bluuebunny/crossref_metadata_2025 huggingface dataset:
Exogenous budding from ascospores of Taphrina
Authors: Muthappa B. N.
Published: September 2008

Taphrina ulmi (Fkl.) Johanson, collected on the leaves of Ulmus alata Michx., was found to produce exogenous blastospores from ascospores within the ascus.
A structural peculiarity observed in the sexual embryo sacs of Dichanthium intermedium
Authors: Saran Sunil , Wet J. M. J. de
Published: September 2008

In an acetocarmine squash study of the ovules of the compilospecies Dichanthium intermedium, an opening was consistently observed on the wall of the eight-nucleate sexual embryo sac directly below the micropyle. Such an opening was never observed in the four-nucleate aposporous sac. It was postulated that the opening could develop because of a difference in the mode of thickening of the wall of the two types of embryo sacs. The opening would provide a path of least resistance to the growing pollen tube and enhance the chances of fertilization, thus favoring sexuality in a facultatively apomictic plant.
Environmental modifications of leaf surface traits in Datura stramonium
Authors: Sharma Gopal K. , Dunn David B.
Published: September 2008

Studies of cuticular modifications of leaves by the environment were conducted on Datura stramonium L. (Blakeslee seed lot, box 8-451) to determine the degree of constancy of cuticular features when plants were subjected to different environmental conditions. This species was considered to be a highly inbred line with a high degree of genetic constancy. The plants were subjected to five environmental conditions, from xeric to very humid. Sinclair and Dunn's method (reported in 1961) of making plastic cuticular imprints was used. It was concluded that the stomatal size classes, mean stomatal size, subsidiary cell complex, pattern of stomatal development, and the type of trichome and trichome distribution pattern were consistent. Stomatal index was generally reliable, except under extreme environments where the plants probably would not have survived in nature, under competition. Stomatal frequency, epidermal cell frequency, and trichome frequency were inconsistent under the different environmental conditions. The total leaf area was so easily modified that absolute stomatal numbers described by Gupta in 1961 were not worth calculating.
Growth of noninfected and Plasmodiophora brassicae infected cabbage callus in culture
Authors: Williams P. H. , Reddy M. N. , Strandberg J. O.
Published: September 2008

Noninfected cabbage callus and Plasmodiophora brassicae infected callus isolated from clubroot galls were maintained for over 40 successive transfers on Murashige-Skoog's medium modified to contain 0.5 mg/l of α-naphthalene acetic acid. Infected callus if transferred at 7- to 12-day intervals grew rapidly, doubling its dry weight about every 3 days, whereas noninfected callus doubled its dry weight about every 5 days. Approximately one-third of the cells in infected callus contained the parasite in various stages of its life cycle, ranging from small vegetative plasmodia to mature resting sporangia. Sporangia isolated from callus were viable and produced clubroot inoculated on cabbage seedlings. When a high percentage of the plasmodia in infected cells in any portion of a callus underwent sporogenesis, the callus growth slowed and the tissues became brown. By transferring only actively proliferating callus a high percentage of plasmodia could be maintained in the vegetative condition. Infected callus resembles closely gall tissue from natural clubroot both cytologically and chemically and thus should be a useful material for studying parasitism and the processes of hypertrophy and hyperplasia in a contaminant-free system.
Karyotypes and morphological variation in the sessile-flowered trilliums of North Carolina
Authors: Serota Cornelia Ann
Published: September 2008

Six populations of apparently morphologically similar sessile-flowered Trillium (known taxonomically as T. cuneatum Raf. and T. luteum (Muhl.) Harb.) observed growing at elevations between 800 and 1700 ft in the Appalachians of western North Carolina and eastern Tennessee exhibit a wide range of variability by observation. The extent of variability was assessed by using statistical and karyotypic methods of analysis and by intraspecific cross-pollination. A correlation exists between the mean coefficient of variability and (1) the size of the population and (2) the degree of geographic isolation. The number of types of each kind of chromosome (A–E), as resolved by cold treatment, varies by one type from population to population. The homozygosity for the six populations is 85.8%, and the distribution of euchromatin is not complex. Intraspecific cross-pollination was effective among 76% of the test crosses. A review of the statistics and other morphological data indicates that the presence or absence of anthocyanins, flower scent, and the degree of geographic isolation are the three major variants among the six populations. These kinds of Trillium grow sympatrically with T. grandiflorum (Michx.) Salisb., T. simile Gleason, T. erectum var. album (Michx.) Pursh, T. flexipes Raf. (T. gleasoni Fern.), and T. erectum L. The cumulative karyotype for the six stands indicates that these plants have not hybridized with any of the above species and varieties. Although these plants have been classified as T. cuneatum Raf. in some stands and as T. luteum (Muhl.) Harb. in others the data demonstrate that these six stands represent one discontinuous population of a sessile-flowered Trillium. Trillium discolor Wray, although relatively rare in western North Carolina, also grows here. Although T. discolor is not directly involved in this problem, its description and distinctive karyotype are included.
The correlation between electrical behavior and cytoplasmic streaming in Chara braunii
Authors: Pickard William F.
Published: September 2008

