bluuebunny/crossref_metadata_2025 huggingface dataset:
THE CYTOLOGY OF INFECTION STRUCTURE DEVELOPMENT IN UREDIOSPORE GERM TUBES OF UROMYCES PHASEOLI VAR. TYPICA (PERS.) WINT.
Authors: Maheshwari Ramesh , Hildebrandt A. C. , Allen P. J.
Published: August 2008

Urediospores of Uromyces phaseoli var. typica (Pers.) Wint. race 32 Arth. germinated on mineral oil – nitrocellulose membranes and sequentially developed appressoria, vesicles, and infection hyphae. The nuclear behavior during in vitro differentiation of infection structures was studied by use of the Feulgen technique. The two urediospore nuclei divided in the germ tube before the formation of appressorium. This was followed by a second division of the four daughter nuclei in the appressorium, and occasionally by a third division of the eight nuclei in the vesicle and infection hypha. Haustorial mother cells were formed in infection hyphae in vitro and contained from two to five nuclei. In contrast, nuclear division did not occur in germ tubes where growth continued linearly. Infection structures that developed in vitro resembled those produced during infection of the host by urediospores of other species of rust fungi.
THERMAL STABILITY OF STEM RUST RESISTANCE IN OAT SEEDLINGS
Authors: Martens J. W. , McKenzie R. I. H. , Green G. J.
Published: August 2008

Six of the identified genes for stem rust (Puccinia graminis Pers. f. sp. avenae Erikss. and Henn.) resistance in oats (Avena sativa L.) are divided into three categories of thermal sensitivity: resistance conferred by genes A and D is stable; that conferred by genes H and F 'breaks down' at intermediate temperatures; and that conferred by genes B and E breaks down at relatively low temperatures. Studies of oat lines carrying single or several resistance genes indicate that thermal sensitivity of the reactions conditioned by the genes conferring labile resistance is not affected by the presence of genes conferring stable resistance or by the rest of the host plant genotype. The critical temperature of breakdown varies with physiologic race.
FAT METABOLISM IN HIGHER PLANTS. XXXIII: DEVELOPMENT OF FATTY ACID SYNTHETASE DURING THE "AGING" OF STORAGE TISSUE SLICES
Authors: Willemot Claude , Stumpf P. K.
Published: August 2008

Parallel to the changes which have been described in the metabolism of dormant storage tissue during "aging", a several-fold increase in fatty acid synthetase activity and a change in the pattern of fatty acid synthesis was observed in aging potato disks. These changes occur very early in the aging process. Their significance is discussed.
MEDITERRANEAN AND ASIAN TAXA OF ANEMONE (SECTION ERIOCEPHALUS) WITH TUBEROUS ROOTSTOCKS
Authors: Madahar Cecily
Published: August 2008

Old World species of Anemone L. (section Eriocephalus Hook. f. & Thoms.) with tuberous rootstocks have been classified into three groups on the basis of their distribution and karyotypes. Anemone coronaria L., A. pavonina Lam., and A. hortensis L. of the northern, central, and eastern Mediterranean regions have karyotypes characteristic of the genus: three acrocentric, one submetacentric, and four metacentric chromosomes. Chromosomes of A. coronaria are smaller than those of A. pavonina and A. hortensis. Anemone palmata L. from the western Mediterranean differs from these in having four acrocentric and four metacentric chromosomes. Karyotypes of taxa from central Asia received as A. "bucharica", A. "petiolulosa", and A. "biflora" have three acrocentrics, two submetacentrics, and only three metacentrics. All taxa are diploid, 2n = 16, except A. palmata in which tetraploid populations are also known.Crosses between Old and New World species of Anemone with tuberous rootstocks were failures while those between Old World species with tuberous rootstocks and New World species with fibrous or woody rootstocks met with limited success.
ON THE RELATIONSHIP BETWEEN MATURE STRUCTURE AND ONTOGENY IN THE GRANA OF CHLOROPLASTS
Authors: Paolillo Jr. Dominick J. , Reighard Judith A.
Published: August 2008

Some reports on chloroplast infrastructure have emphasized a helical pattern of interconnections among the compartments of the grana. This pattern has been related to a theory of spiral–cyclical growth of grana stacks. The occurrence of multiple helices on the grana in angiosperm chloroplasts impugns the ontogenetic significance of the helical pattern. The compartments of a granum do not discriminate among the helices for quantity or quality of interconnections. No genetic helix can be distinguished. The theory of spiral–cyclical growth of grana, as currently stated, is inadequate to account for the in situ structure of normal grana in the chloroplasts of angiosperms.
THE INHIBITION OF BRUSSELS SPROUT LEAF SENESCENCE BY KININS
Authors: Dennis D. T. , Stubbs M. , Coultate T. P.
Published: August 2008

The senescence of leaf discs cut from mature Brussels sprout leaves is retarded by a number of kinins. Other plant growth regulators are without effect. When young expanding leaves are treated with kinins the senescence processes appear to be accelerated. The effect of N-6-benzyladenine on the structure of the cell organelles in young and old leaves has been studied by electron microscopy. It has been found that in mature leaves the chloroplast is the organelle which senesces first and the breakdown is retarded by N-6-benzyladenine. The mitochondria are very stable. In young leaves N-6-benzyladenine appears to over-stimulate the chloroplast, causing enlargement and excessive membrane synthesis.
EVOLUTION AND RELATIONSHIPS OF NORTH AMERICAN PEDICULARIS RUSTS AND THEIR HOSTS
Authors: Savile D. B. O.
Published: August 2008

