The Application of Metabolic Pathways on Biotechnology
Herbicides
What are Herbicides?
Living in the twenty-first century, it is only natural the majority of farmers and gardners have moved past the "pick and pull" method of removing weeds, and to something more potent.
Herbicides can be defined as a multitude of chemicals utilized to manipulate or destroy vegetation deemed to undesirable. [1] [2]
Before we dig deeper into the process by which herbicides work, it is important to understand the basic structures of plants.
Click on the image to the right in order to learn more about the internal mechanics of plants!
Interesting Fact
Did you know that farmers who apply little or no chemicals to crops are usually as productive as those who use pesticides and synthetic fertilizers?
How Do Herbicides Work?
There are two major methods to classify how herbicides work:
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Mode of Action
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Site of Action
Mode of Action
The mode of action is defined as the way a specific herbicide affects a plant. It also tends to describe the way biological processes within a plant are interrupted - which simultaneously damage plant growth and development. [3] [4]
1. Amino Acid Synthesis Inhibitors
Herbicides under the classification of amino acid synthesis inhibitors prevent the creation of the essential amino acids. Within these plants, there are 20 amino acids – each with its own pathway. When an herbicide inhibits one of these metabolic pathways the formation of more than one vital plant protein is prevented.
Sulfonylureas, imidazolinones, and amino acid derivatives are the amino acid inhibitors. Herbicides included beneath the family sulfonylurea and imidazolinone inhibit the enzyme acetolactate synthase (ALS) or acetohydroxy acid synthase (AHAS).
They can be absorbed into the plant either through foliar application or through the roots – moving through the xylem and phloem to reach the area of injury. The other amino acid inhibitor, the amino acid derivatives, ceases the creation of three aromatic amino acids by inhibiting a key plant enzyme by the name of SEPSP synthase. Amino acid derivatives are absorbed through foliar application and move through the phloem.
2. Lipid Synthesis Inhibitor
Herbicides that are under this classification inhibit the production of fatty acids also commonly referred to as lipids. The synthesis of lipids within a plant is essential in maintaining normal plant growth and keeping the structure of cell membrane. So how exactly is the inhibition of lipid synthesis occurring?
To begin with, the herbicide is absorbed through the use of foliar application and is translocated through the phloem towards the areas of injury. Within the anatomy of the plant, the activity of an enzyme by the name of acetyl-CoA carboxylase is blocked prohibiting the production of fatty acids. This process takes place in the stroma of a plastid.
3. Seedling Growth Inhibitor
