bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrastructural observations on guard cells of Vicia faba and Allium porrum
Authors: Allaway W. G. , Setterfield George
Published: September 2008

Stomata of Vicia faba and Allium porrum were examined in thin section with the electron microscope. Guard cells contained numerous mitochondria, few plastids, and relatively small vacuoles traversed by many strands of cytoplasm. Spherosomes were often observed but were variable in occurrence. Endoplasmic reticulum and dictyosomes were present, although not well developed. Scattered microtubules were present at the periphery of the cells. Microbodies were very rarely observed in guard cells and no plasmodesmata were ever seen in the guard cell walls. Plastids were small and irregular in outline in guard cells of both species. Guard cell plastids of V. faba contained abundant large starch granules. In both species thylakoids were few and grana were small in comparison with mesophyll plastids. The inner of the two bounding membranes of guard cell chloroplasts was extensively invaginated, forming a peripheral reticulum. This was not observed in mesophyll plastids of these species. Small groups of microtubule-like structures were often observed in V. faba guard cell plastids; microtubule-like structures were less frequent in A. porrum plastids, and were not in groups. The structures described are compared with those of other epidermal cells and mesophyll cells, and are discussed in relation to guard cell physiology.
The mode of action of helminthosporal. II. Effect on the permeability of plant cell membranes
Authors: White G. A. , Taniguchi E.
Published: September 2008

The phytotoxin, helminthosporal (H-al), can damage the permeability of plant cell membranes and it is suggested that this may be an important factor in the susceptibility or predisposition of cereal tissues to attack by Bipolaris sorokiniana, the fungus which produces the toxin. Helminthosporal was tested for its effect on the apparent free space (AFS) of barley roots and the efflux of betacyanin from red beet root tissue. Cell membrane disruption was indicated by an increase in the AFS of H-al-treated barley roots. The effect of H-al on the AFS of barley roots did not appear to be correlated with respiratory inhibition by the toxin since cyanide, azide, and 2,4-dinitrophenol failed to increase the AFS. Oxygen uptake by red beet root tissue was strongly inhibited by H-al at concentrations of 1.0 mM and 2.0 mM, and was accompanied by an immediate and large efflux of betacyanin. No correlation was found, however, between the extent of respiratory inhibition and the amount of pigment released. Helminthosporal reacts directly with both the plasmalemma and the tonoplast membranes of the beet root cell, exclusive of effects on respiration, since the loss of betacyanin was equally rapid under aerobic or anaerobic conditions. The integrity of the beet cell tonoplast membrane appeared to be unrelated to respiration and energy supply. Calcium ions, which act to stabilize membranes, partially alleviated the loss of pigment from red beet tissue exposed to n-propanol and H-al. Permeability change in the plant cell membrane may be as important in the mode of action of H-al as are the effects of the toxin on respiration and oxidative phosphorylation.
Cone infection by Peridermium harknessii
Authors: Byler J. W. , Platt W. D.
Published: September 2008

Infection of Pinus species by Peridermium harknessii characteristically occurs by invasion of young shoots. This paper presents evidence that the fungus also invades and infects young ovulate cones of Pinus muricata and P. contorta. The fungus subsequently grows down the cone peduncle and causes stem galls.
Carbon monoxide uptake and metabolism by leaves
Authors: Bidwell R. G. S. , Fraser D. E.
Published: September 2008

14CO was supplied to bean leaves in light or darkness at 200–360 ppm in air. In light, CO was converted mainly to sucrose and proteins. The distribution of 14C among products suggested that most of the absorbed CO was reduced and incorporated into serine and this was converted to sucrose. Some CO was oxidized to CO2, part of which may have been refixed as such in photosynthesis, but this was not the major pathway of light CO metabolism. In darkness, CO was absorbed nearly as fast as in light but was almost completely converted to CO2 and released.Light CO fixation by leaves of a number of species was measured using 1–10 ppm CO in air. Rates varied between 0 and 0.25 μmole/dm2 per hour. Rates were roughly proportional to CO concentration, but were unrelated to rates of photosynthesis. CO reduced or abolished CO2 fixation in some leaves. CO fixation by vegetation of intermediate CO-fixing capacity is calculated to be in the order of 12–120 kg/km2 ground per day, which approaches rates found for soil using much higher CO levels.
Chromosome numbers, meiotic behavior, and notes on some grasses from Central America and the West Indies
Authors: Davidse Gerrit , Pohl Richard W.
Published: September 2008

Chromosome numbers and meiotic behavior are reported for 99 collections of grasses representing 47 genera and 88 species. First chromosome counts are reported for the following 20 species: Aristida laxa, n = 22; Chloris ekmanii, n = 20; Chusquea scandens, n = 20; Danthonia domingensis, n = 18; Eragrostis hypnoides, n = 10; E. prolifera, n = 20; Festuca mirabilis, n = 14; Leptochloa scabra, n = 30; Manisuris ramosa, n = 18; Paspalum carinatnm, n = 40; P. distortum, n = 10; Pharus glaber, n = 12; Raddia sympodica, 2n = 22; Raddiella nana, n = 10; Schizachyrium gracile, n = 20; Setaria crus-ardeae, n = 18; Thrasya paspaloides, n = 20; Trachypogon ligularis, n = 10; Trichachne laxa, n = 18; Tristachya avenacea, n = 24. The count for Raddiella nana represents a first generic report. Counts that differ from previous counts for the same taxon are reported for these 11 species: Andropogon gerardii, n = 40; Aristida orizabensis, n = 22; Eragrostis trichocolea, n = 30; Ichnanthus nemoralis, n = 10; Microchloa kunthii, n = 22; Olyra latifolia, n = 22; Panicum cyanescens, n = 27; Paspalum caespitosum, n = 10; P. millegrana, n = 20, 30; Schizachyrium hirtiflorum, n = 20; Trachypogon montufari, n = 30.
Conidium ontogeny in hyphomycetes. The genera Torulomyces Delitsch and Monocillium Saksena
Authors: Hashmi M. H. , Kendrick Bryce , Morgan-Jones G.
Published: September 2008