The nearctic rusts of Pedicularis are not closely related to Puccinia lapponica and P. pedicularis of Europe. P. rufescens of the southern Cordillera consists of 2 newly recognized varieties: var. rufescens on Ped. canadensis, centranthera and semibarbata; and var. densiflorae on Ped. densiflora. P. helicalis is confined to Ped. capitata in the arctic and subarctic. P. clintonii is newly divided into 7 morphologically distinct varieties: var. clintonii on Ped. canadensis and fluviatilis; var. racemosae on Ped. racemosa ssp. racemosa; var. albae on Ped. racemosa ssp. alba; var. bracteosae on Ped. bracteosa and paysoniana; var. ornithorhynchae on Ped. ornithorhyncha; var. groenlandicae on Ped. groenlandica; and var. sylvaticae on Ped. sylvatica in Scotland. Lack of resting spores makes definite assignment of rusts on Ped. palustris in Ireland and Ped. resupinata in Japan impossible. The ramification of P. clintonii and P. rufescens across temperate North American hosts and failure to attack the largely holarctic northern species suggest that many temperate North American species of Pedicularis are derived from a single Asiatic immigrant.
PARASITISM IN PHOLISMA (LENNOACEAE): II. ANATOMICAL ASPECTS
Authors: Kuijt Job
Published: August 2008

The anatomy of roots and haustoria of Pholisma depressum is detailed. Lignified xylem consists of vessel elements only, and is associated with some xylem parenchyma. Sieve tube members exist in both the stem and the root. The pilot root is characterized by a restriction of cambial activity to the primary phloem regions, thus resulting in 3–5 bundle-like structures in older roots. From the protoxylem points between these bundles vascular flanges extend radially outward. The steles of lateral roots are extensions of these vascular flanges. A root cap is recognizable but very thin.The endophyte is a lobed organ with sinuous and irregular vascular strands lacking any phloem-like tissues. Strands, occasionally uniseriate, invade adjacent host tissues, usually in phloem-producing regions of the host cambium. These strands establish xylem-to-xylem contact, but are parallel to host xylem elements. They may subsequently become partially encapsuled by the latter. No radial sinkers exist.The nuclei of the endophyte show a more or less permanent type of heteropycnosis, the significance of which is unknown.A comparison of the parasitism of Lennoaceae and Orobanchaceae yields a number of significant differences in the structure and development of roots and haustoria.
CULTURAL STUDIES OF SEXUAL REPRODUCTION OF CERATOCYSTIS FAGACEARUM
Authors: Bell W. R. , Fergus C. L.
Published: August 2008

The optimum KH2PO4 concentration for perithecium production by Ceratocystis fagacearum in a semi-synthetic agar medium was 7.4 × 10−1 M. A great reduction in the number of perithecia occurred at 0.1 M and none were formed at 0.2 M concentration. The optimum pH was 5.2 and no perithecia formed at pH 7.0. Either exogenous thiamine or its pyrimidine moiety is absolutely essential for perithecium formation. Pyridoxine, inositol and biotin were not required for growth or reproduction. Receptivity of 14-day-old cultures remained high for longer periods when stored at 12 °C than at 3 °C or 21 °C. Of the 17 isolates studied, 14 produced sterile perithecia before conidia were applied experimentally. Attempts to fertilize these were unsuccessful. Perithecia which did not extrude ascospores formed on colonies following application of conidia. In such perithecia, opened ostiolar hyphae did not necessarily indicate sterility. Neither abrasion of colonies, nor brushing with sterile distilled water or with a filtrate of sonic-disrupted condia, increased sterile perithecium production. However, brushing the colonies with an extract of germinated conidia did increase their formation.
EVOLUTIONARY RELATIONSHIPS OF THE SOUTHERN FLORIDA POPULATIONS OF LINUM RIGIDUM (LINACEAE)
Authors: Mosquin Theodore , Hayley Dianne E.
Published: August 2008

Several tetraploid (n = 30) Linum rigidum varieties from Florida were crossed with numerous diploid (n = 15) species of Linum from the Great Plains. The hybrids were studied for meiosis, fertility and for other features. Conclusions are drawn about evolutionary relationships.
AN ELECTRON MICROSCOPE STUDY OF INTRAVACUOLAR BODIES IN THE UREDIA OF WHEAT STEM RUST AND IN HYPHAE OF OTHER FUNGI
Authors: Thomas P. L. , Isaac P. K.
Published: August 2008

An electron microscope study of plant and fungal specimens fixed in a mixture of glutaraldehyde and acrolein followed by osmium tetroxide showed intravacuolar bodies with an intricate internal structure ranging from myelin-like membranes to a system of tubules. The bodies were commonly found in the developing uredia of stem rust infected wheat leaves and in the hyphae of several species of fungi. The origin and nature of the bodies is discussed.
THE LEAF SCORCH DISEASE OF STRAWBERRY (DIPLOCARPON EARLIANA) AND THE NATURE OF RESISTANCE TO IT
Authors: Dhanvantari B. N.
Published: August 2008

