Pectolytic Activity of Rice Plants Infected with the Stem-rot Fungi, Helminthosporium sigmoideum Cay. and H. sigrnoideuin var. irregulare Cr. et Tullis

Abstract

Production of pectolytic enzymes in stem tissues of both healthy and stem-rot infected plants were studied. The cut-stem technique was employed for production of pectolytic enzymes. Viscometric method and reducing end group analysis were used to determine endo-polygalacturonase and exo-polygalacturcnase, while continuous titration procedure was used to measure the pectin mythylesterase activity. Endo- and exo-polygalacturonase could not be detected in tissue extracts from healthy rice stems. Extracts from infected tissues contained polygalacturonase activity. Pectin methylesterase activity was detected in healthy and diseased tissues. A considerable increase in pectin methylesterase activity of tissue extracts from infected stems was observed. 本文敍述小球菌核病病原菌，Helminthosporium sigmoideum Cav.及小黑菌核病病原菌 H. sigmoideum var. irregulare Cr. et Tullis對水稻體內果膠分解酵素產生之影響。健全水稻莖組織內沒有endo-polygalacturonase及exo-poIygalacturonae之存在，被H. sigmoideum或H. sigmoideum var. irregulare所感染之水稻莖組織內，可檢出多量之exo-polygalacturonase。健全莖組織及罹病莖組織內均合有pectinmethylesterase,唯水稻莖組織罹病後pectin methylesterase之含量增加甚多。