Chloride and Sulphate Absorption from Culture Solutions by Egyptian and Upland Cotton Seedlings

Abstract

The physico-chemical properties of the leaf tissue fluids have been found to differentiate the Egyptian and Upland types of cotton, in addition to the external botanical characters. An extended series of determinations by HARRIS and his associates (I-5), upon the tissue fluids of the two types of cotton, have yielded the most interesting conclusion that they are differentiated with respect to the osmotic concentration, specific electrical conductivity, hydrogen-ion concentration, chloride and sulphate content. The tissue fluids of the Egyptian types had a higher osmotic concentration, specific electrical conductivity, and chloride content, but a lower sulphate content than those of the Upland types. The hydrogen-ion concentration of F, hybrids was intermediate between those of the two parental forms, being higher than that of the Egyptian but lower than that of the Upland parent. The plants were grown under irrigation, and recognition was made of the influence of substratum heterogeneity, which is a universal characteristic of experimental fields (6). It seemed of interest to study the absorption of chloride and sulphate from culture solutions by Egyptian and Upland types of cotton seedlings, in order to ascertain whether or not the Egyptian type absorbs larger quantities of chloride and the Upland types larger quantities of sulphate. In culture solutions it was possible to maintain a given concentration of the chloride or sulphate ion in the nutrient medium, quite in contrast with the known fluctuations throughout a given soil mass under irrigation (7). The cultures consisted of one-liter Pyrex beakers with heavily tinned, perforated lids to support the seedlings. The seeds employed were secured from W. B. CAMP, Agronomist in charge of the United States Cotton Field Station at Shafter, California, and from the Uni-