Conidial germination required free water, was independent of an external supply of nutrients, and was not influenced by water leachates of resistant or susceptible strawberry leaves. Twenty and 25 °C were optimal for conidial germination, growth and sporulation in vitro and for infection. Chlorogenic acid was demonstrated in strawberry leaves and inhibited conidial germination at 100 p.p.m., retarded growth and sporulation at 1000 p.p.m. and inhibited them at 2000 p.p.m.Thiamine was found to be essential for in vitro growth and sporulation. Sodium nitrate and ammonium sulphate were poorly utilized as compared with casein hydrolysate. Among the amino compounds and sugars found in strawberry leaves, aspartic acid, asparagine, glutamic acid, glutamine, γ-aminobutyric acid, glucose, and sucrose promoted growth or sporulation; serine, alanine, and fructose were less suitable, while threonine and xylose did not support any growth.The young leaves of a selected number of strawberry varieties, considered to be resistant or susceptible to Diplocarpon earliana in the field, were all highly resistant in the greenhouse to isolates of D. earliana used; in contrast, mature leaves of all but Catskill were susceptible.In two sets of experiments, analyses of strawberry leaves for free amino compounds and sugars showed detectable amounts of aspartic, glutamic, and γ-aminobutyric acids, serine, asparagine, glutamine, threonine, alanine, glucose, fructose, sucrose, and xylose. Generally the highly resistant young leaves were lower in aspartic and glutamic acids, glucose, and sucrose. Mature leaves of the resistant Catskill were generally characterized by lower levels of one or more of aspartic, glutamic, and γ-aminobutyric acids, glucose, and sucrose than those of susceptible varieties.In the growth chambers, a short time before the appearance of symptoms, infected mature leaves of the susceptible Jerseybelle and Pocahontas had more γ-aminobutyric acid, glucose, or sucrose than those of the resistant Catskill. In the greenhouse during summer, mature leaves of the susceptible Sparkle in an advanced stage of infection had a great deal more glutamic and γ-aminobutyric acids, glutamine, alanine, glucose, fructose, and sucrose than comparable leaves of Catskill.
AUTORADIOGRAPHIC STUDY OF THE PATHWAY OF TRANSLOCATION
Authors: Trip P. , Gorham P. R.
Published: August 2008

Autoradiography was used to determine the tissues and cells involved in the downward translocation of 14C and tritium labelled photosynthate. Improvements were made in existing autoradiographic techniques to minimize movement of water-soluble substances and to obtain high resolution. In the autoradiographs, patches of silver grains were located in the region of the phloem of stem and petiole veins. In squash, these patches were mainly confined to the area occupied by the sieve tube. It is concluded that longitudinal translocation occurs in sieve tubes rather than in other phloem cells.
EARLY FLORAL DEVELOPMENT OF LYTHRUM SALICARIA
Authors: Cheung M. , Sattler R.
Published: August 2008

The primordia of the six whorls of floral organs are initiated in the following sequence: (1), inner sepals; (2), outer sepals; (3), outer stamens; (4), gynoecium; (5), inner stamens; and (6), petals. This sequence of initiation has not been reported thus far for any species of vascular plants. Its relevance to present theories of the "flower" and floral apices is discussed. The inflorescence and floral apices have a tunica-corpus organization. The tunica is biseriate or uniseriate depending on the stage of development. Bracts, sepals, petals, stamens, and pistil wall originate from periclinal divisions in the T2layer. In contrast, the floral apices originate from periclinal divisions in the outer corpus layer and the T2layer. Procambial development is acropetal. Soon after the procambial cells are clearly discernible they seem to form a cylinder which at one level gives off 12 strands to the two whorls of sepals. At a higher level the procambial cylinder gives off four procambial strands which enter the pistil wall. The procambial strands of the stamens and petals are attached to the strands of the inner and outer sepals. The histogenetic results including procambial development are discussed in relation to some general principles of histogenesis and procambial formation.
CYATHUS AFRICANUS, A PREVIOUSLY UNDESCRIBED BIRD'S NEST FUNGUS
Authors: Brodie Harold J.
Published: August 2008

A sepia-colored saccate Cyathus from 8000 ft on Mount Kilimanjaro is named and described. The leading features of the fungus are: the curly tomentum, the pale, conspicuous basal emplacement, the saccate non-plicate peridia, and the apiculate basidiospores. C. africanus appears to be related to the widely-distributed C. olla (Batsch) ex Pers. and to C. earlei Lloyd.
NECTAR SECRETION IN EXCISED FLOWERS: IV. SELECTIVE TRANSPORT OF SUCROSE IN THE PRESENCE OF OTHER SOLUTES
Authors: Shuel R. W.
Published: August 2008

Various structurally diverse compounds appear in the nectar of excised flowers of snapdragon (Antirrhinum majus) when added to the culture solution. Quantitative analyses of individual nectar constituents were made to obtain information on the interrelations of movement of sucrose, which is the major solute in snapdragon nectar, other solutes that normally are present only in very small amounts or absent, and water. Nectar yields were altered experimentally either by changing the concentration of sucrose in the culture solution or by adding indoleacetic acid (IAA) to it. A representative of each of three different groups of compounds was tested in combination with sucrose. There was a common pattern of variation in yield, differing from that of sucrose, for sodium chloride, urea, and xylose. Sucrose promoted nectar flow and its yield in nectar was depressed by IAA, whereas the other solutes did not promote nectar flow and their yields were insensitive to IAA. Nectar concentrations of the other solutes were not affected by the concentration of sucrose in the culture solution, but their yields were increased proportionately to the sucrose-induced increase in nectar volume. The results are interpreted as indicating a selective transport of sucrose, an indirect influence of sucrose on yield of other solutes through its effect on water movement, and independence of water and solute movement at some stage in the production of nectar in excised snapdragon flowers.
ASEXUAL REPRODUCTION AND BEHAVIOR OF ZOOSPORES OF PHYTOPHTHORA MEGASPERMA VAR. SOJAE
Authors: Ho H. H. , Hickman C. J.
Published: August 2008

