Stomatal Opening in Isolated Epidermal Strips of <i>Vicia faba</i>. I. Response to Light and to CO<sub>2</sub>-free Air

Fischer, Ronald P.

doi:10.1104/pp.43.12.1947

Cited by 86 publications

(65 citation statements)

References 15 publications

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“…2, A and B) hydroactive. Depending on whether final apertures are compared to apertures at 0-time or to those measured after a 5 h incubation in the dark, changes in guard cell osmotic potentials ranged between -0.08 and -0.13 MPa um-' of aperture, in good agreement with published data (4,5,7,14). Despite this decrease in osmotic potential, histochemical analysis showed that no detectable amounts of K+ had entered the guard cells, and there was no indication of starch hydrolysis, which is required for the supply of carbon skeletons supporting malate synthesis.…”

Section: Discussionsupporting

confidence: 77%

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Light Quality and Osmoregulation in Vicia Guard Cells

Tallman¹,

Zeiger²

1988

Plant Physiol.

110

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Osmoregulation in opening stomata of epidermal peels from Vicia faba L. leaves was investigated under a variety of experimental conditions. The K+ content of stomatal guard cells and the starch content of guard cell chloroplasts were examined with cobaltinitrite and iodine-potassium iodide stains, respectively; stomatal apertures were measured microscopically. Red light (50 micromoles per square meter per second) irradiation caused a net increase of 3.1 micrometers in aperture and a decrease of -0.4 megapascals in guard cell osmotic potential over a 5 hour incubation, but histochemical observations showed no increase in guard cell K+ content or starch degradation in guard cell chloroplasts. At Recent characterization of a blue light-dependent proton pump at the guard cell plasmalemma has linked light perception with the activation of ion transport mechanisms providing guard cells with the capacity for a quantitative transduction of prevailing light fluences into adequate ionic uptake for osmoregulation (2, 37). In addition to the blue light photosystem, guard cells also possess Chl in their chloroplasts, which acts as a separate photoreceptor to induce stomatal opening (9,12,33). Blue lightinduced stomatal opening is the result of combined responses of the two photoreceptor systems. Blue light-dependent opening has been correlated with proton pumping (2, 37), K' uptake (12), starch degradation (22), and malate biosynthesis (23). In Vicia faba, blue light-dependent opening in epidermal peels saturates at 25 umol m-2 s-', is inhibited by KCN but not by DCMU at intensities 0Iusmol m-2 s-', and is partially sensitive to DCMU at intensities 225 umol m-2 s-' (33). Red light-induced stomatal opening relies on sensory transduction mediated by Chl. In Vicia, red light-dependent stomatal opening in peels saturates at 50 ,umol m-2 s-, is insensitive to KCN, and is completely inhibited by DCMU (33). Red light-induced stomatal opening has been correlated with oxygen evolution and photophosphorylation (36,38) and with synthesis of intermediates of the PCRP3 (11).The interconversion of photosynthetically produced sugars and starch was a fundamental hypothesis of stomatal movements that dominated plant physiology p6rior to its abandonment in favor of the K+ hypothesis (16,21

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Section: Discussionsupporting

confidence: 77%

“…In normal air, 35 to 60% of stomata contained K+, with maximum levels of K+ seen at 1 to 3 h of incubation. It is noteworthy that in most of the previous studies, K+ content was analyzed after 3 h of incubation (4,5,12,13). In C02-free air, a maximum of 40% of the guard cells showed K+ uptake at 3 and 5 h of incubation.…”

Section: Methodsmentioning

confidence: 99%

Light Quality and Osmoregulation in Vicia Guard Cells

Tallman¹,

Zeiger²

1988

Plant Physiol.

110

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“…Leaflets were cut off plants and carried to the laboratory abaxial surface upwards in darkened closed Petrie dishes containing a little water. Rectangular epidermal strips (~3 by 5 mm2) were taken from the abaxial surface ofleaflets !-2 hr later as described before (Fischer 1968) and immediately floated cuticle upwards on distilled water in the dark. Light or other experimental treatments commenced 15-30 min later.…”

Section: Methodsmentioning

confidence: 99%

“…Experiments usually studied the response of stomatal aperture to light plus C02-free air in epidermal strips floated on a range of solutions (but always without buffer, in contrast to Fischer 1968). Unless otherwise stated the chloride salts of potassium and calcium were used; solution pH ranged from 4 to 7 and temperature from 28 to 32°C without effect on responses.…”

Section: Methodsmentioning

confidence: 99%

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Aspects of Potassium Accumulation by Stomata of Vicla Faba

Fischer¹

1972

Aust. Jnl. Of Bio. Sci.

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Potassium accumulation by guard cells during the light opening of V. Jaba stomata in epidermal strips was determined quantitatively with 42K and 86Rb tracers. The sodium cobaltinitrite stain for potassium was also used. Particular attention was paid to errors arising from the presence of intact epidermal cells.When epidermal strips obtained from darkened leaves were floated on potassium chloride solution (usually 10 mM) in light plus C02-free air, guard cell potassium content and stomatal aperture increased in parallel, both approaching a maximum after about 300 min. Flux measurement suggested that the steady maximum potassium content (and aperture) arises because of a decline in the initially high potassium influx. With opening of stomata in the light, external calcium reduced in a parallel manner both opening and potassium uptake at potassium concentrations ranging from nearly zero to 50 mM. Also, maximum stomatal opening and potassium accumulation in the presence or absence of calcium bore linear relationships to log external potassium concentration. These results are discussed in relation to potassium accumulation in other plant systems.In experiments with epidermal strips, guard cell potassium content showed a consistent linear relationship to stomatal aperture. For 16 experiments spanning two years and many treatments affecting aperture, the mean slope of this relationship was 2·6 nmoles cm-2 p.m-l. This is equivalent to a change in potassium concentration of 40 mM p.m-l. The increase in guard cell osmotic pressure attributable to potassium plus anion accumulation is estimated to be 1·5 bars p.m-l, which is a major portion of the observed increase in osmotic pressure with opening (2, 0 bars p.m-l).

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