The correlation of electrical behavior and cytoplasmic streaming in internodal cells of Chara braunii was studied by a voltage clamp technique. The observations were as follows. (i) Neither axial currents nor hyperpolarizing currents are adequate to stop the streaming. (ii) Below the threshold for excitation, streaming was independent of vacuolar voltage. (iii) In cells subjected to step depolarizations, streaming stoppage coincided with the peak of the resultant action current. (iv) Neither an action current nor an action potential seemed to be an essential correlate of streaming stoppage, but a sudden variation in membrane conductance was always associated with stoppage. (v) Recovery of streaming after an electrical excitation was complex and appeared to proceed most rapidly when the cell's conductance was at or near resting level. These data are consistent with the view that the mechanism responsible for streaming is strongly coupled to the plasmalemma and that it is disrupted by the variations in ionic conductance which characterize electrical excitation of the plasmalemma.
Photoperiodism and rhythmic flower induction: complete substitution of inductive darkness by light
Authors: Cumming Bruce G.
Published: September 2008

In a short-day response type of Chenopodium rubrum (ecotype 60°47′ N), light of a relatively low red/far-red ratio—but of sufficient energy to allow photosynthesis—can bring about induction of flowering when it completely replaces a single dark period interrupting continuous white light. When high-intensity white incandescent light was interrupted for less than a 24-hour period, a longer period of inductive light than darkness was required even for minimal induction. An inductive light interruption of at least 60 hours was required for 100% flower induction. The result of such forcing of the system by inductive light, as compared with the circadian rhythmic induction that occurred in darkness, was a change towards a more linear inductive response and there were indications (requiring confirmation) of oscillations of higher frequency.When seedlings were maintained continuously in optimal inductive light or in darkness, after an initial high intensity white light period, there was some flower initiation within 5 days in inductive light, but not until about 10 days in darkness, and then only when sucrose was supplied throughout darkness.There were suboptimal and (inhibitory) supraoptimal effects on induction when the R/FR ratio and (or) the energy of inductive light were decreased or increased, respectively. These results, in conjunction with the effects that were obtained when glucose and 3(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) were applied in inductive light as compared with darkness, implicate both photosynthate and phytochrome-Pfr as having a positive (promotive) effect during normal inductive darkness.These findings emphasize that the important controls in photoperiodism and flowering may be quantitative rather than qualitative in character, because it can now be questioned whether there is any essential dark-requiring reaction in the induction not only of long-day but also of short-day plants.
Stem growth reaction in young red pine to the removal of single branch whorls
Authors: Stiell W. M.
Published: September 2008

Single whorls of branches, located at different levels in the crown, were removed from 13-year-old Pinus resinosa (Ait.) trees. One-year diameter growth of the stem between whorls and below the crown, and of the leader, was used to evaluate treatment effects. Principal inferences drawn were that growth of an internode within the crown is mainly influenced by the whorl immediately above it; growth of the stem just below the crown depends heavily on all whorls; and whorl foliage does not positively influence development of either the current or previous year's leader.
Cytotaxonomy of some Cirsium species of the eastern United States, with a key to eastern species
Authors: Moore R. J. , Frankton C.
Published: September 2008

The morphology and chromosome number of nine species of Cirsium of eastern North America are considered. Chromosome counts are presented for the first time for C. iowense, 2n = 18; C. lecontei, 2n = 32; C. nuttallii, 2n = 24, 28; C. repandum, 2n = 30; C. smallii, 2n = 34; C. engelmannii, 2n = 20; C. texanum, 2n = 22, 24; C. virginianum, 2n = 28. Additional chromosomes, possibly to be considered as accessories, were found in C. nuttallii, C. engelmannii, and C. texanum. These chromosomes render uncertain the number characteristic of these species. A key to the 26 native and introduced species found in Canada and the United States east of 100° west latitude is presented. The interrelationships of the eastern species and of the species of the western series Undulata are discussed.
Annual variation in strains of barley yellow dwarf virus in Manitoba, and the occurrence of greenbug-specific isolates
Authors: Gill C. C.
Published: September 2008

Seventeen isolates of the aphid-borne barley yellow dwarf virus (BYDV), collected in southern Manitoba in 1966, were transmitted from oats to oats most efficiently by Rhopalosiphum padi. They were transmitted also by Macrosiphum avenae and all but two were transmitted by Schizaphis graminum and Acyrthosiphon dirhodum. Most of these isolates were not transmitted by R. maidis.Only 3 of 25 isolates collected in 1967 were transmitted by the five species of aphids in a pattern similar to that of the isolates collected in 1966. Twenty of the remainder were transmitted with a moderate to high degree of specificity by R. maidis, R. padi, or S. graminum. Two of the latter isolates were transmitted only by S. graminum. When the transmissibility of one of the isolates, for which S. graminum was the most efficient vector, was examined more critically, both the relative and the specific efficiency of the three vectors varied with the age of the infection in the source plants, though S. graminum was always the most efficient vector.
Development and release of conidia of Phyllactinia corylea
Authors: Clerk G. C. , Ankora J. K.
Published: September 2008

The conidiophores of Phyllactinia corylea stand erect from the ectophytic hyphae and abstrict conidia in basipetal succession from a terminal generative cell. Only a single conidium, however, is usually found on the conidiophore at any time. As soon as each conidium is mature, the generative cell bends through more than 90° while the conidium at the same time becomes almost separated from it by a circum-scissile shearing of the limiting septum. The conidium in that condition is readily detached by wind. Conidial chains are formed in still air. Mature conidia still attached to the conidiophore never germinate but immature ones may do so.
In vitro growth of gelatin suspensions of uredospores of Puccinia graminis f. sp. tritici
Authors: Coffey M. D. , Bose A. , Shaw Michael
Published: September 2008

