bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology of conidia of Cochliobolus sativus from untreated and fungicide-treated barley seed
Authors: Mills J. T.
Published: September 2008

Conidia of Cochliobolus sativus from untreated seed are straight, curved, or occasionally triradiate, are multicellular, and produce bipolar germ tubes, but aseptate conidia of different sizes also occur. A narrow channel or plate occurs at the position of invagination between outer and inner layers of endospore wall. Conidiophores from untreated or treated seeds are pitted as seen in electron micrographs. Multiradiate conidia with reduced lumina occur after treatment with Panogen Px and conidia from Panogen Px, Polyram 80, and Dithane M45 treatments produce lateral or bipolar germ tubes. Brown bands, coincident with the channel or plate, occur in conidia exposed to Res-Q, Polyram 80, Dithane M45, SWF 790, SWF 810, and SWF 840 treatments. Obovate conidia occur on Hexa-treated seed. Evidence is presented suggesting that fungicides enter the conidia via terminal germination areas rather than the conidiophore.
Quantitative relationships among vegetation and soil classifications from northeastern Minnesota
Authors: Grigal D. F. , Arneman H. F.
Published: September 2008

A number of classifications of 40 upland forest stands from northeastern Minnesota were carried out and the results were compared. Numerical classifications based on various vegetation properties, on soil properties, and on synthesized environmental gradients of heat, moisture, and nutrients, and non-numerical classifications based on cover type and soil were examined.The vegetation classification based on frequency of all vascular species, excluding those occurring in only one stand, was most closely related to the other vegetation classifications, to the soil classifications, and to the environmental classification. Classifications based on overstory vegetation were poorly related to both those based on soil and on environment. In the study area, overstory composition is relatively insensitive to soils and environment. The numerical classification based on all 22 soil properties which were measured was more closely related to the vegetation classifications than was the non-numerical soil classification based on a few "diagnostic" properties. To find relationships between various classifications of natural systems, it is necessary to use both relevant properties and a correct scale of classification.
Some setose Hyphomycetes of leaf litter in south India
Authors: Pirozynski K. A. , Patil S. D.
Published: September 2008

Twenty species of setose Hyphomycetes occurring in leaf litter in south India and belonging to the genera Beltrania, Beltraniella, Circinotrichum, Codinaea, and Gyrothrix are recorded or described. Included are Beltrania mundkuri sp. nov., B. santapaui sp. nov., Beltraniella nilgirica sp. nov., B. porosa sp. nov., B. portoricensis (F. L. Stevens) comb, nov., Circinotrichum poonense sp. nov., C. pseudocladum sp. nov., and Codinaea maharashtrensis sp. nov.
Microradioautography of potato leaves inoculated with 3H-labeled conidia of Phytophthora infestans
Authors: Sivak Bela , Shaw Michael
Published: September 2008

Leaves of Solanum tuberosum var. Green Mountain were inoculated with leucine-3H or cytidine-3H labeled spores of Phytophthora infestans. Microradioautography showed that such spores germinated and developed an extensive radioactive intercellular mycelium but the release of radioactive substances, and their transfer to host organelles were not detected. Possible explanations are discussed briefly.
Pure culture synthesis of ectomycorrhizae by Thelephora terrestris and Pisolithus tinctorius on different conifer hosts
Authors: Marx Donald H. , Bryan W. Craig
Published: September 2008

In a special plant-growth room, isolates of Thelephora terrestris produced basidiocarps and formed typical ectomycorrhizae with seedlings of bristlecone, jack, sand, lodgepole, shortleaf, slash, sugar, Austrian, longleaf, cluster, ponderosa, red, pitch, eastern white, Scots, loblolly, and Virginia pines and Douglas fir. Atypical mycorrhizae (lacking mantle) were formed on seedlings of Norway spruce and jack, Japanese red, and Himalayan pines. The formation of atypical mycorrhizae was considered a result of differences in the symbiotic–parasitic nature of the fungal symbionts on different hosts. Pisolithus tinctorius formed typical mycorrhizae with seedlings of jack, sand, Japanese red, shortleaf, slash, Austrian, longleaf, cluster, red, pitch, eastern white, Scots, loblolly, and Virginia pines. Reisolation of specific fungal symbionts from mycorrhizae of several pine hosts was successful.Mycorrhizae formed by T. terrestris were macroscopically and microscopically different from those of P. tinctorius, but mycorrhizae formed by different isolates of T. terrestris were indistinguishable from each other, regardless of host. These results suggest that the fungal symbiont determines color and morphology of ectomycorrhizae.
The effect of four audible sound frequencies on the growth of Marquis spring wheat
Authors: Measures Mary , Weinberger Pearl
Published: September 2008

The effect of 300 Hz, 1250 Hz, 5 kHz, and 12 kHz sound frequencies on the growth of Marquis spring wheat was investigated. Sound was added only during an extended (4-week) chilling period.The height, number of roots, number of tillers, and fresh and dry weights of the root and shoot systems were significantly larger in plants pretreated with 5 kHz sound, when compared with controls. The height, dry weight of roots, and fresh and dry weights of tops were also significantly larger in plants pretreated with 300 Hz sound. Plants pretreated with either 1250 Hz or 12 kHz frequencies did not differ significantly from controls.
Seedling establishment in Psittacanthus (Loranthaceae)
Authors: Kuijt Job
Published: September 2008

