In details

Pteridophytes


Ferns, ferns, ferns and horsetails are some of the best known examples of pteridophyte plants.

The word pteridophyte comes from the Greek pteridonwhich means 'fetus'; more phyton, 'plant'. Notice how budding leaves have a shape that resembles the position of a human fetus in the womb. Prior to the invention of steel sponges and other products, pteridophytes such as the "horsetail", which looks like a horse's tail and have very rough leaves, were widely used as a cleaning tool. In Brazil, the sprouts of the fern or the fern-eagle, known as food in the form of stews.

Currently, the importance of pteridophytes for human interest is mainly restricted to their ornamental value. It is common for houses and gardens to be embellished with ferns and fences, among other examples.

Throughout Earth's evolutionary history, pteridophytes were the first vegetables to present a system of nutrient-carrying vessels.


Horsetail, pteridophyte of the genus Equisetum.

This allowed a faster transport of water through the plant body and favored the emergence of large plants. In addition, conductive vessels represent one of the acquisitions that contributed to the adaptation of these plants to terrestrial environments.


Fern


Xaxim

The body of the pteridophytes has root, stem and leaf. O stem of current pteridophytes is usually underground, with horizontal development. But in some pteridophytes, such as the xaxins, the stem is aerial. In general, each leaf of these plants is divided into many smaller parts called leaflets.

Most pteridophytes are terrestrial and, like bryophytes, preferentially live in humid and shady places.

Pteridophytes Reproduction

Like bryophytes, pteridophytes reproduce in a cycle that has one sexual and one asexual phase.

To describe breeding in pteridophytes, let us take as an example a commonly cultivated fern (Polypodium vulgare).

The fern is an asexual spore-producing plant. Therefore, it represents the phase called sporophyte.

At certain times, on the underside of the ferns' leaves dark spots called serums. The emergence of sera indicates that ferns are in breeding season - in each serum numerous spores are produced.


Sera on Fern Leaves

When the spores mature, the serums open. Then the spores fall into the damp soil; each spore can germinate into a protalo, that heart-shaped little plant shown in the scheme below.

O protalo It is a sexed plant that produces gametes; therefore, it represents the phase called gametophyte.


Ferns Reproductive Cycle

O protalo ferns contain structures where they form anterozoids and oospheres. Inside the protalo there is enough water for the anterozoid to move in liquid and "swim" towards the oosphere, fertilizing it. Then appears the zygote, which develops and forms the embryo.

The embryo, in turn, develops and forms a new fern, that is, a new sporophyte. As adults, ferns form serums, starting a new breeding cycle.

As you can see, Both bryophytes and pteridophytes depend on water for fertilization.. But in the bryophytes, the gametophyte is the lasting phase and the sporophytes the passing phase. In the pteridophytes the opposite is true: the gametophyte is transient - dies after gamete production and fertilization occurs - and the sporophyte is long lasting, as it remains alive after spore production.