摘要:

The inhibitory power of poplar bark against the growth ofHypoxylon pruinatum(Klotzsche) Cke. was demonstrated on autoclaved bark meal agar. Activity varied with the species, time of cutting, and locality, but was highest in the bark ofPopulus tremuloidesMichx. Maximum activity occurred in the roots and decreased towards the top of the tree. Neutral, basic, and acid fractions obtained from active ethyl acetate extracts of aspen bark showed seasonal quantitative variations which were characteristic for each fraction and for the part of the tree sampled. The acid fraction contained three active compounds: pyrocatechol, an undetermined phenol, and a glycoside (R). The neutral fraction contained an active glycoside (W). Glycoside (R) was mainly concentrated in the lower stem and glycoside (W) in the upper stem. The concentration of the two glycosides in the bark varied with locality. The influences of pH, temperature, and different chemicals on the fungistatic action of pyrocatechol were investigated to elucidate their rôle in disease resistance. In wilting tests, poplar leaves showed a light necrosis at 1320 p.p.m. of pyrocatechol, whereas 165 p.p.m. were lethal to tomato plants.

ISSN:0008-4026    

DOI:10.1139/b66-046

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The chromosome numbers of 23 species of the Arundinelleae (Gramineae) are recorded. In the present study 40 new counts are given, together with the 28 obtained from the literature. A discussion of the cytological variability of the tribe points out factors relevant to the latest classification of the group.

ISSN:0008-4026    

DOI:10.1139/b66-047

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Three main categories of culture characteristics were examined: gross morphology of the growing colony, microscopic morphology of the mycelium, and chemistry of the mycelium as expressed by color changes induced by specific chemical reagents. The diagnostic characteristics for the three species studied have been arranged into a numerical key that is amenable to expansion as data for more species become available.

ISSN:0008-4026    

DOI:10.1139/b66-048

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

In osmium-fixed, Epon-embedded root meristematic cells ofVicia fabastained according to the Feulgen – methylene blue procedure, the interphase nucleolus is seen to consist of a metachromatic cabbage-green colored material in which are embedded numerous unstained vacuole-like structures of varying size. By using an orange Wratten filter in the illumination system, it is observed that the metachromatically stained nucleolar material is, in fact, made up of two components, each segregated into zones distinguishable by differences in staining intensity. The first more lightly stained component is found in the central and bordering regions of the nucleolus as well as in a number of areas of varying width extending radially in between them. The second more intensely stained component is observed in areas of varying length and width usually occupying the intermediate regions of the nucleolar mass. Under electron microscopy, the first component is seen to consist of densely packed fibrils and granules some 150 Å in diameter; in places, those constituents are assembled into seemingly coarse, thread-like structures approximately 0.1 μ in diameter. The second component, on the other hand, is made up mainly, if not exclusively, of tightly packed fibrils 60 to 100 Å in diameter. Judging from their topographical distribution and ultrastructural characteristics, it would seem as if the two nucleolar components just described correspond respectively to what is usually referred to as nucleolonema and pars amorpha in animal nucleoli. In addition to nucleolonema and pars amorpha, two ultrastructurally and topographically distinct types of vacuole are recognizable within the interphase nucleolus ofVicia faba. The vacuoles of the first type are usually large or medium-sized, contain loosely and uniformly scattered fibrils and granules approximately 150 Å in diameter, and are observed exclusively within the nucleolonematic zones of the nucleolus. The vacuoles of the second type are small, contain only loosely dispersed fibrils, 60 to 100 Å in diameter, and are confined to the pars amorpha of the nucleolus.

ISSN:0008-4026    

DOI:10.1139/b66-049

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Segments taken from the roots and shoots of healthy 1-year-old seedlings of Douglas fir (Pseudotsuga menziesii(Mirb.) Franco) collected over a 2-year period from two British Columbia forest nurseries, were surface-sterilized, and incubated on various media. Fungi grew from segments of over 80% of the seedlings, the most frequent beingFusarium oxysporumSchlecht.,F. redolensWr.,Mycelium radicis atrovirens, Cylindrocarpon didymum(Hart.) Wollenw., andC. radicicolaWollenw. Fungi were isolated more frequently from the shoot than from the root segments. Isolations from segments with the bark intact were more frequent than from segments that had the bark removed. Seedlings collected in the winter produced more fungi than those collected during the summer. Segments from diseased seedlings and seedlings grown under sterile conditions produced mycofloras which were different from each other and from that of healthy nursery-grown seedlings. Without exception, fungi grew from surface-sterilized seed placed on malt agar and samples from different seedlots had different floras. Stained sections clearly showed hyphae and chlamydospores well within the tissue of roots, shoots, and seed coat.

