Pistil - How it is made and what it is used for


PLANTS: HOW THEY LIVE AND HOW THEY ARE MADE

PISTIL

The gynoecium or pistil is the set of female organs of a flower.It is formed following the transformation of said leaves carpels. It consists of three parts:

OVARY

: it can be considered as a container formed by the carpellar leaves that enclose the ovarian cavity inside which there is a placenta into which the OVULES (female gametophyte) containing the female cells (which must be fertilized by the male cells to generate a new plant).
The ovary according to its position in the receptacle can be:
  • I overcome (hypogynous flower): Ranuncolaceae, Papaveraceae, Urticaceae, Liliaceae, Leguminosae, Aceraceae, Geraniaceae, Violaceae, Crucifereae, Malvaceae, Boraginaceae, Lamiaceae, Euphorbiaceae etc.;
  • inferior (epiginous flower): Rosaceae-Rosa, Malus, Myrtaceae, Rhamnaceae, Apiaceae, Araliaceae, Dipsacaceae, Caprifoliaceae, Rubiaceae, Asteraceae, Iridaceae, Orchidaceae, Poaceae etc.;
  • semi inferior (flower perigino): Rhamnaceae, Chenopodiaceae, gen. Prunus etc.

Considering the number of carpellas that make up the ovary we can have:
  • apocarpic ovarywhen each carpel closes on itself but does not seal with the neighboring ones and each forms an ovary and therefore there are more pins (eg. Ranuncolaceae, Boraginaceae etc.);
  • syncarpic ovarywhen the carpels, in addition to closing in on themselves, weld their walls with those of the neighboring carpels forming a single ovary divided inside into one (monolocular ovary) or more niches (plurilocular ovary);
  • monocarpic ovary formed by a single pistil consisting of a single carpel.

The distinction between apocarpic ovary and syncarpal ovary is important because a syncarpal ovary will always give only one fruit while an apocarpic ovary will give more than one.
The edges of the carpels that have fused produce a so-called tissue placenta from which the ova.

STYLUS

: it is the hollow extension of the ovary in the shape of a stiletto.
The number of styles is variable and can be free or increased for the base and also of variable length. It may also happen that the styles are not apical but lateral or that branch off from the base of the ovary.

STIGMA

or

ESTIMATE

: it is the apical portion located at the end of the stylus that serves to receive and retain the pollen in order to allow the fertilization process. It can have various forms, be single or there are several or missing. Furthermore, in order to better retain pollen, there is sometimes a glandular structure that secretes viscous sugary liquids.
The shape and how a stigma develops is a further element of classification.

Once the pollen grains reach the stigma, a POLLIN TUBE is formed inside the pistil which is nothing more than a tube-shaped extension that transmits the pollen grains inside the ovary to fertilize the eggs.

After fertilization the eggs are transformed into

SEEDS

and the ovary gives rise to the

FRUIT

.

You may also be interested in the following articles:

  • PEDUNCLE
  • TALAMO or RECEPTACLE
  • PERIANTH
  • GOBLET
  • COROLLA
  • ANDROECIUM or STAMEN
  • GINECEO or PISTIL
Note
1. Image taken from the Biologados website

Video: Look Inside a Flower! Science Project for Kids


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