The water‐soluble carbohydrates of grasses. III.–first and second year growth

The water‐soluble carbohydrates, glucose and fructose (reported together as total free hexoses), sucrose and fructosan have been determined in eight strains of rye‐grass of varying rates of growth and in two strains of timothy and one of cocksfoot in their first and second years of growth. In the rye‐grasses, the extremely rapid growth and flowering of annual varieties resulted in much smaller accumulations of fructosan but more free hexoses than in biennial or perennial plants. Flower formation in the timothy grasses in the first year similarly delayed the storage of fructosan until after head emergence. In second‐year growth the fructosan content of all species increased rapidly early in the year but flower formation and early development caused a marked fall in the fructosan content of the timothy and cocksfoot strains but not of the rye‐grasses. The reverse was later true during stem elongation after flower emergence, when the fructosan content in the rye‐grasses fell sharply whilst those of the timothy grasses and cocksfoot rose to a second peak. The practical aspect of this difference in the soluble carbohydrate content of grasses at similar stages of growth is mentioned.