Influence of ABA and 4PU-30 on the Growth, Proteolytic Activities and Protein Composition of Maize Seedlings

The experiments were carried out with germinating maize seeds (Zea mays L.), grown 6 d in the dark at 26°C. Before germination the seeds were soaked for 4 h in solutions containing 1 mM abscisic acid (ABA), 0.1 mM N₁-(2-chloro-4-pyridyl)-N₂ phenylurea (4PU-30) and their combination. The influence of plant growth regulators on the length, fresh (FM) and dry (DM) masses, proteolytic activities and soluble protein fractions in shoots, roots and endosperm were studied. As compared to control the seedlings treated with ABA showed lower length, FM and DM of shoots and roots, and lower proteolytic activities. As a consequence of suppression of both growth and protein breakdown, these seedlings possessed higher protein content in endosperm. 4PU-30 partially decreased the ABA suppressing effects.