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The leaf: photosynthesis site


Of extremely variable format, a complete sheet is formed by a “cabinho”, the petiole, and a flat surface with two faces, the limbo traveled by ribs.

The main function of the leaf is to serve as the site where photosynthesis is performed. In some plants there are modified leaves that perform specialized functions, such as insect trapping leaves of insectivorous plants and cactus thorns.
A sheet always originates from a side gem from the stem. There are two basic types of leaves as to the type of rib they have: paralyelinatedtypical of monocotyledons and reticulinérveas, common in eudicotyledons.

Eudicotyledons they are one of two major classes of angiosperms; initially contained within the group of dicotyledons, which was dismembered for not being monophyletic.

The prefix I means trueso this term would mean the plants that actually have two cotyledons. This group differs from the old dicotyledonous in that it presents only plants that have triapertured pollen grain, characteristic derived from a common ancestor, which makes the group monophyletic.

Some special leaf structures

In some plants, mainly monocotyledons, there is not a tissue itself, but a structure known by the name of sheath, which serves as a connecting element of the leaf to the plant. This is the case, for example, with corn leaf. In eudicotyledons, near the petioles, there are structures of different shapes - they can be pointed, laminar or thorn-shaped - known as stipulations.

The shape and color of the leaves are very variable and some of them draw attention for their peculiar structure. This is the case for modified leaves present in carnivorous plants, whose adaptation helps in the capture of insects. It is also especially interesting to color certain bracts, small leaves modified at the base of the flowers, present: so colorful, they act as an important element for insect attraction.


Dionaea Muscipula- Carnivorous plant