Synthesis of xylan and lignin based hydrogels and their use as growth media for rice (Oryza sativa)

Different hydrogels were synthesised using lignin and xylan (extracted from rice straw) as the raw material, PVA as matrix template, citric acid, and succinic acid as crosslinkers and were structurally characterised by FT-IR and SEM analysis. Citric acid cross-linked hydrogels caused loose bonding between polymers and resulted in formation of large pores whereas succinic acid cross-linked hydrogels were observed to have less porosity and tight bonding network. The swelling ratio and reswelling capacity of hydrogels revealed that lignin hydrogels outperformed all other hydrogels. All the synthesised hydrogels were tested for their use as soil culture media ingredient for the germination of rice seedlings. All the hydrogels performed well in stress conditions as compared to normal conditions. Xylan/lignin hydrogel and lignin hydrogels performed best under stress conditions. These hydrogels could be used effectively as an ingredient of soil culture media owing to their tendency to absorb and retain water properly.