bluuebunny/crossref_metadata_2025 huggingface dataset:
Taxonomic note: redefinition of the genus Broomea and its relationship to Batioladinium gen. nov. (Cretaceous)
Authors: Brideaux Wayne W.
Published: September 2008

The type species of the genus Broomea Cookson and Eisenack possesses an intercalary archeopyle formed by loss of a single intercalary paraplate. Species with demonstrable apical archeopyles, formerly assigned to Broomea, are excluded by redefinition of that genus and placed in Batioladinium gen. nov. The taxonomic position of five other species previously assigned to Broomea cannot be resolved on the basis of current information. Transferred to the new genus are Batioladinium jaegeri (Alberti) comb, nov., designated herein as the type species; B. longicornutum (Alberti) comb. nov.; B. micropodum (Eisenack and Cookson) comb. nov.; and provisionally, B.? exiguum (Alberti) comb. nov. and B.? pelliferum (Alberti) comb. nov.
Histophysiologie des stigmates normaux et des formations stigmatoïdes chez Begonia tuberhybrida. I. Observations préliminaires
Authors: Lecocq M. , Dumas C.
Published: September 2008

Teratological floral parts corresponding to petals and stamens capped by stigmatoid lobes are found in double male flowers. These abnormal structures are quite comparable with normal stigmas in their morphology, histology, and histochemistry. Like the stigmas, the stigmatoid formations present a glandular activity and release an essentially hydrophobic exsudate. Fundamental differences between normal stigmas and stigmatoid formations cannot be demonstrated by the methods used.
Timing of infection and development of Gymnosporangium fuscum on Juniperus
Authors: Borno C. , Kamp B. J. van der
Published: September 2008

The germination of aeciospores of Gymnosporangium fuscum DC. on Juniperus spp. takes place in the fall soon after spore deposition. The first telial horns may appear the next spring, 6 months after infection instead of 18 months as previously believed.
Nematophagous fungi: a new Myzocytium
Authors: Barron G. L. , Percy J. G.
Published: September 2008

Myzocytium humicola is described as a new nematophagous fungus endoparasitic on Rhabditis. This species possesses unequally biflagellate zoospores. These do not attack the nematodes directly but encyst and produce adhesive buds that attach to the cuticle of passing nematodes. The oogonium is fertilized by the passage of the antheridial protoplasm through a pore in the contiguous wall. The resultant oospore has a thick, smooth or finely roughened wall.
The effect of soaking and drying seeds before planting on the germination and growth of Triticum vulgare under normal and saline conditions
Authors: Idris M. , Aslam M.
Published: September 2008

The soaking of wheat seed (Triticum vulgare L.) in water or CaCl2 solutions followed by air-drying before planting accelerated the germination but did not affect the final percentage germination and subsequent growth of the seedlings under normal conditions. However, under conditions of 0.5% NaCl salinity the soaking and drying of the seeds before planting stimulated the germination and growth of the seedlings. In no case were the presowing treatments more effective in improving the germination and root and shoot growth under 0.5% NaCl salinity than under normal condition. Under 0.5% NaCl salinity the seedlings grown from treated seeds had more extensive and deeper root systems than the seedlings grown from untreated seeds. Presowing soaking of the seed failed to improve the germination under increasing salinity of 1.0 and 1.5% NaCl.
Water relations parameters on single leaves obtained in a pressure bomb and some ecological interpretations
Authors: Cheung Y. N. S. , Tyree M. T. , Dainty J.
Published: September 2008

The physical implications of the various parameters obtained from a pressure-bomb study are explored and related to their possible ecological significance. Our analysis suggests that the original bulk osmotic pressure, the bulk osmotic pressure at incipient plasmolysis, and cell wall elasticity are closely associated with the extent to which a leaf can osmoregulate or conserve water within a certain range of water potential change in the environment and might therefore have certain adaptive value. The pressure–volume relation could be applied to predict changes in leaf water potential at various degrees of water loss in the field. The values of these various parameters were obtained from a pressure-bomb study on single leaves from a wide variety of species. The use of data from single leaves as compared with whole shoots is discussed.
The effect of Mg2+ on density of proplastids from the developing castor bean and the use of acetyl-CoA carboxylase activity for their cytochemical identification
Authors: Burden T. Scott , Canvin David T.
Published: September 2008

Proplastids from developing castor beans, Ricinus communis L., were isolated using velocity gradient centrifugation on sucrose gradients with superimposed gradients of Mg2+. Preparations were free of contamination by mitochondria and showed only slight contamination by microbodies. The use of acetyl-CoA carboxylase as a cytochemical marker for castor-bean proplastids was demonstrated.
Time of floral initiation in tobacco as a function of temperature and photoperiod
Authors: Thomas Judith F. , Anderson C. E. , Raper Jr. C. David , Downs R. J.
Published: September 2008

Nicotiana tabacum L. cv. Coker 319 has been found to be sensitive to changes both in temperature and photoperiod. Within a given time period fewer leaves are produced at low temperatures than at high temperatures. The classical day-neutral flowering response was not observed for this plant under six photoperiods of varying lengths. The results thus indicate that the plant may be more appropriately classified as being "preferentially ambiphotoperiodic," rather than strict "day-neutral." Preconditioning the seedlings with a long-day photoperiod produced plants that had higher total leaf numbers and flowered earlier than seedlings treated with a short-day photoperiod. The morphology of the vegetative and reproductive stem apex was similar to that reported for other species and cultivars of Nicotiana. Apical meristems were systematically ranked according to their progressive developmental stages encompassing vegetative, transition, and reproductive development.
Macrochemical reactions of species in the family Boletaceae
Authors: Harrison K. A. , Grund D. W.
Published: September 2008

