摘要:

The genusZalerionis reconstituted to includeZ. maritima(Linder) comb. nov. and a new species from salt lakes,Z. varia. Z. nepuraMoore & Meyers,Z. eistlaMoore & Meyers,Z. xylestrixMoore & Meyers,Z. raptorMoore & Meyers, andHelicoma salinumLinder are placed into synonomy withZ. maritima.

ISSN:0008-4026    

DOI:10.1139/b63-093

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Slices of tissue from Jerusalem artichoke tubers were maintained under different growth conditions for periods of between 40 and 60 hours, when they were harvested and the walls isolated. The wall preparations were fractionated into the main polysaccharide components and the contents of uronic acid and sugar residues estimated in these components and in the whole wall preparations. Concentrations of plant hormones, optimal for cell enlargement, caused an increase in the water solubility of the pectic fractions of the walls compared to the situation in the water controls where enlargement was negligible. No differences could be detected in wall composition between ray, pith, and cortex tissue in the tuber. In the presence of plant hormones, tissue enlargement was inhibited by calcium ions for about 30 hours, after which it proceeded at a reduced rate. Such calcium treatment appeared to cause no change in wall deposition or composition. The results are discussed in relation to current ideas concerning the plasticity of primary cell walls.

ISSN:0008-4026    

DOI:10.1139/b63-094

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The addition of ethylenediaminetetraacetic acid (EDTA) at a level of 6 × 10−5 Mto a glucose – yeast extract agar medium inhibits the growth ofHirsutella gigantea. At a concentration of 3 × 10−3 M, the mycelium undergoes a morphological change and yeast-like, single cells are formed. These effects may be attributed to the chelating properties of EDTA since they can be reversed by the addition of the metal ions Mn++, Fe++, or Ca++.

ISSN:0008-4026    

DOI:10.1139/b63-095

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

The gene for broadleaf has been the only gene known to be on chromosome 4 of the tomato. Four other genes are shown to be linked with broadleaf. These are wiry (w1), which distorts the leaves and flowers; clausa (clau), which causes excessive proliferation of the pinnae; divergens (di) which affects plant growth and stem color; and stamenless (sl1), which causes the stamens to be absent or greatly reduced. The genesw1,clau, anddigive mongenic ratios which are deficient in number of mutants. The order of the genes on the basis ofF2data isw1clau39e21di2sl1. The genestf,ao,rv, andahare not in this group.

ISSN:0008-4026    

DOI:10.1139/b63-096

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

A new hyphomycete,Arachnophora fagicola, is described from the cupules ofFagus sylvaticain Belgium, constituting the single species of a new annellosporous form-genus.

ISSN:0008-4026    

DOI:10.1139/b63-097

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Wheat striate mosaic virus from wheat in southeastern Saskatchewan was acquired and transmitted by both nymphs and adults of the leafhopperEndria inimica(Say) collected in Ontario. The preinfective period of leafhoppers varied from 4–6 to 22–24 days after they first fed on diseased plants. Records of serial transmission by individual insects varied greatly. Some insects infected most test plants on which they were given 2-day feeds during 20 to 30 days after the preinfective period, but subsequently they transmitted irregularly. Some transmitted virus for only a few days. Others transmitted intermittently for several weeks. None of the insects infected any plants on which they fed later than 72 days after feeding on diseased plants even though some lived another 10 to 20 days. Two of 25 insects became infective after feeds as short as 30 seconds on diseased plants, but the percentages of infective insects increased to more than 90% as acquisition access times were increased to 2 or more days. All insects from some inbred lines became infective after 3 days on diseased plants, but 45% of the descendants of one non-transmitting female failed to become infective. The inoculation threshold period on Ramsey wheat test plants was 15 minutes, but the percentage of test plants infected increased from 15% to 88.8% as the test access times were increased to 4 days. The incubation period of the virus in Ramsey wheat seedlings varied from 6 to more than 28 days.In tests of host reactions, all durum wheat varieties were highly susceptible to the virus. Several of the hard red spring and winter wheat varieties were highly susceptible and a few others were highly resistant or immune, but most were mildly to moderately susceptible. Most varieties of oats and barley and 10 species of wild annual grasses were moderately susceptible. Mild to moderate symptoms also developed on some of the plants in one or more varieties ofZea maysL.,Lolium multiflorumLam.,L. perenneL., andBromus inermisLeyss. Four varieties of rye tested did not develop symptoms, nor did any plants in 13 species of perennial grasses, includingChloris gayanaKunth, which is susceptible to the Australian wheat striate mosaic virus.E. inimicamultiplied on wheat and 14 other annual and 21 perennial grass species, many of which are common on the prairies. There was considerable variation in the reactions to the virus of different plants in the variety Ramsey, but there were no inherent variations detected between the virus isolates used for the experiments. The wheat varieties Cappelle-Desprez and Rescue which are highly susceptible to the European type of wheat striate mosaic virus did not become infected with the Canadian isolates tested.Attempts to transmit the European type of wheat striate mosaic virus withE. inimicafailed.

