摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr46c-023

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The inheritance of awn-barbing was studied in crosses of barley varieties having intermediate smooth and very smooth awns and lacking the geneRfor rough awns. Two genes were found to govern awn smoothness in these varieties, one beingShypostatic toRas previously reported and the other, termedS1, hypostatic toS. The genotyperrSSS1S1has intermediate smooth awns,rrssS1S1has smooth awns, andrrsss1s1has very smooth awns.

ISSN:1923-4287    

DOI:10.1139/cjr46c-024

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Storage ofPopulus tremuloidesandP.grandidentataseeds at room temperature in a controlled-humidity series showed the optimum to be 20% relative humidity for both species. At this humidity level, seed viability was retained byP.grandidentatafor 555 days and byP.tremuloidesfor 455 days, as compared to approximately 28 days for both checks (open air).Similar storage of seeds of fourUlmusspecies showed tolerance of a wide humidity range by all species, the optimum storage condition being within a range of approximately 20 to 50% relative humidity.Germinability in all fourUlmusspecies was greatly increased when seeds were tested in a lighted germinator.

ISSN:1923-4287    

DOI:10.1139/cjr46c-025

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Colchicine techniques were developed on the principle that sprouted seeds or seedlings should not be completely immersed in colchicine solutions since the root, an earlier developing, more actively dividing, absorptive organ, will become overtreated before the stem receives sufficient treatment. Sprouting seeds are placed, stem end down, in holes in a corrugated rubber disk fitted into a Petri dish containing colchicine solution. A covering of moist filter papers protects the upturned roots from drying. Seedlings are grown in small pots that are inverted over similar pots containing vials of colchicine solution so that the seedlings in the upper pots are immersed in the vials. In both methods a 0.2% aqueous colchicine solution is used, and immersion ranging from 6 to 48 hr. is required depending on the species.

ISSN:1923-4287    

DOI:10.1139/cjr46c-026

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

The relative merits of different materials as coverings to protect receptive female flowers against chance pollination were studied, and a combination of glassine (inner) and kraft (outer) bags was adopted. Pollination was effected as follows: the kraft bag was removed and the glassine bag punctured with the point of a specially designed pollen gun; the pollen was then driven into the bag by squeezing the bulb of the gun; finally, the puncture was sealed with an adhesive patch and the kraft bag replaced. The pollen gun attaches to pollen containers (small Erlenmeyer flasks) that can be stored over calcium chloride.

ISSN:1923-4287    

DOI:10.1139/cjr46c-027

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Interspecific hybridization in various forest tree genera gave the following results:Populus, 43 crosses;Picea, 12;Pinus, 4;Betula, 14;Fraxinus, 5;Ulmus, 7; andTilia, 9. The hybridity of most of these materials has been proved or strongly indicated by various criteria; but for some of the materials, hybridity is assumed on the basis of seedling production under conditions that largely precluded the possibility of self- or chance-pollination.

ISSN:1923-4287    

DOI:10.1139/cjr46c-028

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

At five years of age, average heights in feet were:Populus alba, 14.0;P.grandidentata, 11.7;F1, 17.6;F2, 9.5. On the basis of anF2population of 168 trees, modes of inheritance were assumed for leaf characters as follows: pubescence, four cumulative factors; colour, 1:2:1 monohybrid ratio; midrib, 42:15:6:1 trihybrid ratio; shape, margin, apex, and base, each inherited on the basis of multiple factors.The high rooting capacity ofP.alba(92%) was transmitted to theF1hybrid as a dominant character. It is suggested thatP.albais homozygous for one or more highly-determining, dominant alleles not possessed byP.grandidentata. Backcrossing failed to increase the degree of rooting. Comparable results fromP.tremuloidesindicated that this species carries an inhibitor for theP.albarooting factor or factors and is deficient for the rooting factor or factors possessed byP.grandidentata.

ISSN:1923-4287    

DOI:10.1139/cjr46c-029

出版商:NRC Research Press    

年代:1946

数据来源: NRC

摘要:

Reduction of the pressure by not more than 200 mm. of mercury, of the air surrounding the conidia ofErysiphe graminis HordeiMarchal, in water-saturated atmosphere at 18 °C., caused an increase in germination percentage when the experimentally treated conidia were compared with conidia allowed to germinate at atmospheric pressure for three hours. At pressure reduction between 200 and 500 mm., germination was only 90% of germination at atmospheric pressure. At pressure reduction more than 500 mm. below atmospheric, germination was impaired although 53% germination was observed at an actual pressure of only 92 mm., and 5 to 6% at 30 to 50 mm. The enhancement of germination under slightly reduced pressure was found to result from an acceleration of the germination process. More conidia in a given sample germinated at reduced pressure within three hours than at atmospheric, but after five hours the germination percentage tended to become equal in the treated and untreated spores. It is suggested that a slight reduction in pressure might allow carbon dioxide to escape more rapidly from the protoplast of a conidium freshly dislodged from its parent conidiophore thus making it possible for germination to proceed more rapidly than in conidia at atmospheric pressure. Increase in pressure was found to depress germinability, but sufficient data were not obtained to determine the exact relationship between pressure increase and germinability. The data recorded offer further confirmation of the previous work by the senior author on the subject.

ISSN:1923-4287    

DOI:10.1139/cjr46c-030

出版商:NRC Research Press    

年代:1946

数据来源: NRC