bluuebunny/crossref_metadata_2025 huggingface dataset:
Nematophagous fungi: a new Gonimochaete
Authors: Barron G. L.
Published: September 2008

Gonimochaete pyriforme is described as a new endoparasitic nematophagous Phycomycete parasitizing a species of Diploscapter. Gonimochaete pyriforme produces non-motile spores, each with a pronounced apical adhesive knob. Spores develop in aerial evacuation tubes, which later function as support stalks for the evacuated spores.
Germination of hydrated uredospores of Puccinia recondita inhibited by light
Authors: Chang Ho-Shii , Calpouzos L. , Wilcoxson Roy D.
Published: September 2008

Germination of uredospores of Puccinia recondita was inhibited in the violet, red, and far-red portions of the light spectrum but not in the green and blue-green portions. Light was inhibitory only during the early phases of germination, before germ tubes were one-third the spore length. Light was inhibitory only when uredospores were hydrated before being exposed to light. As the length of the hydration process and the light intensity increased, the germination percentage decreased.
Development of vesicular-arbuscular mycorrhizae in crop plants
Authors: Sutton J. C.
Published: September 2008

Vesicular-arbuscular mycorrhizae developed extensively in a wide range of crop plants grown in field plots and in controlled environment. At 25–28 days after sowing, generally few roots (0.6–19%) were colonized by the mycorrhizal fungus Endogone. The proportion of roots colonized subsequently increased rapidly to maximum levels ranging from 48 to 84%. A three-phase pattern of mycorrhizal development involving sequentially a lag phase, a phase of extensive development, and a phase of constancy in the proportion of mycorrhizal to non-mycorrhizal roots was found in bean (Phaseolus vulgaris L.) and soybean (Glycine max (L.) Merr.). A similar multiphase development of mycorrhizae was evident also in some other hosts. The relationship of the different phases of mycorrhizal development to physiological changes in the host is discussed.
Growth of Aphanomyces cochlioides in synthetic media as affected by carbon, nitrogen, methionine, and trace elements
Authors: Herr Leonard J.
Published: September 2008

Aspects of the nutrition of Aphanomyces cochlioides were investigated using a synthetic medium containing the major elements (ME) C, N, S, Ca, K, Mg, P; with or without the trace elements (TE) Fe, Zn, Cu, B, Mn, Mo. Primary C, N, and S sources were D-glucose, L-asparagine or DL-glutamic acid, and DL-methionine. In the presence or absence of individual trace elements, growth increased with Fe, decreased with Cu, and was unaffected by the remaining trace elements. Combining Fe with Cu eliminated the toxicity of Cu. C, N, and methionine concentration level effects were studied in relation to trace element nutrition and N sources in a series of factorial experiments. Trace elements strongly affected growth (maximum yield minus TE = 21.0 mg; maximum yield plus TE = 139.7 mg). As a source of C, glucose supported greater growth (83 mg) than sucrose (18 mg), while growth without added C was poor (7 mg). L-Asparagine was superior to DL-glutamic acid as a source of N at high C levels and the effect of methionine concentrations on growth differed with the N source. D-Asparagine was not utilized as a source of N. Growth in the synthetic medium approached that obtained in a complex medium.
Nematophagous fungi: Rhopalomyces elegans
Authors: Barron G. L.
Published: September 2008

Rhopalomyces elegans is known to be a parasite of nematode eggs. This species is now found to be capable of capturing and parasitizing both the larval and adult stages of a species of Rhabditis. Penetration from an appressorium is followed by considerable subcuticular growth before death and colonization of the host. The presence of functional anastomoses is demonstrated in the vegetative hyphae of this mucoralean fungus.
Cotton grass (Eriophorum vaginatum) germination requirements and colonizing potential in the Arctic
Authors: Wein Ross W. , MacLean D. A.
Published: September 2008

Germination requirements of cotton grass (Eriophorum vaginatum L.) were investigated to determine its potential for reseeding disturbed areas of the arctic tundra. Maximum seed production was 15.7 kg/ha, although production and viability varied widely. There was no seed dormancy and temperatures of 25–30 °C produced maximum germination rates. A light treatment enhanced germination but was not required. Cotton grass seed germinated under less favorable moisture conditions than several other native grasses that strongly invade disturbed arctic sites. Loss of viability during storage under room conditions was high for the first 10 months, yet 27.6–52.5% of the seed remained viable at 19 months. The role that this species could play in revegetation is discussed.
Fungi associated with subcrown internodes of wheat (Triticum aestivum)
Authors: Harding Howard
Published: September 2008

Bipolaris sorokiniana was isolated, using a low nutrient medium, from about 80% of over 30 000subcrown internodes of wheat plants grown in 1971 and 1972. In 1972, almost 60% of the internodes rated "clean" yielded B. sorokiniana. There was little evidence of any antagonism between other groups of fungi isolated and B. sorokiniana. It is concluded that B. sorokiniana is a very successful parasite.
Two cytological responses in corn resistant to Helminthosporium maydis
Authors: Blanchard Robert O.
Published: September 2008

Collapse of cell walls and formation of uncharacterized intercellular material occurred in leaves of a resistant corn inbred, but not in a nearly isogenic susceptible line, within 48 h after inoculation with race T of Helminthosporium maydis. Both reactions started at the edges of lesions in advance of invading mycelium.
Genetics of cone morphology in white spruce (Picea glauca)
Authors: Khalil M. A. K.
Published: September 2008

