The accumulation of chlorides in the leaf tissue fluids of Egyptian cotton with the march of the season.

Abstract

Among the physiological problems presented by the phenomenon of the differential absorption and tolerance in solution of chlorides and sulphates by the Egyptian and Upland types of cotton 1 is that of the change in the concentration of these anions with the march of the season. This problem is in reality twofold: (a) change in the concentration in one and the same organ with its development and senescence, and (b) the possible change in the concentrations found in the (leaf) tissues at as nearly as possible comparable stages of maturity at earlier and later periods in the development of the organism as a whole. The present discussion is limited to the latter phase.

The more mature cotton plant does not lend itself readily to controlled laboratory experimentation. For this and other reasons a statistical method of attack seems desirable. The problem presents some difficulties, since concentrations based on unit volumes of tissue fluid may obviously be influenced by (a) errors of judgment or the errors of random sampling in the collection of leaves at earlier and later periods, 2 and by (b) the turgidity of the tissues at the time of collection of samples grown in field cultures.

Table I shows the mean concentration of chlorides in terms of grams per liter of leaf tissue fluids from samples from the same plants in a first and second series of analyses 3 of the number (N) indicated based on cottoms grown in the Gila River Valley in southern Arizona. 4

Since the determinations of, the first and second series may be expected to be correlated, because of the influence of the individuality of the plants and of variation in the environmental conditions to which they are exposed, it is necessary to consider the correlation between the first and second determinations in calculating the probable errors of the difference between them.