The Absorption of Water by Leaves in an Atmosphere of High Humidity

Negative transport & resistance to water flow through plants

“…They demonstrated that tomato plants can absorb water from a saturated atmosphere, transport it to the roots, and build up the soil moisture to or above the field capacity. Other investigators repeated the experiments of Breazeale but could get no evidence of actual water secretion by roots (9,10,25). Stone,Shachori,and Stanley (22) concluded that negative transport occurs only when the temperature is allowed to fluctuate and is caused by vapor pressure gradients and not by any active secretive force within the plant itself.…”

Water Absorption by Needles of Ponderosa Pine Seedlings and Its Internal Redistribution

“…However, when the seedlings were removed from the soil at this time and examined, succulent white root tips which are normal on a healthy actively growing seedling were absent. Furthermore when these same seedlings were placed with their roots in (5,6,7,8,18,19).…”

“…Haines (18,19) enlarged upon the empty flask experiment and obtained a similar accumulation of water in the flask with either a tomato plant or a cotton wick. However, if the temperature in and around the flask was held constant, water failed to accumulate.…”

Moisture Transfer between Plants through Intertwined Root Systems.

“…Although several theories have been advanced to account for loss of water through roots under various environmental conditions-loss in response to tension gradients within continuous moisture films between the roots and soil particles (3), loss by exudation (2), and loss as vapor along a vapor pressure gradient between the root and the surrounding atmosphere (5,6,14)-the way in which water molecules moved out of the DT roots in these experiments is uncertain.…”