Changes in cell-wall carbohydrates and lignin of some forage-type millets as affected by growth stage

Changes in the cell-wall carbohydrates and lignin of bajra (Pennisetum typhoides), jowar (Sorghum vulgare) and napier (Pennisetum purpureum)–bajra hybrids (NB₂₁) as affected by growth stage are reported. With growth of the plants the concentrations of α-cellulose and hemicellulose increased in the stems. In bajra and jowar this increase was gradual up to 60–70 days growth stage followed by a decline and a subsequent rise towards maturity. In contrast, in NB₂₁, α-cellulose continued to rise gradually throughout the growth period. The concentration of hemicellulose was much higher in the stems than in the leaves of NB₂₁. With the ageing of the plants the lignin content increased in all these forage crops. In NB₂₁ the stems contained more lignin than the leaves at all stages of maturity. Fluctuations in the contents of lignin, cellulose and hemicellulose followed similar trends indicating that possibly they are components of a common matrix in the cell wall. In NB₂₁ the water-soluble carbohydrates continued to rise throughout the growth period unlike other forage crops. The protein content decreased as the NB₂₁ plants matured. The protein content of the leaves of these plants was always higher than that of the stems. The oxalates gradually declined with the maturation of the plants.