Callus formation and plant regeneration in standard and microexplants from seedlings of barley (Hordeum vulgare L.).

Callus was induced in standard (1 mm) leaf base explants and in cross sections (microexplants) through the seedling axis from seedlings of Hordeum vulgare L.. Reduced callus formation was observed with increasing distance from the leaf base, and explants from the first and second leaves gave the best response. In serial hand sections of the seedling axis frequency of callus formation decreased from 100% in the apical region to 5% in the basal region. Callus formed from all tissues outside the central vascular elements, except for the coleoptile and the scutellum. Plants were regenerated from callus induced from both types of explants.