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Fluorescence and Electron Microscopy of Cynodon dactylon Affected with a White Leaf Disease in the Sudan
Author(s) -
Dafalla G. A.,
Cousin M. T.
Publication year - 1988
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1988.tb00987.x
Subject(s) - phloem , biology , cynodon dactylon , sieve tube element , botany , chlorosis , xylem , electron microscope , fluorescence microscope , vascular bundle , fluorescence , physics , quantum mechanics , optics
A disease characterized by complete chlorosis of plant foliage was recently observed in Cynodon dactylon L. naturally growing in central Sudan. Severely affected plants were stunted with short internodes and small inward folded leaves. Examination of sections from paraffin embedded leaf and rhizome fractions, stained with a DNA‐binding fluorochrome Bisbenzimid H 33258, and observed in a fluorescent microscope revealed abnormal amounts of DNA material in the phloem sieve tubes of diseased plants. More intense fluorescence was also observed in the xylem region and was shown to be due to the presence of a rod‐shaped bacterium. No such anomalies were observed in healthy plants. Electron microscopy of ultrathin sections prepared from phloem zones, reacting with fluorescence in light microscopy revealed the presence of pleomorphic prokaryotes in the sieve tube elements of such zones. No helical forms were observed in semi‐thin sections from the same plant material, suggesting the MLO nature of these prokaryotes.