Q.Trace the pathway followed by a pollen tube from the stigma to the ovule.

Once a compatible pollen grain germinates on the stigma, it puts out a pollen tube through one of its germ pores. This tube grows down through the transmitting tissue of the style, guided by chemical cues from the pistil, carrying the vegetative (tube) nucleus at its growing tip ahead of the two non-motile male gametes that follow behind it.

On reaching the base of the style, the pollen tube enters the ovary and, from there, grows toward a particular ovule, most commonly entering it through the micropyle (a route called porogamy). The tube then penetrates into one of the two synergid cells of the embryo sac, guided by the synergid's filiform apparatus, where its tip ruptures and releases the two male gametes into the …

Trace the tube step by step through each tissue layer -- stigma, style, ovary, ovule, …

Thinking the pollen tube delivers gametes straight to the egg cell -- it actually ruptures inside a synergid first; the gametes …