CEREAL BETA-AMYLASES - DIVERSITY OF THE BETA-AMYLASE ISOZYME STATUS WITH IN CEREALS

beta-Amylase (EC 3.2.1.2.) activity was determined in the kernels of 2 9 cultivars and inbred lines of seven cereals (Triticum aestivum L., T riticum durum L,., Hordeum vulgare L,., Secale cereale L., Avena sativ a L., Zea mays L., Sorghum vulgare L,) belonging to 4 tribes of the Gr amineae. The ratio activity/mg kernels was found to be much higher for the Triticeae than for all other tribes. Attempts were made to identi fy in one representative of each of these tribes - the <<endosperm>> a nd the <<ubiquitous>> beta-amylase according to criteria previously es tablished, namely comparison of antigenic specificities as well as in vivo and in vitro post-translational modifications (Daussant et al., 1 991). All tribes investigated exhibit the <<ubiquitous>> type beta-amy lase. The <<endosperm>> isoenzyme, however, appears to be restricted t o the Triticeae tribe. The results are discussed in terms of the signi ficance of beta-amylase for germination and with respect to current kn owledge as to the genetics of cereal beta-amylases.