bluuebunny/crossref_metadata_2025 huggingface dataset:
Leaf rust resistance of some European varieties of wheat
Authors: Bartoš P. , Samborski D. J. , Dyck P. L.
Published: September 2008

Twenty-one European wheat varieties from the World Wheat Assortment in Prague-Ruzynĕ (Czechoslovakia) that were resistant to leaf rust were tested with Canadian leaf rust races 1, 5, 9, 11, 15, 30, 58, and 126. The patterns of rust reaction and genetic studies on representative varieties suggest that the varieties Belocerkovskaja 198, Bezostaja 1, Mironovskaja 264, Mironovskaja 808, Osetinskaja 3, Rannaja 12, Skorospelka 3b, Fertödi 293, and Sládkovičovo K 1004 have gene Lr3, the variety Halle 9H39 has gene Lr1, the varieties Erythrospermum 142, 953, and 974 I.Z.R. have genes Lr1 and Lr3, and the variety Etoile de Choisy gene Lr16. The other varieties tested (Flevina, Sambo, Stabil, Uhčetice 22/IV, and 22/V) have reactions that are different from any of those of the single gene lines tested. The varieties Weique and Salzmünder Bartweizen were resistant to all races tested.
Procedures and media for obtaining tissue cultures of 12 conifer species
Authors: Harvey A. E. , Grasham J. L.
Published: September 2008

Procedures for obtaining axenic tissue cultures of Abies grandis, Larix occidentalis, Picea abies, Picea engelmanni, Picea pungens, Pinus albicaulis, Pinus contorta, Pinus flexilis, Pinus nigra, Pinus ponderosa, Pseudotsuga menziesii, and Thuja plicata are described. All species were cultured on a basal medium containing calcium nitrate, magnesium sulphate, potassium phosphate (monobasic), ammonium sulfate, ferric sulfate, manganese sulfate, glucose, 0.8% Bacto agar, and one of three auxins (indoleacetic acid (IAA), naphthaleneacetic acid (NAA), or 2,4-dichlorophenoxyacetic acid (2,4-D)) at various concentrations. Growth of most species was further enhanced by the addition of several vitamins and amino acids. These species were relatively specific in their auxin requirements. The type of sterilant (H2O2, NaOCl) and manipulation required in the preparatory procedures were also specific for individual species.
Organic compounds in cold-water extracts of grand fir heartwood
Authors: Kasper James B.
Published: September 2008

Cold-water extractives of grand fir, Abies grandis (Dougl.) Lindl., heartwood yielded pinitol, sequoyitol, and a compound containing a ketone group. No other organic chemicals were extracted.
Investigations of the marine algae of Nova Scotia.: VI. Some species new to North America
Authors: Edelstein T. , McLachlan J.
Published: September 2008

One species of Chlorophyceae, one species of Phaeophyceae, and six species of Rhodophyceae, collected in Nova Scotia, are recorded for the first time from North America.
Tissue culture from bulbil of Dioscorea sansibarensis
Authors: Rao A. N.
Published: September 2008

The bulbil tissue of Dioscorea sansibarensis Pax., a monocot, was grown in vitro; some aspects of the growth and organogenesis are described here. The tissue, chiefly storage parenchyma, grows into callus on White's medium supplemented with coconut milk and 2,4-D. Kinetin and indoleacetic acid had no effect at the concentrations tested. Roots usually developed in 4- to 5-month-old cultures. Bud initials developed in about 2% of the 6-month-old cultures. The present results are compared with the previous literature concerned with the growth of storage tissues in culture, including the few reports for monocots.
Influence of soil temperature on the development of pea root rot
Authors: Benedict W. G.
Published: September 2008

Pisum sativum vars. Early June, Early Sweet, and Sweet were grown in five root-rot soils and a sterilized control soil maintained at 28°, 26°, 24°, 22°, 18°, 16°, 14°, and 10 °C. Light intensity, day length, and soil moisture were kept constant. Data were recorded from seeding to mature plant development on loss of seed weight, gain in plant weight and height, losses due to preemergence killing and postemergence wilting, lesioning on the subterranean part of the epicotyls, and the fungi and nematodes found associated with the diseased tissues. Results showed that soil temperature generally, with distinct exceptions, had a definite influence on the growth of the peas, according to varieties, in the root rot soils. One fungus predominated as the causal agent of root rot for each variety: Fusarium spp. for var. Early June, which was highly tolerant to root rot soil, and Rhizoctonia solani for Early Sweet and Sweet, which were later maturing varieties. Pythium spp. was also involved in the root rot. The number of seedlings lost as a result of preemergence killing showed greater variation in relation to pea variety and root-rot soil than soil temperature, but postemergence wilting was correlated more closely with soil temperature. The variety Early Sweet was so susceptible to root rot over a wide range of soil temperatures as to preclude its general use in pea-growing areas.
In vitro morphogenesis in Osmunda cinnamomea. The role of the shoot apex in early leaf development
Authors: Hicks G. S. , Steeves T. A.
Published: September 2008

In sterile nutrient culture, shoot apices of the rhizome of Osmunda cinnamomea L., devoid of all visible foliar primordia, quickly give rise to dorsiventral leaf primordia at a presumptive leaf site (I1). It was established that these primordia were irreversibly determined as leaves. To examine the morphogenetic role of the shoot apex in governing early leaf development, this site was permanently isolated from the shoot apex by a single tangential cut. Usually, radially symmetrical shoots of indeterminate growth arose at I1 as a result of this surgery. By contrast, when organic continuity between I1 and the shoot apex was only temporarily interrupted by a cut which was subsequently allowed to heal, normally oriented dorsiventral leaf primordia formed most frequently at I1. These, too, were determined as leaves. It was concluded that the shoot apex serves as a source of determinative influences for the nascent primordium, imposing dorsiventrality and a pattern of determinate growth on the leaf site.
Structural relations between nucleus and cytoplasm during mitosis in Nicotiana tabacum mesophyll
Authors: Esau Katherine , Gill Robert H.
Published: September 2008

