Pre-Fertilisation: Structures and Events

Pre-fertilisation: Structures and Events

Long before a flower is even visible on a plant, the decision to flower has already been made — hormonal and structural changes trigger the differentiation of the floral primordium, which develops into an inflorescence bearing the floral buds, and eventually the flowers themselves. Inside the flower, the two reproductive whorls — the androecium and the gynoecium — differentiate and develop, setting up everything needed for the events covered in this section.

Before a flower can produce a seed, two things must happen: the male and female gametes must form, and the male gamete must be delivered to the female gamete. This section covers that journey in three stages, each in its own section below:

• 1.2.1 Stamen, Microsporangium and Pollen Grain — how the anther produces pollen grains (the male gametophyte) through microsporogenesis.
• 1.2.2 The Pistil, Megasporangium (Ovule) and Embryo Sac — how the ovule produces the embryo sac (the female gametophyte) through megasporogenesis. …