摘要:

Mockernut hickory (Carya tomentosa) trees accumulate the rare-earth elements in foliage in far greater concentrations than do other species on the same site (1350 ppm in ash, compared with less than 60 ppm by red maple, tulip tree, white oak, and black gum). Inoculation of hickory trees with,144Ce showed that this typical rare-earth element moves slowly through woody tissues, with only a small percentage of total-tree cerium lost annually by leaf abscission. Slow decomposition of hickory litter further limits losses of rare earths from the tree–soil system. These processes create centers of rare-earth concentration that perpetuate themselves, exemplifying the role of accumulator species in determining the distribution of elements within ecosystems.

ISSN:0008-4026    

DOI:10.1139/b75-139

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Both the common sugar beet and Indian spinach (locally called Palong) have so far been considered to be the same species,Beta vulgarisL. Critical morphological, karyological, and biochemical studies revealed that Indian spinach is strikingly different fromB. vulgarisand is described here asBeta palongaBasu & Mukherjee sp. nov.

ISSN:0008-4026    

DOI:10.1139/b75-140

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Light and electron microscopy was used to determine the distribution of chloride ions in cells and tissues ofSalicornia pacificaStandl, var.utahensis(Tidestrom) Munz. Chlorenchyma cells with chloroplasts around the periphery and sclereid-like cells with distinct wall thickenings which extended from the anastomosing vascular system to near the epidermis were present in the cortex. The vascular bundles or stelar strands were surrounded by several layers of large parenchyma cells. Tissues were treated with silver acetate for silver chloride precipitation. Silver chloride precipitation sites were present in all cell types. Precipitation sites were readily evident in the vacuoles but not in other organelles.

ISSN:0008-4026    

DOI:10.1139/b75-141

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

On germination, resting spores ofEntomophthora aphidisproduce a septate sporogenous germ tube, which in turn gives rise to two or occasionally three germ conidia, one conidium being formed by the terminal cell and the others from cells lower down the tube. The resting spores possess sufficient endogenous nutrient reserves to complete the germination process.

ISSN:0008-4026    

DOI:10.1139/b75-142

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A survey of the leaf flavonoids of the major taxa ofCassiopeD. Don has been carried out resulting in the identification of eight simple glycosides: myricetin 3-O-glucoside, 3-O-rhamnoside, 3-O-arabinoside (two isomers), and 7-O-glucoside; quercetin 3-O-rhamnoside, 3-O-arabinoside, and 3-O-rhamno-glucoside. Two 5-methoxy derivatives of myricetin have also been identified. The implications of such findings from a phytogeographic and taxonomic standpoint have been commented upon.

ISSN:0008-4026    

DOI:10.1139/b75-143

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Sageria tsugaegen. et sp. nov. (Helotiales) is described from western hemlock (Tsuga heterophylla(Raf.) Sarg.) in British Columbia, Canada. The imperfect state isAscoconidium tsugaeFunk.

ISSN:0008-4026    

DOI:10.1139/b75-144

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The relative contributions of transpiration rate and resistance to water flow in leaves to development of wilt in leaves of chrysanthemum plants (Chrysanthemum morifoliumRamat) infected withVerticillium dahliaeKleb. were examined. Diffusive resistances (inversely related to transpiration rate) of turgid leaves on infected and uninfected plants were similar. When wilt symptoms appeared, diffusive resistance of wilted areas increased (i.e., transpiration rate decreased) while in turgid areas it remained similar to that of turgid leaves on check plants. There was no evidence that transpiration rates changed before development of wilt. In uninoculated plants aqueous solutions of basic fuchsin and14C-mannitol moved freely into turgid leaves and leaves wilted by withholding water. In inoculated plants these tracers moved into turgid areas but not into wilted areas of leaves. Wilted areas closely coincided with areas of restricted tracer movement. These areas first occurred near leaf margins and progressed basipetally to encompass finally the entire lamina. The evidence suggests that wilt ofVerticillium-infected chrysanthemum plants is due to restriction of water movement in vascular elements within the wilted areas of the leaf and that restriction sufficient to cause wilt first occurs near leaf margins.

ISSN:0008-4026    

DOI:10.1139/b75-145

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The history of the genus is reviewed and its taxonomical position is discussed.Lasiobolusis characterized by small, usually yellowish, setose apothecia, non-septate setae, operculate, non-amyloid, eight-spored to multispored asci, and hyaline to yellowish, smooth, unicelled, thin-walled ascospores that contain gas bubbles. Species are distinguished by (1) the number of spores per ascus, (2) the type and arrangement of excipular cells, (3) presence or absence of cyanophilic markings in the setae, and (4) the relative size and shape of asci, spores, and sterile elements.Lasiobolus intermedius, L. microsporus, andL. trichoboloidesare proposed as new species. A key, detailed descriptions, and illustrations are provided for all the 11 recognized species. A list of insufficiently known and excluded species is included.

ISSN:0008-4026    

DOI:10.1139/b75-146

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The effects of various treatments such as herbicide, irrigation, nitrogen, phosphate, and combinations of nitrogen and phosphate on common root rot (Cochliobolus sativus) in naturally infectedTriticum aestivumcultivar ‘Manitou’ were studied at Matador, Saskatchewan, by sampling plants at intervals during 1969, 1970, and 1971. The treatments were compared for each of the following variables : number of diseased plants per square metre, percentages of diseased plants, and percentage disease ratings. Usually, disease assessed by each variable was higher in the checks than in the phosphate treatments. The effect of phosphate appeared maximal at midseason (growth stage 9–10.5). The differences between treatments such as herbicide, nitrogen, and irrigation and the checks were insignificant. A comparison with the results of other workers suggests interaction between phosphate and soil type, and between phosphate and cultivar.

ISSN:0008-4026    

DOI:10.1139/b75-147

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The type species of the genusBroomeaCookson and Eisenack possesses an intercalary archeopyle formed by loss of a single intercalary paraplate. Species with demonstrable apical archeopyles, formerly assigned toBroomea, are excluded by redefinition of that genus and placed inBatioladiniumgen. nov. The taxonomic position of five other species previously assigned toBroomeacannot be resolved on the basis of current information. Transferred to the new genus areBatioladinium jaegeri(Alberti) comb, nov., designated herein as the type species;B. longicornutum(Alberti) comb. nov.;B. micropodum(Eisenack and Cookson) comb. nov.; and provisionally,B.? exiguum(Alberti) comb. nov. andB.? pelliferum(Alberti) comb. nov.

ISSN:0008-4026    

DOI:10.1139/b75-148

出版商:NRC Research Press    

年代:1975

数据来源: NRC