Contents
THE LEAF: FUNCTIONS
What is a leaf?
A leaf is a vegetative part of the plant. It generally has a flat form and a thin surface.
The leaf is one of the most important part of the plants because it is the one which is in charge of accomplishing the photosynthesis, the respiration and transpiration.
The leaf: parts
There are different types of leaves, which let us to distinguish the different kinds of plants, but essentially, each leaf is formed by the following parts:
| A) The blade 1.- Veins and midrib (midvein) 2.- Margin or edge B) Petiole |
The blade is the expanded part of the leaf. It is the most conspicuous part, what most of people identify and understand as a leaf when such a noun is mentioned.
Different types of blade
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Inside the blade the following parts can be distinguished:
| – The veins: are a like wrinkles or pipes running along the blade. They are really the vascular bundles coming from the stem throughout the petiole into the the surface of the blade. The central vein is called Midrib. The different patters they draw in different species is a trait used by botanists to distinguish a plant from the other. |
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– The margin is the rim or final limit of the blade. It can offer different forms:
Different types of margin
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– The petiole is the connection of the stem to the blade. It is the channel for the vascular bundles to arrive to it. It can be short or long. Those leaves having a petiole, no matter how long it may be, are called petiolated. There are some leaves without petiole. In this case they are called stalkless or sessile.
A petiolated leaf and a stalkless one
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Activities of leaves
Do the three following activities before the test:
Online game of Leaves
Test test on leaves for primary school children
Test what you have learned about the leaf, clicking what you think is the correct answer among the three different possibilities.
1) The extended part of the leaf is called:
petiole
edge
blade
2) The central vein of the blade is called:
stem
margin
midrib
3) The channels that distribute the sap or circulatory fluids along the leaf are called:
veins
tunnels
roots
4) Choose the correct statement:
all the leaves are sessile
all the leaves are petiolated
all the leaves have a blade
To know more about “The leaves” 
More information about plant cultivation.
