摘要:

The effect of maleic hydrazide on leaf rust and stem rust of wheat was investigated, using intact plants supplied with maleic hydrazide through the roots, detached leaves floated on solutions of maleic hydrazide, and spores germinated on maleic hydrazide solutions in agar. In each case the growth of leaf rust was inhibited at concentrations of maleic hydrazide which had no effect on the growth of stem rust. Some resistant wheat varieties became susceptible to rust after treatments with levels of maleic hydrazide which were not inhibitory to rust development. In some experiments, leaf rust races reacted differentially to maleic hydrazide. Both nutritional and inhibitory factors could be involved in resistance and host–pathogen specificity.

ISSN:0008-4026    

DOI:10.1139/b60-001

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

The streak disease of tomatoes in Ontario has been shown to be double-virus in nature, resulting from the synergistic action of tobacco mosaic virus (TMV) and potato virus X (PVX). Expression of the disease was found to be a function of both virus components of the complex, a variation in strain characteristics of either TMV of PVX being reflected in the intensity of their interaction in the tomato.The extreme severity of streak in the greenhouse and field tomato crops in Ontario is associated with what appears to be a geographic strain of TMV. This virus, designated as PLV, is characterized by the induction of primary local lesion in petunia without subsequent systemic invasion of that host.Air temperature profoundly influences the development of streak, symptoms being masked above the critical temperature of 26 °C. This phenomenon is a true masking effect with both viruses becoming latent in the tomato host.

ISSN:0008-4026    

DOI:10.1139/b60-002

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Susceptibility toHelminthosporium sativumin barley coleoptiles is associated with tissue senescence. Aqueous extracts of young coleoptiles show high antifungal activity. This activity disappears rapidly with age owing to the appearance of an inhibitor in the extracts. Preliminary characterization of the antifungal factor suggests an empirical formula of C9H17O7N. Inhibition of activity was found to be caused by various divalent cations. The results point to the particular importance of calcium.

ISSN:0008-4026    

DOI:10.1139/b60-003

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Several current methods for the extraction and estimation of nucleic acids in biological materials were applied toEuglenaand other plants. The efficiency of both the preliminary extractions for acid-soluble-P and lipid-P and the subsequent extraction of the nucleic acids was studied. A relatively high acid concentration (15% TCA) was required to directly extract all the acid-soluble phosphates. These conditions appeared to remove a small amount of the RNA. Lower acid concentrations as used in the Ogur–Rosen method (2% PCA) failed to extract all the acid-soluble phosphates. By using a modification of the Ogur–Rosen initial extraction method, the acid-soluble phosphates were quantitatively extracted without loss of RNA. After removal of the acid-soluble phosphates and lipid phosphates, the plant nucleic acids were quantitatively extracted by either the Schmidt–Thannhauser or Schneider methods. In many of the plants tested, the presence of pentose-containing polysaccharides, protein degradation products, or polyphosphate (algae only) interfered in estimations based on either the Schneider or Schmidt–Thannhauser procedures. Such interfering substances in the Schmidt–Thannhauser method were eliminated by the use of an anion exchange resin. Details are given of a modified Schmidt–Thannhauser procedure which should be suitable for a wide range of plants. The modified procedure may be simplified forEuglenaand some higher plant tissues depending on the nature and quantities of interfering substances present. Methods are also given for the quantitative separation of plant RNA nucleotides by paper chromatography and by ion exchange paper chromatography.

ISSN:0008-4026    

DOI:10.1139/b60-004

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Two naturally occurring races of theFusariumwilt or Panama disease fungus,F. oxysporumf.cubense(E.F.S.) Snyd. and Hans., have been identified. Race 1 is world-wide in distribution and attacks certain AAA triploids ofMusa acuminata, of which variety 'Gros Michel? is the most important, andMusa textilis. Race 2 has been identified in Honduras, El Salvador, Puerto Rico, Virgin Islands, and the Dominican Republic and attacks certain ABB triploids ofM. acuminata×M. balbisianaknown as 'Chato', 'Bluggoe', 'Rulo', or 'Chamaluco'. Both races are pathogenic on 3- to 4-month-old seedlings ofM. balbisiana, M. schizocarpa, andM. acuminatassp.banksii, but the race 2 clone was less pathogenic than the race 1 clones tested. MatureM. balbisianais immune to rhizome infection in the field. 'Odoratum' and 'Inodoratum' cultivars ofF. oxysporumf.cubenseare found within race 1; only the 'Inodoratum' cultivar is found within race 2. Circumstantial evidence indicates an independent development of race 2 in different areas. Race 2 wilt-susceptible ABB triploids hybridize and set seed with pollen from diploidM. balbisiana(BB) andM. acuminata(AA), the two ancestors of the cultivated banana. This will facilitate a study of the inheritance of wilt resistance toF. oxysporumf.cubenseraces 1 and 2.

ISSN:0008-4026    

DOI:10.1139/b60-005

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

The distribution ofElymus macouniiVasey in the Prairie Provinces of Canada is extensive and apparently governed by the occurrence of its putative parents,Agropyron trachycaulum(Link) Malte andHordeum jubatumL. The hybridE. macouniiwas produced by controlled cross-fertilization ofA. trachycaulumandH. jubatum. Subsequently, octoploidE. macouniiwas obtained by colchicine treatment. Cytological studies indicated 2n = 28 forA. trachycaulum, H.jubatum, andE. macounii(both artificially produced and naturally occurring hybrids). Irregular meiosis ofE. macouniiand some irregularity in meiosis of octoploidE. macouniiwere observed.

ISSN:0008-4026    

DOI:10.1139/b60-006

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Three hybrids, two ofHordeum jubatumL. ×Secale cerealeL. var. Prolific, and one ofH. jubatum × H. bulbosumL., were examined cytologically. The two genomes ofH. jubatumshowed autosyndesis in theH. jubatum × S. cerealehybrids. It was concluded, therefore, thatH. jubatumhas two closely related genomes.One of theH. jubatum × S.cerealehybrids displayed weak asynapsis. TheH. jubatum × H. bulbosumhybrid, on the other hand, showed strong asynapsis, although the prophase pairing was almost complete. It was concluded that the asynapsis of this latter hybrid was due to interaction of genes of theH. jubatumand theH. bulbosumgenomes.The chiasma distributions of the hybrids were tested for randomness by Gaul's formula. It was found that the chiasma distributions of theH. jubatum × S. cerealehybrids followed a random pattern, whereas in theH. jubatum × H. bulbosumhybrid the distribution was disturbed by a secondary effect. Cytological observations and theoretical considerations led to the conclusion that the occurrence of pseudo ring-bivalents had disturbed the apparent chiasma distribution in theH. jubatum × H. bulbosumhybrid. A theory of the origin of pseudo bivalents and an evaluation of Gaul's formula is presented.

ISSN:0008-4026    

DOI:10.1139/b60-007

出版商:NRC Research Press    

年代:1960

数据来源: NRC

摘要:

Poria zonataBres., a wood-rotting fungus known only from the western United States and British Columbia, is reported to be widely distributed within that area on recently fallen trees ofAbies grandis, A. concolor, A. lasiocarpa, Larix occidentalis,Pseudotsuga menziesii, andTsuga heterophylla. A description of the sporophores of the fungus, its cultural characteristics, and the white pocket rot caused by it are given.

ISSN:0008-4026    

DOI:10.1139/b60-008

出版商:NRC Research Press    

年代:1960

数据来源: NRC