RELATION OF HYDROPHILIC COLLOIDS TO HARDINESS IN CABBAGE, BRUSSELS SPROUTS, AND ALFALFA PLANTS AS SHOWN BY THE DYE ADSORPTION TEST

Abstract

Adsorption of malachite green from solution by fresh macerated plant tissue was used to determine hydrophilic colloid content and its relation to hardiness as shown by freezing tests. Random tests on a large number of plants showed greater adsorption with longer hardening up to 5 days, but considerable variations were found in individuals. Plants shown by freezing before-hand to be hardy showed greater adsorption than non-hardy plants. Older plants showed greater hardiness as a rule than younger ones, although a greater proportion of mechanical tissue rendered accurate observation of injury by freezing more difficult. Tests with certain specific dyes showed that: (1) pectic substances may be partially responsible for cold resistance; (2) lignin and allied substances and perhaps proteins are apparently converted into other compounds in hardening; and (3) protoplasmic constituents rather than those of the cell wall are probably of primary importance in hardiness of the plant cell to cold.