Tag: Beyschlag W.

Effects of humidity during diurnal courses on the CO2– and light-saturated rate of net CO2 uptake in the sclerophyllous leaves of Arbutus unedo

Lange O. L., Tenhunen J. D.², Beyschlag W., (1985)

  • 1 Lehrstuhl für Botanik II, Universität Würzburg, Mittlerer Dallenbergweg 64, D-8700, Würzburg, Federal Republic of Germany.
  • 2 Systems Ecology Research Group, San Diego State University, 92182, San Diego, CA, USA.
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Oecologia (Berlin) 67: 301–304 – PMID: 28311330 – DOI: 10.1007/BF00384305 –

https://pubmed.ncbi.nlm.nih.gov/28311330/

No abstract available

Limitations in leaf CO2 uptake rates due to photosynthetic capacity, carboxylation efficiency, and stomatal conductance

Changes during summer drought in leaf CO2 uptake rates of macchia shrubs growing in Portugal: Limitations due to photosynthetic capacity, carboxylation efficiency, and stomatal conductance

by Tenhunen J. D., Beyschlag W., Lange O. L., Harley P. C. (1987)

Systems Ecology Research Group, San Diego State University, San Diego,
California, 92182 USA

In E. Zeiger, G. D. Farquhar, & I.R. Cowan (Eds.), Stomatal function (pp. 323–351). Stanford, CA: Stanford University Press – In: Tenhunen, J.D., Catarino, F.M., Lange, O.L., Oechel, W.C. (Eds.), Plant Response to StressFunctional Analysis in Mediterranean Ecosystems. NATO ASI Ser. G, vol. 15. Springer, pp. 305e327. –

https://doi.org/10.1007/978-3-642-70868-8_18 –

https://link.springer.com/chapter/10.1007/978-3-642-70868-8_18

Midday stomatal closure and midday depression of net CO2 exchange of leaves

Changes in photosynthetic capacity, carboxylation efficiency, and CO2 compensation point associated with midday stomatal closure and midday depression of net CO2 exchange of leaves of Quercus suber

by Tenhunen J. D., Lange O. L., Gebel J., Beyschlag W., Weber J. A. (1984)

Lehrstuhl für Botanik II der Universität, Mittlerer Dallenbergweg 64, D-8700, Würzburg, Germany.

J. A. Weber, Biological Station, University of Michigan, Ann Arbor, USA

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In Planta 162: 193-203 – doi: 10.1007/BF00397440. –

https://www.ncbi.nlm.nih.gov/pubmed/24253090

Abstract

The carbon-dioxide response of photosynthesis of leaves of Quercus suber, a sclerophyllous species of the European Mediterranean region, was studied as a function of time of day at the end of the summer dry season in the natural habitat.

To examine the response experimentally, a “standard” time course for temperature and humidity, which resembled natural conditions, was imposed on the leaves, and the CO2 pressure external to the leaves on subsequent days was varied.

The particular temperature and humidity conditions chosen were those which elicited a strong stomatal closure at midday and the simultaneous depression of net CO2 uptake. Midday depression of CO2 uptake is the result of

i) a decrease in CO2-saturated photosynthetic capacity after light saturation is reached in the early morning,

ii) a decrease in the initial slope of the CO2 response curve (carboxylation efficiency), and

iii) a substantial increase in the CO2 compensation point caused by an increase in leaf temperature and a decrease in humidity.

As a consequence of the changes in photosynthesis, the internal leaf CO2 pressure remained essentially constant despite stomatal closure. The effects on capacity, slope, and compensation point were reversed by lowering the temperature and increasing the humidity in the afternoon. Constant internal CO2 may aid in minimizing photoinhibition during stomatal closure at midday.

The results are discussed in terms of possible temperature, humidity, and hormonal effects on photosynthesis.

Stomatal patchiness

 

Towards a Causal Analysis of Stomatal Patchiness. The Role of Stomatal Size Variability and Hydrological Heterogeneity

by Beyschlag W.,bey

Eckstein J. (2001)

in Acta Oecologica, Vol. 22, No. 3, 2001, pp. 161-173. –

http://dx.doi.org/10.1016/S1146-609X(01)01110-9

Abstract

The induction of the well known and widespread phenomenon ‘stomatal patchiness’ has been attributed to a variety of potential causes: from low PPFD levels, all kinds of stress conditions to CO2-changes and even fungal infections.

