bluuebunny/crossref_metadata_2025 huggingface dataset:
DEVELOPMENTAL STUDIES OF ELODEA CANADENSIS MICHX.: I. MORPHOLOGICAL DEVELOPMENT AT THE SHOOT APEX
Authors: Dale Hugh M.
Published: August 2008

The shoot apex consists of a few initial cells at the tip of a thimble devoid of leaf initials for at least 100 μ. Leaf primorida are initiated from the superficial layer of cells, whereas branch buds arising among the; very youngest leaf primordia are produced deeper in the apex. Chinks occur where three or more cell walls come together. The tissue of the stem for the first 200 μ has no internodes. Two squamulae intervaginales lie on the adaxial surface of each leaf with which their development is associated. Internodes are initiated by the longitudinal growth and division of cells from the bottom of the leaf insertion disks. Cells of the young node divide longitudinally to increase the diameter of the nodal disk and to split the intercalary meristem into segments. Internodes are thus initiated with lacunae. Cells destined to become wood vacuolate at the seventh leaf whorl. Scalariform thickenings are produced but quickly disintegrate along with the rest of the xylem cells leaving a lacuna in the center of the stem. The bast surrounding the central xylem differentiates only slightly, beginning at the 20th leaf whorl, whereas the leaf traces and vertical cortical strands are apparent in younger tissue.
ON THE EXTRACTION OF ENZYMES FROM SUCCULENT PLANTS
Authors: Coles C. H. , Waygood E. R.
Published: August 2008

The extraction of enzymes concerned with malic acid metabolism from succulent plants, notably Bryophyllum calycinum, has been made possible by the introduction of a new technique. The high concentration of organic acids in the vacuoles of leaf cells was neutralized in situ by vacuum infiltration with ammonia solution. Thus, during maceration, the enzyme proteins are neither precipitated nor inactivated and conventional methods of enzyme purification may be applied. Further experiments have shown that whereas B. calycinum plants may lose their ability to fix carbon dioxide actively in the dark following exposure to short days ([Formula: see text] hours) the enzymes involved in malic acid metabolism and carbon dioxide fixation in the dark are not necessarily depleted.
SEDIMENTARY CHLOROPHYLL DEGRADATION PRODUCTS IN SURFACE MUDS FROM CONNECTICUT LAKES
Authors: Vallentyne J. R. , Craston Dennis P.
Published: August 2008

Amounts of sedimentary chlorophyll degradation products were determined for surface sediments from nine Connecticut lakes. The relationship between sedimentary chlorophyll degradation products in the ignitable matter of the mud and the hypolimnetic oxygen deficit: was not significant at the 5% level, nor was the relationship between the former and the average summer seston chlorophyll. Shallow water sediments tended to have lesser amounts of sedimentary chlorophyll degradation products than deep water sediments.
DEVELOPMENTAL STUDIES OF ELODEA CANADENSIS MICHX: II. EXPERIMENTAL STUDIES ON MORPHOLOGICAL EFFECTS OF DARKNESS
Authors: Dale Hugh M.
Published: August 2008

A description of the morphological characteristics of sprigs grown in the dark is given. Among the factors that may be responsible for the pattern of growth there is the absence of direct light stimulus, the effect of the sugar solution, the lack of auxins, and the oxygen factor. Experimental evidence suggests that the lack of light per se has little effect upon the form of Elodea. Indole-3-acetic acid in the concentrations used indicate only a stimulation of root production. The effect of the sugar solution appears quite noticeable. Gaseous exchange in cotton-plugged flasks is of significance particularly in dim light. Also, in plants grown with and without added oxygen, in darkness and light, it has been established that the relative amount of oxygen is a major factor influencing not only the size of cells in the leaves and internodes but also the type of air space produced. Finally, changes of gas pressure within the intercellular spaces do enlarge these spaces so that lacunae can be made to occur even in the apical cone.
A COMPARATIVE STUDY OF FUNGITOXICITY AND PHYTOTOXICITY IN AN HOMOLOGOUS SERIES OF N-n-ALKYLETHYLENETHIOUREAS
Authors: Ross R. G. , Ludwig R. A.
Published: August 2008

A comparative study of fungitoxicity and phytotoxicity was made with an homologous series of N-n-alkylethylenethioureas ranging from ethyl to dodecyl. Water solubility decreased and the oil/water partition coefficient increased with increasing length of alkyl side chain. Fungitoxicity increased with increasing chain length up to and including the octyl homologue followed by a sharp decline in the higher members of the series. The more fungitoxic homologues had the same mode of action and the cutoff in toxicity was due to limiting water solubility.The peak of maximum phytotoxicity depended on the availability of the compounds to the plant cells. As the series was ascended the mobility of the homologues in the plant was found to decrease. When the compounds were readily available to plant cells phytotoxicity increased as the series was ascended up to at least the octyl homologue, but when barriers were present, a peak for phytotoxicity was exhibited near the amyl homologue.Studies on the uptake of the compounds from aqueous solutions by potato tissue and Monilinia fructicola spores showed that a distribution equilibrium existed between the tissue or spores and the external solution. With increasing length of side chain the affinity for the biophase increased and hence the differential toxicity could be attributed to the partitioning of the chemical between the two phases.
STUDIES ON LEPTOSPHAERIA AVENARIA f. sp. AVENARIA
Authors: Shaw Dorothy E.
Published: August 2008

