Establishment of a Cultivation Mode of Glycine soja, the Bridge of Phytoremediation and Industrial Utilization

Abstract

Soil salinity is a growing challenge for today’s agriculture. It is one of the most brutal abiotic factors limiting crop productivity globally. Millions of hectares of agricultural land throughout the world are too saline to produce economic crop yields and the area affected by salt accumulation is increasing day by day. Saline soils could however be a potential land resource with utilization value under the process of phytoremediation. Wild soybean (Glycine soja) is a salt-tolerant plant widely used in the cosmetic and pharmaceuticals industries as well as in crop improvement programs. This crop shows potential value for saline soil phytoremediation. However, due to its procumbent growth habit, accumulation of biomass is reduced and consequently reducing its value in phytoremediation. In this study, artificial facilities were used to make wild soybeans grow upright. Compared to the control plants, which yielded 1629.74 kg/ha of seed and 6075.76 kg/ha above ground biomass, erect wild soybean plants yielded 2608.10 kg/ha of seed and 10,286.40 kg/ha of above ground biomass (dry weight). The potential phytoremediation ability of wild soybean was also studied. The wild soybean could absorb up to 264.57 kg soluble salt/ha/year with an average of 25.72‰ salt content. The soluble salt content in the wild soybean rhizosphere was 1.50‰ higher than that in the bulk soil, suggesting that the rhizosphere of wild soybean can enrich soluble salt. The K–Na ratio of seed, leaf, shoot, and capsule were all greater than 1 suggesting that the wild soybean has a good salt tolerance capacity. Additionally, the bioaccumulation factor (BF) value of Na in roots was >1 suggesting that the root of wild soybean was the main organ for Na+ storage and suitable for Na phytostabilization. Furthermore, wild soybean could be potentially play an important role in Ca and Mg phytostabilization due to their corresponding BF values, which were greater than 1 in different organs. In other words, the establishment of a cultivation mode of wild soybean, as demonstrated in this study, will be a bridge towards phytoremediation of saline soils and better industrial utilization of the crop.