The haustorium of Psittacanthus allenii Woodson and Schery, in contrast to other primary mistletoe haustoria, originates subterminally from the flanks of an extremely short radicle, the summit of which is occupied by the persistent remnant of the multicellular suspensor. The standard features of Santalalean haustoria, such as collapsed zones, glands, and repetitive intrusive organs, are present. The host cambium is displaced upward from below the successful intrusive organ, but continues its activity. The bulbous base of the mistletoe forces the expanding host cambium to fold back, resulting in the formation of a funnel-like wooden cup or woodrose. In subsequent years the host cambium deposits additional increments on the outside of the woodrose, each one enlarging the latter's diameter. The upper, internal margin of the woodrose provides an absorptive front of the newest host wood with the last marginal increment of vascular bundles of the haustorium itself. The haustorium of Psittacanthus, although not a modification of the most terminal portion of the radicular apex, may nevertheless be regarded as a primary haustorium, as it arises from the apical area of the radicular pole.
In vitro culture of the flax rust, Melampsora lini
Authors: Coffey M. D. , Bose A. , Shaw Michael
Published: September 2008

Two different strains of Melampsora lini (Pers.) Lév. were grown on media similar to those described by Turel (Can. J. Bot. 47: 821–823). Alterations in organic and inorganic constituents did not, in general, prevent growth. Peptone and yeast extract, singly or in combination, supported growth, but coconut milk did not. Maintenance of the ambient temperature below 17 °C during transfer procedures increased the number of colonies which grew. The mycelium was generally binucleate. Spore-like cells of varying shapes were found, some of which resembled uredospores and teliospores.
Automatic classification of plants based on information content
Authors: Orloci Laszlo
Published: September 2008

An information theory model is described and its application is illustrated by an actual example. Classification is accomplished in two stages. The first stage includes cluster analysis of a random sample by an agglomerative method. Cluster analysis is followed by nearest neighbor sorting in the second stage whereby the clustering results are imposed on a second random sample of the same collection. The advantage of the procedure resides in the fact that large samples can be handled, and also, the classification produced in the second stage can be used, under specific restrictive assumptions, for unbiased prediction of different population properties. While the present paper is principally concerned with the technique itself, some taxonomic conclusions are also given.
Inflorescence initiation and endogenous gibberellin content of Red Wing azaleas (Rhododendron cv.) as influenced by succinic acid 2, 2-dimethylhydrazide
Authors: Godkin Sharon E. , Ballantyne David J.
Published: September 2008

The anatomy of inflorescence initiation and early flower development of the Red Wing azalea (Rhododendron cv.) is described.Gibberellic acid (GA3) completely prevents the induction of inflorescence initiation by succinic acid 2, 2-dimethylhydrazide (B-9), and also prevents natural induction and initiation.Dwarf pea epicotyl bioassays of eluates from thin-layer chromatograms of ethyl acetate extractions from immature leaves revealed several acidic and basic gibberellin-like substances. A cucumber hypocotyl bioassay detected a basic phytoactive substance. Some of the basic gibberellin-like substances may be involved with inflorescence development.B-9 does not induce inflorescence initiation by decreasing the levels of endogenous ethyl acetate soluble gibberellins. Basic gibberellin-like substances appear after B-9 treatment.
Crucibulum parvulum, a very small new bird's nest fungus from northwestern North America
Authors: Brodie Harold J.
Published: September 2008

A hitherto un-named species of Crucibulum is described and named C. parvulum. It grows in arid or in exposed areas of western Canada and northwestern United States, usually on dead plant stems. Its fruit bodies are among the smallest of the genus known; they are grey or pale buff, thin-walled, strongly obconic and have a delicate tomentum and small peridioles. These and other characters distinguish it clearly from C. laeve. C. parvulum failed to show any fertility when attempts were made to cross it with C. laeve. C. parvulum is heterothallic and tetrapolar.
Metabolic responses of bush bean plants to naphthenate application
Authors: Fattah Q. A. , Wort D. J.
Published: September 2008

A 0.5% aqueous spray of potassium naphthenates was applied to the foliage of 14-day-old plants of bush bean, Phaseolus vulgaris L. cultivar Top Crop, and the plants were then grown under light intensities of 16.1, 10.76, and 5.38 klx at 26 °C for 7, 14, and 21 days. Photosynthesis, dark respiration, and phosphorylase activity were significantly greater (0.05 level) in treated plants at the end of all three growth periods under all light conditions. Significant stimulation of phosphoglycerate kinase developed more slowly under the lower light intensities. The stimulation of nitrate reductase and glutamic–pyruvic transaminase in treated plants reached a significant level between 7 and 14 days after treatment, and subsequently increased. The percentage increases of all the processes, over corresponding values in control plants, were greatest in plants grown at the highest light intensity.
Spontaneous variability of single isolates of Phytophthora infestans. II. Pathogenic variation
Authors: Caten C. E.
Published: September 2008

