CYTOLOGIC VARIATION IN THE PINEAL ORGAN OF ROSERINGED PARAKEETS (PSITTACULA-KRAMERI) WITH RESPECT TO ARTIFICIAL PHOTOPERIODS AND ANNUAL CYCLICITY IN TESTICULAR FUNCTIONS

Adult male roseringed parakeets were transferred to 16L : 8D (LP), or 8L : 16D (SP) for 45 or 90 days on four particular dates corresponding to the different phases of an annual testicular cycle and the cytolog ical responses of the pineal were studied comparing them with the feat ures in respective natural photoperiodic (NP) birds. Different cytolog ical characteristics including the values of nuclear diameter in pinea locytes indicated that LP for 45 days during the pre-breeding phase an d for 90 days during each phase resulted in an increased pineal activi ty, while SP for 45 and 90 days induced inhibitory responses of the pi neal during each, but not the progressive phase of the annual testicul ar cycle. During the latter phase, none of the artificial photoperiodi c schedules, other than LP for 90 days, influenced the cytological fea tures of the pineal. The results suggest that the photosensitivity of the pineal in these parakeets varies in relation to the testicular fun ctions in an annual testicular cycle, but the seasonal pattern of phot operiodic response of the pineal and that of the previously studied te stes in the same birds does not seem to be identical.