Root Pressure


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Root Pressure

 

pressure arising in the conducting vessels of plant roots. Along with transpiration, root pressure causes sap (water and dissolved nutrients) to rise up through the stem. Root pressure is caused by osmosis: the cells of the root secrete mineral and organic matter into the vessels, creating greater osmotic pressure than in the soil solution. Root pressure is usually equal to 1–3 atmospheres (in some cases reaching 10 atm; 1 atm = 105 newtons per sq m). Root pressure depends on the conditions of vital activities of the root. At low temperatures or when oxygen is lacking, the root pressure declines, and at the death of the root it is zero. The maximum root pressure occurs during the day, the minimum at night.

References in periodicals archive ?
Moreover, root pressure develops not only in the herbaceous
water movement through the plant begins, root pressure can no longer be
Such magnitudes of root pressure would certainly be no problem
and reveal the complicated nature of root pressure, which is summarized
metabolic component (non-osmotic) of root pressure must exist.
The first principal component axis cultivar score was positively correlated with maturity, %FW in WS and in Fc, and negatively correlated with root pressure in Dv and soil moisture remaining in the soil after 3 wk of water exclusion in Dv (Table 4).
These were characterized by small flowering delay, high root pressure in Di and Dv, and high chlorophyll in Dg (Table 7).
Root pressure may also play an important role in refilling cavitated xylem vessels.
Cultivars that tended to interact positively with stress environments had root traits associated with stress avoidance (long roots, high root pressure with stress) and leaf traits that were not stress-avoiding (little rolling and high CT).
They, like grasses, may have conductive systems that operate to an appreciable extent on root pressure, and thereby are able to occupy habitats different from those of the monocots without vessels in stems and leaves.
Palms are capable of unusually high root pressures, which may be achieved by with the aid of parenchyma sheaths that can mediate ion and photosynthate content of vessels.
A survey of root pressures in vines of a tropical lowland forest.