Excised juice vesicle stalks from mature lemon fruits manifest mitotic activity and cell proliferation when incubated on attenuated nutrient solutions consisting maximally of two mineral salts and sucrose or minimally of sucrose alone. Neither cell proliferation nor mitotic activity become manifest in vesicle stalks incubated on glass-distilled water alone or on mineral salts without sucrose. The findings presented here demonstrate that mitosis and cell proliferation can be activated in this tissue system on nutrient media far simpler in composition than any of those usually employed for higher plant cell or tissue cultures. Evidence is also presented here which suggests that cell wall deformation in the form of wall growth is required for the manifestation of mitotic activity in this tissue system.