The variation in two aspects of pathogenicity, aggressiveness and virulence (physiologic race), among single zoospore cultures from three wild isolates has been examined. Two components of aggressiveness were measured, rate of growth on tubers and generation time on detached leaflets. Virulence was assessed from the pattern of compatible and incompatible reactions to members of the R gene differential series. Extensive variation in aggressiveness was detected in samples of zoospore cultures from all three isolates. The level of aggressiveness ranged from a high, equivalent to that of the parental wild isolates, to a complete lack of pathogenicity; as much as 45% was of the latter type. No instance of a change in virulence was found among 104 cultures tested.The significance of the observed pathogenic variation is discussed. It is concluded that zoospore variation is not important as a source of new physiologic races or strains adapted to particular, horizontally resistant varieties. Comparison of populations of zoospore cultures with samples of wild isolates suggests that directional selection for high growth rate and high and rapid sporulation operates in nature. The correlations between a number of cultural and pathogenic characters are examined, and an association between abundant sporulation in culture and high aggressiveness demonstrated.
Dissemination of fungi by migratory birds: survival and recovery of fungi from birds
Authors: Warner Gloria M. , French D. W.
Published: September 2008

Spores of Cladosporium resinae and Aspergillus giganteus applied to feathers of 149 birds of 31 species were recovered in a viable condition from 18 of these birds 3–45 days later. Fungi in 39 genera, including some plant pathogens, were isolated from the feathers of 248 birds collected in Minnesota, Texas, and Mexico. Puccinia coronata and Helminthosporium avenae were transmitted by grackles from infected oat plants in the field to 22% and 52%, respectively, of the greenhouse seedlings which were exposed to the birds.
Synthesis of asparagine from 14CO2 in wheat seedlings
Authors: Maxwell Margaret A. B. , Bidwell R. G. S.
Published: September 2008

Wheat shoots were supplied with 14CO2 during a light period (6–24 h), then placed in darkness for periods up to 48 h. During the dark period labeled sugars disappeared and labeled asparagine accumulated, suggesting the conversion of sugar carbon to asparagine. Sugars produced later in the dark period were preferentially used. Asparagine was formed throughout the plant. It was translocated out of the leaf blades but not to the roots. Glutamine was formed only in leaves, and translocated to both the stem and the root. The data suggest that glutamine is more important as a translocation form of nitrogen, while asparagine serves mainly as a storage compound.14C-Asparagine was biosynthesized from 14CO2 with higher yield and specific radioactivity than has been possible by previous methods.
Gene-for-gene relationships in the Avena: Puccinia graminis host–parasite system in Canada
Authors: Martens J. W. , McKenzie R. I. H. , Green G. J.
Published: September 2008

The results of 48 years of oat stem rust physiologic race surveys are interpreted in terms of the prevailing host genotype. Changes in the frequencies of genes that govern virulence in the pathogen can be explained only in part by changes in the resistance genes carried by the host population. Genes for virulence on newly released types of resistance have spread very quickly through the rust population, after initial 'breakdown' of the resistance. The most successful physiologic races carry genes for virulence in excess of those required for successful parasitism in North America. Many races carry genes for virulence on types of resistance that have never been used on this continent.
The genus Atriplex (Chenopodiaceae) in Canada. II. Four native western annuals: A. argentea, A. truncata, A. powellii, and A. dioica
Authors: Frankton C. , Bassett I. J.
Published: September 2008

Descriptions, illustrations, and distribution data are given for four annual species of Chenopodiaceae native to western North America: Atriplex argentea Nutt., A. truncata (Torrey) Gray, A. powellii Watson, and A. dioica (Nutt.) Macbr. All four species have the same chromosome number, 2n = 18. Scanning electron photomicrographs of the pollen grains are included.
Ascocarp development of two species of sooty molds
Authors: Corlett Michael
Published: September 2008

Ascocarp development of two species of sooty molds is described. A species of Aithalomyces has the Dothidea type of centrum organization with the pseudoparenchyma of the ascocarp centrum breaking down to produce a locule in which the asci develop. In Metacapnodium juniperi, the developmental pattern is of the Pleospora type, with the pseudoparaphyses growing down from the top and sides of the developing locule.
The Hardy-Weinberg law used to study inheritance of male inflorescence color in a natural Scots pine population
Authors: Carlisle A. , Teich A. H.
Published: September 2008

The frequencies of three Scots pine male inflorescence color variants in a natural Scots pine population indicated that the population was in Hardy-Weinberg equilibrium. Information can sometimes be obtained on the genetic constitution of a tree population without resorting to long-term progeny tests by examining frequencies of variants in this way. The method also indicates whether or not the character is controlled by only one gene.
The relationship of ammonia to symptom expression in apple shoots inoculated with Erwinia amylovora
Authors: Lovrekovich L. , Lovrekovich H. , Goodman R. N.
Published: September 2008

Apple stem tissue exposed to ammonia vapors reproduced the symptoms of fireblight. The stem tissue infected with Erwinia amylovora evolved sufficient amounts of ammonia to account for symptom development.
Movement within leaves and plants of 14C applied as 14CO2
Authors: Penny Pauline , Nelson C. D.
Published: September 2008

A study was carried out to determine how 14C applied as 14CO2 to a localized area of the leaf for 5 min moved to the rest of the leaf during the treatment period. It was concluded that 14CO2 diffuses from the application area to the rest of the leaf where it is fixed photosynthetically in the position detected by whole leaf autoradiography. These conclusions were deduced from experiments on darkening a portion of the leaf, comparing the radioactive compounds in treated and untreated areas of the leaf, and by using variegated Pelargonium leaves. Using the darkening technique, 14CO2 movement in the stem of soybean was not detected for 15 min after treatment of a primary leaf with 14CO2 in the light.
Taxonomy of Plicatura nivea (Aphyllophorales)
Authors: Ginns James H.
Published: September 2008

