Abstract:

Roots is a vital part of the maize plant，however few of the research for practically regulating root function has been reported. In this study, the effects of a new mixture formulation of plant growth regulators registered in China, 30% diethyl-amino-ethyle-hexanoate • ethephon aqueous solution (30% DE AS), on maize (Zea may L. cultivar Nongda3138) were measured and evaluated in the cultivated condition of field and PVP-tubes. The physiological activities of roots were improved by foliage spray of 30%DE AS at the 6-leaves-expended stage of maize. The dry weight of roots, especially for the 8th layer of roots, was increased significantly by 30% DE AS. The roots activities of the 1st-4th and the 7th-8th layers were promoted at silking and filling stage, and the activities of invertase in the 1st－4th layer roots were higher than that in control. 15N tracing experiment showed that nitrogen accumulation in the whole plant and the 15N distribution in ears and roots was enhanced by 30% DEAS. The volume of root bleeding sap collected from the 1st internode of basal stem the content of total amino acids in bleeding sap were both increased. The contents of plant hormones (auxins, cytokinins, gibberellins and abscisic acid) in maize roots and root bleeding sap were also changed respectively by the foliage treatment of 30% DE AS. Cytokinins contents in root bleeding sap were increased remarkably, indicating the promoted transport of cytokinins from roots to shoots through xylem by 30% DE AS. The grain yield was increased by 11.7% and the yield components were also improved. 30% DE AS was proved to be a practical formulation of plant growth regulator for the improvements in grain productivity and physiological activities of roots mainly through the hormonal system.

Key words: Maize, Roots, Plant growth regulator, Plant hormone