Morphological analysis of the seeds of three pseudocereals by using light microscopy and ESEM-EDS

Abstract

The seed morphology of three Pseudocereal Grains (PSCg), i.e. quinoa (Chenopodium quinoa Willd, Chenopodiaceae), buckwheat (Fagopyrum esculentum Moench, Polygonaceae) and amaranth (Amaranthus caudatus L., Amaranthaceae) was studied by light microscopy (LM) and Environmental Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (ESEM-EDS). LM was used with visible light to evaluate either unstained sections or sections stained with Azan mixture and with fluorescent light. The aim of the study was to compare the architecture of the three seeds in order to connect their morphology with nutrient localization. The Azan staining allowed for the visualization of the seed coat, the embryo - with its shoot apical meristem - and the radicle cell layers, whereas the use of fluorescent microscopy identified the cells rich in phenolic compounds. Finally, the ESEM-EDS analysis revealed that the seed coat of the quinoa was thinner than that of amaranth or buckwheat. In all PSCg, starch granules appeared to be located in large polygonal cells, surrounded by a thin cell wall. Several globoids of proteins were observed in the embryo cells. In the radicle section, the vascular bundles of the procambium were evident, while Amaranth only showed a consistent layer of calcium crystals, located between the embryo and the perysperm. The morphological differences of the three PSCg were discussed in the context of their structural resistance to processing technologies which impact on nutritional value of derived foods.

A morphological analysis of fresh and brine-cured olives attacked by <em>Bactrocera oleae</em> using light microscopy and ESEM-EDS

“… 27 In this kind of approach, microscopy and molecular biology investigations may be complementary tools. 30 The EDS elemental composition of the brine-cured TOs, combined with the fluorescence analysis of the phenolic pool, allows us to control TO salt treatments and washing times in order to adapt the transformation processes to each specific olive cultivar. Hence, we can minimize losses of seco-BPs in the processing and avoid the use of excessive quantities of salt.…”

Exploration on bioactive properties of quinoa protein hydrolysate and peptides: a review

“…The major anatomical parts of quinoa seeds include a large central perisperm and a peripheral embryo (consisted of a hypocotyl-radicle axis and two cotyledons) (Burrieza, López-Fernández, and Maldonado 2014). The cells of the perisperm are full of starch granules, while protein is located mostly in the embryo (Prego, Maldonado, and Otegui 1998;Ninfali et al 2020). D' Amico et al (2019 performed a study in which the quinoa seeds were milled by a laboratory scale abrasive mill for 8 min by intervals of 1 min.…”

Comparative Analysis Reveals Changes in Some Seed Properties in Amaranth Mutant Variety ‘Zobor’ (A. hypochondriacus × A. hybridus)

“…The amaranth seed size, as one of the morphometric parameters, is generally not the topic of interest [28], although seed morphology has been described in detail by several authors [29][30][31]. Pseudocereal grains show different external and internal seed architecture with consequent differences in nutrient distribution [30].…”

“…The amaranth seed size, as one of the morphometric parameters, is generally not the topic of interest [28], although seed morphology has been described in detail by several authors [29][30][31]. Pseudocereal grains show different external and internal seed architecture with consequent differences in nutrient distribution [30]. This characterization can, therefore, reveal different and specific microvariations (in seed architecture, shape, color, and weight) within the Amaranthus genus and may be helpful for breeders to select suitable cultivars.…”