A comparison was made of the growth of the Australian isolate of Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn. race ANZ 126-6,7 on 1.5% Difco Bacto-Agar using water and 15% gelatin as suspension media for seeding uredospores on the media. A range of media was tested, the basic constituents being 3% glucose, Czapek's minerals, peptone, and 1% bovine serum albumin. Spores embedded in gelatin gave much better growth than those applied to the agar surface in water suspension in all media. Sodium citrate (0.2%) inhibited growth; pectin (0.2%) did also, but partial recovery occurred later. Best growth was on the basic medium seeded with uredospores in gelatin. The mycelium was white and fluffy in appearance at first, but collapsed later as a dense brown stroma developed beneath it. Diffusion of brown pigment into the agar medium took place with the gelatin, but not the water series. Sporulation was observed after 60 days in a few colonies and was located in the brown stroma. Spores were non-pigmented, oval in shape, and similar in size to typical uredospores. It is suggested that the physical environment around the spores affects growth.
Benzoic and salicylic acids isolated from a glycoside of aspen bark and their effect on Hypoxylon pruinatum
Authors: Hubbes Martin
Published: September 2008

Benzoic and salicylic acids, isolated from an unknown glycoside of aspen bark, were identified as the main fungistatic factors of this compound against Hypoxylon pruinatum (Klotzsche) Cke. The identity of the carboxylic acids was established by thin-layer chromatography and ultraviolet and infrared spectrophotometry.On a malt agar medium, benzoic acid inhibited the growth of the fungus at 1 × 10−3 M, whereas salicylic acid at the same concentration stimulated growth. Complete inhibition of growth of the fungus was obtained with benzoic acid at a concentration of 4 × 10−3 M and with salicylic acid at 5 × 10−3 M. Total inhibition was also obtained when both benzoic and salicylic acids, each at a concentration of 2 × 10−3 M, were simultaneously present in the malt agar medium.On a synthetic medium, benzoic acid and glucose, each at a concentration of 1 × 10−3 M, inhibited the growth of the fungus. At this concentration salicylic acid had no effect.When ammonium nitrate was replaced simultaneously by asparagine, alanine, and glutamine, benzoic acid at 2 × 10−3 M, and glucose at 3 × 10−3 M promoted the growth of the fungus. The same growth was also obtained when benzoic acid at 1 × 10−3 M and glucose at 1 × 10−3 M were both added to the medium.
Factors in elm wood responsible for the production of coremia by Ceratocystis ulmi
Authors: Hubbes Martin , Pomerleau René
Published: September 2008

The production of coremia (synnema) by Ceratocystis ulmi (Buis.) C. Moreau on elm wood extracts is governed by certain yet unidentified compounds under the influence of light.
Notes on the genus Encoeliopsis
Authors: Groves J. Walton
Published: September 2008

Five new combinations are proposed in the genus Encoeliopsis, E. bresadolae (Rehm), E. ericae (Fr.), E. laricina (Ettl.), E. ledi (Alb. & Schw. ex Fr.), and E. oricostata (Cash), together with a detailed discussion of the nomenclatural problems involving the type species, E. rhododendri (Ces. ex DeNot.) Nannf.
Erratum: Alterations of the host wall surrounding the infection peg of powdery mildew fungi
Authors: McKeen W. E. , Smith R. , Bhattacharya P. K.
Published: September 2008

not available
Nomenclatural changes for Taxodioxylon antiquum Ramanujam & Stewart and T. antiquum Prakash
Authors: Ramanujam C. G. K. , Stewart Wilson N.
Published: September 2008

Taxodioxylon antiquum Ramanujam & Stewart (1969) is renamed as T. multiseriatum nom. nov. Taxodioxylon antiquum Prakash (1968) is considered to be a later synonym of T. gypsaceum (Göppert) Kräusel (1949).
Behavior in vitro of plant cells from various sources within the same organism
Authors: Barker W. G.
Published: September 2008

Explants derived from widely divergent tissues within the body of the basswood, Tilia americana L. (ovary wall, root and shoot cambia, perimedullary region, petiole), have the same general appearance when growing as a callus culture on identical media. The cambial-derived calli will meld into a single unit when placed in contact in the same culture bottle. Similarly, calli from several sources of wheat, Triticum aestivum L., are indistinguishable in vitro.From the standpoint of purely observational criteria, parenchyma explanted from several organs within the same organism responds in a seemingly identical way to the cultural environment.
Absolute pollen frequencies and carbon-14 age of a section of Holocene Lake sediment from the Riding Mountain area of Manitoba
Authors: Ritchie J. C.
Published: September 2008

A section of Holocene lake sediment in the Southern Boreal Forest of Manitoba was re-sampled, and the sedimentation rate (0.039 cm per annum) calculated from eight carbon-14 age determinations. Pollen accumulation rates were computed, and an absolute pollen frequency diagram constructed. It suggests modifications of an earlier reconstruction of vegetation, based on relative pollen frequencies. A spruce-dominated assemblage occurred from about 11 500 to 10 000 B.P., when there was a change to a treeless vegetation of a grassland type. This persisted until about 2500 B.P., with the possible interpolation of an aspen parkland phase from 6500 to 2500 B.P. The boreal forest in its present form (dominated by spruce, birch, and aspen, with local occurrences of pine, fir, larch, and oak) returned at 2500 B.P., presumably in response to a deterioration in climate (cooler and (or) wetter).
Taxonomic significance of protein patterns of rust species and formae speciales obtained by disc electrophoresis
Authors: Shipton W. A. , Fleischmann G.
Published: September 2008

