What are flowers for?
After pollination and fertilization, the flower undergoes an extraordinary change. Of all the components that were seen before, only the peduncle and the ovary are left. Everything else degenerates.
The ovary undergoes a major change, develops and now we say it has become fruit. Inside the eggs become seeds.
Thus, the great novelty of angiosperms in terms of reproduction is the presence of fruits. All components of the flower we study participate in the reproductive process that will culminate in the production of seeds within the fruit. In all angiosperm this is so, but it must be remembered that there are variations: there are different shapes of fruits and different amounts or even no seeds.
When the plant has inflorescences for reproduction, the fruits formed will also be gathered and constitute the fruitlessness. This is the case of grapes, blackberry, jackfruit and ear of corn.
How fruit formation occurs
Pollination and fertilization
Pollination It is the transport of pollen grains from anthers, where they form, to the stigma, usually from another flower. Pollination is the first step towards the approximation of female and male gametes, essential for fertilization to occur.
The transport of pollen to the stigma is done by pollinating agents, which may be wind, insects or birds.
THE wind pollination is called anemophilia (from Greek anemos, wind). There are several adaptations that favor this type of pollination. The flowers of anemophilous plants usually have feathery stigmas, which provide greater surface for receiving pollen grains. Their anthers usually have long, flexible, wind-wafting fillets, which make pollen dispersion easier. In addition, anemophilous plants often produce large amounts of pollen grains, which increases the chances of pollination.
Entomophilia and Ornithophilia
Insect pollination is called entomophilia (from Greek we love, insect) and bird pollination, ornithophilia (from Greek ornithos, birds). Animal-pollinated flowers often have characteristics that attract pollinators, such as showy corolla, odorous glands, and producers of sugary substances (nectar).
There are even flowers that produce two types of stamens, one with fertile but unattractive pollen grains and one with attractive and edible pollen. The animal in search of edible pollen impregnates with fertile pollen, transporting it from one flower to another.