Flowers

Biology No Comments

Concept:

Undoubtedly the most beautiful part of a plant is the flower. Flowers can be of many forms, sizes and colors. But they all serve the same funcion.las flowers so the plant can reproduce and form new plants.

Almost all the flowers are composed of four parts: the sepals, petals, pistils and stamens.

Flower parts

* 1. Sepals .- are a kind of green leaves that cover and protect the flower when it is still closed floral bud forming.

* 2. The petals .- are the colored parts of the flower that makes the insects are attracted to the bright colors of the flowers and the rest on them, his body is impregnated with pollen, transported to other flowers and help to the occurrence of fertilization.

* 3. Pistil gynoecium .- also called, is the female flower part responsible for producing eggs the pistil is bottle-shaped and has three parts: stigma, style and ovary.

* Stigma: glandular body, placed on top of the pistil is designed to receive pollen.

* Style: Part of the pistil that supports the stigma.

* Ovary: Bottom of the pistil which contains the rudiments of the seed.

* 4. The estambres., is the male reproductive tract of flowers, a stamen is a very thin body, like a thread, at whose end there is a bump: The anther, in the anthers produce pollen. These pollen grains are the male sex cells.

There are male flowers with stamens and pistils.

Others are female, with pistil and no stamens.

And there are flowers that have both reproductive systems: The male and female.

* The flower stalk is a little blade that connects the flower to the stem of the plant.

* The floral receptacle is part of the flower is one that holds the petals, sepals, pistil and stamens.

As they reproduce

First, the pollen grains must reach the pistil of another flower. The transport of pollen from the stamen to the pistil is called pollination in some plants the wind is responsible for arranging this transportation are other bugs, insects, birds or bats that carry out pollination.

* Ornithophily, when carried by birds.

* Entomophilous, when carried by insects.

* Anemophilous, when carried by the wind.

* Hydrophilic, when transported by water.

* Artificial, when performed by humans.

Kinds of flowers

The flowers are classified by sex:

* Hermaphrodite, when you have stamens or pistils.

* Men, when they only have stamens.

* Women, when they only have pistils.

* Dioic, when a plant flowers are unisexual male and another female unisexual flowers plant.

* Monoecious; when on the same floor are male and female flowers but at different heights.

The flowers are also classified by the shape of the corolla or petal and are named:

Film, peas, lip, cross, star, plate, cup, urn, tube, tray, horn, bell, etc.

Inflorescences

This name is given to how the flowers are grouped on the stem is divided into two groups: cluster and masters.

* A. Flowering cluster are those which have the most robust backbone secondary axes can be of various kinds.* 1) racimo.-stalk when the flowers are and are placed along the main axis: wallflower.

* 2) cluster compuesto.-secondary axes when new clusters are formed: the vine.

* 3) espiga., when the flowers have no stem and then are sitting along the main axis: verbena

* 4) espadice.-shaft is a fleshy spike, flower cartridge.

* 5) pin compuesta., when along the main axis instead of flowers are small spikes: wheat, barley

* 6) umbela., when at the end of the main shaft flower stalks are born equal, in the same plane: cherry

* 7) compuesta. umbel-when at the end of the main axis arise secondary axes, instead of ending up in flower, in small umbels kill re: Carrot

* 8) heads .- when the end of the main shaft is thick and it sat there many flowers: chamomile.

B. – Flowering cimosas: Those in which the main axis ends in bloom, and below it, another one axis which also ends in flower and can be, and biparas Unipar.

Usefulness of flores.-can-use sgte way:

* Flores .- used in ornamental for its showy flower.

* Industrial Flores .- of them are extracted essences that are used in perfumery and cosmetics.

* Nutritional .- Flores have to provide a high nutritional value.

Role of the flower.

The flowers contain the structures necessary for sexual reproduction.

* A. yarn: it is the male part formed by the filament and anther.

The female, the carpel, including stigma, which collects the pollen, the ovary containing the egg, and the like, a tube that connects the stigma to the ovary.

* B. pollen is produced in the anther.

* C. when ripe is released.

* D. each pollen grain contains two male gametes, when self-pollination occurs when pollen reaches the stigma of the same flower, but in cross-pollinated plants (the majority), pollen is transported by her air, water, insects or small animals to a different flower.

If the pollen reaches the stigma of a flower of the same species, it forms a pollen tube grows down the style and loa carrying male gametes to the egg

* E. in egg yolk sac, a male gamete fertilizes the egg cell to form a zygote that gives rise to the embryo.

The second male gamete joins two yolk sac cells called polar nuclei to form the endosperm surrounding the embryo of the seed.