bluuebunny/crossref_metadata_2025 huggingface dataset:
CHROMOSOMES AND TAXONOMY OF EASTERN NORTH AMERICAN POLYGONUM
Authors: Löve Áskell , Löve Doris
Published: August 2008

It is pointed out that cytological, palynological, and morphological investigations support the division of the collective genus Polygonum into natural units. The 13 sections of the collective genus are grouped into six natural genera, two of which include five and four sections, respectively, while the remaining four genera are monosectional. The present paper is a report on combined cytological and taxonomical studies of the genus Polygonum s.str. in eastern North America, including 25 taxa of the section Polygonum (= Avicularia) and one species of the section Duravia. The basic number of chromosomes of Polygonum s.str. is x = 10; all the chromosomes have an almost median centromere and thus cannot be morphologically distinguished from each other. The chromosome numbers within the group range from the diploid number 2n = 20 to the octoploid number 2n = 80. Nine species (12 taxa) are diploid; seven species (eight taxa) are tetraploid; four species (five taxa) are hexaploid, and one species is octoploid. Hybrids between several of these taxa revealed that while most species with even the same chromosome number are so different cytogenetically that their offspring are almost completely sterile, others show such close relationship that they cannot be regarded as more distinct than are intraspecific races. In spite of the use here of a system very different from those accepted in recent North American manuals, no new names or combinations are needed, since all the taxa here studied have been described in acceptable categories by previous botanists. It has been suggested that the great variability of at least one of the collective species included in recent North American manuals might be due to the occurrence of apomixis. This suggestion could not be verified, although a low degree of facultative apomixis is possible. The variation which occurs in the same locality is shown to be caused mainly by the fact that the false populations are composed of several morphologically and biologically distinct taxa at the species level, and the constancy of intraspecific races, even when they are growing together as a result of the activities of man, seems to be the result of a high degree of autogamy.
METABOLISM OF UNIFORMLY LABELLED MALTOSE-C14 INTRODUCED INTO DETACHED WHEAT AND TOBACCO LEAVES
Authors: Krotkov G. , Rizvi S.
Published: August 2008

Uniformly labelled C14-starch was incubated in the presence of saliva yielding radioactive maltose, which was isolated by paper chromatography. When this maltose was introduced into detached tobacco and wheat leaves, it was found to be respired and transformed into other carbohydrates. There was no evidence to indicate that maltose is either a better starch former than glucose or that it acts as a specific glucose donor to fructose in the synthesis of sucrose. No dilution in the specific activity of maltose was observed even under the conditions of starch hydrolysis. This indicates that hydrolysis of starch in vivo does not result in the addition of maltose to the metabolic pool of cells.
MORPHOLOGICAL AND HISTOLOGICAL MODIFICATIONS OF PINE SEEDLINGS INDUCED BY PETROLEUM NAPHTHA
Authors: LaCroix J. D. , Guard A. T.
Published: August 2008

Pinus caribaea, P. sylvestris, and P. resinosa seedlings at various stages of growth were subjected to pre-emergence and postemergence treatments with Standard Weed Killer, a Stoddard solvent naphtha, at the rate of 50 to 1000 gal. per ac. Structural responses were a darkening and wilting of the cotyledons and hypocotyl in young seedlings and a yellowing and burning of the older foliage. Outstanding histological modifications were plasmolysis and cytolysis of the cortex, pith, and mesophyll and stomatal closure. Anatomical variation in pine seedlings is suggested as an explanation for species and organ differences in response to the petroleum spray. Less mature seedlings were more susceptible to the Stoddard solvent than older seedlings. Penetration, once the initial stages had been passed, was rapid, though limited in mature tissues by the thick-walled endodermis. The oil passed through the stomata and moved into the intercellular spaces. Once in the cell, the oil combined with the cell contents causing plasmolysis followed by cytolysis.
STUDIES OF COPROPHILOUS ASCOMYGETES: III. THE GENUS TRIANGULARIA
Authors: Cain Roy F. , Farrow W. M.
Published: August 2008

Two new species are added to the monotypic genus Triangularia. The first, T. angulospora, was found on dung and soil from the Panama Canai Zone; the second, T. obliqua, was obtained from an African collection of the dung of Liberian antelope. The three species of Triangularia are considered to have evolved from species of Podospora (Sordaria) from which they are distinguished by the character of their ascospores. These are angular, usually inequilateral in shape, with a short, broad, hyaline basal ceil or primary appendage, the secondary gelatinous appendages absent or much reduced.
THE NUTRITION OF PHYTOPHTHORA
Authors: Lopatecki L. E. , Newton William
Published: August 2008

Phytophthora cactorum grew well in ammonium–salt media but not in nitrate. Conversely, P. megasperma grew well in nitrate but not in ammonium–salt media. P–parasitica and P. erythroseptica grew well in both, but better in that containing nitrate. All species grew better in the presence of organic nitrogen. Evidence is presented that iron, zinc, copper, and manganese are essential trace metals and that zinc is required in greater concentrations than iron. The optimum requirement for glucose or sucrose was found to be approximately 4%, and the residual sucrose was converted into reducing sugars by all species except P. cactorum. Approximately 50% of the residual sugar remained unchanged in the cultures of this species. The growth rate and sugar consumption increased as the thiamine level was increased from 0.2 to 0.8 mgm. per liter, but the coefficient of sugar utilization remained constant. On the other hand, the percentage of nitrogen in the mycelium decreased markedly as the thiamine content of the medium was increased. It is concluded that with media containing 1% alanine an accurate bio-assay of thiamine can be made over a concentration range of 0,2 to 0.6 mgm. per liter.
CELL SIZE AND SURVIVAL IN CONIFER CAMBIUM
Authors: Bannan M. W. , Bayly Isabel L.
Published: August 2008

