Stomatal design principles in synthetic and real leaves

Figure 1. Gas exchange for photosynthesis and respiration takes place by way of small stoma pores on the surface of plant leaves. (a,b) Stoma apertures are approximately circular with radius a, and a boundary layer of thickness h separates the pores from the bulk atmosphere. The pore-to-pore distance is d ¼ r21/2, where r is the stomatal density. (c) The action of guard cells allows for opening and closing of the pore in response to environmental cues. When fully open pores are often circular in shape with radius approximately one-sixth of the total stoma complex length. Panels (d–h) illustrate the diversity of stoma size and density. (d) Swillingtonia denticulata (image modified from [1]), (e) Aglaophyton major (image modified from [2]) ( f ) Citrus reticulata, (g) Gossypium hirsutum and (h) Nephrolepis exaltata.

by Zwieniecki M., Haaning K. S., Boyce C. K., Jensen K. H. (2016)

Maciej A. Zwieniecki 1 , Katrine S. Haaning 2 , C. Kevin Boyce 3 , Kaare H. Jensen 2

1 Department of Plant Sciences, University of California, Davis, CA 95616, USA

2 Department of Physics, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark

3 Department of Geological Sciences, Stanford University, Stanford, CA 94305, USA

 

in J. R. Soc. Interface 13: 20160535. – http://dx.doi.org/10.1098/rsif.2016.0535

http://jensen-research.com/wp-content/uploads/2014/09/24_Jensen_JRSI2016.pdf

Stomata are portals in plant leaves that control gas exchange for photosynthesis, a process fundamental to life on Earth. Gas fluxes and plant productivity depend on external factors such as light, water and CO2 availability and on the geometrical properties of the stoma pores.

The link between stoma geometry and environmental factors has informed a wide range of scientific fields—from agriculture to climate science, where observed variations in stoma size and density are used to infer prehistoric atmospheric CO2 content.

However, the physical mechanisms and design principles responsible for major trends in stomatal patterning are not well understood. Here, we use a combination of biomimetic experiments and theory to rationalize the observed changes in stoma geometry.

We show that the observed correlations between stoma size and density are consistent with the hypothesis that plants favour efficient use of space and maximum control of dynamic gas conductivity, and that the capacity for gas exchange in plants has remained constant over at least the last 325 Myr.

Our analysis provides a new measure to gauge the relative performance of species based on their stomatal characteristics.