A study was conducted in 1971 to estimate the degree of genetic control on the characters of cone morphology of white spruce (Picea glauca (Moench) Voss) from two areas of central Newfoundland and to determine whether these characters were associated with phenotypic superiority in growth. Hierarchical sampling was done, selecting two locations, two populations at each location, five trees in each population, and 20 cones from each tree. Ten characters were studied. Statistical analysis techniques used were calculation of repeatability as an estimate of heritability, hierarchical analysis of variance, and comparison of the populations of "ordinary" and "plus" trees, using Student's ‘t’ and Snedecor's 'F' tests.The results indicate that most of the 10 characters studied are under strong genetic control but these characters are not associated with phenotypic superiority in growth.
Somatic and genetic effects of incorporated strontium-90 and cesium-137 on Arabidopsis thaliana
Authors: Kamra O. P.
Published: September 2008

Somatic and genetic effects of incorporated strontium-90 and cesium-137 in the small crucifer Arabidopsis thaliana, race Estland, were studied. The uptake and distribution of the radionuclides in the treated plants (M1) and their progeny (M2) were determined and the approximate radiation dose received was calculated.A significant increase in plant height and acceleration of floral initiation in the M1 plants was observed. This was most likely a radiation effect rather than an ionic (or chemical) effect. The early flowering was consistently observed in several subsequent tests with acute gamma-ray seed treatment at 0.3 krads or 3 krads. The early floral initiation was not maintained in the M2 progeny despite measurable quantities of radionuclides transferred through the M1 seed to M2 progeny, exposing the latter to low level chronic beta-ray exposure.The M2 from 90Sr- and 137Cs-treated plants exhibited gross physiological changes (loss of apical dominance, dwarfism, gigantism, fasciation, etc.) and heritable mutations which persisted in the M3.
A compound from onions inhibitory to Pyrenochaeta terrestris
Authors: Pfleger F. L. , Vaughan E. K.
Published: September 2008

In vitro tests showed that mycelial growth of Pyrenochaeta terrestris (Hansen) Gorenz, Walker and Larson was inhibited by extracts from noninfected roots and bulbs of the pink-root-resistant onion cultivar Nebuka, and to a lesser extent by extracts from the moderately susceptible and highly susceptible Yellow Sweet Spanish and Southport White Globe, respectively. The active principle was shown to be fungistatic rather than fungicidal. Inhibitory activity of root and bulb extracts from Nebuka was eluted as a single peak from a Bio-Gel P-10 column. The inhibitory compound had an Rf value of 0.44 on silica gel plates developed in a mixture of methyl ethyl ketone, pyridine, water, and glacial acetic acid (70:15:15:2). The compound reacted positively to ninhydrin, ammoniacal silver nitrate, bisdiazotized benzidine, and diazotized sulfanilic acid. The inhibitory effects of the compound were lost by heating or by exposure to extreme acid or base conditions. The inhibitory compound was without effect when column fractions were diluted 1:30 or more. Quantitative estimation of total phenols in extracts from onion cultivars ranging from highly resistant to completely susceptible showed that resistant cultivars contained about 35% more total phenols than did susceptible ones.
Ecology of Cladonia lichens. I. Preliminary assessment of the ecology of terricolous lichen–moss communities in Ontario and Wisconsin
Authors: Lechowicz Martin J. , Adams Michael S.
Published: September 2008

Principal component and Bray and Curtis ordination techniques were used to explore the ecology of lichen–moss ground-layer communities in Ontario and Wisconsin. The Ontario data included thirty-nine 100-m2 stands from a large geographic region; lichen and moss relations along macroscale environmental and successional gradients were considered. Species relations along gradients of moisture and exposure were recognized. The Wisconsin data included one hundred sixty-six 0.5-m2 quadrats from a single site in the Wisconsin Pine Barrens; species relations along microscale environmental gradients were examined. Gradients related to moisture, light, and temperature regimes were recognized. The ordinations provided a graphic display of the ground-layer lichen–moss community ecology and offered a basis for further work on the comparative autoecology of various Cladonia lichens. Cladonia mitis, C. rangiferina, and C. uncialis, the subject of a subsequent paper in this series, were found to be similar in the macroscale but separated in the microscale ordinations.
A comparative study of gametophyte development of the diploid and tetraploid races of Polypodium virginianum
Authors: Kott L. S. , Peterson R. L.
Published: September 2008

Three different cytotypes, diploid, triploid, and tetraploid, occur within the fern species Polypodium virginianum or rock polypody. Previous studies have shown morphological differences in the sporophyte and this study was undertaken to determine the distinctiveness of the gametophyte of these cytotypes. The cytotypes differ in several developmental features: percentage of viable spores produced, time required for germination to take place, and time required for the gametophytes to reach sexual maturity. Of the three cytotypes, the tetraploid had a higher germination rate and considerably faster rate of development than either the diploid or triploid. The triploid showed a high percentage of aborted spores and a slow and irregular development of the gametophyte.
Rooting structures of the Carboniferous medullosan pteridosperms
Authors: Rothwell G. W. , Whiteside K. L.
Published: September 2008

