摘要:

Dormancy lasted about 6 months in seeds ofZizania aquaticaafterripened at 1–3 °C. Embryos lost dormancy fastest when afterripened under low oxygen tensions. Pricking the water-impermeable seed coat removed some dormancy. Low constant temperatures favored maximum rates of germination, as did alternating high and low, but constant high temperatures decreased rates. Changes in pH between 6.0 and 8.7, and a wide range of concentrations of gibberellic acid had no significant effects on germination. Air-drying of seeds for 90 days caused almost complete loss of viability; a detectable decrease occurred within 14 days. Under certain conditions, freezing caryopses also caused loss of viability. These results are discussed in relation to the habitat of wild rice.

ISSN:0008-4026    

DOI:10.1139/b66-001

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Prepared check lists of specific weeds on abandoned pastures were used to determine the frequency of concurrence of each pair of species. Contingency tables showing the degree of association of the species taken two at a time were used to work out constellation diagrams which showed several allied complexes. Each complex was found to be associated with certain physical site conditions.

ISSN:0008-4026    

DOI:10.1139/b66-002

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The synthesis of α-amylase by excised aleurone tissue can be induced by supplying either gibberellic acid (GA) or a mixture of amino acids and sucrose. Aleurone cells form RNA within 4 hours after the imbibition of water or a solution of GA. Synthesis of RNA is essential for the subsequent production of the enzyme. The primary action of GA leading to production of the enzyme begins at about the same time as the first synthesis of RNA. Loss of dormancy during after-ripening involves changes in the response of aleurone cells to gibberellin. Aleurone cells of a non-dormant domestic oat variety Torch exhibit a greater autonomy in the control of α-amylase synthesis than those of wild oats. The current hypothesis that GA acts by genetic derepression is discussed.

ISSN:0008-4026    

DOI:10.1139/b66-003

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

A survey of dicotyledonous species of the prairie and forest regions of southern Saskatchewan disclosed the occurrence of 38 species (12 introduced, 26 native) which produce adventitious buds on their roots.

ISSN:0008-4026    

DOI:10.1139/b66-004

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The type species ofAscoconidiumSeaver is redescribed and illustrated. Relationship to other phialosporous fungi is discussed.

ISSN:0008-4026    

DOI:10.1139/b66-005

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Stigmina pallida(Ellis & Everhart) M. B. Ellis incited a bark disease of apple characterized by cankers and discoloration of underlying wood of 1- and 2-year-old shoots. It differed in spore size and cultural characteristics fromS. negundinis(Berk. & Curt.) M. B. Ellis, a pathogen of box elder with which it had been considered to be cospecific.S. pallidahad larger spores (36–44–50 × 14–17–20 μ) than those ofS. negundinis(30–36–40 × 11–15–19 μ) and grew in agar culture at a slower rate over a narrower range of temperature.S. pallidawas pathogenic to apple and smooth sumac but not to box elder, whileS. negundiniswas pathogenic to box elder and smooth sumac but not to apple.

ISSN:0008-4026    

DOI:10.1139/b66-006

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

When balsam poplar stem cuttings are grown in a saturated solution of CaSO4(pH 11.0) for 10 days and then transferred to distilled water for another 10 days a resulting callus mass shows two distinct kinds of callus tissue. When the procedure is reversed, the position of the two kinds of callus tissue in a single callus mass is correspondingly reversed. The relationship of each kind of callus tissue to fungal infection and to the development of adventitious roots is briefly discussed.

ISSN:0008-4026    

DOI:10.1139/b66-007

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The amounts of sorbitol (D-glucitol) and related sugars inMalusgrown in daylight and dark were estimated by chromatographic means. Fructose was the largest single soluble carbohydrate fraction in the seed. Sorbitol was found in germinating apple seed, and in all organs of the developing seedling, including the root. Photosynthesizing cotyledons appeared to be a site of synthesis of sorbitol. The results show sorbitol to be a reserve form of carbohydrate in seeds and cotyledons of apple. Sucrose was the major translocate. The oligosaccharides melibiose, raffinose, and stachyose were present in germinating seeds. They seem to serve a storage role in the seed, for they quickly disappeared during germination and did not appear in the actively growing seedling either in light or dark. An unidentified oligosaccharide was present in germinating seeds in appreciable quantity.

ISSN:0008-4026    

DOI:10.1139/b66-008

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

Phenolic extractives were shown to occupy the greatest cross-sectional area in bases of lateral branches ofPinus strobusat or within 1–4 years after needle loss. The cross-sectional area of the extractive-containing wood in lateral branches decreased as the branch weathered. Phenolic extractives were absent from most weevil-killed leaders, but present in nearly one-half of the leaders killed by causes other than weeviling and in bases of all dead suppressed coterminals examined.

ISSN:0008-4026    

DOI:10.1139/b66-009

出版商:NRC Research Press    

年代:1966

数据来源: NRC

摘要:

The cytology and distribution, together with some morphological notes and a key, are given for nine species ofDryopteris(wood ferns) in Ontario. The cytological determinations were made on 239 plants of nine species, considered as five diploid species (x = 41) (D. marginalis, D. fragrans, D. goldiana, D. dilatata, andD. intermedia), three tetraploids (n = 82) (D. spinulosa, D. cristata, andD. filix-mas), and one hexaploid (n = 123) (D. clintoniana).

ISSN:0008-4026    

DOI:10.1139/b66-010

出版商:NRC Research Press    

年代:1966

数据来源: NRC