Conidium ontogeny in Torulomyces lagena Delitsch and Monocillium indicum Saksena, the type species of Torulotnyces and Monocillium respectively, is analyzed by time-lapse photomicrography. The nuclear configurations occurring during conidiogenesis are also described. Since their development and karyology are essentially identical and their morphology closely similar, we consider them congeneric. Monocillium indicum is accordingly transferred to Torulomyces.
On the initiation of the inflorescence and floral organs in tomato (Lycopersicon esculentum)
Authors: Sawhney V. K. , Greyson R. I.
Published: September 2008

In view of conflicting interpretations of the initiation of the tomato inflorescence and the development of flowers we present a reinvestigation of this topic. The inflorescence apex arises from the terminal vegetative apex directly and the new vegetative apex from the bud axillary to the first leaf below the transition apex. The first flower is produced from the tip of the inflorescence apex and the second flower arises laterally to this flower. Sepals arise independently in a helical sequence as do petals and stamens. Carpel primordia initiate individually and subsequently fuse.
Evolution cyclique des chloroplastes dans une culture synchrone d'Euglena gracilis ‘Z.’ Etude stéréologique
Authors: Orcival-Lafont A. M. , Pineau B. , Ledoigt G. , Calvayrac R.
Published: September 2008

not available
Thin sections of plant cuticles demonstrating channels and wax platelets
Authors: Fisher D. A. , Bayer D. E.
Published: September 2008

Channels, possibly sites of wax precursor transport in vivo, and plates resembling wax were observed in thin sections of the cuticle of young leaves of Plantago major. The channels, which averaged 2.5 nm in diameter, were perpendicular to the surface and traversed the entire thickness of the cuticle. Channels appeared equally dense in the cuticles of both leaf surfaces and did not appear preferentially associated with guard cells or over anticlinal walls. Thus far channels have been found only in P. major.Wax platelets, which were parallel to the surface, were found in Ardisia crenata and similar appearing areas were found in P. major. The plates were thicker than the channels and when plates and channels were present together as in P. major the two sometimes merged.
A disease of conifer buds in western Canada associated with Dichomera gemmicola n. sp.
Authors: Funk A. , Sutton B. C.
Published: September 2008

A disease of conifer buds is described from western Canada. The associated fungus, a new species of the Sphaeropsidales, is described and named Dichomera gemmicola. Evidence of pathogenicity is based on isolation experiments.
A correlation of nuclear DNA content and thin-layer chromatographic patterns in resolving genome relationships in Avena
Authors: Iiyama Koji , Grant William F.
Published: September 2008

Relative amounts of nuclear deoxyribonucleic acid (DNA) from telophase root tip nuclei and thin-layer chromatographic patterns of alcohol-soluble compounds from dry leaves were determined for seven diploids: Avena clauda, A. pilosa, A. ventricosa, A. strigosa, A. hirtula, A. wiestii, A. longiglumis; four tetraploids: A. barbata, A. magna, A. abyssinica, A. vaviloviana; and four hexaploids: A. sterilis, A. fatua, A. byzantina, and A. sativa, in order to elucidate species relationships. Variation in nuclear DNA content was correlated with differences in genomic constitution; a few exceptions are considered to reflect chromosomal polymorphism. The average DNA value of the hexaploid species approximated the sum of the DNA value for A. magna and the theoretical value of the B genome. Chromatographic patterns showed distinct variations between species but little correlation between number of compounds and DNA content. Chromatographic patterns of hexaploids showed close similarity with those of diploids and tetraploids, except species with modified C genomes (A. clauda, A. pilosa, A. ventricosa) and A. longiglumis. It is considered that A. clauda, A. pilosa, A. ventricosa, and A. longiglumis did not participate in the evolution of polyploid taxa. From their chromatographic profiles, A. wiestii, A. abyssinica, A. vaviloviana, and A. byzantina are very closely related. Both A. magna and the AABB tetraploid species appear to share two genomes in common with the hexaploids. Hence, the genomic constitutions AADD and AABBDD have been proposed for A. magna and the hexaploids, respectively. Six compounds from ethanol leaf extracts of A. sativa were identified as three apigenins, luteolin, ferulic acid, and p-coumaric acid.
Floral morphology of the Amaryllidaceae. I. Subfamily Amaryllidioideae
Authors: Singh V.
Published: September 2008