Pycnidiospores assignable to Septoria avenae Frank and asci and ascospores assignable to Leptosphaeria avenaria Weber were isolated from cereals and grasses in Canada, but studies herein reported concern only oat-infecting isolates. Macrospores of the oat-infecting organism occurred on green and mature oats during the summer, on oat stubble in the early autumn, and occasionally on old stubble in spring. Microspores were found on mature oats and stubble at the end of August; they occurred abundantly on stubble throughout the winter, and were still present on a few collections in May and June. Immature perithecia were found on stubble in April and perithecia with mature ascospores on June 16, but stubble moistened in the laboratory before that date had discharged mature ascospores.Cultures derived from macro-, micro-, and asco-spores produced macro- and micro-spores in culture; of the 82 cultures derived from single ascospores all except seven formed pycnidia and macrospores, and of the 100 cultures derived from single microspores, all except four formed macrospores. No perithecia were found in culture on various media undar different conditions, or when isolates were paired in various combinations. The macrospores and ascospores have one nucleus per cell, the nuclei of each spore originating from one nucleus. Microspores are uninucleate.Newly discharged ascospores germinated in about 1 hour and macrospores in a few hours in water. Microspores took at least 40 hours to germinate on solid media.In culture, low temperature favored microspore formation and high temperature macrospore formation. Microspores were also found in cultures of Septoria nodorum and S. oudemansii, but not in cultures of L. avenaria f. sp. triticea.The means of overwintering of the organism are discussed; it is considered that, although macro- and micro-spores are available in the spring, ascospores are probably the principal spring inoculum.Oat-infecting isolates did not infect the other cereals or certain grasses, and the oat-infecting isolates were obtained only from oats. The International Rules of Botanical Nomenclature are interpreted to mean that with the erection of the f. sp. triticea, the type automatically becomes L. avenaria f, sp. avenaria (imperfect S. avenae f. sp. avenae).
STUDIES ON LEPTOSPHAERIA AVENARIA f. sp. TRITICEA ON CEREALS AND GRASSES
Authors: Shaw Dorothy E.
Published: August 2008

Cultures were established from pycnidiospores assignable to Septoria avenae Frank collected on wheat, oats, barley, rye, and grasses in Canada. Those cultures that were nonpathogenic on oats produced, in most cases, perithecia and viable ascospores of Leptosphaeria avenaria Weber, as well as the asexual spores. Cultures were also established from asci and ascospores assignable to L. avenaria collected on wheat, oats, barley, rye, and grasses. Those that were nonpathogenic on oats produced, in most cases, pycnidiospores of S. avenae as well as the sexual spores. Many of the isolates produced slight to trace infection on the wheat variety Gaza and trace infection on barley. Oats, rye, and certain grasses were immune. It is considered that the isolates are a plurivorous group slightly pathogenic on wheat and found on the senescent parts of other cereals and grasses, and that they are best assigned to L. avenaria f. sp. triticea. No microspores were found in any of the cultures. Perithecia with viable ascospores formed in 123 cultures out of 164 established from single ascospores, some of the lines being maintained by single ascospore transfer up to five generations. This special form is therefore regarded as homothallic.
STUDIES OF COPROPHILOUS ASCOMYCETES: V. SPHAERONAEMELLA FIMIGOLA
Authors: Cain Roy F. , Weresub Luella K.
Published: August 2008

An emended description of Sphaeronaemella fimicola Marchal refers this species to its proper taxonomic position among the Hypocreaceae, with both perfect and imperfect stages very similar to those of S. helvellae Karsten as described by Seeler. The species, found in nature on dung of various herbivorous animals (rabbit, deer, and cow), is culturable, growing more consistently on V-8 vegetable juice agar than on other media tried, most vigorously in association with other fungi like Aspergillus repens or Microascus sordidus, or with addition of filter-sterilized Czapek's broth in which A. repens had been grown. Fruiting in culture has been erratic; only early transfers from isolations made from field material yielded mature perithecia in pure culture, and then only on V-8 agar; later transfers fruited only in intimate contact with the mycelia of the other two fungi mentioned.
ATKINSON'S SPECIES OF HELMINTHOSPORIUM ON GRASSES FROM ALABAMA
Authors: Shoemaker R. A.
Published: August 2008

Four of Atkinson's Alabama records are confirmed: Helminthosporium ravenelii on Sporobolus poiretii, H. leersii on Leersia virginica, H. flagelloideum on Panicum sp., and H. tuberosum on Secale cereale. H. tuberosum is an earlier synonym for H. secalis, the conidial state of Pyrenophora secalis. The collection of H. inconspicuum on Secale cereale is H tuberosum. The records of H. turcicum on Sorghum halepense, Cinna arundinacea, and Elymus sp. are based respectively on H. sorghicola, H. leersii. and H. sorokinianum, although the last two appeared to be saprophytic.
NOTES ON BOREAL USTILAGINALES, II
Authors: Savile D. B. O.
Published: August 2008

Burrillia acori Dearn. is shown to be on Sparganium; it is apparently not a smut, but fresh material is needed for adequate study. Entyloma circaeae Dearn. is shown to be E. arnicale on Arnica affin. cordifolia. The following range or host extensions are recorded: Cintractia luzulae, Alaska; C. taubertiana, Que., N.B.; Doassansia epilobii, B.C.; D. martianoffiana, B.C.; D. sagittariae, B.C.; Entyloma clintonianum, B.C.; E. compositarum, Labr.; E. winteri on Delphinium brownii, Alta., B.C.; Thecaphora deformans, Alta., Sask.; Thecaphora traillii on Cirsium undulatum, B.C.; Urocystis anemones on Ranunculus cooleyae and R. eschschollzii, B.C.; U. sorosporioides on Aconitum delphinifolium, B.C.; U. heucherae on Saxifraga tolmici, B.C.; Ustilago bullata on Browns ciliatus, Que.; U. tenuispora on Polygonum hydropiperoides, Ont., and P. punctatum, N.Y.; U. violacea vars. on Arenaria lateriflora, B.C. and Ont., on Lychnis triflora, Ellesmere I., on Silene acaulis vars., Spitzbergen, B.C., and Que., on S. douglasii var. villosa, B.C.; Ustilago pinguiculae on Pinguicula villosa, Man., on P. vulgaris, B.C., Alta., and Ont.
STUDIES ON ERGOT INFECTION IN GRAMINEOUS HOSTS
Authors: Campbell W. P.
Published: August 2008

