Two Inexpensive and Non-destructive Techniques to Correct for Smaller-Than-Gasket Leaf Area in Gas Exchange Measurements.

Abstract

The development of technology, like the widely-used off-the-shelf portable photosynthesis systems, for the quantification of leaf gas exchange rates and chlorophyll fluorescence offered photosynthesis research a massive boost. Gas exchange parameters in such photosynthesis systems are calculated as gas exchange rates per unit leaf area. In small chambers ( 2 ), the leaf area used by the system for these calculations is actually the internal gasket area (A G ), provided that the leaf covers the entire A G . In this study, we present two inexpensive and non-destructive techniques that can be used to easily quantify the enclosed leaf area (A L ) of plant species with leaves of surface area much smaller than the A G , such as that of cereal crops. The A L of the cereal crop species studied has been measured using a standard image-based approach ( i A L ) and estimated using a leaf width-based approach ( w A L ). i A L and w A L did not show any significant differences between them in maize, barley, hard and soft wheat. Similar results were obtained when the w A L was tested in comparison with i A L in different positions along the leaf in all species studied. The quantification of A L and the subsequent correction of leaf gas exchange parameters for A L provided a precise quantification of net photosynthesis and stomatal conductance especially with decreasing A L . This study provides two practical, inexpensive and non-destructive solutions to researchers dealing with photosynthesis measurements on small-leaf plant species. The image-based technique can be widely used for quantifying A L in many plant species despite their leaf shape. The leaf width-based technique can be securely used for quantifying A L in cereal crop species such as maize, wheat and barley along the leaf. Both techniques can be used for a wide range of gasket shapes and sizes with minor technique-specific adjustments.

Plant phenotyping relevance

小葉の葉面積を画像法・葉幅法で非破壊推定し、ガス交換測定を補正する手法の開発・比較検証が研究の中心である。

Code and data availability

The paper describes image-based and leaf-width-based leaf area quantification for gas exchange measurements, but contains no public phenotype dataset deposit, no author analysis code/scripts, no trained models, and no explicit data availability statement. The supplementary material link is generic and not described as含

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