VIEW ARTICLE

Structural Integrity of the Cotton Fruit and Infection by Microorganisms. L. J. Ashworth, Jr.,, Departments of Plant Pathology, University of California, Berkeley 94720; R. B. Hine, Departments of Plant Pathology, University of Arizona, Tucson 85721. Phytopathology 61:1245-1248. Accepted for publication 24 May 1971. DOI: 10.1094/Phyto-61-1245.

Crystal violet stain was absorbed in the interplacental cavity, but not in locules of immature bolls having intact subcarpellary bracts. However, stain was readily absorbed into the pithlike subcarpellary tissue and into 5-10% of the locules of bolls whose carpellary bracts were broken off. Stain appeared to be absorbed through the broken edges of bracts. Benomyl, a systemic fungicide, was detected in carpel tissue of immature bolls in 2 days, and in lint after 10 days, but not in seed coat nor embryo tissue, indicating that benomyl is absorbed and diffused slowly within boll tissue. Our results support observations on the ontogeny and anatomy of the cotton fruit which indicate that immature bolls are closed systems that are waterproof and sterile unless the integrity of either the carpel wall or placentae is destroyed, barring direct penetration by local or systemic invaders.