Explant - Shoot apical meristem lies in the 'shoot tip' beyond the youngest leaf or first leaf primordium ; it measures upto about 100 µm in diameter and 250 µm in length. Thus a shoot-tip of 100-500 11m would contain 1-3 leaf primordia in addition to the apical meristem.

In practice, shoot-tips of up to 1 mm are used when the objective is virus elimination. Shoot-tip culture is widely used for rapid clonal propagation for which much larger, e.g., 5-10 mm, explants are used.

Therefore, most cases of meristem culture are essentially shoot-tip cultures. Nodal explants of various sizes are also commonly employed for rapid clonal propagation.When the objective is vegetative propagation, the size of shoot-tip used for culture is not important.