Mesurments of Sugars in Leaves on Apple Trees

Synthesis of some important sugars (sorbitol, sucrose, glucose and fructose) in leaves were followed, in summer and autumn on 12-year old 'Golden Delicious' apple trees (Malus domestica Borkh.)grown in the experimental orchard.The treatments encompassed fruiting and non-fruiting (picked) trees.Each treatment involved four trees.Trees from the picked treatment were defruited at 13 th of August.Leaves for sugar analysis were sampled five times.For sugar analysis we used high pressure liquid chromatography (HPLC).Concentrations were calculated using the external standard, comparing standard and sample surfaces.Sugars in leaves were slightly, but not significantly increased in non-fruiting trees.Only at the end of the season we have a higher content of sugars in the leaves of fruiting trees.Fruits represented a power sink, so the absence caused changes in sugar levels in leaves.There were only minor differences observed when sugars were compared for fruiting and non-fruiting trees.