摘要:

This paper describes and evaluates the results of a scanning electron microscopic study of the sculpture of the surfaces of caryopses, glumes, lemmas, awn columns, and awn subules ofAvena fatua, normal cultivated oats (A. sativa), fatuoids, and F1hybridsA. fatua×sativa. Only qualitative differences were sought, and none were detected in the glumes and on the caryopses. The prickles on the lemmas, on the awn columns, and on the awn subules all appear in two character states. In the case of the lemmas one state is found in the normal cultivated oats, fatuoids, and F1hybrids, and the other inA. fatua. On the other hand in the awn subules one state is found in the normal cultivated oats and the other in fatuoids, F1hybrids, andA. fatua, while in the awn columns one state occurs in cultivated oats and the other inA. fatua, but in the F1hybrids and fatuoids both states occur. These findings provide taxonomic evidence additional to that described earlier based on lodicules coupled with traditional characters.

ISSN:0008-4026    

DOI:10.1139/b71-101

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

In a colorlessChlorellamutant we have found only a very slight enhancement of oxygen uptake in blue light unless FMN is added to the medium. Inhibitor studies and control experiments show that a biological oxidation is involved in the increased oxygen uptake in addition to the well-known photochemical oxidations caused by free FMN. We conclude that FMN is a necessary cofactor in the blue light stimulated oxygen uptake observed in this mutant. Because of its direct role in the process FMN probably also functions as the primary light receptor. The relationship of this enhanced oxygen uptake to the blue light enhancement effects reported by others is considered briefly.

ISSN:0008-4026    

DOI:10.1139/b71-102

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Eighty-nine upland forest stands were selected to cover the ranges of tree species composition, stand ages, understory composition, and site in the area. The role of each tree species as a pioneer, transient, or self-maintaining component of the forest was determined from the number of stems, their vigor, and distribution in tree, sapling, and seedling strata among all stands and from growth increment cores of trees and saplings in 39 stands. Conclusions are drawn regarding the species likely to dominate different sites following severe fire and the kinds of vegetational change likely to occur on them between disturbances. Changing patterns in the non-arboreal vascular flora, moss, and lichen cover were related to changes in tree species composition with site and time. The forest and its environment are linked in an irregular "pulse" strategy of alternating disturbance and regrowth that repeatedly rejuvenates the growing stock.

ISSN:0008-4026    

DOI:10.1139/b71-103

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Early development of the inflorescence of two hybrid clones in the genusSaccharumis presented. Stages of inflorescence development are described for those phases having potential for either further reproductive development or reversion to vegetative growth. The stage of irreversible reproductive growth is ontogenetically much later forSaccharumthan for other plants.

ISSN:0008-4026    

DOI:10.1139/b71-104

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Conjugation was observed in mix-mated pairs of 16Sporobolomyces odorusisolates. The mating tests suggest a simple bipolar mating system. Conjugation resulted in the development of dikaryotic hyphae with clamp connections, and in chlamydospore formation. This dikaryotic phase closely resembled that ofSporidiobolus johnsonii. The chlamydospores germinated by the production of promycelium-like structures or of dikaryotic hyphae.

ISSN:0008-4026    

DOI:10.1139/b71-105

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Indoleacetic acid (IAA) oxidase in tobacco callus tissues (Nicotiana tabacumL., cultivar White Gold) grown on a medium supplemented with gibberellic acid (GA3), IAA, and kinetin was resolved into seven isoenzymes by polyacrylamide gel electrophoresis. Gibberellic acid promoted the development of three fast-migrating IAA oxidase isoenzymes which were 7- to 10-fold more active than those of the control. Gibberellic acid was effective at 2 × 10−9 Mand its activity increased with increasing concentration up to 2 × 10−7 M. Actinomycin D and cycloheximide inhibited the development of these isoenzymes, suggesting a requirement for both RNA and protein synthesis. The GA3-promoted IAA oxidase isoenzymes increased with time and were positively associated with the GA3-induced characteristic type of growth.The expression of the GA3effect on IAA oxidase isoenzymes and growth was dependent on IAA and kinetin. In the presence of appropriate concentrations of kinetin, the combined effect of GA3and IAA was more than additive. A possible interpretation of the GA3–IAA interaction is discussed.

ISSN:0008-4026    

DOI:10.1139/b71-106

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Pistillaria micansFr. andPistillaria setipesGrev. produced fertile sporophores in agar culture. Light was necessary for production of fertile basidiocarps in both species and for pigment production and conidium formation inP. micans. Annelloconidia were produced byP. micans. Viable sclerotia were formed byP. setipes. The taxonomic significance of sclerotia inPistillariaandTyphulais discussed. Neither species demonstrated geotropism, but the fruit body ofP. setipeswas positively phototropic. Temperature optima for growth and sporophore production were ca. 15 °C forP. setipesand ca. 20–22 °C forP. micans.

ISSN:0008-4026    

DOI:10.1139/b71-107

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

High percentages ofP. tomentosusspores germinated on media supplemented with bark extracts from roots of white and black spruce. Best germination was on extracts from the inner bark of black spruce. Spore germination was significantly higher on extracts from root bark of diseased trees than on those from healthy trees.

ISSN:0008-4026    

DOI:10.1139/b71-108

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Continuously feeding a suitable concentration (3 × 10−5or 3 × 10−4 M) of chlorocholine chloride (CCC) through the roots of Kharkov 22 MC winter wheat grown at both hardening (4 to 6 °C) and non-hardening (21°) temperatures induced small increases in its cold hardiness. In plants grown at 21 °C supplying 3 × 10−3 MCCC reduced cold hardiness. Under hardening conditions gibberellins A3and A7and under non-hardening conditions gibberellin A3reduced the cold hardiness of Kharkov 22 MC. CCC produced morphological changes in plants grown at 21 °C that partially duplicated those induced by growing the plants at 6 °C. In plants grown at 6 °C gibberellins A3and A7produced morphological changes that caused the plants to partially resemble those grown at 21 °C. These results are discussed in relation to the hypothesis that one of the changes accompanying cold hardening in winter wheat is a reduction of the content of endogenous gibberellins. The conclusion is reached that if a reduction in gibberellin levels occurs it can only account for a part of the change in cold hardiness produced by natural hardening temperatures.

ISSN:0008-4026    

DOI:10.1139/b71-109

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Claytonia bostockiiPorsild (Portulacaceae), an endemic to S.W. Yukon and adjacent parts of Alaska, whose systematic position in theClaytonia/Montiageneric complex has not hitherto been examined, is shown to possess the distinctive 'Montiastrum-type' of spiniferously saccate pollen. It is suggested thatC. bostockiibe referred, along with the closely relatedC. vassilieviiand the less similarC. linearisandC. dichotoma, toClaytoniaSectionMontiastrumGray. Distinguishing characters are tabulated.

ISSN:0008-4026    

DOI:10.1139/b71-110

出版商:NRC Research Press    

年代:1971

数据来源: NRC