The Application of Metabolic Pathways on Biotechnology
Inside of the Plant
Since before the birth of mankind, plants of all species have dominated the landscapes of our planet. And it has not been till the birth of our race that we have begun treatments to suppress these life forms. In order to gain a basic understanding of the extent to which man-made chemicals, such as herbicides, affect these lifeforms, it is vital to become familiar with the structure of plants.
When talking in reference to herbicide application, a plant is divided into two sections: the shoot system and the root system - as exhibited in the diagram to the left.
Applying herbicides through the shoot system would be referred to as Foliar Application. And going by way of the root system, this process would be referred to as soil application. Soil application is rather simple, as it simple enters through the root and moves its way up to the stem and leaves.
Foliar Application
The herbicide can now enter through the leaf in two ways: either through the cuticle or the stomata.
​The surface of the leaf is protected with a thin waxy layer called the cuticle. Upon closer examination, it is possible to see the cell membrane - which is composed of lipids and protein. Hydrophilic herbicides or "water loving" herbicides will not penetrate the membrane while the hydrophobic herbicides or "water-fearing" herbicides will become entrapped.
Another way for the herbicide to enter the leaf is through the stomata, which can be described as openings in the leaf that allow the passage of some compounds, including carbon dioxide.
