A scanning electron microscopic study of IAA-induced tumors in bean (Phaseolus vulgaris L.) embryos.

A scanning electron microscopic study of indole-3-acetic acid (IAA) induced tumour in the hypocotyl region of bean embryos shows a distinct morphological, structural and topographical change from the non-treated bean embryos. The IAA-induced tumour surface, in the hypocotyl region, shows distinct cell enlargement, some cellular proliferation in the parenchymatous tissue, total destruction of the epidermis and stomata and some variation in trichome structures. In dole-3-acetic acid inhibits the normal growth of the epicotyl, and, as age progresses, adventitious roots appear all over the surface. When IAA-depletion occurs, epicotyl growth resumes, which indicates that this tumour formation in bean embryos is an IAA-dependent tumour.