DIURNAL CHANGES IN STARCH AND SUGAR CONCENTRATIONS IN KIWIFRUIT LEAVES

Diurnal changes in photon yield in kiwifruit (Actinidia deliciosa cv. Hayward) indicate a sharp decline in yield by 10 am with partial recovery by early evening. Concentrations of starch and sucrose in leaves of A. deliciosa cv. Hayward change throughout the diurnal period. Concentrations of glucose and fructose remain relatively stable. Sucrose accumulates from early morning and peaks in mid afternoon. Starch accumulation follows that of sucrose with a time lag of approximately one to two hours. Sucrose and starch concentrations decline during the night. The concentrations of sucrose and starch were correlated with leaf temperature. myo-Inositol is a major carbohydrate in leaves of A. deliciosa cv. Hayward. Its diurnal pattern of accumulation is opposite to that of starch and sucrose. myo-Inositol may be utilized as a temporary storage compound and/or for maintenance of leaf turgor during the night.