Fast virtual histology using X-ray in-line phase tomography: application to the 3D anatomy of maize developing seeds

Abstract

BackgroundDespite increasing demand, imaging the internal structure of plant organs or tissues without the use of transgenic lines expressing fluorescent proteins remains a challenge. Techniques such as magnetic resonance imaging, optical projection tomography or X-ray absorption tomography have been used with various success, depending on the size and physical properties of the biological material.ResultsX-ray in-line phase tomography was applied for the imaging of internal structures of maize seeds at early stages of development, when the cells are metabolically fully active and water is the main cell content. This 3D imaging technique with histology-like spatial resolution is demonstrated to reveal the anatomy of seed compartments with unequalled contrast by comparison with X-ray absorption tomography. An associated image processing pipeline allowed to quantitatively segment in 3D the four compartments of the seed (embryo, endosperm, nucellus and pericarp) from 7 to 21 days after pollination.ConclusionThis work constitutes an innovative quantitative use of X-ray in-line phase tomography as a non-destructive fast method to perform virtual histology and extends the developmental stages accessible by this technique which had previously been applied in seed biology to more mature samples.Electronic supplementary materialThe online version of this article (doi:10.1186/s13007-015-0098-y) contains supplementary material, which is available to authorized users.

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

“…For instance, other sources and sensors of X-rays could be used to monitor seed imbibition such as the monochromatic synchrotron radiation sources or energy-resolved sensors, which give access to enhanced contrast. Such enhanced contrast has recently been shown for imbibed seeds during the morphogenesis of the seed [22], providing promising new insight into the imbibition process of seeds.…”

“…A limitation is that the contrast between imbibed tissue and dry tissue is almost null. In principle, the estimation of the imbibed part and the dry part could be better contrasted with the use of contrast agents, from solutions with metallic ions, such as those used in the biomedical domain for angiography [22,23]. While using such a solution, one should pay attention to its viscosity and its concentration.…”

Transcriptomics at maize embryo/endosperm interfaces identify a novel transcriptionally distinct endosperm sub-domain adjacent to the embryo scutellum (EAS)

“…A188 and B73 inbred lines were cultivated in the green house as described previously (Rousseau et al, 2015). The emb8522 mutant in the rcsm-2 background and the B73 plants used for in situ hybridization were grown in a field plot located at the ENS de Lyon, France.…”

“…Shoot and root meristems will respectively surrounded by the protective coleoptile and coleorhiza (Bommert and Werr, 2001;Randolph, 1936;Vernoud et al, 2005). The surrounding endosperm, which occupies 70% of the kernel volume at the end of the early development (Leroux et al, 2014;Rousseau et al, 2015;Sabelli and Larkins, 2009;Zhan et al, 2017), has been described as differentiating only four main cell types. The basal endosperm transfer layer (BETL) and the aleurone layer (AL) are two peripheral cell types in contact with maternal tissues.…”

X-ray phase contrast imaging ofVitisspp. buds shows freezing pattern and correlation between volume and cold hardiness

“…Tomography imaging is an underused technique in plant sciences (Staedler et al , 2013) that may be an alternative for the study of morphological differences between buds. This technique has recently become a consolidated method for the study of xylem and wood characteristics (Mayo et al , 2010; Sedighi Gilani et al , 2014; Cochard et al , 2015; Torres-Ruiz et al , 2015; Choat et al , 2016; Malek et al , 2016; Nardini et al , 2017; Scoffoni et al , 2017; Koddenberg and Militz, 2018), but other plant structures have also been imaged, such as developing maize seeds (Rousseau et al , 2015), tomato leaves (Verboven et al , 2015), and flowers and floral buds (Staedler et al , 2013; Tracy et al , 2017).…”