The generative cell acquires a fusiform aspect with a lobulate outline (Fig.
The generative cell is surrounded by numerous vesicles with a fibrilar content of low electron density in contact with more and smaller vesicles (Fig.
The generative cell of the mature pollen grain is enclosed by the vegetative one.
Quinn has made ceramic pieces that represent reproduction in three organisms--the hydra, a single-cell organism that reproduces itself; the combination of prothallial cells, generative cell
, tube cell, and wings from the plant world; and the oviduct (or Fallopian tube) found in human beings.
But these are localized in the cytoplasm of both the vegetative and the generative cell (Franchi et al.
In early plastid exclusion, there is either a priori exclusion of plastids from the generative cell at the time of first haploid mitosis or a posteriori exclusion afterward (Pacini et al.
Plastids are incorporated, remain in the generative cell, and participate in the formation of the zygote (Hageman & Schroder, 1989; Mogensen, 1996; Nagata et al.
In fact, those in the generative cell remain proplastids, whereas those in the vegetative cell may differentiate into amyloplasts (see above).
Actually, Poaceae belong to a species with cytoplasmic maternal inheritance (Hageman & Schroder, 1989), meaning that semi-autonomous organelles within both the vegetative and the generative cells are programmed to disappear at the end of pollen-tube germination.
Disappearance of plastid and mitochondrial nucleoids during the formation of generative cells of higher plants revealed by fluorescence microscopy, Protoplasma 141:149-159.
The selective increase or decrease of organellar DNA in generative cells just after pollen mitosis one controls cytoplasmic inheritance.
Decrease in mitochondrial DNA and concurrent increase in plastid DNA in generative cells of Pharbitis nil during pollen development.