Four hundred and twenty-one isolates of Claviceps purpurea from 38 different host species were cultured on an artificial medium. The conidial cultures were used to inoculate rye, wheat, and barley growing in the greenhouse. All cultures, except one from Glyceria borealis, infected the three host species. Honeydew from rye was used to inoculate 46 gramineous species in the field and in the greenhouse. Every one of these grasses became infected in both locations. It is shown that all indigenous and forage grasses constitute a reservoir of ergot inoculum for rye, wheat, and barley, and that these cereals can be infected provided the environmental conditions are such that inoculum will be disseminated at the time that the cereal crops are in blossom.
THREE CRETACEOUS WOODS FROM THE CANADIAN ARCTIC
Authors: Bannan M. W. , Fry W. L.
Published: August 2008

The structure is described for three new species of coniferous woods from Cretaceous formations in the Canadian Arctic which differ in various features from fossil woods previously recorded. Cedroxylon disjunctum sp. nov. is distinguished by gaps in cell continuity in the marginal rows of the xylem rays, a characteristic not hitherto described for Cedroxylon but found in living conifers such as Abies and Keteleeria. The two Piceoxylon woods possess resin ducts devoid of tylosoids, the ducts in Piceoxylon christopheri sp. nov. having an epithelium which consists entirely of thick-walled, pitted cells, whereas in P. thomsoni sp. nov. the walls of the epithelial cells vary from slightly to moderately thickened.
RESULTS OF INTERFERTILITY TESTS ON SOME SPECIES OF HYMENOMYCETES
Authors: Nobles Mildred K. , Macrae Ruth , Tomlin Barbara P.
Published: August 2008

Tests on 26 heterothallic species of Hymenomycetes have shown that Lenzites abietina (Bull. ex Fr.) Fr., Odontia uda (Fr.) Bres., Peniophora phlebioides Jackson & Dearden, Phlebia merismoides Fr., Polyporus galactinus Berk., P. resinosus Schrad. ex Fr., Poria albipellucida Baxter, P. cinerascens (Bres.) Sacc., P. notata Overh., Radulum casearium (Morgan) Lloyd, Trametes heteromorpha (Fr.) Bres., and T. variiformis Peck have the bipolar type of interfertitity and that Favolus alveolaris (DC. ex Fr.) Quél., Fomes ellisianus And., F. fraxinophilus (Peck) Sacc., Polyporus albellus Peck, P. anceps Peck, P. compactus Overh., P. fumosus Pers. ex Fr., P. hirsutus Wulf. ex Fr. (with possible exceptions), P. pargamenus Fr., P. pubescens Schum. ex Fr., P. supinus Sw. ex Fr., P. volvatus Peck, Poria eupora (Karst.) Cooke, and P. tenuis var. pulchella (Schw.) Lowe have the tetrapolar type of interfertility.
STUDIES ON THE MECHANISM OF DEPOSITION AND EXTENSION OF PRIMARY CELL WALLS
Authors: Setterfield G. , Bayley S. T.
Published: August 2008

Walls of elongating parenchyma and epidermal cells of Avena coleoptiles and onion roots were studied by autoradiography, using C14-labelled sugars, and by electron microscopy of thin transverse sections. The autoradiographs showed that deposition of cellulose takes place over the whole length of the cell, ruling out the possibility of bipolar tip growth. Autoradiographs of cells grown for short times in labelled sugar gave no evidence of localized incorporation of isotope around primary pit-fields, but rather indicated that deposition of microfibrils is finely dispersed over the entire wall surface. The thin sections revealed a marked change in wall structure as elongation proceeds. Walls of young cells contain only transversely oriented microfibrils while older walls include an inner region of predominately transversely oriented microfibrils bounded outside by a region with microfibrils showing an irregular transition to longitudinal orientation. The degree of longitudinal orientation in the outer region increases with cell length. These results for thin walls are consistent with the multi-net model for wall growth deduced by other workers from electron microscope studies on cell fragments. Thin sections have also revealed layering in several types of growing walls which is difficult to interpret on the basis of the multi-net model alone.
THE UTILIZATION OF SINGLE ORGANIC NITROGEN COMPOUNDS BY WHEAT SEEDLINGS AND BY PHYTOPHTHORA PARASITICA
Authors: Newton William
Published: August 2008

The growth of wheat seedlings under aseptic conditions is shown to be well supported by L-alanine, glycine, and urea, but not so well as by nitrate. On the other hand, D-alanine and the optical isomers of leucine exerted toxic effects; seedling growth in these solutions was less than in the cultures receiving no nitrogen, and the presence of nitrate in the nutrients did not reduce their toxic effects. However, the toxic effect of D-alanine was partially offset by L-alanine. A somewhat parallel influence upon the growth of wheat seedlings and P. parasitica was exerted by D- and L-alanine, D- and L-leucine, and glycine, but not by urea. The latter poorly supported the fungus although it helped the growth of wheat. D-leucine is more toxic to P. parasitica than L-leucine, less toxic to wheat seedlings as measured by growth inhibition, but more toxic as measured by chlorotic lesions in the foliage.
THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: IV. THE EFFECT OF MALEIC HYDRAZIDE AND INDOLEACETIC ACID ON THE RUST RESISTANCE OF KHAPLI AND LITTLE CLUB WHEATS
Authors: Samborski D. J. , Shaw Michael
Published: August 2008

