The bias of a two‐dimensional view: comparing two‐dimensional and three‐dimensional mesophyll surface area estimates using noninvasive imaging

Journal Article · Mon Jul 10 00:00:00 EDT 2017 · New Phytologist

DOI:https://doi.org/10.1111/nph.14687· OSTI ID:1373818

Théroux‐Rancourt, Guillaume  ^[1]; Earles, J. Mason ^[2]; Gilbert, Matthew E. ^[1]; Zwieniecki, Maciej A. ^[1]; Boyce, C. Kevin ^[3]; McElrone, Andrew J. ^[4]; Brodersen, Craig R. ^[2]

---

1. Department of Plant Sciences University of California Davis Davis CA 95616 USA
2. School of Forestry &, Environmental Studies Yale University New Haven CT 06511 USA
3. Department of Geological Sciences Stanford University Stanford CA 94305 USA
4. USDA‐Agricultural Research Service Davis CA 95616 USA, Deparment of Viticulture and Enology University of California Davis CA 95616 USA

Summary The mesophyll surface area exposed to intercellular air space per leaf area ( S _m ) is closely associated with CO ₂ diffusion and photosynthetic rates. S _m is typically estimated from two‐dimensional (2D) leaf sections and corrected for the three‐dimensional (3D) geometry of mesophyll cells, leading to potential differences between the estimated and actual cell surface area. Here, we examined how 2D methods used for estimating S _m compare with 3D values obtained from high‐resolution X‐ray microcomputed tomography (microCT) for 23 plant species, with broad phylogenetic and anatomical coverage. Relative to 3D, uncorrected 2D S _m estimates were, on average, 15–30% lower. Two of the four 2D S _m methods typically fell within 10% of 3D values. For most species, only a few 2D slices were needed to accurately estimate S _m within 10% of the whole leaf sample median. However, leaves with reticulate vein networks required more sections because of a more heterogeneous vein coverage across slices. These results provide the first comparison of the accuracy of 2D methods in estimating the complex 3D geometry of internal leaf surfaces. Because microCT is not readily available, we provide guidance for using standard light microscopy techniques, as well as recommending standardization of reporting S _m values.

• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: DE‐AC02‐05CH11231; AC02-05CH11231
• OSTI ID: 1373818
• Journal Information: New Phytologist, Journal Name: New Phytologist Vol. 215 Journal Issue: 4; ISSN 0028-646X
• Publisher: Wiley-Blackwell
• Country of Publication: United Kingdom
• Language: English