Anatomy and Microchemistry of the Cotton Seed

The cotton seed is composed of embryo, endosperm, perisperm, inner pigment layer, palisade (Malpighian) layer, colorless layer, outer pigment layer, and epidermis including lint hairs. 2. Traces of starch, in addition to oil and protein, occasionally occur in the cells of both young and mature embryos. 3. The substances commonly recognized as pentosans in the hulled seeds are located in the resin glands. These glands no doubt contain various other substances. 4. The cell walls of the embryo are composed chiefly of cellulose. 5. Starch, oil, and protein occur within the cells of the endosperm. The cell walls of this tissue are composed chiefly of cellulose. 6. Large quantities of starch are found in the two integuments of the developing ovule. It disappears, however, before maturity. 7. The pigmentation which occurs in the cells of the two pigment layers, and to a less extent in the palisade layer and epidermis, is associated with a hardening of the protoplast. 8. The palisade layer is a part of the inner rather than of the outer integument. 9. The cell walls of the epidermis are composed chiefly of cellulose. Those of the perisperm and colorless layer become lignified before maturity. In the two pigment layers the reaction was quite indistinct on account of the colors naturally present, but the walls appear to be composed of lignocellulose. The palisade layer of the seed coat contains cellulose and lignocellulose.