The discovery of several distinctive root fragments in carbonate petrifaction material from Illinois provides the basis for the investigation of a Middle Pennsylvanian medullosan rooting system. Specimens range from minute rootlets with incomplete primary development, to large axes over 2 cm in diameter with extensive secondary development. The axes are characterized by an exarch actinostele with up to five protoxylem points. The pericycle of small rootlets is surrounded by endodermis, parenchymatous cortex, and epidermis. More mature specimens exhibit periderm at the outer margin of the pericycle, and in the largest specimens the periderm forms the outermost tissue zone. Secondary xylem is extensively developed in large specimens, and completely surrounds the primary wood. The newly discovered specimens are compared with previously described medullosan roots, and possible affinities with the Middle Pennsylvanian species of Medullosa and Sutcliffia are discussed.
Primary production and life history of Carex lacustris
Authors: Bernard John M. , Macdonald Jr. James G.
Published: September 2008

Seasonal changes in aboveground and belowground standing crop and primary production in a Carex lacustris wetland were determined and related to the basic life history of this species. There was a seasonal minimum of 180 g/m2 green material aboveground frozen in the ice in winter and a maximum of 1037 g/m2 in summer (early August). Seasonal aboveground production based on quadrat data and based on the difference between maximum and minimum standing crop is estimated to be 857 g/m2 per year, maximum daily production 15 g/m2 per day. A second estimate, also based on quadrat data but taking into account the very high shoot mortality during the growing season, was determined. Seasonal aboveground production then is 1580 g/m2 per year, maximum daily production is 20.3 g/m2 per day. Belowground standing crop was 387 g/m2 in winter but then declined to an average summer low of 226 g/m2. Belowground standing crop increased during autumn and, by October 7, a value equal to the previous winter's value was reached. Shoots of this species live for 1 year or less, emerging in autumn, overwintering, and then dying sometime during the next summer.
A cytochemical and ultrastructural study of the echinate cytoplasmic inclusion in Nitella flexilis (Characeae)
Authors: Silverberg B. A. , Sawa T.
Published: September 2008

Echinate bodies most commonly 20–40 micrometers (μm) in diameter are conspicuous inclusions carried with the cyclosis in the internode cells of some charophytes. Those in Nitella flexilis were investigated with light and electron microscopes. The chemical nature of the inclusion identified through various cytochemical techniques in the present study disagrees with the generally held belief that the echinate body is almost entirely composed of proteins. Microchemical tests have convincingly revealed the presence of tannin. The inclusion's close spatial association to endoplasmic reticula and to vesicles apparently derived from the Golgi apparatus and the cytochemical demonstration of acid phosphatase and thiamine pyrophosphatase activities in the matrix of the inclusion suggest that both cell organelles are actively involved in the development of this bizarre body with unknown function.
Springtime dispersal patterns of Monilinia laxa conidia in apricot, peach, prune, and almond trees
Authors: Corbin J. B. , Ogawa J. M.
Published: September 2008

Numbers of airborne Monilinia laxa conidia were related to the maturity of the sporodochia, the nature of the host structure bearing them, and the presence or absence of rain or fog. Hirst spore traps collected more airborne conidia during rains and on rainy days than on dry days among prunaceous hosts during the spring of 1966 and 1967. Numbers of conidia were greatest (6440 m−3 h−1) in the first 3–4 h of rain, while in dry periods, numbers were greatest (1200 m−3 h−1) when ambient humidity was lowest and temperature and wind speeds were highest. Fruit mummies, twig cankers, limb cankers, pedicels, and peduncles all bore sporodochia. Rains washed off successive crops of conidia, and with 52 800 conidia cm−2 were collected directly below a sporulating peach fruit mummy. The significance of these dispersal periods in disease development and control is discussed.
The mechanism of de novo synthesis of fructooligosaccharides in leaf disks of certain Asteraceae. III.
Authors: Chandorkar K. R. , Collins F. W.
Published: September 2008

14C-tracer experiments revealed that both endogenous and exogenous substrate was incorporated in the fructosans synthesized in leaf disks during incubation on phosphate-buffered sugar media. At least some of the endogenous substrate was derived from a source which was insoluble in 80% ethanol at the start of the incubation period. Endogenous and exogenous substrates were distributed in the fructosans in a pattern which was qualitatively similar regardless of the type of sugar supplied exogenously. A complex relationship was exhibited between the specific activity of various fructosan oligomers, expressed on a gram basis, and their chain length. However, expressed on a molar basis, the specific activity of the fructosyl tail portion of each homolog appeared to be linearly related to the number of hexosyl residues that it contained. Such a relationship suggests that enzymes similar to the Jerusalem artichoke tuber transfructosylases are present in leaf disk tissue after 72 h incubation and indeed may function in the de novo synthesis of fructosans in vivo.
The influence of growth conditions and leaf maturity in relation to the chlorogenic acid stimulation of glycollate oxidase from tobacco leaves
Authors: De Jong Donald W.
Published: September 2008

