摘要:

The response of dark respiration to temperature was measured for populations ofLathyrus japonicuscollected from 39–56° N latitude. Carbon loss in dark respiration increases with latitude at all temperatures. This increased respiratory activity is attributable to concomitant increases in both the growth and maintenance components of total dark respiration. The possible adaptive significance of these respiratory responses is discussed.

ISSN:0008-4026    

DOI:10.1139/b80-185

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Basidia ofPisolithus tinctoriusdevelop from terminal hyphal cells. The distal portion of the basidium enlarges, meiosis occurs, and basidiospore initials develop on short, stout, sterigmata, Young basidia and basidiospore initials are embedded in a fibrillar matrix. As spore initials develop, the basidium becomes highly vacuolate as the contents of the basidium move into the spore initials. A single nucleus typically enters each spore initial. A spore initial is eventually delimited from the basidium near the distal end of the sterigma. Wall material is subsequently deposited in this region sealing off the young spore from the basidium. The basidium then collapses leaving the short sterigma attached to the spore. Young basidiospores are initially highly vacuolate but a large lipid droplet eventually develops and displaces the other cellular components to the periphery of the spore. The oldest spores examined possessed a four-layered wall, the outer layer of which bears the surface spines. Many aberrant spores possessing more or less typical surface spines but lacking cellular components were routinely observed in this study side by side with normal spores.

ISSN:0008-4026    

DOI:10.1139/b80-186

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Flower heads ofSonchus arvensisinhabited byTephritis dilaceratabecome swollen and distorted forming a simple prosoplasmic gall. Larval feeding induces the bases of the involucral bracts to expand laterally causing the maturing flower head to become button shaped. The larvae consume tissues of developing florets and receptacle, and prevent the flower head from opening. Host damage byT. dilacerataand the use of gall formers in the biological control of weeds is discussed.

ISSN:0008-4026    

DOI:10.1139/b80-187

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

As little as 200 parts per billion of 2,4-hexadienal in aerial solution stimulated germination ofAlternaria alternataconidiospores in soil-imposed stasis. This compound, as well astrans-2-hexene-1-ol, and palmitic acid, stimulated germination ofFusarium solanif. sp.pisiconidiospores. Other 5- to 10-carbon aldehydes, ketones, and alcohols, as well as some 16- to 18-carbon aldehydes and fatty acids, stimulated germination of these spores at 10- or 100-fold higher concentrations. Chlamydospores ofF. solanif. sp.pisiwere stimulated to germinate by heptanal, octanal, nonanal,trans,trans-2,4-nonadienal, decanal, and undecanal at 20 000 or 20 0000 parts per billion in air, but not by any compound at lower concentrations. Compounds similar to those stimulating germination of conidiospores or chlamydospores inhibited sporulation of vegetativeA. alternatathalli at concentrations as low as 800 parts per billion.

ISSN:0008-4026    

DOI:10.1139/b80-188

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Cytoplasm and walls of developing promycelia and basidiospores ofUstilago maydiswere examined. The promycelial wall was derived from an inner wall layer of the teliospore. Small vesicles and probable Golgi cistemae appeared to be associated with promycelial extension. Some promycelial septa contained small pores; spherical vesicles, formed centripetally in the electron-transparent lamella at the center of the septa, appeared to be involved in promycelial fragmentation. An inner layer of the basidial wall gave rise to the wall of the developing basidiospore, and a collar of torn outer wall material surrounded the spore base. Spores were formed on short sterigmata. No significant vacuolation occurred in the promycelium during initial basidiospore formation, a feature unique among phragmobasidiomycetes examined thus far. The distribution of cytoplasmic organelles in the promycelium is like that seen in vegetative structures of other fungi.The placement of Ustilaginales in the basidiomycetes is supported by the layered walls and small pores in the promycelium. Derivation of the basidiospore wall and the migration of the nucleus into the basidiospore before mitosis resembled aspects of budding in basidiomycetous yeasts.

