The Effect of Temperature on Opening of the Stomatal Cells

Abstract

The effcfl of loiupenitiire on the stoinntjtl nioveim'nls lias been studied by about ten different workers (iiiriu}^ the p;ist 40 years. Some of the.se mveslij,'ations -amon^ them one oC mine iStaUeit H(28) -were made early in tbis period, al a time when it was not known that the movements are sensitive even to small water deficits in the leaves, and to sUj^ht chanj,'es in the (X)j content of the air. (Consequently, the experiments were made under conditions that may bave given rise In a water deficit, and to chanfjes in the C();> iu the object chamber. Tbe openiri}.; movements whose temperature-dependence was studied were, therefore, probahly not of a phot(.)active nature only. This ciin explain the discrepancies between the results reported (for a review of the literature, see Slalfelt ]\)i)Vi. ]). ;(7."t).Actually, a tempenifure effect has been definitely established only in one investii^atiou by I.ntlfield (1921), and in one by Wilson (1948). it is not, bowever. apparent from the experiments wbether Ibis eftect was manifested ill phutoiictive opening alone, fir whether it was localized to opening processes of other kinds as well.Loitfield used wetl watered pot plants of alfalfa as the experimental object. After the plants had been kept in darkness i)vernight. they were exposed to daylight in the open air. and to other climatic laetors operative there. Stomatal opening was followed microseopically (Lloyd's method) during the first hours. I he experiments were repeated on days with different temperature. Despite the variable external conditions, a distinct relation was observed l)etween temperature and stomatal opening. Tbus. at 10°C approximately 4 bours were retpiired to reach maximum opening. "At 20°C slightly less ih:ni 2 hours was required, and at 30^ (^ nearly an hour. The bighest ti-mperattire. 34""C. caused complete opening in less than 50 minutes. At freezing and alxiut 40°C, opening does not occur or is very erratic" (p. 57).The definite results obtained in Loftiield's experiments are presumably Phusiol. Plant.. /.>. ;.W2 Phyxlol. Plant.. 15. IW2 [772J

Unexpected Connections between Humidity and Ion Transport Discovered Using a Model to Bridge Guard Cell-to-Leaf Scales

“…OnGuard2 faithfully reproduced the experimentally determined kinetics and dependence of stomatal aperture and g s on VPD and water availability, notably a weak dependence on VPD unless water delivery to the leaf was limited; it replicated the curvilinear effects of leaf temperature on aperture and g s (Supplemental Figure 1) previously reported across a range of species in the literature (Wilson, 1948;Stalfelt, 1962;Farquhar and Sharkey, 1982;Spence et al, 1984;Urban et al, 2017); it showed the opposing changes in guard cell osmolarity and turgor (Figure 2) expected of a unified framework equating VPD to extracellular osmotic potential; and it recapitulated previously published data of enhanced Mal synthesis and accumulation with osmotic stress (Asai et al, 1999(Asai et al, , 2000. Noteworthy to these predictions, within OnGuard2 it is the change in water potential of the apoplast around the guard cell with a VPD step that drives water flux across the guard cell plasma membrane, thereby affecting guard cell volume, the free concentration of solute within the guard cell, and engaging changes in ion transport and metabolism (Figure 8).…”

“…The model also demonstrated a dependence on temperature (Supplemental Figure 1) that is broadly consistent with the curvilinear relationships previously reported for stomatal aperture across a number of species (Wilson, 1948;Stalfelt, 1962;Spence et al, 1984;Willmer and Fricker, 1996;Urban et al, 2017).…”

Histochemical Approach to Properties of Vicia faba Guard Cell Phosphoenolpyruvate Carboxylase

“…1) may partially explain the rapid decrease in stomatal aperture in Vicia above 35 C (17). The effects of temperature on stomatal opening are complex, of course, and would not be explained by the response of this one enzyme alone.…”

THE EFFECT OF BENTAZONE ON STOMATAL BEHAVIOUR IN CHENOPODIUM ALBUM L.

“…2), since the general consensus of opinion (e.g. Stalfelt, 1962;Willmer and Mansfield, 1970) is that stomatai opening is mediated by an active process, requiring an energy source. One would assume, therefore, that higher temperatures would result in a greater degree of opening.…”