Macrochemical reactions are reported on 15 species of Suillus, 3 of Fuscoboletinus, 2 of Gyroporus, and 1 species each of Boletellus, Boletinellus, Pulveroboletus, and Strobilomyces, together with a number of tests on species of Tylopilus and Boletus not available for an earlier paper. Three species of Suillus and three Boletus species are new records for Nova Scotia, and two of these are new for Canada. Also included are tests for a new species of Boletus to be described in another paper.Similarities in the macrochemical tests are used to divide 13 of the species of genus Suillus into two groups. Suillus luteus was selected as the type for group 1 and S. americanus for group 2. Two species did not belong to either group and were distinctly different from each other. Two species of Fuscoboletinus could be placed with group 2, but the third, F. paluster, differed widely. Boletus piperatus, which has been placed in Suillus by some authors, does not appear to be related on the strength of these tests. No attempt was made to group other species in Boletus or Tylopilus.
The transmission of global and photosynthetically active radiation within a dwarf apple orchard
Authors: Suckling P. W. , Davies J. A. , Proctor J. T. A.
Published: September 2008

Measurements of incoming global radiation, K↓, beneath a dwarf apple orchard canopy were made with a traversing sensor and a randomly located set of 10 stationary sensors. The location of the latter was changed once during the period of the experiment. On a daily basis, satisfactory agreement between the two sets of measurements was attained only for the second network location.Above-canopy and track measurements were used to calculate diurnal and daily values of canopy transmissivity, absorptivity, and reflectivity. Average values for the whole period were 0.53, 0.28, and 0.19. Analogous coefficients were obtained for photosynthetically active radiation (PAR). Extracanopy values of PAR were evaluated from PAR = 0.49 K↓ on 'bright' days (days with cloud cover less than [Formula: see text]) and PAR = 0.5 K↓ for cloudy days. These relationships were obtained by regression from sample measurements of PAR and K↓. Average PAR transmissivity, absorptivity, and reflectivity were evaluated as 0.42, 0.51, and 0.07.
An improved agar medium for isolating Phytophthora cactorum from soil
Authors: McIntosh D. L.
Published: September 2008

Adding sodium taurocholate to a chemically defined medium used for direct isolation of P. cactorum from soil increased numbers of propagules recovered and stimulated hyphal growth.
Effect of pH and sucrose concentration on conidium size and septation in four Bipolaris species
Authors: Harding Howard
Published: September 2008

Initial pH and sucrose concentration of the medium markedly affected sporulation and conidial characteristics in four Bipolaris species. Bipolaris sorokiniana and B. zeicola sporulated well at all pH levels; B. setariae and B. maydis produced relatively fewer conidia. Most isolates of B. sorokiniana sporulated well at all sucrose concentrations; sporulation by B. zeicola and B. maydis was less abundant, particularly at high sucrose levels. Only one of six isolates of B. setariae produced conidia at sucrose concentrations higher than 5 g/litre.In all four species conidium length and number of septa per conidium significantly decreased as the pH of the medium was increased, although some isolates of B. sorokiniana showed great variability. Conidium width was less markedly affected. Generally, in B. sorokiniana conidium length and number of septa decreased as the sucrose concentration was increased from 1 g/litre to 30 g/litre. In B. zeicola, conidia of maximum length and number of septa were produced on sucrose concentrations of 5 g/litre. Conidial characteristics of B. maydis were less markedly affected by increases in sucrose concentration.
Lipid phosphorus content and 33Pi incorporation in roots of alfalfa varieties during frost hardening
Authors: Grenier G. , Willemot C.
Published: September 2008

During controlled hardening of alfalfa, the lipid phosphorus content of the roots increased in the hardy variety Rambler while it decreased in the frost-sensitive variety Caliverde. Incorporation of 33Pi into the lipids decreased in both varieties during hardening but less in Rambler than in Caliverde. The proportion of the lipid radioactivity incorporated in phosphatidylcholine increased only in this phospholipid in both varieties. This increase was greater in Rambler than in Caliverde. The varietal differences in lipid phosphorus levels observed in hardened alfalfa seem therefore to be mainly the result of different rates of phospholipid degradation during hardening. However, the significant varietal difference in incorporation of 33Pi into lipids during hardening suggests that the higher de novo synthesis of phospholipids, mainly phosphatidylcholine, in the hardy variety also plays a role in the hardening process.
A systematic study of Salix section Cordatae in North America
Authors: Dorn Robert D.
Published: September 2008

Twelve North American species of the section Cordatae of the genus Salix (willows) were studied to clarify their taxonomy. The sections Adenophyllae (Commutatae) and Wolfianae are included here in section Cordatae. Characteristics of the epidermal cells and pollen grains were of no taxonomic value. Chromosome counts were obtained for 6 of the 12 species. One other species had been counted earlier. There are three diploid species, two tetraploids, and a hexaploid. One other species (?) has both diploid and tetraploid populations. Flavonoid chemistry of the leaves was the most important and constant characteristic. Each species has a consistent combination of compounds different from those of all other species of the section. Cytology, chemistry, morphology, and distribution were well correlated. Keys to pistillate material, synonymy, descriptions, distribution maps, and representative specimens are included. Three new species are described and one varietal transfer is made.
Measurement of CO2 exchange in lichens: a new method
Authors: Larson Douglas W. , Kershaw Kenneth A.
Published: September 2008

