Watering leads to stomatal closure at first, with decreased rates of photosynthesis and transpiration, but subsequently leaf resistance diminishes and the rates increase as normal turgor relations in the leaf re-establish

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浇水初期会导致气孔关闭，光合作用和蒸腾速率降低，但随后叶片阻力减小，速率恢复正常，因为叶片内部的正常渗透关系重新建立起来。

Inicialmente, a irrigação leva ao fechamento dos estômatos, com taxas reduzidas de fotossíntese e transpiração, mas posteriormente a resistência das folhas diminui e as taxas aumentam à medida que as relações normais de turgor na folha são restabelecidas.

El riego conduce al cierre estomático al principio, con tasas reducidas de fotosíntesis y transpiración, pero posteriormente la resistencia de las hojas disminuye y las tasas aumentan a medida que se restablecen las relaciones normales de turgencia en la hoja.

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STOMATAL BEHAVIOUR IN RELATION TO RATES OF PHOTOSYNTHESIS AND TRANSPIRATION IN PELARGONIUM

Willis A. J., Balasubramaniam S. (1968)

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New Phytologist 67(2): 265-285 – https://doi.org/10.1111/j.1469-8137.1968.tb06383.x –

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-8137.1968.tb06383.x

Summary

An experimental procedure is described by which contemporaneous assessments of leaf resistance, rates of transpiration and of carbon dioxide exchange can be made on attached leaves. The relative humidity and carbon dioxide concentration of an air stream flowing into a leaf chamber are controlled, and of the outflowing stream monitored. The effects of light intensity and of water relations of the leaf were investigated with reference to leaf resistance and rates of transpiration and photosynthesis. In Pelargonium × hortorum quick stomatal opening in response to illuminatioxi was observed in plants which were not under water stress. On illumination of darkened leaves the rates of transpiration and photosynthesis were shown to rise rapidly, bearing a relation to leaf resistance, and indicating stomatal control of these processes. Over long periods of illumination water deficits develop, leaf resistance increases and rates of transpiration and photosynthesis decline. Typical findings of the levels of leaf resistance at a range of light intensities, and the corresponding values of transpiration rate and photosynthetic rate, are given.

The overriding importance of water deficit in influencing stomatal behaviour in leaves under substantial water stress is shown in a series of experiments. When water deficits are fairly small, the stomata of leaves open in response to illumination, but more slowly than those of leaves of well-watered plants; in leaves under water stress stomatal closure is also much accelerated on darkening. Under moderate water deficits, the stomata of leaves may open in response to light, but close again fairly quickly as the stress increases. Changes in rates of transpiration and photosynthesis parallel closely those of leaf resistance under these conditions. The effect of watering plants under water stress on leaf resistance and rates of gaseous exchange is shown in two experiments. The results indicate that watering leads to stomatal closure at first, with decreased rates of photosynthesis and transpiration, but subsequently leaf resistance diminishes and the rates increase as normal turgor relations in the leaf re-establish. Stomatal behaviour and control of rates of transpiration and photosynthesis are discussed, and the water relations of the leaf shown to be of critical importance in this connection.

Stomatal movements and changes of carbohydrate

Stomatal movements and changes of carbohydrate in leaves of Chrysanthemum maximum

Yemm E. W., Willis A. J. (1954)

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New Phytologist 53: 373-396 – https://doi.org/10.1111/j.1469-8137.1954.tb05248.x –

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-8137.1954.tb05248.x

Chlorophyll and Photosynthesis in Stomatal Guard Cells

Yemm E. W., Willis A. J. (1954)

Nature 173: 726 – https://doi.org/10.1038/173726a0 –

https://www.nature.com/articles/173726a0#citeas

Abstract

INVESTIGATIONS in this laboratory carried out by different techniques from those of Shaw and MacLachlan give direct support to their recent statements¹ with regard to the presence of chlorophyll in stomatal guard cells and the ability of these cells to assimilate carbon dioxide by photosynthesis.

Measurements of light absorption made on intact plastids in the living guard cells of leaves of Rumex patientia, Chrysanthemum maximum and Vicia faba have shown the presence of chlorophylls a and b.

Moreover, an active synthesis of carbohydrates in the light is clearly indicated by the diurnal changes of sugars and starch in the epidermis of the leaf.

Stomatal movements and rates of gaseous exchange in excised leaves

Stomatal movements and rates of gaseous exchange in excised leaves of Vicia faba

by Balasubramaniam S., Willis A. J. (1969)

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In New Phytol. 68: 663–674 – https://doi.org/10.1111/j.1469-8137.1969.tb06470.x –

https://nph.onlinelibrary.wiley.com/doi/abs/10.1111/j.1469-8137.1969.tb06470.x

Abstract

Simultaneous measurements of leaf resistance to gaseous flow, rate of transpiration and rate of carbon dioxide exchange were made with the main object of investigating the effects of severing the petiole on stomatal movements and gaseous exchange of leaves of Vicia faba of differing initial water content.

Extensive stomatal changes occurred on cutting the petioles of illuminated leaves in air. The magnitude and direction of the stomatal movements were strongly influenced by the water relations of the leaf at the time of excision.

When the water deficit was small there was a substantial temporary stomiatal opening and corresponding temporary increases in rates of transpiration and photosynthesis. In leaves of moderate water deficit the stomatal opening on leaf excision was much less pronounced and, in leaves under severe water stress at he time of cutting, there was little evidence of any immediate stomatal response.

Preliminary stomatal opening and a temporary increase in transpiration rate were also observed in leaves excised in air from plants kept in darkness. In experiments in which the illuminated leaves were severed under water, however, a temporary increase of leaf resistance to gaseous flow was found on leaf excision, and associated declines in rates of transpiration and of photosynthesis.

The changes in transpiration rate resulting from leaf severance are clearly associated with stomatal behaviour, and there is evidence of close stomatal control, under these conditions, of rates of transpiration and of photosynthesis.

The phenomena involved in leaf excision both in air and under water are discussed and stomatal behaviour shown to depend to a considerable extent on the water relations of the leaf; stomatal movements are interpreted largely in terms of differential turgor changes in the guard cells and neighbouring epidermal cells.