A method was devised to produce abundant zoospores in distilled water suspension from pure cultures of Phytophthora megasperma var. sojae. Sporangia were predominantly non-papillate, but occasionally inconspicuously or conspicuously papillate, germinating with the formation of a delicate, evanescent vesicle. Proliferation of sporangia was observed.Flagella action of freely swimming zoospores was investigated photographically. Both flagella were proved to undulate. Zoospores remained motile longest at 15 °C. Motility was markedly reduced at extreme temperatures (5 and 36 °C), at extreme pH values (below 5.2 or above 9.25), or by mechanical disturbance, dilution, and frequent contact with solid surfaces. The fate of flagella during encystment was followed. Encysted zoospores germinated by germ tubes, or by secondary zoospores, or in rare cases, the germ tube was terminated by a miniature sporangium. Repeated emergence of zoospores was favored at 15 °C whereas total cyst germination and germ tube production was best at 25 °C and in the presence of nutrients.
THE INFLUENCE OF FERTILIZATION WITH KNO3 ON SOME NITROGEN FRACTIONS IN TOMATO PLANTS
Authors: Ward Gordon M. , Hawkins Dawna E.
Published: August 2008

Tomato seedlings grown in soil at a low level of nitrogen nutrition were fertilized with KNO3 at two rates of application and the progress of subsequent foliar nitrogen conversion was followed at intervals over a 48-h period. Total nitrogen and nitrate nitrogen increased rapidly and markedly. The quantities of 14 free amino acids were found to change in a pattern which was influenced by the normal diurnal patterns of change. Some acids increased in concentration by more than 20 times and the total free amino acid concentration increased by 7 times. Fertilizer nitrogen applied late in the day followed a different pattern of conversion from that applied early in the morning. Of the 14 amino acids measured, aspartic acid, serine, glutamic acid, and alanine accounted for 83–90% of the total concentration.
METABOLISM OF AROMATIC COMPOUNDS IN HEALTHY AND RUST-INFECTED PRIMARY LEAVES OF WHEAT: II. STUDIES WITH L-PHENYLALANINE-U-14C, L-TYROSINE-U-14C, AND FERULATE-U-14C
Authors: Fuchs A. , Rohringer R. , Samborski D. J.
Published: August 2008

Wheat leaves infected with stem rust, especially those of susceptible plants, contained more phenylalanine and tyrosine than healthy leaves. The utilization of phenylalanine was increased in both the susceptible and resistant reaction, but the utilization of tyrosine was increased only in the susceptible reaction. No evidence of interconversion of these amino acids was obtained.In n-butanol extracts, which contained glycosides, many constituents were labelled after feeding of L-phenylalanine-U-14C. Most of the n-butanol extractives from resistant-reacting leaves contained more label than those from susceptible-reacting leaves or from healthy leaves. However, one of the n-butanol extractives from susceptible-reacting leaves was 5–10 times as active as that isolated from the other tissues.With L-phenylalanine-U-14C and ferulate-U-14C as precursors, more activity was recovered in insoluble than in soluble esters (of ferulate and p-coumarate). With L-tyrosine-U-14C as precursor, the reverse was observed. After infection, the proportion of label in insoluble esters increased more in resistant leaves than it did in susceptible leaves, regardless of the precursor used.A major portion of the activity from these precursors was recovered in the insoluble residue that contained protein and other polymers. In the experiment with L-phenylalanine-U-14C, this residue was fractionated into protein and non-hydrolyzable material. Susceptible-reacting leaves contained equal amounts of activity in these fractions, while resistant-reacting leaves incorporated 2.5 times as much activity into the non-hydrolyzable material as into protein.
FACTORS AFFECTING VIRULENCE AND PIGMENT PRODUCTION OF XANTHOMONAS PHASEOLI VAR. FUSCANS
Authors: Basu P. K. , Wallen V. R.
Published: August 2008

Isolates of Xanthomonas phaseoli var. fuscans (Burkh.) Starr & Burkh. obtained from naturally infected bean (Phaseolus vulgaris L.) seeds stored at 10 C for 2–4 months were more virulent, as indicated by a stunting effect on Sanilac bean plants, than isolates obtained from seeds stored for 7–24 months. Neither the rate of growth of the organism nor its ability to produce a brown diffusible pigment was correlated with virulence. Growth rate and pigment production of all isolates in nutrient broth were similar and reached a maximum after 36 and 48 h respectively. In a medium containing inorganic salts and yeast extract, the growth rate of the organism was relatively slow and pigment development depended upon amendments added to the medium. Tyrosine enhanced, while glucose retarded, pigment production, but neither affected the growth of the pathogen adversely. The formation and color of the pigment in the media were not affected by pH values ranging from 5.5 to 9.0. The presence of living cells was essential for the continued production of the pigment. The melanoid nature of the pigment was demonstrated.
TOMATO BUSHY STUNT VIRUS FROM PRUNUS AVIUM L.: I. FIELD STUDIES AND VIRUS CHARACTERIZATION
Authors: Allen Wayne R. , Davidson T. R.
Published: August 2008

Tomato bushy stunt virus was isolated apparently for the first time from naturally infected rosaceous plants. The virus was recovered from leaves, flower parts, seeds, and fruit flesh of sweet cherry trees growing in Ontario. Characteristic symptoms associated with the presence of the virus were pitted fruit flesh, veinal necrosis, leaf twisting, and severe shoot stunt. Orchard spread was not proved and the virus was not recovered from the soil or from orchard weeds. Results from tests on transmission by pollen and by Olpidium zoospores were also negative. The cherry isolate was distinguishable from the type strain in Datura and tomato. Both viruses appeared to have the same particle size and morphology, but differed slightly in their rates of sedimentation and in antigenic composition.
Respiratory activity of fungal associations in zones of heart rot and stain in sugar maple
Authors: Good H. M. , Basham J. T. , Kadzielawa S. D.
Published: August 2008