Differences found in both basidiocarps and cultures of Plicatura nivea (Fr.) Karst. (≡ Merulius niveus Fr.) and the type species of Merulius, M. tremellosus Fr., led to the exclusion of P. nivea from Merulius. After a study of type specimens, P. alni Peck, M. rimosus Berk, and, for the first time, Radulum cuneatum Lloyd, were placed in synonymy with P. nivea. P. nivea is tetrapolar, occurs north of 40° N latitude and may be further restricted to the range of its principal host Alnus.
Neogymnomyces, a new genus of the Gymnoascaceae
Authors: Orr G. F.
Published: September 2008

Four strains of Gymnoascus demonbreunii have been studied on various media at room temperature and at 37 °C. Ascocarps were produced on most media and naked mature asci on some media. No growth was demonstrated by any of the strains at 37 °C. Spore suspensions of the various strains were injected intraperitoneally into mice; most of the strains were recovered, but no lesions or other abnormalities were observed in any tissues.G. demonbreunii is shown to have no taxonomic relationship with Histoplasma capsulatum and is not the sexual state of that fungus. Comparisons of G. demonbreunii with species of Gymnoascus revealed significant morphological differences that require the inclusion of G. demonbreunii in a new genus, Neogymnomyces.
Two varieties of Rhizophydium sphaerocarpum (Chytridiales)
Authors: Barr D. J. S.
Published: September 2008

Two varieties of Rhizophydium sphaerocarpum (Zopf) Fischer are proposed: var. sphaerocarpum, saprophytic on algae, nematodes, and pine pollen; and var. spirogyrae, a parasite of Spirogyra spp. The varieties differ morphologically only in colony color and texture. Variety sphaerocarpum grew best at (10–) 15–20 C and used inorganic nitrogen as ammonium chloride, ammonium nitrate, and sodium nitrate when the inoculum contained actively growing thalli, whereas var. spirogyrae grew best at (25–) 30 C and did not use inorganic nitrogen. Results of pH range tests and carbon nutrition were very similar for the two varieties and both required exogenous thiamine.
Auxin catabolism and inhibitors in normal and crown gall tissues of Impatiens balsamina
Authors: Bouillenne Claire , Gaspar Thomas
Published: September 2008

Indoleacetic acid-like substances and hydronaphthoquinoneglucoside concentrations are higher in crown gall and other tissues of infected Impatiens balsamina than in corresponding tissues of non-infected plants.No difference can be found in indoleacetic acid (IAA) synthesizing capacity (from tryptophan) between tissues of normal and tumorous plants.Peroxidase and IAA oxidase in purified extracts of crown gall tissue are higher than in other tissues but only during the first stages of its development. Subsequently, their activity decreases while it continues to increase in leaves and stem.The results suggest participation of IAA oxidase inhibitors, particularly 1,2,4-trihydroxynaphthalene-4-glucoside, in establishing the higher IAA content of crown gall tissues.
Studies of intermediary metabolism in radish cotyledons. Turnover of photosynthetic products in 14CO2 pulse-chase experiments
Authors: Caballero A. , Cossins E. A.
Published: September 2008

Ability of 11-day-old radish cotyledons to carry out photosynthesis has been examined by supplying 14CO2 to cotyledon disks for periods ranging from 30 s to 20 min. Carbon-14 was rapidly incorporated into malate, citrate, sugar phosphates, and a number of amino acids. The kinetics of 14C incorporation suggest that carbon initially enters components of the organic acid and sugar phosphate fraction, being then rapidly transferred to the amino acids and sugars. In pulse-chase experiments, illuminated cotyledon disks were incubated with 14CO2 for 30 min then transferred to air containing 12CO2 for periods up to 240 min with illumination. During such postpulse incubations, considerable losses of 14C occurred from most of the principal compounds labeled during the chase incubation. As these losses were not entirely accounted for by losses of label to the incubation medium they can largely be attributed to metabolic turnover of these compounds. It is concluded that, in general, the photosynthesis of radish cotyledons is similar to that of mature leaves and of physiological significance as a route for synthesis of several important cellular constituents required for seedling growth and development.
Water deficit in plant communities
Authors: Gračanin M. , Ilijanić Lj. , Gaži V. , Hulina N.
Published: September 2008

Comparative investigations within the two different plant communities of Croatia (Fagetum silvaticae croaticum abietetosum Ht and Querco-Carpinetum croaticum erythronietosum Ht) indicate that (1) the two communities have their own range of water deficit values, (2) the Dw values are dependent on the capability of the species to regulate their water regime, (3) the same species behave differently within the two communities, (4) water deficit of leaves can be used as an indication of the water status of the site and plants, and consequently may have a significant place in the synecology and synchorology of plant communities.
Flower color in Fuchsia cultivars
Authors: Nozzolillo Constance
Published: September 2008

The color of the petals of two cultivars of Fuchsia which exhibit a color change with age was studied with respect to the pigments present and the pH of the cell sap at various stages of development. In both varieties, malvidin 3,5-diglucoside appeared to be the dominant pigment, with peonidin 3,5-diglucoside as a minor component. There appeared to be no change in the pigments themselves with age, although the color ranged from a blue in young flowers to a magenta in old flowers. This color change was correlated with a drop in pH from about 5.5 in young blue flowers to about 4.0 in old flowers, a drop which seemed to occur abruptly about the time of pollen release. The operation of a copigmentation effect was confirmed, and the presence of a copigment in addition to quercitin glucosides is suggested.
Sugars in the free space of leaf plates: their origin and possible involvement in transport
Authors: Kursanov A. L. , Brovchenko M. I.
Published: September 2008

