Effects of Bay m Wheat Seeds 1099 , an ct - Glueosidase Inhibitor , on Starch Metabolism in Germinating

To examine the significance of tt-glucosidase in starch metabo]ism in vivo, wheat seedlings and seeds were treated with Bay m 1099 (Miglitol, !VLhydroxyethyl-1-deoxynojirimycin), an ct-g]ucosidase inhibitor. Bay m 1099 did not affect germination, but it inhibited growth of seed]ings at the high dosage (100pglml medium).Treatmentofnorma]lygrownseedlingswithBaym1099(1Oand1OO"glml)decreasedor-glucosidase activity with a dose response and caused accumulation of maltose in tissues with decreases in glucose. The decrease in glucose formation wou]d inhibit plant growth, which was observed particularly at higher dosages of the inhibitor. When wheat seeds were treated with Bay m 1099 at 10"g/m] for 4 days, under which the growth of the plants after germination was minimized, the ind"ction of ct-glucosidase, but not amylase, in kernels was considerab]y suppressed during germination and maltose metabolism to glucose was disturbed. In addition, the Bay m 1099 treatment decreased the initia] rate of starch degradation by 48%, compared with the control. These results suggest that wheat or-glucosidase participates in maltose hydrolysis as wel] as in the onset of starch degradatien with collaboration of amy]ase.