Microsporogenesis of <i>Saccharum spontaneum</i> with Special Reference to Its Chromosome Number

Abstract

1. The chromatin reticulum is granular in character and is more or less evenly spread out in the nuclear vacuole.2. The chromatin threads during the heterotypic prophase radiate in various directions and there is no regular parallelism.3. The synizesis is due to the gradual contraction of the reticu lum and growth of the nuclear cavity.4. The spireme formed during the synizetic contraction is doubled in some places only and single in the other portions.5. During the loosening of the spireme from the synizetic condition beautiful loops, more or less equal to the gametic number, are formed.6. Following the distribution of the spireme in the form of loops in the nuclear cavity and the separation of the individual loop by segmentation, the second contraction orsynapsis takes place.7. The pairing of the two arms of the loops, representing the two univalent chromosomes is evident.8. The nuclear membrane and the nueleolus disappear simultaneously, while the multipolar spindles suddenly appear.9. The number of the chromosomes in the haploid phase is 40.10. The bivalent ehromosomes are more or less the Same in shape and size.11. The heterotypic division takes place in a normal manner, no lagging or other irregularity was observed.12. The daughter nuclei do not pass into resting stage as usual but pass directly into a normal homoeotypic division, forming the four daughter nuclei of the pollen grains.