CHANGES IN ROOT-GROWTH PATTERNS OF (PICEA-ABIES) SPRUCE ROOTS BY INOCULATION WITH AN ECTOMYCORRHIZAL FUNGUS PISOLITHUS-TINCTORIUS AND JASMONIC ACID TREATMENT

Symbiosis between fungi and plant roots forming a mycorrhiza involves extensive interactions at the molecular level between both partners. T he role of plant hormones in the regulation of mycorrhizal infection i s not known to involve jasmonates. Their endogenous levels increase du ring pathogen attack: however, little has been done on their involveme nt in mycorrhizae. In our recent work, root growth patterns of 2-month -old spruce seedlings after (JA) inoculation with Pisolithus tinctoriu s and/or jasmonic acid (JA) treatment were studied using a paper-sandw ich technique. Changes in root length, the degree of branching, presen ce and length of root hairs, and infection parameters were followed us ing a stereomicroscope. The first mycorrhizal contact of hyphae with r oots was significantly accelerated upon treatment with 0.5 mu M JA, In teractions between root hairs and fungal hyphae were seen by scanning electron microscopy. The multiplication of root hairs of non-mycorrhiz ed seedlings treated with 5.0 mu M JA and changes of the root surface were observed by the same technique.