The flowers of the subfamily Amaryllidioideae are similar to one another in that they are fragrant, showy, bisexual, and epigynous with two trimerous whorls of perianth and stamens each, and a compound gynoecium. A single vascular strand supplies the vascular system of both a perianth member and a stamen. It splits into three bundles, one median and two laterals. The former constitutes the vascular supply of a perianth member, while the latter, facing one another right and left, fuse to supply a stamen. This peculiar mode of branching of the vascular strand is considered to be associated with superposition of a stamen upon a perianth member. The corona of Narcissus which is supplied by inversely oriented vascular bundles, is regarded as an outgrowth from the perianth tube and those of Eucharis and Pancratium, which are non-vascular, to represent the stamen cup. Two series of vascular strands differentiate in all members investigated. While the inner series constitutes the placental supply, the strands of the outer series which vary in number in different genera, show various degrees of adnation among the traces occurring on the same radius. The nature of the inferior ovary has been discussed. The nectaries are considered to be of quite advanced type.
Differentiation between bicarbonate effect and pH effect on cation accumulation by barley roots
Authors: Falade J. A.
Published: September 2008

The effects of pH and bicarbonate on cation accumulation by barley roots have been separated. Bicarbonate stimulates but increasing pH inhibits, Na, K, Ca, and Fe absorption. Net enhancement is observed in the absorption of Na and K but depression in that of Fe at high pH in the presence of bicarbonate. The net enhancement is due to the HCO3− present in the bathing solution and the depression is due to pH.
The use of flavonoid components in the characterization of the genus Corydalis (Fumariaceae)
Authors: Fahselt Dianne
Published: September 2008

Flavonoids of Corydalis were compared with those of the closely related genus Dicentra in order to determine whether these compounds could provide diagnostic criteria for distinguishing between the two genera. No successful attributes were found in this suite of characters. This evidence, and data from other sources, points to an extremely close natural relationship between Corydalis and Dicentra and suggests that recognition of the two as separate genera represents an artificial situation.
Experimental bisection of Aquilegia floral buds cultured in vitro: II. Cytological changes following bisection
Authors: Jensen Lawrence C. W.
Published: September 2008

A previous paper in this series has reported on the effect of bisecting Aquilegia floral apices of different developmental stages by maintaining a continuous photographic record of living buds (Jensen 1971). The current paper is a preliminary light and electron microscope study of the cytological changes which occur following bisection of very young buds (sepal to petal stages). Bisected buds show a progressive increase in size of grains which are positive to periodic acid – Schiff stain up to 2 days after incision, followed by a progressive decrease in size up to 7 days after incision. These grains are probably starch as they were absent in sections treated with α-amylase and malt diastase. It is suggested that after bisection the buds are in a resting state for 1 to 2 days during which time sucrose is absorbed from the medium and stored as starch. As regeneration of a new apex proceeds, starch is digested and used by the cells of the growing bud.
Spore ornamentation in the Dryopteris spinulosa complex
Authors: Britton D. M.
Published: September 2008

The spores of five taxa of North American Dryopteris were studied with the scanning electron microscope. The taxa considered were two eastern diploids, D. intermedia (Muhl. ex Willd.) A. Gray and the eastern diploid of D. "dilatata”; two tetraploids, D. spinulosa (O. F. Muell.) Watt and D. campyloptera Clarkson; and one western diploid, D. assimilis S. Walker. All the taxa have spores with spines. Spine density and spine morphology are variable both within and between taxa and do not allow a clear identification of taxa using these characters alone. It is considered that all five taxa are closely related as evidenced by the similarities in their perine morphology as compared with species outside the complex.
A canker of western flowering dogwood caused by Sclerophoma ambigua n. sp.
Authors: Funk A. , Parker A. K.
Published: September 2008

Sclerophoma ambigua Funk and Parker, n. sp., is described from diseased flowering dogwood (Cornus nuttallii Audubon) in British Columbia, Canada. The canker disease is described and discussed; evidence of pathogenicity of the fungus is presented. The fungus is also associated with dieback of branch tips.
L'androcée synanthéré du Rechsteineria cardinalis (Gesnériacées). Une contribution au problème des fusions
Authors: Lamond Michel , Vieth Joachim
Published: September 2008

The syngenesious androecium of the Gesneriaceae results unquestionably from a postgenital union. Generally the stamens seem to remain entirely free from each other during the whole morphological differentiation process. In Rechsteineria cardinalis the contact between the anthers appears only after meiosis.In light microscopy the junction looks like an ordinary cohesion of the epidermis through the cuticles. Examination by electron microscopy reveals however a true discontinuity of the cuticles and also the complete absence of demarcation between the two united epidermises in the areas lacking cuticle. These two observations permit one to infer a real histological union or at least a metabolic reaction of the tissues united by synanthery.
Composition and structure of algal communities in a tributary stream of Lake Ontario
Authors: Moore J. W.
Published: September 2008

The composition and structure of epipelic and planktonic algal communities in Shelter Valley Creek, Ontario, was studied for 1 year. The overall assemblage consisted of 388 taxa of which 321 were Bacillariophyceae. On the sediments, seasonal succession and community structure was, with some exceptions, typical of a hard-water stream in the northern temperate zone. Taxa that occurred frequently throughout the year were Achnanthes minutissima Kütz., Cocconeis placentula var. euglypta (Ehr.) Cl., Gomphonema olivaceum var. balticum Cl., and Navicula tripunctata (O. F. Müller) Bory. The planktonic community was, for the most part, derived from the benthos. Herbivorous grazing by larval sea lamprey, Petromyzon marinus (Pisces: Cyclostomata) did not noticeably affect algal numbers in either the plankton or sediments.Sixty-six taxa are reported as new occurrences in southern Ontario.
A study of the carbohydrates in the cell walls of some species of the Entomophthorales
Authors: Hoddinott J. , Olsen O. A.
Published: September 2008