The pseudotransverse divisions of fusiform initials by which the cambium of conifers is accommodated to increasing girth tend to occur at relatively high rates of frequency. The overproduction of new initials is accompanied by extensive cell loss. The continuation or reduction of fusiform initials after origin in anticlinal division is evidently related to cell length and extent of ray contacts. The largest fusiform initials generally survive and repeat the cycle of elongation and multiplication by pseudotransverse division. The cells of intermediate length continue or fail in varying proportions, the rate of failure tending to rise with increasing frequency of anticlinal division. As a rule the initials with the largest area of ray contacts persist and those with sparse ray contacts decline. The shortest fusiform initials are usually lost, passing off into maturation or undergoing further diminution to ray initials. The continued selection of the longest of the newly formed fusiform initials, which is operative at all stages in tree growth, undoubtedly contributes to the maintenance of an efficient cell length in the secondary vascular tissues.
AN EVALUATION OF DIFFERENT IONIZING RADIATIONS FOR POSSIBLE USE IN THE GENETIC TRANSFER OF BUNT RESISTANCE FROM AGROPYRON TO WHEAT
Authors: Larter E. N. , Elliott F. C.
Published: August 2008

Ionizing irradiations were employed with the ultimate objective of transferring genes for bunt resistance (Tilletia spp.) from a 56-chromosome wheat–Agropyron derivative to a hexaploid winter wheat, Triticum compactum var. Elgin (2n = 42). Various sources of irradiation, including X-rays, thermal neutrons, and radioisotopes (P32 and S35) were administered to hybrid seeds. The relative "efficiencies" with which these various sources induced chromosome breakage and subsequent translocation were measured by scoring the frequency of multivalents observed in microsporocytes of treated and control F1 hybrid plants. Increments of X-radiation caused a decrease in survival and fertility, as well as in chromosome interchange frequency. Thermal neutrons, on the other hand, caused correspondingly increased interchange frequency with increased dosage. Percentage survival of neutron-treated plants, however, was equal to that of controls. Although percentage survival of hybrid plants treated with the two radioisotopes was low, cytological analyses of P.M.C.'s of surviving plants indicated that the number of translocations induced by these sources remained equal to that of control material.
A CASE OF SOMATIC REDUCTION IN A PREMEIOTIC CELL IN WHEAT
Authors: Knott D. R.
Published: August 2008

An unusual case of somatic reduction was found at first meiotic metaphase in a single anther of a wheat plant. Of 10 reduced cells, four had 22 chromosomes, five had 20, and one was not clearly countable. Chromosome pairing indicated that the reduction had involved a random segregation of homologues.
BEHAVIOR OF ALBINISM IN BROWN AND GRAY CULTURES OF THIELAVIOPSIS BASICOLA
Authors: Stover R. H.
Published: August 2008

Many single spore gray wild type cultures of Thielaviopsis basicola consistently produce an average of 3.5–4.2 albino sectors after 5–10 days growth at 73° ± 3° F. on potato dextrose agar and other media. Sectoring was greatly reduced at fluctuating room temperatures of 76°–87° F. and on certain media. Mass spore transfers from the albino sectors yield albino colonies with a small pigmented area around the center of transfer. Single spore cultures of the albino sectors inevitably revert to the gray parent. In contrast to the gray, brown type cultures rarely produce albino sectors or patches and these yield pure albino colonies that have remained stable for four years. All albino colonies are identical morphologically to the parents except in loss of pigment and a retarded thickening of the chlamydospore walls.The expression of albinism in gray type cultures cannot be explained on the basis of a simple gene mutation. Also, an explanation based on a variable phenotypic change, originating in the cytoplasmic enzyme system controlling pigmentation and under constant genotypic control, is not entirely adequate. The expression of albinism in brown type cultures has the characteristics of a gene-type mutation.
THE ENZYMICALLY CATALYZED OXIDATION OF INDOLEACETIC ACID
Authors: Waygood E. R. , Oaks Ann , Maclachlan G. A.
Published: August 2008

Dialyzed wheat leaf extracts, catalase, and horse-radish peroxidase catalyze the decarboxylation and oxidation of indoleacetic acid at pH 5.0–6.0 in the presence of critical concentrations of manganese and monohydric phenols or resorcinol. The equivalent of 1 mole of carbon dioxide is liberated and 1 mole of oxygen consumed per mole of substrate. Manganic ions formed by a phenol–peroxidase–peroxide system initiate the decarboxylation and oxidation. A naturally occurring ether soluble factor from wheat leaves, and maleic hydrazide, can substitute for the active phenols. Catechol, hydroquinone, pyrogallol, seopoletin, and riboflavin, etc. competitively inhibit the oxidation. The nature of the active peroxide is discussed and a reaction sequence involving an organic peroxide or radical rather than hydrogen peroxide is submitted as being a possibility.
STUDIES ON FUSARIUM WILT OF BANANAS: I. THE BEHAVIOR OF F. OXYSPORUM f. CUBENSE IN DIFFERENT SOILS
Authors: Stover R. H.
Published: August 2008

