Tree crowns grow into self-similar shapes controlled by gravity and light sensing

Duchemin, Laurent; Eloy, Christophe; Badel, Éric; Moulia, Bruno

doi:10.1098/rsif.2017.0976

Cited by 20 publications

(25 citation statements)

References 41 publications

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“…They can actively trigger growth-driven motions-called tropisms-to adapt their posture, following given external cues. Gravity and light are two obvious external cues, regularly put forward to explain plant shaping (7). However Bastien et al (8,9) have highlighted the importance of proprioception and autotropism in posture regulation processes.…”

Section: Introductionmentioning

confidence: 99%

The hook shape of growing leaves results from an active regulatory process

Rivière

Peaucelle

et al. 2020

Journal of Experimental Botany

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The rachis of most growing compound leaves observed in nature exhibit a stereotyped hook shape. In this study, we focus on the canonical case of Averrhoa carambola. Combining kinematics and mechanical investigation, we characterize this hook shape and shed light on its establishment and maintenance. We show quantitatively that the hook shape is a conserved bent zone propagating at constant velocity and constant distance from the apex throughout development. A simple mechanical test reveals non-zero intrinsic curvature profiles for the rachis during its growth, indicating that the hook shape is actively regulated. We show a robust spatial organization of growth, curvature, rigidity and lignification and their interplay. Regulatory processes appear to be specifically localized: in particular, differential growth occurs where the elongation rate drops. Finally, impairing the graviception of the leaf on a clinostat led to reduced hook curvature but not to its loss. Altogether our results suggest a role for proprioception in the regulation of the leaf hook shape, likely mediated via mechanical strain.

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Section: Introductionmentioning

confidence: 99%

The hook shape of growing leaves results from an active regulatory process

Rivière

Peaucelle

et al. 2020

Journal of Experimental Botany

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“…Different tree phenotypes produce different degrees of occlusion under various scanning views. For example, the maximal zenith angle of the sun near the equator places the sun more directly above plants, and for tall trees with flat crowns, more leaves are exposed when the sun is in this position (Duchemin et al, 2018). Hence, aerial scanning patterns above the tree crown can capture more leaf elements than TLS patterns.…”

Section: Suggested Scanning Methods To Alleviate Occlusionmentioning

confidence: 99%

Simulation of multi-platform LiDAR for assessing total leaf area in tree crowns

Yun

Cao

et al. 2019

Agricultural and Forest Meteorology

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LiDAR (Light Detection and Ranging) technology has been increasingly implemented to assess the biophysical attributes of forest canopies. However, LiDAR-based estimation of tree biophysical attributes remains difficult mainly due to the occlusion of vegetative elements in multi-layered tree crowns. In this study, we developed a new algorithm along with a multiplescan methodology to analyse the impact of occlusion on LiDAR-based estimates of tree leaf area.We reconstructed five virtual tree models using a computer graphic-based approach based on in situ measurements from multiple tree crowns, for which the position, size, orientation and area of all leaves were measured. Multi-platform LiDAR simulations were performed on these 3D tree models through a point-line intersection algorithm. An approach based on the Delaunay triangulation algorithm with automatic adaptive threshold selection was proposed to construct the scanned leaf surface from the simulated discrete LiDAR point clouds. In addition, the leaf area covered by laser beams in each layer was assessed in combination with the ratio and number of the scanned points. Quantitative comparisons of LiDAR scanning for the occlusion effects among various scanning approaches, including fixed-position scanning, multiple terrestrial LiDAR scanning and airborne-terrestrial LiDAR cross-scanning, were assessed on different target trees. The results showed that one simulated terrestrial LiDAR scan alongside the model tree captured only 25-38% of the leaf area of the tree crown. When scanned data were acquired from three simulated terrestrial LiDAR scans around one tree, the accuracy of the leaf area recovery rate reached 60-73% depending on the leaf area index, tree crown volume and leaf area density. When a supplementary airborne LiDAR scanning was included, occlusion was reduced and the leaf area recovery rate increased to 72-90%. Our study provides an approach for the measurement of total leaf area in tree crowns from simulated multi-platform LiDAR data and enables a quantitative assessment of occlusion metrics for various tree crown attributes under different scanning strategies.

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“…In real life situations the interception of light by leaves is complex as the rays are not simply in the direction of the Sun: light diffusion through the atmosphere called sky radiation and light scattering by clouds or other leaves are all non-negligible sources of radiation [27][28][29]. The direction of light is particularly important as models to explain the shape of real life trees based on that aspect has been proposed in the past [17,19]. Despite the complexity of the issue, the present model will only account for direct sunlight and ignore diffusion and scattering.…”

Section: Light Interception Factor For Productivitymentioning

confidence: 99%

“…Such model is supposed to be analogous to phloem transport, the phloem being the part of the tree that handles the transport of the sugar photosynthesized at the leaves [15,16]. Though the relation between the models introduced in the present paper and real plants should not be taken beyond an analogy, it can be noted that the literature on plants has a wealth of quite simplistic theoretical or numerical models to explain specific aspects of plants [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Growth of a tree with allocations rules: part 2 dynamics

Bui

Leoncini

2021

Eur. Phys. J. B

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Following up on a previous work [1] we examine a model of transportation network in some source-sink flow paradigm subjected to growth and resource allocation. The model is inspired from plants, and we add rules and factors that are analogous to what plants are subjected to. We study how different resource allocation schemes affect the tree and how the schemes interact with additional factors such as embedding the network into a 3D space and applying gravity or shading. The different outcomes are discussed.

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Tree crowns grow into self-similar shapes controlled by gravity and light sensing

Cited by 20 publications

References 41 publications

The hook shape of growing leaves results from an active regulatory process

The hook shape of growing leaves results from an active regulatory process

Simulation of multi-platform LiDAR for assessing total leaf area in tree crowns

Growth of a tree with allocations rules: part 2 dynamics

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