The changes in relation between the nucleus and the cytoplasm associated with mitosis were explored at the ultrastructural level in the mesophyll of Nicotiana tabacum L. The material was fixed in glutaraldehyde – formaldehyde – osmium tetroxide. During interphase and early prophase the nucleoplasm can be distinguished from the cytoplasm by its lack of granules comparable to those interpreted as ribosomes in the cytoplasm. After the nuclear envelope is disrupted the nuclear region shows a population of ribosomes identical with that in the cytoplasm, that is, the nucleoplasm and the cytoplasm become indistinguishable. The nuclear envelope differs from the endoplasmic reticulum located in the cytoplasm by the presence of pores. Pieces of the disrupted nuclear envelope assume the same appearance as the endoplasmic reticulum although they remain localized around the nuclear region until metaphase. Eventually the remnants of the envelope are carried to the spindle poles and serve as a source of envelopes for the daughter nuclei. The larger organelles are excluded from the nuclei during development of their envelopes but units of endoplasmic reticulum and apparently some cytoplasmic ribosomes become trapped among the chromosomes. Later, the extranuclear components disappear, probably by being disassembled.
The role of sclerotial rind in the germinability of sclerotia of Sclerotium rolfsii
Authors: Chet I.
Published: September 2008

Punctured sclerotia of Sclerotium rolfsii Sacc. germinated more rapidly than unpunctured ones, especially on water agar. Discs of agar with mycelium and sclerotia in different stages of development were transferred to medium supplemented with 14C-iodoacetic acid. The radioisotope was not incorporated into mature sclerotia. It was concluded that the sclerotial rind is a mechanical barrier preventing uptake of nutrients from the medium.
Light and electron microscope observations of a vacuolar structure associated with the floral apex of Nigella damascena
Authors: Greyson R. I. , Mitchell K. R.
Published: September 2008

Both light and electron microscope observations were recorded of a vacuolar structure which is associated with the onset of flowering in Nigella damascena. This structure has been observed in both chemically fixed and fresh-frozen sections. It is a spherical, occasionally lobed, rough-surfaced structure found in both dividing and non-dividing cells of the corpus and pith – rib meristem of the prefloral and floral apex. Less frequently these structures were located in the cells of the floral organs and occasionally at the tips of young bracts and leaves. The slight differential staining response of these structures suggests some internal differentiation and this is supported by electron micrographs. At least three regions of differing electron density can be recognized. While small pieces of unit membrane can be found attached to the outer surface, this structure is not membrane bound. We suggest that this vacuolar structure represents an accumulation, in the cells of the floral apex, of some synthetic product which is ultimately used by the cells of the flower.
Type studies of Coniella, Anthasthoopa, and Cyclodomella
Authors: Sutton B. C.
Published: September 2008

The history of the generic names Coniella Höhn., Anthasthoopa Subram. & Ramakr., and Cyclodomella Mathur, Bhatt & Thirum. is briefly reviewed. Five species are accepted in Coniella, including C. musaiaensis n. sp. from Bauhinia reticulata DC., and C. simba (Subram. & Ramakr.) n. comb. (≡ Anthasthoopa simba Subram. & Ramakr.). Cyclodomella nigra Mathur, Bhatt & Thirum., the type and only species of Cyclodomella, is tentatively reduced to synonymy with Coniella diplodiella (Speg.) Petrak & Syd. sensu Petrak & Syd.
Forest microfungi. I. Ampulliferina persimplex n. gen., n. sp. on leaves of labrador tea
Authors: Sutton B. C.
Published: September 2008

Ampulliferina persimplex n. gen., n. sp. is described and illustrated from material on moribund leaves of Ledum groenlandicum Oeder collected in Manitoba and Saskatchewan. The fungus is characterized by hyphopodiate superficial mycelia, simple separate unicellular conidiophores each forming an un-branched acropetal chain of cylindrical, brown, 1-septate, truncate conidia. The genus is compared and contrasted with Xylohypha (Fr.) Mason, Septonema Corda, Bispora Corda, Ampullifera Deighton, Clasterosporium Schw., Septotrullula Höhn., Ampulliferella Bat. & Caval., and Ampulliferopsis Bat. & Caval.
Gametophyte formation in bracken fern root cultures
Authors: Munroe Marian H. , Sussex Ian M.
Published: September 2008

Excised roots of the bracken fern (Pteridium aquilinum (L.) Kuhn) have been continuously subcultured in various growth supporting media. The formation of gametophytes on the roots (apospory) occurs in three instances: on intact sporelings in culture, in aged growing root cultures after growth of the roots has ceased, and at an earlier time on excised roots in media lacking carbohydrates. Cells in the outer layers of the root tip become intensely green and form protuberant outgrowths which develop as diploid gametophytes. Addition of ammonium ions, an organic nitrogen source, or kinetin to the culture medium enhances the response.
Resistance of genes isolated from Avena sterilis to isolates of oat crown rust prevalent in Canada in 1968
Authors: Fleischmann George
Published: September 2008

