摘要:

Fifteen species of wood-inhabiting marine fungi recovered from intertidal wood collected in southern Chile (lat. 43°–55° S), eight Ascomycetes and seven Fungi Imperfecti, are new records for the cold temperate zone of the southern hemisphere. Three of the Ascomycete species were previously reported south of the equator from Australia and one of the Fungi Imperfecti is known from southern Brazil.Monodictys pelagica(Johnson) Jones was the most frequently collected species. The species composition of the Chilean collection is strikingly similar to the species composition of the intertidal lignicolous mycoflora of northern cold temperate waters. A distributional bipolarity is suggested for this group of "cold water" species. A review of lignicolous and algicolous marine fungi reported for the southern hemisphere is included.

ISSN:0008-4026    

DOI:10.1139/b71-001

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

In Douglas fir, scions bearing female strobilus buds were grafted to young seedlings. As the strobili developed, examination was made of the effect of their presence on photosynthesis and photosynthate distribution within the plant. At different times, the conelets constituted between 7% and 21% of the total dry weight of the plants.The presence of conelets did not significantly affect the photosynthetic rate of the leaves. It did, however, significantly alter the proportionate distribution of assimilates by restricting the amount of14C photosynthate available for vegetative growth, particularly that of the roots and the current season's shoots.The conelets themselves had an appreciable rate of photosynthesis as shown by infrared gas analysis, 14-carbon labeling, and autoradiography. Per unit of chlorophyll, conelets were apparently some six times as efficient photosynthetically as leaves; per unit of dry weight, however, they were slightly less efficient than leaves.

ISSN:0008-4026    

DOI:10.1139/b71-002

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Cytoplasmic connections between cells in the aggregation and migration stages of the cellular slime moldDictyostelium discoideumRaper are shown, and some of the implications of such connections are discussed.

ISSN:0008-4026    

DOI:10.1139/b71-003

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Light intensity from 2200 to 43 000 lux during production of urediospores ofPuccinia helianthihad little influence on germinability of fresh spores. The higher light intensities had an adverse effect on germinability of spores stored at −16 °C for 2 months. Daylength had little consistent effect on germinability of fresh or stored spores. Spores produced at day temperatures of 16, 21, and 27 °C showed no effect of temperature on germinability when fresh. After 2 months storage at −16 °C germination was highest for spores produced at 21°. Spores of races 1 and 3 germinated well after 1218 days of storage at −16°, and a small percentage germinated after storage at 4 °C. Races 2 and 4 germinated well after 1136 days storage at −16 and 4 °C. Races 2 and 4 survived longer than races 1 and 3 at 30° and at 23 °C, but not at 13 °C. Race 3 appeared more susceptible than race 1 to effects of light, temperature, and storage.

ISSN:0008-4026    

DOI:10.1139/b71-004

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Budding and fine structure were examined in two compatible haploid strains ofTremella mesenterica. Budding is initiated at one pole; successive buds are developed at the initial site and at any subsequently formed sites. The budding process appears to combine features found in apiculate and non-apiculate ascosporogenous yeasts, and inSporobolomycesandRhodotorula. The fine structure observed suggests that new wall material might be deposited within cells as each successive bud is formed. No differences were observed in either structure or budding of the two mating strains examined.

ISSN:0008-4026    

DOI:10.1139/b71-005

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The genusChaetostictaPetr. & Syd. and its type species,C. perforata(Ell. & Everh.) Petr. & Syd., are redescribed and a lectotype is chosen.

ISSN:0008-4026    

DOI:10.1139/b71-006

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The endodermis, with its associated Casparian strip, is generally believed to act as an effective barrier to the passive movement of ions from the cortex to the xylem in young roots. However, several workers have suggested that the functional integrity of the endodermis might be somewhat impaired with the emergence of branch roots from the pericycle, thus providing pathways for the mass flow of water and ions into the stele. The present work was undertaken to examine the validity of this hypothesis.Sections of lateral roots embedded in glycol methacrylate were stained and examined by fluorescence microscopy, and a general picture of the relationship between branch root development and concomitant changes in the endodermis emerged. The endodermal cells of the parent root were found to maintain a continuous, unbroken, suberized layer over the surface of a very young lateral root, but with continued elongation there is a period when formation of the Casparian strip lags behind division of endodermal cells. It appears likely that, at this stage, water and ions can enter the stele of the parent root by mass flow.

ISSN:0008-4026    

DOI:10.1139/b71-007

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

The ascogenous hyphae and asci ofPlatyspora pentamera(Karst.) Wehm. arise from the lower cells of the pseudoparaphyses at the bottom of the ascocarp centrum. Ascospore development, showing the sequence of septation, is described and illustrated.

ISSN:0008-4026    

DOI:10.1139/b71-008

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Cabbage root hairs provide a useful system for studying responses to infection byPlasmodiophora brassicaeat the cellular level. Roots of cabbage seedlings grown in liquid culture were inoculated with zoospores ofP. brassicae, and the effects of infection on host nucleolar development and root hair cell extension were studied. Within 18 h after the root hairs emerged from the trichoblasts the nucleoli of noninfected cells declined in diameter from 5 μ to less than 1 μ. Root hairs which became infected, whether 6 h old or 24 hold, had a nucleolar diameter ranging between 1.5 and 3 μ. The diameter of the nucleolus did not increase above 1.5–3 μ regardless of the age and number of Plasmodia within the cell. In addition to nucleolar enlargement, parasitized cells became stunted and often enlarged at their tips. Growth of Plasmodia within hair cells occurred with synchronous division of their nuclei. After penetration by the parasite there was an 18 h lag before the first nuclear division within the Plasmodia after which synchronous nuclear division occurred at about 4-h intervals.

ISSN:0008-4026    

DOI:10.1139/b71-009

出版商:NRC Research Press    

年代:1971

数据来源: NRC

摘要:

Reciprocal crosses were performed with barley (Hordeum vulgareL. cv. ‘Gateway’) and a virescens mutant derived from it. The results from F1and F2generations of the crosses showed that chlorophyll deficiency was governed by a single recessive gene. Quantitative analysis of pigment concentrations in normal and mutant shoots of F1and F2plants of the same age provided evidence for heterosis in chlorophyllasynthesis.

ISSN:0008-4026    

DOI:10.1139/b71-010

出版商:NRC Research Press    

年代:1971

数据来源: NRC