Glycollate oxidase (glycollate: oxygen oxidoreductase EC. 1.1.3.1) levels in tobacco leaves from plants grown under three different photoperiods and three different temperature regimes were compared. Leaf extracts obtained from mature plants grown at moderate temperatures (25–20C; day/night) and with intermediate day lengths (10 h) showed highest activity. In contrast, peroxidase (EC. 1.11.1.7) was highest in extracts from plants grown at low temperatures and short days while chlorogenic acid oxidase (EC. 1.10.3.1) was highest in leaf extracts from plants grown at high temperatures. Other investigations revealed that old leaves contained consistently lower glycollate oxidase levels than young leaves from the same plant. The addition of chlorogenic acid to the assay medium tended to equalize differences in enzyme activity. Photosynthetic efficiency as determined by O2 evolution (Hill reaction) and photophosphorylation in isolated chloroplasts improved with leaf maturity but this development did not appear to be a direct consequence of low photorespiratory activity. Measurements of the conversion of glycollate-1-14C to 14CO2 by leaf disks under light or dark conditions indicated that chlorogenic acid affects glycollate metabolism in vivo. It is postulated that chlorogenic acid moderates photorespiration by interacting with glycollate oxidase.
Floral development of Butomus umbellatus
Authors: Singh V. , Sattler R.
Published: September 2008

The primordia of the floral appendages appear in acropetal succession and develop in the order in which they appear. The primordia of each whorl of appendages are formed in a rapid sequence. After the inception of outer tepal primordia, the floral apex becomes triangular. On each angle, one inner tepal primordium together with the primordia of a pair of outer stamens and an inner stamen is formed. The triangularity of the floral apex might be interpreted as an indication of the formation of petal–stamen (CA) primordia as reported for Alisma and Hydrocleis. If this is the case, the primary pattern of organogenesis of the Butomus flower is trimerous and tetracyclic, i.e. one whorl of outer tepals, one complex of inner tepals and stamens, and two whorls of pistils. The floral apices have a two-layered tunica surrounding a central corpus. The initiating divisions in the formation of all floral appendages occur in the second tunica layer. In the case of stamen primordia, the outer corpus is also involved. Procambial development is acropetal. One procambial strand differentiates into each floral appendage shortly after its inception. Additional procambial strands are formed in the pedicel and the perianth and gynoecium. The relationships of Butomus to the Magnoliidae are discussed.
A new plicate Cyathus from India
Authors: Brodie Harold J.
Published: September 2008

A pale-colored, strongly plicate species of Cyathus (Nidulariaceae), at present known only from Mysore (India), is described as C. ellipsoideus sp. nov. It is the only species known to possess peridioles and basidiospores both of which are ellipsoidal in outline. Cyathus ellipsoideus bears close relationship to C. berkeleyanus and C. bulleri but has much larger spores than either.
Esterase isozyme patterns in Glycine max exposed to gamma radiation
Authors: Ferrer-Monge José A.
Published: September 2008

The esterase isozyme patterns for irradiated and non-irradiated soybean seed and seedlings were determined by starch gel electrophoresis. Patterns were determined for cotyledons, hypocotyl, epicotyl, first pair of leaves, and roots. Two different esterase systems, E1 and E2, were detected by using appropriate substrates. E1 produces three anodic bands with both α- and β-naphthyl acetate. E2 acts only on α-naphthyl acetate producing three cathodic bands. Radiation did not change the patterns. Results indicate that esterase isozymes are more abundant in the aerial than in the underground portion of developing seedlings.
Bud development in western hemlock. II. Initiation and early development of pollen cones and seed cones
Authors: Owens John N. , Molder Marje
Published: September 2008

Seed cones in Tsuga heterophylla (Raf.) Sarg. are found at the tips of distal lateral branches and form as a result of the transition of a previously vegetative apex. Pollen cones may be formed similarly and are then found at the tips of less-vigorous proximal branches but more commonly they develop from newly initiated axillary buds on short proximal shoots. In all cases, apices undergo transition to the reproductive state after a period of bud-scale initiation. Some apices initiate many bud scales, then either initiate leaves or undergo transition to a seed-cone apex in July. Other apices initiate fewer bud scales, then late in June undergo transition to a pollen-cone apex. Transition to a reproductive apex is marked by an increase in mitotic activity and apical size and loss of the vegetative pattern of zonation. Zonation reappears during the slower period of late bract and microsporophyll initiation but is not as prominent as it was in vegetative apices. In seed-cone buds, all bracts, ovuliferous scales, and megaspore mother cells are formed before dormancy. In pollen-cone buds all microsporophylls and microsporangia are initiated before dormancy and pollen mother cells begin meiosis and remain in the diffuse diplotene stage during dormancy. Pollen- and seed-cone buds become dormant in December. The time of cone initiation and sexuality of cones may be influenced by day length. The pattern of reproduction in western hemlock is compared in some respects with that of other conifers.
Meiosis in Coprinus. V. The role of light on basidiocarp initiation, mitosis, and hymenium differentiation in Coprinus lagopus
Authors: Lu Benjamin C.
Published: September 2008

Primordial bud formation in Coprinus lagopus is strictly light dependent, but only [Formula: see text]exposure to light is required. However, continued exposure to light is mandatory for further development and hymenium differentiation into a mature basidiocarp. Without light, the stipe of the primordial bud elongates as if the basidiocarp is maturing and the primordial bud eventually aborts. The optimum light intensity is less than 1 ft-c at a wavelength of 410–450 nm. It is possible that cap and stipe are initiated by the same stimulus, but further development of each is under different controls. The former is light dependent whereas the latter is not.The primordial bud development was studied at daily intervals for 3 days until meiosis started and their structural differentiations were studied by paraffin section and squash preparations. The cap of the primordial bud has three zones: the veil, the hymenium, and the stipe. The veil cells are large and multinucleate and lack clamp connections. The stipe includes a central column of dikaryotic hyphae and a cortex of giant multinucleate cells. The hymenium contains only dikaryotic hyphae, which later develop into basidia, cystidia, and medullar cells. The gill development is started by structural organization of dikaryotic hyphae into dome-shaped ridges, which is followed by disintegration of cells surrounding these ridges to form gills. The gill expansion is also light dependent.When the primordial buds were exposed to light, there was a thrust of mitotic activity. Mitotic metaphase, anaphase, and telophase configurations were clearly demonstrated.
Ultrastructure of pollen of Opuntia polyacantha
Authors: Kozar Frank
Published: September 2008

