Chemicals play an important role in inducing mutations in plants by altering the DNA structure and causing changes in genes. This process is called chemical mutagenesis and is used in plant breeding and genetic studies to create new traits.
How chemicals induce mutations
Chemical mutagens cause mutations by:
- Changing the chemical structure of DNA bases, leading to mispairing during DNA replication.
- Breaking the DNA strands or interfering with DNA repair.
- Substituting one base for another, resulting in base substitution.
These actions alter the genetic code, producing point mutations, deletions, or insertions in the DNA sequence.
Common chemical mutagens used in plants
- Ethyl Methane Sulfonate (EMS) – causes point mutations by changing single bases.
- Methyl Methane Sulfonate (MMS) – similar to EMS, modifies DNA bases.
- Sodium Azide (NaN₃) – effective in cereals like wheat and barley for producing gene mutations.
- Nitrous Acid (HNO₂) – changes the base pairing of nucleotides.
- Hydroxylamine – alters cytosine bases, causing mispairing.
Applications in plant breeding
Chemical mutagenesis helps in developing new plant varieties with improved traits such as:
- Disease resistance
- Drought tolerance
- Higher yield
- Better nutritional quality
It also helps in creating genetic variation for research and selection.
Precautions
Chemical mutagens must be used carefully, as high concentrations can cause lethal mutations or chromosomal damage.
Summary
Chemicals induce plant mutations by changing DNA bases or structure. When used in controlled amounts, they help plant breeders develop new, improved varieties and study gene functions.