Q.47 Given below are two statements. One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A: Plants raised in-vitro, through tissue culture technique often exhibit morphological and genetic
variations.

Reason R: Plant genetic fidelity often gets impacted by somaclonal variations.

In the light of above, choose the correct answer from the options given below:

1. Both A and R are true and R is the correct explanation of A

2. Both A and R true but R is not the correct explanation of A

3. A is true but R is false

4. A is false but R is true

Plants raised through in-vitro tissue culture often show variations due to somaclonal effects, and the correct answer to this assertion-reason question is option 1. This SEO-friendly guide breaks down the concepts for biology students preparing for exams like CSIR NET or GATE Biotechnology.

Correct Answer

Option 1: Both A and R are true and R is the correct explanation of A

Assertion (A) Explained

Assertion A states that plants from tissue culture exhibit morphological (like altered leaf shape or height) and genetic variations. This is true because in-vitro conditions induce somaclonal variation—heritable changes from cell culture stress, mutations, or epigenetic shifts during regeneration. Factors like prolonged subculturing, hormonal imbalances, and oxidative stress trigger these in callus or suspension cultures.

Reason (R) Explained

Reason R notes that somaclonal variations impact plant genetic fidelity. This holds true as somaclonal variations cause DNA changes (e.g., point mutations, transposable element activation, chromosome rearrangements), reducing clonal uniformity and genetic stability in regenerants.

Why R Explains A

R directly explains A: somaclonal variations are the key cause of the morphological and genetic differences in tissue-cultured plants, linking the phenomenon to fidelity loss. Both statements align factually, with R providing the causal mechanism.

All Options Analyzed