Ultrastructure studies of the pollen grains of Opuntia polyacantha reveal an elaborately sculptured ektexine but no endexine. The mature pollen cytoplasm is non-vacuolated, and contains plastids, starch granules, lipids, endoplasmic reticulum (ER), and relatively few other recognizable structures. Membranes and inclusions taken to be plasmalemmasomes were observed in the intine. Invaginations of the plasma membrane were also observed.
Net assimilation in long and short shoot leaves of Ginkgo biloba
Authors: Hoddinott John , van Zinderen Barker Jr. Eduard M.
Published: September 2008

The net assimilation capacity of long and short shoot leaves of Ginkgo biloba L. was measured and found to be similar in both groups of leaves. Anatomical investigation indicated that a previous report of differences in the palisade mesophylls of the two groups of leaves was unfounded, and this is reflected by the similarities in their net assimilation capabilities.
Distribution of vascular transfer cells in the culm nodes of bamboo
Authors: Zee S.-Y.
Published: September 2008

The distribution of xylem and phloem transfer cells in the node of bamboo has been described. Bundles supplying the leaf sheath contain numerous xylem transfer cells while those supplying the internode above the node and the axillary bud contain groups of phloem transfer cells which appear as swollen or knotted regions in the node. The significance of the presence of transfer cells in the nodes and the possible function of them are discussed.
Translocation of 14C-labeled assimilates in petioles and phloem loops of Heracleum lanatum
Authors: Hoddinott J. , Gorham Paul R.
Published: September 2008

The translocation of 14C-assimilates in intact petioles of Heracleum lanatum Michx. was compared with that in wounded petioles with isolated phloem loops. Wounding the petiole in isolating the loops interfered with normal translocation by stopping movement of 14C-assimilates in the isolated loop but not in the rest of the petiole. The isolated loop, however, took up and transported sucrose-6-6′ T, both acropetally and basipetally, from a solution in which a 1-cm length was bathed. A range of buffer and other solutions was used to bathe the petiole and loops during and after wounding, but translocation of 14C-assimilates in the loops could not be restored. The inability of isolated loops to translocate 14C-assimilates did not appear to be caused by desiccation, slime-plugging, or callosing. The mechanisms involved in transport of externally applied sucrose in isolated phloem loops appear to be different from those involved in the translocation of assimilates. Incision seemed to affect the latter in a region at some distance from the site of wounding.
The pattern of growth and translocation of photosynthate in a tundra moss, Polytrichum alpinum
Authors: Collins N. J. , Oechel W. C.
Published: September 2008

Green aboveground shoots of the moss Polytrichum alpinum Hedw., growing on the tundra at Point Barrow, Alaska, were exposed to 14CO2 in the field. Autoradiography and subsequent counting revealed preferential translocation of the labeled compounds into new belowground shoots arising from the extensive underground stem system. Within 24 h all stem systems extracted had been labeled throughout, a maximum distance of 7.5 cm being covered in this time, indicating minimum rates of 3.1 mm h−1.Increases in the number of new shoots aboveground throughout the season revealed the extent and importance of this translocation. Innate markers of seasonal growth enabled ages of the shoots at two sites to be determined and also the ages of shoots at production of gametangia in a third site where fruiting was common. The relative photosynthetic rates of the successive seasons' growth were also determined, and showed that by the 3rd year the photosynthetic capacity had dropped to about 40% of that in the youngest tissue on the same shoot.The patterns of growth and translocation of photosynthate in Polytrichum alpinum are discussed in relation to survival on the tunda.
Ecology of Cladonia lichens. II. Comparative physiological ecology of C. mitis, C. rangiferina, and C. uncialis
Authors: Lechowicz Martin J. , Adams Michael S.
Published: September 2008

The net CO2 exchange responses of Cladonia mitis, C. rangiferina, and C. uncialis from the Wisconsin Pine Barrens to irradiance, thallus temperature, and thallus relative water content were statistically compared for fall, spring, and summer. The absolute net photosynthetic rate of C. rangiferina exceeded that of C. uncialis under essentially all conditions and in all seasons; C. mitis's absolute net photosynthesis fluctuated with the seasons between these two contrasting species. Cladonia mitis showed significant intraspecific seasonal variation in net photosynthetic responses to temperature and irradiance. Cladonia rangiferina showed significant seasonal variation in dark respiratory response to temperature. Cladonia uncialis showed no significant intraspecific seasonal variation in net CO2 exchange responses. Significant interspecific differences in net CO2 exchange responses centered on the net photosynthetic responses to thallus temperature and relative water content.Despite its low net photosynthetic rates, C. uncialis is the most prevalent lichen in the Wisconsin Pine Barren ground-layer community. We attribute this not to broad physiological tolerance, but to its significantly slower drying rate. Lichens photosynthesize only when wetted. Cladonia uncialis photosynthesizes at generally lower rates than C. mitis or C. rangiferina, but it photosynthesizes longer under comparable environmental drying regimes. This and other aspects of the physiological ecology of the three species are discussed in relation to microdistribution and microhabitats within the Wisconsin Pine Barrens.
Protein synthesis and polyribosome stability upon desiccation of the aquatic moss Hygrohypnum luridum
Authors: Bewley J. Derek
Published: September 2008

