Fine Structural Aspects of Cotton Fiber Attachment to the Seed Coat: Morphological Factors Affecting Saw Ginning of Lint Cotton

Abstract

We analyzed cytological aspects of fiber attachment and the effect of hand and saw ginning with transmission and low-temperature electron microscopy At the junction of the lint fiber to the seed coat surface there is an angular region or elbow, containing thick primary cell-wall material that apparently adds to the strength of fiber attachment to the seed coat. A protective wax layer covers the entire seed coat surface and is continuous along the surface of all fibers. Removal of full-length lint fibers during saw ginning results in a clean separation from the wax layer and primary wall just above the elbow junction, as occurs with hand ginning. Separation can be by cutting, in which case secondary cell wall is severed at the seed coat surface, or by pulling away of the intact fiber along with secondary cell-wall material present in the shank region of the fiber cell. These findings indicate that improving the yield of full-length lint fibers during saw ginning may require pretreatments to loosen the cell-wall structure at the neck region. This may involve partial dissolution of the cuticular wax layer on the fiber to improve penetration of any aqueous pretreatment(s).