We developed a system to study the influence of altered gravity on carbohydrate metabolism in excised wheat leaves by means of clinorotation. The use of excised leaves in our clinostat studies offered a number of advantages over the use of whole plants, most important of which were minimization of exogenous mechanical stress and a greater amount of carbohydrate accumulation during the time of treatment. We found that horizontal clinorotation of excised wheat leaves resulted in significant reductions in the accumulation of fructose, sucrose, starch and fructan relative to control, vertically clinorotated leaves. Photosynthesis, dark respiration and the extractable activities of ADP glucose pyrophosphorylase (EC 22.214.171.124), sucrose phosphate synthase (EC 126.96.36.199), sucrose sucrose fructosyltransferase (EC 188.8.131.52), and fructan hydrolase (EC 184.108.40.206) were unchanged due to altered gravity treatment. © 1994, Gustav Fischer Verlag, Stuttgart. All rights reserved.