Induced Changes in Permeability of Plant Cell Membranes to Water

Glinka, Z.; Reinhold, Leonora

doi:10.1104/pp.49.4.602

Cited by 54 publications

(20 citation statements)

References 16 publications

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“…Table V shows the diffusion resistance for four of the alcohols after 3 days in the dark. In addition, Table VI (2).…”

Section: Resultsmentioning

confidence: 99%

The Influence of Aliphatic Alcohols on Leaf Senescence

Satler¹,

Thimann²

1980

Plant Physiol.

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Because of the effects of ethanol used as a solvent in other experiments, the action of aliphatic alcohols on leaf senescence in the dark has been studied systematically. These compounds both maintain chlorophyll and prevent proteolysis in the dark, much as do the cytokinins and other senescence-delaying substances. The activity of the straight-chain alcohols increases in a log-linear fashion with increasing chain length up to 1-octanol. Introduction of a branch in the chain or of a second OH group greatly decreases, or in some cases annuls, the antisenescence activity. In all cases, the action on senescence is closely (although not always exactly) paralleled by opening of the stomata. Abscisic acid and exposure to high concentrations of osmoticum, both of which close the stomata, antagonize the action of the alcohols. Some interactions with other agents are noted. The effects are compared with reported effects on seed germination, on hemolysis and animal membranes, and especially on permeability to K' ions, and a tentative basis for the mechanism of action is advanced.The ability of a number of chemically unrelated compounds to exert striking modifications of the progress of senescence in the detached leaves of oat seedlings has been reported elsewhere (22,24, and literature cited therein). Besides the cytokinins, at least five different compounds act to delay senescence in the dark, whereas three, as well as two physical treatments, promote the slower rate of senescence in the light, thus antagonizing the delaying effect of light. We found that in all cases the action on senescence was paralleled by an action on the stomatal aperture; stomatal closure paralleled promotion of senescence and stomatal opening paralleled its delay or inhibition.In studying these effects, it was necessary on several occasions to use alcohol as a solvent. Although the ethanol was diluted down to a maximum of 1% before application of the solution to the leaves, we noted that controls floated on this aqueous alcohol in darkness behaved very differently from those floated on H20. An example, with two concentrations of ethanol, is shown in Table I. Figures I and 2 of reference 24 also showed alcohol effects, but these were superimposed on the effects of FC2. It is clear from these data that ethanol exerts an effect on senescence in darkness like that of the several senescence inhibitors, although more weakly. Repeated observations of this alcohol effect led to a study of the action of a number of aliphatic alcohols on senescence. In this paper we report the considerable activity of a series of aliphatic alcohols in preventing or delaying leaf senescence in the dark. Disappearance of Chl and proteolysis responded similarly in all cases examined. The relation between structure and activity 'This work was supported in part by Grant BMS 7683126 from the National Science Foundation (to K. V. T.).2 Abbreviations: FC: fusicoccin; CCCP: carbonyl cyanide m-chlorophenylhydrazone. among the alcohols is closely parallel to reported effects...

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“…Table V shows the diffusion resistance for four of the alcohols after 3 days in the dark. In addition, Table VI (2).…”

Section: Resultsmentioning

confidence: 99%

The Influence of Aliphatic Alcohols on Leaf Senescence

Satler¹,

Thimann²

1980

Plant Physiol.

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“…9). The exudate from the cold-grown plants was much more dilute in the 10 than the 25 C series. This difference was most dramatic at the lower pressures, and was apparent though not significant at the higher pressures.…”

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“…Such changes alter membrane permeability and enzyme activity (8,10,19). Arrhenius plots were used by Clarkson (2) to study exudation rates and ion concentration of the xylem exudate from excised barley and rye roots preconditioned at various temperatures.…”

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Effect of Temperature on Water and Ion Transport in Soybean and Broccoli Systems