A proportion (20–30%) of sugars is washed out from sugar beet leaf plates during a 30-min period of tissue rinsing with water. It is assumed that these sugars are compartmentalized in the free space (FS) of cells and that their leaching is not directly controlled by cell membranes. This fraction comprises sucrose, glucose, and fructose in ratios close to those characteristic for given cells.FS sugars interact with those compartmentalized in the cells. When mesophyll or conducting bundle tissues washed free of mobile sugars are placed for 15–30 min into a 0.002 M solution of 14C-sugars, the latter enter tissue FS and accumulate inside the cells. Conducting tissue cells show a much greater capacity for sugar absorption from FS than do mesophyll cells.When sugars are removed from the mesophyll FS. it is refilled with sugars from cells in 60 min. On repeated leachings of FS, about half of the sugars found in mesophyll cells may pass into FS. When conducting bundle tissues are leached, sugars can be removed only once from their FS. Keeping the leached bundles for an hour or more does not lead to their resaturation with sugars from the conducting cells. It may therefore be concluded, that in a whole leaf, the FS of conducting tissues is filled with sugars coming from mesophyll cells.After a 5-min photosynthesis in mesophyll disks in the presence of 14CO2, labeled assimilates are detectable in the FS of this tissue after as early as 10 min, while after 120 min the labeled products in the FS constitute over 40% of the newly-formed 14C-assimilates.It is suggested that in a whole sugar beet plant, assimilate outflow from leaf plates may occur with the participation of tissue “free space,” from which sugars are absorbed by a network of conducting bundles, thereby causing more amounts of sugars to come from photosynthesizing mesophyll cells.
The influence of red and blue light on the rate of photosynthesis and the CO2 compensation point at various oxygen concentrations
Authors: Voskresenskaya N. P. , Grishina G. S. , Chmora S. N. , Poyarkova N. M.
Published: September 2008

Apparent photosynthesis of attached leaves of Phaseolus vulgaris, Vicia faba, Pisum sativum, and Nicotiana tabacum at various intensities of blue and red light was measured by infrared CO2 gas analyzer in a closed system. Simultaneously the CO2 compensation point was measured.It was found that light-limited photosynthetic rate in blue light was equal to or more than that in red light. Inhibition of photosynthesis, which sometimes occurred at light-saturated intensities of blue light, could be avoided by addition of red light, prolonged exposure of the plants to blue light, or by lowering the O2 concentration. Accordingly, the increase of photosynthetic rate due to change of O2 concentration from 21 to 3% O2 is higher in blue light only when photosynthesis is inhibited by blue light at 21% O2. The data on the action of blue and red light on the CO2 compensation point seems to exclude the activation of photorespiration by blue light.The possible effects of blue light on apparent photosynthesis are discussed on the basis of the results presented.
14CO2 fixation in leaf discs of Phaseolus vulgaris
Authors: Tamas Imre A. , Bidwell R. G. S.
Published: September 2008

Leaf discs of Phaseolus vulgaris L. were exposed to 14CO2 in light, and transient changes in the radioactivity of photosynthetic intermediates were determined when illumination was interrupted or the CO2 concentration lowered. The responses of phosphoglyceric acid, hexose monophosphate, and ribulose diphosphate showed that the Calvin cycle operates in this tissue. Turning off the light caused a rapid drop in 14C-sucrose and in the total 14C-content of the tissue, with a simultaneous rise in radioactive alanine, glutamate, malate, and aspartate, suggesting the rapid entry of sucrose carbon into respiratory pathways. Lowering the CO2 concentration resulted in a transient rise in 14C-glycolate which was followed by a temporary increase in 14C-serine-glycine and in the ambient CO2 concentration. This supports the hypothesis that glycolate produced in photosynthesis is a substrate for glycine and serine synthesis as well as for CO2 evolution.
Sensitivity of the infrared CO2 gas analyzer to 14CO2
Authors: Bulley N. R. , Tregunna E. B.
Published: September 2008

The infrared CO2 gas analyzer (Beckman model 215) is only 5% as sensitive to 14CO2 as it is to 12CO2.
Pyrenomycetes of West Bengal (India)—II
Authors: Kar A. K. , Maity M. K.
Published: September 2008

Six new species of Pyrenomycetes from West Bengal (India) are described and illustrated: Astrocystis capparidis on Capparis horridaL., Botryosphaeria ingiae on Inga dulcis Willd., Ceratosphaeria ervatamiicola on Ervatamia divaricata Burhill., Gnomonia appendiculata on Rubus sp., Leptosphaeria puniciae on Punica granatum Linn., and Massarina capparicola on Capparis horrida L.
Bioassays of fungi isolated from Pinus contorta var. latifolia with pinosylvin, pinosylvinmonomethyl ether, pinobanksin, and pinocembrin
Authors: Loman A. A.
Published: September 2008

