ABNORMAL MICROSPOROGENESIS IN TRADESCANTIA ANTHERS CULTURED WITH SUCROSE-DEFICIENCY AND KINETIN-SUPPLEMENTATION

Abstract

A method of studying the metabolism of cell-wall formation and cell division consists of culturing anthers of T. paludosa, Sax'' Clone 5, in the basic medium of Taylor (Am. J. Bot. 37 137), substituting 4% lactose for sucrose. Microsporocytes, in anthers cultured when these cells are at meiotic diplotene, pass through both meiotic divisions in 48 hours without forming dividing walls; when kinetin is present (0.25 ppm) an arrest of nuclear division ("meiotic stasis") occurs. The alleviation of these failures by nutrient-supplementation may be used to study their underlying metabolism. A complicating feature is that the dividing walls contain a layer of callose (chemical composition unknown) not found in most tissues of higher plants. Results of supplementation with compounds associated with carbohydrate metabolism suggest that lack of metabolic energy rather than wall-precursors underlies wall-failure. Culture for short periods in prophase shows that kinetin accelerates this stage and thus possibly induces stasis by curtailing synthetic processes. Of the substances tested the effect is most markedly alleviated by citric acid and sucrose, in the presence of which kinetin induces a further immediate microspore division.