摘要:

Encoeliopsis laricina(Ettlinger) Groves is shown to be the chief fungus associated with a shoot-blight disease of western larch (Larix occidentalisNutt.) in the Kootenay region of British Columbia, Canada. Symptoms are described and biological characteristics of the fungus are given.

ISSN:0008-4026    

DOI:10.1139/b69-216

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Spores ofHelminthosporium sativumgerminated well at temperatures 30–39 °C while spores ofH. pedicellatumgerminated best at 39 °C with a lower percentage germination at lower or higher temperatures. Although germination of spores of both species occurred in the absence of an exogenous energy source, it was enhanced by various mono- and di-saccharides as well as by various plant extracts such as orange juice. The viability of these spores remained high (above 80%) for over 2 years when stored with a moisture content of 11% at 4 °C. The constituents of spores of both fungi were quite similar with lipids composing about 10% of the dry weight and carbohydrates 5.5–8.3%. Trehalose and mannitol were the most abundant carbohydrates. Spores ofH. sativumhad an endogenous respiration rate that was about 2–3 times greater than that ofH. pedicellatumspores. The respiration rate of spores of both fungi could be stimulated by various energy sources, including sugars and some polyols. The greatest stimulator of respiration was buffered orange juice. As spores aged up to 25 months the respiration rates varied but to no significant extent. Respiration rate of spores of both fungi was not greatly affected by temperature but spores ofH. pedicellatumthat had been incubated for 15 h at either 30° or 39 °C did exhibit a greater oxygen uptake at 39 °C than at 30 °C. Use of various metabolic inhibitors indicated the presence of a functioning oxidative phosphorylation system in spores of both fungi. Lack of response ofH. pedicellatumspores to high concentrations of dinitrophenol and azide may indicate that these inhibitors may have difficulty in penetrating into the cytoplasm.

ISSN:0008-4026    

DOI:10.1139/b69-217

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A method is described for studying carbohydrate exudation from single seeds. The advantages are that the apparatus for collecting exudates is simple, repeated samples may be obtained without removing or damaging the seeds, and exudation from viable seeds can be determined without including nonviable ones. Different seed lots can be compared on a viable seed basis, and in problems on damping-off diseases, this makes any correlations with susceptibility to preemergence fungal infection more valid. Various factors affecting seed exudation can be readily investigated.

ISSN:0008-4026    

DOI:10.1139/b69-218

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The effect of different water depths on wild rice plants (Zizania aquaticaL.) was assessed in terms of morphological and dry weight changes which occurred during a complete life cycle. Specifically, plant heights, number and area of leaves, dry weights of leaf, stem, root, and flower were determined for plants grown under controlled environmental conditions and those under field conditions at Long Point, Lake Erie.Three distinct phases in plant height increase, and associated morphological changes characterized the life cycle of wild rice. While the duration of phases one and three was unaffected by water depth, the time spent in phase two increased with depth and resulted in plants flowering later than those at shallower depths. Sufficient water is required to cover the submersed leaves and to support the floating leaves, while plants at the aerial stage survived with no free water above the rooting media. Yield in terms of dry weight of plant parts is decreased by water depths less than 8 cm and greater than 110 cm. The decline of wild rice in many areas of Ontario is attributed to either excessively low or high water levels during the critical submersed and floating leaf stages.

ISSN:0008-4026    

DOI:10.1139/b69-219

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The various entities included under the nameRhabdocline pseudotsugaeSyd., the fungus causing a needle cast of Douglas fir (Pseudotsuga menziesii(Mirb.) Franco), have been placed into two species primarily on the basis of differences in structure of their ascus apices. The ascospores ofRhabdocline pseudotsugae(which includesR. pseudotsugaesubsp.pseudotsugaeandR. pseudotsugaesubsp.epiphyllasubsp. nov.) are ejected through variously ruptured thin-walled ascus apices, while ascospores ofRhabdocline weiriisp. nov. (which includesR. weiriisubsp.weirii, R. weiriisubsp.oblongasubsp. nov., andR. weiriisubsp.obovatasubsp. nov.) are ejected through distinct annular pores. An emendment to the diagnosis ofRhabdoclinehas been made.R. weiriisubsp.weiriiwas the only entity found to be associated with the imperfect fungusRhabdogloeum pseudotsugaeSyd. The relationship ofRhabdoclineto other members of the Hemiphacidiaceae, the significance of the constancy of the fungus and disease symptoms in Europe, the iodine reaction of asci, and spore maturity are discussed.

