Investigation of the interaction between abscisic acid (ABA) and excess benzyladenine (BA) on the formation of shoot in tissue culture of tea (Camellia sinensis L.)

The effect of abscisic acid (ABA) and excess benzyladenine (BA) on the formation of shoot from tea (Camellia sinensis L. assamica × sinensis) leaf was investigated in this research. Callus was formed and grew well when explants were cultured on LS basal medium supplemented with (in mg/L) thiamine-HCl, 1.25; pyridoxine-HCl, 0.625; nicotinic acid, 0.625; indole-3-acetic acid (IAA), 30; naphthaleneacetic acid (NAA), 30; kinetin, 0.1; myoinositol, 100; as well as 3% (w/v) sucrose. After two months, the calli were transferred to a modified B5 medium in order to regenerate plant. As a result, we observed root formation in the transferred calli to B5 medium after one month. Subsequently, the calli were transferred to the aforesaid B5 medium supplemented with ABA (2 mg/L) and excess BA (400 mg/L) to form shoot. The calli turned green and showed differentiation of globular and heart embryos when transferred to the modified B5 medium, without formation of shoot. These findings showed that the applied concentration of ABA may cause inhibition of conversion of globular and heart embryos to shoot. The increased level of BA, however, was not able to ameliorate the effect of ABA.