Chemical movements in the above-ground part of Japanese morning-glory (Ipomoea nil) during flowering

Abstract

The concentrations of glucose, sucrose as well as Mg, Al, Ca, and Mn in tissues of Japanese morning-glory were analysed during flowering process. Plants grown in MGRL nutrient solution were harvested periodically and were cut into nine tissues. To determine element and sugar contents, neutron activation analysis and HPCE (High Performance Capillary Electrophoresis) were performed, respectively. Each element showed its specific distribution within a plant and the profile changed within a day. Magnesium and Ca concentrations were high in upper parts of the plant such as leaf, petiole, and apical bud. Manganese concentration, on the other hand, was high in the middle of the root, apical bud and leaf, but not in stem or petiole. Generally, concentrations of the elements temporally decreased at 9 h (2 h after the light was turned on) in apical bud and increased again till 19 h. Sugar concentrations also showed dynamic changes within a day. At 7 h, when the light was on, both glucose and sucrose concentrations showed the lowest level. Then both sugars increased again until 19 h to be more than 20-fold. However, there were differences between glucose and sucrose distributions in a plant. The distribution profile of glucose showed its peak below the apical bud and the lowest part of the stem. On the other hand, sucrose concentration was high both in the apical bud and in the upper part of the root.