The cell walls of some members of the Entomophthorales were isolated and analyzed for their carbohydrate composition. Genera were found to differ qualitatively, while the species of Entomophthora differed only quantitatively. Among the differences, the glucose–mannose ratio emerged as the most useful taxonomic criterion. Differences in cell wall carbohydrate composition paralleled differences in lipid composition previously reported in species of Entomophthora. Because of the absence of chitosan, the Entomophthorales should not be grouped with the Mucorales on the basis of their cell wall carbohydrates, but should form a new group of chitin–glucan fungi.
Fine structure of percurrent basidial proliferations in Poria latemarginata
Authors: Setliff E. C. , MacDonald W. L. , Patton R. F.
Published: September 2008

Percurrent basidial proliferations in Poria latemarginata are described. After basidiospore discharge, the top of the basidium disintegrates and a new basidium develops inside the walls of the previous basidia. The basidium is then delimited at the base by a septal pore apparatus. As many as 11 basidia may develop from one point. Pairs of nuclei in basidia frequently were surrounded by a double membrane. The placement of P latemarginata in the genus Oxyporus will depend in part on whether or not the type specimen (Oxyporus connatus) has repeating basidia.
The ecological life cycle of the cedar glade endemic Leavenworthia exigua var. exigua
Authors: Baskin Jerry M. , Baskin Carol C.
Published: September 2008

Field, laboratory, and greenhouse studies were conducted on the ecological life cycle of the cedar glade endemic Leavenworthia exigua var. exigua over a 2-year period. Leavenworthia exigua var. exigua completes its life cycle (seed to seed) during autumn, winter, and early spring and is in the dormant seed stage from midspring to early autumn. This winter annual type of life cycle strategy is an adaptation of the species to its summer-arid, winter-wet habitat.Seeds of L. exigua var. exigua exhibit true dormancy at maturity and dispersal in spring. The seeds gradually afterripen during the spring–summer rest period. During the afterripening period the seeds pass from true (innate) dormancy to relative (conditional) dormancy then to a state of non-dormancy. After entering relative dormancy the temperature range for germination is widened through an increase of the maximum temperatures over which germination can occur. By early autumn most of the seeds in a population are completely non-dormant and can germinate over a wide range of temperatures, including those that normally occur in early autumn in its habitat. The exact time of germination in autumn is controlled by soil moisture. This type of afterripening pattern and germination control is an adaptation of the species to a hot, dry season.Although flower buds are formed during late autumn and early winter, the low temperatures and short photoperiods that accompany the winter season are not required for flower bud initiation and subsequent flowering. The main effect of low winter temperature on L. exigua var. exigua is that it slows growth and development and thus delays flowering and fruiting until early spring.
Origin and development of ascogenous hyphae and pseudoparaphyses in Sporormia australis
Authors: Blanchard Robert O.
Published: September 2008

Ascogenous hyphae and pseudoparaphyses of Sporormia australis Speg. originate independently at opposite poles in the locule of the ascocarp. Both arise from apparently undifferentiated pseudoparenchymatous cells. The pseudoparaphyses grow downward into the locule until they reach the basal area. At this level they intermingle with the ascogenous hyphae which grow out from the base of the locule. Although the two elements are closely associated, at no time do they exhibit cytoplasmic continuity.
Scanning electron microscopy of Cronartium spores
Authors: Grand Larry F. , Moore Royall T.
Published: September 2008

Aeciospores of C. conigenum, C. fusiforme, C. occidentale, C. quercuum, and C. strobilinum have surface features characterized by annulate projections and a well-developed smooth area. Aeciospores of C. appalachianun have annulate projections but lack a well-developed smooth area. Urediospores and teliospores of C. fusiforme and C. quercuum were indistinguishable from each other.
Studies on the possible relationships of microbodies and multivesicular bodies to oxalate, endopolygalacturonase, and cellulase (Cx) production by Sclerotinia sclerotiorum
Authors: Maxwell Douglas P. , Williams Paul H. , Maxwell Martha D.
Published: September 2008

The possible functional role of vesicles and crystal-containing microbodies in the production of oxalate, endopolygalacturonase, or cellulase by Sclerotinia sclerotiorum was investigated. The presence of multivesicular bodies in hyphal tips was not correlated with secretion or production of oxalate or these extracellular hydrolases. More crystal-containing microbodies were present in hyphal tips grown on media which supported greater extracellular enzyme production. No correlation existed between numbers of crystal-containing microbodies in hyphal tips and production of oxalate. Numerous membrane-bound vesicles (0.09–0.18 µm diam) were associated with tips grown on a D-glucose–Na succinate medium which supported high production of oxalate. The general ultrastructural organization of these hyphal tips was similar to that reported for other ascomycetes. Differences in numbers and distributions of organelles were observed between hyphal tips and older hyphae as well as between hyphal tips grown on the different carbon sources.
Cytotaxonomic studies of Draba species in Canada and Alaska: D. oligosperma and D. incerta
Authors: Mulligan Gerald A.
Published: September 2008

The cytotaxonomy of two closely related species of Draba, D. oligosperma Hooker (2n = 64) and D. incerta Payson (2n = 112), is discussed and a key is given. Both species are mainly confined to the mountains of western North America, although D. incerta is also disjunct nearly 3000 mi eastward to the tip of Gaspé County in Quebec. Draba oligosperma is an octoploid reproducing mostly by agamospermy and D. incerta is 14-ploid, producing seed by autogamy.
Nematophagous Hyphomycetes: Arthrobotrys anomala sp. nov.
Authors: Barron G. L. , Davidson J. G. N.
Published: September 2008

