Statistical and Biological Analysis of Epiphytic Bacteria and Endotoxin on Cotton

R.J. Berni, A.J. DeLucca, and G. P. Shaffer


 
ABSTRACT

Weekly samples of cotton leaf, bract, fiber and soil were taken during the 25-week growing seasons during 1984 and 1985, at the Southern Regional Research Center, New Orleans, LA. Total and gram-negative bacteria populations were determined. Identification of gram-negative bacteria and measurement of endotoxin concentrations were performed. Both types of populations remained relatively stable until senescence, and later, frost, resulted in higher counts for each. Enterobacter agglomerans means was the predominant type present on the leaf and bract and a close second most common on fiber. Senescence affected bacterial populations on the cotton plants with some bacterial types increasing while others decreasing after senescence. Statistical analysis partitioned by sample type showed strong correlations between certain microbial and environmental variables with endotoxin levels. Gram negative bacterial count was the most accurate predictor of endotoxin levels. However, the multiple regression of endotoxin on environmental parameters suggest that week of growing season, ambient air temperature, or dew point may also be adequate predictors of endotoxin in hot, humid environments.



Reprinted from Cotton Dust: Proceedings-12th Cotton Dust Research Conference 1988 pp. 20 - 22
©National Cotton Council, Memphis TN

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Document last modified Sunday, Dec 6 1998