Diffusion of tritiated water into roots as influenced by water status of tissue

Ordin, Lawrence; Gairon, S.

doi:10.1104/pp.36.3.331

Cited by 14 publications

(6 citation statements)

References 7 publications

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“…There has been some speculation (Slatyer, 1967) that the initial effects of WS (such as decreased turgor) might reduce compression between adjacent cell walls; this would consequently increase the permeability of apoplastic water movement. This hypothesis was supported by the earlier observation that WS-roots displayed enhanced water isotopic exchanges (Ordin and Gairon, 1961). Furthermore, there is evidence that actual cell membrane permeability to water may be increased at low turgor levels (Zimmerman and Steudle, 1974;Steudle and Zimmerman, 1974).…”

Section: Ws-indueed Permeabilitymentioning

confidence: 73%

The effects of water-stress on leaf H2 18O enrichment

Farris

Strain

1978

Radiat Environ Biophys

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Water-stress experiments with Phaseolus vulgaris L. were undertaken to determine the transpiration rate dependency of the naturally occuring leaf H2(18O) fractionation process. Water-stress leaf H2(18O) levels were observed to be unexpectedly higher than controls. Speculations on the cause of this phenomenon are discussed. Since transpiration rate variations should theoretically affect only the rate and not the extent of leaf H2(18O) fractionation, the respective time courses for water-stressed and control leaf H2(18O) accumulations were compared. Water-stressed leaves displayed a slower rate of isotopic enrichment relative to controls, as was predicted from their reduced transpiration rate. In an absolute sense, however, both control and water-stress leaf H2(18O) fractionation rates were markedly greater than projected values from the existing model. Consequently, transpiration rates cannot be derived accurately at present from the observed rates of leaf H2(18O) discrimination. Several modifications of the theory are also considered.

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Section: Ws-indueed Permeabilitymentioning

confidence: 73%

The effects of water-stress on leaf H2 18O enrichment

Farris

Strain

1978

Radiat Environ Biophys

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“…It is possible that the diffusion coefficient of THO may be altered near the root apex in this plant material. From studies on root sections, Ordin and Gairon (7) showed that the diffusion coefficient for THO in Vicia and Zea roots varied between 5 andl 20 % of the value reported by Wang et al (10) for the free-diffusion coefficient of THO in HHO.…”

Section: Discussionmentioning

confidence: 99%

“…Ordin and Gairon (7) have studied the effect of osmotic substrate on the diffusion rate of tritiated water into root sections of Vicia and Zea. They found that while osmotic stress administered with mannitol had no effect on the equilibration of tritiated water in Zea an enhancement was observed in Vicia roots.…”

Section: Movement Of Tritiatedmentioning

confidence: 99%

Movement of Tritiated Water in the Root System of Helianthus annuus in the Presence and Absence of Transpiration

Raney

Vaadia

1965

Plant Physiol.

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“…Thus, a fivefold increase in Rim, with the remaining variables constant, would only double the value of D. Even if 2=0.99 Fin, the value of D would be increased by a factor of less than 2. In our experiments with barley, although some of the la- Viciafaba root segments (Ordin & Gairon, 1961) 1.8…”

Section: Application Of the Model System To Plant Rootsmentioning

confidence: 98%

“…These investigations have included studies on plant roots to elucidate the pathways of radial movement of water and the location of the tissues presenting major resistance (Ordin & Gairon, 1961;Woolley, 1965;Raney & Vaadia, 1965;Ginsburg & Ginzburg, 1970a). Radial diffusion across the roots of intact plants to or from the conducting tissues is difficult to study since the xylem is not directly accessible to measurements; this consideration has prompted the use of detached roots or preparations derived from them (e.g.…”

mentioning

confidence: 99%