Arthrobotrys anomala is described as a new species. This species is distinctive in having extremely short conidiophores. Conidia are non-septate but may become once-septate following secession and before germination. Arthrobotrys anomala captures its prey by adhesive nets or branches.
Frequency and distribution of nuclear pores in Cucurbita maxima cotyledons as revealed by freeze-etching
Authors: Lott John N. A. , Larsen Per L. , Whittington Catherine M.
Published: September 2008

The frequency and distribution of nuclear pores in the cotyledon mesophyll cells of Cucurbita maxima were studied during germination. During the early stages of seed germination the nuclear envelope of the mesophyll cells was found to contain a distinctive pattern of nuclear pores. The nuclear pores were in short rows that divided the nuclear membrane into areas in which pores were absent. Mesophyll cells from a later stage of germination contained nuclear envelopes with significantly more nuclear pores per unit area. At the later stage of germination the distinctive pattern of nuclear pores was less readily distinguishable by visual observation of electron micrographs, but pattern analysis revealed that the pattern was still present.
Effects of sulfur nutrition on phytotoxicity and growth responses of bean plants to ozone
Authors: Adedipe N. O. , Hofstra G. , Ormrod D. P.
Published: September 2008

Phaseolus vulgaris L. cv. Blue Lake plants were grown in sand culture at three temperatures, and fed with nutrient solution containing 1.3 or 32 mg/liter sulfur (S). Plants were fumigated twice with ozone at 50 parts per hundred million (pphm) for 2 h.Intensity of phytotoxicity was markedly lower in plants grown at the high S rate. Ozone reduced chlorophyll content of plants grown in low S at 25/20 and 30/25°. With the high S treatment, however, ozone had no significant effect on chlorophyll content, particularly at the lower temperatures. Irrespective of S nutrition, ozone had no effect on total soluble carbohydrate content. Ozone effects on plant growth depended on plant part, growth temperature, and S nutrition.
Certain aspects of xylem differentiation in corn
Authors: Srivastava L. M. , Singh A. P.
Published: September 2008

Differentiation of vessel elements in corn is accompanied by marked changes in nearly all organelles except plastids. The young cells increase in volume and apparently synthesize new cytoplasmic protein. The initiation of wall thickening is accompanied by an aggregation of microtubules in specific locations and an increase in the number of mitochondria and dictyosomes. During the period of active wall deposition, the endoplasmic reticulum (ER) shows a highly elaborate form, harbors intralamellar tubules, and nearly blankets those parts of the wall which remain unthickened. Dictyosomes seem to produce at least two types of vesicles, one of which may serve as a carrier of lignin precursors. The final autolysis involves a progressive removal of vacuolar membranes, plastids, dictyosomes, vesicles associated with secretion of noncellulosic polysaccharides, microtubules, and finally plasmalemma, parts of cell wall, and cytoplasm. Mitochondria and ribosomes are degenerated. The ER probably plays an important role in this autolysis. The parenchyma cells associated with vessel elements are rich in mitochondria.
Reaction to common root rot of 14 Triticum species and the incidence of Bipolaris sorokiniana and Fusarium spp. in subcrown internode tissue
Authors: Harding Howard
Published: September 2008

There was wide variation in the common root rot reaction of lines and varieties of 14 Triticum species. The diploids, T. aegilopoides and T. monococcum, were the most resistant. Triticum timopheevi appeared to be more resistant than the other tetraploid species. The highest disease ratings were recorded in the hexaploid group with T. compactum being the most susceptible species. The range of reaction within the T. aestivum group was almost as wide as that over all Triticum species. Several old varieties appeared to have resistance at least equal to Manitou. Bipolaris sorokiniana was isolated from subcrown internodes of all lines and varieties tested. The incidence of B. sorokiniana in tetraploid and hexaploid lines was about twice that found in diploid lines. There were only poor correlations between disease ratings and numbers of internodes yielding B. sorokiniana.
Notes on Hyphomycetes. III. Redisposition of six species of Exosporium
Authors: Morgan-Jones G. , Kendrick Bryce
Published: September 2008

Six species of Exosporium Link ex Schlechtendal are considered to be unsatisfactorily classified in that genus and are, accordingly, redisposed elsewhere. One is placed in Cladosporium Link ex Fr., one in Curvularia Boedijn, one in Sporidesmium Link ex Fr., and three in Stigmina Sacc.
Purification and characterization of seed globulins from Brassica juncea, B. nigra, and B. hirta
Authors: MacKenzie S. L. , Blakely J. A.
Published: September 2008

Two globulins have been isolated from seeds of Brassica juncea, Brassica nigra, and Brassica hirta and the homogeneity of the preparations has been established by polyacrylamide gel electrophoresis and analytical ultracentrifugation. The respective proteins from the various species have similar physical properties but differ significantly in chemical composition. The relationship between the amino acid compositions of the proteins from seeds of the above species and also Brassica campestris is examined; the suggestion of hybridization of Brassica campestris and Brassica nigra to produce Brassica juncea is supported.
Structure of plastids of a variegated Betula pubescens mutant
Authors: Valanne Niina , Valanne Terho
Published: September 2008

