Multiscale quantification of morphodynamics: MorphoLeaf, software for 2-D shape analysis

Abstract

A major challenge in morphometrics is to analyse complex biological shapes formed by structures at different scales. Leaves exemplify this challenge as they combine differences in their overall shape with smaller shape variations at their margin leading to lobes or teeth. Current methods based on contour or on landmarks analysis are successful in quantifying either overall leaf shape or leaf margin dissection, but fail in combining the two. Here, we present a comprehensive strategy and its associated freely available platform for the quantitative, multiscale analysis of the morphology of leaves with different architectures. For this, biologically relevant landmarks are automatically extracted and hierarchized, and used to guide the reconstruction of accurate average contours that properly represent both global and local features. Using this method we established a quantitative framework of the developmental trajectory of Arabidopsis leaves of different ranks and retraced the origin of leaf heteroblasty. When applied to different mutant forms our method can contribute to a better comprehension of gene function as we show here for the role of CUC2 during Arabidopsis leaf serration. Finally, we illustrated the wider applicability of our tool by analysing hand morphometrics.

PaCeQuant: A Tool for High-Throughput Quantification of Pavement Cell Shape Characteristics

“…For example, shapes were quantified by use of Fourier-based descriptors (McLellan and Endler, 1998), moments, geometric codes, and margin statistics (Kalyoncu and Toygar, 2015), and leaf serration was quantified using hierarchy analyses (Biot et al, 2016). With improving imaging techniques, several studies addressed the dynamics and changes of PC shape during leaf development and expansion (Iwata and Ukai, 2002;Andriankaja et al, 2012;Elsner et al, 2012;Barbier de Reuille et al, 2015;Vanhaeren et al, 2015).…”

Morphometric and colourimetric tools to dissect morphological diversity: an application in sweet potato [Ipomoea batatas (L.) Lam.]

“…Morphometric parameters were previously reported as useful tools to capture leaf shape information and their accuracy to improve morphological characterizations and contribute effectively with accurate data in genetic studies (Chitwood et al ). This method based on contour and on landmark analyses previously demonstrated its success quantifying leaf shape and leaf margin, and contributed to a better understanding of gene functions (Biot et al 2016) and natural diversity determinations (Nicotra et al 2011). Combined analyses showed the power of including quantitative data in morphological characterizations to efficiently discriminate sweet potato accessions.…”

Getting leaves into shape: a molecular, cellular, environmental and evolutionary view

“…In Arabidopsis, for example, juvenile leaves are round and have a rather smooth leaf margin whereas adult leaves show a more elliptical shape with small serrations. Such morphological differences result from early divergence of the developmental trajectories of leaf primordia of different nodes (Biot et al, 2016). In recent years, a number of factors that control this divergence have been identified.…”