Does Endophyte Influence Regrowth of Tall Fescue?

• DOI: 10.1006/anbo.1996.0147
• Publication Date: 2002-10-07T17:28:30Z
• Authors: D BELESKY
• Keywords: 0401 agriculture, forestry, and fisheries; 04 agricultural and veterinary sciences; 15. Life on land

Abstract The influence of ecological and environmental factors on the response of the mutualistic symbionts Acremonium coenophialum (Morgan-Jones and Gams), and tall fescue ( Festuca arundinacea , Schreb.) has received substantial attention. However, much of what is known about developmental and physiological responses has been obtained from static or mature canopies and the influence of defoliation on the symbiota has not been considered in detail. A controlled environment experiment was conducted to assess the influence of defoliation and endophyte on the regrowth and development of two tall fescue genotypes and their respective endophytes, known to differ in morphology and alkaloid production capacity. The response of endophyte infected relative to non-infected plants was evaluated for measured and calculated parameters for each defoliation. While the influence of genotype was substantial on virtually all parameters, endophyte interacted with genotype and defoliation resulting in enhanced plasticity of mutualists as a response to varying conditions. Endophyte infection influenced leaf mass depending upon genotype, while the relative benefit of endophyte on pseudostem mass was affected by defoliation. Endophyte interacted with genotype to influence relative growth rate and productivity relative to nitrogen concentration when canopies were clipped, but was less important when canopies remained uncut. In some instances endophyte gave growth and size advantage to the host and did not in others. Generalities regarding symbiont response to extrinsic factors may be misleading, since responses depend upon the specific mutualism considered and conditions imposed.