ISSN:0008-4026    

DOI:10.1139/b69-220

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Seasonal changes in N, P, K, Ca, Mg, Fe, B, Cu, Zn, Mn, Na, and Al of first- and second-year ovulate strobili and developing seeds ofPinus resinosaAit. were investigated. During the first year, the major macronutrients moved steadily into developing strobili. Nitrogen and P accumulated in high amounts and Ca and Mg in low amounts. Micronutrients also moved into strobili throughout the first year as did Na and Al.The seasonal pattern of uptake and accumulation of nutrients during the second year of strobilus development differed from the first-year pattern. During the period of rapid growth of strobili following fertilization, macro- and micro-nutrients continued to move into cone tissue. However, movement of Mn into strobili stopped abruptly during mid-June when strobili reached maximum size. Beginning in mid-July, N, P, and K began moving out of maturing strobili. Other macro- and micro-nutrients continued to accumulate in strobili during the entire second year.At the same time that mature strobili were beginning to senesce, N, P, K, Mg, Mn, Zn, and Fe rapidly moved into developing seeds. Nitrogen particularly accumulated in high concentrations. Senescing cone tissue appeared to supply much of the N, P, and K that was translocated into seeds. Calcium was present in very low concentrations in seeds whereas Na accumulated in high amounts. Aluminum did not move into seeds after fertilization occurred.

ISSN:0008-4026    

DOI:10.1139/b69-221

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Several factors affecting the stratification process in seeds ofA. saccharumwere investigated. Rates of imbibition and quantitative measurements of flow rate made with an osmometer indicate that the testa offers a severe restriction to water flow and that a significant portion of the stratification period is required for adequate water uptake. Respiration rates showed a close correlation with water uptake by the embryos throughout the stratification period. Whole seed needed 40–60 days to break dormancy; however, removal of the pericarps and tearing of the testas reduced the time needed by as much as two-thirds. Presoaking whole seed at 5 °C had a similar effect. Seeds with their pericarps removed and testas pricked and treated with gibberellic acid or kinetin provided the highest percentage germination and germinated in the shortest time. Additional tests showed that oxygen was not a limiting factor, and an inhibitor present in the pericarp evidently does not play a significant role in the dormancy mechanism. The restricted movement of water through the testa apparently controls and complements the metabolic block in the embryo and accounts for the prolonged stratification requirement.

ISSN:0008-4026    

DOI:10.1139/b69-222

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Much of the spruce occurring in western Montana is suspected of being hybrid derivatives from the introgression betweenPicea glaucaandP. engelmanniiwhose botanical ranges overlap in Montana. These Montana populations were analyzed by chemosystematic methods; resins were collected from typicalP. glauca(Manitoba) and typicalP. engelmannii(Wyoming) populations and these were analyzed by vapor-phase chromatography, as were resins from western Montana populations. Monoterpene compositions were determined and through the calculation of ratios based on the percentages of limonene, myrcene, and beta phellandrene, a two-dimensional ordination was constructed of the typical and hybrid spruce populations. The methods provide a highly useful approach towards interpreting chemosystematic data collected fromPiceapopulations in the northern Rocky Mountains.

ISSN:0008-4026    

DOI:10.1139/b69-223

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The morphological distinctions between the form generaBeaupreaiditesandProteaciditesare discussed. Also the genusBeaupreaiditesis suitably emended to accommodate proteaceous colpoid pollen with coarse reticulate, retipilate, or verrucose sexine. Three species belonging toBeaupreaiditesand three species belonging toProteaciditesare reported from the Edmonton Formation. Two new species are described:Beaupreaidites libitusandProteacidites auratus. The distribution of proteaceous pollen in Upper Cretaceous strata and their paleoecological significance in the Edmonton Formation are discussed.

ISSN:0008-4026    

DOI:10.1139/b69-224

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Root segments of the fernOphioglossum petiolatumwith either an intact root apex or with the apex removed were treated with distilled water (control) or a range of concentrations of kinetin or benzyladenine in aqueous solution. Buds initiated on segments treated with distilled water or low concentrations of cytokinins had an apical meristem consisting of an apical cell with derivatives and a few leaf primordia located immediately beneath an air cavity formed by the lysis of cortical cells of the parent root. There was little cortical proliferation associated with the initiation of these buds. However, application of cytokinins at relatively high concentrations induced considerable proliferation of root tissue and a concomitant organization of numerous apical meristems in this tissue. Each induced meristem was structurally similar to those initiated on control root segments or those treated with low concentrations of cytokinins with the exception that leaf primordia were not as readily visible. Groups of tracheid-like cells were present in the callus-like outgrowths and, in root segments treated with 10.0 mg/l kinetin, large starch-filled parenchyma cells were evident at the periphery of the proliferations.

ISSN:0008-4026    

DOI:10.1139/b69-225

出版商:NRC Research Press    

年代:1969

数据来源: NRC