Little Club (rust reaction type 4) and Khapli (rust reaction type 1 with race 15B) wheats were grown in sand culture in 1-qt. crocks or 5-in. pots. Daily applications of maleic hydrazide or indoleacetic acid were started 5 days before (10 days after sowing), on the day of, and 5 days after inoculation with stem rust (Race 15B) and were continued for about three weeks. Maleic hydrazide inhibited growth and, at 5 and 10 mg. per pot, flowering. Type 4 pustules developed on Khapli plants treated with 5 and 10 mg. of maleic hydrazide daily from the 5th day before and from the day of inoculation. Indoleacetic acid (0.5 mg. per pot from the 10th day after sowing) stimulated growth and flowering and slightly increased the resistance of Khapli. Treatments started 5 days after inoculation had no effect on rust development on Khapli, and none of the treatments altered the rust reaction of Little Club. Spores produced on plants treated with maleic hydrazide gave normal rust reactions on untreated plants.The effect of maleic hydrazide on the plants and on rust development was not altered by the simultaneous application of uracil, which reversed the growth inhibition caused by thiouracil. Thiouracil inhibited rust development in the presence of maleic hydrazide.
THE ONTOGENY OF ADVENTITIOUS STEMS ON ROOTS OF CREEPING-ROOTED ALFALFA
Authors: Murray Beatrice E.
Published: August 2008

An ontogenetic study of adventitious stem formation on root segments of creeping-rooted alfalfa clones is presented. Unusual meristematic activity is evident first in the phellogen near a lateral rootlet. Continued activity in that region gives rise to a primordial dome from which adventitious stems eventually emerge. Concomitantly, in the subjacent phloem parenchyma cells dedifferentiation and subsequent redifferentiation into vascular tissues occurs. Thus a vascular system is formed which extends from the adventitious stems to the cambium region of the root and, in some instances, to the cambium of the lateral rootlet. Adventitious stems are initiated in secondary tissues of the root. Factors such as age of root, culture treatment, and inherent differences have an influence on adventitious stem initiation.
FACTORS AFFECTING OXIDATION AND PHOSPHORYLATION BY SOYBEAN MITOCHONDRIA
Authors: Switzer Clayton M. , Smith Frederick G.
Published: August 2008

Active particles, presumed to be mitochondria, have been isolated by differential centrifugation from the hypocotyls of etiolated soybean seedlings. These particles were capable of oxidizing all Krebs cycle intermediates tested, although fumarate and oxaloacetate were oxidized relatively slowly. Oxygen uptake in the presence of succinate, pyruvate, or ketoglutarate was increased two to four times by the addition of ATP, MgSO4, and cytochrome c. Maximum activity was obtained when both sucrose and phosphate were added to the grinding and suspending media, and when the reaction mixture was buffered near pH 7.0. Endogenous oxidation was reduced 50% by one washing and at the same time the oxidation of exogenous substrate was increased two to three times. Average P:O ratios of 0.4, 0.8, and 0.9 were obtained without added hexokinase or fluoride for succinate, pyruvate, and ketoglutarate, respectively. These ratios were increased to 0.8, 1.2, and 1.5 by the addition of hexokinase. In all cases, 10−2 M NaF decreased oxygen uptake 30 to 40% without affecting P: O ratios. Isolated soybean particles appear to be similar in most respects to particles from other plants. Certain differences were found and are discussed.
STUDIES OF TILLETIA CONTRAVERSA, THE CAUSE OF DWARF BUNT OF WINTER WHEAT
Authors: Baylis R. J.
Published: August 2008

The occurrence and distribution of dwarf bunt of winter wheat in Ontario since 1952 is noted. While the severity of the disease has not been great, indications are that it is present in most areas of the province where winter wheat is produced in quantity and thus is of concern particularly to growers of seed wheat.The germination of T. contraversa was studied with a view to determining the prerequisites for infection, and the development of dwarf bunt. Chlamydospores incubated on water agar and on ordinary soil at controlled temperatures between 0° and 15 °C. germinated only after incubation for 3 to 4 weeks at relatively low temperature, and required almost 8 weeks to reach a maximum of over 50% of the spores germinated.The germination process to the end point of sporidium development was dependent on light and a temperature about 5 °C. for maximum development. A slightly acid soil reaction favored spore germination, but soil moisture was a more critical factor.In field tests, a correlation was also shown to exist between temperature, light, and soil moisture, and the severity of dwarf bunt infection resulting in winter wheat seeded on infested soil. In continuing tests, chlamydospores have survived 3 years on the surface of soil with very little loss of viability.
THE GENETICS OF SELF-INCOMPATIBILITY IN LESQUERELLA DENSIPILA AND IN THE F1HYBRID L. DENSIPILA × L. LESCURII
Authors: Sampson D. R.
Published: August 2008

The genetics of self- and cross-incompatibility was studied in 12 related families of Lesquerella densipila and in three families of the F1hybrid L. densipila × L. lescurii. Silique swelling was used as the criterion for compatibility. Incompatibility results from the failure of pollen tubes to penetrate the stigmatic surface. Incompatibility in Lesquerella is controlled by a series of multiple S-alleles at one locus. The pollen phenotype is determined sporophytically. A minimum of eight S-alleles was obtained from L. densipila, and two from L. lescurii. Two sorts of gene interaction, independence and dominance, were found among the fully analyzed heterozygotes. Dominance was restricted to the pollen controlling part of the alleles and two levels of potency were established.
SOME EFFECTS OF INCREASING SOIL SALINITY ON PLANT COMMUNITIES
Authors: Keith Lloyd B.
Published: August 2008

