摘要:

Two equal-area projection techniques (point diagrams and contoured density diagrams) are presented for use in analyzing three-dimensional leaf orientation data. The diagrams display both azimuths and inclinations simultaneously, and allow a rapid visual evaluation of the data. Leaf orientation measurements from three specimens ofNerium oleanderare used to illustrate the techniques.In addition, the point diagram permits the grouping of data from a particular canopy layer into regions, simultaneously considering both azimuths and inclinations as well as leaf area. The contoured density diagram allows these regions to be selected on the basis of the actual distribution of leaf area.

ISSN:0008-4026    

DOI:10.1139/b73-136

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Conidium ontogeny inCladosporium herbarum(Pers.) Link ex S. F. Gray andTorula herbarum(Pers.) Link ex S. F. Gray is analyzed by time-lapse photomicrography. Both fungi are shown to produce conidia holoblastically in acropetal chains.

ISSN:0008-4026    

DOI:10.1139/b73-137

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Developmental studies do not confirm the general opinion that the androecium or the gynoecium is spiral inSagittaria latifolia. After the inception of three sepal primordia, three bulges (petal–stamen primordia) are formed on radii alternating with the sepal primordia. On each petal–stamen primordium a petal is initiated and subsequently a pair of stamens in the male floral bud and staminodia in the female floral bud. Next, two antesepalous primordia are formed between the first paired primordia. Further stamens (or staminodia and carpels in the female floral bud) are formed centripetally, more or less alternating with the previous ones at subsequently higher levels.

ISSN:0008-4026    

DOI:10.1139/b73-138

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Aboveground green biomass of a montane pure stand ofCarex rostratavaries from about 125 g/m2(air-dry weight) at the end of November to about 640 g/m2in early August. The maximum production rate of about 6 g/m2per day occurs in May. For a nearby stand ofCarex aquatiliswith a prominent moss layer the aboveground green biomass of sedge material varies from about 40 g/m2in February to about 380 g/m2in mid-August. The maximum production rate for sedge material is about 4 g/m2per day in July. Both species exhibit two main populations of shoots, one emerging in late summer and the other through winter and early spring. The winter and spring shoots ofCarex rostrataflower and die after about 18 months, while the late summer shoots, which do not mature vegetatively until the following summer, have a life-span of about 2 years. The late summer shoots ofCarex aquatilismature vegetatively before winter, and flower and die within about 12 months; while the winter and spring shoots live through the next winter, and flower and die the following summer after a life-span of about 18 months.

ISSN:0008-4026    

DOI:10.1139/b73-139

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A method has been adapted to follow quantitatively the uptake ofL-alanine-14C, and presumably other14C-labeled compounds, into soybean (Glycine max. cv. Mandarin) root cells growing in sterile suspension culture. Details are given of the growth and assay requirements needed to yield reproducible data.When alanine-14C uptake is followed into cells grown in the presence of nitrogen until immediately before assaying, a double reciprocal plot of velocity against alanine concentration yields a straight line which passes through zero, indicating that increasing substrate concentration will not saturate this uptake system. When cells are starved of nitrogen for 12 h before they are assayed, uptake rates increase by more than 100 times and a substrate-saturable uptake system can be detected. AKmvalue of 2.55 × 10−6 M was calculated. This saturable system is also strongly and rapidly affected by the respiratory inhibitors 2,4-dinitrophenol (DNP) and sodium azide.

ISSN:0008-4026    

DOI:10.1139/b73-140

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A modified version of the Braun–Blanquet technique for the analysis of plant associations was applied to an area of lichen-dominated raised-beach system near Cape Henrietta Maria in subarctic northern Ontario. Eleven plant associations were extracted which appear to follow ecological gradients related to water availability, soil pH, and the presence/absence of a peaty substratum. It was concluded that this type of association analysis fulfilled all the major objectives of a preliminary survey.

ISSN:0008-4026    

DOI:10.1139/b73-141

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Three hyphomycetes collected on litter in India are described:Kramasamuha sibikagen. et sp. nov.,Sympodiella laxasp. nov., andZanclospora indicasp. nov.

ISSN:0008-4026    

DOI:10.1139/b73-142

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The responses of 15 weeds (Agropyron repens, Centaurea cyanus, C. jacea, Chrysanthemum leucanthemum, Cirsium arvense, C. vulgare, Daucus carota, Erigeron canadensis, Euphorbia cyparissias, E. esula, Nasturtium officinale, Neslia paniculata, Plantago major, Silene cucubalus, Vicia angustifolia) to eight herbicides were considered in relation to the level of ploidy, the life form, the nuclear volume, and the interphase chromosome volume, for each species. In general, susceptible weeds had a lower nuclear volume than those showing an intermediate or a resistant response to the herbicides. Interphase chromosome volume did not show any consistent relationship with the degree of susceptibility. Intermediate and resistant plants were mostly perennials, whereas susceptible ones were annuals or biennials.

ISSN:0008-4026    

DOI:10.1139/b73-143

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The mitotic cycle can be arrested in the apical summit of vegetative terminal buds ofTradescantia paludosaby restricting the level of nitrogen or light available to the plant. Cells in this portion of the bud are much more sensitive to these stress conditions than those in the subjacent portion of the meristem. This differential response induced the establishment of a quiescent "central zone" which is distinguished from the rest of the meristem by the apparent absence of mitosis and DNA synthesis, larger nuclear volume, and a lower histone content of chromatin. These features are identical with those imposed by apical dominance in apices of inhibited lateral buds.The results support the view that competition for nutrients is an important causal factor in apical dominance. They suggest also that competition for nutrients within the terminal bud meristem is important in the regulation of growth in vegetative shoots in respones to conditions of the environment.

ISSN:0008-4026    

DOI:10.1139/b73-144

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The composition of the cell walls of synnemal and vegetative hyphae ofCeratocystis ulmiwas studied by fractionation and assay of released compounds. Residues after enzymatic hydrolyses were examined by electron microscopy. The synnemal wall was found to have 67% carbohydrate, 4.52% amino sugar, 5.02% protein, 1.6% lipid, and 0.59% ash, which accounted for 78.7% of the cell wall. The vegetative hyphal wall contained 56% carbohydrate, 3.44% amino sugar, 7.92% protein, 4.5% lipid, and 1.45% ash, which totaled 73.3% of the wall weight. Sugars identified wereD-glucose,D-mannose,D-galactose, andL-rhamnose. Enzymatic hydrolysis of both wall types by cellulase and laminaranase indicated the presence of beta-1,3 and beta-1,4 linkages of glucose polymers. N-acetylglucosamine was liberated by chitinase. Most of the 16 amino acids detected in each wall type were at least twice as abundant in vegetative hyphal walls as in synnemal hyphal walls. Cellulase and laminaranase treatment of cell walls revealed a fibrillar structure. Chitinase-treated walls did not appear as fibrous, suggesting that the fibrous structure may be mostly chitinous. Synnemal cell walls are covered by electron-dense granules which may correspond to the pigment in the synnemal hyphae.

ISSN:0008-4026    

DOI:10.1139/b73-145

出版商:NRC Research Press    

年代:1973

数据来源: NRC