Lines of Pendek each containing a single Avena sterilis gene (Pc-38, Pc-39, Pc-40, Pc-41, and Pc-42) were tested to 116 isolates of Puccinia coronata var. avenae identified in Canada in 1968. None of the isolates attacked gene Pc-39 and only two isolates (races 290 and 326) attacked Pc-38. The other A. sterilis genes were not particularly effective against these crown rust isolates.
Initiation of ovulate strobili in cotyledon-stage seedlings of Pinus elliottii
Authors: Smith W. H. , Konar R. N.
Published: September 2008

Ovulate strobili were initiated at the cotyledon stage of Pinus elliottii Engelm. Only seedlings from 1 of 60 clonal seed sources formed the reproductive structures. One of the seedlings formed an apical and two lateral cones while the other had five lateral cones. Ontogenetic and anatomical study confirmed that the structures were ovulate cones. This is the earliest cone initiation ever observed in pine. Implications are discussed.
Chromosome numbers of some plants from the unglaciated central Yukon plateau, Canada
Authors: Mulligan Gerald A. , Porsild A. E.
Published: September 2008

Chromosome numbers are given for 58 plant taxa of the Yukon Territory, especially from the unglaciated areas in the Ogilvie Mountains. The chromosome numbers of the following taxa were previously unknown: Rumex arcticus Trautv., 2n = 40; Claytonia arctica Adams, 2n = 10; Arenaria arctica Stev., 2n = ca. 80; Arenaria physodes Fisch. ex DC., 2n = 66; Melandrium taylorae (Robins.) Tolm., 2n = 48; Ranunculus gelidus Kar. & Kir., 2n = 16; Ranunculus sceleratus ssp. multifidus (Nutt.) Hult., 2n = 64; Ranunculus purshii Richards., 2n = 64; Thalictrum sparsiflorum Turcz. var. richardsonii (Gray) Boivin, 2n = 14; Chrysosplenium wrightii Franch. & Sav., n = 12 and 2n = 24; Saxifraga adscendens ssp. oregonensis (Raf.) Bacigalupi, n = 11; Saxifraga punctata L., 2n = ca. 84; Saxifraga radiata Small, n = 13; Dryas alaskensis Porsild, 2n = 18; Geum rossii (R. Br.) Sér., 2n = 70; Potentilla ledebouriana Porsild,2n = 28; Oxytropis huddelsonii Porsild, 2n = 16; Epilobium ciliatum Raf., 2n = 36; Penstemon gormanii Greene, 2n = 16; Synthyris borealis Pennell, 2n = 24; Arnica lessingii Greene, 2n = 57.
Growth of the rust fungus Cronartium ribicola in tissue cultures of Pinus monticola
Authors: Harvey A. E. , Grasham J. L.
Published: September 2008

Cambial explants of western white pine, Pinus monticola, infected with Cronartium ribicola, were cultured on a medium containing glucose, calcium nitrate, magnesium sulfate, potassium phosphate (monobasic), ammonium sulfate, ferric sulfate, manganese sulfate, and one of three auxins: indoleacetic acid (IAA), naphthaleneacetic acid (NAA), or 2,4-(dichlorophenyoxy)acetic acid (2,4-D).Invasion of newly formed callus tissue by the rust fungus was generally slow. Dense, feltlike aerial mycelia were frequently produced. Intercellular mycelia and intracellular haustoria were typical, and direct attachments to aerial mycelia were observed. Occasionally, mycelia invaded the medium, but did not become independent of the host tissue. Typical pycnia- and aecia-like sori were produced in many cultures. Aecia-like sori formed immediately after maturation of pycnia, but did not produce spores.
Lamellar lipoprotein of Nicotiana chloroplasts: in vivo incorporation of carbon dioxide, acetate, and leucine
Authors: Bishop Richard S. , Perry Mary J. , Schreiber Richard W.
Published: September 2008

The use of carbon dioxide, acetate, and leucine in the synthesis of lamellar lipoprotein was investigated in chloroplasts of Nicotiana tabacum L. seedlings. These 14C-labelled substrates were fed to sterile seedlings and lamellae were isolated from seedling chloroplasts. The major lamellar lipoprotein was extracted by continuous-flow polyacrylamide gel electrophoresis and the lipoprotein was separated into protein and lipid fractions.All of the substrates were incorporated into both protein and lipid. Carbon dioxide and acetate incorporation was more strongly light dependent than leucine. Light–dark and protein–lipid incorporation ratios were established for each substrate. Leucine label was found in many lamellar amino acids.
Species and varietal differences in the proteins of rapeseed
Authors: Finlayson A. J. , Bhatty R. S. , Christ C. M.
Published: September 2008

Two proteins, previously described by the authors as BI (S020, buffer 12 S) and AIVS (S020, w 1.7 S) have been isolated from eight varieties of rapeseed belonging to Brassica campestris L. and Brassica napus L. species. These proteins have similar chromatographic and electrophoretic characteristics but differ in amino acid composition, particularly with regard to the sulfur-containing amino acids. One of the rapeseed samples was obtained from plants grown on sulfur-deficient soil. The sulfur deficiency produced, in the mature seed, a much reduced protein content and appeared to affect the structure of the protein BI.
Physiological and biochemical studies of adventitious root formation. Extractible rooting cofactors from Hedera helix
Authors: Girouard Ronald M.
Published: September 2008