Desiccation of the aquatic moss Hygrohypnum luridum was achieved quickly by placing pieces of the moss over silica gel, or more slowly in saturated atmospheres of high relative humidity. In each case there was an irreversible loss of polyribosomes on desiccation and the moss was unable to recommence protein synthesis on subsequent rehydration. The contrast between these results and those obtained previously with the terrestrial moss Tortula ruralis is outlined.
Ultrastructural and physiological changes in sporangia of Pseudopevonospova cubensis and Phytophthora infestans exposed to water stress
Authors: Cohen Yigal , Perl M. , Rotem J. , Eyal Helena , Cohen J.
Published: September 2008

Viability of sporangia of Pseudoperonospora cubensis and Phytophthora infestans was greatly reduced when sporangia were wetted for a period too short to ensure germination and then allowed to dry out (WDR treatment). No morphological changes were detected in WDR-treated sporangia by microscopic examinations, but when examined under electron microscope they exhibited partial or complete alterations of the mitochondrial inner membrane integrity, some deterioration of the plasmalemma, and extensive vacuolization.Water uptake was not affected but oxygen uptake was totally inhibited in WDR-treated sporangia and previously labeled sporangia exhibited increased leakage. No incorporation of 14C-leucine (into proteins) and 32P-orthophosphate (into nucleic acids) occurred as a result of the treatment. Adding various sugars, alcohols, and adenosine triphosphate (ATP) to the treated sporangia did not restore their viability.It was suggested that the water stress exerted by WDR treatment primarily caused a deterioration of the mitochondrial membrane integrity, which in turn probably led to the other phenomena listed above.
Chemosystematic studies in the genus Abies. I. Leaf and twig oil analysis of alpine and balsam firs
Authors: Hunt R. S. , von Rudloff E.
Published: September 2008

The volatile oils of the leaves and twigs of alpine fir, and western and eastern Canadian balsam fir were analyzed by gas–liquid chromatography. Many qualitative similarities were found and the within-tree and tree-to-tree variation of the quantitative terpene composition of the leaf oil was sufficiently small to permit a chemosystematic study. Abies lasiocarpa and A. balsamea may be differentiated by the relative amounts of β-pinene, 3-carene, β-phellandrene, trans-ocimene, piperitone, methyl thymol, and thymol. Consistent quantitative differences were also found between eastern and western A. balsamea, and the populations in the Lesser Slave Lake and Battle Lake regions of central Alberta gave intermediate terpene data, which suggests introgression between A. lasiocarpa and western A. balsamea. Thus a cline between A. lasiocarpa and A. balsamea, with western balsam fir populations as bridge, may have existed after the last glaciation. The alpine fir populations of southern Alberta, and eastern and central British Columbia gave uniform terpene data, but five trees sampled on Green Mountain, Vancouver Island, gave significantly different terpene data. These results were substantiated by morphological characters as well as twig oil analysis, but the latter two methods gave less consistent data than leaf oil analysis.
Etude préliminaire du phytoplancton du lac Saint-Louis, élargissement du fleuve Saint-Laurent près de Montréal, Québec
Authors: Alaerts-Smeesters Edith , Magnin Etienne
Published: September 2008

Seventeen samples were collected at regular intervals from September 1970 to December 1971 from four sites on lake St. Louis; these stations received their water either from the St. Lawrence River, the Ottawa River, or both. For each species and sample of the 178 phytoplankton entities found, the number of cells per liter was estimated. A general view of the distribution of plankton organisms at each station is given as well as the seasonal variation of the major systematic groups and the dominant species.
A new pleomorphic species of Humicola from Saskatchewan soil
Authors: Roxon J. E. , Jong S. C.
Published: September 2008

Humicola dimorpliospora is described as a new species. It is pleomorphic, producing dark, thick-walled, holoblastic conidia from portions of the vegetative hyphae as the principal spore type and hyaline, thin-walled, holoblastic conidia from sympodially proliferating conidiogenous cells as the secondary. The secondary spore type is characteristic of the genus Sporothrix. The type culture, ATCC 22422, was isolated from Saskatchewan soil, Canada, and is being preserved by freeze-drying and by storage in liquid nitrogen at – 196C. The range of temperature for growth of the fungus is 10 to 30C.
Differential response of 14 weed species to seven herbicides in two plant communities
Authors: Tomkins D. J. , Grant W. F.
Published: September 2008

