bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of callus cultures of Prunus persica, P. tomentosa, and P. besseyi to cyanide
Authors: Heuser Charles W.
Published: September 2008

Callus cultures were obtained for cyanide toxicity studies from Prunus persica L. (peach) and two grafting understocks, P. tomentosa Thunb. (Nanking cherry) and P. besseyi Bailey (sand cherry), which are used to dwarf peach. P. tomentosa and P. besseyi callus cultures were faster growing and more friable than P. persica callus. The callus derived from P. persica was more tolerant of high cyanide concentrations, whereas callus cultures from the two understocks were more sensitive to cyanide. The results suggest a detoxication system may exist in peach.
Permeability changes induced by Helminthosporium maydis, race T, toxin
Authors: Gracen V. E. , Grogan C. O. , Forster M. J.
Published: September 2008

We have demonstrated that Helminthosporium maydis, race T, toxic culture filtrates induce electrolyte leakage from treated susceptible corn (Zea mays L.) leaf cells. In a comparison of several cytoplasmic versions of the inbred W182BN, those versions susceptible to the fungus and its toxin in the field demonstrated induced electrolyte leakage while versions rated resistant in the field did not. The total amount of electrolyte leakage of leaves from susceptible Texas cytoplasmic male sterile plants increased with increasing toxin concentrations. Leaves from non-male sterile and resistant cytoplasmic male sterile plants, although much more resistant than T cytoplasm leaves, were not immune to the toxin. If the toxic filtrate concentration or the treatment duration were greatly increased, leaves of the resistant plants exhibited some electrolyte leakage. The electrolyte leakage suggests damage to cellular membranes. This damage may be the result of mitochondrial inactivation induced by the toxin, or it may result from the effect of the toxin on other cellular sites.
Computer graphics in fungal identification
Authors: Kendrick Bryce
Published: September 2008

A flexible, sequential, computer graphics image-retrieval procedure is used in constructing a simple but unorthodox key to didymosporous Hyphomycetes.
The biosystematics, chemotaxonomy, and ecology of Claytonia lanceolata in western Washington
Authors: Douglas George W. , Taylor Ronald J.
Published: September 2008

The morphology, biochemistry, and phenology of Claytonia lanceolata Pursh (Portulacaceae) was examined in western Washington and an analysis was made of associated vegetation and soils. Contrary to earlier taxonomic considerations, the results of this study do not support specific or subspecific separation of the two color forms (yellow and white). Two significantly different populations were revealed, however, based on size characters. These populations were also correlated with different community types and to a lesser extent soils, although detailed analysis of the chemical and physical properties of the A horizon showed intrapopulational variation to be at least as great as that between populations. Finally, the question of ecotypic distinction of the two population types is discussed.
Form and action of a protease in cotyledons of germinating peanut seeds
Authors: Mainguy P. N. R. , Huystee R. B. van , Hayden D. B.
Published: September 2008

The extract from cotyledons of 6-day-old peanut seedlings contained an enzyme that decomposed the chromogenic substrate N-benzoyl-D,L-arginine-p-nitroanilide (BAPA). The enzyme was purified by ammonium sulfate precipitation, pH adjustment, and anion-exchange chromatography. The molecular weight was found to be 60 000 as estimated from the Stokes radius obtained by gel filtration on Sephadex G 200. Its temperature response curve showed optimal activity between 25 and 36° and its pH optimum was 7.4. Anion-exchange chromatography as well as polyacrylamide gel electrophoresis of the purified extract resulted in two distinct areas of activity with regard to BAPA hydrolysis. Inhibitor experiments revealed that the enzyme does not have sulfhydryl groups at its active site nor does it respond to specific trypsin inhibitors, but it was inactivated by diisopropylfluorophosphate. It is therefore likely that it is a serine-type peptidase.
Two simple labeling and data retrieval systems for herbaria
Authors: Argus George W. , Sheard John W.
Published: September 2008

