Pigment Glands of Cottonseed. II. Nature and Properties of Gland Walls

Abstract

1. The cottonseed pigment gland has been shown to possess a rigid, thick wall inclosing a gelatinous suspension of the gland pigments. 2. The gland wall consists of five to eight irregularly shaped, curved plates,which appear to be composed of cellulose impregnated with pectin, hemicellulose, and other unidentified uronic acid derivatives. The glands are heavily incrusted with cutin. 3. The pigment glands have been shown to be resistant to the action of most reagents except water and polar organic liquids of low molecular weight. Their reaction to water consists in the immediate rupture of the wall along one or more of the seams between the plates, followed by expulsion of the gland contents as finely divided suspended particles. Water-miscible, polar organic liquids of low molecular weight affect the glands very much more slowly than water; and the extremely slow action of other organic liquids has been shown to be attributable to their slight moisture content. 4. The existence of a highly resistant pigment gland wall has been proposed to explain the anomaly of the relative stability of reactive polyphenolic pigments in cottonseed. The sensitivity of the glands to moisture has been proposed to explain various changes observed during maturation of cottonseed as well as changes which occur during the storage of moist cottonseed.