摘要:

HyalotiaGuba, type speciesH.laurina(Mont.) Guba (≡Pestalotia laurinaMont.), is reduced to synonymy withBartaliniaTassi.HyalotiellaPapendorf and the type speciesHyalotiella transvalensisPapendorf are redescribed.Hyalotiella orientalissp. nov. is described as the second species of the genus. Some nomenclatural problems associated with the binomialHyalotiopsis subramanianii, representing the monotypic genusHyalotiopsisPunithalingam, are clarified.Hyalotia exilis(Tassi) Guba is redisposed inGampsonemagen. nov. asGampsonema exilis(Tassi) comb. nov. The status of other species ofHyalotiais discussed.

ISSN:0008-4026    

DOI:10.1139/b75-191

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A substance was isolated from dry whole pea seeds (Pisum sativum'Alaska') that inhibited sporulation, but not growth, ofAlternaria alternata,Aspergillus ruber,Ascochyta pisi,Phyllosticta antirrhini,Rhizoctonia solani,Nectria haematococcavar.cucurbitae, andFusarium oxysporumf. sp.pisirace 2. The substance had no effect on sporulation or growth ofAphanomyces euteiches. The mean effective dose (ED50) of the partially purified material was 30 μg/ml when tested againstAlternaria alternata. The partially purified substance was soluble in petroleum ether, chloroform, and hexane but formed an emulsion in water. The partially purified material contained amino acids, lipids, phosphorus, and carbohydrate. Its molecular weight was in excess of 14 000. These properties indicate that it is a complex lipid with properties similar to many proteolipids.

ISSN:0008-4026    

DOI:10.1139/b75-192

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A new species ofOchroconiswith muriform conidia, isolated from tar fragments collected in the Atlantic Ocean, is described.

ISSN:0008-4026    

DOI:10.1139/b75-193

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Leiothecium ellipsoideumSamson and Mouchacca, gen. et sp. nov., is characterized by dark, glabrous ascomata with thin pseudoparenchymatous walls and by ellipsoidal, reticulate, hyaline, one-celled ascospores.Rhexothecium globosumSamson and Mouchacca, gen. et sp. nov., has pseudoparenchymatous initials and is related to the genusEremomycesMalloch and Cain, but it can be distinguished by ascomata with pseudoparenchymatous walls covered with some brown hyphae and by globose, pale yellow ascospores.

ISSN:0008-4026    

DOI:10.1139/b75-194

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Fungi from the litter, fermentation, and humus (LFH) layers of a mature aspen tree stand were qualitatively assessed using the soil-washing method and quantitatively assessed using the agar-film technique. Fungi were isolated and identified at two sampling times, June and October. From the isolation data obtained, it was concluded that the pattern of fungal succession in aspen litter followed the general succession schemes proposed by Garrett (1963) and Hudson (1968). The parasites on living aspen leaves included a sterile dark organism andPleurophomella spermatiospora, while the common primary saprophytes, thought to be existing on sugars and simple carbon compounds in the leaf, includedPenicillium janthinellum,Cladosporiumspp., andAureobasidium pullulans. The secondary saprophytes, such as the cellulose and lignin decomposers and associated fungi, were dominated byPenicillium syriacum,Trichodermaspp.,Mucorspp.,Volutella ciliata, Cylindrocarponspp., andPhomaspp.The quantitative study revealed that the fungal length and biomass per gram dry weight of litter in each layer studied were much higher in October than in June. The amount of fungal mycelium in the humus in each of the two sampling times was not significantly different. The difference in standing crop of mycelium from June to October in the aspen LFH horizon was estimated to be at least 58 g wet mycelium per square metre of dry litter.

ISSN:0008-4026    

DOI:10.1139/b75-195

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Hypocotyl segments of white spruce seedlings, when placed with their basal end in a defined medium containing agar and 6-benzylaminopurine (BAP), formed up to 100 or more scale-like organs per segment. The organs did not arise from a preexisting apical meristem. The induction was inhibited by α-naphthaleneacetic acid (NAA). On medium containing 10−5 M BAP and no NAA, 69% of the explants formed multiple organs. When explants bearing the scale-like organs were transferred to media containing neither BAP nor NAA, the organs grew out into needles, and buds developed. Many of the buds developed into elongated shoots.

