Articles

Flower Reproductive Organs


Androceu - Stamens and Pollen

Stamens they are elongated leaves that during evolution bend over themselves, differing in two regions: the thread, thin and elongated portion that supports the anther, which in turn protects pollen-producing pockets, known as pollen sacs.

Pollen Grain Formation

Pollen grains form in the anther pollen sacs. Pollen bags are surrounded by a fabric called tapetum, which also nourishes the cells. There are four pollen bags, each two in a teak. When the anther becomes an adult the pollen sacs break, releasing pollen grains.

Pollen Grain Structure

Pollen grains are formed by haploid cells with two nuclei: one vegetative with the function of forming the pollen tube and the other reproductive with the function of fertilizing the egg.

Pollination

It is the process of pollen release from the male part where it was formed, transport and deposition on a receiving stigmatic surface. Under favorable and compatible conditions this pollen will germinate, initiating the formation of the pollen tube (gametophytic phase) and subsequently fertilization.

It can be performed by an abiotic or biotic agent that associated with the morphological aspects of the flower determine the so-called floral syndromes. Anemophilia and hydrophilia are abiotic syndromes.

In biotic pollination, plants have developed structures or elements that are attractive to different types of animals that stimulate feeding, sexual activity or nesting where new individuals will develop. Among these elements we can cite, colors (visual appeal), odor, pollen, nectar, oil, resin, etc. Insects developed great interaction with plants, entomifilia being the main biotic syndrome. Vertebrate animals also participate in this process, ornithophilia (birds) and chiropterophilia (bats) are examples.

Ginece - Carpel and Ovary

O carpel or pistil It is a modified leaf which during evolution has folded over itself, differing in three regions:

  • ovary, dilated region that protects the eggs;
  • stigmathe upper portion is the recipient of pollen grains;
  • stiletto, the intermediate piece that connects the stigma to the ovary.

The modified carpel now has the appearance of an instrument widely used in chemistry, known as pistili, which is why it is also named. A flower can have a single carpel or several that, merging fully or partially, form stores.

Types of Carpels

The gynoecium can be simple when it is formed by a single carpel, apocarpous, when gynoecium is made up of several separate carpels and syncarp, when the gynoecium is formed by several joined carpels.

Symmetry of the flower

Important for the study of plant systematics, can be:

  • radial or actinomorphic: when the shape of the flower allows various symmetry planes to be traced.
  • bilateral or zygomorphic: with just a plane of symmetry.
  • asymmetrical: without any symmetry plan.

Floral diagram

You can represent a flower through its floral diagram. Observe the diagram below:

From the outside, it is represented: the sepals (chalice), the petals (corolla), the stamens (androceu) and the carpels (gynoecium). There is also the floral formula, which can be exemplified below:

K5 Ç(5) THE10 G2

Where:
K: represents the number of sepals
Ç: represents the number of petals
THE: represents the number of stamens
G: represents the number of carpels
( ): joined parts (prefix fallow deer or sin)