Results from studies of carbon dioxide assimilation in lichens cannot be tested independently against growth studies. To compensate for this, rapid, more rigorously controlled experimental systems must be used to sample a much wider range of environmental conditions.Methods in popular use are found to be inadequate in these respects.A new simple system is described which permits the response of net photosynthesis in lichens to be examined more efficiently than was previously possible.
Comparison of growth and extracellular polysaccharide of cotyledon cell suspension cultures of bush bean (Phaseolus vulgaris cv. Contender) grown in coconut-milk medium and synthetic medium
Authors: Mante S. , Boll W. G.
Published: September 2008

Growth and extracellular polysaccharide (EP) production by cotyledon suspension cultures of bush bean were compared in coconut-milk (CM) medium and synthetic medium. EP was produced at all stages of the culture cycle investigated. The same neutral sugars were present in the EP recovered from both media and the composition showed some changes during the culture cycle. Factors in coconut milk had relatively little effect on the neutral sugar composition of the EP.
Septum ultrastructure of Ostracoderma torrendii
Authors: Bronchart R. , Demoulin V.
Published: September 2008

Ostracoderma torrendii (Bres.) Hennebert (= Lycoperdellon t. (Bres.) Torrend) has electron-transparent septa that contain simple pores associated with Woronin bodies. This combination of characteristics, never reported outside the Ascomycetes, gives strong support to the disputed theory of the ascomycetous nature of this imperfect fungus.
Chemotaxonomic studies on hybrids of Dryopteris in eastern North America
Authors: Widén C.-J. , Britton D. M. , Wagner Jr. W. H. , Wagner F. S.
Published: September 2008

Sixty-nine specimens of Dryopteris were analyzed for phloroglucinols. Thirty-nine were referable to 9 sexual species and 30 were referable to 17 hybrid combinations. Ten hybrid combinations were analyzed for the first time. These are D. celsa × goldiana, D. celsa × clintoniana, D. assimilis × intermedia, D. campyloptera × intermedia, D. goldiana × intermedia, D. celsa × intermedia, D. assimilis × marginalis, D. campyloptera × marginalis, D. marginalis × spinulosa, and D. celsa × marginalis. Twenty-three naturally occurring hybrid taxa have now been analyzed and the use of the phloroglucinol system for systematics and evolutionary studies is assessed. Dryopteris marginalis and its hybrids have the most useful spectra of phloroglucinols for analysis. The hybrids in this group show the best additive spectra of the 23 hybrid taxa studied. Dryopteris marginalis, although a basic diploid species, is not considered to have given rise to derived alloploids.
Type studies of Massaria from the Wehmeyer Collection
Authors: Shoemaker R. A. , Leclair P. M.
Published: September 2008

The types of 65 names of species in Massaria and allied genera are accounted for, with illustrations made from slides of type collections supplemented by habit sketches and notes made by the late Dr. L. E. Wehmeyer. The following new combinations are made: Asteromassaria pulchra (Harkness), A. seriata (Cooke), Dendropleella stipitata (Fuckel), Hymenopleella occulta (Romell), Massaria lantanae (Otth), Pyrenula bataanensis (Rehm), Splanchnonema ampullaceum ([Pers.] Fries), Trematosphaeria berberidicola (Otth), and T. epileuca (Berk. & Curt.). Discussion is given on the types of the names and on the generic concepts of the genera Aglaospora, Massaria, Pleomassaria, Saccothecium, Spilobolus, and Splanchnonema.
Environmental limits of an endemic spruce, Picea breweriana
Authors: Waring R. H. , Emmingham W. H. , Running S. W.
Published: September 2008

Brewer spruce (Picea breweriana Wats.) persists as a relict in protected physiographic situations in southwestern Oregon and northwestern California, where a cool, montane, temperate zone inland from the Pacific Ocean is moderated in summer by maritime air masses. We attempted to uncover the reasons for its survival. We surveyed the species distribution and geologic and floristic associations, then studied effects of environment on growth and survival of two widely distributed species, Pseudotsuga menziesii (Mirb.) Franco and Abies magnifica Murr. var. shastensis Lemm., for a common basis for comparison. The survey included 130 plots along a 250-km transect. Brewer spruce was encountered along 70 km of the transect. Brewer spruce ranked well with other conifers in tolerance to soil moisture stress, cold temperatures, low light, and heavy, deep snow. Although sensitive to high evaporative demand, it appears to compete well with sparse vegetation in infertile or unbalanced soils developed from ultrabasic materials.
Genera coelomycetum. XI. Hyalotia, Hyalotiella, and Hyalotiopsis
Authors: Raj T. R. Nag
Published: September 2008

Hyalotia Guba, type species H. laurina (Mont.) Guba (≡ Pestalotia laurina Mont.), is reduced to synonymy with Bartalinia Tassi. Hyalotiella Papendorf and the type species Hyalotiella transvalensis Papendorf are redescribed. Hyalotiella orientalis sp. nov. is described as the second species of the genus. Some nomenclatural problems associated with the binomial Hyalotiopsis subramanianii, representing the monotypic genus Hyalotiopsis Punithalingam, are clarified. Hyalotia exilis (Tassi) Guba is redisposed in Gampsonema gen. nov. as Gampsonema exilis (Tassi) comb. nov. The status of other species of Hyalotia is discussed.
Two new soil-borne cleistothecial ascomycetes
Authors: Samson R. A. , Mouchacca J.
Published: September 2008

