Analysis of the peel structure of different Citrus spp. via light microscopy, SEM and μCT with manual and automatic segmentation.

Abstract

The peels of lime, lemon, pomelo and citron are investigated at macroscopic and microscopic level. The structural composition of the peels is compared and properties such as peel thickness, proportion of flavedo, density and proportion of intercellular spaces are determined. μCT images are used to visualize vascular bundles and oil glands. SEM images provide information about the appearance of the cellular tissue in the outer flavedo and inner albedo. The proportion of intercellular spaces is quantitatively determined by manual and software-assisted analysis (ilastik). While there are macroscopic differences in the fruits, they differ only slightly in the orientation of the vascular bundles and the arrangement of the oil glands. However, in peel thickness and flavedo thickness, the fruit peels differ significantly from each other. There are no significant differences between the two analysis methods used, although the use of ilastik is preferred due to time reduction of up to 70%. The large amount of intercellular spaces in the albedo but also the denser flavedo both have a mechanical protective function to prevent damage to the fruit. In addition, the entire peel structure is mechanically reinforced by vascular bundles. This combination of penetration protection (flavedo) and energy dissipation (albedo) makes Citrus spp. peels a promising inspiration for technical material systems.

Plant phenotyping relevance

柑橘果皮の構造形質を光学・SEM・μCT画像から取得し、手動法とソフトウェア支援セグメンテーションを比較・検証しているため、植物形質取得法が中心である。

Code and data availability

The paper's phenotype data (thin-section images, µCT/SEM scans, segmentation datasets) are not publicly deposited; the Data Availability Statement says the data is available upon reasonable request, so authors must be contacted. No public URL or repository is provided.

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