Cyclic Variations in Stomatal Aperture, Transpiration, and Leaf Water Potential Under Constant Environmental Conditions

Barrs, H. D.

doi:10.1146/annurev.pp.22.060171.001255

Cited by 128 publications

(109 citation statements)

References 0 publications

Supporting

Mentioning

104

Contrasting

Order By: Relevance

“…2, 5, 6, 8) but these peaks did not appear consistently and did not represent a consistent period when they did appear. Because of this inconsistency, interpretation of the short-period MESA peaks is difficult, but it is possible that they may relate to reported short-period stomatal oscillations in whole leaves (2).…”

Section: Discussionmentioning

confidence: 99%

Circadian Stomatal Rhythms in Epidermal Peels from Vicia faba

Gorton¹,

Williams²,

Binns³

et al. 1989

Plant Physiol.

View full text Add to dashboard Cite

Circadian rhythms in stomatal aperture and in stomatal conductance have been observed previously. Here we investigate circadian rhythms in apertures that persist in functionally isolated guard cells in epidermal peels of Vicia faba, and we compare these rhythms with rhythms in stomatal conductance in attached leaves. Functionally isolated guard cells kept in constant light display a rhythmic change in aperture superimposed on a continuous opening trend. The rhythm free-runs with a period of about 22 hours and is temperature compensated between 20 and 300C. Functionally isolated guard cell pairs are therefore capable of sustaining a true circadian rhythm without interaction with mesophyll cells. Stomatal conductance in whole leaves displays a more robust rhythm, also temperature-compensated, and with a period similar to that observed for the rhythm in stomatal aperture in epidermal peels. When analyzed individually, some stomata in epidermal peels showed a robust rhythm for several days while others showed little rhythmicity or damped out rapidly. Rhythmic periods may vary between individual stomata, and this may lead to desynchronization within the population. Stomata function to control CO2 uptake and transpirational water loss, and they are closely regulated by such factors as light (for review see 23, 28), RH (for review see 22), and carbon dioxide concentration (for review see 17). In addition to environmental factors, stomata are controlled by an endogenous circadian clock. This control may appear as a rhythmic change in aperture under constant conditions (15,21) or as a rhythmic change in sensitivity to some environmental factor; light has been studied most frequently (4, 5, 15). Here we are concerned only with the first type of endogenous control: simple, free-running rhythmicity in stomatal aperture. A wide variety of plant species show such free-

show abstract

Section: Discussionmentioning

confidence: 99%

Circadian Stomatal Rhythms in Epidermal Peels from Vicia faba

Gorton¹,

Williams²,

Binns³

et al. 1989

Plant Physiol.

View full text Add to dashboard Cite

show abstract

“…Cyclic stomatal behaviour has been observed in many species, including cotton, pepper and sunflower (Barrs & Klepper, 1968), citrus trees (Levy & Kaufmann, 1976), rose bushes (Rose & Rose, 1994) and grapevines (Düring, 2000;Düring & Stoll, 1996). These oscillations can be the result of instability in either a CO 2 control system or a water control system, or a combination thereof (Barrs, 1971). The period of oscillation can vary from less than one minute to more than an hour.…”

Section: Methodsmentioning

confidence: 99%

“…The period of oscillation can vary from less than one minute to more than an hour. Shallow, shorter oscillation periods are generally associated with control of CO2 status, whereas deeper, longer periods are associated with water status control (Barrs, 1971 and references therein). The generally accepted explanation is the following: as stomata open in the light, transpiration increases, leaf water content falls, and the associated water deficit causes partial stomatal closure, leaves regain turgor upon water inflow in response to the steepened water potential gradient, and finally Ψl rises again, permitting stomata to re-open, thus re-commencing the cycle (Barrs & Klepper, 1968).…”

Section: Methodsmentioning

confidence: 99%

Water Relations of Vitis vinifera L. cv. Sunred Seedless in Response to Soil Water Depletion Before Harvest

Myburgh

Howell

2017

SAJEV

View full text Add to dashboard Cite

“…

ABSTRACTIt is supposed that oscillations in stomatal conductance are associated with the dynamic properties of the loop in which rate of evaporation affects, through physiological processes, Self-sustained oscillations, having a period of about 40 min, in stomatal aperture, and plant functioning associated with stomatal aperture, are known to occur in many plant species (1,3). Several models of the mechanism responsible for these oscillations have been described (3, 7-9, 1 1).