Two systems using simple computerized procedures to assist in the preparation of herbarium labels and to store and retrieve herbarium label data are described. The systems include programs to (1) maintain and update check lists; (2) print herbarium labels, punch summary data cards for each collection, and list species for each locality; (3) produce species distribution maps; and (4) list summary data cards according to taxa and geographic localities. The systems are flexible and economically competitive with manual methods of preparing herbarium labels and compiling lists and distribution maps. The systems have the advantage of requiring computer equipment (IBM 029 keypunch and IBM 360 computer) that is generally available at most university computer centers and at government laboratories.
On the metabolism of Aspergillus terreus on ammonium nitrate at different pH values
Authors: Naguib Kaiser , Younis A. Elbaz , Elessawy A. A.
Published: September 2008

One-week-old fungal mats of Aspergillus terreus Thom were fed with buffered Dox's liquid medium containing ammonium nitrate as nitrogen source and adjusted to six different pH values, namely, 3.0, 3.8, 5.4, 6.8, 8.4, and 10.0. Ammonium nitrogen and nitrate nitrogen absorption and utilization, sugar absorption, respiration, and growth were followed over a period of 72 h at 24-h intervals.Ammonium and nitrate were absorbed at all pH values tested, nitrate being preferentially absorbed at the lower, but ammonium at the higher pH values. Low absorption and utilization of nitrogen occurred at the lowest and highest pH values. Optimum pH for sugar absorption was that for nitrogen absorption, though the former was more sensitive to change of pH than the latter. Rate of respiration was affected by sugar and nitrogen absorption. It was optimum at the same optimum for these two processes.There was release of nitrogen from the mycelial cells to the external medium at all pH values tested, but highest release occurred under different pH conditions and was independent of whether ammonium or nitrate absorption was prevailing.In the fungal mats, more soluble nitrogen and less protein were found at the lowest and highest pH values, while less soluble nitrogen and more protein were found at the optimum pH range; a difference apparently more related to pH than to whether ammonium or nitrate was being absorbed.
Circadian rhythms of dark respiration, flowering, net photosynthesis, chlorophyll content, and dry weight changes in Chenopodium rubrum
Authors: Chia-Looi Ah-Sing , Gumming Bruce G.
Published: September 2008

There are circadian rhythmic changes in dark respiration, net photosynthesis, chlorophyll content, and dry weight in Chenopodium rubrum, ecotype 60°47′ N, 137°32′ W. The rhythm in dark respiration has a period of about 27 h and its phasing is quite closely correlated with the rhythm in flowering response, which has a period of about 30 h. A close similarity in the periodicity (21 h) and phasing of the rhythms in net photosynthesis and chlorophyll content suggests that the photosynthetic rhythm may be partly attributed to rhythmic changes in chlorophyll content. The rhythmic changes in dry weight, with a period of 18 h, could be due to a rhythm in dark fixation of carbon dioxide. The possible relationship of rhythmicity in these processes to other circadian rhythms that occur in C. rubrum is discussed. The concurrent existence of various rhythms in biochemical and physiological processes that differ in period and phase within a single ecotype of C. rubrum clearly reflects the possible involvement of metabolic activity in circadian rhythms.
Photosynthetic rates in relation to nitrogen recycling as an adaptation to nutrient deficiency in peat bog plants
Authors: Small Ernest
Published: September 2008

Fifteen species growing in a raised sphagnum peat bog were compared with 13 non-bog species with respect to their light-saturated net photosynthetic rate, and the content of N, P, and K within their foliage and leaf litter. Bog species were found to reabsorb significantly more nitrogen from their foliage preceding leaf fall than non-bog species. An estimate of the potential photosynthate which the species could manufacture during the time a given unit of nitrogen remained in the plant, before being lost through leaf fall, was calculated for the 28 species. The values found averaged 235% higher for the bog evergreens than for the bog deciduous species, and about 60% higher in the bog deciduous species than in the non-bog deciduous species. The hypothesis is advanced that the increased time available to use nitrogen photosynthetically before it is recycled is adaptive in bog plants, especially in evergreens, because of the difficulty in acquiring nitrogen from the extremely nutrient-deficient bog substrate.
The influence of cytokinins on genetic tumor formation
Authors: Ames Ira H.
Published: September 2008

