Ionome of Soybean Seed Affected by Previous Cropping with Mycorrhizal Plant and Manure Application

Abstract

Two field experiments were conducted to investigate the effects of previous cultivation of an arbuscular mycorrhizal (AM) host plant and manure application on the concentration of 19 mineral elements in soybean ( Glycine max L. Merr. cv. Tsurumusume) seeds. Each experiment ran for two years (experiment 1 took place in 2007-2008, and experiment 2 took place in 2008-2009) with a split plot design. Soybeans were cultivated after growing either an AM host plant (maize, Zea mays L. cv. New dental) or a non-AM host plant (buckwheat, Fagopyrum esculentum Moench. cv. Kitawase-soba) in the first year in the main plots, with manure application (0 and 20 t/ha) during the soybean season in split plots from both main plots. On the basis of the two experiments, manure application significantly increased the available potassium (K) and decreased the available iron (Fe) and cesium (Cs) in the soil. However, higher concentrations of cadmium (Cd) and barium (Ba) and lower concentrations of Cs in the seed were induced by the application of manure. Cd levels in the seed were decreased by prior cultivation with the AM host plant. The present study showed that the identity of the prior crop and manure application changed the mineral contents of the soybean seed and suggests a connection between environmental factors and food safety.

The dynamic state of the ionome in roots, nodules, and shoots of soybean under different nitrogen status and at different growth stages

“…The increase in the low‐molecular‐weight organic acids released from manure and those secreted by the roots are hypothesized to have promoted the direct uptake and upward translocation of heavy metals because organic acids can increase the chelation and solubility of heavy metal ions ( Strickland et al, 2015). We previously reported that the M treatment increased the Cd and Ba concentrations of soybean seeds ( Sha et al, 2012). The increase in Ba and Sr concentrations of shoots were likely related to the Ca and Mg metabolism, because Mg, Ca, Sr and Ba are chemically similar and share translocation pathways ( Watmough , 2014).…”

“…The ionome is defined as all the mineral nutrients and trace elements found in an organism ( Salt et al, 2008). For crops, the ionome has predominantly been studied in soil, plant seeds or shoots to determine the nutritional status of plants ( Vohland et al, 2009; Sha et al, 2012; Chu et al, 2015; Pii et al., 2015). However, there is little information on the elemental composition of below‐ground parts, especially for legume crops with nodules.…”

Ionomic Analysis of Horticultural Plants Reveals Tissue-specific Element Accumulation

“…A positive correlation was also found between the chemically similar elements K and Na, but this correlation was not significant in previous studies (Baxter et al, 2012;Sha et al, 2012). Given that this correlation was previously analyzed on the basis of variation under different cultivation conditions, the absence of significance could have been due to a difference in the response to such cultivation conditions.…”

“…Ionomes of edible parts have been reported for rice and soybean (Norton et al, 2010;Sha et al, 2012). In soybean, dried mature seeds are used, and there are no reports of ionome analysis using immature soybean as a vegetable, edamame, as described in the present study.…”

“…Dried samples were digested with HNO 3 and subjected to an elemental analysis by inductively coupled plasma mass spectrometry (ELAN, DRC-e; PerkinElmer, Waltham, MA, USA), according to the method of Sha et al (2012). Five or more samples were collected from each individual and pooled for each individual for extraction.…”