摘要:

Incipient and advanced tumors were present in the hypocotyl and the first three internodes of severely stunted, 10-node plants ofGossypium hirsutum×G.gossypioideshybrid. Tumors, free of bacteria or fungi, were initiated at or near the vascular cambium as small clumps of hypertrophied parenchyma. Disorganization of segments of the vascular cambium occurred in association with tumor initiation. Subsequent growth of tumors caused disorganization of the phloem and formation of wedge-shaped masses of tumorous parenchyma in the xylem. Isolated tumors occurred in the pith of 14-node plants.The stem xylem of tumorous 10-node plants had increased levels of the flavanols catechin and gallocatechin, normally present only in a few scattered parenchyma cells in nontumorous xylem tissue. Several terpenoid aldehydes, predominantly hemigossypol and methoxyhemigossypol, occurred in tumorous xylem tissue, but were absent in nontumorous tissues. Histochemical reagents showed that the flavanols and terpenoid aldehydes were associated with incipient and advanced stages of tumors in the stem xylem.

ISSN:0008-4026    

DOI:10.1139/b81-130

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The water content, water potential, osmotic potential, and turgor pressure relationships of two cultivars of indoor-grown cassava (Manihot esculenta) were examined. The two cultivars (CMC9 and MCOL113) represent low and high starch yielding varieties, respectively.Leaf water potentials were measuredinsituwith a dew-point hygrometer. A pressure chamber was used to estimate ψLin excised leaves. Relative water content (RWC) of intact leaves was measured with a beta-gauge but was calculated from the pressure chamber data for excised leaves. Osmotic potentials at water contents between 0 and 100% were calculated and the corresponding turgor pressures were obtained by difference.At low soil moisture tension, RWC and ψLdropped to minimum values during the day but recovered considerably at night. Osmotic potentials of turgid leaves were −970 kPa in cv. CMC9 and −1000 kPa in cv. MCOL113. Diurnal variations ψπwere small in both cultivars. However, daily fluctuations in ψPwere larger and paralleled changes in ψL. A marked hysteresis was evident in the water content-potential and the water content-turgor pressure data obtained during the drying cycle. However, when water potentials and turgor pressures were changed rapidly by switching the lights off and on at short-time intervals, no hysteresis was observed in the data.

ISSN:0008-4026    

DOI:10.1139/b81-131

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The standard water bubbler and a modified tower aspirator for quantifying ascospore productivity were compared. Samples, each consisting of 50 discs, were cut randomly from scab-infected McIntosh apple leaf litter in the spring and 18 samples were processed by each method. The square roots of hemocytometer counts adjusted for unit area or gram dry weight of leaf samples were found to be normally distributed. More spores were harvested from the same amount of leaf material with the bubbler than with the tower. The coefficient of variation for spore yields expressed on a per area or a per gram dry weight basis was smaller for the tower method than for the bubbler, although the values were not significantly different. Where detection of low ascospore productivity is not essential, the tower method is preferable in terms of ease, speed of operation, and the potential for electronic enumeration of harvested ascospores.

ISSN:0008-4026    

DOI:10.1139/b81-132

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Root tips (1 cm long) were excised fromin vitrogrown plants ofLimnophila indica(L.) Druce and cultured in liquid medium with 2% sucrose. The explants floated horizontally on the surface of the medium; they became green, and their tips started to grow geotropically into the medium. Four to six shoot buds each were differentiated in 84.5% of the cultures in 4 weeks. Subsequently, shoot buds covered the surface of the bent part of the root and portions above and below it. No buds were formed at the cut end or near the growing root tip. Buds failed to differentiate in roots in which the apex was not growing. Histological studies of the roots showed that the buds originated from proliferating cortical cells, which had prominent chloroplasts and starch grains. The shoot buds grew into entire plants which flowered eventually.