Leiothecium ellipsoideum Samson and Mouchacca, gen. et sp. nov., is characterized by dark, glabrous ascomata with thin pseudoparenchymatous walls and by ellipsoidal, reticulate, hyaline, one-celled ascospores. Rhexothecium globosum Samson and Mouchacca, gen. et sp. nov., has pseudoparenchymatous initials and is related to the genus Eremomyces Malloch and Cain, but it can be distinguished by ascomata with pseudoparenchymatous walls covered with some brown hyphae and by globose, pale yellow ascospores.
Induction of multiple buds and needles in tissue cultures of Picea glauca
Authors: Campbell Robert A. , Durzan Donald J.
Published: September 2008

Hypocotyl segments of white spruce seedlings, when placed with their basal end in a defined medium containing agar and 6-benzylaminopurine (BAP), formed up to 100 or more scale-like organs per segment. The organs did not arise from a preexisting apical meristem. The induction was inhibited by α-naphthaleneacetic acid (NAA). On medium containing 10−5 M BAP and no NAA, 69% of the explants formed multiple organs. When explants bearing the scale-like organs were transferred to media containing neither BAP nor NAA, the organs grew out into needles, and buds developed. Many of the buds developed into elongated shoots.
Ontogeny of the protophloem fibers and secondary xylem fibers within the stem of Coleus. II. An electron microscope study
Authors: Pizzolato Thompson Demetrio , Heimsch Charles
Published: September 2008

Ultrastructural changes within the protophloem fibers and secondary xylem fibers accompany their ontogeny in the Colens stem. The plasmalemma of both fibers portrays a gently undulating pattern against the wall before secondary wall formation. Commonly a narrow, hyaline region separates the primary wall and the plasmalemma. Fibrillar material arising from the plasmalemma is condensed in the wall. With the onset of secondary wall formation, undulation of the plasmalemma increases. Many microtubules traverse the membrane and are modified into extracytoplasmic microtubules. Vesicles produced by the dictyosomes and endoplasmic reticulum (ER) pass through or fuse with the plasmalemma. These processes abate after the initiation of the secondary wall. Cisternal, vesicular, and tubular forms of ER, the latter a rare form in wood fibers, fluctuate in amount during ontogeny. Mitochondria increase in number by fission and change in size and cristae volume. Microbodies are common in the youngest phloem fibers but are absent from the xylem initials. Microbodies arising as swellings of ER cisternae are numerous after secondary wall formation is underway in both fibers. Microfilaments are rare in wood fibers but are common in young phloem fibers. Spherosomes, which originate from ER cisternae, disappear during the initiation of the secondary wall. Phloem fiber plastids increase in number by either constriction or concentralization until shortly after the start of secondary wall formation. The plastids of the xylem fibers differ from those of the phloem fibers since the organelles contain phytoferritin and large starch grains initially, divide only by constriction, and do not form membrane-bound bodies.
The epicuticular waxes of glumes of Avena: a scanning electron microscopic study of the morphological patterns in all the species
Authors: Baum B. R. , Hadland V. E.
Published: September 2008

The epicuticular waxes of glumes of 357 samples, representing all the 27 species of the genus Avena. were examined under the scanning electron microscope. Three basic patterns were discerned, plates, knobs, and filaments, and each sample has been scored for the types found. A fourth category of unstructural pattern has also been scored. Variability within patterns was observed but not scored. It is concluded that epicuticular waxes on glumes in Avena cannot be used for identification of specimens to species except for various special cases when the choice to be made is between two or three alternatives. The main finding is that the degree of variability of the patterns is inversely proportional to the ploidy level. The hexaploid species consist almost exclusively of filaments: the other species have all the three basic patterns, with some species possessing a high proportion of only two patterns.
A new fossil plant of probable intermediate affinities (Trimerophyte–Progymnosperm)
Authors: Andrews Henry N. , Gensel Patricia G. , Kasper Andrew E.
Published: September 2008

Oocampsa catheta, new genus and species, comes from the early Middle Devonian of New Brunswick about ½ mi west of Dalhousie Junction. The plant is known from a central axis with spirally arranged first-and second-order branches; the latter dichotomize some what irregularly to produce ultimate fertile branchlets, located at varied distances along the second-order axes, so that the terminal, erect sporangia occur over a linear distance rather than in dense terminal clusters. The sporangia are ovoid with pointed apices and contain spores that are trilete, zonate, and ornamented with cones and spines. The spores are compared with dispersed spores known as Samarisporites or Grandispora.
The aggregation of wheat rhizoplane fibrils and the accumulation of soil-bound cations
Authors: Leppard Gary G. , Ramamoorthy S.
Published: September 2008

Some surface materials of roots can accumulate bound cations from the soil environment by contact exchange. This paper describes the physical relationships between rhizoplane fibril aggregates and other root surface structures in the zone of active cation uptake. Sheets and tufts of rhizoplane fibrils project from wheat roots and establish a discrete and intimate physical connection between root cell walls and the solid phase of the soil environment. These aggregates of fibrils may provide a direct channel for the movement of soil-bound cations to the surface of root cells. Consideration is given to a possible mechanism of extraction of soil-bound cations by rhizoplane fibrils and the transfer of these cations to the walls of cells actively engaged in cation uptake.
Xylaria polymorpha. II. Cytology of a form with typical robust stromata
Authors: Rogers Jack D.
Published: September 2008

