A Method for Estimating Hydrophilic Colloid Content of Expressed Plant Tissue Fluids

Abstract

In the preceding paper by GORTNER and HOFFMAN2 it was pointed out that studies of the physico-chemical properties of plant saps which include only measurements of the osmotic pressure, electrical conductivity, and H-ion concentration, leave out of account the very important influence on physical properties exerted by sap colloids. By the introduction of the refractometer as a part of the field laboratory equipment, these workers have shown it possible to make rapid and accurate determinations of the moisture content of the plant saps. Utilizing the additional data thus made available, a simple method has been devised which appears to give a relative measure of the content of hydrophilic colloids. The freezing point depression of the freshly expressed plant juice is first obtained. Then, having determined the total solids 3 SCATCHARD, G., The hydration of sucrose in water solution as calculated from vapor-pressure measurements. Jour. Amer. Chem. Soc. 43:2406-2418. I92I.

From protoplasmic theory to cellular systems biology: a 150-year reflection

“…He and his students showed that a substantial amount of the water in certain plant systems does not freeze at temperatures where bulk water should do so (58). He and his students showed that a substantial amount of the water in certain plant systems does not freeze at temperatures where bulk water should do so (58).…”

The Extraction of Plant Tissue Fluids and Their Utility in Physiological Studies

“…The leaves were wrapped around the bulb of the Beckmann thermometer, and secured in place with rubber bands, or the bulb was inserted in a test-tube containing the ground leaf pulp. The use of a thermocouple, though more convenient in some respects for solids, had been shown in earlier work (4) to be less accurate, particularly in ascertaining the degree of undercooling. It was found that determinations with leaves and pulp could not be made with the same precision as with juice, but fortunately the differences proved to be so large as to make probable errors of minor importance.…”

“…By supplementing ordinary tissue analyses with analyses of the expressed fluids, the distribution of any constituent between the physiologically active and inert portions of the plant may be conveniently determined. 4 …”

Bound Water Content of Vegetative and Spore Forms of Bacteria

“…We suggested that the resistance, whether it concerned the enzymes or the bacterial protoplasm proper, might be due to differences in the percentage of bound water in the two types of cells. This suggestion was based on the report of Newton and Martin (1930) which shows that the resistance of certain plants to drought and freezing is, in part, due to their relatively high percentages of bound water.The present paper is a report of the relative amount of bound water found in the vegetative cells and spores of Bacillus mycoides, Bacillus megatherium and Bacillus subtilis, as determined by the cryoscopic method (Newton and Gortner, 1922). This method was chosen because of its relative simplicity and because of the similarity of our problem to that of Skovholt and Bailey (1935) when they determined the bound water in flour.…”

“…The present paper is a report of the relative amount of bound water found in the vegetative cells and spores of Bacillus mycoides, Bacillus megatherium and Bacillus subtilis, as determined by the cryoscopic method (Newton and Gortner, 1922). This method was chosen because of its relative simplicity and because of the similarity of our problem to that of Skovholt and Bailey (1935) when they determined the bound water in flour.…”