Analyses of halophytic vegetation and saline soils adjacent to three different-aged impoundments were conducted on a study area in southeastern Alberta. Two impoundments had been constructed by Ducks Unlimited (Canada), and were 4 and 8 years old. The third was a small natural lake. Mesic prairie vegetation and soils were also sampled to secure comparative data. The establishment of artificial impoundments has raised the water table, permitting a rapid upward movement of soluble salts into the surface soils from lower levels in the glacial drift. Four distinct halophytic communities were recognized: a Hordeum community around all three impoundments, a Distichlis community around the older two, and Suaeda–Chenopodium and Salicornia communities around the oldest (the natural lake). It is believed that as salt concentrations increase the mesic prairie community is replaced by a Hordeum community which in turn is replaced by a Distichlis community. Evidence of Suaeda–Chenopodium and Salicornia communities supplanting the Distichlis community is not clear cut and edaphic factors other than salinity per se are involved.
NATURAL AND ARTIFICIAL × ELYMORDEUM HYBRIDS
Authors: Bowden Wray M.
Published: August 2008

× Elymordeum Lepage is a validly published name for hybrids of Elymus L. × Hordeum L.; × Hordelymus should not be used as a name for these hybrids. Eight × Elymordeum hybrids are listed in this paper: × Elymordeum dutillyanum Lepage (Elymus mollis subsp. mollis × Hordeum jubatum); × Elymordeumschaackianum hybr. nov. (Elymus hirsutus × Hordeum brachyantherum); × Elymordeumpiperi hybr. nov. (Hordeum jubatum × Elymus triticoides); × Elymordeumdakotense hybr. nov. (Hordeum jubatum × Elymus canadensis); !× Elymordeumtriploideum hybr. nov. (2n = 21) (Hordeum distichon × Elymus racemosus var. racemosus); !× Elymordeumstebbinsianum hybr. nov. (Hordeum brachyantherum × Elymus glaucus); !× Elymordeumberkeleyanum hybr. nov. (Hordeum brachyantherum × Elymus condensatus); and !× Elymordeummontanense (Scribn. in Beal) comb. nov. (Elymus virginicus × Hordeum jubatum). Most specimens of !× Elymordeum montanense are nm. montanense; two specimens with pubescent lemma backs are nm. pubescens nm. nov. The parentages of the four hybrids designated by !× have been experimentally confirmed.Most of the parental species of Elymus and Hordeum were tetraploid (2n = 28); the exception was the diploid, (2n = 14), Hordeum distichon. One artificial hybrid, !× E. triploideum, was from Russia; the other hybrids were natural or artificial hybrids from North America. Seven of the parental species of Elymus and Hordeum are native in North America; two occur in Northeastern Asia and North America, one is native in Central Asia and one parent is a cultivated barley. In natural and artificial F1× Elymordeum hybrids, the anthers did not dehisce, the pollen was completely bad, and the spikes never set seed.The natural hybrids of !× Elymordeum montanense occur rarely and sporadically from Montana to Nova Scotia. An artificial F1hybrid was produced in 1954–55 from the cross, Elymus virginicus L. f. virginicus × Hordeum jubatum L. var. jubatum. The artificial hybrid was identical with the natural hybrid from Lower Onslow, Nova Scotia. The hybrids and parental plants were tetraploid, 2n = 28, and there were many meiotic irregularities in the pollen mother cells.
THE PEACH REPLANT PROBLEM IN ONTARIO: V. THE RELATION OF PARASITIC NEMATODES TO REGIONAL DIFFERENCES IN SEVERITY OF PEACH REPLANT FAILURE
Authors: Mountain W. B. , Boyce H. R.
Published: August 2008

Peach production in Ontario is largely restricted to the Niagara Peninsula and Essex County, areas that are separated by some 200 miles but have a similar climate. The peach replant problem has been much more serious in Essex County than in the Niagara Peninsula. A survey of mature peach orchards showed that Pratylenchus penetrans (Cobb, 1917) Sher & Allen, 1953, is considerably more prevalent in peach soils in Essex County than in the Niagara Peninsula. In both areas, orchards that had a previous history of the replant problem had three to four times greater soil population of P. penetrans than those with no such history. Soils of finer texture were shown to limit the populations of P. penetrans, and the relatively low numbers of this nematode in the Niagara Peninsula appear to result from the influence of the finer soils prevailing in that region. The effect of different soil-particle sizes on the build-up of P. penetrans may explain the distribution of the peach replant problem in Ontario.
THE PEACH REPLANT PROBLEM IN ONTARIO: VI. THE RELATION OF PRATYLENCHUS PENETRANS TO THE GROWTH OF YOUNG PEACH TREES
Authors: Mountain W. B. , Boyce H. R.
Published: August 2008

Further evidence was accumulated indicating that the peach replant disease decreases in severity as the interval increases in time between removal of the old orchard and the planting of new trees. The ameliorating effect of the interval may be related to the decline of Pratylenchus penetrans (Cobb, 1917) Sher & Allen, 1953. In experiments, increased growth of peach was associated with the control of P. penetrans by nematocides and P. penelrans was found to be the first nematode to attack newly developing peach roots. The populations of P. penetrans within such roots increased rapidly, then gradually declined. Generally, ectoparasites appeared later, increased relatively slowly, and occurred infrequently until late in the second growing season. The soils of all commercial peach nurseries in Ontario contain P. penetrans and the nematode may be transported in the roots of nursery stock.
BOTANICAL DERIVATIVES CONTRIBUTING TO THE STRUCTURE OF MAJOR PEAT TYPES
Authors: Radforth N W , Eydy H R
Published: August 2008

Samples of peat from the Fort Churchill area in Manitoba have been investigatedin the hope that a quantitative system would be found to explain peatstructure. 'This entailed the developnlent of a method which would allow detailedstudy of the peat with the organic elements in their in situ position. Thequantitative results, categorized according to botanical relationships, were usedto indicate the structural differences in the samples studied, and also to elucidatethe vegetational succession of the samples. Relationships between subsurfacedetails and surface vegetation are discussed.
CONTROL OF NUCLEAR PROCESSES BY AUXIN IN AXILLARY BUDS OF TRADESCANTIA PALUDOSA
Authors: Naylor J. M.
Published: August 2008

