摘要:

The induction of microbic dissociation of the lactic acid streptococci by the presence in the medium of a carbohydrate with a specific configuration has been studied.Strains ofStreptococcus lactisandStreptococcus cremorishave been shown to undergo dissociative changes when grown in the presence of glucose. Lithium chloride and phenol have been found to be without influence. The change from theS- toR-form was accompanied by loss of lactose-fermenting ability.The cultural, colonial, and biochemical characters of the organisms at different stages of variation have been described.It is suggested that the organism must be in a susceptible condition before dissociation can be induced.

ISSN:1923-4287    

DOI:10.1139/cjr39c-016

出版商:NRC Research Press    

年代:1939

数据来源: NRC

摘要:

Cuttings from the upper and lower regions of a Norway spruce tree were treated with talc only, and with talc containing 1000 p.p.m. indolylacetic acid. Ten weeks after being planted in sand, 43% of the upper and 75% of the lower cuttings were rooted. Hormone treatment increased the number of roots per rooted cutting but decreased the mean length of root. Lower cuttings produced twice the length of root of the upper cuttings, and the mean length of individual roots was also significantly greater. Nineteen weeks after being planted, the cuttings not rooted at 10 weeks were re-inspected, and gave final rooting values for the experiment of 48% for upper cuttings and 86% for lower. Physiological differences are consequently suggested in cuttings taken from the upper and lower regions.

ISSN:1923-4287    

DOI:10.1139/cjr39c-017

出版商:NRC Research Press    

年代:1939

数据来源: NRC

摘要:

Flaxseed from plots seeded at Ottawa and Saskatoon over a period of several weeks and harvested at maturity showed no difference in oil content with dates of seeding, but the iodine values tended to increase with late seeding. Experiments conducted with Bison and Redwing grown in 1936 at Brandon, Saskatoon Edmonton, and Fallis, and with Redwing in 1937 at Brandon, Edmonton, and Fallis, in which the seed was harvested at successive stages of maturity, showed that moisture decreased and dry kernel weight and oil content increased with progressive maturity up to approximately thirty days after flowering. Rate of oil deposition was in some cases extremely rapid, from 80% to 90% of the maximum oil found being deposited by the fifteenth to eighteenth day. Oil content and dry kernel weight reach a maximum several days before visual maturity. Unsaturation proceeds somewhat more slowly and reaches a higher value under climatic conditions favouring slow maturity.

ISSN:1923-4287    

DOI:10.1139/cjr39c-018

出版商:NRC Research Press    

年代:1939

数据来源: NRC

摘要:

Studies have shown thatSeptoria musivaPeck, a North American fungus which occurs commonly as a leaf-spotting parasite on native poplars, produces cankers, in addition to leaf injury, on certain introduced poplars (Populus RasumowskyanaSchneid.,P.PetrowskyanaSchneid., andP.berolinensisDipp.), and the native hybrids, Northwest and Saskatchewan poplar.Field observations and inoculation experiments demonstrated that most of the inoculum for spring infection arises from ascospores of aMycosphaerellastage, and that the fungus enters the stems through mechanical wounds uninjured lenticels, leaf petioles, or stipules. Incipient cankers occur in the bark of the current year's wood, soon girdling leading and side shoots. They later spread from lateral branches into the main stem, developing into perennial cankers which ultimately girdle and kill the trees.

ISSN:1923-4287    

DOI:10.1139/cjr39c-019

出版商:NRC Research Press    

年代:1939

数据来源: NRC