Young seedlings of two tumor-prone Nicotiana amphiploids, grown aseptically on nutrient medium, were treated with either N6-benzyladenine or kinetin. The incidence of tumor formation was scored for 18 days subsequent to exposure. These cytokinins markedly accelerated the rate of tumorigenesis in both amphiploids. The results are discussed in relation to the problem of the trigger mechanism for tumor induction in Nicotiana species hybrids.
The influence of small applied electrical currents on Na, K, and Cl fluxes in Nitella translucens
Authors: Williams E. J. , Munro C. , Fensom D. S.
Published: September 2008

The changes of influx and efflux of Na, K, and Cl were studied in Nitella in artificial pond water (APW) under varying current densities below 1.3 μamp cm−2. The electric current seemed to act only on the passive ion influx and K efflux. Cl influx was insensitive to applied current. Na influx normally carried about 1/5 of the current, K much less unless the K concentration of the APW was increased. The relative percentage of each ion carrying the current at the positive end of the cell was readily altered by changes in K concentration or pH. It is presumed that H ion is also involved. In our experiments, low current densities below 0.7 μamp cm−2 gave no detectable effect on K, Na, or Cl effluxes at either end of the cell. Thus in electroosmotic experiments, Na influx at the positive end of the cell is an important flux, while K efflux is important at the negative end.Microinjection of tracer into the vacuole of Nitella is a feasible technique. Once isotopes have penetrated the cell membrane, they seem to move to some extent independently of each other.
Photosynthetic growth of tobacco cells in liquid suspension
Authors: Chandler M. Trevor , Marsac Nicole Tandeau de , Kouchkovsky Yaroslav de
Published: September 2008

Two clones of Nicotiana tabacum in liquid suspension culture were grown photosynthetically using air plus 2% CO2 as carbon source, and agitation. In general, the transfer from heterotrophic to autotrophic growth in these cells was accompanied by an increase in the concentration of photosynthetic pigments, an increase in the N, C, and H contents and in the N:C ratio, an increase in the photosynthetic oxygen evolution capacity, and a decrease in the respiratory rate. The limiting factors are discussed.Several clones were also grown photosynthetically on agar slants and the development of their photosynthetic pigments studied. Results showed that one cannot accurately predict the photosynthetic capability of tobacco cells from their appearance in heterotrophic culture conditions.
Terrestrial occurrence of some aquatic hyphomycetes
Authors: Bandoni Robert J.
Published: September 2008

By submerging leaves in sterile distilled water, large numbers of floating conidia of the tetraradiate and sigmoid types were observed. The conidia were most abundant on decayed leaves of angiosperm trees; all leaves were collected from high, well-drained sites at some distance from streams or other water bodies. Species of the following freshwater hyphomycete genera were among those obtained in pure culture: Alatospora, Articulospora, Flagellospora, Ingoldia, Tetracladium, Tricellula, Tricladium, Varicosporium, and Volucrispora. Conidia of other types, including both tetraradiate and sigmoid forms, were observed but not isolated. The abundance of the conidia in terrestrial habitats suggests that some of these fungi are primarily terrestrial organisms. Local dispersal of the conidia appears to occur on the film of water covering leaves and other plant debris.
Taxonomic status of Neurospora xylopiae
Authors: Davis E. E. , Jong S. C.
Published: September 2008

