Mecoprop as a growth factor in wheat and rye tissue cultures

Wheat and rye calli were induced on Murashige-Skoog medium by the addition of 2.4-D[(2,4-dichlorophenoxy)acetic acid]. The effect of Mecoprop [2(4-chloro-2-methy1)phenoxy propionic acid], an analogue of thisauxin, wasalso tested and the rates ofcallusgrowth werecompared with the ones obtained with 2.4-D. On Murashige-Skoog medium, Mecoprop induced and supported callus growth of the various cereals tested more efficiently than did 2.4-D. This effect was more pronounced on wheat callus. When both auxins were present in the culture medium, the enhanc- ingeffect of Mecoprop was slightly higher. The specific affinity of both auxins for wheat chromatin was measured. The results indicated that both substances, 2.4-D and Mecoprop. selectively dissolve wheat chromatin. However, lower concentrations of Mecoprop than of 2,4-D are required to dissolve the same amount of chromatin. It is concluded that in cereal cell cultures, Mecoprop is a more efficient growth factor than 2.4-D