Regulatory effects of auxin on mitosis and DNA synthesis were studied in lateral bud apices of Tradescnntia paludosa. In axillary buds inhibited by the terminal bud, mitoses were absent in a group of cells constituting the initials of tunica and corpus within the apex. The DNA (Feulgen) content of inter-phasic nuclei in this "zone of inhibition" was uniform and no greater than that characteristic of diploid telophase (2C), despite differences in nuclear volume. In subapical bud tissues, mitoses occurred at a low rate. Upon removal of the vegetative shoot tip, this mitotic rate was increased and the previously inhibited nuclei within the apes underwent DNA doubling to 4C, then entered prophase. These results indicate that the interphase synthesis of at least one chromosomal substance (DNA) is under auxin control. Evidence is presented that mitosis is not directly inhibited by this hormone. Naphthalene acetic acid was found to substitute for natural auxin in the inhibition of DNA synthesis.
SOME EFFECTS OF INDOLEACETIC ACID AND MALEIC HYDRAZIDE ON THE RESPIRATION AND FLOWERING OF WHEAT
Authors: Shaw M. , Oaks A. , Samborski D. J.
Published: August 2008

Wheat seedlings were grown in sand culture in 1 qt. crocks. Maleic hydrazide (10 mg. per crock per day) prevented flowering and increased the oxygen consumption per unit dry weight of the first leaves by 20 to 50%, but did not alter the C6/C1 ratio, which was measured by incubating leaf disks with glucose-6-C14 and glucose-1-C14. Indoleacetic acid (0.5 mg. per crock per day) increased oxygen uptake by only 10 to 15%, but stimulated flowering and apparently lowered the C6/C1 ratio. The C6/C1 ratio of leaf disks was approximately halved by 2 hours pretreatment with 5.0 and 8.3 p.p.m. of indoleacetic acid, mainly because of a decrease in the recovery of C6.The results are discussed briefly in relation to the effect of obligate parasites in increasing the indoleacetic acid content and in lowering the C6/C1 ratio of susceptible cereal leaves.
STUDIES ON THE EPIDEMIOLOGY OF CROWN BUD ROT OF ALFALFA IN SOUTHERN ALBERTA
Authors: Hawn E. J.
Published: August 2008

Crown bud rot is widespread in irrigated alfalfa stands in southern Alberta. Rhizoctonia solani Kühn, Fusarium roseum Link sensu Snyder & Hansen, and Ascochyta imperfecta Peck acting alone or in combination produce brown to black lesions on the crown buds of plants in their second and subsequent years of growth. The host plant is most susceptible to the disease in early spring after winter dormancy. Soil temperatures above 16 °C. appear to reduce disease development. Relative occurrence of species isolated from infected buds indicate a succession of fungi. F. roseum is the predominant isolate until the third year of alfalfa growth when its numbers are approximately equalled by R. solani. The latter then decreases in prevalence possibly because of the antibiotic action of saprophytic species of Trichoderma and Penicillium. F. roseum maintains about the same degree of activity throughout the growing season whereas R. solani generally appears most frequently in summer-sampled alfalfa and A. imperfecta in spring samples.
GENETICS AND PHYSIOLOGY OF THE XANTHOPHYLLOUS MUTANT OF THE TOMATO
Authors: Butler L. , Chang L. O.
Published: August 2008

Xanthophyllous is a dominant yellow-leafed mutant; the genotype Xa Xa is lethal in either the seed or the very early seedling stage, while the genotype Xa xa is viable but reacts differently to light intensity than does the normal xa xa plant. The 1: 2: 1 ratio is never realized because less than half the lethals appear as seedlings. The 2: 1 ratio is affected by germination so that under good conditions for germination a 2: 1 ratio is obtained, but under poor conditions the ratio may approach 1: 1. Maximum likelihood formulae are given for calculating linkage when one gene is a dominant with recessive lethal effects, and it is shown that the simple product moment method gives similar results for these data. Xa is in linkage group VII (chromosome 10), and its lethal effect disturbs the monogenic ratios of all genes in this group. The following crossover values between these genes and Xa are found: H 44.5%, pe 50%, t 35.5%, tv31.7%, and ag 46.5%.Under standard growing conditions the pigment concentrations of xanthophyllous contrasted with green is: chlorophyll, 790 instead of 3240 μg./g.; xanthophyll, 54 instead of 211 μg./g.; and carotene, 60 instead of 130 μg./g. Both green and yellow plants, when grown under various intensities and spectral compositions of light, have different responses. Green plants make only limited response to changes in light intensity, whereas Xa xa plants become green and cannot be distinguished from xa xa plants. From 600 to 8000 ft-c. the Xa xa plants show a linear trend of decreasing pigment (increasing yellowness) with increasing light intensity. The hypothesis is advanced that Xa xa plants make as much pigment as do green ones, but a light-dependent reaction breaks down the pigments faster than they are being formed.
NOTES ON NEARCTIC HEPATICAE: XIII. THE GENUS TRITOMARIA (LOPHOZIACEAE) IN ARCTIC CANADA
Authors: Schuster Rudolf M.
Published: August 2008

