Foliar applications of nutrient minerals and the increasing use of systemic pesticides have served to reemphasize the importance of absorption and translocation in plant physiology. Studies of the movement of these materials have an immediate application value; at the same time they can aid in the solution of basic problems in plant behavior.A number of workers (5,12,14,24,30) have stressed the importance of surfactants in increasing the effects of herbicides applied to leaves. Bryan et al (5) and Hauser (12) showed that the rate of absorption of 2,4-D as well as the total qualtity absorbed was increased by lowering the surface tension of sprays. Some of this effect is due to the better wetting leaves (12,21) (25) showed that p32 could be absorbed through leaf surfaces. The latter workers found, however, that this absorption was reduced by the single surfactant tried in their work.The older work on translocation is reviewed by Curtis (8). Mlore recent work, particularly as it applies to the mass-flow hypothesis, is reviewed by Crafts (6). Translocation of organic molecules, up or down, is normally limited to the phloem, while inorganic substances may move either in the xylem or phloem (17

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