摘要:

Decay results in appreciable losses in sound wood volume in sugar maple (Acer saccharum, Marsh.) timber in the Ottawa–Huron and Algoma Extension Forest region of Ontario. Seventy-four per cent of 606 sample trees had some measure of decay. Twenty-eight fungi were found to be associated with decay in living trees. The most important of these areArmillaria mellea(Vahl ex Fr.) Quél.,Polyporus glomeratusPeck,Ustulina vulgarisTub,Fomes connatus(Weinm.) Gill.,Hydnum septentrionaleFr.,Corticium vellereumEll. & Crag.,Pholiota spectabilisFr., andFomes igniarius(L. ex. Fr.) Gill. Several species previously unreported in the literature were found to be associated with decay in sugar maple in Ontario.Armillaria melleais the most serious butt-decay fungus andP.glomeratusis the most important trunk-rotting species. Frost cracks are the most important courts of entry for decay fungi. Various discolorations occur in sugar maple. The average extent of decay in living trees is estimated according to the occurrence of sporophores ofF.connatus,F.igniarius,H.septentrionale, andU.vulgaris. The incidence and volume of decay increased progressively with age and diameter. One hundred and nine species of Basidiomycetes are tabulated as occurring on living and dead sugar maple in Ontario.

ISSN:0008-4026    

DOI:10.1139/b54-021

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Four species of the Thelephoraceae,Stereum sulcatumBurt,Vararia granulosa(Pers. ex Fries) Laurila,Corticium furfuraceumBres., andTrechispora raduloides(Karst.) Rog. have been found to produce conidia on both simple-septate, haploid mycelia and clamp-bearing dicaryotic mycelia. The conidia of the first three species are borne on oedocephaloid conidiophores while those of the fourth are formed sympodially. In all four species, the conidia, whether produced on haploid or dicaryotic mycelia, are uninucleate and each germinates to give a simple-septate, haploid mycelium. Interfertility tests were undertaken with monosporous cultures derived from the germination of single conidia or of single basidiospores. By pairing single basidiospore cultures from an individual fruit body of bothStereum sulcatumandVararia granulosa, it was shown that these species exhibit a bipolar type of interfertility. For each of the species under investigation, complete interfertility was obtained in pairings between single conidium cultures from different isolates of the same species. A series of single conidium cultures for each species, derived from conidia borne on a dicaryotic mycelium, when paired in all possible combinations, fell into two groups on the basis of their ability to produce clamp connections. InS.sulcatum, members of each group of single conidium cultures were interfertile with one or other of the two types of single basidiospore cultures from the same isolate. Cytological studies show that there is no fusion of nuclei prior to conidium formation on the dicaryotic mycelium. Instead, the two nuclei of the dicaryon divide separately to produce approximately equal numbers of each type of nucleus, one of which enters each conidium. As indicated by the interfertility tests, the conidia therefore contain nuclei of two reaction types which are identical with those of the two nuclei of the dicaryon and also with those of the nuclei of the parent basidiospores.

ISSN:0008-4026    

DOI:10.1139/b54-022

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

An interchanged chromosome and also a telocentric chromosome arose in the progeny of a monosomic wheat plant. The telocentric was recognized by its morphology and the interchange was inferred from quadrivalent and trivalent chromosome associations. Since the interchange affects one of the same chromosomes as the misdivision which gave the telocentric, the interchange is assumed to result from the fusion of two telocentrics from nonhomologous chromosomes.

ISSN:0008-4026    

DOI:10.1139/b54-023

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The microscopic wood structure of nine species ofCupressusnative to Arizona and California was studied from approximately 700 samples. Tracheid and ray cell dimensions, size and distribution of rays, size and arrangement of pits, and thickness of cell walls were found to vary in different parts of the tree, the trends resembling those in other Cupressaceae. Comparisons of the data relating to homologous wood samples revealed slight interspecific differences in mean values for some structural features, but the range of intraspecific variability was usually broad. No single microscopic character was discovered which alone could be considered reliable for species differentiation, but certain features such as the frequency of rays, size of crossing field pits, size of tracheids and ray cells, and thickness of ray cell walls may prove valuable for diagnostic purposes when used together. As in the case of morphological characteristics, species differentiation apparently rests upon slight differences in several characters rather than invariable or marked divergence in single features.

ISSN:0008-4026    

DOI:10.1139/b54-024

出版商:NRC Research Press    

年代:1954

数据来源: NRC

ISSN:0008-4026    

DOI:10.1139/b54-025

出版商:NRC Research Press    

年代:1954

数据来源: NRC