摘要:

The labyrinthulan parasite causing the disease of the Atlantic coastZostera marinaL. is reported onZ.marinafrom Departure Bay, Nanaimo, B.C. The gross and histological appearance of infected Pacific coast eel-grass are described and are found to be similar to those of the Atlantic coast grass and the parasites, in each case, are found to be identical.

ISSN:1923-4287    

DOI:10.1139/cjr38c-008

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

This paper reports the results of an investigation into a condition of the Cuthbert red raspberry which is quite distinct from any previously described disease. The disease, termed yellow blotch-curl, is characterized principally by a loose type of curling and pale chlorotic foliage which sometimes shows a yellow blotching and ring spot. The disease has been transmitted by patch-grafting, which indicates that it is of the virus type. It has been transmitted to Cuthbert, Viking, Latham, Herbert, Chief, and Lloyd George varieties, and different reactions have been noted and described.From these experiments it is concluded that "yellow blotch-curl" is distinct from mosaic and leaf curl.

ISSN:1923-4287    

DOI:10.1139/cjr38c-009

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

The effect of different amounts of phosphorus, potassium, nitrogen, and calcium upon the development of the foot-rot disease of wheat caused byHelminthosporium sativumP. K. & B. was studied in the greenhouse. The wheat grains were planted in sterilized pure quartz sand to which the necessary nutrients and spore suspension of the pathogen were added. The experiments were maintained under aseptic conditions during the first ten days. The disease increased when the ionic concentration of potassium, nitrogen, and calcium was decreased below that of the complete nutrient solution, but no significant reduction of the disease was observed when the concentrations of all of the elements, including phosphorus, were increased above those in the complete nutrient solution. Apparently extremely small concentrations of phosphorus had no effect on the disease one way or the other. These conclusions apply to the disease on the seedling stage of wheat.

ISSN:1923-4287    

DOI:10.1139/cjr38c-010

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

Marquis wheat plants were grown in soil in the greenhouse under uniform conditions until the flowering stage, when six differential treatments,viz., 15, 20 or 25% soil moisture in combination with a diurnal air temperature cycle of 45–70° or 55–80° F., were imposed.The effect of the higher air temperature in increasing nitrogen content through accelerated respiration was evident in grain collected when in the early dough stage (about 50% dry matter). By the late dough stage there were also significant differences attributable to soil moisture under both temperature regimes. However, the nitrogen content of the completely ripe grain was practically the same for all six treatments. This is attributed to a retardation of maturity by both increased soil moisture and lower air temperature, which would permit additional dissipation of carbohydrate through prolonged respiration, and also possibly to differences in the extent of tillering.Compensatory effects of this magnitude would hardly be expected under field conditions, but might occur on a reduced scale, thus increasing the difficulty of correlating nitrogen content with meteorological observations.

ISSN:1923-4287    

DOI:10.1139/cjr38c-011

出版商:NRC Research Press    

年代:1938

数据来源: NRC

摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr38c-012

出版商:NRC Research Press    

年代:1938

数据来源: NRC