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close this bookBetter Farming Series 02 - The Plant: the Stem; the Buds; the Leaves (FAO - INADES, 1976, 30 p.)
View the document(introduction...)
View the documentPreface
View the documentPlan of work
close this folderThe stem
View the documentWhere is the stem?
View the documentHow a stem is made
View the documentWhat the stem does
View the documentThe buds
close this folderThe leaves
View the document(introduction...)
close this folderHow a leaf is made
View the document(introduction...)
View the documentThe leaf-stalk
View the documentThe veins
View the documentThe shape of leaves
close this folderWhat are leaves for?
View the document(introduction...)
View the documentHow the leaf changes raw sap into elaborated sap
View the documentOrganic matter in the plant
View the documentThe plant breathes.
View the documentThe plant transpires.
close this folderSome practical applications
View the documentThe plant needs air and light
View the documentThe plant needs water
View the documentThe plant needs its leaves

How the leaf changes raw sap into elaborated sap

· The leaf feeds the plant.
It receives the raw sap; it changes the raw sap into elaborated sap.
This change is called plant material synthesis.

What is plant material synthesis?

· Heaps of sand, wood and bricks are not a house.
To build a house you have to put them together.
You join them with cement.
The cement changes the wood, sand and bricks into a house.

· Water and mineral salts cannot feed the plant.
They have to be put together, they have to be joined.
How are water and mineral salts joined together?

· The leaves live in the air.
The air contains carbon dioxide gas.
The carbon dioxide gas is made of oxygen and carbon.
The leaf keeps the carbon and gives off oxygen.

· The carbon joins the mineral sale and the water.
The mineral salts and water are changed into elaborated sap.
The elaborated sap can then feed the plant.
The carbon changes the raw sap into elaborated sap.
This is plant material synthesis.
To join sand, wood and bricks with cement requires work.
You can't have a house without men's work, men's energy.
To join water and mineral salts with carbon also requires work and energy.

· Light gives the leaf this energy.

Light enables the leaf to change raw sap into elaborated sap.
At night there is no light, and the raw sap is not changed.


Light enables the leaf to change raw sap into elaborated sap