Transport and Energization in Vacuoles of Sugarcane

Abstract

The storage of sucrose in sugarcane had been of importance for thousands of years since Papua in New Guinea had selected Saccharum species for sweetness. Scientists of the nineteenth Century were also fascinated by the feature that sugarcane can accumulate sucrose up to 20% of fresh weight (Went, 1896). The physiology of sugar storage was especially elucidated by the Australian groups of Bieleski, Hatch and Glasziou. They followed the path of sucrose to the storage parenchyma, the hydrolysis to hexoses, the uptake of hexoses and the resynthesis and storage of sucrose (e.g. Gayler and Glasziou, 1972). A detailed kinetic study of storage processes was then made possible by the successful generation of sugarcane cell culture in suspension (Nickeil and Maretzki 1969) and the kinetic studies revealed that sugar uptake into the storage cells proceeds by strictly coupled proton symport with hexoses (Komor et al. 1981). By that time several procedures for isolation of vacuoles had been described (Leigh et al. 1979) and the successful isolation of intact vacuoles from sugarcane allowed more detailed studies on sugar storage (Thom et al. 1982a).