A leaf of a grapevine (Vitis vinifera ) growing in a glasshouse, photographed just after dawn in early summer, obtain dissolved soil nutrien

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A leaf of a grapevine (Vitis vinifera ) growing in a glasshouse, photographed just after dawn in early summer, obtain dissolved soil nutrients by absorbing them through their roots. During daylight, the nutrients are drawn upwards within the xylem cells of the plant, as water evaporates from the leaves via open stomatal pores on their surface (transpiration). At night, roots continue to absorb mineral ions, but the stomatal pores are closed. The ions within the xylem fluid raise its osmotic pressure, ( so-called root pressure) and water is drawn into the xylem from surrounding cells in the plant by osmosis. The excess fluid escapes through surface cells known as hydathodes, causing droplets to form at the leaf edge. On still warm mornings, guttation is the cause of \dew\" on plants growing n the open; on cool mornings, dew is caused by condensation of water from the air"

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Size: 3413px × 5121px
Photo credit: © DR JEREMY BURGESS/SCIENCE PHOTO LIBRARY / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: biological, biology, botanical, botany, dew, grapevine, guttation, hydathode, leaf, osmosis, osmotic, pressure, root, transpiration, vinifera, vitis, xylem