Macroporous scaffold of chitosan as soilless medium for seed germination and seedling growth

The preparation of soilless medium for the growth of seeds based on macroporous scaffolds of chitosan-glutaric acid and urea (CHGAUR) is reported. The CHGAUR scaffold was prepared by the hydrothermal reaction of chitosan with GA in presence of urea. The product was purified using Soxhlet extraction with methanol. CHGAUR was composed of chitosan with a small weight fraction of glutaric acid and urea, which were present in the salt form as confirmed by TGA and FT IR spectroscopy. This suggested that CH is most likely to be physically crosslinked in the scaffold through GAUR links. SEM images confirmed the porous structure of material. Water absorption studies suggested that CHGAUR could absorb ∼4100-5700 % water and could be varied by varying the CH: UR ratio used in the preparation. The percentage porosity of CHGAUR did not vary much with urea content suggesting that significant variation in the micropore structure was not obtained by varying the urea content in the preparation. Mechanical tests revealed that material was soft and flexible and able to retain its original shape even after removing the load. CHGAUR, in purified state, was studied for the germination and seedling growth. Among the seeds investigated, pigeon pea showed the best result.