Early stages of nematode-induced giant-cell formation in roots of Impatiens balsamina.

Giant cells induced in roots of Impatiens balsamina by Meloidogyne javanica and Meloidogyne incognita have been examined by light and electron microscopy. The first sign of giant-cell formation was division of cells surrounding a larva. Cell plate alignment appeared to proceed normally, but cytokinesis was unsuccessful and binucleate cells formed subsequently. No wall breakdown was evident then or later. The number of nuclei appeared to increase by repeated mitosis without separation by cytokinesis. Although no holes in walls were observed, wall stubs were found, and mechanisms for their formation are suggested.