High-transmittance Soil Colloidal Disperse System for in situ Root Phenotype

Background and Aims Root phenotype is vital to the acquisition of water and nutrients from culture media. Acquiring root phenotype accurately and efficiently is still very challenging due to the opaque of soil and low agronomic relevance of hydronics. Recently, the physical structure of the culture medium has been proposed to exert an effect on root phenotypes, whereas the impact of nutrients tends to be overlooked. Methods With hot water extraction and freeze-thaw treatment, we prepared high-transmittance soil extract containing soil colloids to fulfill in situ root phenotype, which is specially designed for restoring the soluble and adsorbed nutrients in soil for plants. We analyzed the phenotype of soybeans cultured in traditional hydronics media, soil and soil extract to evaluate the effects of nutrients on phenotype. Results The inorganic and organic nutrients was extracted successfully. After freeze-thaw, and soil extract the transmittance of SCDS has increased by 24% in the range of visible light wavelength with negligible effects on the content of nutrients, making in situ root phenotype practicable. Compared to traditional hydronic media, the most root phenotype of soybean cultured in soil extract are more similar to that of soil. Conclusion SCDS can restore the available nutrients of soil for plants. This work provides a novel hydronic culture media to realize accurate in situ root phenotype.