ISSN:0008-4026    

DOI:10.1139/b81-133

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The development of the laticifers of the primary system in the roots of young seedlings ofHeveais investigated. The nucleus of the maturing secretory cells progressively diminishes in size, thus giving rise to a dense "pycnotic" body. Plastids of primary laticifers show an organization intermediate between that of plastids of neighbouring parenchyma cells and that of the Frey-Wyssling complexes of the secondary laticifers. The continuity of the vacuomesensu latois underlined. The lutoids, a specialized form of "polydisperse vacuome," show a relationship with the endoplasmic reticulum; these lutoïds can also incorporate rubber particles. The ontogeny of cell wall perforations is described; a progressive hydrolysis of the wall results in its gradual thinning followed by its disruption. Rubber particles are initiated as discrete inclusions within the protoplasm. A thin surface film is identifiable on them, the staining properties of which change during the maturation of the particles. The protoplasm of adult laticifers is densely packed with rubber particles.

ISSN:0008-4026    

DOI:10.1139/b81-134

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Pestalosphaeria hanseniin.sp. is described fomPinus caribaeaMorelet var.hondurensisBarrett and Golfari needles from Papua New Guinea. Isolations from single ascospores produced aPestalotiopsisin culture that matched cultures derived from aPestalotiopsisassociated with the teleomorph on the pine needles. The new species is contrasted withPestalosphaeria concentrica,P.austroamericana, andP.elaeidis. Discussion of the generic placement of the anamorph involves the namesPestalotiopsis,Pestalotia,Truncatella,Monochaetia,Lennisia,Coryneum,Seiridium, andHyalocera(orHyaloceras).

ISSN:0008-4026    

DOI:10.1139/b81-135

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Sixteen species and one variety of the algal genusCryptomonasEhrenberg were identified from a large number of samples collected from lakes, ponds, and marshes in eastern Canada and the Northwest Territories. A description, including photographs and drawings, is given for each taxon. Cluster analysis statistics were used to determine the taxonomic value of certain characters and the affinities between the species. It was found that binary (two-state) characters gave a more realistic diagnosis than quantitative (continuous) data because of the large variation and overlap in measurements of the latter. The following characters were considered to be of taxonomic significance in separating the species: (i) cell shape and size, (ii) number of chloropasts, (iii) number and position of chloroplasts, (iv) flagella and gullet system, and (v) number and position of other included bodies. Based on these characters, a new taxonomic key was constructed for the identification of the common freshwater species ofCryptomonas.

ISSN:0008-4026    

DOI:10.1139/b81-136

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The algicidal properties of Aerotex 3470, a pesticide cosolvent in several fenitrothion formulations, have been investigated under controlled laboratory conditions. Aerotex (1–100 ppm) inhibited the growth of three unicellular freshwater algae (Chlamydomonas reinhardii,Chlorella pyrenoidosa, andScenedesmus obtusiusculus) on agar plates and in liquid culture. Prolongation of the lag phase was directly related to Aerotex concentration. Algal cultures exposed for 1 h to Aerotex (1–10 ppm) had significantly reduced ATP levels. In all cases (agar, liquid culture, and ATP bioassays),ChlamydomonasandChlorellawere more sensitive to Aerotex thanScenedesmus.Electron microscopy demonstrated gross ultrastructural changes inChlamydomonastreated for 1 h with Aerotex (5 ppm), including swollen mitochondria, disorganization of thylakoids, and crenulation of the cell membrane. Similar membrane damage was caused by 1-methylnaphthalene (5 ppm), a constituent of Aerotex.

ISSN:0008-4026    

DOI:10.1139/b81-137

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The mycorrhizal synthesis betweenDryas octopetalaL. and two Agaricales from alpine area:Hebeloma alpinum(Favre) Bruchet andHebeloma marginatulum(Favre) Bruchet, have been produced in the laboratory. Both fungi yielded normal fructification after 8 months in culture. After light and scanning electron microscopic examination, macro- and microscopical features of these mycorhizae are described. This symbiotic association, existing in the field betweenD.octopetalaand those fungi typical of the alpine area, is discussed from an ecological point of view.

ISSN:0008-4026    

DOI:10.1139/b81-138

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Protoplasts from will carrot (Daucus carota) cell cultures were fused with protoplasts of the filamentous green algaStigeocloniumsp. using polyethylene glycol. Following fusion of the algal and higher plant plasma membranes, intactStigeocloniumchloroplasts, nuclei, and centrioles were observed within the carrot cytoplasm. Other algal organelles were not distinguishable in the fusion products.

ISSN:0008-4026    

DOI:10.1139/b81-139

出版商:NRC Research Press    

年代:1981

数据来源: NRC