The patterns of variegation in the leaves of Betula pubescens only become evident in the mature leaves. However, the young plastids are also abnormal and pigment analysis does not suggest that the deformation of the plastids is caused by carotenoid deficiency. In mature leaves the mutant plastids are badly deformed. Among the most typical defects are an amoeboid form and the budding of peripheral reticular parts from the mutant plastids. These budding parts can easily be mistaken for mitochondria, but a closer inspection reveals differences in their tubular structures. These buds should therefore only be considered a special type of abnormal plastid.
A new chemical race of Monarda fistulosa (Labiatae)
Authors: Marshall H. H. , Scora R. W.
Published: September 2008

A race, chemically distinct but morphologically similar to the widespread Monarda fistulosa L. var. menthaefolia (Graham) Fern., has been found to share the same habitat with the normal form in and around the Spruce Woods Forest Reserve in Manitoba.The foliage of the mutant form contained 0.7 to 1.1% oil on a fresh weight basis. This was about twice the quantity steam-distilled from the normal form. The oil from the mutant was 72 to 93% geraniol, previously unreported in Monarda. The mutant and normal forms cross readily, indicating no genetic isolating barriers have been established.
Species distribution in a mossy – dryas – sedge hummock tundra (Western Taimyr)
Authors: Beschel R. E. , Matveyeva N. V.
Published: September 2008

Type R principal components analyses of vascular plant, bryophyte, and lichen cover in a hummock tundra indicated the presence of more information in the pattern of the bryophytes than in the other plant groups. This was expressed as differences between the combined contributions of the first three components to the overall dispersions in the analyses of the three types of vegetation. For these values, which permit a general comparison of systems, the term "organization intensity" is introduced. The result was confirmed by the significance of correlations of the loadings of the species on the first and second components in replicate transects. The loadings of the bryophyte species on the first component correlate significantly with their position on the complex microgradient from hummock to hollow and give results that are less dependent on sampling methods than direct gradient analysis.
Studies on sunflower rust. X. Specialization of Puccinia helianthi on wild sunflowers in Texas
Authors: Hennessy C. M. R. , Sackston W. E.
Published: September 2008

Sunflower rust (Puccinia helianthi) was collected in Texas on wild Helianthus spp. believed to be ancestors of the cultivated sunflower (Helianthus annuus). Race 1, the least pathogenic on the standard "Canadian" differentials, was the most common. Races 1 and 2 predominated on H. annuus and H. debilis, race 2 on H. praecox, and race 4 on H. petiolaris. Most host species proved to be heterozygous for rust resistance; cross-infectivity tests between them were inconclusive. Puccinia helianthi shows a high degree of adaptive variability, which suggests that local specialization may be relatively unimportant.
Studies on sunflower rust. XI. Effect of temperature and light on germination and infection of sunflowers by Puccinia helianthi
Authors: Sood P. N. , Sackston W. E.
Published: September 2008

Urediospores of four races of Puccinia helianthi incubated on water agar for 6 h or on sunflower leaf discs for 16 h germinated equally well from 10 to 25 °C, but significantly less at 30° and least at 5 °C. Appressorium formation was highest at 10 to 25 °C, lower at 30 °C, and lowest at 5 °C for races 1 and 3; none occurred at 30 and 5° in races 2 and 4. The optimum for penetration by races 1 and 3 was 20 °C, for race 2, 15° to 20 °C, and for race 4, 20° to 25 °C. Results were the same on susceptible and resistant hosts.Germination percentage on water agar was reduced with increasing light intensity from 2200 to 17 600 lx during incubation for 6 h. Germination on sunflower leaf discs was reduced with increasing light intensity during incubation for 16 h. Appressorium formation and penetration were adversely affected by increasing light intensity.Inhibition by light was overcome during a subsequent dark period when inoculated leaf discs were exposed to various cycles of light and dark during a 16-h incubation period.
New taxa of Claytonia section Claytonia (Portulacaceae)
Authors: McNeill J.
Published: September 2008

A new species, Claytonia ogilviensis McNeill, is described from the Ogilvie Mountains, Yukon Territory, and a new geographical race of C. lanceolata, occurring on Vancouver Island and the Olympic Peninsula, is recognized as var. pacifica McNeill. A key is also provided to the Canadian representatives of Claytonia section Claytonia, to which both new taxa are referable.
Microdochium Syd.
Authors: Sutton B. C. , Pirozynski K. A. , Deighton F. C.
Published: September 2008

Microdochium Syd., type species M. phragmitis Syd., is redescribed and emended (a) for species with holoblastic conidiogenous cells and synchronously or sympodially produced conidia, and (b) to incorporate species, the conidia of which are prolonged at each end into appendages. Microdochium linariae T. Săvulescu is reduced to synonymy with Centrospora acerina (Hartig) Newhall. Microdochium caespitosum sp. nov. and M. griseum sp. nov. on dead leaves from Tanzania, and M. phyllanthi sp. nov. associated with leaf lesions on Phyllanthus discoideus from Sierra Leone are added to the genus. Comparisons with Idriella Nelson & Wilhelm and Arxiella Papendorf are made.
Population dynamics of Endogone spores in soil
Authors: Sutton John C. , Barron G. L.
Published: September 2008

A flotation–adhesion technique is described for the rapid recovery of Endogone spores using small (5–10 g) soil samples. The method proved 94–98% efficient in the recovery of spores from Ontario soils. Spore counts averaged 20–92 per gram with exceptional individual counts reaching 132. Effects of soil type, soil depth, and "host" plant on spore populations are discussed.
Effects of pretreatment temperature on carbon dioxide exchange in alfalfa
Authors: Pearson C. J. , Hunt L. A.
Published: September 2008