A mechanism which explains the occurrence of reproducible patterns of static (i.e. stable) stomatal patchiness at low PPFD levels is proposed. Further, experimental evidence is presented for the hypothesis that dynamic (i.e. not stable) stomatal patchiness is a consequence of heterogeneous water status in different parts of the leaf and can be induced by all ambient factors which cause such heterogeneities.

Stomatal patchiness in leaves

Photo credit: Google

Xanthium strumarium

Changes in photon flux can induce stomatal patchiness

by Eckstein J., Beyschlag W., Mott K. A., Ryel R. J. (1996)

in Plant, Cell and Environment19,1066–1074. 

CrossRef, Abstract, PDF(9071K), References,

Abstract

Images of chlorophyll fluorescence were used to detect the occurrence of stomatal patchiness in leaves from eight species under variable photon flux conditions.

Pronounced stomatal patchiness was induced within 5–10 min after PFD was changed from intermediate (∼450 μmol quanta m−2 s−1) to low (∼150 μmol quanta m−2 s−1) levels. This effect was completely reversible by returning PFD to intermediate levels.

The pattern of heterogeneous fluorescence for each leaf was usually similar during repeated applications of medium and low PFD. In three species, stomatal patchiness could only be induced in slightly water-stressed plants.

Leaves of more severely water-stressed Xanthium strumarium plants in low air humidity exhibited oscillations in fluorescence that corresponded with oscillatory changes in leaf diffusion conductance for water vapour.

Stomatal patchiness was also induced by illuminating dark-adapted leaves with low PFD (below 200–300 μmol quanta m−2 s−1).

Infiltration of leaves with distilled water showed that heterogeneous chlorophyll fluorescence was caused by changes in stomatal apertures.

Abstract: Wiley

Read the full article: Wiley

Stomatal patchiness in sclerophylls

STOMATAL PATCHINESS IN MEDITERRANEAN EVERGREEN SCLEROPHYLLS – PHENOMENOLOGY AND CONSEQUENCES FOR THE INTERPRETATION OF THE MIDDAY DEPRESSION IN PHOTOSYNTHESIS AND TRANSPIRATION

by Beyschlag W., Pfanz H., Ryel R. J. (1992)

in Planta187: 546–553.

Abstract

Midday depression of net photosynthesis and transpiration in the Mediterranean sclerophylls Arbutus unedo L. and Quercus suber L. occurs with a depression of mesophyll photosynthetic activity as indicated by calculated carboxylation efficiency (CE) and constant diurnal calculated leaf intercellular partial pressure of CO2 (C(i)). This work examines the hypothesis that this midday depression can be explained by the distribution of patches of either wide-open or closed stomata on the leaf surface, independent of a coupling mechanism between stomata and mesophyll that results in a midday depression of photosynthetic activity of the mesophyll. Pressure infiltration of four liquids differing in their surface tension was used as a method to show the occurrence of stomatal patchiness and to determine the status of stomatal aperture within the patches. Liquids were selected such that the threshold leaf conductance necessary for infiltration through the stomatal pores covered the expected diurnal range of calculated leaf conductance (g) for these species. Infiltration experiments were carried out with leaves of potted plants under simulated Mediterranean summer conditions in a growth chamber. For all four liquids, leaves of both species were found to be fully infiltratable in the morning and in the late afternoon while during the periods leading up to and away from midday the leaves showed a pronounced patchy distribution of infiltratable and non-infiltratable areas. Similar linear relationships between the amount of liquid infiltrated and g (measured by porometry prior to detachment and infiltration) for all liquids clearly revealed the existence of pneumatically isolated patches containing only wide-open or closed stomata. The good correspondence between the midday depression of CE, calculated under the assumption of no stomatal patchiness, and the diurnal changes in non-infiltratable leaf area strongly indicates that the apparent reduction in mesophyll activity results from assuming no stomatal patchiness. It is suggested that simultaneous responses of stomata and mesophyll activity reported for other species may also be attributed to the occurrence of stomatal patchiness. In Quercus coccifera L., where the lack of constant diurnal calculated C(i) and major depression of measured CE at noontime indicates different stomatal behavior, nonlinear and dissimilar relationships between g and the infiltratable quantities of the four liquids were found. This indicates a wide distribution of stomatal aperture on the leaf surface rather than only wide-open or closed stomata.

See the text: Web of Science