Evaluation of 3D/2D Imaging and Image Processing Techniques for the Monitoring of Seed Imbibition

Abstract

Seed imbibition is a very important process in plant biology by which, thanks to a simple water income, a dry seed may turn into a developing organism. In natural conditions, this process occurs in the soil, e.g., with difficult access for a direct observation. Monitoring the seed imbibition with non-invasive imaging techniques is therefore an important and possibly challenging task if one tries to perform it in natural conditions. In this report, we describe a set of four different imaging techniques that enable to addressing this task either in 3D or in 2D. For each technique, the following items are proposed. A detailed experimental protocol is provided to acquire images of the imbibition process. With the illustration of real data, the significance of the physical quantities measured in terms of their relation to the income of water in the seed is presented. Complete image analysis pipelines are then proposed to extract dynamic information on the imbibition process from such monitoring experiments. A final discussion compares the advantages and current limitations of each technique in addition to elements concerning the associated throughput and cost. These are criteria especially relevant in the field of plant phenotyping where large populations of plants are imaged to produce quantitatively significative traits after image processing.

First the seed: Genomic advances in seed science for improved crop productivity and food security

“…Function References 3D and 2D Imaging platforms Noninvasive universally applicable to any seed providing significant contrast capable of qualitatively characterizing the seed imbibition 3D X-ray: high spatial resolution; no difference in contrast between dry and imbibed tissue; contrast agent viscosity and its concentration matters 3DMRI: characterize water dynamics in space and time; coarse spatial resolution; greater signal-to-noise ratio in finer resolution; low throughput 2D thermography: Detect and characterize imbibition associated with biophysical and biochemical changes; sensor sensitive to radiations 2D bio-speckle: Low-cost high throughput, measures micromovements at the surface of samples linked to water fluxes; sensitive to fluctuation in mechanical vibrations and sample size to be imaged Belin et al, 2018 Machine vision platform An electronic force transducer to measure imbibition of individual seeds with high resolution but low throughput; uses change in area (∆A) as a function of time and swelling coefficient (k) to measure seed imbibition Uses near-infrared spectrum and seed weight to estimate seed ACP that correlate highly with plant dry weight and 100-seed weight; suitable for rapid assessment of seed vigor in crops…”

Emerging thermal imaging techniques for seed quality evaluation: Principles and applications

“…Therefore, thermal imaging technique has been proposed as a good alternative instead of the conventional methods of seed viability evaluation. The resulting thermal images provide thermal profiles of the seeds with demonstrated changes in temperature distribution that are strongly correlated with seed viability (Belin et al, 2018;Kranner et al, 2010), and this enables the distinguish of viable seeds from the nonviable ones (Zhang et al, 2018).…”

“…Depending on the type of sensors, acquisition mode and the mathematical chemometrics models used in the analysis, spectral techniques relies on the analysis of light after being reflected, absorbed or transmitted from the examined seeds. Imaging techniques such as spectral imaging, X-ray imaging, thermal imaging, fluorescence imaging, and magnetic resonance imaging provide great capabilities of demonstrating the essential quality attributes (Belin et al, 2018). For instance, X-ray imaging and magnetic resonance imaging techniques are used when the internal anatomical details of the examined seeds are required to estimate seed maturity, internal structure, germination capacity, dormancy, viability, vigor, insect infestation and internal damages in embryo and endosperm (Dell'Aquila, 2004).…”

“…For instance, X-ray imaging and magnetic resonance imaging techniques are used when the internal anatomical details of the examined seeds are required to estimate seed maturity, internal structure, germination capacity, dormancy, viability, vigor, insect infestation and internal damages in embryo and endosperm (Dell'Aquila, 2004). Meanwhile, spectral imaging and fluorescence imaging techniques are used to know information about the major composition of the seeds (Belin et al, 2018). In seed industry, establishment of imaging techniques can solve many ill-posed issues related to quality assessment and authentication tasks.…”

Recent Applications of Multispectral Imaging in Seed Phenotyping and Quality Monitoring—An Overview

“…Therefore, the potential of using non-destructive methods such as imaging techniques, NIR spectroscopy or precise remote sensors to overcome the limitations of conventional methods is gaining increasing attention [ 18 ]. The imaging techniques such as spectral imaging, thermal imaging, fluorescence imaging X-ray imaging, and magnetic resonance imaging offer reliable alternatives to the traditional destructive methods [ 20 , 21 ]. The X-ray imaging and magnetic resonance imaging are able to provide anatomical details and the spectral imaging, thermal imaging and fluorescence imaging are usually utilized to deliver the functional and nutritional information about the seeds being examined [ 21 ].…”