Some of the progressive changes in decay in maple trees were studied by comparing total activity of the decay community (as measured by carbon dioxide output of excised samples), water content, pH, and predominant microorganisms (as shown by isolation on malt agar) in zones selected across the pocket of decay.Four trees from which Fomes igniarius were isolated gave consistent results with alkaline pH, high moisture content, and a predominance of imperfect fungi in the zones of incipient decay. Surprisingly, these zones showed the highest rates of carbon dioxide output, though they were only slightly higher than those of the transition zones. The center, severely decayed, parts of the trees were slightly acid, appreciably drier, and contained F. igniarius in abundance. They showed only about half the rate of carbon dioxide production of the outer zones. A section of rot caused by Polyporus glomeratus corresponded in most respects to those with F. igniarius.In samples of two regions from which no basidiomycete decay fungus was isolated, the pattern was completely different. In these the pH was consistently alkaline all across the pocket, exceeding pH 9 in one central area, and was highest in the central zone. The moisture content of these two trees was very high, being highest in the central zones, and the carbon dioxide production was much higher than that of the F. igniarius decays.
The morphology of zoospores of Phytophthora megasperma var. sojae and other Phycomycetes
Authors: Ho H. H. , Hickman C. J. , Telford R. W.
Published: August 2008

Studies of the external morphology of some laterally biflagellate Phycomycete zoospores revealed a general similarity of zoospore shape, nature and position of groove, and insertion of flagella.
The systematics of the Asiatic and American populations of Fauria crista-galli (Menyanthaceae)
Authors: Gillett John M.
Published: August 2008

The genus Fauria Franchet (Menyanthaceae) with one species, F. crista-galli (Menzies ex Hook.) Mak., is divided into two subspecies, viz. the American subsp. crista-galli and the Asian subsp. japonica (Franch.) Gillett. Morphological characteristics of the two populations show certain quantitative differences. Chromosome numbers indicate that the Asian plant is tetraploid (2n = 68) and the American hexaploid (2n = 102). Direction of migration of the species was probably from west to east.
Aspects of the development and reproduction of Acrochaete repens and Bolbocoleon piliferum
Authors: South G. Robin
Published: August 2008

Acrochaete repens Pringsh. and Bolbocoleon piliferum Pringsh. endophytic in Chorda filum (L.) Stackh. are shown to be more variable in form than indicated by the original descriptions. Plants are present all year at Rhosneigr, Anglesey, North Wales, reaching their peak development at the end of the year and contributing to the annual breakdown and disappearance of C. filum sporophytes. Both species were isolated in culture. Reproductive bodies of A. repens germinated to produce a single generation of plants. Starting from a cushion of cells, an extensive upright system of filaments was produced, bearing hairs and sporangia containing non-viable swarmers. Two self-replicating, apparently asexual generations of B. piliferum were obtained. Quadriflagellate, non-pairing zoospores germinated into two forms of the parent type, one 'normal' with hair cells and hairs, the other 'reduced' and highly reproductive, with few hair cells or hairs. In both forms the essential characteristics of the species were preserved. Zoospores from the first generation were of the parent type, germinating into culture forms of either type. Culture plants of A. repens and B. piliferum ultimately developed into extensive filamentous systems scarcely distinguishable from one another. Since the two species occur in close association both in the field and in culture, the possibility that they may be parts of the life history of a single taxon cannot be ruled out.
Kellermania and its generic segregates
Authors: Sutton B. C.
Published: August 2008

The history of the generic names Kellermania Ell. & Ev., Chaetoconis Clements, Scolecosporiella Petrak non Höhn., Amphorula Grove and Brencklea Petrak is reviewed. Two species are included in Kellermania, K. anomala (Cooke) Höhn., and K. major Dearn. & Barth., and one in Chaetoconis, C. polygoni (Ell. & Ev.) Clements. Brencklea is reduced to synonymy with Scolecosporiella, and this genus enlarged to include three species, S. typhae (Oud.) Petrak, S. sisyrinchii (Ell. & Ev.) n. comb. (≡ Kellermania sisyrinchii Ell. & Ev.), and S. kranzii n. sp. Obstipipilus n. gen., type species O. malabaricus (T.S. & K. Ramakrishnan) n. comb. (≡ Kellermania malabarica T. S. & K. Ramakrishnan), is described. Six species described in or transferred to Kellermania are excluded from the genus.
Two new species of Oidiodendron from boreal forest soils
Authors: Morrall R. A. A.
Published: August 2008

Oidiodendron periconioides Morrall sp. nov. and O. chlamydosporicum Morrall sp. nov. are described from Canadian boreal forest soils. O. gracile Zhdanova is considered to be a nomen dubium.
Effects of D-galactose on the ultrastructure of bentgrass root apices
Authors: Endo R. M. , Thomson W. W. , Krausman Emmylou M.
Published: August 2008

To study the effects of growth-inhibitory concentrations of D-galactose on the morphology and function of organelles, thin sections of galactose-treated, KMnO4-fixed bentgrass (Agrostis palustris L.) root apices were examined in the electron microscope. Inhibitory effects were noted on root cap mucilage formation, cell plate formation, cell wall accretion, and the organelles associated with these processes such as the dictyosomes and the endoplasmic reticulum. These studies suggest that D-galactose inhibits root elongation by not only suppressing the synthesis of cell wall precursors—as evidenced by apparent reduction in the activity of the dictyosomes and root cap mucilage formation—but also the cellular processes involved in cell wall accretion and the formation of the cell plate.
The biosystematics of the genus Lotus (Leguminosae) in Canada. II. Numerical chemotaxonomy
Authors: Grant William F. , Zandstra Ilse I.
Published: August 2008