et al. 1979

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Steady-state flow rates and exudate osmotic potentials were measured from complete root systems from warm-(28/23 C) or cold-(17/11 C) grown soybean or broccoli (Brassica oleracea) plants at various pressures or different temperatures.In warm-grown soybean roots systems, a break occurred at 14.7 C in the Arrhenius plot of total flow at constant pressure. When plants were grown at lower temperatures, the break point shifted to 8 C. Broccoli, a chileing-resistant species, showed no break for the temperature range used, but cooler growth temperatures decreased the activation energy for water flow through the root system from 18 kilocalories per mole to 9 kilocalories per mole. In both broccoli and soybean, cold-grown plants had lower exudate potentials and greater flow rates at low hydrostatic pressures than the warm-grown plants.These observations indicate that the rate-limiting site for passive water transport is a membrane which may be modified as the plant acclimates to varying growth temperatures. An additional part of the acclimation process is an increase in activity of root ion pumps.Since the time of Hales (1727) it has been known that cold soil reduces the absorption of water by plants. Differences among species in reaction to water absorption at low temperatures were reviewed by Kramer (1 1). Kuiper (13) was among the first to note that at a "critical" temperature, which varied with the temperature at which roots were grown, a sharp drop occurred in water absorption. Some investigators attributed anomalies such as this to discontinuities in properties of surface water at 15, 30, 45, and 60 C (7, 15, 18).A more likely hypothesis attributes sharp breaks in Arrhenius plots of biological phenomena to phase transitions in membrane lipids in which the hydrophobic core changes from a liquid to a solid or crystalline state at some specific temperature. Such changes alter membrane permeability and enzyme activity (8,10,19). Arrhenius plots were used by Clarkson (2) to study exudation rates and ion concentration of the xylem exudate from excised barley and rye roots preconditioned at various temperatures. With rye roots grown at 20 C he found a break in the Arrhenius plot of exudation rate versus temperature at 10 C, but for roots preconditioned at 8 C for 3 days the break occurred at 5 C.

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“…Cram and Pitman (3) reported that ABA did not change the hydraulic conductivity of maize or barley roots, but Glinka and Reinhold (9,10) reported that ABA increased both the diffusional permeability and hydraulic conductivity of roots to water flow under a pressure of 0.8 bar. Most recently, ABA was reported to have no effect on osmotically driven water flow in excised sunflower roots (4).…”

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Effect of Abscisic Acid on Root Hydraulic Conductivity

Markhart¹,

Fiscus²,

Naylor³

et al. 1979

Plant Physiol.

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Reports of the effects of abscisic acid (ABA) on ion and water fluxes have been contradictory. Some of the confusion seems due to the interaction of ion and water transport across membranes. In these experiments root systems were subjected to hydrostatic pressures up to 5.0 bars to enable measurement of root conductance that was independent of measurement of osmotic potentials or ion fluxes.ABA between 5 x 10-I molar and 2 x 10' molar resulted in a decrease in the conductance of the soybean root systems as compared with the controls. ABA treatment also eliminated the discontinuity in the Arrhenius plot of total flow versus reciprocal temperature at constant pressure. The results suggest that ABA acts at the membrane that is rate-limiting to water flow directly, or by altering metabolism that in turn affects the membrane.The dramatic increase in ABA content in stressed plants (20,23) (12) found that ABA stimulated ion uptake in Phaseolus roots, whereas Erlandsson and co-workers (4) observed a decrease in "Rb uptake in sunflower roots.Cram and Pitman (3) reported that ABA did not change the hydraulic conductivity of maize or barley roots, but Glinka and Reinhold (9, 10) reported that ABA increased both the diffusional permeability and hydraulic conductivity of roots to water flow under a pressure of 0.8 bar. Most recently, ABA was reported to have no effect on osmotically driven water flow in excised sunflower roots (4). Pitman and Wellfare (18) found dramatic decreases in barley root exudation rates treated with ABA, but concluded that this was due to an inhibition of active salt transport and not hydraulic conductivity. ' Research supported by National Science Foundation Grants PCM76-11 142-AO1-2 to Dr. P. J. Kramer and DEB77-15845 These contradictions could be due to the difficulty in evaluating a complex transport system as a root. The standing osmotic gradient (I) and the removal of ions from the ascending xylem water (13) make determination of the osmotic driving force for water flow difficult. At low hydrostatic pressures the interaction between osmotic and hydrostatic driving forces makes it impossible to assess whether a change in flow rate is due to a change in hydraulic conductivity or ion movement (6). The analytical technique of Fiscus (6) provides a method of measuring the hydraulic conductance (L)5 of a root system independent of ion transport.The experiments reported here use applied hydrostatic pressures to determine the effect of ABA on water flux through root systems, to determine if changes in flux are due to changes in L and to determine the nature of the changes ABA induces in the ratelimiting barrier to water flux. MATERIALS AND METHODSCulture conditions and basic experimental procedures have been previously described (15). Soybean plants were grown in a half-strength Hoagland nutrient solution under a 14-h photoperiod and a thermoperiod of 28/23 C. Root systems of decapitated plants were sealed in a 10.3-liter pressure chamber filled with fresh nutrient solution. Hydrostatic pres...

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Induced Changes in Permeability of Plant Cell Membranes to Water

Cited by 54 publications

References 16 publications

The Influence of Aliphatic Alcohols on Leaf Senescence

The Influence of Aliphatic Alcohols on Leaf Senescence

Effect of Temperature on Water and Ion Transport in Soybean and Broccoli Systems

Effect of Abscisic Acid on Root Hydraulic Conductivity

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