Cytological Studies in the Chenopodiaceae. I. Microsporogenesis and Pollen Development

Abstract

1. The primary sporogenous cells in the members of the Chenopodiaceae examined divide to form several rows of microspore mother cells. 2. Prior to the nuclear divisions of the microspore mother cells the tapetal cells divide mitotically and each cell becomes binucleate. 3. The heterotypic spindle is surrounded by cytoplasmic and granular zones in Kochia and Atriplex. Such zones are not present in Chenopodium. This stage was not observed in Salsola. 4. Remains of the heterotypic and the homoeotypic spindles persist so that the tetrad nuclei are connected by two prominent spindles and four less distinct spindles. 5. Paired thickenings appear on the cytoplasmic strands midway between each of the nuclei. The cell plate splits and a wall is laid down so that ultimately four microspores are formed. 6. The microspore nucleus migrates to the periphery of the cell and there divides to form the generative and tube nuclei. By means of cell plate formation midway between these two nuclei, two cells of equal size are ...