A thin-layer chromatographic study of fluorescent compounds present in native (L. denticulatus, L. formosissimus, L. micranthus, L. pinnatus, L. purshianus) and introduced (L. corniculatus, L. krylovii, L.pedunculatus, L. tenuis) Canadian species of Lotus has been carried out and relationships of the species have been determined on the basis of the coefficients of association of these compounds. Chemical identification of the compounds was not attempted, but test reagents indicated a number to be phenolics. The analysis supported the general taxonomic relationships of the species based on a morphological and cytological study. Of the native species, L. pinnatus and L. formosissimus were the most closely related, with a coefficient of association of 83.33. Lotus denticulatus, the only native species with a chromosome number of n = 6, in general showed lower coefficients of association with the n = 7 species. Of the introduced species, all of which belong to the L. corniculatus group with a basic chromosome number of 6, L. krylovii and L. tenuis had the highest coefficient of association, 75.86. Based on their coefficients of association, both of these diploid species were more closely related to the tetraploid L. corniculatus than to the diploid L. pedunculatus.
Observations on the occurrence of a species of Lomentaria in southern British Columbia and northern Washington
Authors: South G. Robin
Published: August 2008

A representative of the genus Lomentaria (order Rhodymeniales, family Champiaceae) is described from Gabriola Island, British Columbia, and reported from other localities in southern British Columbia and northern Washington. The plant is referred to L. hakodatensis Yendo, although with some uncertainty about species designation, as the specimens observed were entirely sterile. The entity would appear to be non-endemic and may be of recent introduction into the northeast Pacific.
Utilization of different carbon sources by the genus Linderina
Authors: Chan Christina , Stephen R. C.
Published: August 2008

Representatives of the major groups of carbon-containing substances were tested against dextrose as the standard source. In general, the two species of Linderina responded in a similar way and all compounds tested could be utilized at least to some extent.Carbohydrates proved to be utilized best and gave the highest yields, the hexose monosaccharides, disaccharides, and some polysaccharides being rather better than the pentose monosaccharides and the trisaccharide raffinose. Organic acids were not as efficient as the better carbohydrates but gave moderate to good yields whereas the sugar acids and alcohols were much poorer. The single glucoside tested gave the lowest yield.
Plastids and mitochondria in the phloem of Cucurbita
Authors: Esau Katherine , Cronshaw James
Published: August 2008

Contrary to some statements in the literature, the sieve elements of Cucurbita maxima Duchesne contain plastids. In young cells these organelles resemble mitochondria with regard to size and density of the matrix; but they have fewer internal membranes. During cell maturation, the plastids enlarge and their contents become thin and electron-transparent. They assume a partly degenerated appearance and do not deposit starch. The plastids of the companion cells resemble those of the young sieve elements but develop a considerable number of internal membranes, which may be organized into typical chloroplast grana. Starch is rarely encountered in these plastids. The plastids of the phloem-parenchyma cells are chloroplasts, commonly including starch grains. The mitochondria are similar in the three categories of cell but those of the sieve elements may show a denser matrix in young cells and structural abnormalities in mature cells.
Chemosystematic studies in the genus Picea (Pinaceae). IV. The introgression of white and Engelmann spruce as found along the Bow River
Authors: Ogilvie R. T. , Rudloff E. von
Published: August 2008

The leaf oil of the spruces found along the Bow River from the foothills to Bow Summit was analyzed by gas–liquid chromatography. The terpene distribution patterns obtained were compared with the morphological data derived from the cones and twigs of the same trees. The results obtained confirm that typical white spruce occurs at low elevation whereas active hybridization with Engelmann spruce occurs at levels above 5000 ft. Although the trees at the timberline (7200 ft) had predominantly Engelmann spruce characteristics, much variation from tree to tree was encountered. In the terpene composition the quantitative variation was too large to permit conclusions about a typical Engelmann spruce terpene distribution pattern.
Tryptophan synthetase in shoot and root tissue of pea seedlings
Authors: Chen James , Boll W. G.
Published: August 2008

The occurrence of tryptophan synthetase in excised tomato root cultures (Lycopersicon esculentum Mill. var. Red River) and pea seedlings (Pisum sativum L. var. Alaska) was examined using cell-free extracts. No tryptophan synthetase activity could be detected in the former. Using serine-14C and indole-14C, with extracts from peas, it is shown by chromatographic and radioautographic methods that tryptophan is the product of the reaction, that both the substrates are necessary, and that pyridoxal phosphate is a necessary cofactor. Inhibition by metal ions, lability, thermolability, and various other properties are described. Partial purification was effected by gel filtration. The enzyme activity in pea root extracts, as measured by indole utilization per unit fresh weight, is much lower than in the enzyme preparations from terminal buds. A system causing destruction of indole, other than tryptophan synthetase, is also present in crude root extracts.
A model for the analysis of structure in taxonomic collections
Authors: Orloci Laszlo
Published: August 2008

Different numerical techniques are applied to a collection of specimens of the genus Phyllodoce Salisb. The results indicate that component analysis, cluster analysis, and subsequent discriminant analysis provide an informative model for the study of structure in taxonomic collections. Structure in such collections appears as trends in variation and tendency toward clustering.
Fungal elements from the Edmonton Formation (Maestrichtian), Alberta, Canada
Authors: Srivastava Satish K.
Published: August 2008

Seven species of fossil fungal spores belonging to three form-genera are described from the Edmonton Formation (Maestrichtian), Alberta. The stratigraphic significance of fossil fungi in general is discussed.
Seed exudates from Pinus resinosa and their effects on growth and zoospore germination of Pythium afertile
Authors: Agnihotri V. P. , Vaartaja O.
Published: August 2008