The behavior in soil of Fusarium oxysporum f. cubense (E.F.S.) Sny. and Hans., the cause of Fusarium wilt or Panama disease of bananas, was studied, using soil dilution plates, soil plates, and buried slide techniques. Soil dilution plates were useful in detecting gross population changes above 500–1000 spores per gram of soil. After six to eight months, initially large populations of Fusarium in artificially infested soil had fallen to below 500 spores per gram of soil but could be detected after two years in or around infested glass cloth strips buried in banana plantations. Apparent differences between population counts in loam and sandy loam were attributed to some defect of the soil dilution plate technique.The soil plate technique consisted in adding 1 gm. of artificially infested soil to a culture dish, moistening the soil with a suitable nutrient, and observing growth and sporulation microscopically or by estimating colony increases on soil dilution plates. An external source of nutrient was essential for germination and sporulation. Among the nitrogen sources tested, 1% solutions of tryptophane and glutamic acid stimulated the abundant production of spores whereas inorganic sources of nitrogen were ineffective. Sporulation was greater in soils dried before plating than in soils maintained at 15–35% saturation. Sporulation was greater in acid sandy loam than in alkaline loam and was abundant below pH 7.0 in all soils. Sporulation in soil plates was sparse or absent below pH 3.5 in acidified loam or above pH 8.8 in sandy loam. The optimum pH for sporulation in acidified loam was about 5.0 and in sandy loam, from about 5.0–7.0. In general, rate of disease spread in soils when they are first planted was correlated with soil texture, pH, and amount of growth and sporulation on soil plates and buried slides. Thus, the soil, rather than the host, appears to be exerting the primary influence on the fungus.Fusarium grew and sporulated abundantly in decomposing diseased banana pseudostems, on the surface of cut-open rhizomes, and in adhering soil, but did not sporulate freely in sap or in the xylem in vivo. Fresh banana sap stimulated the abundant production of spores in soil plates. Evidence is presented suggesting that F. oxysporum f. cubense also sporulates in nature in saprophytic association with certain soil-plant components.
THE PEACH REPLANT PROBLEM IN ONTARIO: IV. FUNGI ASSOCIATED WITH REPLANT FAILURE AND THEIR IMPORTANCE IN FUMIGATED AND NONFUMIGATED SOILS
Authors: Wensley R. N.
Published: August 2008

Soil fumigation with MC-2 (methyl bromide) inhibited many of the fungi found in the rhizosphere of peach replants. This chemical, as well as DD (a propane–propene mixture), induced greater growth of peach seedlings in most soils than either Dowfume W40 (ethylene dibromide) or CBP HI 806. Methyl bromide fumigation also permitted second year replants to develop free of root rot. On the other hand, the use of Dowfume W40, which was ineffective against the fungus flora, usually resulted in greater growth than that obtained in check soils. The soil fumigants used did not modify the depressing effect of toxins on the growth of replants in tree sites although this effect gradually diminished with the passage of time. Fourteen species of fungi out of several hundred isolated from the rhizosphere and root tissues of peach replants in fumigated and non-fumigated peach orchard soils were found to be facultative parasites on the roots of peach seedlings when grown under greenhouse experimental conditions. Of these, Fusarium equiseti, Fusarium moniliforme, Fusarium oxysporum, Fusarium solani, Alternaria tenuis, Myrothecium verrucariae, and members of Mycelia Sterilia were isolated most frequently while Papularia sphaerosperma, Gliomastix convoluta, and species of Coniothyrium, Curvularia, Humicola, Peyronellaea, and Truncatella appeared in the rhizosphere of certain peach trees and not in that of others. The experimental conditions most favorable to the infection of roots by these fungi proved to be low soil moisture combined with high soil temperature.
SOLUBLE CARBOHYDRATES OF WHEAT STEMS AND LEAVES
Authors: Lopatecki L. E. , Longair E. L. , Farstad C. W.
Published: August 2008

Chromatographic evidence indicated that glucose, fructose, and sucrose were present in wheat stems and leaves at stages of growth from early shot blade to maturity. A number of non-reducing oligosaccharides soluble in 80% ethanol were also present in both leaves and stems during this period. Simultaneously, at least one water-soluble oligosaccharide which is insoluble in 80% ethanol appeared in the stems. All oligosaccharides examined produced only glucose and fructose upon complete hydrolysis with invertase or acid.
A TECHNIQUE FOR THE STERILIZATION AND INOCULATION OF WOOD CUT FROM LIVING TREES
Authors: Basham J. T.
Published: August 2008

A method of obtaining sterilized wood blocks much less drastic than those presently in common use has been developed. The treatment is sufficiently mild that only the most superficial of the living parenchyma cells are killed. Samples of balsam fir wood treated by this technique have been successfully inoculated in specially designed tubes with three fungi that attack recently killed balsam in nature. The technique shows promise of reducing the problem of correlating field and laboratory studies of wood decay by avoiding the marked changes in the wood which result from most sterilization methods.
STUDIES ON RUBUS VIRUS DISEASES IN BRITISH COLUMBIA: IV. TRANSMISSION OF RASPBERRY MOSAIC VIRUSES TO FRAGARIA VESCA L.
Authors: Stace-Smith Richard , Mellor Frances C.
Published: August 2008