On 2% malt extract agar media containing 10% lodgepole pine heartwood meal, laccase-producing Peniophora pseudo-pini Weres. & Gibson and Fomes pini (Thore ex Fr.) Lloyd survived 400 p.p.m. of dispersed non-solvated pinosylvin, double the lethal dose of pinosylvin for these fungi on 2% malt extract agar. Non-laccase-producing Coniophora puteana Schum. ex Fr. survived 200 p.p.m. of pinosylvin on 2% malt extract agar containing 10% heartwood meal. The lethal dose of pinosylvin for C. puteana on 2% malt extract agar was 50 p.p.m.On 2% malt extract agar and on 2% malt extract containing 1% cellobiose, 200 p.p.m. of the flavanone pinocembrin permitted the survival of P. pseudo-pini in the presence of 200 p.p.m. of pinosylvin. F. pini survived 200 p.p.m. of pinosylvin on 2% malt extract agar containing 1% cellobiose. This fungus survived when 200 p.p.m. of the flavanone pinocembrin were added to 200 p.p.m. of pinosylvin on 2% malt extract agar.
Towards a mathematical model of limestone pavement vegetation. III. Estimation of the determinants of species frequencies
Authors: Yarranton G. A.
Published: September 2008

Models of the determination of the frequencies of 31 species of bryophytes, lichens, and algae in limestone pavement grikes were calculated by multiple regression. Independent variables were parameters of microclimate and surface pH. Percentages of variance accounted for varied from 14 to 72. In most cases the balance is attributable to replicate errors in the estimates of species frequencies and the abundance of zeros in the data. The models were used to predict species frequencies in other grikes, and in most species the mean difference between predicted and observed frequencies was less than 10%. Determinants of species frequency were found to be similar for species growing near the bottoms of the grikes but differed for those occurring near the tops.It is suggested that a two-phase analysis would be more informative than straightforward regression. In phase (a) the conditions under which the expected frequency is nonzero would be delimited; in phase (b) multiple regression would be performed on the observations falling within this region. This proposal is shown to be related to Hutchinson's concepts of fundamental and realized niches. It would also eliminate the problem of the multiple zero.
In vivo verification of Cronartium ribicola propagated on tissue cultures of Pinus monticola
Authors: Harvey A. E. , Grasham J. L.
Published: September 2008

Inoculations of western white pine seedling stems with rust-infected tissue cultures produced one successful rust infection after 5 months. The infection was typical of this rust (Cronartium ribicola J. C. Fisch. ex Rabenh.) and the presence of haustoria was confirmed. Infected cortex tissue from this seedling was used to reestablish the isolate on host tissues grown in vitro.
Polygalacturonase production by virulent and avirulent isolates of Sclerotium bataticola in culture and in sunflowers
Authors: Chan Yu-Ho , Sackston W. E.
Published: September 2008

Three isolates of Sclerotium bataticola virulent on sunflowers and one moderately virulent induced symptoms and were reisolated from all plants 30 days after inoculation. Two avirulent isolates produced no symptoms but were reisolated from some inoculated plants after 30 days. Dialyzed culture filtrates of all isolates showed exopolygalacturonase (exo-PG) and endopolygalacturonase (endo-PG) activity. Activity was highest in filtrates from virulent cultures. Exo-PG activity was detected in dialyzed extracts from sunflower plants 12 h after toothpick inoculation (TPI) with two of four virulent isolates and 42 h after unwounded stem base inoculation (USBI) with all four virulent isolates. Endo-PG activity in plant extracts was detected 12 h after TPI with three of four virulent isolates and 19 h after USBI with all four virulent isolates. No PG activity was detected in extracts from plants inoculated with two avirulent isolates or from uninoculated plants.
The effect of pea root exudate on the germination of Pythium aphanidermatum zoospore cysts
Authors: Chang-Ho Yung
Published: September 2008

Zoospore cysts of Pythium aphanidermatum germinated well without external nutrient supply, but pea root exudate increased percentage germination and germ tube growth. Zoospore cyst germination and growth varied with different concentrations of the substrate supplied. Alone, the neutral fraction (sugars) increased percentage germination but had little effect on germ tube growth; the cationic fraction (amino acids) suppressed germination and growth somewhat, except at very low concentrations; the anionic fraction (organic acids) mildly stimulated both processes. Neutral and anionic fractions combined approached the stimulatory effect of root exudate. Amongst the components of root exudate tested as pure chemicals, fructose, histidine, homoserine, proline, and tartaric acid promoted germination and growth at low concentrations. Alpha-alanine, glutamine, serine, and valine became stimulatory at high concentrations. A combination of glucose with one of the organic acids was more effective than either alone.
A survey of cell length and frequency of multiplicative divisions in the cambium of conifers
Authors: Bannan M. W.
Published: September 2008

Study of many species of conifers has revealed certain trends with respect to cell length and rate of anticlinal division in the multiplication of fusiform initials in the cambium. In the stem, rate of anticlinal division tends to be high when annual rings are narrow, and to stabilize at a relatively low level when rings exceed 2 mm in width. Cell length at division is usually greatest when rings are about 1 mm wide, and decreases with both widening and narrowing of the rings from the optimal width. Significant differences occur between species in both rate of anticlinal division and cell length. In general, rate of anticlinal division and cell length are inversely related, but in some species there is wide deviation from the common trend.
Systematic revision of Aquilapollenites Rouse 1957
Authors: Srivastava Satish K. , Rouse Glenn E.
Published: September 2008