ISSN:0008-4026    

DOI:10.1139/b66-050

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Phragmites communis, Eriophorum vaginatum, Calluna vulgaris, andSphagnum palustreare representative of plants whose remains are frequently encountered in Scottish peat deposits. The effects of preservation in peat on the surface features of their leaves were followed by electron microscopy. Wax projections were observed on the surfaces of mature living leaves ofPhragmitesandEriophorumbut not onCallunaorSphagnum. Details of cell wall outlines and stomata (or pores) were clearly defined inPhragmites, Eriophorum, andSphagnum, but obscured inCalluna. The previous year's leaves differed by displaying a general absence of wax projections, an erosion of the cuticular surface, which took the form of either a loss in definition of the cell wall outlines or a definite etching of the surface, and the presence of numerous microorganisms. The surface features of preserved leaves exhibited to a greater degree this erosion of cell wall outline and cuticular surface. This preliminary study has indicated that major alterations in the submicroscopic features of cuticularized leaf surfaces occur at the leaf litter stage. The primary agents responsible for this degradation would appear to be microorganisms in conjunction with the physical and chemical processes of peat formation.

ISSN:0008-4026    

DOI:10.1139/b66-051

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Chromosome numbers are reported for 93 taxa from central northern Canada. It is pointed out that the collective speciesDupontia fisheriactually includes three species differing in chromosome number, viz.,D. psilosantha(2n = 44),D. pelligera(2n = 88), andD. fisheris. str. (2n = 132). The taxon often namedCarex saxatilisvar.majoris identified withC. physocarpawith 2n = 60 chromosomes whereasC. saxatiliss. str. has 2n = 80. Two new combinations are proposed:Argentina anserinass.EGEDII(Wormskj.) Löve & Ritchie, andMenyanthes trifoliatassp.MINOR(Raf.) Löve&Ritchie.

ISSN:0008-4026    

DOI:10.1139/b66-052

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Cunninghamella vesiculosaMisra, a new species isolated from sal forest soil of Gorakhpur, India, is described and illustrated. The species is characterized by peculiar apically fertile and slightly constricted vesicles and by unusually long spines on the conidia.

ISSN:0008-4026    

DOI:10.1139/b66-053

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The genus nameFlageoletia(Sacc.) Höhn. is shown to be a synonym of the genus namePhomatosporaSacc. Three of the four described species,Flageoletia leptasca(Pk. & G. W. Clint.) Höhn.,Flageoletia tenuis(Sacc.) Höhn., andFlageoletia rehmianaHöhn. are synonymous and assigned toPhomatospora leptasca(Pk. & G. W. Clint.) J. Reid & Booth comb. nov. The fourth species,Flageoletia bambusinaSyd. represents an undescribed genus and is herein designatedNeoflageoletia bambusina(Syd.) J. Reid & Booth, comb, nov., the type species of the new genus,NeoflageoletiaJ. Reid & Booth.

ISSN:0008-4026    

DOI:10.1139/b66-054

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Widths of earlywood and latewood in each annual ring, measured on an average radius on a disk taken halfway between each branch whorl, were analyzed to define their variation in 18 Douglas-fir trees (Pseudotsuga menziesii(Mirb.) Franco). Distribution of ring width and percentage latewood also was investigated in these trees which had from 20 to 50 whorls above stump height. Multiple regression and correlation analyses showed that number of rings from pith, and its reciprocal, square, or logarithm accounted for most of the variation in radial growth. Number of rings from pith influenced thickness of both earlywood and latewood much more than the climatic differences reflected by variations in annual height growth and in widths of earlywood and latewood formed at breast height in the same calendar year. Since earlywood and latewood are distributed differently and controlled by different factors, they should be studied separately within annual rings. The statistical methods used in this study provide a simple, efficient, and comprehensive basis for thoroughly describing growth patterns, and for objectively analyzing factors that govern growth.

ISSN:0008-4026    

DOI:10.1139/b66-055

出版商:NRC Research Press    

年代:1966

数据来源: NRC