Abstract Detail

Anatomy and Morphology

Borsuk, Aleca [1], Roddy, Adam [2], Theroux-Rancourt, Guillaume [3], Brodersen, Craig [4].

Structural organization of the spongy mesophyll in laminar leaves with reticulate venation.

Plant leaves are typically composed of two layers of photosynthetic tissue, the palisade and spongy mesophyll. While the palisade mesophyll is formed by tightly packed columnar cells, the structure of the spongy mesophyll is less understood and often treated as irregular or random. Here, we characterized the two-dimensional (2D) and three-dimensional (3D) structure of the spongy mesophyll in laminar leaves with reticulate venation in 40 species representing 30 genera. The spongy mesophyll of all species was a bicontinous structure of living tissue supporting interconnected networks of air space. The spongy mesophyll layer in most species was composed of cells with lobes coplanar to the epidermis giving rise to an emergent, ordered structure with the topological properties of a honeycomb. This honeycomb-like topology, observed among disparate groups such as ferns, gymnosperms, and angiosperms, was governed by a simple set of allometric scaling laws. A subset of species with small cells, high cell packing densities, and close vein spacing had an irregular morphology that was associated with high surface-area-to-volume ratios and maximum photosynthetic rates. Our study calls for a revised understanding of leaf construction that opens the door to more spatially sophisticated explorations of leaf development, economics, physiology, and biomechanics.

1 - Yale School of the Environment, 370 Prospect Street, Greeley Memorial Laboratory, New Haven, Connecticut, 06511, United States
2 - Yale University, Forestry & Environmental Studies, 370 Prospect St, New Haven, CT, 06511, United States
3 - University of Natural Resources and Life Sciences (BOKU Wien), Institute of Botany, Austria
4 - Yale University, School Of Forestry & Environmental Studies, 195 Prospect Street, Kroon Hall, New Haven, CT, 06511, United States

Keywords:
mesophyll
microCT
photosynthesis.

Presentation Type: Oral Paper
Session: AM1, Anatomy and Morphology
Location: Virtual/Virtual
Date: Wednesday, July 29th, 2020
Time: 1:00 PM
Number: AM1012
Abstract ID:312
Candidate for Awards:Katherine Esau Award,Maynard F. Moseley Award