Search

Single isolates of six ectomycorrhizal fungi (Amanita rubescens, Cencoccum graniforme, Rhizopogon roscolus, Russula emtica, Suillus cothurnatus and S.punctipes ) substaially increased dry weight on the aldohexoses D-glucose and p(+) mannose and the heteroglycan pectin among 52 compunds used as sole carbon sources. The pectin may have been impure. One to five isolates also grew well on the ketohexose fructose; the hexose alcohols mannitol and sorbitol; the disaccharides cellobiose, D(+)maltose and D(+)trehalose and the soluble homoglycans dextrin glycogen, insulin and starch . Utilization of the heterogeneous disaccharide sucrose, depend upon length of time and the concentration. There was relatively greater growth with 4 and 8 g of carbon equivalent than with 2 g. Doubling the carbon equivalent of usable sugars did not double dry weight. [ABSTRACT FROM AUTHOR]

This article features a study regarding volatile organic compounds in mycorrhizal and non mycorrhizal root systems of Pinus echinata Mill. Infection of feeder roots of Pinus echinata by the ectomycorrhizal fungus, Pisolithus tinctorius, resulted in an approximate 40-fold increase in the level of 3-carene, and Cenococcum graniforme induced an approximate 30-fold increase in phellandrene. Vapors of these volatile compounds affected the vegetative growth of different ectomycorrhizal and root pathogenic fungi to different degrees in laboratory experiments.

This article presents various study reports analyzing growth inhibition of two root pathogenic fungi by volatile organic constituents of ectomycorrhizal root system of Pinus sylvestris L. By using the gas phase analysis, all the monoterpenes and the sesquiterpene longifolene have been identified as responsible inhibitors. The article investigates to determine the effect of these chemical inhibitors on the mycelial growth of those two phytogenic pathogens. The procedures used for testing the volatile host constituents and the volatile metahohtes of Boletus variegatus were slightly different from each other. Tests with monoterpenes and the sesquiterpene longifolene were performed in glass petri plates with 15 ml of medium per plate.

The action of excised roots on the growth of tree mycorrhizal fungi has been studied. Roots of Lepidium sativum, Medicago sativa, Cannabis sativa, Triticum aestivum all produced metabolites which increased the growth rate of Boletus variegatus and B. elegans in a nutrient medium containing sugar, salts, B-vitamins and amino acids. Pea roots initially had a growth-promoting influence on Rhizopogon roseolus but alter some time they caused a strong growth-inhibiting effect on this fungus. The experiments seem to show that the growth-promoting root metabolites concerned, conveniently called factor M, are not specific for certain roots, hut occur in a great number of plants little related to each other. The magnitude of the growth-promoting root effect is very different for different tree mycorrhizal fungi. The results indicate that Boletus variegatus and Rhizopogon roseolus are only partially deficient for the M-factor, whereas Russula xerampelina may be totally, or nearly totally, deficient. [ABSTRACT FROM AUTHOR]

This article presents a study regarding the production by roots of Calluna vulgaris. It discusses that tree species, including spruce Picea abies and birch Betula pendula, frequently fail to develop in association with heather, Calluna vulgaris. The affected trees exhibits no pathological symptoms and making little measurable growth. The lack of growth is characteristic of both shoots and roots in which the shoots fail to form any mycorrhizal associations. Moreover, the poor development of uninfected roots is due to phytotoxic metabolites in the Calluna raw humus.

Presents a correction to an article about ectomycorrhizal fungi in pure culture, previously published in the journal "Physiologia Plantarum."