The role of exudates from germinating seeds of red pine, Pinus resinosa Ait., was examined in relation to zoospore germination and growth of Pythium afertile Kanouse and Humphrey. By paper chromatography, 14 amino acids, 4 sugars, and 3 organic acids were identified in the seed exudate. Among the sugars, glucose, fructose, and sucrose were detected in large amounts and arabinose in small amounts. Of 14 amino acids identified, threonine, lysine, arginine, and glutamine were present in trace amounts; leucine, γ-aminobutyric acid, valine, asparagine, and alanine in large amounts; and proline, serine, glycine, aspartic acid, and glutamic acid in small amounts. Of three organic acids detected, malonic acid was most abundant whereas citric and fumaric acids were present in small and trace amounts, respectively.When supplied singly, all sugars and amino acids, except alanine, threonine, γ-aminobutyric acid, and arabinose stimulated mycelial growth and germ tube growth of P. afertile. Organic acids promoted no growth and inhibited zoospore germination. Mixtures of sugars and mixtures of three or four amino acids effectively stimulated growth of mycelium and germ tubes. One to three germ tubes were produced with certain amino acids and sugars but only one germ tube with others. There was no correlation between the percentage zoospore germination and length of germ tube.
Growth responses of Pinto bean and alfalfa to sublethal fluoride concentrations
Authors: Treshow Michael , Harner Frances M.
Published: August 2008

Empirical observations of several species of plants fumigated with fluoride during a 10-year period have shown these to grow more rapidly than non-fumigated control plants. The present study was initiated to determine quantitatively the validity of these observations on Pinto bean (Phaseolus vulgaris L. var. Pinto) and alfalfa (Medicago sativa L.). When plants were fumigated with fluoride, growth was accelerated and internode development was conspicuously greater than in control plants. Fresh and dry plant weights were positively correlated with increasing fluoride content of the leaves. Statistically significant correlation coefficients of 0.91 and 0.98 were calculated between fluoride content and fresh and dry weights, respectively. When fluoride content exceeded approximately 200 p.p.m., weights decreased below those of the controls. Leaf chlorosis did not develop until foliar fluoride concentrations exceeded approximately 500 p.p.m.Fluoride sometimes stimulated growth of alfalfa plants but results were inconsistent and no statistically significant relation existed between foliar fluorides content and plant weights. However, dry weight of plants analyzing over 500 p.p.m. fluoride was only 63% that of the control plants despite the absence of any chlorosis or necrosis.
Chlorophyll changes, photosynthesis, and ultrastructure of chloroplasts in Albugo candida induced "green islands" on detached Brassica juncea cotyledons
Authors: Harding Howard , Williams Paul H. , McNabola Sharon S.
Published: August 2008

Brassica juncea cotyledons were detached from the plant 3 days after inoculation with Albugo candida. Changes in chlorophyll content of infected and noninfected tissue were determined over a 4-day period, during which time distinct "green islands" developed. Following incubation with glycine-2-14C in the light, radioactivity was detected in chlorophylls a and b of both infected and noninfected tissue. Both infected and noninfected tissue fixed 14CO2 in the light during the 4 days after detachment. Most of the incorporated activity was in the 70% ethanol-soluble fraction. At 4 days after detachment, "green islands" fixed 5 times more 14CO2 in the light than noninfected tissue while both types of tissue fixed about the same amount in the dark. Photosynthesis per mole of chlorophyll fell at the same rate in "green island" and noninfected tissue. The maintenance of chlorophyll and continued photosynthetic activity in "green islands" paralleled delayed chloroplast breakdown. "Green island" chloroplasts still had intact grana and relatively small osmiophilic globules 96 h after detachment. In noninfected tissue, grana began to break down and osmiophilic globules increased in size 48 h after detachment. At 96 h after detachment, little grana structure remained and chloroplasts contained greatly enlarged osmiophilic globules interspersed with strands of stroma lamellae. Tissue treated with kinetin responded in essentially the same way as "green island" tissue. Chlorophyll content and photosynthetic capacity were maintained and chloroplast breakdown was delayed.
New species of marine algae from California
Authors: Hollenberg George J. , Abbott Isabella A.
Published: August 2008

Eleven new taxa are described from California; two species, in addition, have new varieties added to them; and two species are given new circumscriptions to include a number of entities previously known under other names. New species are described in Percursaria (Chlorophyta), in Feldmannia (Phaeophyta), and in eight genera (Membranella, Porphyra, Rhododiscus, Peyssonelia, Prionitis, Blinksia, Besa and Rhodoglossum) of Rhodophyta. Two monotypic genera of Rhodophyta are described for the first time. One, Membranella nitens, is added to the Bangiales, and the other, Blinksia californica, is the type for a new family, the Blinksiaceae (Gigartinales). Half of the species of red algae are crustose non-corallinaceous species.
Factors limiting the survival of Ascochyta spp. of peas in soil
Authors: Wallen V. R. , Jeun Julie
Published: August 2008