…”

mentioning

confidence: 99%

“…Self-sustained oscillations, having a period of about 40 min, in stomatal aperture, and plant functioning associated with stomatal aperture, are known to occur in many plant species (1,3). Several models of the mechanism responsible for these oscillations have been described (3, 7-9, 1 1).…”

mentioning

confidence: 99%

Oscillations in Stomatal Conductance

Farquhar

Cowan²

1974

Plant Physiol.

View full text Add to dashboard Cite

It is supposed that oscillations in stomatal conductance are associated with the dynamic properties of the loop in which rate of evaporation affects, through physiological processes, Self-sustained oscillations, having a period of about 40 min, in stomatal aperture, and plant functioning associated with stomatal aperture, are known to occur in many plant species (1,3). Several models of the mechanism responsible for these oscillations have been described (3, 7-9, 1 1). They have in common one basic assumption: that the oscillations are due to the properties of the loop in which rate of evaporation affects, through physiological processes, the aperture of stomata and stomatal aperture in turn affects rate of evaporation. The models differ in the way they describe the physiological processes. The model described by Cowan (3) suggests itself: can we manipulate the total gain of the loop in an unambiguous way and show that the stability of the stomatal mechanism is affected in the manner expected? Any attempt to alter the characteristics of the physiological component of the loop would fall short of what is required because it would presume a detailed understanding of the processes involved. On the other hand, the environmental component of loop gain, which is the sensitivity of rate of evaporation to change in stomatal aperture, can be readily manipulated in a way which is unequivocal because the physical process involved is well understood. We report here on two experiments in which environmental gain has been altered and the effects on the stability of the stomatal mechanism have been observed. MATERIALS AND METHODSThe plants used were cotton (Gossypiumn hirsutum L. cv.Deltapine Smooth Leaf), 1 month old, having five or six leaves with a total area of 0.05 to 0.06 M2. The apparatus is described in detail elsewhere (6). In brief, it consists of a small closedcircuit wind tunnel. The working section, which contains the upper parts of the plant, is of Plexiglas and is illuminated from above by a xenon arc lamp. The flux of radiation is 80 w m-2 in the wavelength range 370 to 820 nm. Wind speed is about 1 m s-'. The stem of the plant is sealed in the floor of the working section, the roots below being immersed in aerated Hoagland solution.Ambient temperature is regulated, through the combination of a water-cooled heat exchanger and an electrical heater in the air stream approaching the plant, in such a way as to maintain the temperature of the leaves, rather than that of the air stream, as constant as possible. Thermojunctions (44 s.w.g. copper-constantan) are inserted into the main veins of three of the leaves, with the reference junctions in ice. The signals are continuously recorded on strip-chart; one is amplified and used to provide the error signal for proportional control of the electrical heating of the air stream. The bandwidth varies with thermal load, but is always less than 1 C. The humidity of the air stream is sensed by a dew-point hygrometer and is proportionally controlled by regulating the f...

show abstract

Cyclic Variations in Stomatal Aperture, Transpiration, and Leaf Water Potential Under Constant Environmental Conditions

Cited by 128 publications

References 0 publications

Circadian Stomatal Rhythms in Epidermal Peels from Vicia faba

Circadian Stomatal Rhythms in Epidermal Peels from Vicia faba

Water Relations of Vitis vinifera L. cv. Sunred Seedless in Response to Soil Water Depletion Before Harvest

Oscillations in Stomatal Conductance

Contact Info

Product

Resources

About