transpiration stream


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transpiration stream

the flow of water through a live plant as a result of water loss due to TRANSPIRATION through the leaves.
References in periodicals archive ?
This paper's estimation of sugarcane herbicide bioconcentration relies on several assumptions: degradation in the soil and its metabolism and dilution in the plant are described by first order kinetic equation; the plant uses the water transpiration stream to uptake the herbicide from the soil solution; soil solution herbicide present in concentrations that are available for plant uptake; and the plant distributes the herbicide throughout itself by transpiration.
(TRAPP et al., 2003; PARAIBA 2007; PARAIBA et al., 2010), where [M.sub.p] (kg [ha.sup.-1]) is the total plant fresh biomass, Q (L [day.sup.-1] [ha.sup.-1]) is the plant transpiration rate, [TSCF.sub.soil], is the herbicide concentration factor in the transpiration stream in relation to the soil solution, [C.sub.W] ([micro]g [L.sup.-1]) is the soil solution herbicide concentration, [k.sub.E] ([day.sup.-1]) is the herbicide transformation rate in the plant, [k.sub.G] ([day.sup.-1]) is the plant growth rate, [C.sub.P] ([micro]g [kg.sup.-1]) is the plant herbicide concentration, and [K.sub.PW] (L [kg.sup.-1]) is the herbicide plant-water sorption coefficient or herbicide bagasse-water sorption coefficient measured as described in the sorption experiments.
In plants stomata response to soil drying is mediated by ABA, originating from roots and transported to the shoot via the transpiration stream. ABA under drought is produced in dehydrated roots, transported to the xylem and regulates stomatal opening and leaf growth in the shoots.
Much of the ABA in the transpiration stream is taken up and metabolized by the mesophyll cells.
The researchers modified genes specifically around the plant's water conducting pipes (xylem) so that salt is removed from the transpiration stream before it gets to the shoot.
It belongs to the basic concept of this theory to consider the transpiration stream to be forced merely by the surface tension of the transpiring menisci in the leaves.
Calcium is usually considered phloem immobile, and its movement in plants generally follows the transpiration stream via the xylem (Hanger, 1979; Hanson, 1983; Kirkby and Pilbeam, 1984; Marschner, 1974, 1986).
The VL/Con treatment may have provided seeds with high levels of Ca by the same apoplastic pathway or via the transpiration stream. Plants subjected to the Very Low and the VL/Con treatments produced seeds with high Ca concentrations in 1992.
This is the same conclusion as that reached by Grubb (1977) who reported various experiments and observations that showed that transpiration rates were not directly related to the amounts of ions transported, and by Smith (1991) who reviewed the relationship between ion transport and the transpiration stream and concluded that as the rate of flow decreased the concentration in the xylem sap increased, thus maintaining a supply of nutrients to even slowly transpiring leaves.
Ion transport and the transpiration stream. Botanica Acta 104:416-421.
If no recycling of minerals from tissue to the xylem stream occurred, then x would represent the average mineral concentration in the transpiration stream during the period represented by m and R, and if x were constant, the relationship of m to R would be linear.