By means of the leaf-grafting technique, attempts were made to transmit the two component viruses of raspberry mosaic, rubus yellow-net, and black raspberry necrosis, separately and in combination, to three strains of Fragaria vesca L. Only the rubus yellow-net virus was transmitted to the strawberry and it induced severe symptoms. Neither the raspberry aphid, Amphorophora rubi Kalt., nor the strawberry aphid, Pentatrichopus fragaefolii (Ckll.), transmitted the yellow-net virus from raspberry to strawberry, although A. rubi was able to transmit the virus from strawberry back to raspberry.
TOXIN PRODUCTION BY HELMINTHOSPORIUM SATIVUM P.K. & B. AND ITS SIGNIFICANCE IN DISEASE DEVELOPMENT
Authors: Ludwig R. A.
Published: August 2008

The production of toxic substances by Helminthosporium sativum P.K. & B. on a variety of artificial media was evaluated by means of a barley seed germination test. The results suggest that these substances also limit the growth of the organism itself giving a fixed maximum level of toxin production. Destruction of toxin and renewed production continue until some other factor of the medium limits further growth, and culture filtrates then rapidly become inactive. The toxins are relatively nonspecific and appear to affect susceptible hosts by conditioning them to invasion by the organism. A loose correlation was found to exist between toxin production and pathogenicity in a limited number of Helminthosporium strains. Even in the presence of abundant toxin, however, these strains differed in their ability to invade barley seedlings indicating that factors other than toxin production were also involved in pathogenicity.
OBSERVATIONS ON THE ROOT NODULES OF SHEPHERDIA
Authors: Gardner I. C. , Bond G.
Published: August 2008

Nodulated plants of Shepherdia canadensis have been raised in solution culture and shown to be able to grow and increase their nitrogen content in a solution free of combined nitrogen. A fixation of atmospheric nitrogen by the nodules is indicated by the data obtained, and under the prevailing conditions it attained a maximum of about 8 mg. per plant during the first season of growth from seed. The nodule development was secured by the application of an inoculum prepared from nodules of the related genus Hippophaë. Nodulation occurred at pH 6 and 7 but not at pH 5; it was also suppressed by the presence of small amounts of combined nitrogen in the culture solution. The capacity of the nodulated Shepherdia plant to fix nitrogen is probably of ecological importance.
FOUR NEW SPECIES OF CHLAMYDOMONAS
Authors: Lewin Ralph A.
Published: August 2008

Four new species of Chlamydomonas are described. C. euryale was isolated from sea water; C. mexicana, C. philotes, and C. ulvaënsis were isolated from soil. C. mexicana is heterothallic. and C. philotes homothallic.
THE APPLICATION OF A NEW NOMENCLATURAL APPROACH TO UPPER CRETACEOUS PLANT MICROFOSSILS FROM WESTERN CANADA
Authors: Rouse Glenn E.
Published: August 2008

A new system of nomenclature is proposed with the purpose of presenting a scheme which will be applicable to spores, pollens, and other microfossils from all geological ages. A review of previous nomenclatural systems is presented to indicate the historical development of microfossil nomenclature. The applicability of the new system is illustrated by naming 21 new species and four new genera of Upper Cretaceous microfossils from the Comox formation of Vancouver Island and the Oldman formation of southern Alberta. The microfossil conspecti are briefly compared with the assemblage previously reported from the Brazeau formation of western Alberta. Advantages of the new nomenclatural scheme are discussed in the light of future discoveries of plant microfossils, and their application to palaeobotanical and geological problems.
GIRTH INCREASE IN WHITE CEDAR STEMS OF IRREGULAR FORM
Authors: Bannan M. W.
Published: August 2008

In coniferous stems the rate of multiplication of fusiform initials in the vascular cambium by means of pseudotransverse division often fluctuates considerably around the circumference. In fluted stems the frequency of these divisions is appreciably higher and the ratio of survival of the newly formed initials relative to the rate of production lower in the depressions than in the adjoining convex portions of the perimeter. The probability that compression is a factor tending to accelerate the frequency of anticlinal division is indicated by the decided increase in rate in areas of the stem subjected to radial pressure. Higher frequencies of pseudotransverse division are accompanied by reduction in mean cell length of the cambial cells and hence of the derived wood elements.
THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: IVA. THE EFFECT OF MALEIC HYDRAZIDE ON THE CARBOHYDRATE, NITROGEN, AND FREE AMINO ACID CONTENT OF THE FIRST LEAF OF KHAPLI WHEAT
Authors: Samborski D. J. , Shaw Michael
Published: August 2008

Khapli wheat was grown in sand culture in 1-qt. crocks. Daily applications of maleic hydrazide (10 mg. per crock) were started about 10 days after sowing. After 5 to 12 or 15 days of treatment, samples were taken for analysis. Maleic hydrazide inhibited growth and caused increases in the dry weight, total soluble matter, sucrose, and free amino compounds, particularly glutamine and glutamate, in the first leaves. The treated leaves were also rich in starch which does not normally occur in the wheat leaf.
HISTOLOGICAL STUDY OF HOST–PARASITE RELATIONSHIPS BETWEEN SEPTORIA GLYCINES HEMMI AND SOYBEAN LEAVES AND PODS
Authors: MacNeill Blair H. , Zalasky Harry
Published: August 2008

Histological studies of the host–parasite relationships between Septoria glycines Hemmi and soybean have revealed that penetration is stomatal without, the presence of an appressorium. Subsequent spread of the pathogen is intercellular in the mesophyll tissue and in the parenchyma sheath and phloem of the leaf veins. While the fungus does not show marked action in advance and requires to be in intimate contact with vital cells in order to progress through host tissue, its fruiting bodies are matured only in the holonecrotic region of the lesion. The fungus seems incapable of invading the plesionecrotic zone which borders the holonecrotic region; the role of this zone in limiting the pathogen to a discrete spot has been discussed.Colonization of the pericarp and seed is primarily intercellular, although intracellular hyphae may be found in the sclerenchyma of the subhilum region of the seed. Infection of the seed may occur directly at the point of contact of the seed with the wall, or by systemic invasion via the placenta and funiculus. This study establishes conclusively that S. glycines is seed-borne in the soybean.
GROWTH AND MORPHOGENESIS IN THE CANADIAN FOREST SPECIES: II. SPECIFIC INCREMENTS AND THEIR RELATION TO THE QUANTITY AND ACTIVITY OF GROWTH IN PINUS RESINOSA AIT.
Authors: Duff G. H. , Nolan Norah J.
Published: August 2008

Two measures are needed to describe numerically the activity of the internodal cambium in terms of annual increment. These are "specific wood volume increment", a measure of additive growth and "specific increment of cambial area", a measure of multiplicative growth. The mean area of the internodal cambium is the basis of reference for both since it is the measure of that which is active in growth. The former measure of specific growth is numerically equal to ring width and the manner of its factorial control has already been considered. Data for the latter are new.The geometry of the apical meristem and its products is too complex for the ready computation of specific terminal growth, but it can be shown empirically that internode length is a valid measure of apical activity. Analysis of internodal wood volume growth into its three linear components leads to the conclusion that the determinants in control of wood growth act mainly through their effect upon apical activity and upon specific increment of cambial area.
THE BIO-ELECTRIC POTENTIALS OF PLANTS AND THEIR FUNCTIONAL SIGNIFICANCE: I. AN ELECTROKINETIC THEORY OF TRANSPORT
Authors: Fensom D. S.
Published: August 2008

The background of bio-potentials in relation to transport is briefly reviewed and the chief difficulties lying in the way of an electrical theory of transport are pointed out. A re-examination of electro-osmosis and streaming potentials in xylem and phloem vessels suggests that the bio-electrical forces are sufficiently large in magnitude to cause transport and that they certainly operate in a direction to assist it. The productions of the potentials through metabolic activity and membrane diffusion is discussed.
THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: V. A PRELIMINARY EXAMINATION OF THE LEVEL OF FREE ENDOGENOUS INDOLEACETIC ACID IN RUSTED AND MILDEWED CEREAL LEAVES AND THEIR ABILITY TO DECARBOXYLATE EXOGENOUSLY SUPPLIED RADIOACTIVE INDOLEACETIC ACID
Authors: Shaw Michael , Hawkins A. R.
Published: August 2008

The growth substances were extracted with cold alcohol from the first leaves of uninfected, rusted (wheat), and mildewed (barley) cereal seedlings. The acid ether fractions were chromatographed on paper and the chromatograms were cut into sections which were assayed for growth promoting or inhibiting activity in the Avena coleoptile straight growth test. The estimated, free, endogenous indoleacetic acid content of uninfected leaves ranged from 0.5 to 3.2 μg. per kilogram fresh weight. In the early stages of infection this decreased, but increased again to from 5 to about 10 μg. per kilogram fresh weight by the 10th day after the inoculation of susceptible hosts. Indoleacetic acid was not detected in ungerminated uredospores of stem rust (race 15B), but two other growth promoting substances appeared to be present.Leaf disks were incubated with radioactive indoleacetic acid (as —C14OOK) and the radioactivity released as C14O2was measured. The ability of the tissue to decarboxylate the indoleacetate (‘oxidase’ activity) increased sharply, sometimes to as much as 1000%, in the first 3 days after inoculation. With susceptible hosts, this increase was followed by an almost equally sharp decrease to less than 50% of the values for uninfected tissue. With infected, resistant tissue, the secondary decrease in ‘oxidase’ activity was delayed and less pronounced.The results are discussed and a working hypothesis suggested with respect to the relation between susceptibility or resistance and the auxin balance.
REGENERATION IN SPLACHNUM AMPULLACEUM (L.) HEDW.
Authors: von Maltzahn Kraft E. , MacNutt Mary M.
Published: August 2008

Successive leaves isolated from the gametophore exhibit differences in the number of regenerates obtained per organ. Starting from the base, successive leaves show an increasing number of regenerates per leaf. This pattern is similar in leaves isolated from young and older gametophores, although the younger ones show a much greater absolute number of regenerates.No correlation exists between the number of cells per organ and the number of regenerates. Although the size of the wound surface plays an important part in the number of regenerates produced, this factor cannot determine the regenerative pattern between successive leaves.Correlative factors are shown to exist in individual leaves and the distribution of regeneration in the leaf is determined also by these factors.It is concluded that the age of the organ determines the regular pattern of protonematal regeneration of successive organs.
THE pH FACTOR IN THE METABOLISM OF FUSARIUM MONILIFORME SHELDON ON SUCROSE
Authors: Naguib Kaiser
Published: August 2008

A study has been made of the effects of varying the pH value of the culture media on sucrose inversion and absorption, on respiration, and on growth of Fusarium moniliforme Sheldon. The study was carried out on 1-week-old fungal mats that were then subjected to experimentation for 48 hours. Sucrose inversion was almost unaffected by pH values higher than 5.4 but was inhibited at pH 4.0. Sugar uptake was influenced more by lowering than by raising pH beyond 5.4. Carbon dioxide output per unit dry weight of mycelial mat was lowest at the pH optimum for growth, as measured by mat dry weight. At the same optimum pH there was also the highest rate of sucrose inversion and uptake. It seemed, therefore, that the effect of pH on growth was the additive effects on the different enzymatic processes operating in the metabolism of the fungus. It is also suggested that the external pH of the medium might act by the invasion of hydrogen or hydroxyl ions into the mycelial cells, thus changing the internal pH.
AN ASSOCIATION BETWEEN VARIABILITY IN OVULE DEVELOPMENT WITHIN OVARIES AND SELF-INCOMPATIBILITY IN LOTUS (LEGUMINOSAE)
Authors: Bubar J. S.
Published: August 2008

Ovules within each ovary of self-fertile Lotus species develop uniformly while those within each ovary of self-sterile species vary considerably in rate of development. All ovules in self-fertile species may be fertilized while less than one-half of those in self-sterile species are generally fertilized. Time of pollination is determined by the time when the stigmatic membrane ruptures in self-fertile species, by the time of rupturing by pollinating insects in self-sterile species. Higher numbers of ovules per ovary compensate for the proportion not fertilized in self-sterile species. The relationships of self-sterility to self-incompatibility in this genus, the evolution of this mechanism, and evidence that similar mechanisms are found in other legumes are discussed.
STUDIES OF THE KETO ACIDS OF WHEAT: II. GLYOXYLIC ACID AND ITS RELATION TO ALLANTOIN
Authors: Krupka R. M. , Towers G. H. N.
Published: August 2008

In order to determine the metabolic origin of glyoxylate 12 different carbon-14 labelled compounds, including sugars, organic acids, and amino acids, were fed to wheat tissue. With the exception of glycine none gave rise to glyoxylate. The labelling from glycine was slight and could not have accounted for the large amounts of glyoxylate in the tissue. Of a number of inactive compounds fed to degrained seedlings only allantoin induced an increase in the concentration of glyoxylate. A nitrogen atmosphere was found to increase the content of glyoxylate while decreasing that of allantoin. Allantoin-C14 was synthesized much more readily from glycine-C14 than from glyoxylate-C14. When seedlings previously fed glycine-C14 in air were transferred to nitrogen, considerable radioactivity appeared in glyoxylate. These results suggest that glycine is a precursor and glyoxylic acid a hydrolysis product of allantoin.
MINERAL NUTRIENT CONTENT OF SOME FOREST PLANT LEAVES AND OF THE HUMUS LAYER AS RELATED TO SITE QUALITY
Authors: Gagnon D. , Lafond A. , Amiot L. P.
Published: August 2008

The nutrient content of the humus and of some of the plants characteristic of different site classes has been studied. Analyses carried out on fresh healthy leaf material from typical forest plants indicated no differences within a given species that could be related to site quality. Available nutrient content of the A0 horizon collected in the same environment is, however, closely related to the productivity of the sites. It seems, therefore, that the differential accumulation of nutrient elements in the cells of the forest plants studied depends upon the inherent properties of the species rather than on the quantity of available nutrients in the humus on which they grow.
APPLICATION OF A NEW LABORATORY METHOD FOR THE DETERMINATION OF THE SURVIVAL OF HELMINTHOSPORIUM SATIVUM SPORES IN SOIL
Authors: Chinn S. H. F. , Ledingham R. J.
Published: August 2008

A laboratory method is described for determining the survival of Helminthosporium sativum spores in soil. An oil–water emulsion containing the spores is mixed with potato dextrose agar supplemented with molasses; microscope slides are then dipped into the mixture, incubated, and examined for spore germination. Application of the method showed that viability of spores in a dry soil did not decline over a 9-month period whereas survival of spores in saturated soil dropped markedly in the same period. Intermediate moisture levels had intermediate effects on the spores. Studies on spores obtained directly from cultivated fields indicated little mortality from fall to spring. A summerfallow year between two wheat crops resulted in a substantial decline in percentage of viable spores.
RESISTANCE TO VERTICILLIUM WILT IN F1 GENERATIONS OF SELF-FERTILIZED SPECIES OF FRAGARIA
Authors: Newton W. , Adrichem M. C. J. van
Published: August 2008

The F1 generation of selfed plants of Fragaria chiloensis, F. ovalis, and F. yukonensis contained seedlings resistant to the verticillium wilt disease. Selfed F. orientalis plants yielded seedlings that carried considerable tolerance but selfed F. vesca, F. bracteata, and F. virginiana plants yielded neither tolerant nor resistant seedlings. Asexually propagated plants of the seven species were all susceptible to the disease.
THE OCCURRENCE OF INORGANIC ELEMENTS IN MARINE ALGAE OF THE ATLANTIC PROVINCES OF CANADA
Authors: Young E. Gordon , Langille W. M.
Published: August 2008

Specimens of numerous marine species of the green, red, and brown algae from the Atlantic coast of Canada have been analyzed for total ash, Na, K, Ca, and Si, and the trace elements, As, Co, Cu, F, I, Mn, Mo, Ni, Pb, and Zn. Figures for fluorine in seaweeds are recorded for the first time. Thorough washing with tap water lowered the content of the ash, Na, K, and Si, but did not affect appreciably the concentrations of other elements.Accumulation from the sea water was apparent in greatly varying degrees in the following ascending order: F, Mo, Co, Cu, As, Ni, Mn, Zn, I. The ranges in concentration observed were Na 1.6–4.7, K 2.3–7.1, Ca 0.9–2.3, Si 0.5–2.0, as percentage of dry matter; I 20–2490, Zn 35–97, Mn 20–50, Cu 6–62, As 2–75, F 2–22, Pb 0.8, Ni 0.3–2, Co 0.1–0.7, Mo 0.2–1.4 as p.p.m.No seasonal variation was detectable in the concentration of trace elements in Chondrus crispus. Differences in concentration were observed between frond and stipe in two species of Laminaria.
STUDIES ON FUSARIUM WILT OF BANANAS: II. SOME FACTORS INFLUENCING SURVIVAL AND SAPROPHYTIC MULTIPLICATION OF F. OXYSPORUM f. CUBENSE IN SOIL
Authors: Stover R. H.
Published: August 2008

The effect of 1% glutamic acid, banana sap, water, and carbon dioxide on multiplication (sporulation) of Fusarium oxysporum f. cubense (E.F.S.) Sny. and Hans. in infested soil was studied under laboratory conditions. Increases in population were determined by microscopic examination and dilution plating on peptone dextrose agar containing rose bengal and streptomycin. Amount of fungus multiplication varied among different soils, samples from the same soil, and different experiments. This is attributed to unknown variables influencing multiplication and survival in soil microhabitats.Carbon dioxide stimulated multiplication of the fungus in aqueous soil extracts and in soil amended with 1% glutamic acid or banana sap, and sometimes in soils moistened with water. Initially low and high population increases in control soil in air required 42 hours' exposure in an atmosphere containing 4 to 25% and 8 to 25% carbon dioxide, respectively, for optimum multiplication. In some instances, multiplication was stimulated as a result of 8 hours' exposure to 4% carbon dioxide in air, and amount of stimulation increased with longer exposures up to 24 or 42 hours. Oxygen did not consistently limit multiplication in soil plates at a concentration of about 4% in nitrogen containing 4% carbon dioxide. Differences in amount of multiplication between a series of acid loams or sandy loams and alkaline clay loams were, in general, more consistent in air enriched with carbon dioxide than in air. Multiplication was greater in soil previously flood fallowed and in soil subjected to anaerobiosis than in non-flood fallowed soil.The above evidence supports the thesis that F. oxysporum f. cubense can multiply saprophytically in soil.
FACTORS AFFECTING ION RETENTION AND VARIATION OF OSMOTIC PRESSURE IN WATER HYACINTH ROOTS
Authors: Minshall Wm. Harold
Published: August 2008

The osmotic pressure of the root cells of water hyacinth [Eichhornia crassipes (Mart.) Solms.] decreased approximately one-half an atmosphere from its normal value of 5.0 to 5.6 atmospheres (a) in roots severed from the plant, (b) in roots of plants that were darkened for 24 hours or more, and (c) in roots of plants growing in a nutrient solution without renewal for a week or more. This decrease in osmotic pressure was associated with a decrease in the internal concentration of inorganic ions. In excised roots an exosmosis of nitrate and potassium was demonstrated. This exosmosis did not appear to be connected with the passive leakage of diffusion processes. A deficiency of oxygen in the internal aeration system of the plant appeared to be the most likely cause of the exosmosis of ions from severed roots and from roots of plants held in the dark. Root cells of water hyacinth accumulated the vital stain neutral red but were not able to retain this stain when transferred to tap water or to a hypotonic sugar solution.
PHOTOSYNTHESIS AND METABOLISM OF MARINE ALGAE: II. A SURVEY OF RATES AND PRODUCTS OF PHOTOSYNTHESIS IN C14O2
Authors: Bidwell R. G. S.
Published: August 2008

The rates and products of photosynthesis of 14 species of brown, red, and green marine algae have been determined. C14O2was supplied in a special apparatus which gave a continuous record of uptake. This apparatus is described in detail. The products of photosynthesis were extracted, separated by paper chromatography, and their radioactivity was determined. The main product was invariably mannitol in the brown algae, floridoside or a glycerol-mannoside in the reds, and sucrose in the greens. Hydrolysis of the insoluble residues released radioactive amino acids, glucose, galactose, and other carbohydrates. Although the soluble products were characteristic of each group, the insoluble products were much the same in all three groups. The rates of CO2assimilation ranged from [Formula: see text] to 4 mg. of CO2per hour per gram of fresh plant. No correlation of the rate of CO2uptake was observed with either the morphology or the taxonomy of the algae.
STUDIES ON RUBUS VIRUS DISEASES IN BRITISH COLUMBIA: V. THIMBLEBERRY RING SPOT
Authors: Stace-Smith Richard
Published: August 2008

A ring spot mottling that occurs on the wild thimbleberry (Rubus parviflorus Nutt.) in British Columbia was proved to be caused by a virus. The virus was transmitted to thimbleberry, black raspberry (R. occidentalis L.), red raspberry (R. strigosus Michx.), and R. henryi Hemsl. & Kuntse. Three species of aphids belonging to the genus Amphorophora transmitted the virus, but the large raspberry aphid (A. rubi Kalt.) was not a vector. The name "thimbleberry ring spot" is proposed for the virus and the disease.
S-ALKYL-2,5-DIMERCAPTO-1,3,4-THIADIAZOLES
Authors: Thorn G. D. , Ludwig R. A.
Published: August 2008

The synthesis and some fungitoxicity and phytotoxicity data are given for 2,5-dimercapto-1,3,4-thiadiazole and a series of its n-alkyl thioethers. These compounds exhibit a good measure of fungicidal activity, but would appear to be too toxic to the plants to be practical field fungicides.
INHIBITION SÉLECTIVE DE LA PHOTOSYNTHÈSE PAR LE MÉTHANOL CHEZ SCENEDESMUS
Authors: Lefrançois Marcel , Ouellet Cyrias
Published: August 2008

In the presence of methanol at concentrations up to 12% by volume, photosynthetic fixation of C14O2 into glycolic acid, glycine, alanine, serine, and an unknown compound proceeds at nearly normal rates over periods of 1 to 8 minutes. However, fixation into other compounds, such as phosphoglyceric, phosphopyruvic, and aspartic acids and the lipids, is suppressed over induction periods of several minutes. The results indicate that methanol inhibits the photosynthetic cycle, thus unmasking an alternative path of fixation into the simple acids. It is suggested that the initial step is the carboxylation of phosphoenolpyruvic acid.
DECAY OF TREMBLING ASPEN
Authors: Basham J. T.
Published: August 2008

A total of 1754 aspen trees were examined on 47 sample plots located in even-aged stands considered representative of the study area. Decay was found in the merchantable portions of the trunks of 1212 or 69% of these trees. Three types of heart rot were encountered, viz., a white spongy trunk or butt rot and a yellow stringy trunk rot associated respectively with Fomes igniarius var. populinus (Neu.) Campb., and Radulum casearium (Morgan) Lloyd; and stringy butt rots from which several fungi, notably Pholiota spectabilis Fr. and Armillaria mellea (Vahl ex Fr.) Quél., were isolated. Two heartwood stains, one brown and the other mottled red, were present in many of the aspen trees examined. Corticium polygonium Pers. and two members of the Fungi Imperfecti, Libertella sp. and Phialophora alba van Beyma, were consistently isolated from these stains and from incipient decays. Fructifications of F. igniarius were the most reliable external indication of heart rot in this species. A pronounced relationship existed between age and decay. Older stands as a rule contained higher proportions of decayed heartwood than young stands. A less pronounced relationship was found to exist between soil conditions and decay; trees occurring on drier sites were somewhat more decadent than those growing on moist sites. The possible reasons why the decay process in the heartwood of living aspen is one in which certain fungi, mainly Fungi Imperfecti, colonize and stain the wood prior to its invasion and destruction by the Basidiomycetes associated with advanced decay are discussed.
STUDIES ON THE FUSARIA WHICH CAUSE WILT IN MELONS: II. THE EFFECT OF LIGHT, NUTRITION, AND VARIOUS CHEMICALS ON THE SPORULATION OF CERTAIN FUSARIAL ISOLATES, AND PRELIMINARY INVESTIGATIONS ON THE ETIOLOGY OF WILTING OF THE MUSKMELON FUSARIUM
Authors: Reid James
Published: August 2008

Light was shown to affect the amount of macrospore production in a number of Fusarium species. Macrospore production and the ratio of macrospores to microspores increased with increasing light intensity and vice versa. Only colony areas exposed to light during active growth produced macrospores on potato dextrose or Czapek's agars. Light also greatly stimulated macrospore production on V-8 vegetable juice agar. Both carbon and nitrogen sources were also important in determining the kind and amount of sporulation in the species tested. Colony growth was appressed in light, and pigmentation of the mycelium often was produced in response to light.Various chemicals, known to be enzyme inhibitors, induced different effects on growth and sporulation, depending on the substrate used as the carbon source. For example, sodium fluoride inhibited growth and sporulation when glucose was the substrate, but was without effect when sodium acetate, which supports equally vigorous growth, was the substrate.Studies on the etiology of wilting indicated that the muskmelon Fusarium produces at least three chemical fractions which may contribute to wilting. One was thermostable, non-dialyzable, apparently a protein, and possibly an enzyme. The second was thermostable and was probably a low molecular weight carbohydrate. These two induced wilting in plant cuttings rather than in intact plants, whereas the third fraction induced wilting in plants with undamaged root systems, and was thermostable, partially dialyzable, and stable through a wide pH range. Appropriate tests, however, indicated also that translocation through the vessels was significantly interfered with in plants showing incipient or more advanced wilting symptoms.
CYTOTAXONOMIC STUDIES ON EREMOPYRUM
Authors: Sarkar Priyabrata
Published: August 2008

Five species are included in the genus Eremopyrum, namely, E. triticeum, E. hirsutum, E. buonapartis, E. orientale, and E. distans. Of these, the first two are diploids with 2n = 14, while the rest are tetraploids with 2n = 28. The karyotypes of the two diploid species are different from those of any other member, of the Triticineae in that they have chromosomes with extremely subterminal centromeres. The karyotype of each of the three tetraploid species shows a mixture of two types of chromosomes: seven pairs with extreme subterminal centromeres and the other seven pairs with median or submedian centromeres. This indicates that these are amphidiploids between triticeum–hirsutum-like taxa and perhaps some diploid species of crested Agropyron. In view of the karyotypic peculiarity, annual habit, and reported sterility barrier, the decision to give Eremopyrum generic status is supported.
CYTOLOGICAL STUDIES OF VENTURIA INAEQUALIS
Authors: Julien J. B.
Published: August 2008

A cytological study of Venturia inaequalis has revealed that only one meiosis occurs in the ascus, and that the haploid number of chromosomes is seven. Most asci originate through typical hooks, but in a number of perithecia these croziers are absent, and large budding cells give rise to small ascus-shaped structures. Variations in nuclear stainability were observed among perithecia at the same stage of maturity. Attempts were made to characterize the seven chromosomes.