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The primary period of shoot extension growth on field-grown peach trees occurs in the evening. Field measurements indicate a 2-3 fold increase in growth rate occurs in the late afternoon and lasts for about 2 hours. The daily growth pattern is correlated with trends in temperature, water potential and carbohydrate concentrations. Early morning and late night growth rates are apparently limited by low temperatures. Heating shoot tips at these times causes extension rate to increase greatly above that of controls at ambient temperature. The afternoon surge in extension growth rate is correlated with recovering stem water potentials. Artificially increasing stem water potential at mid-day by reducing transpiration causes extension rates to dramatically increase 2-3 fold. Starch is accumulated in the shoot extension zone during the day and depleted during the evening surge in growth.