Soluble uredospore proteins were isolated from physiologic races or isolates of Puccinia graminis f. sp. avenae, P. graminis f. sp. secalis, P. graminis f. sp. tritici, P. recondita f. sp. secalis, P. recondita f. sp. tritici, P. coronata f. sp. avenae, and P. hordei. The protein extracts were subjected to polyacrylamide gel (disc) electrophoresis and the resulting patterns were compared.Patterns were assessed by two methods based on Ef values and by a third method based on subjective assessment of color intensity of stained proteins. Assessments based on Ef values differed for each method and were in almost total disagreement with conclusions derived by the third method.No useful inter-subspecific and interspecific comparisons were possible using Ef-based data because the host on which the rust was grown influenced the patterns. Evidence obtained by the third method of assessment contradicted this conclusion, for the host only appeared to influence color intensity and width of individual bands. Thus, using the color intensity method it was found that the differences between species were greater than between formae speciales, and the latter, with one exception, differed more than physiologic races. Differentiation between most physiologic races or isolates was impossible.The taxonomic significance of the protein patterns is discussed.
Observations on Wallrothiella arceuthobii, a fungus parasite of dwarf mistletoes
Authors: Kuijt Job
Published: September 2008

Certain aspects of the life cycle of Wallrothiella arceuthobii are detailed from field and microscopical observations. Infected fruits of the host often continue to develop for several weeks after spore dissemination. Sectioned material shows that the fungus tends to avoid the young embryo and endosperm, yet attacks other adjacent mistletoe tissues. Perithecial shape varies considerably between eastern and western North America. Some western specimens show periostiolar locules of unknown function. The genus may be related to Coryneliaceae.
Analytical studies on the shoot apex of Helianthus annuus
Authors: Steeves T. A. , Hicks M. Anne , Naylor J. M. , Rennie Patricia
Published: September 2008

The vegetative shoot apex of Helianthus annuus contains a central zone in which the cell nuclei are relatively large and stain faintly in the Feulgen reaction. Excised apices in the vegetative state were supplied with thymidine-H3 through their sterile, liquid culture medium. Autoradiography after 24 or 48 hours of feeding revealed no significant incorporation of the labeled precursor into central zone nuclei, but extensive incorporation in peripheral regions of the apex. It is concluded that during vegetative growth deoxyribonucleic acid (DNA) synthesis and mitosis are arrested in the central zone or reduced to an extremely slow rate. Microspectrophotometry, however, indicates that the central zone nuclei are not held at the 2C level. With the onset of flowering, cytological zonation disappears in the apex and the incorporation of thymidine-H3 is uniformly heavy throughout the apical region.
Studies on asexual variation in the virulence of oat crown rust, Puccinia coronata f. sp. avenae, and wheat leaf rust, Puccinia recondita
Authors: Bartos P. , Fleischmann G. , Samborski D. J. , Shipton W. A.
Published: September 2008

This study was conducted to determine the nature and extent of variation in cereal leaf rusts. Two different races of oat crown rust, Puccinia coronata f. sp. avenae, were recovered from a mixture of single-spored cultures of races 228 and 393. A further subculturing yielded nine non-parental virulence combinations, which could have resulted from somatic recombination.Single-spore isolates of race 228, avirulent on the oat variety Saia were increased, and screened on Saia. Eighty-seven susceptible infections were obtained from a total of nearly 40 000 infections. This variation could result from a high mutation rate.A unique form of variation was observed when Saia-virulent isolates of race 229 were subcultured. Approximately half the subcultures were virulent and half were avirulent on Saia. Further isolations from the avirulent subcultures were all avirulent. Serial propagation of race 229 continued to give cultures virulent and avirulent on Saia. A stable culture of race 229 virulent on Saia was not obtained. Cytological examination of this race 229 culture showed that most of the spores were dikaryotic. Aneuploidy or cytoplasmic inheritance might account for this variability on Saia.Uredial isolates of wheat leaf rust, Puccinia recondita, differing in virulence and color were also studied for the possible occurrence of recombinants. No recombinants were found in six mixtures, each consisting of two different uredial isolates.
Studies on Cenococcum graniforme. I. An efficient method for isolation from sclerotia
Authors: Trappe James M.
Published: September 2008

The mycorrhizal fungus Cenococcum graniforme can be readily isolated from sclerotia that have been brushed clean and immersed in 30% H2O2 for 10 to 40 minutes. Sclerotia are obtained from small soil samples wetted to a slurry that is swirled to remove the lightweight, sclerotia-containing fraction in a gold-panning type of process. Viable sclerotia sink in water whereas nonviable ones float, so the latter are easily eliminated. Sclerotia have been observed to form in agar cultures, especially those that have been allowed to desiccate slowly for 2 to 3 months.
Vegetative and reproductive development of shoot apices of Pharbitis nil as influenced by photoperiodism
Authors: Bhar D. S. , Radforth N. W.
Published: September 2008

