Accession Number : AD0693007

Title :   TRANSPIRATION OF UPPER AND LOWER SURFACES OF A LEAF AT VARIOUS ORIENTATIONS IN THE EARTH'S GRAVITATIONAL FIELD,

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : Kotlyar,V. Z. ; Lyubynskyi,M. A.

Report Date : 09 JUN 1969

Pagination or Media Count : 9

Abstract : Changes were noted in the transpiration of the upper and lower surfaces of a leaf rotated so the surfaces are 180 degrees from their natural orientation with respect to the earth's gravitational field. Undetached sugar beet leaves were used in the study. When the morphologically lower side of the leaf blade is turned up, its transpiration rate increases rapidly, while the rate for the upper side of the leaf (now in the underneath position) is reduced. The ratio of the upper/lower leaf transpiration is lowered. On returning to its natural position, transpiration of the lower leaf drops and then increases somewhat. Thus, when the leaf is rotated so the gravity vector 'enters' the lower epidermis, transpiration through the upper epidermis is inhibited by the effect of the gravitation field. According to the proposed mechanism for this reaction, when the orientation of the leaf with respect to the gravitational field is changed, the cells regulate the water vapor diffusion process of the stoma breathing cavity differently than when the leaf is in its natural position. (Author)

Descriptors :   (*PLANTS(BOTANY), *EVAPOTRANSPIRATION), METABOLISM, GRAVITY, PLANT TISSUE, WATER VAPOR, DIFFUSION, PHYSIOLOGY, SURFACES, USSR

Subject Categories : Anatomy and Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE