Cytochemical studies on the mitotic spindle and the phragmoplast of plant cells

Abstract

1. 1. In the mitotic spindle and the phragmoplast of fixed plant cells, cytochemical tests with staining methods were carried out for pentosenucleic acid, proteins and polysaccharides. 2. 2. In late prophase, pentosenucleic acid is accumulated in the polar caps. In the pollen mother cell of Lilium in prometaphase of the meiotic first division, pentosenucleic acid is present in a fibrous area around the chromosome group. 3. 3. The metaphase spindle contains abundant pentosenucleic acid and is clearly distinguishable from the cytoplasmic area. 4. 4. In anaphase the poleward regions of the spindle are proved to contain pentosenucleic acid as in metaphase; on the other hand, the interzonal region between the separated daughter chromosome groups gives the staining reaction for pentosenucleic acid in almost the same degree as the cytoplasm. The difference between the poleward regions and the interzonal region is discussed. 5. 5. The phragmoplast is rich in pentosenucleic acid, but the cell plate region is free from it. 6. 6. By staining with acidic dyes combined with hydrolysis of pentosenucleic acid, it was shown that pentosenucleic acid is associated with proteins in the polar caps, in the mitotic spindle and in the phragmoplast. 7. 7. The cell plate clearly shows the presence of polysaccharides. Polysaccharides already appear at the equatorial plane of the phragmoplast before it reaches the side wall.