Silicophytoliths from soybean plants in different growth stages of the Argentine Pampas

For decades, silicophytolith and silicon (Si) studies have been conducted on plant families which produce high amounts of this compound, such as horsetails, grasses, sedges, and palms. However, in recent years, studies on low silicophytolith-producing families became relevant because of the important role this compound plays in their growth. In cultivated soils from South America, research on silicophytolith production in crops and on the availability of silicon sinks is scarce. The present study is the first report of silicophytolith production in soybean plants, using staining and calcination techniques. The silicophytolith morphologies found in leaves were tabular lobate, hair bases, long and short hairs, stomatal complexes, cylindrical sulcate tracheid, elongate with fusiform edges, articulated, and orbicular cells with thickened edges silicified; in stems, branches, pods, and flowers, the silicophytoliths were orbicular and cylindrical sulcate tracheid. Throughout their growth, these soybean crops produced 1.04, 25.12, and 40.08 kg ha-1 of silicophytoliths in vegetative (S12), reproductive (S61), and maturity stages (S89), respectively. These results will contribute to the knowledge of the amount of silica/silicophytoliths involved in the process of Si-recycling through cultivated vegetation in fields from humid plains in medium latitude.