Only four species of Tritomaria Schiffn. have been described, all found in cold to boreal regions of the northern hemisphere. Of these, only T. quinquedentata (Huds.) Buch has been known from the arctic portions of eastern Canada. The range of this species in Canada east of the 100 meridian is tabulated, and two varieties, var. turgida (Lindb.) Weim. and var. grandiretis Buch and Arnell, are described from the same area. The latter variant is here first recorded from North America: it is presumably a polyploid, possessing larger cells and more numerous oil-bodies. T. heterophylla Schuster is described from materials from northernmost Ellesmere Island. It is allied to T. scitula, from which it differs in purplish pigmentation, broader than long leaves, and spinose-dentate perichaetial bracts. The last peculiarity serves to differentiate it from all other species of the genus. A key to all of the species and varieties, all known from eastern Canada, is given.
FURTHER EVIDENCE OF RESISTANCE IN BERBERIS VULGARIS TO RACE 15B OF PUCCINIA GRAMINIS f. sp. TRITICI
Authors: Green G. J. , Johnson T.
Published: August 2008

Plants of common barberry (Berberis vulgaris L.) were inoculated to determine their reaction to race 15B of wheat stem rust (Puccinia graminis Pers. f. sp. tritici Erikss. & Henn.). Only resistant-type infections occurred on plants inoculated with two pure cultures of race 15B-4 (Can.). Strong circumstantial evidence for the resistance of common barberry to race 15B was obtained from inoculations with sporidia from teliospores produced in the field. Sporidia from teliospores collected from the emmer wheat variety Vernal, which is selective for race 15B, produced only infections of a resistant type, and those from the common wheat variety Lee, also selective for 15B, caused both resistant and susceptible types of infections. Transfer of aeciospores to wheat from the susceptible type demonstrated that 15B was not present. Sporidia from teliospores on the varieties Reliance and Mentana, which are not selective for this race, caused infections of a susceptible type. Resistant-type and susceptible-type infections appeared when barberry leaves were infected with races 29 and 48A.
A NOTE ON THE RATES OF UPWARD TRAVEL OF MOISTURE IN TREES UNDER DIFFERING EXPERIMENTAL CONDITIONS
Authors: Greenidge K. N. H.
Published: August 2008

Observations bearing on the rates of vertical travel of moisture in normal and treated trees of several species are presented. Differences in the speeds of movement deriving from a specific experimental treatment are analyzed statistically, and brief consideration given to a particular aspect of the mechanism of moisture movement in trees.
OCCURRENCE OF POLYPORUS LEUCOSPONGIA IN INDIA
Authors: Bakshi B. K. , Singh B. , Puri Y. N.
Published: August 2008

Polyporus leucospongia Cooke & Harkness, a wood-rotting fungus heretofore known only from montane and subalpine zones in North America, is reported to occur commonly in India in temperate regions above 6000 ft. in the Western Himalayas, on stumps and logs of Cedrus deodara, Picea morinda, and Abies pindrow. A detailed description is given of the fungus as it occurs in India as well as the culture characteristics displayed in pure culture.
THE BIO-ELECTRIC POTENTIALS OF PLANTS AND THEIR FUNCTIONAL SIGNIFICANCE: II. THE PATTERNS OF BIO-ELECTRIC POTENTIAL AND EXUDATION RATE IN EXCISED SUNFLOWER ROOTS AND STEMS
Authors: Fensom D. S.
Published: August 2008

Measurements of rate of exudation and also of biopotentials have been made with excised corn roots growing in vitro and with excised sunflower root–stem preparations growing in pots. Exudation cycles have been found to be controlled by factors endogenous to the living plant. Biopotential cycles correlated with the exudation cycles with maximum exudation at the time when the exudate electrode was most negative. Freshly excised green sunflower stems showed water absorption concurrently in both ends with the rates of water movement variously influenced by air speed, temperature, and light. Biopotential changes were again closely correlated with changes in water movement. The electrokinetic theory of transport will consistently account for all these observations.
STUDIES ON THE FUSARIA WHICH CAUSE WILT IN MELONS: I. THE OCCURRENCE AND DISTRIBUTION OF RACES OF THE MUSKMELON AND WATERMELON FUSARIA AND A HISTOLOGICAL STUDY OF THE COLONIZATION OF MUSKMELON PLANTS SUSCEPTIBLE OR RESISTANT TO FUSARIUM WILT
Authors: Reid James
Published: August 2008

It has been shown that more than one type of isolate of both the muskmelon Fusarium and the watermelon Fusarium occur naturally in infested soil. The isolates of both organisms could be divided into many cultural races, depending on the number of isolations made. Among these cultural races differences were demonstrated in their ability to establish successful host–parasite relationships with their respective host plants. The field reactions of various host varieties were shown to be a function of the races present in the soil at a given time. Fluctuations in the relative frequency of the races present in a field have been shown to occur, as well as changes in the races present.The muskmelon wilt organism penetrated a susceptible host variety between cells in the region of elongation. The cortex was then colonized intercellularly, later intracellularly. The fungus then penetrated the stele, establishing itself in the vessels. Eventually hyphae were present throughout the vessels and later passed out to infect stelar and cortical tissues at various loci.The fungus also invaded the primary meristem intercellularly, later intracellularly, and established itself in young protoxylem vessels or developing cortical cells. Penetration also occurred through tears in the cortex caused by developing secondary roots.Colonization of a resistant host occurred in the same manner, but there was always less fungus in the resistant host than in the susceptible host after comparable time intervals. This difference could not be correlated with the morphology of the resistant host.The effect of temperature on colonization appeared to be on the aggressiveness of the parasite, rather than on the susceptibility of the host.
THE METABOLISM OF INDOLE BY TOMATO-PLANT TISSUES AND EXTRACTS
Authors: Mudd J. B. , Zalik Saul
Published: August 2008

Tomato-plant tissues and homogenates were found to metabolize indole. Tryptophan and indoleacetic acid were identified as reaction products, and in some instances serine was required for indole metabolism. The pH optimum for the reaction was about 5.0. Preparations from zinc-deficient tomato plants metabolized indole more efficiently than those from normal plants.
THE INTERACTION BETWEEN DISODIUM ETHYLENEBISDITHIOCARBAMATE (NABAM) AND MANGANESE
Authors: Ludwig R. A. , Thorn G. D.
Published: August 2008