The responses of 14 weed species to seven different herbicides were compared. The species included five monocots: Agropyron repens (L.) Beauv., Agrostis alba L., Carex gracilescens Mack., Phleum pratense L., and Poa pratensis L.; and nine dicots: Ambrosia artemisiifolia L., Aster cordifolius L., Fragaria virginiana Duchesne, Oxalis europaea Jord., Pastinaca sativa L., Solidago canadensis L., S. nemoralis Ait., Taraxacum officinale Weber, and Vicia cracca L. A principal component analysis revealed that species responses to four auxin herbicides ((2,4-dichlorophenoxy)acetic acid (2,4-D), picloram, picloram + 2,4-D, and 2,4-D + (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T)) were very similar, although picloram was more effective in eliminating Aster cordifolius, Fragaria virginiana, Solidago nemoralis, and Vicia cracca. Auxin response differed markedly between monocots and dicots, whereas life-form was important in determining the response of the species to paraquat, simazine, and diuron treatments. Response to herbicide treatment was similar in both pioneer and mature old-field communities. However, Phleum pratense and Poa pratensis were susceptible to all auxin treatments in the pioneer community but were resistant to the same treatments in mature fields.
The effect of salinity on a marine and a freshwater Ascomycete
Authors: Davidson Darwin E.
Published: September 2008

Lulworthia medusa, the marine isolate, grew significantly better in seawater than in freshwater medium. The growth of Ophiobolus graminis, the freshwater isolate, was reduced by one-half when grown in seawater. The growth of both species was similar in natural and artificial seawater. Neither species grew under anaerobic conditions.Warburg reactions indicate that the respiration of the freshwater species is reduced in seawater. The percentage reduction is about equal to the reduced growth in seawater, as compared to freshwater. The respirational rates of L. medusa in sea and freshwater were similar. Yet growth in seawater was much greater than in freshwater. Consequently, it is proposed that the respiratory energy produced in a freshwater environment is utilized for cellular functions other than biomass increase. In contrast to the marine isolate, the metabolic processes of O. graminis are severely affected by seawater. Ecological implications of the findings are discussed.
Ecology of Cladonia lichens. III. Comparison of C. caroliniana, endemic to southeastern North America, with three northern Cladonia species
Authors: Lechowicz Martin J. , Jordan William P. , Adams Michael S.
Published: September 2008

The net CO2 exchange responses of C. caroliniana in the fall to light, thallus temperature, and thallus relative water content were determined. Cladonia caroliniana responses were compared with three northern Cladonia: C. mitis, C. rangiferina, and C. uncialis. The eco-physiological characteristics of the four species provide some intuitive understanding of their biogeography and their microhabitat selection on the Wisconsin Pine Barrens. The temperature dependence of net photosynthesis of the four species correlates with their distributional relations. Cladonia caroliniana is physiologically adapted to higher temperatures than the three northern species. The limitations of this intuitive comparison are discussed and a quantitative alternative suggested.
Germination polymorphism in Rumex crispus. The effects of different storage conditions on germination responses of seeds collected from individual plants
Authors: Cavers P. B.
Published: September 2008

Seeds from six individual plants of Rumex crispus L. were stored under four contrasting conditions of temperature and relative humidity for 6 mo to 5 years. After storage, all viable seeds germinated under conditions of diurnally alternating light and temperature but there were significant interplant differences in the number of seeds that germinated in continuous darkness at constant or alternating temperatures. Seeds stored at room temperature had less precise germination requirements than those stored under frozen or chilled conditions. Viability was retained for 5 years under all storage conditions except for samples from three parent plants stored under chilling temperatures and variable humidity where 10 to 60% of the seeds had died. Germination of seeds was more rapid after storage.This experiment demonstrated that variable storage conditions can have a distinct effect on the germination patterns of seeds of R. crispus. Moreover, seeds from different plants responded in different ways to storage under the same conditions. Also, germination patterns under one germination regime were not predictable on the basis of results under another regime.
Occurrence of juvabione-related compounds in grand fir and Pacific silver fir infested by balsam woolly aphid
Authors: Puritch George S. , Nijholt W. W.
Published: September 2008

Two juvabione-related compounds, (+)-todomatuic acid and dehydrotodomatuic acid, were found in conjunction with certain balsam woolly aphid infested Abies grandis (Dougl.) Lindl. and Abies amabilis (Dougl.) Forbes but not with noninfested trees.The localized occurrence and variable distribution of these compounds within the wood of infested trees is discussed.
A preliminary treatment of the genus Podosordaria
Authors: Krug J. C. , Cain R. F.
Published: September 2008

Podosordaria Ellis et Holw. is used for those members of the Xylariaceae possessing stalkedor sessile stromata in the form of mammillate heads with erumpent ascocarps, containing whitish internal tissue, and covered with a brown to black or violaceous ectostroma; cylindrical to pyriform asci in which the ascospores may be biseriately arranged posteriorly; and one-celled, dark brown spores possessing elongated germ slits. The classical separation between Poronia Willd. ex Fr. and Podosordaria is maintained. An emended generic description and key are provided. Four new species and one new combination are described and illustrated—P. crinita on cow dung from the United States; P. ianthina on burro and goat dung from Mexico; P. phoenicea on zebra dung from Kenya; P. vinacea on burro dung from Mexico; and P. violacea (Sordaria violacea Ell. et Ev.) on cow, sheep, horse, and rabbit dung from Canada and the United States. One additional new combination, P. hircina (Poronia hircine Tai et Wei), is proposed. Brief comparative descriptions are included for those species not treated in detail. Short descriptive notes are provided for several taxa considered as doubtful representatives.
Fine structure of tannin accumulations in callus cultures of Pinus elliotti (slash pine)
Authors: Baur Paul S. , Walkinshaw Charles H.
Published: September 2008