ISSN:0008-4026    

DOI:10.1139/b80-189

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Mitochondria isolated from Texas male-sterile cytoplasm (T) corn roots and mitochondria within T protoplasts showed similar ultrastructural changes after treatment withHelminthosporium(Bipolaris)maydisrace T (HmT) toxin. These changes included loss of matrix density, disruption of cristae, and swelling. Damage was observed in isolated T mitochondria after 1-min treatments and in mitochondria within T protoplasts after 5-min treatments. At low toxin concentrations or short treatment times, some mitochondria in isolated preparations and in individual protoplasts were altered whereas others were not. With increases in treatment time or toxin concentrations, all mitochondria were damaged. N cytoplasm mitochondria were unaffected by much higher toxin concentrations and longer treatment times. No ultrastructural effects of HmT toxin on other cytoplasmic components were observed, indicating that mitochondria are structurally affected before other cellular sites. The results support the hypothesis that mitochondria are the primary site of HmT toxin damage in living cells.

ISSN:0008-4026    

DOI:10.1139/b80-190

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

A sublethal concentration of 0.25 ppm of atrazine produced many ultrastructural changes on the chloroplasts of mesophyll cells ofLemna minorL., cultivated aseptically in a mineral solution. The number of grana per chloroplast increased, whereas the intralamellar vesicles disappeared and outgrowths formed at the ends of chloroplasts. The grana of treated chloroplasts showed a reduction in the number of lamellae and formed a very dense network. The stroma of the same chloroplasts was reduced and accumulated osmiophilic globules.

ISSN:0008-4026    

DOI:10.1139/b80-191

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Flaviporusis characterized by lignicolous, relatively small and very thin basidiomes, small and broad spores, small pores, dimitic hyphal system, generatives with clamps and agglutinated hyphae. The species occur mostly in the tropics and southern hemisphere butF. browneiextends into Europe where it is restricted to glasshouses and mines. Seven new combinations are proposed:F. hydrophilus(Berk. & Curt.) Ginns,F. liebmanni(Fr.) Ginns,F. minutisporus(Reidet al.) Ginns,F. semisupiniformis(Murr.) Ginns,F. subundatus(Murr.) Ginns,F. vernicifluus(Berk.) Ginns, andRigidoporus cartilagineus(Berk. & Br.) Ginns. A new variety is described:F. liebmannivar.subglobisporusGinns.

ISSN:0008-4026    

DOI:10.1139/b80-192

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Window-leaved plants are succulent plants which possess areas of clear epidermis on their leaves. The underlying water storage tissue is transparent to allow light penetration to the internal chlorenchyma. The most highly evolved window-leaved plants with the most transparent tissue grow completely underground in desert regions. Only the rounded leaf tips are level with the soil surface and directly exposed to incident light. Light transmission curves were measured using live windows of five species of plants from three families (Liliaceae, Piperaceae, Mesembryanthemaceae). These results suggest that subterranean window leaves may be limited to a relatively short effective maximum length because of light absorption by the tissues involved. Scanning electron micrographs (SEM) of these plants show considerable differences in surface structure which may help to modulate incident light. Comparisons with related Mesembryanthemaceae illustrate that a complex series of adaptations have been developed to allow underground growth.

ISSN:0008-4026    

DOI:10.1139/b80-193

出版商:NRC Research Press    

年代:1980

数据来源: NRC

摘要:

Inoculation ofPlatanus occidentalisseedlings withGlomus fasciculatussignificantly increased plant dry weight and foliar phosphorus (P) concentration when compared with the uninoculated control. After 12 weeks inoculated seedlings were 73% taller and 200% greater in total dry weight. The largest dry weight increase was recorded for foliage (212%) followed in order by stem (202%) and root (171%). Averaged overall nutrient treatments, foliar P concentration was 22% greater for the inoculated seedlings. Nutrient regimes representing 1×, 2×, and 4× Hoagland's No. 2 solution and a control significantly influenced seedling height, dry weight, percentage of foliar N, P, and K, and the degree of root colonization. Maximum growth and foliar nutrient concentrations were associated with the 2× Hoagland's nutrient regime followed in order by the 4× and 1× nutrient treatments and the control. Degree of root colonization byG. fasciculatusincreased from 42% of the root length in the unfertilized control to 48% at the 1× Hoagland's regime and sharply declined at the 2× and 4× levels. Total dry weight of inoculated seedlings was significantly greater than the noninoculated control at each nutrient level. Incremental differences were 2.71, 4.03, 4.37, and 3.08 g for the control, 1×, 2×, and 4× Hoagland's nutrient regimes, respectively. Seedling growth attributed toG. fasciculatusis directly related to degree of mycorrhizal colonization and inversely related to the amount of extractable soil P.

ISSN:0008-4026    

DOI:10.1139/b80-194

出版商:NRC Research Press    

年代:1980

数据来源: NRC