摘要:

not available

ISSN:1923-4287    

DOI:10.1139/cjr41c-008

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

The characteristic symptoms of what seems a new disease of potato, observed in Alberta, have been outlined, certain observations and preliminary experiments reported, and the name "purple dwarf" suggested for it.Purple dwarf is perpetuated through the tubers, and the symptoms on plants from diseased tubers either appear immediately the plant emerges from the ground or apparently fail to become recognizable during the remainder of the season.Apical growth is checked, the entire plant becomes stunted, the newer leaves develop a purplish hue along their margins and curl upwards, the phloem of the entire plant is disorganized, and a well developed, brown, dendritic necrosis extends from proximal to distal ends of the tuber. First the roots, then the stolons, and later the base of the stem, become brown and soon decay. Usually the central pith in the tuber and upper stem remains normal.Purple dwarf was transmitted to healthy plants by grafting, a result which suggests that the causal agent is a virus.

ISSN:1923-4287    

DOI:10.1139/cjr41c-009

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

The permanent infection of rust-freeLactuca pulchellaplants byPuccinia minussensismay be initiated by inoculating the primary leaves of seedlings, or the rhizome buds of older plants, with either aeciospores or urediospores, or by packing teliospores into the leaf axils of mature plants and subsequently using the infected nodal portions as propagation cuttings. When a primary leaf of a seedling becomes infected, the binucleate mycelium progresses along the midrib and petiole to the stem and advances down it into the rhizomes but, before reaching the terminal buds of the rhizomes, its nuclear condition changes, as only uninucleate mycelium has been observed in the bud scales. Infected rhizome buds develop into young shoots that usually first produce pycnia, although, in cases of delayed mycelial development, telia appear on the more mature plant followed by pycnia on subsequent new axillary growth. The perennial mycelium seems to alternate from the binucleate to the uninucleate condition and vice versa, depending apparently on the maturity of the host tissue involved and the food supply available to the fungus.

ISSN:1923-4287    

DOI:10.1139/cjr41c-010

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

A previously undescribed feature of the structure of the stem inEquisetumhas been found. This conforms more nearly with a true leaf gap than any other feature ofEquisetumhitherto so considered. Its interpretation and bearing on the classification of the vascular plants into Lycopsida and Pteropsida are discussed.

ISSN:1923-4287    

DOI:10.1139/cjr41c-011

出版商:NRC Research Press    

年代:1941

数据来源: NRC