Published online by Cambridge University Press: 27 March 2009
Features of the gross morphology of primary growth of Dactylis glomerata and Lolium perenne, and associated changes in digestibility are described.
Species differences were noted with regard to the relationships between head emergence and the time when stem apices were raised to defoliation height, vegetative/ reproductive tiller ratios, and tiller size.
Also there were differences in the sequence of extension growth of leaf sheaths, internodes and inflorescence leading to emergence of the head. Associated changes in the vertical distribution of leaf blades were examined.
In perennial ryegrass extension growth of the inflorescence continued after emergence had begun, but not in cocksfoot. Weight increments in the inflorescence, from emergence onward, followed the same pattern in the two species, however.
Differences in the developmental patterns of the two grasses did not appear to influence their relative digestibility.
Upper internodes of reproductive tillers of S. 24 ryegrass declined rapidly in digestibility Species differences, and the pattern of changes in the digestibility of lower and upper parts of reproductive tillers are discussed in relation to mechanical aspects of sward development and micro-environmental effects.