The chromosome number of a collection Xylaria polymorpha from England appears to be n = 7, based on counts of pachytene bivalents and metaphase–anaphase chromosomes in ascospores. Ascospores are uninucleate when formed, becoming binucleate by a mitosis. One of the two nuclei is cut off into a cellular appendage. The appendage and its nucleus disintegrate in the ascus before ascospore maturation. Mature ascospores are unicellular and usually show no evidence of the former appendage.
Uptake of picloram by roots of alfalfa and barley
Authors: Morrison I. N. , Born W. H. Vanden
Published: September 2008

Uptake of [14C] picloram (4-amino-3,5,6-trichloropicolinic acid) from culture solution by alfalfa (Medicago saliva L.) and barley (Hordeum vulgare L.) seedlings was investigated to determine to what extent passive and (or) active mechanisms are involved in the uptake of the herbicide by roots of intact plants. The roots of both species had similar absorption patterns consisting of rapid initial uptake lasting 1 to 2 h, followed by continuing absorption at a markedly lower rate during the rest of a 12-h treatment period. Initial uptake both by roots and whole plants was not significantly reduced by 1.0 mM NaN3, whereas continuing absorption was depressed by this inhibitor. Q10 values were 1.4 for alfalfa and 1.0 for barley for the first 1–2 h of uptake, whereas for subsequent periods the values were consistently greater than 2.0. Evidently, uptake during the initial phase of entry is governed by passive processes, while continuing absorption is controlled, at least in part, by active mechanisms. Much of the picloram taken up by alfalfa and barley roots during a 4-h treatment period was released rapidly to unlabelled nutrient solution. Uptake by both species was decreased in the dark and enhanced in the presence of sucrose. The results of inhibitor studies suggest that picloram absorption by alfalfa plants is more dependent on a supply of metabolic energy than is uptake by barley plants. In most instances, total accumulation of picloram in 4 h was much greater in alfalfa plants than in barley plants of nearly equivalent mass. This difference may account for at least part of the difference in susceptibility of alfalfa (sensitive) and barley (tolerant) to the herbicide. Alfalfa roots always contained a much greater proportion of the total amount of picloram in the plant than did barley roots.
Histopathology of infection of bean with Pythium myriotylum compared with infection with other Pythium species
Authors: Dow Roberta L. , Lumsden Robert D.
Published: September 2008

Clusters of abundant appressoria formed from branching hyphae of mycelial inoculum of Pythium myriotylum on the surface of bean hypocotyls and roots. Pythium aphanidermatum usually produced single appressoria, but sometimes small clusters of appressoria. Pythium ultimum produced only single appressoria. Early pathogenesis of all species was characterized by rapid radial growth of hyphae in the epidermal cells, which was more rapid than in the cortex. These hyphae were constricted at the host cell walls. Invaded tissue and adjacent cells stained differently from healthy cells with all isolates. Aerial hyphae were produced from vesicles below the cuticle or within epidermal cells soon after infection was established. Safranin-staining materials were observed in the xylem, phloem, and tannin sacs. Zoospores of P. myriotylum and P. aphanidermatum germinated and produced long prepenetration hyphae, which branched and formed single appressoria. Oospores of P. myriotylum, P. aphanidermatum, and P. ultimum, after germination, produced branched hyphae and single appressoria. Penetration, rapid advance through epidermal cells, and ramification of cortical and vascular tissue were identical with those of mycelial inoculum. Sporangia of all three species formed intercellularly and intracellulary within 48 h and predominantly in the epidermis and upper cortex. Oogonia were produced intercellularly and intracellularly in 4 day s throughout the tissue, but mainly in the inner two thirds of the cortex. Sporangia of P. myriotylum and P. aphanidermatum in infected bean hypocotyls germinated within 3 h when flooded with tap water and produced zoospores within 6 h. When similar tissue was air-dried for 3 days or rapidly dried for 3 h. there was neither germination nor zoospore production.
Light-stimulated toxin production in Helminthosporium maydis, race T, cultures
Authors: Bhullar Balwant S. , Daly J. M.
Published: September 2008

Cultures of Helminthosporium maydis, race T, grown on modified Fries' medium under 1300 ft-c of continuous light produced at least 7 times more toxin than those grown in the dark. Thin-layer chromatography of the chloroform extracts of culture filtrates revealed that light has a general effect on metabolism of the fungus rather than a specific effect on toxin production. Light-grown cultures were found to be richer in chloroform-extractable metabolites including the toxin. The defined medium suggested by Karr et al. (5) was found to be unsuitable for high yields of toxin production.
Scanning electron microscopy of the septal pore apparatus of Rhizoctonia solani
Authors: Lisker N. , Katan J. , Henis Y.
Published: September 2008

The septal pore apparatus of Rhizoctonia solani was studied in hyphae of different ages by scanning electron microscopy. The formation of the septal pore apparatus begins with an annular swelling followed by the development of a dome-shaped perforated pore cap, which usually has three apertures. In older hyphae, the septal pore apparatus is absent, and the septal pore may be plugged. In some cases, four apertures are observed in the pore cap.
Sexual reproduction of mountain hemlock (Tsuga mertensiana)
Authors: Owens John N. , Molder Marje
Published: September 2008