The original diagnosis of the genus Aquilapollenites is inadequate. It is suitably emended here and a revised generic diagnosis is given. The validity of the genera Aquilapollenites and Pentapollenites is examined. It is concluded that Aquilapollenites has seniority over Pentapollenites.The holotypes of the type species Aquilapollenites quadrilobus and A. trialatus have been lost. These two species are redescribed in detail and their neotypes selected. A. formosus is described as a new species from the Upper Cretaceous Oldman Formation of Alberta.
The relationship between vegetative branch growth and subsequent bearing of megasporangiate strobili in slash pine
Authors: Varnell R. J.
Published: September 2008

Shoot growth of primary branches and subsequent bearing of megasporangiate strobili seem to be relatively independent of each other in slash pine growing in northcentral Florida. Only overall length and diameter at the branch base differed significantly between 44 bearing and nonbearing primary branches measured in 1964. In contrast, a strong relationship appeared between vigor and subsequent production of strobili on 273 secondary branches. The 1963 and 1964 shoots and the terminal buds were longer and thicker on branches which initiated strobili in 1964 than on branches which did not. Bearing secondary branches also had produced more flushes of growth in 1964 than nonbearing ones, and those with the most strobili had been more vigorous than those with few strobili.
Incorporation of 3H-deoxynucleosides: changes in labelling indices during root development
Authors: MacLeod R. D. , Davidson D.
Published: September 2008

Whole root systems of Vicia faba were treated with 3H-TdR (tritiated deoxythymidine), 3H-AdR (tritiated deoxyadenosine), or 3H-CdR (tritiated deoxycytidine) solutions for 1 h. Labelling indices were determined immediately after treatment or up to 15 h later. Cells of lateral root meristems labelled immediately and most effectively with 3H-TdR. Lower levels of labelling were found in roots treated with 3H-AdR or 3H-CdR; these precursors, in particular 3H-CdR, appear to be unsuitable for the determination of any parameter of DNA synthesis. Cells of small primordia showed poor incorporation of labelled precursors immediately after a 1-h treatment but their labelling indices increased subsequently. It is suggested that pools of 3H-TdR and 3H-AdR are maintained and drawn upon by small primordia. Large primordia showed little or no incorporation of labelled precursors. The different responses of mitotically active cells taken from various developmental stages of a lateral root suggest that alternative pathways for the synthesis of DNA precursors are used to different extents during morphogenesis; the interesting aspect is that such changes can occur over a small number of cell cycles in a population of actively dividing cells.
Cytology of Poronia oedipus and P. punctata
Authors: Rogers Jack D.
Published: September 2008

The chromosome numbers of Poronia oedipus and Poronia punctata are n = 7, based on counts made of pachytene and metaphase chromosomes. Mature ascospores of P. oedipus are binucleate; those of P. punctata are quadrinucleate. The taxonomic implications of the cytological results are discussed.
Cell wall thickenings in Geocaulon lividum (Santalaceae)
Authors: Warrington Patrick D.
Published: September 2008

The parasitic plant Geocaulon lividum of the Santalaceae has thickenings on the walls of parenchyma cells in the cortex and other tissues of the rhizome and short-shoot. These wall thickenings have not been previously reported in the anatomical literature. Microchemical investigations involving staining and solubility characteristics indicate that these wall thickenings are holocellulosic in nature but not composed of alpha-cellulose.
Adaptations of the photosynthetic apparatus of sun- and shade-grown yellow birch (Betula alleghaniensis Britt.)
Authors: Logan K. T.
Published: September 2008

Rates of apparent photosynthesis and dark respiration of 4-year-old yellow birch (Betula alleghaniensis Britt.) seedlings, grown in full light and shade (13% of full light), were measured with an infrared gas analyzer. Measurements were made periodically throughout the growing season, using either attached branches or entire seedlings. Effects of light intensities from 0 to 4500 ft-c on photosynthetic rates were studied, and comparisons made between young and old leaves and between photosynthetic rates in normal (300 p.p.m.) and saturating (1245 p.p.m.) CO2 concentration.The photosynthetic apparatus of yellow birch was found to adapt poorly to shaded conditions. In saturating light, the rate of apparent photosynthesis of young leaves of shade-grown seedlings was only half that of sun-grown seedlings; for old leaves the reduction was even greater. As a result, shade-grown seedlings had a lower photosynthetic capacity in saturating light despite their larger leaf area. In low light intensities, leaves of sun- and shade-grown seedlings had nearly the same rates of apparent photosynthesis. Rates of respiration of shade-grown seedlings were one-half those of sun-grown seedlings.When seedlings were exposed to light intensities comparable to those in which they were grown, their photosynthetic rates correlated with their dry matter production.When the CO2 concentration was raised to 1245 p.p.m., photosynthetic rates of leaves of sun- and shade-grown seedlings increased by the same relative amount. It is concluded that the poor adaptation of yellow birch to shade results from a reduction in content of carboxylating enzymes rather than changes in chlorophyll content or resistance to CO2 diffusion. Adaptations of yellow birch are contrasted with those of sugar maple (Acer saccharum Marsh.).
Microbodies and lipid bodies in the hyphal tips of Sclerotinia sclerotiorum
Authors: Maxwell Douglas P. , Williams P. H. , Maxwell Martha D.
Published: September 2008