The temperature response curves for net carbon dioxide exchange are described for plants of cultivars (cvs.) Vernal and Moapa alfalfa (Medicago sativa L.) grown at day/night temperatures of 30/25C and 20/15C, an irradiance of 25 nE cm−2 s−1 (400–700 nm), and a day length of 15.5 h. Net carbon dioxide intake (NCI) of the tops decreased with increasing temperature from 20 mg dm−2 h−1 at 10C to 5 mg dm−2 h−1 at 40C. The nature of the NCI-temperature response curve was affected by pretreatment temperature, with NCI being lower at all temperatures except 10C after growth at 20/15C. Photorespiration, which reached its maximum value at a higher temperature (20–30C) than that required for maximum NCI, accounted for 22% of the gross carbon dioxide intake (net carbon dioxide exchange in an oxygen-free atmosphere) at 10C and 55% at 40C. Pretreatment affected the relationship between net carbon dioxide output (NCO) and temperature, with NCO being higher at 10C but lower at 30C after growth at 20/15C as compared to 30/25C.
The influence of carbon dioxide on protein synthesis in etiolated coleoptiles of Arena sativa
Authors: Bown A. W. , Lampman W. W.
Published: September 2008

Various concentrations of carbon dioxide have been used to assess the influence of carbon dioxide on protein metabolism in etiolated coleoptiles of Avena sativa. Increases in carbon dioxide concentration from 0% to 0.03% to 3% result in dramatic increases in both the total level of protein and the incorporation of radioactive leucine into protein. In addition an electrophoretic analysis indicates that as the carbon dioxide concentration is raised from 0% to 0.03% there is both an increased synthesis of most proteins plus a pronounced synthesis of one particular protein fraction. These results indicate that the normal atmospheric concentration of carbon dioxide has a profound influence on protein metabolism in Avena sativa coleoptiles and are discussed in connection with the well-documented phenomenon of carbon dioxide stimulated growth in etiolated plant tissues.
Interfertility and chromosomal uniformity in Cannabis
Authors: Small Ernest
Published: September 2008

Meiosis and pollen fertility were examined in hybrids representing combinations of 38 different populations of Cannabis. No irregularities were observed in meiosis, and pollen fertility was extremely high. It is concluded that there is little evidence for the development of sterility barriers in Cannabis, and accordingly there is no basis for recognizing taxonomic groupings on the criterion of breeding isolation.
The decline and recovery of photosynthesis of ponderosa pine seedlings subjected to low, but above freezing temperatures
Authors: Pharis R. P. , Hellmers H. , Schuurmans E.
Published: September 2008

The daily course of photosynthesis (Ps) was determined for ponderosa pine (Pinus ponderosa Laws.) seedlings before and after their transfer from 23° to 11° or 3 °C and vice versa. Apparent Ps at 11 °C was greater than at 23 °C for up to 17 days after transfer. The increase was of the same order of magnitude as the decrease noted in dark respiration (Rs). Apparent Ps at 3 °C was little affected for the first 3 days after transfer, but declined to about 70% of pretreatment rate by day 10. If dark Rs at 3 °C is taken into account, actual Ps declined to about 50% of pretreatment rate by day 10. After this, the decline in Ps, with time, proceeds slowly. Recovery of Ps after transfer from the lower temperatures to 23 °C was rapid only if the length of time at the low temperature did not exceed 1 day. Return of apparent Ps to pretreatment rates was accomplished by day 7 for plants subjected to 17 days of 11 °C. Recovery of apparent Ps for plants subjected to 4 or more days of 3 °C reached 80% by day 7, and 90% by day 23. Dark Rs of plants brought from 3° to 23 °C was increased appreciably at first, this increase being of the same order of magnitude as the decrease in apparent Ps. Dark Rs then decreased with time at 23 °C, this decrease being correlated with an increase in apparent Ps. It is concluded that the initial chilling "injury," if any, occasioned by very low, but above freezing temperature, does not involve the physical or metabolic apparatus of Ps, but rather is associated with the respiratory apparatus as evidenced by increased rates of dark Rs during recovery at higher temperatures.
Isolation of Hypoxylon mammatum from aspen stem sections
Authors: Anderson Darryl L. , French D. W.
Published: September 2008

Hypoxylon mammatum developed in noninoculated aspen stem sections which had the top ends dipped in paraffin and were then placed in moist sand, at 24C and 90% humidity for 3 months. The development of the fungus in the stem sections might have been due to the presence of ascospores or mycelium on or in the outer tissues of the stems.
Conidium ontogeny in Coelomycetes. IV. Percurrently proliferating phialides
Authors: Morgan-Jones G. , Raj T. R. Nag , Kendrick Bryce
Published: September 2008

Percurrently proliferating phialides, which superficially resemble annellides, are reported in four species of Cryptocline Petrak, Comatospora suttonii Pirozynski and Shoemaker, Shanoria bambusarum (Shanor) Subramanian and Ramakrishnan, and Annellolacinia dinemasporioides Sutton. A hitherto inadequately documented pattern of conidium ontogeny is analyzed, and it is suggested to be common among the Coelomycetes.
Extracellular polysaccharide from cell suspension cultures of bush bean (Phaseolus vulgaris cv. Contender)
Authors: Liau Deng-Fong , Boll W. G.
Published: September 2008

