TRANSPIRATION AND THE ABSORPTION OF MINERAL SALTS

Abstract

The effect of varying rates of transpiration upon the absorption of mineral salts is an old question that has been studied by numerous investigators. No attempt will be made here to review these bulky data. Earlier opinions, as summarized by Curtis (2), were usually in favor of increased absorption of mineral salts. More recent studies by various investigators are characterized by a decided lack of unanimity of opinion. The work of Hasselbring (7), Kiesselbach (9), Muenscher (12), Mendiola (10) and others indicates that different rates of transpiration are without effect upon the absorption of mineral salts. Investigations conducted by Hass and Reed (6), Hitchcock and Zimmerman (8), and Freeland (3, 4) support the contention that transpiration is a factor which affects the absorption and translocation of mineral salts. The confusion that exists in this field of investigation is probably caused largely by the failure to eliminate all other factors in the metabolism of the plant, which may affect the absorption of mineral salts. It is the purpose of this paper to present a technique that will predominantly keep these other contributing factors constant, and, with such controlled conditions, to demonstrate that different rates of transpiration are accompanied by corresponding rates in the absorption of certain anions and cations.