In shoot apices of Pharbitis nil, cytohistological zonation is not clearly delineated at germination. With increase in age, zonation develops and the granular appearance of the cytoplasm disappears. After induction by a single 16-hour dark period the first recognizable sign of floral transition becomes evident on the second day, with increase in the mitotic activity of the apex. On the third and fourth days, the sepals are initiated and the petals and stamens are initiated simultaneously on the fifth day. On the sixth day the carpel primordia originate. Between the 11th and 12th days after the inductive dark period, the pollen grains develop and the style extends. Between the 19th and 20th days the epidermal cells of the stigma become secretory.
Seasonal and diurnal changes in water balance of fruits, cones, and leaves of forest trees
Authors: Chaney W. R. , Kozlowski T. T.
Published: September 2008

Seasonal variations in actual moisture content (MC), moisture content as percent of dry weight (% MC), and dry weight were determined for fruits of Acer rubrum L., Quercus rubra L., and Prunus serotina Ehrb. at weekly or 2-weekly intervals. On selected dates diurnal variations in MC, % MC, and dry weight of fruits or cones and leaves of Quercus rubra, Prunus serotina, P. virginiana L., and Pinus banksiana Lamb. were determined at 4-hour intervals during the day and night. Percentage moisture content of reproductive tissues and leaves was variously influenced by water uptake or loss, change in dry weight, or both of these. The water balance of different tissues of the same organ varied differently, both seasonally and diurnally, in the same species as well as between species. Percentage moisture content alone is not an accurate indicator of internal water balance of plants and should be interpreted in relation to both water weight and dry weight changes of tissues.
Metabolism of aromatic compounds in healthy and rust-infected primary leaves of wheat. III. Studies on the metabolism of tryptophan
Authors: Kim W. K. , Rohringer R.
Published: September 2008

Extracts from healthy and rust-infected wheat leaves were assayed with Lactobacillus plantarum for their tryptophan content. Healthy leaves contained about 20 μg tryptophan per gram fresh weight immediately after detachment, and 2 to 3 times this amount 22 h after detachment.Infection with rust had no effect on the tryptophan content of leaves 3 days after inoculation. Six days after inoculation, the tryptophan content of rusted leaves had increased to about 160% of control levels in resistant leaves, and to 450% of control levels in susceptible leaves.Healthy and rust-infected leaves were allowed to metabolize D,L-tryptophan(benzene ring-U-14C), D-tryptophan(methylene-14C), and L-tryptophan(methylene-14C). Acidic ether extractives were isolated from these tissues and assayed for radioactivity. In all cases, susceptible reacting tissues incorporated more activity into this fraction than either resistant reacting leaves or healthy leaves.Both D- and L-enantiomers of radioactive tryptophan gave rise to activity in indoleacetic acid (IAA), indolepyruvic acid, and indolecarboxylic acid. Malonyltryptophan was labelled only when the radioactive D-enantiomer of tryptophan was present in the feeding solution. Evidence was obtained indicating that D-tryptophan is not normally present in wheat leaves.Infection with rust increased the incorporation of activity from D- and from L-tryptophan(methylene-14C) into IAA, indolepyruvate, and indolecarboxylic acid in susceptible leaves, but not in resistant leaves. After consideration of the effect of isotope competition in the tryptophan pools, these results indicate that infection with rust resulted in increased rates of IAA synthesis, especially in susceptible leaves.
Turpentine composition of Pinus contorta × Pinus banksiana hybrids and hybrid derivatives
Authors: Zavarin Eugene , Critchfield William B. , Snajberk Karel
Published: September 2008

Inheritance of turpentine composition in Pinus contorta × pinus banksiana hybrids has been studied on the basis of 7 pure Pinus banksiana trees, 17 pure Pinus contorta trees, 18 backcrosses to P. banksiana, 32 F1, 6 F2, 41 F3, and 9 natural hybrids. Although it was impossible from the data obtained to formulate an appropriate inheritance model, the results suggested that the differences in turpentine composition are controlled primarily by a limited number of genes with major effects. The major difficulty in working out the inheritance model was the failure to recover, in the F2 and F3 generations, the original levels of β-phellandrene, the quantitatively most important terpene of P. contorta. It is suggested that this might be due to the introduction of competing enzymatic systems, which, by producing independently large amounts of pinenes, would lower the β-phellandrene level.
Carbon dioxide, the substrate for phosphoenolpyruvate carboxylase from leaves of maize
Authors: Waygood E. R. , Mache Regis , Tan C. K.
Published: September 2008

Using a spectrophotometric technique it has been shown that CO2 is the substrate for phosphoenolpyruvate carboxylase (EC 4.1.1.31) from leaves of Zea mays. The Km (CO2) is approximately 7.5 × 10−6 M, which is the order of the half saturation value for CO2 in natural photosynthesis. Studies indicate also that carbonic anhydrase is localized in chloroplasts, isolated by the 'laceration technique' from leaves of Spinacea oleracea, but is absent from leaves of Zea mays. It is speculated that carbonic anhydrase catalyses a 'trap' for the CO2 escaping into the environment via photorespiration.
Effects of deuterium replacement on seed development: influence on excised embryos
Authors: Crane F. A. , Blake M. I. , Uphaus R. A. , Katz J. J.
Published: September 2008

The effects of heavy water on the elongation of excised embryos of several seed species are noted. Under autotrophic conditions, increase in embryo size is small. Added sucrose ameliorates the repressive effects of deuterium on growth. This study shows that the species-specific effects of deuterium are separable from the environmental effects.
Marine fungi of Hawaii including the new genus Helicascus
Authors: Kohlmeyer Jan
Published: September 2008