High yields of extracellular polysaccharide were obtained from cell suspension cultures of root, hypocotyl, and cotyledon of bush bean. Hydrolysates of the three polysaccharide samples contained the same sugars: galacturonic acid, galactose, glucose, mannose, arabinose, and xylose. The relative amounts of the six sugars were not the same in the hydrolysates from the three sources. The extracellular polysaccharide was produced at all times during the culture cycle. Semilogarithmic plots of increase in cell number, and production of extracellular polysaccharide, indicate that production per cell decreased during the logarithmic phase, and increased at the onset of the stationary phase. Production of extracellular polysaccharide, per culture and per cell, was much higher than that reported for other cell cultures of higher plants.
Foliar nutrition and growth in red pine: distribution of photoassimilated carbon in seedlings during bud expansion
Authors: Rangnekar P. V. , Forward D. F.
Published: September 2008

14CO2 was supplied to shoots of 4-year-old seedlings of red pine, and segments analyzed after 8 h, 3 days, and 7 days. The distribution of 14C after 7 days was similar to that observed earlier in a seedling 6 days after feeding. This pattern of spatial distribution developed within 3 days, after which it was stable.Most of the 14C was found initially in sugars, but redistribution among metabolites continued for 7 days. Transfer to insoluble compounds reached 55–60% in the seedlings, more in the expanding bud and the leaves. Glucose and fructose were initially equally labeled, but the ratio of 14C fructose to 14C glucose increased with time as labeled glucose disappeared more rapidly.Transfer of 14C to quinic and shikimic acids began immediately in the expanding bud and after 3 days these acids contained more of the activity in the bud than sugars. Young leaves also acquired substantial label in quinic and shikimic acids, but the major increase occurred later.
Avenu septentrionalis, and the semispecies concept
Authors: Baum Bernard R.
Published: September 2008

New micromorphological attributes taken from the base of the florets, the lodicules, and epiblasts are shown to be very useful in delimiting the two related taxa A. septentrionalis Malz. and A. fatua. It is pointed out that more research, such as cytogenetics and genetics, is needed to understand better the relationships between these two taxa; this might also be beneficial for breeding oats, especially in view of the fact that no material from this taxon has been used so far.The semispecies concept is here applied and discussed. In this approach the semispecies expresses a state of relationship between two or more closely related species rather than a nomenclaturo-taxonomic category.
The flavonoids of Cladothamnus pyrolaeflorus
Authors: Bohm Bruce A. , Saleh Nabiel A. M.
Published: September 2008

The total flavonoid complement of leaves of Cladothamnus pyrolaeflorus Bong. (Ericaceae) has been determined. Four mono- and two di-glycosides of kaempferol and two mono- and two di-glycosides of quercetin were isolated and identified. The structures agree with compounds reported to occur in the family.
Seasonal ionic fluctuations in a Phragmites communis community
Authors: Bayly Isabel L. , O'Neill Tom A.
Published: September 2008

Calcium, magnesium, potassium, sodium, and phosphorus concentrations were measured in the shoots of a Phragmites communis community and its natural substrates during the growth season of 1969. Shoot length and shoot moisture were determined as indicators of physiological age. In addition, organic decay was followed by determination of the soil organic matter content and cation exchange capacity. Of the ions studied, calcium apparently increased in the shoot tissue, and magnesium, potassium, and phosphorus apparently decreased in the shoot tissue during the course of the growing season. Some speculations regarding the direction of net nutrient on flow in this community are advanced.
Embryological studies on hybridization between Theobroma cacao and Theobroma grandiflora
Authors: Martinson Veronica A.
Published: September 2008

In a comparative study of embryo development in intraspecific (U6 × K5/353) and interspecific (U6 × T33) crosses of Theobroma, the development of the embryo sac as described by previous authors was confirmed. Disintegration of synergids showed that the growth of the pollen through the style was slightly quicker in intraspecific than in interspecific crosses, but the number of embryo sacs which had received male nuclei 3 days after pollination was about the same. Although gametic fusion and endosperm formation in the intraspecific cross was in advance of those in interspecific cross, the major blockage in species hybridization occurred subsequent to fertilization, and in most instances, well after the proembryo stage. Abnormal cell division and cell differentiation were contributory factors to poor seed formation. Possible causes of the abnormality have been discussed.Autonomous enlargement and the binucleate appearance of the egg cells in the unpollinated flower suggested a tendency to parthenogenesis and diploidization of the egg cell, under special conditions. Although a large proportion of the cacao seeds observed in the species crosses are most probably intraspecific seedlings arising from contamination after controlled pollinations, the occurrence of a small number of true maternal seeds cannot be ruled out altogether.
Arceuthobium pusillum: moisture requirements for germination and radicle growth
Authors: Bonga J. M.
Published: September 2008

Seeds of Arceuthobium pusillum were exposed to water, to various relative humidities, and to water followed weekly by various periods of dryness. With water, the seeds germinated more rapidly and produced longer radicles than with water in vapor form at any of the relative humidities used. At relative humidities between 90 and 100%, most of the seeds eventually germinated but the radicles remained short. Below 90% relative humidity, only a few seeds germinated. Some seeds germinated and produced radicles if exposed to weekly dry periods of up to 4 days.It is concluded that the distribution of the parasite is affected directly by water in liquid form, and indirectly by water in vapor form.