Fusarium oxysporumf. sp.orthoceras, a Potential Mycoherbicide, Parasitizes Seeds ofOrobanche cumana(Sunflower Broomrape): a Cytological Study

Abstract

Fusarium oxysporumf. sp.orthoceras, a potential agent for biological control of the root-parasitic weedOrobanche cumanain sunflower, attacks underground developmental stages, such as shoots, tubercles and seed germ tubes. The germination of inoculated seed was significantly reduced, and cytological investigation showed thatF. oxysporumhad penetrated and colonized dormant seeds ofO. cumana. Germ tubes of microconidia penetrated all parts of the thick, complex seed testa, and seed contents were completely destroyed. Hyphae dissolved the endosperm cell walls and metabolized the cytoplasm which was rich in lipid- and protein-bodies. Thus, the inoculation of soils withF. oxysporummay be used to reduce theOrobancheseed bank.