UPWARD MOVEMENT OF INORGANIC SOLUTES AS AFFECTED BY A GIRDLE

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Abstract
Shoots from each of 10 trees and shrubs were selected in groups of 3, 1 of these girdled, 1 removed at the time of girdling, and the 3d removed at the time the girdled shoot was removed. The difference in ash and N contents between shoots indicates the amt. of each material which passed the girdle; the difference between the 1st and 3d shoots indicates the effect which the girdle through its influence on the xylem imposes on the upward movement of the transpiration stream and its salts. The data show: 1) a considerable amount of both ash and N passed the girdle, thus further establishing the generalization that the upward movement of inorganic solutes takes place chiefly in the xylem; 2) the influence of the girdle is somewhat characteristic of the species and of the environment in which the plant is growing. The effect of the girdle appears to be detd. largely by the abundance, size, and distr. of tracheae in the annual rings of xylem. When the plants are arranged from diffused-porous to ring-porous, and this arrangement correlated with the amt. of ash ranging from larger to smaller amts. which passed the girdle of each plant, the 2 series are the same. The girdle, as a break in the continuity of the phloem, apparently does not influence the upward movement of salts; but the girdle, as it affects the movement of water, influences the upward movement of salts in the xylem.