Calcium oxalate crystal production and density at different phenological stages of soybean plants (Glycine max L.) from the southeast of the Pampean Plain, Argentina

Abstract

Glycine max L. (soybean) is one of the major crops of the world. Although the process of biomineralisation has been reported in some organs of soybean, we now report the description and quantification of calcium oxalate crystals in vegetative and reproductive organs of soybean during its life cycle, as they act as an important source of calcium to the soil, once the harvesting is finished. Through diaphanisation, cross-sectioning, optical and scanning electron microscopy analysis of the organs, morphology, size and location of the crystals were identified. In addition, crystal density (n° crystals·mm ) and the input of crystals to soil (n° crystals·ha ) were calculated. Soybean produced prismatic calcium oxalate crystals in vegetative and reproductive organs, generally associated with vascular bundles, resulting in a potencial transfer to the soil of 81.4 x 10 crystals·ha throughout its life cycle. Pods were the organs with higher calcium oxalate crystal production (1112.7 ± 384.6 crystals·mm ), but with the smaller size (12.3 ± 2.1 μm long). However, cotyledons were the organs that produce the larger crystals (21.3 ± 3.5 μm long), but in lesser amounts (150.9 ± 64.4 crystals·mm ). In leaves, although crystal size did not differ from vegetative to reproductive stage (14.5 ± 4.2 and 14.5 ± 4 μm in length, respectively), the crystal density increased (293.2 and 409 crystals·mm , respectively). These results will contribute to knowledge of the amount of calcium oxalate crystals involved in the process of Ca recycling through cultivated vegetation in fields from humid plains at medium latitudes, which therefore have biological, botanical, biogeochemical and pedological relevance.

Are calcium oxalate crystals a dynamic calcium store in plants?

“…Excess calcium as CaOx crystals eliminated in this manner is recycled when discarded organs decompose, thus returning a noticeable amount of calcium from CaOx crystals to the soil (Smith et al ., ; Dauer & Perakis, ; Borrelli et al ., ; Uren, ). However, some species of Cactaceae, which are devoid of leaves and incapable of discarding nonfunctional phloem, accumulate CaOx crystals, which can reach up to 80% of their dry weight (see Franceschi & Nakata, ), reinforcing this hypothesis of excess calcium excretion as the function of CaOx crystals.…”

Calcium Oxalate Crystals in Plant Communities of the Southeast of the Pampean Plain, Argentina

“…32.2a-e), whereas in some aquatic species (T. latifolia, R. crispus) COC were also distributed in the cells around the air spaces of aerenchyma tissue (Fig. 32.2k) (Graciotto Silva-Brambilla and Moscheta 2001;Jáuregui-Zúñiga et al 2003;Cervantes-Martínez et al 2005;Torres Boeger et al 2007;Borrelli et al 2009Borrelli et al , 2011Borrelli et al , 2016. These COC distribution patterns could be related with their a-e, g, i), 100 μm (f, h, j-k) different functions.…”

“…Terrestrial species produced druses (E. globulus, C. ehrenbergiana, H. bonariensis) and prisms (E. globulus, A. melanoxylon, G. max) (Fig. 32.2a-e, Table 32.1) (O'Connell et al 1983;Ilarslan et al 1997;Borrelli et al 2009Borrelli et al , 2016He et al 2012He et al , 2013, while aquatic plants produced druses (R. crispus, P. hydropiperoides, L. peploides, A. philoxeroides) and raphides (T. latifolia, L. peploides) (Fig. 32.2f-l, Table 32.1) (Kausch and Horner 1983;Kuo-Huang et al 1994;Prychid and Rudall 1999;Graciotto Silva-Brambilla and Moscheta 2001;Lytle 2003;Duarte and Debur 2004;Borrelli et al 2011).…”

Oxalate Carbonate Pathway—Conversion and Fixation of Soil Carbon—A Potential Scenario for Sustainability

“…Recent studies show many plants species (oxalogenic plants) contain oxalates (of calcium) as part of their metabolism and accumulate in various parts (commonly in roots, leaves, and barks) depending on the type of plant (Figure 1). Oxalogenic plants are imperative for the induction, maintenance, and strengthening of inorganic carbon assimilation (Borrelli et al, 2016;Pierantoni et al, 2018). Furthermore, the termites, saprophytic fungi, and rhizosphere microbial community carry out the degradation of oxalogenic biomass releasing and maintaining the oxalate pool (Cailleau et al, 2011).…”