Hyphal tips of Sclerotinia sclerotiorum grown on a carboxymethylcellulose agar medium were studied with interference contrast, phase contrast, and dark-field optics and with the electron microscope. Microbodies with hexagonal crystalline inclusions were most abundant in a zone 80–160 μ from the hyphal apex. It is suggested that these bodies are involved in synthetic and storage functions. Lipid bodies were identified by their fluorescence with Nile blue and by their refractivity using dark field optics. They were most abundant in the first 80 μ of the hyphal tip and are thought to originate in this zone. Nuclei were randomly distributed throughout the hyphal tip cell.
Studies on marine algae of Newfoundland. I. Occurrence and distribution of free-living Ascophyllum nodosum in Newfoundland
Authors: South G. R. , Hill R. D.
Published: September 2008

The free-living "beach form" of Ascophyllum nodosum (L.) Le Jol. ecad mackaii (Turn.) Cotton is described for the first time from 10 of a total of 60 Newfoundland localities investigated. Development and form of the free-living plants are similar to descriptions of British populations of the same entity, and the same ecological conditions appear to cause their development in both areas. Plants arise from fragments of attached plants and have flattened or terete branches which are markedly dichotomous in the advanced stages. In extreme forms a terete, highly dichotomous, and disoriented branching habit is adopted, resulting in globular thalli. Plants generally lack air-bladders and are seldom fertile in intermediate and advanced forms of the ecad. Populations occur in the mid intertidal zone in areas of extreme shelter near a freshwater source, and on muddy or sandy/mud substrates. Parasitic Polysiphonia lanosa (L.) Tandy is absent from ecad mackaii in Newfoundland.
Degradation of nootkatin by fungi causing black heartwood stain in yellow cedar
Authors: Smith Roger S. , Cserjesi A. J.
Published: September 2008

A method for the quantitative analysis of nootkatin from yellow cedar is presented. The decrease of nootkatin in yellow cedar colonized by six different strains of "black-stain" fungus is shown, two of these strains being very resistant to the tropolone in liquid culture.
Origin of the summer shoot of pinyon pines
Authors: Lanner Ronald M.
Published: September 2008

Shoot development in pines is usually a two-stage process, with buds formed in the summer and elongation delayed until the next spring. Summer shoots have been described which originate by precocious elongation of a bud, a process which may or may not be followed by organization of a new dormant bud. However, in several of the pinyon pines, and perhaps in other soft pines as well, summer shoots are formed without having first been present as a bud. These summer shoots are composed partially of internodes associated with terminal bud scales of the previous year, but mainly of internodes initiated and elongated concurrently in the spring and summer. The major lateral branches of the complex shoot have their origin in the summer shoots, laterals of the spring shoot apparently being inhibited. Short shoots and long shoots of the summer shoot have developmental schedules that contrast with those of the spring shoot.
Further studies of intermediary metabolism in radish cotyledons. The utilization of glycine, glyoxylate, and acetate by tissue disks
Authors: Cossins E. A. , Caballero A.
Published: September 2008

Micromolar quantities of 14C-labelled glycine, glyoxylate, and acetate were metabolized by disks of 11-day-old radish cotyledons. Time-course experiments with illumination showed that both glycine and glyoxylate were extensively converted into serine, into various organic acids, and to a lesser extent into sugars. Pulse-chase experiments in which glycine-2-14C was used indicated that the major labelled products of 30-min pulse feedings rapidly lost 14C on incubation of the tissues in unlabelled glycine. As these losses were not accompanied by corresponding accumulations of 14C in the medium, they were largely attributed to extensive metabolic turnover.A comparison of glycine and glyoxylate pulse feeding experiments in light and dark showed that slightly lower percentages of both substrates were incorporated into the sugars in the dark. Incorporation of glyoxylate-14C into the sugars was markedly stimulated in both light and dark experiments when the tissues were simultaneously incubated with unlabelled glycine. It is concluded that in radish cotyledons, as in leaves, glyoxylate and glycine are both effective precursors of serine. The synthesis of sugars from these substrates appears to occur by a pathway essentially different from the glycollate pathway.
Preferential C4-dicarboxylic acid synthesis, the postillumination CO2 burst, carboxyl transfer step, and grana configurations in plants with C4-photosynthesis
Authors: Downton W. J. S.
Published: September 2008

An oxygen-insensitive postillumination CO2 burst occurs in many plants with the C4-pathway of photosynthesis. C4-species with a postillumination burst synthesize mainly aspartate during very short term photosynthesis and have low levels of 'malic' enzyme (EC. 1.1.1.40) activity. It is postulated that the burst is CO2 which normally participates in the carboxyl transfer step of C4-photosynthesis. The burst is absent in C4-species that produce mainly malate in short-term photosynthesis. This group of plants has very high 'malic' enzyme activity. Transport of malate to the bundle sheath layer and its metabolism by 'malic' enzyme provides reducing power (NADPH2) as well as CO2 to the Calvin cycle. This combination of products may attenuate the postillumination burst. Some malate formers show extreme grana reduction in bundle sheath chloroplasts which, is associated with a low capacity for generating reducing power. Malate transport compensates for this lack of reducing power in sheath cells with agranal chloroplasts. Transport of aspartate or oxaloacetate to the sheath cells does not transfer reducing power. The sheath chloroplasts of aspartate formers have well-developed grana but some reduction in grana within mesophyll chloroplasts is apparent in certain species. This reduction may reflect a low demand for reducing power where the major C4-acid synthesized is aspartate rather than malate.