Growth responses of Ailanthus altissima seedlings to SO2

Growth of Ailanthus altissima (Mill.) Swingle seedlings exposed to various levels of sulphur dioxide (SO2) was observed. Exposure for 1 or 2 weeks at 260 [mu]gm-3 (0[middle dot]1 ppm) or 520 [mu]g m-3 (0[middle dot]2 ppm) of SO2 significantly (p 2 concentration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24357/1/0000626.pd

Variation in mating competence and random amplified polymorphic DNA in Laccaria bicolor (Agaricales) associated with three tree host species

We examined the population genetic structure of the ectomycorrhizal fungus Laccaria bicolor (Maire) Orton using single spore homokaryotic cultures from 33 basidiomes collected in northern Minnesota in association with red pine (Pinus resinosa Ait.), jack pine (Pinus banksiana Lamb.), and trembling aspen (Populus tremuloides Michx.) of three age-classes (0–20 years, 21–40 years, and \u3e 41 years). Mating competence between cultures of isolates, as determined by the presence of clamp connections, revealed the presence of two subpopulations that were not freely interbreeding, one composed of 29 dikaryons, the other of 3 dikaryons. Phenetic cluster analysis using random amplified polymorphic DNA markers did not reveal differentiation between these subpopulations. Clustering failed to reveal genetically distinct groups based on incompatibility group, tree host species, or geographic origin of isolates. Key words: heterogenic incompatibility, RAPD, population genetics