Distributions of the fungal endophyte Acremonium lolii, and of the alkaloids lolitrem B and peramine, within perennial ryegrass

Ryegrass tillers, from a ryegrass staggers-prone pasture, were dissected into constituent live leaves of different ages. Leaves were further divided into three blade and two sheath portions. Acremonium lolii, lolitrem B, and peramine concentrations were determined for each defined portion. The mean % distribution and concentrations of A. lolii and lolitrem B in the sheath were much higher, and the mean % distribution of peramine in the sheath was much lower, than in the blade portions. Within leaves, both the % distribution and the concentration of A. lolii increased progressively from blade tip to lower sheath; the patterns for % distribution and concentration of lolitrem B were similar to those for A. lolii, except that lower sheath values were less than those of upper sheath portions; the % distribution of peramine was higher in the lower blade portions than elsewhere, and peramine concentrations were higher in portions adjacent to the ligule. Within tillers, A. lolii concentrations were lower in the youngest and oldest leaves; peramine concentrations were lower for older than for younger leaves; and lolitrem B concentrations increased progressively from youngest to oldest leaves.