Meiosis of pollen mother cells begins in October of the year in which cones are initiated. They reach pachytene then become dormant until the next March. Meiosis is complete and the winged pollen mature by mid-June. Meiosis of the megaspore mother cell occurs in May, forming a linear tetrad of megaspores. The female gametophyte undergoes free nuclear division at pollination in mid-June. No pollination drop is present; rather, the pollen adheres to the sticky, splayed edge of the micropyle, where it germinates and pollen tubes grow toward the nucellus. The nucellus elongates into the micropylar canal, forming a nucellar beak, which makes contact with the pollen tubes. Several pollen tubes penetrate the nucellus.At the time of fertilization early in August, each ovule contains two to four aichegonia each having two to four neck cells in one tier. Pollen tubes penetrate the neck cells and two male gametes are formed. The ventral canal cell breaks down and fusion occurs in the center of the archegonium. Four free nuclei form and migrate to the base of the archegonium. cell walls form, and a 16-celled proembryo develops. Both simple and cleavage polyembryony occur. Rosette cells divide but do not form complex embryos. The embryo and seed are mature in October and the cones dry and open during October and November. Mature cones averaged 70 seeds, of which 46% were filled.Reproduction in mountain hemlock (Tsuga mertensiana (Bong.) Carr.) is similar to that in other species of Tsuga except for the presence of winged pollen. Any attempt to place the species in the genus Picea or place it as a hybrid midway between Picea and Tsuga is unfounded based on all of the more-conservative reproductive and embryological characteristics.
Comparative changes in hardiness and lipid composition in two near-isogenic lines of wheat (spring and winter) grown at 2 °C and 24 °C
Authors: de Silva Nihal S. , Weinberger P. , Kates M. , de la Roche Ian A.
Published: September 2008

Changes in total lipids, fatty acids, and lipid-P contents of two near-isogenic lines of wheat seedlings of the parental spring (D) and mutant winter (C) genotypes of Triticum aestivum L. var. Triple Dirk were compared during germination and growth at 2 °C and 25 °C. Qualitative and quantitative changes of total lipids, phospholipids, and linoleic and linolenic acids were detected in both genotypes when grown at 2 °C for 2–5 weeks as compared with seedlings of equivalent morphological development grown at 25 °C. These differences may be associated with the freezing resistance that developed when both genotypes were germinated at 2 °C. During the period of growth at 2 °C from week 5 to week 6, which coincided with the completion of the vernalization response in the winter genotype, higher levels of phospholipids were found in the winter genotype than in the spring genotype. In this same period, the lipids in the seedlings of the winter genotype grown at 2 °C showed much larger increases in contents of linoleic and linolenic acids than the lipids of the spring genotype grown at the same temperature. These changes may be the result of a gene-linked temperature-sensitive mechanism controlling desaturation of fatty acids and could possibly be associated with the vernalization process.
Plastid development in a virescens barley mutant and chloroplast microtubules
Authors: Jhamb Swadesh , Zalik Saul
Published: September 2008

Development of plastids in a virescens mutant of ‘Gateway' barley was studied during greening of dark-grown seedlings and in seedlings grown in continuous light. Etioplasts of the mutant did not have a crystalline prolamellar body: however, prolamellar bodies were present in chloroplasts of the 4-day-old mutant when grown in continuous light. Upon illumination, the vesicles within etioplasts and young plastids of the mutant joined together to form grana lamellae and these were formed before the stroma lamellae. Formation of the lamellar system in the mutant was slow and the granal stacks were oriented irregularly rather than being all in the same direction within the plastid.The microtubules seen in the stroma of chloroplasts resembled cytoplasmic microtubules, but they were smaller in diameter and they were unlike them in their fixation properties and cold sensitivity. In the normal, microtubules were present in etioplasts and during formation of the lamellar system. However, in the mutant, they were observed only after formation of the lamellar system. From these findings, it was thought that the microtubules might perform a function in orienting the lamellar system of chloroplasts during their development.
Changes in mineral contents of cotyledons and young seedlings of woody angiosperms
Authors: Marshall P. E. , Kozlowski T. T.
Published: September 2008

Net changes in weights of P, K, Ca, Mg, B, Fe, Mn, Zn, Cu, Na, Al, Ba, Sr, and Cr in cotyledons and seedling axes of Acer rubrum L., Fraxinus pennsylvanica Marsh., and Robinia pseudoacacia L. were investigated during early seedling growth. Amounts of elements in embryonic cotyledons varied in the following order: Robinia pseudoacacia > Acer rubrum > Fraxinus pennsylvanica. Embryonic F. pennsylvanica cotyledons were very small and were embedded in endosperm. When seedlings were grown in the light with no inhibition of photosynthesis, mineral elements were either steadily translocated from cotyledons, accumulated in cotyledons, or initially accumulated in cotyledons and finally exported during cotyledon senescence. Differences depended on specific elements and species. The effects of growing seedlings in the dark or treating seedlings with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) to inhibit cotyledon photosynthesis were similar in that mineral translocation from cotyledons or accumulation in them was inhibited. Mineral element content in seedling axes increased as dry weights of seedlings increased.
Translocation of uranin in the symplasm of staminal hairs of Tradescantia
Authors: Tyree M. T. , Tammes P. M. L.
Published: September 2008