The type culture of Neurospora xylopiae Ram, ATCC 22259, has been studied. It is homothallic and lacks a conidial state. Comparative studies of this culture with the type cultures of all other homothallic non-conidial neurosporas indicate that N. xylopiae and N. dodgei are identical. Thus the name N. xylopiae Ram, 1968, is a later, facultative synonym of N. dodgei Nelson and Novak, 1964.
Studies on the relationships and evolution of supraspecific taxa utilizing developmental data. 1. Stipa lemmonii (Gramineae)
Authors: Maze Jack , Bohm Lesley R. , Beil Charles E.
Published: September 2008

This is a study of floret development and embryology of Stipa lemmonii (Vasey) Scribn. as a means of assessing its relationships and evolution. There is an advantage to using developmental data for it allows one to break complex structures down into developmental units. These developmental units can be compared and thus more characters can be analyzed. The lemma, palea, ventral lodicule, and carpel of S. lemmonii are leaf-like (sensu Sattler 1966, 1967) in initiation and early development. The stamens are stem-like and the ovule develops from the floret apical meristem. The ovule is interpreted as being cauline. The ovule is hemianatropous and pseudocrassinucellate. The inner integument delimits the micropyle. The integuments are ephemeral except for the inner layer of the inner integument. Embryo sac development is Polygonum type. Both synergids undergo change before entry of the pollen tube and the pollen tube appears to empty into the larger synergid. The antipodals are proliferated. The endosperm is at first free nuclear. Developmental features of S. lemmonii were compared with developmental features of S. tortilis, Oryzopsis miliacea, and S. hendersonii. The last is a species which hybridizes with S. lemmonii. Thirty-five characters were abstracted from the developmental data and were analyzed statistically. The results indicated that S. lemmonii and S. hendersonii are most closely related, and that these two plus S. tortilis form a group distinct from O. miliacea. The individual differences between taxa show gradation in the degree of difference. This is taken to indicate that the evolution of differences, and the evolution of taxa, is the result of the accumulation of many minor differences. Developmentally, plants are very simple, especially as compared with higher animals. Because of this, it is difficult to make generalizations about the "basic nature" of a plant structure using developmental data. Flowers seem best interpreted as functional units. This allows one to accept the concept that flowers in general are polyphyletic, a concept that is indicated by objective analysis of the data.
Abscisic acid protects bean leaves from ozone-induced phytotoxicity
Authors: Fletcher R. A. , Adedipe N. O. , Ormrod D. P.
Published: September 2008

Abscisic acid treatment of primary bean leaves caused a partial closure of stomates and thus considerably reduced the phytotoxicity of ozone. The symptoms of ozone-induced phytotoxicity in the water-treated leaves are a marked decrease in chlorophyll and slight decreases in the levels of protein and RNA. The evidence indicates that ozone injury to leaves is not metabolically related to normal leaf senescence.
Carbohydrate changes in seeds within McIntosh apples held at 1–2 °C during storage
Authors: Taper C. D. , Chong Calvin , Liu P. S.
Published: September 2008

Apple (Mains pumila Mill.) seeds were removed at 30-day intervals from McIntosh fruits held for 6 months at 1–2 °C. Chromatographic analysis of ethanolic extracts from samples including both endosperm and embryo and samples of seed coat showed the presence of considerable quantities of sucrose in all samples throughout the entire period, although sorbitol and reducing sugars were not detected. In the seed coat, the concentration of sucrose (mg/g fresh weight) increased between 30 and 120 days from 22.78 to 38.23, after which there was a progressive decrease to 22.35 at the end of the storage period. In the endosperm–embryo samples, the concentration of sucrose increased gradually between 30 and 90 days from 66.72 to 71.15, followed by a rapid decrease, which resulted in a relatively low level of 29.50 at the end of the storage period. Small quantities of stachyose were found in all samples during storage, although raffinose was detected only in the endosperm–embryo samples during the first 60 days.
Transpiration of Atriplex confertifolia and Eurotia lanata in relation to soil, plant, and atmospheric moisture stresses
Authors: Moore Russell T. , Whiter Richard S. , Caldwell Martyn M.
Published: September 2008