ISSN:0008-4026    

DOI:10.1139/b75-196

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The maturation of the primary phloem fibers and secondary xylem fibers inColeusstems was studied using Nomarski optics. The phloem fiber initials differentiate from the procambium at the same time as the earliest sieve-tube elements and companion cells. Lateral expansion and intrusive growth by the fiber primordia, which obliterate most of the other primary phloem cells, continue until the young fibers begin forming secondary walls. The single nucleus divides a few times and cytokinesis occurs by the formation of septa. After a few septa are formed, cytokinesis may not follow additional mitoses. The cell wall continues to thicken, and the septa may develop secondary layers. Although there is some nuclear degeneration, the fibers remain alive after maturity. During their maturation small groups of protophloem fibers in the corner sectors become consolidated into fewer, larger groups by the crushing of intervening cells. The maturation of xylem fibers is more rapid than that of phloem fibers. Secondary wall thickening begins in the second cell from the cambium. After wall thickening ceases, the single fusiform nucleus undergoes mitosis followed by septum formation. The septate wood fiber is alive at maturity.

ISSN:0008-4026    

DOI:10.1139/b75-197

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

Ultrastructural changes within the protophloem fibers and secondary xylem fibers accompany their ontogeny in theColensstem. The plasmalemma of both fibers portrays a gently undulating pattern against the wall before secondary wall formation. Commonly a narrow, hyaline region separates the primary wall and the plasmalemma. Fibrillar material arising from the plasmalemma is condensed in the wall. With the onset of secondary wall formation, undulation of the plasmalemma increases. Many microtubules traverse the membrane and are modified into extracytoplasmic microtubules. Vesicles produced by the dictyosomes and endoplasmic reticulum (ER) pass through or fuse with the plasmalemma. These processes abate after the initiation of the secondary wall. Cisternal, vesicular, and tubular forms of ER, the latter a rare form in wood fibers, fluctuate in amount during ontogeny. Mitochondria increase in number by fission and change in size and cristae volume. Microbodies are common in the youngest phloem fibers but are absent from the xylem initials. Microbodies arising as swellings of ER cisternae are numerous after secondary wall formation is underway in both fibers. Microfilaments are rare in wood fibers but are common in young phloem fibers. Spherosomes, which originate from ER cisternae, disappear during the initiation of the secondary wall. Phloem fiber plastids increase in number by either constriction or concentralization until shortly after the start of secondary wall formation. The plastids of the xylem fibers differ from those of the phloem fibers since the organelles contain phytoferritin and large starch grains initially, divide only by constriction, and do not form membrane-bound bodies.

ISSN:0008-4026    

DOI:10.1139/b75-198

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

A β-1,3-glucan which has characteristics of callose was identified as a component of the cell wall in stomatal guard cells in three species of the fern,Ophioglossum. This identification was made by the fluorochrome properties of callose when stained with aqueous solutions of aniline blue. Controls involved both the effect of solutions of different pH on autofluorescence of guard cell walls and the extraction of leaf tissues with β-1,3-glucanases before staining with aniline blue. An electron-translucent region between the plasmalemma and the cell wall proper was observed with the electron microscope and corresponded in position with the areas that fluoresced after aniline blue staining.Other components of the guard cell wall identified included cellulose, which was identified by staining techniques, polarization microscopy, and electron microscopy; and a phenolic substance identified by a number of staining reactions. The cell wall failed to stain with a number of reagents for the identification of lignin.

ISSN:0008-4026    

DOI:10.1139/b75-199

出版商:NRC Research Press    

年代:1975

数据来源: NRC

摘要:

The epicuticular waxes of glumes of 357 samples, representing all the 27 species of the genusAvena. were examined under the scanning electron microscope. Three basic patterns were discerned, plates, knobs, and filaments, and each sample has been scored for the types found. A fourth category of unstructural pattern has also been scored. Variability within patterns was observed but not scored. It is concluded that epicuticular waxes on glumes inAvenacannot be used for identification of specimens to species except for various special cases when the choice to be made is between two or three alternatives. The main finding is that the degree of variability of the patterns is inversely proportional to the ploidy level. The hexaploid species consist almost exclusively of filaments: the other species have all the three basic patterns, with some species possessing a high proportion of only two patterns.

ISSN:0008-4026    

DOI:10.1139/b75-200

出版商:NRC Research Press    

年代:1975

数据来源: NRC