Low concentration of corn steep liquor promotes seed germination, plant growth, biomass production and flowering in soybean

Abstract

Corn steep liquor (CSL), which has a great potential use in agricultural production, is an organic liquid waste discharged from corn wet-milling. In this work, the possible application of CSL as a growth stimulant and fertilizer was assessed in soybean plants. We found that treatment with low concentration of CSL significantly improved the germination rate of soybean seeds. After 36 h, the germination rate (69%) of soybean seeds treated with 1% CSL was almost two times of that (35%) of the control seeds. After 84 h, the germination rate (95%) of soybean seeds treated with 1% CSL was still 12% higher than that (83%) of the control seeds. Treatment with 1% CSL also increased soil pH and optimized the availability of nutrients in the rhizosphere, leading to promoted vegetative growth and earlier flowering of soybean plants. Further studies revealed that the expression level of some nutrient absorption and transport related genes in the roots of soybean plants treated with 1% CSL was remarkable higher than that in the roots of control plants. All these results demonstrate that CSL can be used as a potential stimulant and fertilizer to increase the growth rate of soybean plants.