Atriplex confertifolia and Eurotia lanata plants were studied in the field and laboratory under controlled conditions of temperature and vapor pressure deficit with uniform wind speed and light intensity and various levels of water stress. Multiple regression analysis indicated that under both field and laboratory conditions, vapor pressure deficit and water stress were significant factors influencing transpiration. Phenological stage was also a major factor in the transpirational relationships of both species in the field. Transpiration rates under comparable conditions tended to be higher for Eurotia than for Atriplex on a leaf dry weight basis with less pronounced differences on a leaf area basis. However, in the latter part of the summer, transpiration rates of Eurotia decreased markedly while Atriplex tended to maintain active transpiration. Under laboratory conditions both species exhibited transpiration at plant moisture stress values as great as 115 bars.
Conidium ontogeny in hyphomycetes. Monilia state of Neurospora sitophila and Sclerotinia laxa
Authors: Hashmi M. H. , Morgan-Jones G. , Kendrick B.
Published: September 2008

Conidium ontogeny in the Monilia state of Neurospora sitophila and Sclerotinia laxa is analyzed by time-lapse photomicrography, and nuclear configurations occurring during conidiogenesis in the former are described.
Nuclear distribution and behavior in Thielaviopsis basicola
Authors: Huang H. C. , Patrick Z. A.
Published: September 2008

A cytological investigation of four biotypes of Thielaviopsis basicola isolated from field soil and of three cultural variants revealed that the hyphal cells, conidiophores, endoconidia, and chlamydospores are regularly uninucleate except those cells in which nuclear division or nuclear migration has occurred.The nucleus in the end cell of the conidiophore divides mitotically and successively after cell division to produce a chain of uninucleate endoconidia. During the formation of chlamydospores, a daughter nucleus migrates from the mycelial cell into the chlamydospore primordium. This primordium later forms a one-celled chlamydospore. If the chlamydospore consists of more than one cell, all the nuclei in the cells are derivatives of the nucleus in the primordium.Nuclear migration from one cell to another was observed to take place by means of anastomosis and (or) through septal pores of the mycelia. Anastomosis occurs between mycelia, between endoconidia, and between a mycelium and an endoconidium.The entire process of mitotic division occurs within an intact nuclear envelope. An intranucleate spindle was demonstrated in dividing nuclei in living preparations. Stained preparations revealed that there are four chromosomes in T. basicola.
Crown deterioration and reduced growth associated with excessive seed production by birch
Authors: Gross H. L.
Published: September 2008

In 1967 yellow birch, Betula alleghaniensis Britt., and white birch, B. papyrifera Marsh., developed extremely large seed crops in Ontario. Foliage was dwarfed or missing in the heavily seeded portions of tree crowns. Buds did not develop on the terminal portions of most branches, and in 1968 branches died back to the point where buds were available for growth. Terminal growth and diameter growth were reduced for both species in 1967, and terminal growth by yellow birch continued at a reduced rate in 1968. Terminal growth and bud production were inversely related to the amount of fruiting. Similar conditions prevailed on some yellow birch in 1970.Yellow birch was more seriously affected, and in most mature stands dieback averaged 20 to 50 cm. White birch was not affected to this extent; however, some trees in most mature stands suffered extensive dieback.
Encirclement of the oogonial stalk by the amphigynous antheridium in Phytophthora capsici
Authors: Stephenson L. W. , Erwin D. C.
Published: September 2008

Microscopic observations of oogonia and amphigynous antheridia of Phytophthora capsici at several stages of development indicated that the antheridial initial encircled the oogonial initial. Observations of the antheridium in different phases of encirclement, both polar and lateral views, indicate that the oogonial initial does not penetrate the antheridial initial as classically described.
Interaction of cytokinin, auxin, and gibberellin on peroxidase isoenzymes in tobacco tissues cultured in vitro
Authors: Lee T. T.
Published: September 2008