Translocation of uranin proceeds in the protoplasm of Tradescantia staminal hairs both in the acropetal and basipetal direction from a wound. A diffusion pattern is observed proportional to the square root of time. It is slower than physical diffusion in water. At any given time interval the number of cells traversed is almost equal whether transport is from the base or the tip. Consequently the distance from the base, where the cells are longer, is also longer. Translocation fits the calculation on a model in which the plasmodesmata in the interconnecting walls are almost occluded with solid obstructions or in which the plasmodesmata are under the influence of a more or less uniform negative charge. Resistance in the plasmodesmata seems to be the limiting factor in this case of symplasmic transport.
Endosperm abnormalities in Triticum–Secale combinations. I. × Triticosecale and its parental species
Authors: Kaltsikes P. J. , Roupakias D. G. , Thomas J. B.
Published: September 2008

The development of the fertilized embryo sac was investigated in four triticale lines, common wheat, durum wheat, and rye to ascertain whether a relationship exists between events taking place during the first 6–7 days of its life and kernel shrivelling. No differences were found with respect to embryo development either among triticale or between triticale and wheat lines. Generalized antipodal disintegration occurred earlier in rye and triticale with shrivelled seeds than in either wheat (common and durum) or triticale with full seeds; the difference was more pronounced between wheat and rye than among triticale lines. Triticale with shrivelled seeds and rye were also characterized by a higher number of aberrant endosperm nuclei and delayed generalized endosperm cellularization when compared with lines with plump kernels or with the wheats. No relationship could be established between the kind and position of aberrant nuclei and kernel shrivelling or frequency of aberrants and fertility. The rye parent is most likely responsible for the early degeneration of the antipodals, the formation of the aberrant endosperm nuclei, and the kernel shrivelling observed in triticale.
Amino acid transport systems of cultured soybean root cells
Authors: King J. , Hirji Rozina
Published: September 2008

The uptake of 1 μM14C-labelled arginine, glutamate, and alanine by cultured soybean (Glycine max L. cv. Mandarin) root cells was followed for periods up to 4 min at pH 5.5 in the presence of a 10 μM concentration of other amino compounds. From the degree of competition between 14C-labelled and unlabelled amino acids a number of uptake systems for basic, acidic, and neutral amino acids were identified, and a number of problems associated with amino acid transport in soybean cells were uncovered.
Ultrastructure of the dormant Agaricus bisporus spore
Authors: Greuter B. , Rast D.
Published: September 2008

A general view of the spore shows a thick three-layered wall, two nuclei, ribosomes, mitochondria, and microbodies, as well as prominent lipid droplets and glycogen granules. Vacuole-like structures can be detected next to the innermost wall layer, which plugs the conjunction with the sterigma. Special attention was given to the respective localization of mitochondria and microbodies.
Cladistic analysis of the diploid and hexaploid oats (Avena, Poaceae) using numerical techniques
Authors: Baum Bernard R.
Published: September 2008

Evolutionary relationships among Avena species were inferred by means of computer cladistic analysis. The method of Farris for computing Wagner networks was applied separately to the diploid and to the hexaploid species. The method of Camin and Sokal was applied to the diploid species only. A great number of networks were generated of which representatives are documented in this paper. After various roots have been chosen, a number of trees thus determined are proposed as hypotheses of cladistic relationships. Unit character consistencies were also computed to assess the degree of homoplasy of the characters in the different trees.
Fine structure of the macroconidia of Fusarium solani
Authors: Tewari J. P. , Skoropad W. P.
Published: September 2008

Ultrastructure of the macroconidia of Fusarium solani as visualized by transmission (ultrathin sectioning and freeze-etching) and scanning electron microscopy is described. The cell wall has four layers. The innermost layer is electron-lucid followed by an electron-dense layer. The next outer layer is spongy in appearance followed by a superficial layer consisting of fine filamentous processes. Freeze-etch replicas of conidia directly removed from the sporodochia and still suspended in the mucilaginous material (in which they are produced) frequently show the conidia connected by the superficial filamentous processes in the cell wall. This agglutination of the conidia is likely to increase the inoculum potential of this pathogen at the sites of infection. Structure of various membrane systems in the cells is described. The endoplasmic reticulum is fairly extensive and fenestrated. Thin sections of routinely fixed conidia show myelin figures. However, such structures were not seen in replicas of conidia that were freeze-etched without use of chemical fixation or cryoprotection.
An apparent relationship of soluble sugars with hardiness in winter wheat varieties
Authors: Green D. G. , Ratzlaff C. D.
Published: September 2008

Soluble carbohydrate patterns of two hardy winter wheat cultivars and two less hardy cultivars were compared during the cold-hardening process. Soluble carbohydrates increased in concentration as the seedlings developed and the cold-hardening process occurred. The largest soluble carbohydrate differentials between the hardy and less hardy winter wheat cultivars occurred in the sucrose and raffinose fractions. The accumulation of sucrose and raffinose in wheat growing at 7.2 °C–0.5 °C day–night was greater in the two less hardy winter wheat cultivars. An inverse relationship existed between soluble sugars and cold hardiness in the four cultivars studied.
The leaf anatomy of beech, Fagus grandifolia
Authors: Dengler Nancy G. , MacKay Lynette B.
Published: September 2008

