Comparison of ergosterol and chitin as quantitative estimates of mycorrhizal infection and Pinuscontorta seedling response to inoculation

Abstract

The ergosterol and chitin content of 35-week-old Pinuscontorta var. latifolia Engelm. roots ectomycorrhizal with Hebelomacrustuliniforme (Bull.:St. Amans) Quél. were compared as indices of intramatrical mycelial mass. Ergosterol analyses were less labor intensive (about one-half) and detected differences in mycorrhizal establishment among P fertilization treatments, whereas differences found using chitin analyses were not statistically significant. Intramatrical mycelial estimates by the two techniques were not correlated (r = 0.15); estimates based on ergosterol were 2–5 times greater than those based on chitin, with the chitin:ergosterol ratio increasing as P fertilization increased. Owing to its sensitivity and specificity, the ergosterol assay is a practical means of monitoring the establishment of ectomycorrhizae in pine roots.