摘要:

InChenopodium rubrumseedlings (ecotypes 50°10′ N and 49°58′ N) betacyanin synthesis is light dependent (completely dark-grown seedlings contain no betacyanin) and is under phytochrome control via both the low energy and the high-energy (HER) reactions of photomorphogenesis. In continuous light, accumulation of betacyanin is linear with time. However, when a single dark period interrupts continuous light, the amount of both betacyanin and chlorophyll synthesized during a given period of time after the dark interruption shows a rhythm reflecting differences in the rate of, and (or) the capacity for, pigment accumulation that are dependent on the duration of the dark period. The rhythm in chlorophyll content was higher in frequency than circadian, with a period of about 15 h, while rhythmicity in the rate of synthesis of betacyanin was circadian. These results suggest that there is endogenous rhythmicity in the metabolic state of the system in darkness. The imposition of light after darkness apparently stabilizes the specific physiological status attained at that respective time of darkness and thus determines the metabolic activity of the seedlings.When glucose was supplied throughout darkness interrupting continuous light, the phasing of the rhythm of betacyanin synthesis was positively correlated with the rhythm of flower initiation, but this was not so when phenylalanine was supplied during darkness. In contrast, when glucose was supplied for a varied length of time in continuous light, there was rhythmicity in the rate of betacyanin accumulation, with a periodicity of about 15 h, that was dependent on the duration of the glucose application.When seedlings were supplied with 10−6 Mgibberellic acid during darkness there was a rhythm in the amount of hypocotyl elongation that depended on the length of a single dark period interrupting continuous light. Other evidence has suggested that there is a rhythm in the stability of the cellular membranes; this rhythm was assayed (non-physiologically) by the time of onset of betacyanin leakage from seedlings into an extraction medium and was apparent only after application of 10−10 Mgibberellic acid. The rhythms in hypocotyl elongation and in membrane stability that were revealed after the application of gibberellic acid suggest that there may be a rhythm in the rate of differentiation and (or) development of the system.It is postulated that endogenous rhythmicity is due to the spatial separation of energy production and use in different cell particulates, with phytochrome acting as a membrane operator.

ISSN:0008-4026    

DOI:10.1139/b70-001

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Both diploid and autotetraploid root tips of rye,Secale cerealevar. Petkus, responded similarly when kinetin and indoleacetic acid (IAA) were added separately to the media in which they were growing. Kinetin retarded the linear growth of the main roots at 1 mg/1 and caused complete inhibition of the initiation of lateral roots; while at 0.1 mg/1, kinetin inhibited the elongation of lateral roots. IAA at 0.1 mg/1 retarded the elongation of main roots, and the initiation and the linear growth of lateral roots. When kinetin and IAA were applied in combination, kinetin was antagonistic to the inhibition caused by a high concentration of IAA in the growth of main roots of tetraploids, but not in the diploid roots.The differential response is considered to be a reflection of their genotypical difference, which may affect the endogenous content or metabolism of these phytohormones of the roots.

ISSN:0008-4026    

DOI:10.1139/b70-002

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The ovules ofStipa tortilisandOryzopsis miliaceaare hemianatropous, bitegmetic, and pseudocrassinucellate (sensu Davis 1966). The hemianatropous shape of the ovule is the result of characteristic patterns of cell division and enlargement in the chalazal area and areas alongside the embryo sac. Embryo sac development in both isPolygonum-type and both have proliferating antipodals. Endosperm is nuclear, although inO. miliaceait is atypical in that nuclear division is synchronous within one portion of the embryo sac, e.g. micropylar, but not synchronous between different portions of the embryo sac, e.g., micropylar and chalazal. Differences in ovule initiation, persistence of the outer integument, fate of the inner integument, nature of the nucellus, shape of the embryo sac, nature of the synergids, cytoplasm of the egg, polar nuclei, and endosperm exist between these two taxa. Both synergids ofO. miliaceaundergo changes before fertilization and one degenerates before fertilization. The pollen tube enters the embryo sac at the base of the persistent synergid. There is presently insufficient embryological data to permit meaningful speculation on relationships betweenStipaandOryzopsis. Embryologically,StipaandOryzopsisare festucoid grasses, as much other evidence indicates. Embryo sac development in the Gramineae is more similar to that of the Restionaceae than to that of the Cyperaceae. This is in contradiction to recent speculations on the relationships of the Gramineae.

ISSN:0008-4026    

DOI:10.1139/b70-003

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Root growth of Mugho pine seedlings was studied in Southern Ontario using a recently constructed rhizotron at the University of Guelph. The investigations have indicated that root growth of this pine in the season following transplanting extends from April to late November. During the summer, average daily root elongation was found to be 6.5 mm in sandy loam and 5.4 mm in organic soils, while during the autumn it was 2.9 and 3.7 mm respectively. Correlations were found to exist between root diameter and rates of root elongation, and suberization. The latter phenomenon began 5 to 7 days after new root growth. In late autumn metacutization occurred. A resinous type of exudate has been observed from the fully suberized roots. Qualitative thin-layer chromatographic studies have shown that the root exudates differed from exudates obtained by wounding pine shoots.

