Question

To obtain virus-free plants through tissue culture, the best method is?
A) Anther culture
B) Meristem culture
C) Protoplast culture
D) Embryo rescue

Answer 1

Hint: Tissue culture is commonly used as a collective term to describe all kinds of in vitro plant cultures although strictly it should refer only to the cultures of unorganized aggregates of cells. Cultures are generally initiated from sterile pieces of a plant. These pieces are termed explants and may consist of pieces of organs, such as leaves or roots, or maybe specific cell types, such as pollen or endosperm.

Complete step-by-step answer:
The major advantage of meristem culture is that it provides clonal propagation with maximal genetic stability and the production of virus-free plants. Apical meristems in plants are suitable parts for the production of virus-free plants since the infected plant’s meristems typically are either nearly or virus-free.
The reasons proposed for the escape of meristem from virus invasion are:
1) viruses readily move in a plant body through the vascular system which is absent in the meristem.
2) High metabolic activity in the actively dividing meristem cells does not allow virus multiplication.
3) The virus inactivating systems in the plant body, if any, has higher activity in the meristem than in any other region. Thus, the meristem is protected from infection.
4) A high endogenous auxin level in shoot apices may inhibit virus multiplication. 
Viruses move readily In the vascular system, in meristem culture because in meristems there is a high metabolic activity in the actively dividing meristematic cells that do not allow virus replication. 
 
Hence the correct answer is option B.

Note: Meristematic culture retains the power of division long after embryogenesis is over. Based on their position in the plant, meristems are classified into three types: Apical, intercalary and lateral meristems.