The investigations reported in this paper show that trace amounts of manganese catalyze the oxidation of nabam. Conversion to ethylene thiuram monosulphide was found to be pH dependent. The results obtained help to explain the apparently anomalous behavior of nabam in earlier oxidation studies.
CYTOTAXONOMY OF EUPHORBIA ESULA IN CANADA AND ITS HYBRID WITH EUPHORBIA CYPARISSIAS
Authors: Moore R. J.
Published: August 2008

In 14 collections of leafy spurge from Ontario and Saskatchewan the chromosome number is 2n = 60. The problem of the correct botanical name of this plant is reviewed; all the North American collections seen are classed as E. esula L. sensu lato. The morphology and cytology of an artificial hybrid, E. cyparissias × E. esula, is described; its chromosome number is 2n = 50 and meiosis is irregular. The name E. × figertii Dörfler usually applied to this hybrid is rejected in favor of the prior name E. × pseudo-esula Schur.
EFFECTS OF TEMPERATURE TREATMENT AND OF A NATIVE INHIBITOR ON SEED DORMANCY AND OF COTYLEDON REMOVAL ON EPICOTYL GROWTH IN VIBURNUM TRILOBUM MARSH
Authors: Knowles Robert Hugh , Zalik Saul
Published: August 2008

Dormancy was encountered in both seeds and seedlings of Viburnum trilobum Marsh. When seeds were exposed to germinative conditions at 20 °C., dormancy was expressed by slow growth of the radicle and hypocotyl in some seeds, and by lack of germination in others. This type of dormancy was found to be associated with the presence of a water-soluble inhibitor, as well as with a need for an appropriate temperature treatment. Epicotyl dormancy, or failure of shoot growth following seedling emergence, was overcome by removal of the cotyledons.
DISCOVERY OF FOSSIL CERATOPHYLLUM DEMERSUM L. IN NORTHWEST TERRITORIES, CANADA
Authors: Terasmae J. , Craig B. G.
Published: August 2008

Fossil Ceratophyllum demersum L. was discovered on sites east of Great Slave Lake, Northwest Territories, Canada. This distribution is both north and east of its presently known range. The palynological evidence supports the conclusion that the climate was warmer than the present when the silt, in which the fossil plant remains were found, was deposited. A radiocarbon age of 5400 ± 230 years (L-428) has been obtained for the sample.
PHOTOSYNTHESIS AND METABOLISM IN MARINE ALGAE: III. DISTRIBUTION OF PHOTOSYNTHETIC CARBON FROM C14O2 IN FUCUS VESICULOSUS
Authors: Bidwell R. G. S. , Craigie J. S. , Krotkov G.
Published: August 2008

F. vesiculosus plants were permitted to carry on photosynthesis in sea water in the presence of either Na2C14O3 or C14O2, and the radioactive products of photosynthesis were examined by chromatography. The main compound in the ethanol-soluble fraction was mannitol, which contained up to 95% of the soluble activity. Citric acid and glutamine also accumulated considerable activity. Alginic acid was the main insoluble product of photosynthesis and appeared to be an active metabolite. Combined fucose also became radioactive, and was shown to be present in two forms. It was released from one by mild acid hydrolysis, but from the other only after much stronger hydrolysis. Neither the addition of nutrient salts to the sea water, nor increase in the amounts of CO2 or carbonate supplied, caused much variation in the relative distribution of C14 among the photosynthetic products.
METABOLIC CHANGES IN DETACHED WHEAT LEAVES FLOATED ON BENZIMIDAZOLE AND THE EFFECT OF THESE CHANGES ON RUST REACTION
Authors: Samborski D. J. , Forsyth F. R. , Person Clayton
Published: August 2008

Stem-rust-infected leaves of resistant (var. Khapli) and susceptible (var. Little Club) wheats were detached and floated on water and benzimidazole, with and without glucose. Khapli leaves were susceptible on water, resistant on 40 p.p.m. benzimidazole, susceptible on 40 p.p.m. benzimidazole with 1% glucose, and resistant on 60 p.p.m. benzimidazole with 1% glucose. Little Club leaves were susceptible in all treatments. Khapli leaves subjected to treatments that increase the endogenous substrate levels, such as floating on water for 2 to 4 days or spraying with DDT 2 or 3 days before detachment, were susceptible on 40 p.p.m. benzimidazole and resistant or partially resistant at higher concentrations.The progressive decrease in protein of detached leaves on water was interrupted on transfer to benzimidazole, after which some resynthesis of protein took place with a corresponding decrease in the soluble nitrogen fraction. Detached leaves on benzimidazole with 1% glucose had more soluble nitrogen than leaves on benzimidazole alone. There was more alcohol-soluble carbohydrate in leaves floated on water than in leaves on benzimidazole.
INFECTION OF BARLEY BY CLAVICEPS PURPUREA
Authors: Campbell W. P.
Published: August 2008

The development of infection of the ovary of Newal barley (Hordeum vulgare L.) by the ergot fungus, Claviceps purpurea (Fr.) Tul., was traced from the time of inoculation until formation of the sclerotia. Penetration took place within 24 hours near the base of the ovule. Initially, colonization was intercellular and confined to the ovary wall but by the fourth or fifth day the fungus began to move intracellularly, penetrating the ovule and also growing out onto the surface of the ovary to form a hymenium. Spores and honeydew were produced within five days of inoculation. The advancing hyphae were seldom found in stylar or stigmatic tissue and then only after the parasite was well established. Usually these structures are pushed upward to form a cap on the maturing sclerotium.