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-methyl)phenoxy propionic acid], an analogue of this auxin, was also tested and the rates of callus growth were compared 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 enhancing effect 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.