Physiological and biochemical studies were made of the extractible rooting cofactors from juvenile and mature growth phases of Hedera helix, English ivy. An extraction procedure involving 100, 95, 80, and 60% ethyl alcohol was adopted for general use. The number and concentration of rooting cofactors in the leaves, stems, and roots were determined. Elution of cofactor 4 (oxygenated terpenoids) from a silica gel column, with increasing amounts of ethyl acetate in hexane, resulted in five major fractions and several minor ones. High levels of chlorogenic and isochlorogenic acids were found in all tissues, while traces of caffeic and ferulic acids were detected only in the roots. The decreasing order of plant parts from both growth phases for total chlorogenic and isochlorogenic acids was leaves, roots, and stems; this pattern also applied to total phenol content of the plant parts. Chlorogenic acid was a component of rooting cofactor 2. Rooting cofactor 3 had at least three constituents: chlorogenic and isochlorogenic acids, and an unknown promoter (P-257). The effects of caffeic, chlorogenic, isochlorogenic, and quinic acids with indoleacetic acid in the rooting bioassay were similar and not very large at a concentration of 5 × 10−4 M or lower. No active component of rooting cofactor 1 was identified.
The effect of prolonged seed soaking on seedling growth of Pisum sativum
Authors: Larson L. A. , Lwanga Kyagaba
Published: September 2008

Pea seeds soaked in sterile water for 2 days at 20 °C showed no adverse effects. If seeds are soaked longer seedling development is retarded, roots are shorter, and stem tissue deteriorates. Seeds soaked 2 and 3 days show a maximum rate of root growth in excess of the maximum growth rate exhibited by seeds soaked for 1 day. Increasing the soaking time tends to delay the utilization of stored food in the cotyledon.
An investigation of angle-meristem development in excised stem segments of Selaginella martensii
Authors: Webster T. R.
Published: September 2008

The development of dorsal and ventral angle-meristems in excised Y-shaped stem segments of Selaginella martensii grown on filter paper moistened with distilled water has been investigated. Based on the position of the branchings relative to the shoot tip on the intact plant, segments were designated as young, intermediate, or old. In most segments, with no auxin treatment, ventral angle-meristems formed shoots. In most young segments the dorsal angle-meristem formed a root, whereas most old segments formed a dorsal shoot. A developmental study suggests that (1) in young segments early development of a ventral shoot, controls development of the dorsal angle-meristem as a root, and (2) in old segments where both angle-meristems develop at approximately the same time, there is no ventral control over dorsal development, and a dorsal shoot results. Experiments with externally applied auxin suggest that auxin is an effective factor in controlling ventral angle-meristem development as a root.
The respiratory pathways of tobacco leaves infected with potato virus X
Authors: Dwurazna M. M. , Weintraub M.
Published: September 2008

In an attempt to define the causes for the increased respiration effected by certain strains of potato virus X (PVX) in tobacco leaves, the oxidative and phosphorylative activities of leaf mitochondrial preparations were studied, as well as the hexose and pentose metabolism of cell-free extracts. No difference was found in mitochondrial activities in preparations from healthy leaves and from leaves infected with the severe ringspot strain at the stage of infection when the respiratory increase was maximal. However, in the cell-free extracts from leaves infected with all four strains of PVX, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase showed substantially increased activity compared to those from healthy control leaves. Phosphoriboisomerase activity was less than that in the healthy controls. Comparison of C6/C1 ratios showed a decrease in both inoculated and systemically infected leaves with all four strains. It is concluded that the previously observed increase in the respiration of PVX-infected tobacco leaves is largely connected with an increase in the activities of the enzymes in the pentose phosphate pathway.
Fluctuations in natural soil populations of Verticillium tricorpus
Authors: Taylor J. B.
Published: September 2008

Numbers of V. tricorpus propagules in soil showed considerable variation according to the time of the year when samples were taken. This is considered to be a true fluctuation, rather than chance variation, or periodic suppression by antagonistic fungi, and is in contrast to earlier evidence that the related species, V. albo-atrum and V. dahliae, are present in soil mostly as resting bodies. Instead, it is suggested that the fluctuation in number of propagules is due to microsclerotia producing short-lived spores. Under laboratory conditions it has been shown that conidia and microconidia are produced directly by microsclerotia, and it is suggested that such bodies are responsible for the fluctuation in number of propagules in soils.
Studies on aecial development in rust fungi: Puccinia polliniae
Authors: Singh B. V.
Published: September 2008

The leaves of Goldfussia dalhousiana become infected by Puccinia polliniae with the onset of rains in the Western Himalayas. Pale yellow dots appear on the leaves, developing into pustules and extending centrifugally. Pycnia develop on the upper surface and aecia on the lower. Protoaecia are differentiated into fertile and displacement zones. After dikaryotization, the basal cells elongate, become binucleate, and, by transverse conjugate division, produce the aeciospore mother cells. By transverse division, each of these form a large aeciospore and a small disjunctor cell towards the basal cell. The basal cells at the periphery, by transverse conjugate divisions, give peridial mother cells each of which by an oblique conjugate division cuts off an intercalary cell towards the outside and a peridial cell towards the inside. The peridial cells develop thick walls and the intercalary cells degenerate. The peridium has a dual origin and the aecia are of the aecidioid type. The aeciospores are circular to oval in shape, binucleate, and multiguttulate. They have radially striate thickened walls and two to three germ pores.
Electron microscopy of conidium development and secession in Cryptosporiopsis sp., Phoma fumosa, Melanconium bicolor, and M. apiocarpum
Authors: Sutton B. C. , Sandhu D. K.
Published: September 2008

The ontogeny, delimitation, and release of conidia from annellophores in Cryptosporiopsis sp., Melanconium bicolor, and M. apiocarpum are described in relation to the multilayered structure of conidium and conidiophore walls. Secession is effected by circumcision of an outer periclinal wall common to conidia and conidiophores. A comparison is made with the sequence in Phoma fumosa where limited evidence indicates a similar type of conidium development.
Potebniamyces (Phacidiella) disease of the true firs in British Columbia
Authors: Funk A.
Published: September 2008

Potebniamyces balsamicola Smerlis is shown to be the chief fungus associated with dieback and canker disease of alpine fir (Abies lasiocarpa (Hook.) Nutt.) in British Columbia. Symptoms are described and effects discussed. Girdling cankers were also found in grand fir (Abies grandis (Dougl.) Lindl.) growing in the interior wet belt and in amabilis fir (Abies amabilis (Dougl.) Forb.) growing in the north.
The susceptibility of cereals and wild oats to an isolate of the aster yellows pathogen
Authors: Westdal P. H. , Richardson H. P.
Published: September 2008

Common and durum wheat, oats, wild oats, barley, rye, and Triticale were moderately to highly susceptible to a non-celery-infecting isolate of the aster yellows pathogen (AY) obtained from naturally infected barley in Manitoba in 1966. The isolate produced distinctive symptoms in aster and, on the basis of these symptoms and differential transmission to several hosts, is considered to be different from previously described strains of AY. The susceptibility of Triticale and wild oats appears to be a new record, that of rye and the high susceptibility of oats and some common wheats, new for North America. The high susceptibility of some of these crops to AY appears to be of considerable significance in the spread of the disease.
Studies on Stereum sanguinolentum in Kenya pine plantations
Authors: Griffin H. D.
Published: September 2008

A potentially dangerous decay problem caused by Stereum sanguinolentum (Alb. & Schw. ex Fr.) Fr. was studied over a 2-year period in highland pine plantations in Kenya. Microscopic and cultural comparison between the Kenyan fungus and representative material from the Northern Hemisphere revealed no major differences. S. sanguinolentum was found in pine plantations throughout most of Kenya's highland forest estate but not in Tanzania or Uganda. Of 10 exotic pine species tested, all proved to be suitable substrates for the development of the fungus, though sporophore production was most rapid and abundant on the two major plantation species, Pinus patula Schiede & Deppe and Pinus radiata D. Don. Wounds associated with big-game damage and pruning operations were the usual infection courts. Pruning wound infection rates were as high as 50% during wet weather. Control of infection through pruning wounds could be effected by restricting pruning operations in pine plantations to the dry season. Decay rates and volume losses could not be predicted from data obtained in this study.
Conidium ontogeny in hyphomycetes. The phialides of Phialophora, Penicillium, and Ceratocystis
Authors: Cole G. T. , Kendrick W. B.
Published: September 2008

Phialide and phialospore ontogeny of Phialophora lagerbergii (Melin and Nannf.) Conant, Penicillium corylophilum Dierckx, and the imperfect state of Ceratocystis paradoxa (Dade) Moreau are illustrated by time-lapse photomicrography, and a unified concept of the phialide is derived.
Pectic and cellulolytic enzymes produced by Mycosphaerella citrullina and their relation to black rot of squash
Authors: Curren Thomas
Published: September 2008

Polygalacturonase (PG), pectin methylesterase (PME), and cellulase (Cx) were obtained from liquid cultures of Mycosphaerella citrullina and were also extracted from infected squash fruit tissue. The pH optima for PG, PME, and Cx were 4, 7, and 5, respectively. Newly rotted squash tissue from the lesion margin was high in PG activity and low in Cx and PME. Older infected tissue was low in PG and PME but had Cx activity almost three times that from the lesion margin.Infected tissue from the center of the lesion had 18–39% as much pectin as healthy tissue and tissue from the lesion margin had 25–63% as much pectin.
Crown gall: effect of temperature on tumorigenesis in pea seedlings
Authors: Kurkdjian A. , Manigault P. , Beardsley R.
Published: September 2008

The development of crown gall tumors on decapitated pea seedlings grown in vitro is evaluated in terms of the mean weight of excised tumors. Reproducible quantitative results are obtained when mean weights of tumors are adjusted for the growth of lateral shoots. The regression line for tumor weight on the length of lateral shoots suggests that the growth of tumors and shoots is competitive. Optimal tumor formation occurs when seedlings are inoculated either immediately or within a few hours after decapitation of the seedlings. Wound healing after decapitation is not accompanied by the appearance of cells in stages of active division. Dividing cells are not observed in tissues below decapitation sites unless seedlings are inoculated with the crown gall bacterium. In darkness, large tumors develop within 2 weeks on inoculated seedlings kept at 24 °C. However, although normal growth continues, tumor formation is almost completely inhibited at 15 °C. When inoculated seedlings are held at 24 °C and 15 °C for alternate periods of varying duration, the adjusted tumor weight decreases as the duration of the period at the lower temperature increases. However, tumor size is not determined simply by the time interval during which plants are exposed to the inhibiting temperature, but also by the order of exposure to the two temperatures.
Activity of gibberellin A24 in 10 plant bioassays
Authors: Pharis R. P. , Crozier A. , Reid D. M. , Kuo C. C.
Published: September 2008

The activity of gibberellin A24 (GA24) has been tested in 10 plant bioassay systems. Relatively high activity was recorded in the cucumber, dwarf rice, and d-2 and d-3 dwarf maize bioassays; d-5 dwarf maize seedlings were only moderately sensitive. In amounts of less than 1 μg, GA24 was inactive in the lettuce hypocotyl, lettuce root, dwarf pea, d-1 dwarf maize, barley half-seed, and cypress flower induction bioassays.
Saprophytic development of the flax rust Melampsora lini, race No. 3
Authors: Turel Franziska L. M.
Published: September 2008

