Cotton embryogenesis: The identification, as nuclei, of the X-bodies in the degenerated synergid.

The "x-bodies" present in the degenerated synergid of cotton were shown to contain DNA by specific staining with Azure B, the Feulgen procedure, and by labelling with (3)H-actinomycin D. They are identified on a morphological basis as the degenerated vegetative nucleus of the pollen tube which is always found in the degenerated synergid tip, and as the degenerated synergid nucleus, which is found about halfway up the degenerated synergid near the side towards the central cell. The positions of these nuclei and of some other structures have been used to construct a tentative description of some of the events occurring during pollen-tube discharge and movement of the sperm through the synergid. Some observations which may indicate some of the factors involved in interaction of the synergid and pollen tube cytoplasm are discussed.