Among 27 species of marine fungi recovered from natural substrata by the direct collecting procedure, found on the Hawaiian Islands Hawaii, Kauai, Maui, and Oahu (19 Ascomycetes and 8 Deuteromycetes), 22 were new locality and 12 were new Pacific Ocean records. Eight species and Helicascus kanaloanus Kohlm. gen. et sp. nov. (Pleosporaceae?) and Robillarda rhizophorae Kohlm. sp. nov. (Sphaeropsidaceae) occurred on roots of Rhizophora mangle L. Substrates not considered before in marine mycology were submerged branches and roots of Hibiscus tiliaceus L. (seven fungal species) and Pluchea × fosbergii Cooper-rider et Galang (four species). Algae contained three fungi, and foam collections four arenicolous species. Hyphomycetes known from freshwater foam in Hawaii were not found in foam along the seashore. Collections of driftwood and pilings contained 14 species. The origin of the Hawaiian marine fungal flora is discussed. Host-specific Keissleriella blepharospora and Cytospora sp. appear to have been introduced from Florida to Hawaii with seedlings of Rhizophora in 1902. Conidia of R. rhizophorae were able to germinate after freezing at −20 C for 6 months and after repeated thawing and refreezing. Half of the species collected were isolated and growth in pure culture is described. Periconia prolifica Anast. was determined as the imperfect state of Remispora cucullata Kohlm. by use of single ascospore isolations.
A reappraisal of thermodynamic transport coefficients in Nitella cell walls
Authors: Tyree M. T. , Spanner D. C.
Published: September 2008

A reanalysis of the published thermodynamic transport coefficients has led to the conclusion that the contribution of Nitella cell walls to the electroosmotic efficiency of the wall – membrane complex in living Nitella cells has been incorrectly estimated. When the e-o efficiency observed in the living Nitella cell is less than 100 moles Faraday−1 the observed value is an overestimate if attributed to the membrane alone; when the e-o efficiency observed is over 100 moles Faraday−1 the value is an underestimate of the e-o in the membrane. A more detailed analysis of the salt concentration dependence of LPE (the electrokinetic coefficient) and of LPE2/LEELPP (the relative thermodynamic efficiency of electroosmosis) is given. It is found that LPE2/LEELPP reaches a peak efficiency (about 0.6) at about the saline concentration of pond water and xylem sap. It is concluded that the suggestion of Briggs that the electroosmosis observed in living Nitella cells may be a property of the cell wall alone is unlikely to be true.
Ion exchange resin beads as a carrier for growth substances
Authors: Gee H. , Greyson R. I.
Published: September 2008

Dowex-1 ion exchange resin beads bind indoleacetate, naphthaleneacetate, and indoleproprionate ions and release them to plant tissue. We suggest this tool shows considerable potential in assessing the role of growth substances in morphogenesis. Some properties of IAA loaded beads are described.
A shoot-blight disease of western larch in British Columbia
Authors: Funk A.
Published: September 2008

Encoeliopsis laricina (Ettlinger) Groves is shown to be the chief fungus associated with a shoot-blight disease of western larch (Larix occidentalis Nutt.) in the Kootenay region of British Columbia, Canada. Symptoms are described and biological characteristics of the fungus are given.
A note on the quantitative determination of carbohydrate in exudate from single cotton seeds and its significance
Authors: Hayman D. S.
Published: September 2008

A method is described for studying carbohydrate exudation from single seeds. The advantages are that the apparatus for collecting exudates is simple, repeated samples may be obtained without removing or damaging the seeds, and exudation from viable seeds can be determined without including nonviable ones. Different seed lots can be compared on a viable seed basis, and in problems on damping-off diseases, this makes any correlations with susceptibility to preemergence fungal infection more valid. Various factors affecting seed exudation can be readily investigated.
The effect of different water depths on the growth of wild rice
Authors: Thomas A. G. , Stewart J. M.
Published: September 2008

The effect of different water depths on wild rice plants (Zizania aquatica L.) was assessed in terms of morphological and dry weight changes which occurred during a complete life cycle. Specifically, plant heights, number and area of leaves, dry weights of leaf, stem, root, and flower were determined for plants grown under controlled environmental conditions and those under field conditions at Long Point, Lake Erie.Three distinct phases in plant height increase, and associated morphological changes characterized the life cycle of wild rice. While the duration of phases one and three was unaffected by water depth, the time spent in phase two increased with depth and resulted in plants flowering later than those at shallower depths. Sufficient water is required to cover the submersed leaves and to support the floating leaves, while plants at the aerial stage survived with no free water above the rooting media. Yield in terms of dry weight of plant parts is decreased by water depths less than 8 cm and greater than 110 cm. The decline of wild rice in many areas of Ontario is attributed to either excessively low or high water levels during the critical submersed and floating leaf stages.
The genus Rhabdocline Syd.
Authors: Parker A. K. , Reid James
Published: September 2008

