Trees typically experience mid-day water depressions due to water evaporating out of the plant's stomata (a tiny opening or pore in plant leaves that intakes carbon dioxide, which is needed for photosynthesis). To understand how the water stress influences carbon's movement from the leaves (where production begins) to the roots, trunk and shoots (where the water is needed), PhD candidate Jessica Gersony (Holbrook Lab) measured carbon and water traits of five mature red oak trees over the course of 24 hours at Harvard Forest.
Working with Holbrook lab members, Gersony and researchers discovered the midday water depression does not impede carbon movement and that carbon that does not immediately leave the leaf aids in preventing the leaf from wilting. The study published in Plant Physiology, is important for understanding the robust carbon transport and phloem functioning (the vascular tissue in plants that transports sugars and other metabolic products from the leaves) during mature trees' water depressions.