Showing papers by "Heidelberg University (Ohio) published in 1943"

The enzymatic and vitagen properties of unsaturated fats as they influence the differentiation of certain plant tissues

Abstract: AS A continuation of earlier work by the author, the present paper elaborates upon the internal distribution of unsaturated fats and associated enzymes in relation to the differentiation of certain types of plant cells. The formation and deposition of unsaturated fats are predominantly localized in the epidermis, hypodermis, endodermis, mestome or bundle sheath, trabecular cells and integument cells, all of which are essentially dermal structures. Certain characteristic physico-chemical relations in and near these dermal structures evidently underlie their structural differentiation. Special consideration is given to the reactions which determine whether or not an endodermis is formed. Incidental reference is made to the functional role of the endodermis. Preliminary work on certain vitamins as they influence the vitagen (Rosenberg, 1942) action of unsaturated fats in the development of some tissues is reported. GENERAL NATURE AND DETECTION OF THE FAT SYSTEM IN DERMAL TISSUES.-It is generally recognized that unsaturated fats have a tendency to oxidize. Several workers have demonstrated that this oxidation may be accelerated by an unsaturated fat oxidase system (Tauber, 1940; Strain, 1941; and Van Fleet, 1942b, 1943). The rate of oxidation of fats may be influenced by the hydrion concentration and by various pro-oxidants and antioxidants (Bradway and Mattill, 1934; Olcott and Mattill, 1936; and Van Fleet, 1942b). For a complete description of the exact mechanism of fat oxidation in plant tissue see Van Fleet, 1942b. The oxidation system in dermal tissues may be detected by application of buffered alkaline solutions (pH 7.8-8.2) and suitable indicators to fresh or frozen freehand or sliding microtome sections. The indicators found to be best adapted to this work are guaiacol, the reduced or leuco form of thionin, leuco methylene blue, leuco indigo carmine, leuco cresyl blue, "Nadi" and "Dopa." Through the application of alkali, particularly sodium selenite (Van Fleet, 1942b, 1943), the unsaturated fats are freed from inhibitols so that immediate oxidation takes place, and at the same time oxidation in other surrounding tissues is held in an inactivated state by the alkali. The term inhibitol is used here to denote all naturally occurring substances that are alkali-labile and related to a-tocopherol (Golumbic, 1941) or other possible unknown vitamin or related substances (see Mattill and co-workers). The term antioxidant signifies all artificially introduced or naturally occur-