A medium containing 0.1% yeast extract (Difco) in addition to sucrose, inorganic salts, and chelated iron supported saprophytic growth of Melampsora lini (Pers.) Lév., race No. 3. Cultures were started with sterile uredospores from rust-infected flax tissue cultures and were maintained for over 5 months through up to eight transfers. In some aging parts of living mycelial cultures, single one-celled teliospores were formed on aerial hyphae, and in other parts composed of dense masses of firm, small cells, clusters of uredospore-like structures were found. Growth and survival of mycelium were better when 4% sucrose was used instead of glucose, and when 500 mg/l of K2HPO4 was present in addition to the routinely used potassium monophosphate. Spore production was increased by raising the yeast extract concentration to 0.2%.
Normal and abnormal plants from carrot root tissue cultures
Authors: Ibrahim R. K.
Published: September 2008

Callus from carrot root explants was induced to differentiate and grow to carrot plants under the effect of added auxin and kinetin and in the absence of coconut milk. The morphological abnormalities produced with high kinetin concentration are described and discussed.
An introduction to the genetics of the fungus Coniochaeta veluitina
Authors: Cooke F. , Tan H. , Good H. M.
Published: September 2008

The fungus Coniochaeta velutina (Fuckel) Munk., which inhabits defective xylem in maple trees, has been developed for a joint genetical and plant pathological program. This paper describes progress made in the genetical aspect of the problem. From the more than 80 mutants forms which have been isolated after ultraviolet irradiation, 34 have been analyzed genetically by random spore analysis. Many of the mutant strains were incapable of acting as protoperithecial parents in crosses, thus limiting the number of crosses which could be made. Three linkage groups have been discovered, but many of the genes investigated showed no linkage with any other. This finding is in keeping with similar genetic analyses with other fungi.Linkage between the two pyrimidine-requiring mutants in Coniochaeta parallels a similar finding in Neurospora.
Aeciospore release in Gymnosporangium
Authors: Pady S. M. , Kramer C. L. , Clary R.
Published: September 2008

Aeciospore release was studied in Gymnosporangium clavipes Cke. & Pk., G. globosum Farl., and G. juniperi-virginianae Schw. under natural and controlled conditions. In nature diurnal periodicity occurred in all species with spores released in the morning as humidity dropped. Precipitation caused immediate release in G. clavipes and G. globosum but prevented release in G. juniperi-virginianae because of the hygroscopic peridia. Under constant conditions of 70 °F, 90% R.H., photoperiod 12 hours beginning at 8 A.M., spore release in G. clavipes and G. globosum appeared to be continuous. In G. juniperi-virginianae under the same conditions there were twin peaks, a major one between 8 and 10 A.M. and a smaller one at 8–10 P.M. With a dew cycle inserted for 4–12 hours, G. clavipes and G. globosum released spores during the dew period but the hygroscopic peridia of G. juniperi-virginianae closed the opening, preventing aeciospore release. Upon return to 90% R.H., spore release in G. clavipes and G. globosum declined for 3–9 hours, then returned to a steady level but G. juniperi-virginianae released great numbers of spores 2–4 hours after the dew period, because of the action of the peridial strands. In all species, fresh dry spores are shrunken and irregular, expanding immediately in contact with free water, shrinking as water is lost. Spore release is correlated with free moisture in G. clavipes and G. globosum and in all species with rapidly declining humidities.
Seasonal and diurnal expansion and contraction of fruits of forest trees
Authors: Chaney W. R. , Kozlowski T. T.
Published: September 2008

Seasonal and diurnal expansion and contraction of growing fruits of Acer rubrum L., Prunus serotina Ehrb., P. pensylvanica L., P. virginiana L., Quercus rubra L., and Corylus cornuta Marsh, var. cornuta were measured with modified Fritts dendrographs during the summers of 1966 and 1967. Throughout much of the summer the fruits exhibited recurrent shrinkage during the day and expansion at night. Fruit diameter fluctuations in 1967 were related to changes in vapor pressure deficit. Expansion of fruits generally occurred when vapor pressure deficit was decreasing or low and contraction resulted when vapor pressure deficit was increasing or high.
The relative importance of initiation and early development on cone production in Douglas fir
Authors: Owens John N.
Published: September 2008

Lateral bud initiation as determined by increased succinic dehydrogenase activity in the axils of certain leaves occurs by April 1 in the Victoria area. The number of lateral buds initiated did not vary significantly in 1967 and 1968 while the number of buds which developed did. Not all primordia which are initiated develop. Some abort very early and disappear completely while others develop bud scales then cease development and become latent. The rest of the primordia fully develop as vegetative, male, or female buds. In 1967 when abundant cones developed, 56% of the primordia fully developed and most of these became reproductive buds. In 1968 when no cones developed, only 31% of the primordia fully developed and all of these became vegetative. The number of cones produced was, therefore, not determined directly by the number of primordia initiated but by the proportion of primordia which developed as reproductive buds. The presence of abundant maturing cones on shoots formed the previous year greatly reduces the number of primordia which develop and, also, reduces the possibility of these becoming reproductive buds. Previous vegetative growth and cone crops affect the cone productivity in subsequent years and help explain the cyclic pattern of reproduction in Douglas fir.
Some species segregated from the genera Cryptospora, Cryptosporella, and Sillia
Authors: Reid James , Booth Colin
Published: September 2008

