Stomatal conductance

Collatz, G. Ball, J. T., Grivet, C. and Berry, J. A. (1991). Physiological and environmental regulation of stomatal conductance, photosynthesis, and transpiration a model that includes a laminar boundary layer, Agric. For. Meteorol. 54,107-136. 

Collatz, G. J., Ribas-Carbo, M. and Berry, J. A. (1992). Coupled photosynthesis-stomatal conductance model for leaves of C4 plants, Aust.. Plant Physiol. 19,519-538. 

Photosynthesis and gas exchange of leaves are affected by many stresses including drought, flooding, salinity, chilling, high temperature, soil compaction and inadequate nutrition. Many, but not all, of these stresses have symptoms in common. For example, stomatal conductance and the rate of assimilation of CO2 per unit leaf area often decrease when stress occurs. Further, it is possible that several of the stresses may exert their effects, in part, by increasing the levels of the hormone abscisic acid (ABA) in the leaf epidermis. This hormone is known to close stomata when applied to leaves. 

Farquhar, G.D., Hubick, K.T., Terashima, I., Condon, A.G. Richards, R.A. (1987). Genetic variation in the relationship between photosynthetic CO2 assimilation rate and stomatal conductance to water loss. In Progress in Photosynthesis Research, Vol. IV, ed. J. Biggins, pp. 5 209-12. Dordrecht Martinus Nijhoff. 

Gollan, T., Passioura, J.B. Munns, R. (1986). Soil water status affects the stomatal conductance of fully turgid wheat and sunflower leaves. Australian Journal of Plant Physiology, 13, 459-64. 

Ward, D.A. Drake, B.G. (1988). Osmotic stress temporarily reverses the inhibitions of photosynthesis and stomatal conductance by abscisic acid - evidence that abscisic acid induces a localized closure of stomata in intact, detached leaves. Journal of Experimental Botany, 39, 147-55. 

Fig. 9. Leaf water potential and turgor, abaxial stomatal conductance, and ABA content of abaxial epidermis of leaves of Commelina plants which were grown with their root systems divided between two pots. Water was either applied daily to both halves of the root system (A) or was withheld from one half of the root system after day 1 of the experimental period (A). Points for water relations and conductance are means s.e. Modified from Zhang, Schurr Davies (1987).

Fig. 10. Leaf water potential and abaxial stomatal conductance (upper figure), and water potential and turgor of secondary and tertiary root tips (lower figure) of maize plants growing in 1 m deep soil columns, watered daily (A) or not watered after day 0(A). The roots were sampled from the upper 20 cm of the soil column. Plants were 20 days old at the beginning of the experimental period. Points are means s.e. Modified from Zhang Davies (1989).

Constitutive features of stomatal complexes which give a low stomatal conductance (e.g. sunken stomata, few stomata per unit leaf area). 

Adaptive features of stomata - rapid closure in response to turgor loss (and perhaps other stimuli) - which reduce transpiration when plants become stressed. Alternatively, for ephemer-als, maintenance of high stomatal conductance and photosynthetic capacity to permit maximum growth rate during the limited time that water is available. 

Soar, C. J., J. Speirs et al. (2004). Gradients in stomatal conductance, xylem sap ABA and bulk leaf ABA along canes of Vitis vinifera cv. Shiraz Molecular and physiological studies investigating their source. Fund. Plant Biol. 31(6) 659-669. 

The effect of zearalenone on crop development may be connected to its influence on the status and functioning of the photosynthetic apparatus (Koscielniak et al. 2008). The after-effects of zearalenone on the growth of soybean and wheat plants, net photosynthesis and transpiration rates, stomatal conductance, photochemical efficiency of photosystem 2 and on final seeds yield were determined. Modifications in leaf area were more pronounced in soybean than in wheat, and this tendency increases in successive developmental phases. The net photosynthesis was stimulated during the juvenile phase and during that of the final one by about 13.6% (average) in soybean plants. Stimulation of transpiration was also observed after... 

Jordan, F.L., Yoklic, M., Morino, K., Brown, P., Seaman, R., Glenn, E.P. Consumptive water use and stomatal conductance of Atriplex lentiformis irrigated with industrial brine in a desert irrigation district. Agric. For. Meteorol. 149(5), 899-912 (2009)... 

Figure 17.11 Neil Yorio at NASA s Kennedy Space Center taking leaf porometer measurements with potatoes to monitor stomatal conductance and transpiration rates. When measurements were taken at 400 ppm CO2, a mask was worn to removed exhaled breath from the chamber to avoid elevating the CO2 concentration.

Figure 17.12 Stomatal conductance of potatoes grown at 400, 1000, and 10 000 ppm carbon dioxide. Conductance and transpiration were lowest at 1000 ppm and highest at 10 000 ppm. Super-elevated concentrations like 10 000 ppm might can occur in closed environments in space (source Wheeler et al., 1999).

Wheeler, R. M, Mackowiak, C. L., Yorio, N. C., Sager, J. C. (1999). Effects ofC02 on stomatal conductance Do stomata open at very high CO2 concentrations Ann. Botany, 83, 243-251. 

Method. Whether to use stomatal density or stomatal index from leaf fossils for paleoelevation reconstruction depends on the availability of modern reference material and the quality of the fossil cuticle. Ideally both should be used on the same material to increase the confidence in the provided estimates. In cases, however, when the quality of the fossil cuticle does not allow epidermal cells to be recognized with the necessary accuracy, and stomatal index can not be determined, stomatal density measurements are the only available option. To use stomatal index, a training set of modem and herbarium material grown under different C02 pressure provides the necessary calibration. Because stomatal density is influenced by more factors than just the C02 partial pressure, the actual response of stomatal density of the chosen fossil taxon has to be confirmed by analyzing leaves from actual elevation transects. Stomatal density is physiologically more informative than stomatal index as SD is strongly related to maximum stomatal conductance. 

Korner C, Bannister P, Mark AF (1986) Altitudinal variation in stomatal conductance, nitrogen content and leaf anatomy in different plant life forms in New Zealand. Oecologia 69 577-588 Korner C, Cochrane PM (1985) Stomatal responses and water elations of Eucalyptus pauciflora in summer along an elevational gradient. Oecologia 66 443-455... 

Stomatal conductance numerical measure of the maximum rate of passage of either water vapor or carbon dioxide through the stomata (small pores on plant surfaces). 

SLN) Stomatal conductance Numerical measure of the rate of passage of 400-1400, varies0 Monti et al., 2005... 

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