摘要:

This paper is a survey of the ascorbic acid content of native Alberta fruits. Some wild fruits that are not usually eaten have been included in the investigation. The values of vitamin C for the most widely occurring and most generally used wild fruits are: blueberries, 5 to 18 mg.%; chokecherries, 5 to 19 mg.%; high-bush cranberries, 8 to 51 mg.%; pin cherries, 8 to 34 mg.%; raspberries, 14 to 40 mg.%; and saskatoon berries, 5 to 38 mg.%. These afford a considerable source of ascorbic acid.In an addendum there are given the ascorbic acid values in miscellaneous plant materials.

ISSN:1923-4287    

DOI:10.1139/cjr44c-004

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

Significant differences between varieties and hybrid strains ofTriticum vulgarewith respect to the length and frequency of stomata per unit area are established. In studies involving 12 different species and four different chromosome numbers, it is demonstrated that increasing chromosome number is associated with larger and fewer stomata. Both between species and between varieties within species, a negative relation between size and frequency of stomata is demonstrated. Data on stomata were studied in relation to yield of grain under field conditions by means of the correlation coefficient. Significant relations are established and it is concluded that stomatal determinations may be of use in selecting for high yield.

ISSN:1923-4287    

DOI:10.1139/cjr44c-005

出版商:NRC Research Press    

年代:1944

数据来源: NRC

摘要:

A study has been made of various aspects of the biology ofErysiphe graminisDC., including its distribution and prevalence in Canada, method of overwintering, physiologic specialization, and the effects of various environmental factors on the development of different stages of the organism. The fungus causes the powdery mildew of cereals and certain grasses. It occurs in every province of Canada, but is more prevalent in British Columbia and the five eastern provinces. The evidence indicates that the fungus overwinters as mycelial mats on dead straw and as mycelial infections on overwintering hosts. Three new physiologic races of barley mildew have been identified, making a total of seven races isolated in Canada. In wheat mildew only Race 1 was isolated. A study of the stability of six races of barley mildew showed that they are distinct biologic entities comparable to physiologic races in cereal rusts. No evidence was obtained by cross inoculations that any variety ofE.graminis, except possiblyE.graminis Agropyri, can attack a non-suscept, or an immune variety of its host, or that injury of such hosts renders them susceptible. Conidia ofE.graminisgerminate on immune hosts and penetration proceeds as far as the papilla stage. Physiologic resistance manifests itself in some hosts by the death of the infected cells and in others by the distortion of the haustoria. The evidence indicates that the organism is homothallic. The cardinal temperatures for the germination of conidia are 0°, 10°, and 35 °C., while the best development of mildew occurs between 15° and 20 °C. Alternating temperatures induce perithecial development. Light is not an important factor, except indirectly, in the development ofE.graminis. Alternate drying and wetting of perithecia is necessary to induce the formation of ascospores, but other stages are favoured by relatively dry conditions. Conidia germinate well even at zero humidity. Sprinkling infected seedlings with water checked the development of the disease. The addition to the soil of certain fertilizers and other chemicals commonly claimed to increase host resistance to powdery mildew did not increase the resistance of susceptible seedlings of wheat and barley.

ISSN:1923-4287    

DOI:10.1139/cjr44c-006

出版商:NRC Research Press    

年代:1944

数据来源: NRC