Question

In a grafted plant, stock has $48$ chromosomes while scion has $24$ chromosomes. The chromosome number for root cells and eggs are

• A.
  $48\text{and}12$
• B.
  $24\text{and}24$
• C.
  $24\text{and}12$
• D.
  $48\text{and}24$

Answer 1

The correct option is A

$48\text{and}12$
Introduction of grafting
Grafting is an artificial method of vegetative propagation in which a part of the young stem or a bud (scion) of one plant is joined to a part of the stem of another genetically different plant, which bears the roots (stock).

Chromosome number for root cells
Stock has $48$ chromosomes and bears the root cells. The chromosome number in roots is diploid and will be the same as the stock, that is, $48$.

Chromosomes number for eggs
Scion has $24$ chromosomes and bears the reproductive parts. The megaspore mother cell in the ovule undergoes meiosis to form the haploid female gametophyte bearing the haploid egg cell. Thus, the chromosome number in the egg cells will be half of that of the $24$, i.e., $12$.