Tannin accumulations in tissue culture cells of slash pine occurred in the smooth endoplasmic reticulum, in vesicles, and within cell vacuoles. Dense osmiophilic granules were observed also throughout the cytoplasm of many cells. Vacuolar deposits appeared as homogeneous spherules or as a froth-like material. Generalized degeneration of the cytoplasm and the organelles was observed in many of the cells synthesizing tannins. Accumulation of the tannin within the cell vacuoles did not necessarily result in cell degradation. Synthesis and deposition of tannin in slash pine cells closely resembles synthesis and storage of aromatic products in mammalian tissues.
Inclusions and wall deposits in cells of plants infected with oat necrotic mottle virus
Authors: Gill C. C.
Published: September 2008

Virus-like particles and two types of inclusion bodies were found in cells of leaves of oats, Avena sativa L., and Canada bluegrass, Poa compressa L., infected with oat necrotic mottle virus. The particles and inclusion bodies were seen in pale green tissue and in most samples of dark green tissue of mottled, mature oat leaves, but were seen only in the pale green tissue of immature leaves. There was also evidence of infection in oat roots.Tubules and (or) vesicles occurred between the cell wall and the plasmalemma (boundary formation) in many mesophyll cells of infected, mature bluegrass and oat leaves. Three types of abnormal deposits, localized, extensive, and fibrillar, also occurred between the wall and the plasmalemma in many of these cells. The extensive and fibrillar deposits were more common in bluegrass than in oats.
Effects of cadmium and zinc on ozone-induced phytotoxicity in cress and lettuce
Authors: Czuba M. , Ormrod D. P.
Published: September 2008

Cadmium or zinc solutions were applied to the foliage or roots of lettuce (Lactuca saliva L. cv. Grand Rapids) and cress (Lepidium sativum L. cv. Fine Curled) at concentrations of 100 parts per million (ppm) every 4th day for several weeks. Four weeks after sowing, plants were fumigated once with 30-35 parts per hundred million (pphm) ozone, for 6 h. Cress plants that had received soil application of cadmium showed markedly increased ozone-induced phytotoxicity in terms of visible leaf damage and pigment degradation; in lettuce, only pigment degradation was evident based on chlorophyll analysis. Soil application of zinc showed less ozone-induced phytotoxicity on cress and no pigment degradation in lettuce. Compared with soil application, foliar application of zinc or cadmium produced less effects on ozone phytotoxicity.
The extent of dark respiration in illuminated leaves and its control by ATP levels
Authors: Mangat B. S. , Levin W. B. , Bidwell R. G. S.
Published: September 2008

Bean leaves were supplied 14CO2 in light or darkness. After a brief flush, the total and specific radioactivity of respired CO2 were measured when leaves were kept in light or darkness either in air or in CO2-free air. Changes in the specific radioactivity of respired CO2 show that photorespiration and dark respiration are different processes having different and separate substrates. Little, if any, CO2 production by the process of photorespiration could be detected in darkness. The process of dark respiration was about 75% suppressed in light. Measurements of ATP levels in light or darkness and in air or CO2-free air suggest that dark respiration is controlled by photosynthetically produced ATP. This is supported by the fact that isolated intact spinach chloroplasts transfer most of their photosynthetically produced ATP to the medium.
New taxa of Laeticorticium (Aphyllophorales, Corticiaceae)
Authors: Larsen M. J. , Gilbertson R. L.
Published: September 2008

Three species of Laeticorticium are described as new: L. canfieldii from Arizona; L. durangensis from Mexico; and L. mississippiensis from Mississippi.
An electron microscope search for plastids in bleached Euglena gracilis and in Astasia longa
Authors: Kivic P. A. , Vesk Maret
Published: September 2008

Eighteen long-established strains of bleached Euglena gracilis (the products of several different bleaching techniques) and two culture-collection stocks of the naturally colorless Astasia longa were examined with electron microscope for the possible presence of plastids. Proplastid-like structures were observed in all but three of the bleached E. gracilis strains; none was seen in the A. longa stocks. None of the presumptive aplastidic strains appears capable of the extensive carotenoid synthesis seen in some of the other bleached E. gracilis stocks. There was no detectable chlorophyll(ide) in any of the several stocks examined, despite the presence of plastids.
Pseudoditrichum mirabile gen. et sp. nov. (Musci: Pseudoditrichaceae fam. nov.), a unique moss from Great Bear Lake, Northwest Territories
Authors: Steere William Campbell , Iwatsuki Zennoske
Published: September 2008

The name Pseudoditrichum mirabile Steere et Iwatsuki is proposed for a minute moss with leafy stem 1-3 mm high and seta 6 mm long; it was collected on calcareous silt near the Sloan River, Great Bear Lake, Northwest Territories, only a few miles south of the Arctic Circle. The gametophytic characters agree well with those of the Ditrichaceae, a relatively primitive family, but the peristome is clearly double, with the inner and outer teeth opposite, which thereby indicates a much more advanced phylogenetic position, perhaps at the evolutionary level of the Funariaceae. As the combination of gametophytic and sporophytic characteristics exhibited by this moss does not occur in any existing family of mosses, it is therefore deemed necessary to create the new family Pseudoditrichaceae for the new genus and species described here.