VIEW ARTICLE

Sulfide Inhibition of Oxidases in Rice Roots. A. I. Allam, Former Graduate Student, Department of Plant Pathology, Louisiana State University and A&M College, Baton Rouge 70803 (USA); J. P. Hollis, Professor of Plant Pathology, Department of Plant Pathology, Louisiana State University and A&M College, Baton Rouge 70803 (USA). Phytopathology 62:634-639. Accepted for publication 17 January 1972. DOI: 10.1094/Phyto-62-634.

Levels of H₂ S prevalent in Louisiana (USA) rice fields during the heading-flowering stage were toxic to rice seedlings in vitro. Rice seedling biological assays showed significant inhibition of the respiration of rice roots pretreated with H₂ S at levels as low as 0.07-0.1 µg/ml. Drastic inhibition of the activities of the metallo enzymes (cytochrome oxidase, catalase, peroxidase, ascorbic acid oxidase, and polyphenol oxidase) in roots of H₂ S-pretreated rice seedlings was also shown. These empirical data suggest that reduction of rice root oxidative capacity, terminal oxidation, and other physiological functions such as nutrient uptake by hydrogen sulfide levels occurring in Louisiana rice fields may cause hitherto unrecognized toxicant diseases of rice, manifested as reduced grain yields.