ISSN:0008-4026    

DOI:10.1139/b63-098

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Differences of considerable magnitude occur in the tracheid dimensions of North American species ofCupressus. In general the species in arid regions (C. arizonica, C. glabra, C. forbesii, andC. macnabiana) have smaller cells than the species in more humid localities (C. macrocarpaandC. pygmaea). Minor, in some cases questionably significant, differences in cell size are found at different sites for the same species. Noteworthy interspecific differences exist in the frequency of anticlinal (pseudotransverse) divisions involved in cambial cell multiplication. On the whole, these divisions take place at a faster rate in the species with small cells (C. arizonica, C. macnabiana) than in species with large cells (C. pygmaea). Some general relationships between rate of growth, frequency of pseudotransverse divisions, and cell length are also evident. In the stems of mature trees, maximum cell length is apparently associated with a ring width of approximately 1–1.5 mm. Reduction in ring width is accompanied by a rise in frequency of pseudotransverse division and a slight recession in cell length. Widening of the rings produces no change in the rate of anticlinal division, in relation to linear radial accretion, but cell length declines. The orientation of the partition in pseudotransverse division is usually unidirectional in neighboring cells, but reversals in tilt occur after varied intervals. Duration of the interval between reversals shows an inverse relationship with the frequency of pseudotransverse division.

ISSN:0008-4026    

DOI:10.1139/b63-099

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Data on the growth rate of lichens are essential to the understanding of the carrying capacities of rangelands used by caribou and reindeer in Canada. Recent Russian literature suggests fruticose lichens have three growth stages. The first stage is one of podetium accumulation. During the second stage, accumulation rate and decomposition rate are similar, while, in the third stage, decomposition of the Podetium is more rapid than accumulation. In the Taltson River region, the average annual linear growth rates ofCladonia alpestris, Cladonia mitis, andCladonia rangiferinaas determined by dividing the number of joints on the living podetium by the height of the living portion of the podetium, are 3.4, 3.6, and 4.1 mm, respectively. These rates are less than those reported from Russia, Newfoundland, and northern Saskatchewan.

ISSN:0008-4026    

DOI:10.1139/b63-100

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

Ascospore discharge and conidium release ofNectria galligenaBres. from cankers on yellow birch (Betula alleghaniensisBritt.) were investigated under field conditions and were related to prevailing rainfall, relative humidity, and temperature. Release of conidia was associated with splashing rain whereas ascospores were discharged during or after rain. Conidia were trapped only from May through August during the period of active growth of the host, and showed a peak in May and June. In contrast, ascospores were trapped on rainy days throughout the year, including mid-winter when temperatures were around the freezing point. Maximum ascospore discharge occurred in August and September. In the laboratory, ascospores were discharged as wetted perithecia began to dry out. Both relative humidity and temperature affected the rate of perithecial drying and thus the rate of release and duration of discharge of ascospores. The results are discussed with respect to environmental conditions that prevail in eastern Canada during winter.

ISSN:0008-4026    

DOI:10.1139/b63-101

出版商:NRC Research Press    

年代:1963

数据来源: NRC

摘要:

InChenopodium botrys, darkness was suboptimal for germination at all temperatures. At low to intermediate temperatures (10 to 20 °C) short photoperiods were optimal while longer ones were supraoptimal. At high temperatures (25° to 35 °C) extremely long photoperiods were optimal and all shorter ones were suboptimal. There was less germination in light of low than high red to far-red (R/FR) spectral energy ratios, particularly in long photoperiods. Decreasing the R/FR ratio for the terminal 30 minutes of daily photoperiods restricted germination considerably in short but not in extreme long photoperiods (18 and 20 hours). It is postulated that sub- and supra-optimal amounts of phytochrome-Pfrwere produced, respectively, in the sub- and supra-optimal photoperiods, which resulted in less germination; further, that the temperature-induced responses may be due to a lower optimum requirement for Pfrat low than at higher temperatures and, or, a faster rate of dark reversion of Pfrto Prmay occur with increase in temperature. This provides a correlative scheme similar to that postulated for floral initiation ofC. rubrum, whether optimum response is in short or long photoperiods.Ambiphotoperiodism, resembling the response previously shown inC. rubrumfloral initiation, occurred inC. botrysgermination. This may be indicative of endogenously controlled rhythms interacting with the phytochrome system.SeveralChenopodiumspp. germinated more in darkness than in long photoperiods of low R/FR ratio. Indirect evidence suggests that there may be formation of phytochrome-Pfrin darkness, sufficient to promote germination.On the basis of laboratory tests withChenopodiumspp. two ecologically significant phenomena are postulated. Firstly, there may be restriction of germination in areas shaded by green plants. There was more germination in light with R/FR ratios similar to that of sunlight (1.3) than sunlight transmitted through green vegetation (0.70 to 0.12). Secondly, stages of incomplete germination of seeds, in which there is rupture of the testa and loss of previous light requirements, may be of adaptive value, particularly under arid conditions. Seeds with incomplete germination remained viable for prolonged periods, whether kept moist or dried, but germinated very rapidly when transferred to optimum conditions.

ISSN:0008-4026    

DOI:10.1139/b63-102

出版商:NRC Research Press    

年代:1963

数据来源: NRC