The Extractives of the Mycorrhizas and Roots of Pinus Radiata and Pseudotsuga Menziesii

Abstract

The amounts of acetone extractives from mycorrhizas and their polyphenolic portion were variable over a 6·month period. During August the amounts of extrac· tives and polyphenols were higher in slow· than in fast-growing Pinus radiata seedlings. The amount of extractives in the roots were greater than those in the mycorrhizas but in the latter the polyphenols were concentrated in the outer layer. The composition of the mycorrhizal and root extractives of P. radiata were very similar and in addition to resin contained catechin, two components that are very similar to 3,5,3',4'.tetrahydroxystilbene and one of its glucosides, and leucocyanidin polymers. The mycorrhizas of Pseudotsuga menziesii contain 15 components, includ· ing catechin, epicatechin, leucocyanidin polymers, and a polyene. With the exception of the latter the roots of Ps. menziesii contained the same components and in addition poriolin, poriol, taxifolin, taxifolin-3·glucoside, and quercetin.3.glucoside. Evidence supports the view that the polyphenols are formed in situ and appear to be formed in enhanced amounts in the tannin layer of mycorrhizas. Their possible role in the establishment of mycorrhizas is discussed.