ISSN:0008-4026    

DOI:10.1139/b70-004

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The main anthocyanin pigments of the genusDicentrahave been characterized through the use of spectroscopy and chromatography. This combination of techniques, particularly suited to anthocyanins, has demonstrated that all are glycosides of cyanidin (3,5,7,3′,4′-pentahydroxyflavylium) and that none are acylated. The simplest, found in several species, is cyanidin-3-monoglucoside, while the most complex is cyanidin-3-rhamnoglucosido-7-xyloside. This triglycoside is present in only one species as well as in certain experimental interspecific hybrids, and this is its first reported occurrence in nature. A rapid method is described for identification of anthocyanin sugars using thin-layer chromatography.

ISSN:0008-4026    

DOI:10.1139/b70-005

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Phycomyces blakesleeanussporangiophores attached to mycelium and isolated sporangiophores cultured on plain agar blocks were decapitated at 1–2 mm below the apex (stage 1) or the top of the sporangium (stages 3, 4). One or more sporangiophore initials regenerated at or very near the wound closure after formation of a cross wall. They emerged only from the side on 82–85% of all parents and on most of the rest from the wound closure wall. Lateral initials frequently perforated the original wall. Regeneration on isolated and attached sporangiophores reached 100% at 12 h on stage 1 and 18 h on stage 3, but only 80% after 24 h on stage 4. The frequency of two or more initials per parent decreased from stage 1 to 4 and was greater on attached than on isolated specimens. Fewer than half of all parents with two initials showed maturation of both. Single sporangiophores elongating on isolated stage 1 parents had a larger diameter, greater stage 1 length, and 66% greater final length than on stage 4. Stage 1 was always very short (average maximum, 5.1 mm). Sporangium formation and maturation were most synchronized after regeneration on stage 1 and least on stage 4.Sporangiophores cut at 5 mm above the base regenerated less frequently than after decapitation and the decrease was larger in stage 4 than in stage 1. Hyphae and sporangiophores regenerated alone or together, but hyphae were most common on attached stage 1 stumps. Regeneration was always from the wound closure wall, and two or more sporangiophore initials per parent were less frequent on stumps than near the apex.Observations on outflowing of drops of cell contents and on wound closure are discussed in relation to regeneration.

ISSN:0008-4026    

DOI:10.1139/b70-006

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Pycnidiospores ofBotryodiplodia theobromaePat. germinated within 5 h on solid media. The rate and amount of germination in liquid media were lower than on solid media. Near maximum germination occurred over the range 15–42 °C and at 100% relative humidity. Light, which is essential for pycnidium production, had no effect on germination. Five fungicides (Dinocap (Karathane WD), Pano-drench, Bordeaux mixture, Captan, and copper sulphate) commonly applied to fruits, and four potato sprout suppressants (diethylene glycol monobutyl ether, ethylene glycol monobutyl ether,n-amyl and isoamyl alcohol), at concentrations ranging from 0.001% to 2.5%, inhibited germination and germ-tube growth. The potential use of the germination inhibitors as protectants againstBotryodiplodia theobromaerot is discussed.

ISSN:0008-4026    

DOI:10.1139/b70-007

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Rust mycelia from tissue cultures infected withCronartium ribicolaJ. C. Fisch. ex Rabenh. were grown on cellophane membranes in the absence of physical contact with host tissue. These membranes were in contact with agar media containing imbedded, actively growing western white pine (Pinus monticolaDougl.) tissue cultures. Identities of these cultures were verified by reestablishing infections in healthy host tissue cultures.

ISSN:0008-4026    

DOI:10.1139/b70-008

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Young red pine (Pinus resinosaAit.) trees were grown under three watering treatments from late summer until early fall and under two watering treatments again the next spring. Size of apical buds, date of bud swell and bud burst in the spring, number of needle fascicles on the new shoots, shoot length, and needle-fascicle spacing were related to the first treatments. Most of these plant responses were correlated with bud size, and the correlations were unaffected by the spring watering treatments. The effect of treatments was on magnitude only, i.e. on mean sizes or mean numbers of the plant organs.In all cases in this experiment watering treatments during elongation had no effect on the results. Therefore in a species such as red pine, with determinate height growth, environment during bud formation played an important role in determining later shoot responses by acting on the bud size.Possibly the relationships reported here are genetically characteristic, unalterable by environment or at least by water alone. In this case the effect of environment on the trees was a proportionate increase or decrease in the size or number of plant organs.

ISSN:0008-4026    

DOI:10.1139/b70-009

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

An expanded description ofConiochaeta velutina(Fuckel) Munk is presented. Type studies ofRosellinia velutinaFuckel andRosellinia kellermanniEllis & Everh. show synonymy. Collections and isolations of a fungus previously identified asSordaria minimaSacc. & Speg. are referred toC. velutina. Lignicolous, coprophilous, and terrestrial habits ofC. velutinaare recorded.

ISSN:0008-4026    

DOI:10.1139/b70-010

出版商:NRC Research Press    

年代:1970

数据来源: NRC