation of yolk takes place.