Pleocryptospora n. gen. (type, Pleocryptospora bambusae (Speg.) n. comb.), and Vleugelia n. gen. (type, Vleugelia betulina (Bubak & Vleugel) n. comb.) are described as members of the order Sphaeriales. Pseudocryptosporella n. gen. (type, Pseudocryptosporella polylepidis (Müller) n. comb.) is described as a member of the family Diaporthaceae, order Sphaeriales, and Eudothia eugeniae (Nutman & Roberts) n. comb. (≡ Cryptosporella eugeniae Nutman & Roberts) is proposed.
Nitrogenous compounds in the xylem sap of American elms with Dutch elm disease
Authors: Singh Dilbagh , Smalley Eugene B.
Published: September 2008

Thirty-two ninhydrin-positive nitrogenous compounds were present in the xylem sap of 6- to 9-year- old American elms. Twenty-six of these compounds were identified. Total concentration of nitrogenous materials was several times higher in diseased than in healthy sap after inoculation during the susceptible period in the spring, but was lower after inoculations during the late resistant period. Percentage compositions of γ-amino-n-butyric acid, proline, and alanine in diseased sap increased after both spring and mid-summer inoculations. Proline, which was present in trace amounts in healthy sap, constituted 14 to 38% of the total in diseased sap. Percentage concentrations of amide nitrogen in diseased sap were reduced 50% or more in all inoculated trees. Percentages of ammonia, aspartic acid, glutamic acid, and several other amino acids did not change.
Ontogenetical and experimental studies of the floral apex of Portulaca grandiflora. 2. Bisection of the meristem in successive stages
Authors: Soetiarto Siti Raswati , Ball Ernest
Published: September 2008

Floral apices at the stages of sepals, petals, stamens, upright carpels, and elevated carpels were bisected by microscalpels, and the regeneration of the meristem halves, their grafting together, and the production of new appendages were studied. At the sepal stage the two halves regenerated into twin flowers, producing petals, stamens, and carpels above the cut surfaces which grafted together. Cusick's finding that, for a particular organ to be formed alongside a wound, the incision must be made before organs of this kind have appeared in their normal positions, was supported. At the stage of petals, however, the twin flowers produced petals as the first new appendages above the cut surfaces. At the stage of stamens, the first appendages produced above the cut surfaces were carpels, again supporting Cusick. Sometimes the new carpels so formed constituted separate adjacent whorls on the twin flowers. At both stages of carpels, the rest of the floral apex (receptacle) showed no regeneration except rapidly grafting together. The reunited receptacle was then used as in normal ontogeny, in formation of carpel margins on which ovules would later have been borne. Generally, cells beneath wound surfaces showed few divisions, compared with the vigorous responses of bisected shoot apices of other plants. Grafting, which did not occur in the terminal regions of bisected shoot apices, readily occurred at cut surfaces of halved floral apices, and this latter response became progressively more rapid in later stages of floral ontogeny. This grafting, along with progressive loss of potential for production of new lateral appendages, are interpreted as manifestations of aging in this determinate meristem, and support the hypothesis that differentiation is concomitant with loss in capacity for growth.
Genetic control of cone clusters and precocious flowering in Pinus sylvestris
Authors: Teich A. H. , Holst M. J.
Published: September 2008

A Scots pine clone bearing cone clusters transmitted precocity to a portion of its progeny resulting from crosses to clones having normal cone distribution. Inheritance appeared to be governed by a single major gene whose expression was dominant or recessive depending upon which clone it was mated to. Differences of reciprocal crosses indicated maternal or cytoplasmic influence. This genetic variation in precocity can be used to reduce the generation interval, thereby facilitating genetic studies and breeding programs. Seed yield per pollination bag was several times greater for cone clusters than for normally distributed cones although viable seed per cone was 20% less. This can reduce the cost of producing hybrid seed if artificial pollination is required.
Interrelationships of Ledum species and their rust parasites in Western Canada and Alaska
Authors: Savile D. B. O.
Published: September 2008

Ledum glandulosum extends northward from Western United States into southern British Columbia in and east of the Cascade Range and into extreme SE British Columbia and SW Alberta in the Rocky Mts. Further north, within the range of L. groenlandicum but beyond that of L. glandulosum, hybrids between the two species occur, notably in and near Banff National Park, indicating that L. glandulosum formerly extended further north. The hybrids form an irregular swarm among typical L. groenlandicum rather than a cline; for this reason, and because of numerous morphological and other distinctions, the taxa are maintained as species. L. groenlandicum and L. palustre ssp. decumbens overlap in Alaska, Yukon, and Mackenzie in a belt up to 700 miles wide. Six definite hybrids were detected out of ca. 300 specimens from the sympatric zone, and ca. 30 specimens showed signs of probable minor introgression. The marked sympatry with minimal hybridization makes it necessary to maintain L. groenlandicum at specific rank. A rust, Chrysomyxa ledicola, that freely attacks L. palustre ssp. decumbens and L. groenlandicum does not infect L. glandulosum, but it attacks the hybrids in the Banff region except those closely approaching L. glandulosum. Another rust, C. ledi, has developed morphologically distinct varieties each specialized to a single Ledum. In the Banff region hybrids have been found between C. ledi var. glandulosi and C. l. var. groenlandici on L. glandulosum × groenlandicum. C. ledi var. ledi, on L. palustre (including ssp. decumbens) is morphologically distinct from C. ledi var. groenlandici, further emphasizing the sharp distinctness of L. groenlandicum from L. palustre ssp. decumbens.
Palynology of the Eocene Kitsilano Formation, southwest British Columbia
Authors: Hopkins Jr. William S.
Published: September 2008