A. pinodella and A. pinodes survived over a 12-month period in inoculated sterile soil maintained at a temperature range of −20 to 25 °C. Cultures isolated from soil from −20 °C to 15 °C were pathogenic; however, cultures isolated from soil at 5 and 10 °C were more virulent. A. pisi survived in soil at −20 and 5 °C for 12 months but only cultures isolated from −20 °C soil were pathogenic. The ability of soil cultures A. pinodella and A. pinodes to form chlamydospores is considered to a be a factor in their survival over this period of time and temperature range. No chlamydospores were formed in soil cultures of A. pisi. A. pinodella and A. pinodes were both antagonistic to A. pisi in sterile soil plates and A. pinodella was antagonistic to A. pinodes. Ascochyta spp., either A. pinodella or A. pinodes, were isolated from 18 of 46 soil samples collected from many areas in Canada. Soil cropped to corn contained fewer Ascochyta propagules than did soil cropped to beans, turnips, or peas; the latter soils contained the most propagules.
Chromosome numbers of Texas grasses
Authors: Gould F. W.
Published: August 2008

Records for 409 of 572 native and introduced grass species of Texas show that 30% are diploid, 30% are tetraploid, 11% are hexaploid or of a higher level of ploidy, and 29% have two or more ploidy levels. The relatively high percentage of diploids is due to the large number (40 species) of diploid panicums. In the present report a total of 304 chromosome counts are presented for 140 species. Chromosome counts for the following 22 species are the first for the taxon or different from previous records: Sitanion longifolium, Agrostis hiemalis, Axonopus affinis, Echinochloa walteri, Panicum hemitomon, P. thurowii, Eragrostis intermedia, E. swallenii, Neeragrostis reptans, Sporobolus asper, Tridens ambiguus, T. muticus, T. strictus, Triplasis purpurea, Bouteloua hirsuta, Chloris latisquamea, C. verticillata, Gymnopogon ambiguus, Hilaria mutica, Spartina alterniflora, S. patens, and Trichloris pluriflora. The records of 2n = 60 for Neeragrostis reptans, 2n = 40 for Triplasis purpurea, and 2n = 40 for Gymnopogon ambiguus are the first for the genera Neeragrostis, Triplasis, and Gymnopogon.
Xylaria curta: cytology of the ascus
Authors: Rogers Jack D.
Published: August 2008

Cytological results, including frequent multivalents, indicate that Xylaria curta is polyploid. The ascospores, at first uninucleate, become binucleate; one nucleus is then lost via an evanescent appendage at an early stage of spore development. Maturing ascospores are uninucleate. The possible significance of these findings is discussed.
The life cycle and cytology of Brachyallomyces
Authors: Wilson Charles M. , Flanagan Patrick W.
Published: August 2008

Studies of nuclear and chromosome behavior in the resistant sporangia and hyphae of Brachyallomyces reveal two ways by which the life cycle of this water mold is maintained without a sexual phase. In certain isolates meiosis occurs in the resistant sporangia with subsequent apomixis in the resistant sporangium zoospores, returning the germlings to the sporophytic phase. In other isolates mitosis occurs in the resistant sporangia and meiosis is excluded from the life cycle. Two methods for inducing the gametophytic phase into the life cycle are described. In one method the resistant sporangia were germinated in 0.02 M K2HPO4 solution and gametophytes were obtained from germlings of the resistant sporangia zoospores. The other method was to cut hyphal tips from 4-day-old colonies of sporophytes growing on agar and transfer. By both methods the number of gametophytes obtained was extremely small.
Rhytidiella moriformis n. gen., n. sp. causing rough-bark of Populus balsamifera
Authors: Zalasky H.
Published: August 2008

Rhytidiella moriformis n. gen., n. sp. is a parasite which causes perennial rough-bark of Populus balsamifera L. The fungus produces perfect and imperfect states in nature. Cultural studies show that the macroconidia belong to the form-genus Phaeoseptoria Speg.
Myrtle Lake: a late- and post-glacial pollen diagram from northern Minnesota
Authors: Janssen C. R.
Published: August 2008

A pollen diagram from a lake in the former bed of the eastern arm of Lake Agassiz in northern Minnesota records a vegetation of spruce forest followed by immigration successively of Pinus banksiana and (or) P. resinosa at 10 000 B.P., then Abies and Pteridium, and still later Alnus. Between 8000 and 7000 B.P. prairie and (or) Quercus savanna prevailed on the uplands, followed by deciduous forests of mainly Quercus, Ostrya virginiana, Fraxinus pennsylvanica, and possibly Populus sp.Slightly later, Pinus strobus migrated into the area, resulting in a gradual decline of pollen of deciduous forest types. Betula pollen, however, rises, and there is an indication of a return to prairie conditions prior to 3000 B.P.During the 8000–7000 B.P. dry interval the lowland vegetation consisted of fens of Typha latifolia, Dryopteris thelypteris, and Cyperaceae. Later paludification and lateral expansion of the peatland gave rise to rather rich swamps of Picea mariana, Larix laricina, Alnus rugosa, and Thuja occidentalis. There are some conspicuous peaks of Myrica in the pollen diagram.The time after 3000 B.P. is characterized by much Pinus strobus pollen and minima of deciduous trees and herbs. In the lowlands, formation of raised bogs and poor swamps and fens began, indicating a shift in climate towards wetter conditions. The arrival of white man in the area is reflected by the rise of Ambrosia. The shifts in overall peatland types are clearly accompanied by changes in the species composition of Pediastrum in Myrtle Lake, indicating corresponding changes in the lake waters.
Chromosome numbers and phylogeny in Caragana (Leguminosae)
Authors: Moore R. J.
Published: August 2008

Chromosome counts for 17 species of Caragana are given. The chromosome numbers of the following species are reported for the first time: C. ussuriensis, 2n = 48, and C. brevifolia, C. maximowicziana, C. pleiophylla, C. conferta, C. tangutica, C. pekinensis, all 2n = 16. Remarks on the taxonomy of some species are presented. Cytology and morphology, as related to phylogeny of the genus, are discussed and a scheme of the evolution of Caragana is advanced.