First Form, Then Function: 3D Reconstruction of Cucumber Plants (Cucumis sativus L.) Allows Early Detection of Stress Effects through Leaf Dimensions

Dany Moualeu-Ngangué,Maria Bötzl,Hartmut Stützel

doi:10.3390/rs14051094

Abstract

Detection of morphological stress symptoms through 3D examination of plants might be a cost-efficient way to avoid yield losses and ensure product quality in agricultural and horticultural production. Although the 3D reconstruction of plants was intensively performed, the relationships between morphological and physiological plant responses to salinity stress need to be established. Therefore, cucumber plants were grown in a greenhouse in nutrient solutions under three salinity treatments: 0, 25, and 50 mM NaCl. To detect stress-induced changes in leaf transversal and longitudinal angles and dimensions, photographs were taken from plants for 3D reconstruction through photogrammetry. For assessment of physiological stress responses, invasive leaf measurements, including the determination of leaf osmotic potential, leaf relative water content, and the leaf dry to fresh weight ratio, were performed. The transversal and longitudinal leaf dimensions revealed statistically significant differences between stressed and control plants after 60 °Cd (day 3) for the leaves which appeared before stress imposition. Strong correlations were found between the transversal width and some investigated physiological traits. Morphological changes were shown as indicators of physiological responses of leaves under salinity stress.

Highlights

Academic Editors: Laura HarrisonPlants are constantly subjected to changes in environmental variables, which might act as stressors when a certain threshold is reached
Significant yield loss and reduction in photosynthetic traits were observed in plants under salinity stress [3,4,5]
Some morphological traits such the transversal correlations were found between the as transversal widths and and longitudinal traits, such as the dry and length of the leaf appeared to the be better indicators of salinity stress than thethe physiological fresh weight of leaf disk harvested destructively during experiments (Figure 6c,d)

Summary

Introduction

Academic Editors: Laura HarrisonPlants are constantly subjected to changes in environmental variables, which might act as stressors when a certain threshold is reached. If the plant cell cannot distribute sodium efficiently, the plant is forced to exclude sodium from the leaf, which is energy costly. If this adaptation mechanism collapses, the plant suffers from sodium toxicity [2,3]. As part of the stress avoidance strategy, a change of leaf angle might help to prevent water loss through transpiration, alongside the reduction in the stomatal conductance, leaf rolling, and the reduction in leaf area growth [3]. Significant yield loss and reduction in photosynthetic traits were observed in plants under salinity stress [3,4,5]. Early stress detection might help to prevent yield reduction

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