Observations have been made on the anatomy of beech, Fagus grandifolia Ehrh., with an emphasis on quantitative features. All surface areas and volumes were determined by projecting 2-μm serial sections, measuring them with a map tracer, and multiplying cell perimeters by section thickness or by the trace–cut–weight method. The organization of tissues, including a complex reticulate venation, is typical of many dicotyledons. Of the minor veins, only the quinternaries and veinlets lack bundle sheath extensions and have wholly parenchymatous bundle sheaths, the cells of which are often oriented at right angles to the vein. There are 12.1 mm of vein per square millimetre of leaf surface area, and 10 μm of vein (the diameter of a mesophyll cell) serves about 21.5 mesophyll cells. The mean maximum distance over which water and solutes must move between vascular tissue and mesophyll is 55 μm. The mesophyll cell walls may provide the pathway through which the bulk of the water moves; the volume occupied by the mesophyll cell walls is 55.7 mm3 or 11% of total leaf volume. The evaporative surface of the mesophyll is 13.36 mm2/mm2 leaf surface area.
Two additive, independent genes for mycelial growth versus sporidial growth of haploid cultures of Ustilago hordei
Authors: Groth J. V.
Published: September 2008

Three distinct haploid colony phenotypes, (1) sporidial, containing no hyphae and smooth-surfaced; (2) intermediate, containing some hyphae and usually smooth-surfaced; and (3) mycelial, containing more hyphae, rough-surfaced, and rapidly spreading, were recognized in F1, haploid lines of Ustilago hordei (Pers.) Lagerh. derived from a cross of two intermediate lines, E3a and 14A. Crosses among all phenotypes and analysis of unordered progeny tetrads and random sporidial isolations revealed that two loci, one from each parental line, govern this trait. The loci are independent and their effects are additive. One locus, in line E3a, is linked to the mating-type locus.Tetrad sets from Tapke's 13 races were examined and in no case was segregation for this trait seen.
Accumulation of an adcrusting substance in the pigment strand of a diploid and a tetraploid wheat
Authors: Zee S.-Y.
Published: September 2008

The pattern of accumulation of the sudanophilic substance on the wall of the cells of the pigment strand of a diploid and a tetraploid wheat was followed by high-resolution light microscopy. The cells of the pigment strand of the 4n wheat tend to elaborate and accumulate more adcrusting substance in the cells of the pigment strand than the 2n wheat. The functional significance of the accumulation of the adcrusting substance in relation to the filling mechanism of the wheat grain is discussed.
The effect of heat shock on differentiation of germinating conidia of Trichoderma viride
Authors: Spiegel Sara , Henis Y. , Chet I. , Messer Glenda
Published: September 2008

Studies on the germination of Trichoderma viride spores indicate that they lose their resistance to heat at an early stage of germination. Whereas dormant conidia were resistant to 46 °C, the same treatment given 4 h after the onset of germination was lethal to the germinating spores. A milder thermal treatment (45 °C for 10 min) given during the first 2 h of incubation caused a delay both of swelling of conidia and appearance of germ tubes.Sensitivity of spores to heat was dependent on the temperature, duration of treatment, and incubation in a nutrient medium before application of the thermal treatment.Increase in oxygen uptake, rate of protein synthesis, and RNA synthesis were observed 2–3 h after the onset of germination. Ultrastructural changes were first observed after 4 h of germination. Application of the mild thermal treatment during the first 2 h of germination resulted in a delay in the observed increase in oxygen uptake, protein synthesis, swelling, and ultrastructural development, as well as emergence of germ tubes.
Morphology, development, and cytochemistry of the hyphae and sclerotia of species in the Rhizoctonia complex
Authors: Tu C. C. , Kimbrough James W.
Published: September 2008

A detailed comparison of the gross morphology of hyphae, monilioid cells, and sclerotial formation and structure of 17 isolates of species in seven genera of the Rhizoctonia complex were studied. Cytochemistry of both hyphal and sclerotial cells was also studied. Gross morphology of hyphae was similar in many of the isolates and was considered of limited taxonomic value. Sclerotial formation in species of Thanatephorus, Waitea, Aquathanatephorus, and possibly Ceratobasidium was of the monilioid cell type. That of Athelia was of the hyphal strand type. Although initially similar, mature sclerotia in each of the genera showed great diversity. Most sclerotia of Thanatephorus were constructed of loosely arranged monilioid cells. Those in Ceratobasidium developed a marginal rind; Aquathanatephorus, a pitted surface and hyphal mat; Waitea, a bilaminate condition with elongate marginal and globose medullary cells; and Athelia, a complex tetralaminate structure. Distribution and concentration of carbohydrates, proteins, and lipids differed in the various genera. The strong dextrinoid reaction of the cytoplasm of Thanatephorus and Aquathanatephorus, accompanied by higher total lipids in cell walls and septa, was of significance. Stronger reactions for cellulose were found in species of Ceratobasidium, while cellulose appeared more concentrated in sclerotial cells than in hyphal cells of Thanatephorus. Lipids were deposited more abundantly in sclerotial cells than in hyphal cells.
New microfungi on coastal Douglas fir
Authors: Funk A.
Published: September 2008

Three new species of ascomycetes and two coelomycetes are described from diseased Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) from coastal British Columbia, Canada, viz., Coccomyces pseudotsugae n. sp., Phragmoporthe pseudotsugae n. sp., and Botryosphaeria pseudotsugae n. sp.; Phomopsis portei n. sp. and Haplosporella sp. are associated with the latter two ascomycetes, respectively, and possibly represent their conidial states.