The various entities included under the name Rhabdocline pseudotsugae Syd., the fungus causing a needle cast of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), have been placed into two species primarily on the basis of differences in structure of their ascus apices. The ascospores of Rhabdocline pseudotsugae (which includes R. pseudotsugae subsp. pseudotsugae and R. pseudotsugae subsp. epiphylla subsp. nov.) are ejected through variously ruptured thin-walled ascus apices, while ascospores of Rhabdocline weirii sp. nov. (which includes R. weirii subsp. weirii, R. weirii subsp. oblonga subsp. nov., and R. weirii subsp. obovata subsp. nov.) are ejected through distinct annular pores. An emendment to the diagnosis of Rhabdocline has been made. R. weirii subsp. weirii was the only entity found to be associated with the imperfect fungus Rhabdogloeum pseudotsugae Syd. The relationship of Rhabdocline to other members of the Hemiphacidiaceae, the significance of the constancy of the fungus and disease symptoms in Europe, the iodine reaction of asci, and spore maturity are discussed.
Seasonal changes in the macro- and micro-nutrient composition of ovulate strobili and seeds of Pinus resinosa
Authors: Dickmann D. I. , Kozlowski T. T.
Published: September 2008

Seasonal changes in N, P, K, Ca, Mg, Fe, B, Cu, Zn, Mn, Na, and Al of first- and second-year ovulate strobili and developing seeds of Pinus resinosa Ait. were investigated. During the first year, the major macronutrients moved steadily into developing strobili. Nitrogen and P accumulated in high amounts and Ca and Mg in low amounts. Micronutrients also moved into strobili throughout the first year as did Na and Al.The seasonal pattern of uptake and accumulation of nutrients during the second year of strobilus development differed from the first-year pattern. During the period of rapid growth of strobili following fertilization, macro- and micro-nutrients continued to move into cone tissue. However, movement of Mn into strobili stopped abruptly during mid-June when strobili reached maximum size. Beginning in mid-July, N, P, and K began moving out of maturing strobili. Other macro- and micro-nutrients continued to accumulate in strobili during the entire second year.At the same time that mature strobili were beginning to senesce, N, P, K, Mg, Mn, Zn, and Fe rapidly moved into developing seeds. Nitrogen particularly accumulated in high concentrations. Senescing cone tissue appeared to supply much of the N, P, and K that was translocated into seeds. Calcium was present in very low concentrations in seeds whereas Na accumulated in high amounts. Aluminum did not move into seeds after fertilization occurred.
Factors influencing the stratification process in seeds of Acer saccharum
Authors: Webb D. P. , Dumbroff E. B.
Published: September 2008

Several factors affecting the stratification process in seeds of A. saccharum were investigated. Rates of imbibition and quantitative measurements of flow rate made with an osmometer indicate that the testa offers a severe restriction to water flow and that a significant portion of the stratification period is required for adequate water uptake. Respiration rates showed a close correlation with water uptake by the embryos throughout the stratification period. Whole seed needed 40–60 days to break dormancy; however, removal of the pericarps and tearing of the testas reduced the time needed by as much as two-thirds. Presoaking whole seed at 5 °C had a similar effect. Seeds with their pericarps removed and testas pricked and treated with gibberellic acid or kinetin provided the highest percentage germination and germinated in the shortest time. Additional tests showed that oxygen was not a limiting factor, and an inhibitor present in the pericarp evidently does not play a significant role in the dormancy mechanism. The restricted movement of water through the testa apparently controls and complements the metabolic block in the embryo and accounts for the prolonged stratification requirement.
A chemosystematic analysis of some hybrid spruce (Picea) populations in Montana
Authors: Habeck James R. , Weaver T. W.
Published: September 2008

Much of the spruce occurring in western Montana is suspected of being hybrid derivatives from the introgression between Picea glauca and P. engelmannii whose botanical ranges overlap in Montana. These Montana populations were analyzed by chemosystematic methods; resins were collected from typical P. glauca (Manitoba) and typical P. engelmannii (Wyoming) populations and these were analyzed by vapor-phase chromatography, as were resins from western Montana populations. Monoterpene compositions were determined and through the calculation of ratios based on the percentages of limonene, myrcene, and beta phellandrene, a two-dimensional ordination was constructed of the typical and hybrid spruce populations. The methods provide a highly useful approach towards interpreting chemosystematic data collected from Picea populations in the northern Rocky Mountains.
Upper Cretaceous proteaceous pollen from the Edmonton Formation, Alberta (Canada) and their paleoecologic significance
Authors: Srivastava Satish K.
Published: September 2008

The morphological distinctions between the form genera Beaupreaidites and Proteacidites are discussed. Also the genus Beaupreaidites is suitably emended to accommodate proteaceous colpoid pollen with coarse reticulate, retipilate, or verrucose sexine. Three species belonging to Beaupreaidites and three species belonging to Proteacidites are reported from the Edmonton Formation. Two new species are described: Beaupreaidites libitus and Proteacidites auratus. The distribution of proteaceous pollen in Upper Cretaceous strata and their paleoecological significance in the Edmonton Formation are discussed.
Nuclei in haustoria of Phytophthora infestans
Authors: Sivak Bela , Shaw Michael
Published: September 2008

Haustoria of Phytophthora infestans (Mont.) DeBary were stained for ribonucleic acid (RNA) using azure B dye at pH 4.0 after the enzymatic removal of deoxyribonucleic acid (DNA). Nuclei were shown to be present in haustoria from 12 to 35 h after inoculation.
Regulation of starch and sugar levels in tobacco leaves by gibberellic acid
Authors: Lee T. T. , Rosa N.
Published: September 2008

