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Translocation of Fats as Such in Germinating Fatty Seeds
J. B. Rhine
Vol. 82, No. 2 (Oct., 1926), pp. 154-169
Published by: The University of Chicago Press
Stable URL: http://www.jstor.org/stable/2470942
Page Count: 16
You can always find the topics here!Topics: Fats, Seedlings, Hypocotyls, Fatty acids, Plants, Sugars, Peas, Seeds, Respiratory quotient, Starches
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1. It was found, as Schmidt had reported, that liquid fats would rise in the intercellular spaces of etiolated pea seedlings and would enter the cell. Contrary to Schmidt, however, it was found that neutral fats rose more rapidly than free acids in certain oils, and furthermore that neutral fats entered the cells from the intercellular spaces. Schmidt's theory of fat intake was thus shown to be incorrect. 2. It was shown that while the liquid fats pass into the cell from the intercellular spaces of the pea, this cannot be taken as analogous to the situation existing in plants in which fats have been thought to move from cell to cell. It was shown that the intake of the fat was due to a water deficit in the walls of the starved etiolated pea seedlings, when they were exposed to unsaturated air, and that when well supplied with moisture in air and soil they would not allow either the rise or intake of oils. 3. Schmidt's report that the endosperms of fatty seeds did not have sugar during germination was found to be incorrect, and, therefore, this evidence is not admissible in support of fat movement in plants. 4. The presence of oils of similar composition in the new tissue and the old was shown to be of no significance in this connection, since the same condition prevails with respect to starch in starchy seedlings. 5. Schmidt's theory of "soaplike" linkages forming and aiding in fat movement is shown to be untenable, in view of the PH values found in the seedlings investigated. This point also covers the question of movement of fatty acids as soaps, making the existence of soaps in the cell seem impossible. 6. By determining the respiratory quotients on hypocotyls of fatty and of starchy seeds during germination, evidence was obtained that the fatty seed hypocotyls were being furnished carbon in the same state of reduction as were those of the starchy seeds. The logical inference is that that form could not be fat. 7. If fats were to move as such a gradient of decreasing concentration might be found in the region of most active growth. The contrary is the case, both microscopical and quantitative data showing that a steep gradient exists in the opposite direction, increasing with approach toward the tip of the hypocotyl. 8. Cell walls in tissues through which the fats have been thought by some to pass, and in which fatty droplets may be found, have been examined for fats "en route." No evidence of such movement was found. 9. Since the oils would have to pass downward through several centimeters of denser viscous medium, to say nothing of the admitted impenetrability to oil of the water saturated cellulose membrane, the fat movement theory, from the standpoint of the physics involved, would have to be given up, at least until some good positive evidence that such movement can and does occur is presented. 10. All evidence in favor of fat movement in plants that has been considered and reinvestigated has been found incorrect in fact or interpretation. The further evidence bearing on the problem, presented in this paper, favors the view that all the fat stored in the fatty seed is, as we have known most of it to be, first converted to sugars before being transported.
Botanical Gazette © 1926 The University of Chicago Press