Approximately 55 genera and 75 species of plant microfossils are illustrated and described from the Kitsilano Formation of southwestern British Columbia. The general composition of the flora suggests a humid, warm temperate climate prevailed at time of deposition. Previous work on plant megafossils indicates a late Eocene to possibly early Oligocene age. Plant microfossils recovered in this study support a probable middle to late Eocene age for the Kitsilano Formation.
Effect of temperature on dry matter production of Douglas-fir seedlings during bud dormancy
Authors: Brix Holger
Published: September 2008

Bud dormancy was induced in Douglas-fir seedlings 90 days after seed germination. Dry matter production of bud-dormant plants was determined for a 7-week growth period at five controlled temperatures from 2 to 24 °C. There was no significant temperature effect between 7 and 24 °C on total dry matter production, which at 2 °C was reduced. Dry weight of the root was affected more by temperature than that of the plant top. A pronounced temperature effect on dry matter production was found previously between 13 and 18 °C for plants in the stage of leaf production. This did not occur for bud-dormant plants because temperature effect on leaf production was not present. Net assimilation rates during bud dormancy were generally lower than during the stage of leaf production, especially at low temperature. This may have been caused by a reduced "sink" for use of photosynthates during bud dormancy.
Pycnidium production by Botryodiplodia theobromae. I. The relation of light to the induction of pycnidia
Authors: Ekundayo J. A. , Haskins R. H.
Published: September 2008

Cultures of Botryodiplodia theobromae Pat. produced pycnidia abundantly on several media under continuous irradiation with fluorescent light. The fungus did not sporulate when grown in darkness. Irradiation of cultures with a light intensity of 15 foot-candles for 4 days was sufficient to stimulate pycnidial production, but for appreciable sporulation to occur over the same exposure period, higher light intensities are required. Irradiation of cultures through glass color filters showed that long-wave ultraviolet radiation stimulated sporulation.
Mitosis and the development of thin-walled sporangia, resistant sporangia, and gametangia of Allomyces
Authors: Flanagan Patrick W.
Published: September 2008

A study was made of nuclear behavior in Allomyces during development and germination of thin-walled sporangia, gametangia, and resistant sporangia. The pattern of nuclear migration, division, and multiplication during development in thin-walled sporangia and gametangia was found to be similar. No evidence could be found to indicate that nuclei in developing resistant sporangia multiply by mitosis. The mitotic divisions of nuclei of Euallomyces and Brachyallomyces isolates are described.
Dormancy regulation: hormonal interaction in maple (Acer platanoides)
Authors: DeMaggio A. E. , Freeberg J. A.
Published: September 2008

Whole buds and excised apices (bud scales removed) from dormant trees of Acer platanoides grow in sterile culture in long days but have different responses to gibberellic acid treatment. Bud growth is stimulated by the hormone in long and short days but apices are unaffected. Abscisic acid inhibits not only gibberellin-stimulated bud growth but also the photoperiodically stimulated growth of apices.
Variation among monosporous progeny of Phytophthora infestans
Authors: Upshall Alan
Published: September 2008

Significant variation for growth rate along artificial medium, on a similar scale to that reported in 1968 by Caten and Jinks, has been uncovered by propagating isolates of Phytophthora infestans by single zoospores or single sporangia. However, there are marked points of difference with the previous work. A similar study of more isolates is required before it can be ascertained whether these differences are related to the pedigree of the parental isolate.
The shoot apex in eastern white pine: its structure, seasonal development, and variation within the crown
Authors: Owston Peyton W.
Published: September 2008

Structure of the shoot apex in eastern white pine (Pinus strobus L.) was similar to that described for other members of the genus. The overwintering bud contained all primordia for the next season's growth, and the apical meristem exhibited ginkgoid cytological zonation. Seasonal development at the shoot apex was divided into three phases: dormancy, extension of overwintering bud accompanied by formation of new cataphylls, and formation of primordia in the axils of some cataphylls. Terminal shoot apices decreased in size and number of primordia with lower position in the crown. Height/diameter ratio of the apical meristem increased with lower crown position, and cytological zonation was absent in apices in the lowest part of the live crown. Such variation within individual trees makes it difficult to describe or compare species on the basis of limited sampling. By late summer or early fall of the present study, dwarf shoot primordia possessed sheath scale and needle primordia. But primordia of flower buds and lateral vegetative buds could not be distinguished from them. Past work with soft pines has shown similar results. Hard pines, on the other hand, have been shown to differentiate flower bud primordia during the season of their formation.
The effect of abrupt temperature increase on growth and phosphorus fractions of Pisum sativum
Authors: Potts J. Rowell M. , Ormrod Douglas P.
Published: September 2008

Pea plants were grown in controlled environments at 25/15 C day/night temperatures and transferred abruptly to each of three higher temperatures, 32/22, 35/25, and 38/28 C, to determine the effects on growth and development and on phosphorus fractions. Samples were taken for analysis on a logarithmic high-temperature exposure time scale. Rate of node formation increased sharply during the first 24 hours of exposure to the elevated temperatures and then declined to a rate which was somewhat greater than that of 25/15 C plants. Rate of internode elongation was initially stimulated and then slowed slightly during continued high temperature exposure. Inorganic phosphorus declined slightly within 10 minutes of temperature increase but increased to about three times the original level by 6 days. Organic, lipid, and nucleic acid and protein phosphorus were not appreciably affected by the temperature change.