Short note Starch and soluble carbohydrates in leaves of water-stressed oak saplings

Summary — Four-year-old potted saplings of Quercus petraea (Matt) Liebl were exposed to water short-age by withholding irrigation. After 10 days, predawn leaf water potential was decreased to-2.0 MPa and leaf photosynthesis was reduced by 55%. At this stage, starch and sucrose concentrations were decreased by 47 and 48%, respectively. A five-fold increase was observed in glucose and fructose con-centrations of water-stressed saplings compared with well-watered plants. These results suggested that drought-induced changes in sugar composition contribute to osmotic adjustment in this species