Accession Number:

AD0603562

Title:

AN INVESTIGATION OF THE MECHANISM OF THE 'CARRY-OVER' PERIOD IN THE PHOTOPERIODIC GONADAL RESPONSE IN BIRDS.

Descriptive Note:

Final scientific rept. for 1 Aug 54-29 Feb 64,

Corporate Author:

WASHINGTON STATE UNIV PULLMAN

Personal Author(s):

Report Date:

1964-07-07

Pagination or Media Count:

11.0

Abstract:

Research on the photoperiodic control of testicular cycles in Zonotrichia leucophrys gambelii showed that when males are subjected to stimulatory daily photoperiods of uniform duration, intensity of light, and quality of light, the rate of testicular growth approximates a logarithmic function of time from resting weight ca. 1 mg. to 250 mg. Within this range, growth as a function of time therefore can be represented approximately as log Wsub t log Wsub o ksub p t in which Wsub o is the resting testicular weight in mg. Wsub t the weight after t days exposure to a daily stimulatory photoperiod of p hours, and k is the testicular growth-rate constant. In this species it was shown that k is a function of light intensity I, wave length lambda, environmental temperature T, the time r elapsed after the end of photorefractoriness, and p. These functions, with the exception of k fr, were estimated sufficiently accurately on the basis of laboratory experiments so that the reliability of the experimental results, projected into natural conditions, can be evaluated.

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE