bluuebunny/crossref_metadata_2025 huggingface dataset:
NOTES ON SOME INTERESTING NORTH AMERICAN FUNGI
Authors: Reid James , Pirozynski K. A.
Published: August 2008

Described as new are Ceratophacidium J. Reid & Pirozynski gen. nov., type species Ceratophacidium aristosporum (Bonar) J. Reid & Pirozynski, comb. nov. (=Pezizella aristospora Bonar); Dermea grovesii J. Reid & Pirozynski, sp. nov.; Hemimyriangium J. Reid & Pirozynski, gen. nov., type species Hemimyriangium betulae J. Reid & Pirozynski, sp. nov. The taxonomy of these organisms is briefly discussed.
STUDIES ON THE RELATIONSHIP BETWEEN WATER MOVEMENT AND WATER CHEMISTRY IN MIRES
Authors: Sparling J. H.
Published: August 2008

Fifty-four sites were selected in a number of mires in Ontario, and rates of water movement were measured on a number of occasions. The rates of water movement ranged from less than 0.1 cm sec−1 to over 8 cm sec−1. The oxygen concentration of the mire waters increased with increasing flow rate, approaching saturation at rates over 1 cm sec−1. From a model it was shown that at a flow rate of less than 0.3–0.4 cm sec−1 the diffusion of oxygen into the water would be similar to simple diffusion into a stationary water surface, and because of the respiration of roots and microorganisms in the peat, the oxygen would tend to be depleted. Above flow rates of 0.4 cm sec−1 the water is agitated, and is continually replenished with oxygen from the atmosphere. Reduced states of iron and manganese were shown to be in solution at concentrations greater than 0.1 mg/1 only at low rates of water flow. The pH was also shown to increase with faster rates of water movement, the increase depending on the base status of the mire. Aluminium is in solution only in situations of low water movement where more acidic conditions are prevalent.
DNA SYNTHESIS IN PRIMARY ROOT OF GLYCINE MAX DURING GERMINATION
Authors: Miksche Jerome P.
Published: August 2008

The percentage number of cells in S (cells which are undergoing DNA synthesis at time of treatment) in 4-mm root tips during early stages of germination was determined by tritiated thymidine and liquid emulsion autoradiography. Labeled nuclei were observed within all anatomical regions of the primary root 24 hours after seeds were sown and the observed labeling did not follow the known pattern of mitotic reactivation. This would indicate that DNA synthesis was not closely-related to the onset of mitosis during germination. The percentage of cells labeled was 10% at 24 hours, approximately 3% at 32 through 48 hours, and 10% at 60 through 96 hours after seeds were sown. The 3% labeled cells at 32–48 hours after planting may indicate a large population of G2 cells but this was not in accordance with a previous study on Glycine max, in which DNA per cell was determined. A greatly reduced labeling over the stelar and common initial regions indicates the existence of a quiescent zone in the embryonic root.
FROST RING FORMATION IN THE STEMS OF SOME CONIFEROUS SPECIES
Authors: Glerum C. , Farrar J. L.
Published: August 2008

Seedlings of several conifer species were artificially subjected to freezing temperatures. Microscopic examination of sections, taken at intervals after the frost, revealed the way in which frost rings developed. Differentiating tracheids and xylem mother cells were killed by the frost, leaving a permanent band of underlignified and crumpled tracheids inside a band of dead cell tissue. Most of the cambial initials remained alive but developed abnormally into short irregular tracheids. Parenchyma cells proliferated mainly from the xylem ray cells. With subsequent growth, the growing stresses, which had become subnormal because of the collapse of killed cells, were restored. This was accompanied by the reestablishment of the cambium to its normal form.
CYTOTAXONOMIC STUDIES ON NEW WORLD SPECIES OF ANEMONE (SECTION ERIOCEPHALUS) WITH TUBEROUS ROOTSTOCKS
Authors: Joseph Cecily , Heimburger Margaret
Published: August 2008

The American species of Anemone L. (section Eriocephalus Hook. f. & Thoms.) with tuberous rootstocks were studied by biosystematic methods. Anemone caroliniana Walt., A. heterophylla Nutt. ex Torr. & Gray, A. tuberosa Rydb., and A. edwardsiana Tharp (tentatively) are recognized from North America and A. decapetala Ard., A. triternata Vahl, and A. cicutifolia Johnst. from South America. Karyotypes of the diploid species (2n = 16), A. heterophylla, A. tuberosa, A. decapetala, and A. triternata are described. They resemble the karyotype of A. caroliniana published earlier. Anemone edwardsiana and A. cicutifolia are also presumed diploid from stomatal and pollen grain studies. A new taxon (2n = 32), of undecided status, was obtained from Chile. North American plants included by authors in A. decapetala are here referred to A. heterophylla. The North and South American species appear to form two separate groups, the species of each continent being more closely related among themselves than to those of the other continent. Fewer stomata, larger chromosome size, and higher DNA content are characteristic of the North American species. Additional support for the separation of the two groups derives from limited meiotic studies which indicate a larger number of inversion differences in inter- than in intra-continental hybrids.
CHROMOSOME MORPHOLOGY OF THE NORTH AMERICAN SPECIES OF ACTAEA (RANUNCULACEAE). I
Authors: Kawano Shoichi , Kane James M. , Iltis Hugh H.
Published: August 2008

Karyotypes of three eastern North American taxa of Actaea were investigated. Their karyotypes are as follows:[Formula: see text][Formula: see text][Formula: see text]Actaea rubra and its albino f. neglecta have identical karyotypes. The karyotypes of A. rubra f. rubra and A. pachypoda, two very distinct species, though similar, are clearly differentiated by the presence of a secondary constriction at the distal end of the long arm in the shorter of the two pairs of J-shaped chromosomes of A. pachypoda. The karyology of the three North American taxa is somewhat different from that reported by Kurita for A. asiatica.
A PLEOMORPHIC PARASITE OF CEREAL SEEDS, PYRENOPHORA SEMENIPERDA
Authors: Shoemaker R. A.
Published: August 2008

Pyrenophora semeniperda (Brittlebank & Adam) n. comb. (≡Pleosphaeria semeniperda Brittlebank & Adam) (=Pyrenophora horrida H. Sydow) is the ascogenous state of a fungus with three described conidial states. The pycnidial state was not named, but Podosporiella verticillata O'Gara and Bipolaris cyclops (Drechs.) Sprague had been proposed for, respectively, the synnematous and mononematous conditions of the species. The formation of synnemata was found to depend on culture substrate. Consequently, one name, Drechslera verticillata (O'Gara) n. comb., is proposed for the hyphomycetous state. The fungus is redescribed and illustrated from type and other specimens representing records from Australia, Canada, the Republic of South Africa, and the United States of America.
VARIATION IN SHOOT ELONGATION OF PINUS RESINOSA AIT.
Authors: Rehfeldt G. E. , Lester D. T.
Published: August 2008

Shoot elongation and associated phenological and morphological variables were measured and analyzed for an 8-year-old provenance experiment planted in central Wisconsin. Geographic origin of seed significantly affected elongation and all associated characteristics except initiation date of elongation. Lammas growth had a significant effect on the initiation date and termination date of shoot elongation. Rate and duration of elongation contributed about equally to the extent of elongation. Bud length influenced elongation through rate. The pattern of weekly shoot elongation corresponded more closely to weekly mean temperature than to weekly mean precipitation.
ULTRASTRUCTURE OF THE HYPHAE AND HAUSTORIA OF PHYTOPHTHORA INFESTANS AND HYPHAE OF P. PARASITICA
Authors: Ehrlich Mary A. , Ehrlich Howard G.
Published: August 2008

The ultrastructure of the mycelium of both Phytophthora infestans and P. parasitica is consistent with that reported for other Oomycetes. A distinct plasmalemma, porate nuclei, tubular endoplasmic reticulum, mitochondria with tubular cristae, Golgi dictyosomes, and lipid bodies are present within the protoplast. The haustoria produced by P. infestans in the leaves of susceptible potato varieties consist of an expanded haustorial head surrounded by a fungus wall which is continuous with the wall of the intercellular mycelium. The haustorium lacks the long narrow stalk or neck often associated with this organ, and there is considerable cytoplasmic continuity between the haustorium and the intercellular mycelium. All P. infestans haustoria observed were anucleate and generally contained only a few mitochondria and sparse endoplasmic reticulum. The haustorium is enclosed in an encapsulation surrounded by a membrane which is continuous with the host plasmalemma. There is no evidence, around any portion of the haustorium, of a sheath originating from the cell wall of the host. A survey of the current literature on the ultrastructure of the Eumycotinia shows that the parasitic fungi exhibit no unique cytoplasmic features when compared with non-parasitic fungi, and the ultrastructure of the haustoria-producing facultative saprophyte is similar to that of the obligate parasites.
TOXOSPORIOPSIS N. GEN., AN UNUSUAL MEMBER OF THE MELANCONIALES
Authors: Sutton B. C. , Sellar P. W.
Published: August 2008

Toxosporiopsis capitata n. gen., n. sp., collected on bark of Ceiba pentandra (L.) Gaertn., the Kapok tree, in Sierra Leone, is described and illustrated. The fungus is tentatively assigned to the Melanconiales and characterized by versicolored, 3-septate, dark-banded blastospores, each with an apical mucilaginous appendage, and filiform paraphyses which have a mucilaginous sheath. Cylindrical, aseptate, unbranched conidiophores produce a single apical conidium which terminates growth of the conidiophore. It is compared and contrasted with Santiella and related genera.
FUNGI ASSOCIATED WITH NEMATODE AND NON-NEMATODE LESIONS ON BANANA ROOTS
Authors: Stover R. H.
Published: August 2008

Fusarium solani and a binucleate Rhizoctonia were the predominant fungi in nematode and non-nematode lesions on banana roots in Honduras and Panama. In deep lesions of the main root caused by Radopholus similis, F. solani predominated followed closely in prevalence by Rhizoctonia, whereas in shallow lesions of Helicotylenchus multicinctus, Rhizoctonia predominated and F. solani was next in frequency. On necrotic small branch feeder roots Rhizoctonia predominated. In root tip dieback F. solani was the most common, then Cephalosporium and Rhizoctonia. Other fungi obtained in from 5 to 20% of the lesions included F. roseum, Cephalosporium (if tissue was macerated or fragmented before plating), Curvularia, Trichoderma, Penicillium, Nigrospora oryzae, Cunninghamella echinulata, and Botryodiplodia theobromae. Representatives of 14 other genera were inconsistently isolated as well as several nonsporing fungi. Pythium was isolated only once and Phytophthora not at all, even when selective media were used, nor was F. oxysporum encountered. Rhizoctonia and F. solani were also common inhabitants of the surface of healthy banana roots. From 40 to 60% of the Rhizoctonia isolates invaded and often killed seedlings of Musa acuminata and some isolates stunted growth of bananas in pots of methyl bromide fumigated soil. These isolates also produced brown lesions when applied to wounded banana roots growing in a mist chamber. Their contribution to root necrosis and yield decline in banana plantations remains to be determined.
THE ROOT SYSTEM OF LINARIA VULGARIS MILL. II: DIFFERENTIATION OF ROOT TYPES
Authors: Charlton W. A.
Published: August 2008

The relationship has been investigated between stelar diameter, complexity, and the presence or absence of secondary growth in roots of Linaria vulgaris. Diameter and complexity of the primary xylem body were used as parameters. The presence of secondary growth is considered to be a character of roots developing as long roots. The long roots are responsible for the vegetative propagation of the plant. The frequency of occurrence of secondary growth tends to increase both with stelar diameter and complexity, but secondary growth can occur in roots of any size and complexity. Any root appears to be capable of developing as a long root but the larger roots have a greater chance of so doing. It is thought that roots which are developing as long roots inhibit other roots from such development; probably the larger root apices in any given plant are more capable of escaping from or exerting such inhibition.
INVESTIGATIONS OF THE MARINE ALGAE OF NOVA SCOTIA: IV. SPECIES OF CHLOROPHYCEAE NEW OR RARE TO NOVA SCOTIA
Authors: Edelstein T. , McLachlan J.
Published: August 2008

Thirteen species of Chlorophyceae are described, and 12 are new records for Nova Scotia. Pseudopringsheimia confluens (Rosenv.) Wille has been recorded only in Greenland.
PRINCIPAL COMPONENTS ANALYSIS OF DATA FROM SAXICOLOUS BRYOPHYTE VEGETATION AT STEPS BRIDGE, DEVON: III. CORRELATION OF VARIATION IN THE VEGETATION WITH ENVIRONMENTAL VARIABLES
Authors: Yarranton G. A.
Published: August 2008

In the previous papers of this series principal components analysis of data from saxicolous bryophyte vegetation at Steps Bridge was described. The components extracted in the analysis were correlated with environmental variables measured at two physical scales, and the results are reported here. The first two components are associated with shade and with crevices, respectively. The latter components apparently have more complicated relationships with environmental variables and the reasons for this, together with possible improvement of the correlation methods, are discussed.
A STUDY ON THE EPIDEMIOLOGY OF STRIPE RUST, PUCCINIA STRIIFORMIS WEST., IN CALIFORNIA
Authors: Tollenaar H. , Houston Byron R.
Published: August 2008

Stripe rust of wheat, Puccinia striiformis f. sp. tritici, was found to oversummer in the Sierra Nevada at altitudes of 6000 ft or above on wild grasses belonging to Elymus spp., Hordeum spp., and Sitanion spp. The similarity of infection types of stripe rust isolates from various locations and hosts on a differential set of wheat cultivars suggests that only one race of P. striiformis f. sp. tritici occurs in California.Stripe rust on Poa spp. should be considered as P. striiformis f. sp. poae f. sp. nov. because of its entirely different host range and temperature requirements.A mean temperature of 22.3 °C or mean maximum temperature of 32.4 °C measured over a 10-day period is lethal to P. striiformis f. sp. tritici, thus accounting for the absence of this fungus during the summer in all regions of California but the Sierra Nevada and the coastal area. In late autumn, recurrence of the rust in the wheat-growing areas is initiated when east winds carry uredospores from the Sierra Nevada into the central part of the Sacramento – San Joaquin Valley, infecting volunteer wheat plants and early sown wheat. In late winter, a shortening of the latent period because of rising daily temperatures results in a rapid development of stripe rust at these infection sites and consequently in secondary spread of the rust to previously uninfected areas.
DIFFERENTIATION AND MATURATION OF PRIMARY TISSUES IN WHITE MUSTARD ROOT TIPS
Authors: Peterson R. L.
Published: August 2008

Roots of white mustard (Sinapis alba) were grown either on moist filter paper or in aerated or non-aerated water culture, and detailed measurements of rates of tissue differentiation and maturation were made from sectioned and fresh material. The variation in these rates is shown for a number of roots of each treatment and a comparison made between treatments. The sequence of differentiation and maturation of tissues in this root is similar to that reported previously for other dicotyledonous roots. Differentiated and matured tissues were found closer to the apex in slower growing roots, the differences being more pronounced in some tissues between the treatments. This is discussed in relation to the nutrition of the root.
RUTSTROEMIA CUNICULI, A COPROPHILOUS SPECIES OF THE SCLEROTINIACEAE
Authors: Elliott Mary E.
Published: August 2008

A mass-ascospore culture of Coprotinia cuniculi (Boud.) Dennis was grown under controlled environmental conditions and produced mature apothecia. From these apothecia, single-ascospore cultures were isolated and after a growth period of 4 to 5 months they produced mature apothecia. The fungus was shown to be self-fertile. The new combination Rutstroemia cuniculi (Boud.) Elliott is proposed.
THE EFFECT OF DARKENING ON THE SUSCEPTIBILITY OF FRENCH BEAN TO TOBACCO NECROSIS VIRUS
Authors: Kimmins W. C.
Published: August 2008

Darkening of plants of Phaseolus vulgaris var. Prince for 3–108 h before inoculation with tobacco necrosis virus increased the susceptibility of the primary leaves to infection. The maximum number of lesions was obtained when plants were in darkness for 96 h. Darkening produced similar results on detached leaves and decapitated plants. The largest differences in susceptibility between shaded and illuminated plants were found in plants 9–12 days old. In plants 22–24 days old, darkening did not increase susceptibility. When 10-day-old plants were darkened for 24 h, the increased susceptibility that resulted persisted up to 6–8 h after the plants had been returned to light. Short periods (1, 10, and 20 min) of light given at varying times throughout a 24-h period of darkening did not alter susceptibility. Lowering of the light intensity to 250 lumens/ft2 failed to reduce resistance to infection. However, below 250 lumens/ft2 susceptibility increased with decreasing light intensity. Plants in the light or dark were more susceptible when supplied with carbon dioxide free air. When a relative humidity of 20% was used, darkening the plants no longer increased their susceptibility.It is suggested that there are a greater number of infectible sites present in darkened plants, and that this situation may be effected through some aspect of plant water relationships.
PHENOLIC COMPOUNDS IN FERNS: I. A SURVEY OF SOME FERNS FOR CINNAMIC ACID AND BENZOIC ACID DERIVATIVES
Authors: Bohm Bruce A. , Tryon Rolla M.
Published: August 2008

Forty-six ferns, representing 28 genera and 8 families, were examined for hydroxylated cinnamic acids and benzoic acids. In most plants examined the "basic complement" of cinnamic acids, p-coumaric, caffeic, and ferulic, was present. In these plants p-hydroxybenzoic acid, protocatechuic acid, and vanillic acid were generally also present. Of much more limited distribution were sinapic acid, syringic acid, and o-coumaric acid. Coumarin was shown to be present in Dennstaedtia punctilobula, the only fern tested which possessed this type of compound. The data available from three ferns reported in the literature are also included in this survey; one represents an additional family and one represents an additional genus.An experiment with DL-phenylalanine-1-14C and DL-phenylalanine-3-14C and Cyathea arborea showed the incorporation of label into p-coumaric acid, caffeic acid, and ferulic acid.
THE MALE GAMETOPHYTE OF ZEA MAYS L.: III. THE INFLUENCE OF TEMPERATURE AND CALCIUM ON POLLEN GERMINATION AND TUBE GROWTH
Authors: Cook F. S. , Walden D. B.
Published: August 2008

Corn pollen germination on an aqueous medium containing sucrose, calcium, boron, and 1% methyl cellulose produced tubes which attained growth rates of 12 μ/min at 30 °C. After 30 to 60 min they fell to about half this value. Rates of elongation in the early stages of growth increased with a Q10of 2 between 12 and 30 °C. The time required for the initiation of germination is a hyperbolic function of temperature. Maximum germination occurred at 20–23 °C; maximum rate of elongation during the first hour at 30–33 °C.Only a trace of germination occurred below 50 p.p.m. CaCl2∙2H2O and maxi mum at 250–300 p.p.m. Calcium levels had no effect on the time of initiation of germination, on the rate of elongation at 30 °C nor on the mean tube lengths after 30 min and 60 min of germination. A "population effect" was evident on the aqueous medium and was more pronounced at low levels of calcium.Two types of tests produced no evidence of a chemotropic response of pollen tubes to a calcium gradient. Pieces of style and endosperm also gave negative results. The pollen tube growth rates and lengths attained indicate that we are not yet able to control the factors for sustained growth. Some possible factors are discussed.
MINERAL NUTRITION OF CACAO (THEOBROMA CACAO L.).COMPARISON OF PLANT GROWTH AND NUTRIENT CONTENT OF LEAVES OF SIX C.R.I. VARIETIES GROWN IN OPTIMUM AND DEFICIENT CONDITIONS IN SAND CULTURE
Authors: Lockard R. G. , Asomaning E. J. A.
Published: August 2008

The early growth of six cacao varieties important in the breeding program of the Cocoa Research Institute was investigated in sand cultures supplied with optimum and deficient levels of plant nutrients. The varieties tested were the Amazon selections Nanay (Ny) and Parinari (Pa), West African Amelonado (A), and their hybrids, NyA, PaA, and NyPa. Varieties Ny, NyA, and NyPa had similar growth patterns and were the fastest growing; varieties PaA and Pa were similar and the next best; and A was the slowest growing. In the control solutions variety Pa was larger than variety A, but in all deficient nutrient treatments except the calcium-deficient one, the two varieties grew to equal size.Nutrient levels in the leaves did not vary greatly between varieties, and apparently were not correlated with plant growth. The larger, more vigorous varieties had a higher percentage of small lateral absorbing roots than did the less vigorous varieties.The Amazon varieties Ny and Pa grew significantly less in the potassium-deficient nutrient solution than did the Amelonado variety A when compared with their controls. In addition, the symptoms of potassium deficiency exhibited by the Amazon varieties were more severe than those of the Amelonado variety.
CORRELATION OF PHOTOPERIOD WITH TUBERIZATION AND SUSCEPTIBILITY OF POTATO TO VERTICILLIUM ALBO-ATRUM
Authors: Busch L. V. , Edgington L. V.
Published: August 2008

Photoperiod was found to control both initiation of tubers and susceptibility of potato to Verticillium wilt. Plants grown in a short-daily photoperiod (long dark period) formed tubers and such plants, when inoculated with Verticillium albo-atrum, developed moderate to severe wilt symptoms. Plants grown in a long-daily photoperiod did not form tubers and developed no disease symptoms when inoculated with Verticillium. When a 2-hour light period was interjected in the middle of the long dark period, no tubers were formed and plants developed no symptoms of disease when inoculated with Verticillium. The resistance to Verticillium exhibited by plants was not limited to the root but was present throughout the plant.
UPTAKE AND METABOLISM OF INDOLEACETIC ACID, NAPHTHALENEACETIC ACID, AND 2,4-DICHLOROPHENOXYACETIC ACID BY PEA ROOT SEGMENTS IN RELATION TO GROWTH INHIBITION DURING AND AFTER AUXIN APPLICATION
Authors: Andreae W. A.
Published: August 2008

Growth inhibition by applied indoleacetic acid (IAA), naphthaleneacetic acid (NAA), or 2,4-dichlorophenoxyacetic acid (2,4-D) was studied using change in fresh weight of pea root segments as the criterion of growth. Auxin metabolism of these tissues was investigated with 14C-labeled auxins applied under conditions similar to those used in the growth studies.Growth inhibition by applied auxins is independent of the rate of auxin uptake, accumulation of auxin or auxin metabolites in the tissues, or the subsequent loss of accumulated auxin from the tissues. It is also independent of the metabolic processes leading either to auxin conjugation with aspartic acid or to decarboxylation. All three auxins inhibit growth to a similar degree, which depends only on the concentration of auxin applied and the pH of the solution. Inhibition persists undiminished as long as the auxin is applied. It is suggested that growth inhibition by applied auxin occurs at a site external to the cytoplasm, i.e. the cell wall or the cytoplasmic membrane.Growth inhibition of tissues after auxin treatment has ceased is not due to the auxin remaining in the tissues but rather to the auxin released from the tissues to the solution to which they have been transferred. Untreated tissues incubated in the same transfer solution with treated tissues are equally inhibited. The persistence of growth inhibition after treatment depends upon the ability of the tissues to convert accumulated auxins to physiologically inactive metabolites. Conjugation with aspartic acid accounts for the inactivation of all the accumulated NAA metabolized and the major part of the IAA. IAA decarboxylation under these conditions plays a lesser role. Growth recovery following treatment with IAA or NAA occurs as these auxins are metabolized. 2,4-D is not metabolized to any appreciable extent during these studies, and tissues remain inhibited to a degree consistent with the concentration of 2,4-D in the transfer solution.
EFFECT OF TEMPERATURE ON THE GROWTH OF WHEAT: I. MARQUILLO, KENYA FARMER, AND TWO DWARF PROGENY
Authors: Canvin David T. , Yao Yun-Te
Published: August 2008

Wheat varieties, Marquillo, Kenya Farmer, wheat dwarf 1 (Marquillo × Kenya Farmer), and wheat dwarf 2 (Marquillo × Kenya Farmer) were grown in growth cabinets under continuous light at an intensity of 1200 ft-c and temperatures of 16, 21, 26, and 31 °C combined in all possible combinations for 16-h and 8-h periods in a 24-h cycle.Wheat dwarf 1 elongated and produced seed only when soil and air temperature was kept at 26 °C or higher. If the plants were exposed to 21 °C or less for 8 h or longer, only a "grass-clump" habit of growth was observed. At still lower temperatures only a small primary tiller was produced. Wheat dwarf 1 plants, initially grown at 21 °C for 30 days or longer, would not grow and head when transferred to 31 °C. Plants initially grown at 31 °C did not continue to grow when transferred to 21 °C. Wheat dwarf 2 required a temperature of 21 °C or higher to induce elongation. At lower temperatures plants were dwarfed but fertile tillers were produced. Only at 16 °C was a "grass-clump" habit of growth observed.In contrast to the dwarfs, the tallest plants of Marquillo and Kenya Farmer were produced at the lowest temperatures and maximum yield of shoot and seed was obtained under a regime that would be equivalent to a continuous temperature of 17–20 °C.
THE UPTAKE AND DISTRIBUTION OF 32P BY BEAN SEEDLINGS (PHASEOLUS VULGARIS) GROWING AT TWO PHOSPHATE LEVELS, AND SOME EFFECTS OF 2,4-D
Authors: Etter Harold M.
Published: August 2008

The uptake and subsequent distribution of 32P among the root, stem, and leaf tissues of bean seedlings growing in complete or phosphate-free nutrient and its incorporation into organic phosphorus fractions was studied. Plants growing in complete nutrient took up, retained, translocated, and incorporated less activity than those growing in phosphate-free solution. These results are discussed in relation to phosphate pools which appear to be present in bean seedlings. Fifty and 70 h after spraying with 5 p.p.m. 2,4-dichlorophenoxyacetic acid (2,4-D), no marked changes were observed in the uptake or distribution pattern of the 32P as compared to controls.
REACTIONS OF LODGEPOLE PINE TO ATTACK BY DENDROCTONUS PONDEROSAE HOPKINS AND BLUE STAIN FUNGI
Authors: Reid R. W. , Whitney H. S. , Watson J. A.
Published: August 2008

The reaction in lodgepole pine in response to attack by Dendroctonus ponderosae and subsequent infection by blue stain fungi varies with the degree of resistance manifested by the tree. In both resistant and successfully attacked trees a sequence of changes, which increase in space with time, occurs in the inner bark and sapwood. In resistant trees a condition termed secondary resinosis develops which is lethal to bark beetle broods and blue stain fungi. In contrast, successfully infested trees do not exhibit secondary resinosis, and bark beetle broods and blue stain fungi survive and complete their development. In resistant trees blue stain fungi are responsible, directly or indirectly, for the extensive reaction and condition of secondary resinosis which is associated with the insect gallery. Changes in stem tissues associated with wounding are discussed.
THE GROWTH OF EXCISED LEAVES OF MARSILEA
Authors: Gaudet John J.
Published: August 2008

Excised young submerged leaves of Marsilea vestita grew to sizes comparable to that reached on intact plants and lived for approximately 20 days if supplied with auxin and coconut water in a liquid medium.
ENVIRONMENTAL CONTROL OF BUD AND RHIZOME DEVELOPMENT IN THE SEEDLING OF AGROPYRON REPENS L. BEAUV.
Authors: McIntyre G. I.
Published: August 2008

The effects of various environmental conditions on bud development in seedlings of Agropyron repens L. Beauv. were investigated. The bud in the axil of leaf 1 was the most responsive. At a high nitrogen level (315 p.p.m.) most of the buds at this position developed as tillers, and at a low level (2.1 p.p.m.) as rhizomes. A transition from rhizome to shoot development was induced by increasing the nitrogen supply after the rhizomes were initiated. Temperature had a similar effect, tillers being produced at a high (day) temperature (27 °C) and rhizomes at a low temperature (10 °C). Reducing the daylength from 18 to 9 h strongly promoted tillering and almost completely prevented rhizome development. A reduction of light intensity from 4000 to 2000 ft-c did not affect bud development but appeared to increase the tendency for rhizomes to form a terminal shoot. Similar effects were shown by the buds at the coleoptile and leaf 2 positions but the inherent tendency for the former to develop as rhizomes and the latter as tillers limited their response.There was some evidence from these results that bud and rhizome development is controlled by a similar mechanism and that the carbohydrate level may be an important factor in determining the inherent pattern of bud development.
THE TEMPERATURE COEFFICIENT OF INVERTASE FROM THE LEAVES OF COLD-HARDENED AND COLD-SUSCEPTIBLE WHEAT PLANTS
Authors: Roberts D. W. A.
Published: August 2008

The energy of activation of invertase in crude juice and in preparations purified by ammonium sulfate precipitation from winter wheat, Kharkov 22 MC, leaves grown at 6 °C, is lower than that in preparations from similar leaves grown at 20 °C. When Rescue wheat leaves are used the same value for the energy of activation of invertase is obtained whether plants are grown at 6 °C or 20 °C. In this respect Thatcher wheat appears to be intermediate between Kharkov 22 MC and Rescue. Some implications of these observations in relation to cold hardening are discussed.
ON THE STRUCTURE AND ORIGIN OF THE SEEDLING OF PSITTACANTHUS SCHIEDEANUS (LORANTHACEAE)
Authors: Kuijt Job
Published: August 2008

The vascular structure of the ovary and seedling of Psittacanthus schiedeanus (Loranthaceae, sensu stricto) is described, followed by a brief sketch of the unique suspensor and its relationship to the developing embryo. The proembryo and suspensor at first form a single, massive body of which the embryonic pole is a meristem producing the cotyledons. The suspensor portion of this body at its maximum development consists of approximately 2000 cells, but is later crushed by the expanding embryo, and remains as a cup-like envelope of the radicular pole. The embryo itself appears to be unique among dicotyledons in being polycotylous. The functional significance of the suspensor body, and the possible systematic implications of these various aspects are briefly discussed.
ELECTRON MICROSCOPY OF UREDOSPORES OF MELAMPSORA LINI AND OF RUST-INFECTED FLAX
Authors: Manocha M. S. , Shaw Michael
Published: August 2008

Thin sections of germinated and ungerminated uredospores of the flax rust fungus (Melampsora lini (Pers.) Lev.) and rust-infected cotyledons of flax (Linum usitatissimum L., variety Bison) were examined in a Philips 100B electron microscope. The line structure of the mature uredospores, the formation of germ tubes including the development of cross walls, and of the intercellular mycelium, haustoria, sporogenous hyphae, and developing uredospores are all briefly described. Germinated and ungerminated uredospores were fixed in KMnO4 followed by OsO4 at room temperature. Infected tissue was fixed in KMnO4 at room temperature or in glutaraldehyde at 4 °C followed by OsO4 at 4 °C. Nucleoli were not observed in the nuclei of mature uredospores or germ tubes but were present in the intercellular mycelium, sporogenous hyphae, and developing uredospores and were particularly prominent in the two haustorial nuclei. The results are discussed and attention is drawn to the need for further work on the nuclei and nucleoli in germinating uredospores under conditions conducive to the development of infection structures.
HISTOCHEMICAL STUDIES ON THE ALTERATION OF LIGNIN AND PECTIC SUBSTANCES IN WHITE ELM INFECTED BY CERATOCYSTIS ULMI
Authors: Gagnon Camilien
Published: August 2008

Histochemical tests were performed on sections from 3- and 4-year-old seedlings of white elm (Ulmus americana) artificially inoculated with Ceratocystis ulmi in studies on alteration of lignin and of pectic substances following infection. Results showed more intense reactions to tests for lignin and pectins in sections from diseased elms than in sections from healthy elms. Lignin and pectin positive materials were found in vessel plugs. It is suggested that these alterations of lignin and pectins result from the action on cell walls of pectolytic enzymes produced by the pathogen.
CONTROL OF UNICELL FORMATION IN A SOIL SCENEDESMUS
Authors: Trainor Francis R. , Roskosky Frances G.
Published: August 2008

Scenedesmus culture 16, a pleomorphic soil alga, produced colonies resembling S. quadricauda, S. longus, S. abundans, S. bijugatus, and S. acutiformis when grown in stationary flasks in three standard laboratory media. The unicell population was always low under such conditions.When transferred daily in several media containing ammonium ions and buffered at pH 8.5 or above, a unicell population was formed; no coenobia were present. The unicells had delicate spines randomly placed over the cell surface and resembled the genus Franceia. Co-action of other ions in the medium with the ammonium could not be demonstrated. Stored media with Tris buffer showed a steady decline in pH.
INFLUENCE OF ROOT PRUNING ON HEIGHT INCREMENT AND ROOT DEVELOPMENT OF OUTPLANTED SPRUCE
Authors: Sutton R. F.
Published: August 2008

Three-year-old seedlings of Picea glauca and P. abies were outplanted in a fertile silt loam soil at Ithaca, New York, in a split-plot randomized block experiment involving large- and small-size classes of stock and four root-pruning treatments: control; laterals pruned to 5 cm; all roots pruned at 10 cm measured from the root collar; and all laterals pruned flush with the tap or main root.Survival was good except in the last treatment. First- and second-year height increments within each species were unaffected by root-pruning treatments, even the most extreme. This suggests that either water stress is not aggravated by root pruning or that root pruning has compensating advantages. In the second year, height increment of P. glauca was significantly inferior to that of the first year. Height increment of P. abies was significantly greater in the second than in the first year.Root systems of 20 P. glauca were excavated in the second year. Percentage increases of total root length (of all roots 1 cm or more long) in root-pruned trees were twice those of control trees. Highest values (> 1000%) were for vigorous trees in the moderate root-pruning treatments.
VARIATION IN CONE PRODUCTION OF RED PINE IN RELATION TO WEATHER
Authors: Lester D. T.
Published: August 2008

Variation in annual counts of 2-year-old cones was studied in 15-year records from 78 trees scattered over northern Wisconsin. For a 3-year period, 1-year-old cones were also counted and compared with the counts of 2-year-old cones in the following year. In addition to major losses of 2-year-old cones to insects, an average loss of 60% was noted between the 1st and 2nd year of cone development. Counts of 2-year-old cones nevertheless reflected the relative magnitude of the 1-year-old cone crop and thus were presumed to reflect the relative magnitude of the cone crop initiated 24 months before counting.Simple correlations of weather variables with counts of 2-year-old cones were computed for each of the 54 months before counting. Both April mean temperature and July–September mean temperature 2 years before counting were positively associated with variation in cone counts while potential cone crop already present was negatively associated. The use of three variables in multiple regression analysis revealed the predominant influence of July–September temperature and accounted for from 64 to 77% of the variance in counts of 2-year-old cones. Five correlations with less apparent biological explanation also were detected.
LIVING HAUSTORIA AND HYPHAE OF ERYSIPHE GRAMINIS F.SP. HORDEI WITH INTACT AND PARTLY DISSECTED HOST CELLS OF HORDEUM VULGARE
Authors: Bushnell W. R. , Dueck J. , Rowell J. B.
Published: August 2008

Erysiphe graminis DC f.sp. hordei Em. Marchal was grown on the inner epidermis of the coleoptile of barley (Hordeum vulgare L.) in mounts that permitted microscopic observation and treatment of living cells of both host and parasite. Growth rates of the mildew fungus on partially isolated single layers of epidermis from coleoptiles equaled rates on intact green leaves 48–72 h after inoculation when the colonies elongated by 14–17 μ/h. The colonies often grew at approximately normal rates for 3–6 h after the protoplasts of parasitized host cells were destroyed by dissection, with the single haustorium of the colony exposed to artificial ambient media. The most prolonged growth occurred when the contents of the host cell were replaced with solutions that were hypertonic with respect to the host (0.5–0.6 M sucrose). Haustoria in contact with hypertonic media were normal in uptake of neutral red, in apparent turgidity, and in the position of the haustorial sac closely affixed to the body of the haustorium. Removal of this single haustorium stopped hyphal growth immediately, but growth often resumed after 3–24 h and then continued for 5–24 h at rates [Formula: see text] to [Formula: see text] of the normal rate without formation of new haustoria. Microbial contamination prevented the assessment of the capabilities of mildew hyphae for growth over long periods after dissection of host cells. The results suggest, however, that haustoria exposed by the present techniques are functional and therefore might be used to investigate the nature of uptake and secretion by these structures, but that the haustorium is not essential for short periods of hyphal growth by E. graminis f.sp. hordei.
THREE-YEAR EFFECTS OF SYSTEMIC FUNGICIDES APPLIED FOR THE CONTROL OF CYTOSPORA IN ITALIAN PRUNE TREES
Authors: Helton A. W. , Kochan W. J.
Published: August 2008

Forty-eight 20-year-old Italian prune trees (Prunus domestica) in a commercial orchard were treated (controls excepted) during 1964. Each tree bore multiple infections with Cytospora cincta at the time of treatment. The trees were spray-treated with 5000 p.p.m. of 8-quinolinol benzoate, Phytoactin L-456, or CTS (cycloheximide thiosemicarbazone) in 1964 but not thereafter. By means of canker measurement, the effects of these treatments were followed through September, 1966.The results showed that all three materials provided significant reductions in canker-expansion rate during the 3-year period; that CTS was superior to Phytoactin and 8-quinolinol benzoate; that CTS caused near halting of canker expansion and provided increases in yield; and that the effects of these compounds were almost as great at the end of the 3-year period as at the end of the year of treatment.
OZONE DAMAGE AND SEMIMATURE-TISSUE NEEDLE BLIGHT OF EASTERN WHITE PINE
Authors: Linzon S. N.
Published: August 2008

Investigations were conducted in forests remote from large urban areas to determine whether there was any cause and effect relationship between naturally occurring atmospheric ozone (O3) and semimature-tissue needle blight (SNB) of eastern white pine (Pinus strobus). The daily average concentration of atmospheric ozone, relative to cracking by rubber test strips, was determined for three seasons and no apparent relationship was found between excessive rubber cracking and the occurrence of outbreaks of SNB on susceptible white pines. The repeated application of vitamin C, a reducing agent, to newly developing needles of susceptible white pines, did not prevent the appearance of the symptoms of SNB or retard subsequent symptom development. In fumigation experiments with artificially produced ozone, concentrations of over 0.60 p.p.m., as measured by the manual potassium iodide method, or 0.40 p.p.m. by the coulometric method, were required to produce severe markings on the new needles of the white pine under study. Foliage on material derived from trees non-susceptible to SNB was more responsive to these high concentrations of ozone and exhibited more uniform damage than foliage derived from trees susceptible to SNB. The macroscopic and microscopic symptoms of damage caused by excess ozone were dissimilar from the typical symptoms of SNB. The results of these investigations indicate that naturally occurring atmospheric ozone in stands of eastern white pine is not an incitant of SNB.
AN ANALYSIS OF DRY MATTER PRODUCTION OF DOUGLAS-FIR SEEDLINGS IN RELATION TO TEMPERATURE AND LIGHT INTENSITY
Authors: Brix Holger
Published: August 2008

Seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were grown in growth chambers under all combinations of three temperatures (13, 18, and 24 °C) and three light intensities (450, 1000, and 1800 ft-c). Dry matter production of leaves, stem, and roots was determined at 65 and 100 days after germination. The leaf area produced per unit of leaf dry weight and the dry matter distribution to the plant organs was measured. Net assimilation rates between the ages of 65 and 100 days were calculated. Rates of photosynthesis per unit of leaf were determined at different light intensities and temperatures, and rates of respiration of plant top and of roots were found for different temperatures.Increasing light intensity affected dry matter production in two opposing ways: (i) it increased the rate of photosynthesis per unit leaf area, and (ii) it decreased the leaf area added per unit of dry matter produced. A pronounced increase in growth with increase in temperature from 13 to 18 °C was a result of a temperature influence on production of leaf area rather than the effect of photosynthesis per unit of leaf. Net assimilation rates decreased with increase in temperature at all light intensities.
THE FINE STRUCTURE OF VESICLES ASSOCIATED WITH THE CELL SURFACE IN HELIANTHUS SHOOT TISSUE
Authors: Walker Waldo S. , Bisalputra T.
Published: August 2008

The fine structure of vesicles which were observed in association with the cell surface of shoot tissue of Helianthus annuus is described. These unit membrane-bound vesicles, which were up to 2 μ in diameter, contained tubules and occurred in several tissues of the shoot. They were present deep within the cytoplasm, as well as in close association with the cell wall, where they fused with the plasmalemma and appeared to empty their contents in the vicinity of the wall. These vesicles are compared to similar structures described by other investigators. The possible relationship of these structures to deposition of cell wall materials is discussed.
MAJOR AND MINOR GENES IN WHEAT FOR RESISTANCE TO PUCCINIA STRIIFORMIS AND THEIR RESPONSES TO TEMPERATURE CHANGES
Authors: Lewellen R. T. , Sharp E. L. , Hehn E. R.
Published: August 2008

The wheat varieties, 'P.I. 178383' and 'Chinese 166' (Triticum aestivum), were each found to carry an incompletely dominant major gene for resistance to a single pathogenic type of Puccinia striiformis. In addition, an undetermined number of minor genes segregated in such a way that in certain combinations they conferred moderate resistance and modified the action of the major genes. The rust readings were made on seedling plants grown in strictly controlled-environment chambers that simulated natural conditions. The action of the major genes was not affected by different temperature profiles, but the minor genes gave better resistance at a higher temperature profile than at a lower temperature profile.
THE IN VITRO GROWTH OF ACER SACCHARUM AND ACER PENNSYLVANICUM CALLUS TISSUE
Authors: Mathes Martin C.
Published: August 2008

The media and conditions for the growth of isolated maple tissues were determined. Tissues isolated from Acer pennsylvanicum and Acer saccharum were grown on a medium containing 25% coconut milk, 2 p.p.m. naphthalene-acetic acid, 2% sucrose, and 2 times the salt concentrations suggested by White and Nitsch. The cultures have maintained an actively growing condition in the dark at 26–27 °C. The utilization of various carbohydrates by A. pennsylvanicum tissue was determined. Sucrose, glucose, and raffinose were utilized most efficiently. Extracellular starch digestion was detected using isolated A. saccharum stem callus.
THE AUTOECIOUS SPECIES OF PUCCINIA ON HELIANTHEAE IN NORTH AMERICA
Authors: Parmelee J. A.
Published: August 2008

Sixty-two taxa are recognized in this study of the species of Puccinia completing their life cycle on Heliantheae. Six new species are described: Puccinia guatemalensis Parmelee on Zexmenia spp. and Wedelia spp., P. ghiesbreghtii Parmelee on Wedelia ghiesbreghtii, P. abramsii Parmelee on Geraea viscida (= Encelia viscida), P. chloracae Parmelee on Viguiera spp., P. calanticariae Parmelee on Viguiera spp., and P. praetermissa Parmelee on Lagascea spp. Six new varieties are recognized: Puccinia electrae var. robusta Parmelee and P. electrae var. depressiporosa Parmelee on Zexmenia brevifolia, P. caleae var. cuernavacae Parmelee on Calea spp., P. cognata var. echinulata Parmelee on Verbesina spp., P. cognata var. fraseri Parmelee on Viguiera fraseri, and P. affinis var. triporosa Parmelee on Viguiera spp. Three taxa have been restored from synonomy under P. abrupta, viz. P. subglobosa, P. ximenesiae, and P. affinis, the last two parasitic on Verbesina spp., the first on Rhysolepis (= Viguiera). P. tithoniae, P. nanomitra, and P. ordinata, are reduced to synonomy with P. enceliae var. enceliae, P. iostephanes, and P. melampodii respectively. New combinations include: P. enceliae var. aemulans (Syd.) Parmelee and P. abrupta var. partheniicola (Jacks.) Parmelee. A key based on uredinial and telial characters, others based initially on the hosts, and a host index are provided. Each taxon is illustrated by a photomicrograph from type material. Distribution and host extensions, supplementary to those given in Arthur's Manual of the Rusts, are indicated.
The ultrastructure of zoospores of Phytophthora megasperma var. sojae
Authors: Ho H. H. , Zachariah K. , Hickman C. J.
Published: August 2008

The zoospore of Phytophthora megasperma var. sojae is bounded by a unit membrane. Ribosomes, mitochondria, and vesicles with amorphous or crystalline contents occur throughout the zoospore with the exception of the groove region which is characterized by the presence of microtubules, transversely striated elements of unknown nature, and a large vacuole. The flagella, with typical 9 + 2 fibril arrangement, are inserted on a small ridge which lies across the groove. Conspicuous rough endoplasmic reticulum is present in the form of bands around the nucleus and in the cytoplasm. Interspersed amongst the vesicles, just below the surface of the zoospore, are some bodies resembling microbodies or spherosomes.
Evidence for lack of relationship between Canadian cucumber necrosis and tobacco necrosis viruses
Authors: Dias Humberto F. , Doane Frances W.
Published: August 2008

Serological comparisons between the Canadian cucumber necrosis virus (CNV) and a tobacco necrosis virus (TNV) isolated in Ontario showed that these viruses are unrelated. Differences in particle size (CNV = ca. 31 mμ; TNV = ca. 26 mμ) and sedimentation constant (CNV = S20 w 133; TNV = S20 w 116) also distinguish them.