The Herpetological Journal

pp.125-132

Authors: Francisco J. Saez, Benito Fraile, Mary Paz De Miguel And Ricardo Paniagua

Abstract: The response of the different germ cell types and glandular tissue of the testis to low temperatures (4°C) and long photoperiods ( 16L:8D) was studied in the marbled newt (Triturus marmoratus) by histologic quantitative methods in the three periods of the annual cycle: quiescence (January-March), germ cell proliferation up to round spermatids (April-June), and spermiogenesis (July-September). Together with each group of cold-exposed newts, another group was maintained at mild temperature (20°C) over the same long photoperiod. At the beginning and end of each period, initial and final wild controls were collected. In the quiescent period, only spermatogonial proliferation was observed in the initial and final controls as well as in the cold-exposed newts. The newts kept at 20°C developed spermatogenesis up to the round spermatid level. At the end of the germ cell proliferation period, the final controls showed round spermatids; the newts exposed to 20°C developed complete spermatogenesis; and the newts maintained at 4°C only presented spermatogonial proliferati_on. At the end of the spermiogenesis period, the final controls and the newts kept at 20°C showed complete spermatogenesis and developed glandular tissue whereas the newts exposed to 4°C only had round spermatids and had no glandular tissue. Present results suggest that although low temperature does not affect spermatogonium proliferation it impedes both the subsequent steps in spermatogenesis and the development of glandular tissue.