Gibberellic acid (GA3) significantly reduced the level of starch in green leaves of tobacco plants. The total α-amylase activity and the specific activities of α-amylase and invertase were increased by GA3 treatment. Hydrolysis of starch during flue-curing contributed greatly to the increased level of reducing sugars in cured leaf tissue; decreasing the level of starch in green leaves by GA3 effectively lowered the level of reducing sugars after curing.
Effect of hot-water-soluble Thuja plicata heartwood extractives on the growth of Thuja and non-Thuja isolates of Poria weirii
Authors: Morrison D. J.
Published: September 2008

Isolates of Poria weirii Murr. cultured from various hosts may be divided into two groups on the basis of their ability to parasitize Thuja plicata Donn. Measurement of linear growth along wood microsections confirmed that substances inhibitory to one isolate group are hot-water-soluble T. plicata heartwood extractives. Isolates from T. plicata (Thuja) were more tolerant than isolates from Pseudotsuga menziesii (Mirb.) Franco (non-Thuja) to a hot-water extract of Thuja plicata heartwood and its steam-volatile and non-volatile fractions; steam-volatile components caused greatest response differences. With sufficient inoculum potential, non-Thuja isolates may overcome effects of inhibitory compounds in T. plicata heart-wood; however, the resulting infections of T. plicata roots were usually localized. Non-Thuja isolates failed to increase tolerance to steam-volatiles both in laboratory tests and under field conditions. The results have significance for control of Poria weirii.
Life history and iodine nutrition of the marine brown alga, Petalonia fascia (O. F. Müll.) Kuntze
Authors: Hsiao Stephen I. C.
Published: September 2008

The morphological life history of the marine brown alga, Petalonia fascia (O. F. Müll.) Kuntze, has been investigated in unialgal culture, using defined culture media with different iodide concentrations. The zoospores produced from the plurilocular sporangia of P. fascia blades developed directly into protonemata, plethysmothalli, or Ralfsia-like thalli, depending upon the iodide concentration. Protonemata and plethysmothalli survived in iodide-free media. For development of Ralfsia-like thalli and blades the minimal iodide concentrations required were 50.76 × 102 μg/1 and 50.76 × 101 μg/1, respectively. Iodine appears to be an essential element for growth, morphogenesis, and reproduction of P. fascia.
Development of excised potato buds in nutrient culture
Authors: Mellor Frances C. , Stace-Smith Richard
Published: September 2008

Factors affecting the development of excised potato buds into rooted plants were investigated during a program to eradicate latent viruses from commercial potato varieties. Buds 0.4 to 0.8 mm long were excised from heat-treated plants and placed on media modified from that of Murashige and Skoog. Factors that influenced survival and rooting were the composition and pH of the culture medium, the season of the year, the variety of potato, and transfer of buds to fresh media during culture. Liquid medium was superior to solid, both for rate of growth and proportion of rooted buds. Common growth-promoting substances incorporated into the medium were more detrimental than beneficial. Development was optimal at pH 5.7 but rooting was inhibited at pH 4.8 or pH 6.2. Buds excised in the spring and early summer rooted more readily than those taken later in the year. Buds of most varieties rooted satisfactorily but we failed to develop a medium that would guarantee a large proportion of rooted plantlets from excised buds of any variety at any time of the year. Even with the best medium tested, usually less than half of the excised buds developed into established plantlets without transfer to fresh medium. Plantlets that developed shoots without roots were sometimes established by transferring them to soil.
Differential sensitivities to gamma radiation of Phylloxera gall and normal grape stem cells in tissue culture
Authors: Arya H. C. , Hildebrandt A. C.
Published: September 2008

The differential responses were observed of cells from tissue cultures of normal grape stem (GS6-24) and Phylloxera vastatrix Planch leaf gall (GP4-21) exposed to gamma radiation of 100 to 500 000 R from cobalt-60. The percentage survival of cells decreased with increased intensity of radiation. The mitochondria, spherosomes, and nucleus were visibly affected by radiation. The percentage survival of gall cells was lower than that of normal cells after exposure to the same radiation intensity. The irradiated cells did not recover regeneration even when exposed to the smallest dose of 100 R, though a certain percentage of cells survived during 28 days of observation. The effectiveness of 2-mercaptoethylamine hydrochloride (MEA), and 2-aminoethylisothiouronium bromide hydrobromide (AET) at 1 × 10−2–1 × 10−8 M in protecting the cells against gamma radiation was tested by incorporating them in liquid medium containing actively growing cells of normal and gall types. Observation of cells in microcultures exposed to 1000 R showed that MEA at 1 × 10−4 M and AET at 1 × 10−3 M decreased the lethality of radiation to normal grape cells considerably more than to the gall cells. The normal cells treated with 1 × 10−3 M AET and exposed to 1000-R radiation also divided.
The ecological status of Coniochaeta velutina in sugar maple wounds
Authors: Basham J. T. , Good H. M. , Taylor L. D.
Published: September 2008

The development of genetically marked strains of wood-inhabiting fungi would heighten chances of obtaining meaningful results from experiments involving the introduction of such fungi alone or in various combinations at different times into living trees and subsequently evaluating their spread, activity, and interaction with other fungi. Coniochaeta velutina (Fckl.) Munk, a fungus frequently isolated from defective wood associated with trunk wounds of sugar maple, appears to have at least four advantages for this type of research: (1) it frequently infects wounds already colonized by other fungi; (2) it was encountered in a wide range of stages of decay, indicating that it could be successfully introduced into existing colonized wounds; (3) it has been found to be susceptible to genetic analysis; and (4) several clearly marked genetic strains of the fungus are already available.