Editing Flowering plant (section)

=== Fertilisation and embryogenesis ===

{{main|Fertilization|Plant embryogenesis}}

[[Double fertilization]] requires two sperm cells to fertilise cells in the ovule. A [[pollen]] grain sticks to the stigma at the top of the pistil, germinates, and grows a long [[pollen tube]]. A haploid generative cell travels down the tube behind the tube nucleus. The generative cell divides by mitosis to produce two haploid (''n'') sperm cells. The pollen tube grows from the stigma, down the style and into the ovary. When it reaches the micropyle of the ovule, it digests its way into one of the synergids, releasing its contents including the sperm cells. The synergid that the cells were released into degenerates; one sperm makes its way to fertilise the egg cell, producing a diploid (2''n'') zygote. The second sperm cell fuses with both central cell nuclei, producing a triploid (3''n'') cell. The zygote develops into an embryo; the triploid cell develops into the endosperm, the embryo's food supply. The ovary develops into a fruit and each ovule into a seed.<ref>{{cite journal |last=Berger |first=F. |date=January 2008 |title=Double-fertilization, from myths to reality |journal=Sexual Plant Reproduction |volume=21 |issue=1 |pages=3–5 |doi=10.1007/s00497-007-0066-4 |s2cid=8928640 }}</ref>