Peroxidase in tobacco callus tissue (Nicotiana tabacum, cv. White Gold) was resolved into three groups of isoenzymes by polyacrylamide gel electrophoresis, and a combined action of cytokinin, auxin, and gibberellin in their formation was clearly demonstrated. The most significant change was in a group of fast-migrating isoperoxidases, the development of which required both kinetin and indoleacetic acid. Kinetin was most stimulatory at 0.2 μM but became inhibitory with increasing concentrations. Indole acetic acid was effective at concentrations from 0.1 to 100 μM with an optimum at 10 μM. With both kinetin and indoleacetic acid at optimal concentrations, addition of gibberellic acid further increased the contents of the fast migrating isoperoxidases, but it was inactive in the absence of indoleacetic acid or in the presence of kinetin in 5 μM or higher concentrations. Cycloheximide, actinomycin D, and abscisic acid inhibited the formation of the fast-migrating peroxidases. Formation of the fast-migrating isoperoxidase in the tissue was associated with tumor-type growth.2,4-Dichlorophenoxyacetic acid had a dual effect on peroxidase; at low concentrations (0.1 to 1 μM) it promoted a fast-migrating isoperoxidase; at high concentrations (10 to 100 μM) it inhibited the fast-migrating isoperoxidase but caused a significant increase in other isoperoxidases of lower electrophoretic mobilities.
Development of the pistillate flower of Populus tremuloides following controlled pollination
Authors: Fechner Gilbert H.
Published: September 2008

Quaking aspen branches bearing female inflorescences were forced, artificially pollinated, and grown in water in the laboratory at 25 °C. The pistillate flowers developed normally to produce normal seeds in about 2 weeks. Sectioned material, which had been fixed at different times before and after pollination, revealed that the megagametophyte was in the four-nucleate stage at receptivity of the stigmas, and that it developed through the stages that Nagaraj (1952) described for natural material. Fertilization probably occurred between 72 and 120 h after pollination. Unfertilized ovules within ovaries containing one or more fertilized ovules developed normally for 1 week after pollination, but they began to degenerate soon thereafter.
Histology and ultrastructure of oat blue dwarf virus infected oats
Authors: Zeyen R. J. , Banttari E. E.
Published: September 2008

The oat blue dwarf virus is a small spherical virus (28–30 nm) in diameter and is obligatorily transmitted by the aster leafhopper Macrosteles fascifrons Stål. The virus causes abnormalities in the phloem development of infected plants. Hyperplasia and limited hypertrophy of phloic procambium, in a given procambial strand, begin only after the maturation of the first protophloem sieve-tube element in that particular localized area. The majority of phloem elements produced in hyperplastic areas are parenchymatous, have truncated end walls, and lack sieve plates. Electron-microscopic observations substantiated the hypothesis that the virus was phloem-limited by revealing virus particles only in phloem elements. The greatest accumulation of virus particles was observed in the region between immature and fully vacuolated phloem elements, implicating virus synthesis in immature elements. Crystals of virus particles were often large enough to be seen by light microscopy.
Dicoccum Corda
Authors: Hughes S. J. , Pirozynski K. A.
Published: September 2008

Dicoccum Corda, and its type species D. minutissimum are considered to be nomina ambigua. There has been no consistency in the application of the name Dicoccum even by Corda, who described seven species in the genus; these now are considered to belong to at least five different genera of Fungi Imperfecti. Twenty other taxa in the genus are enumerated and shown to belong to 14 additional genera of Fungi Imperfecti. Redispositions include Fnsicladium lathyrinum (Ell. & Gall.) comb. nov., F. psoraleae (Ell. & Barth.) comb. nov., Septoidium glaziovii (Allesch.) comb. nov., Spilocaea nebulosa (Ell. & Everh.) comb. nov., and Triadelphia inquinans (Sacc.) comb. nov.
The effects of nitrate, nitrite, and ammonia on photosynthetic carbon metabolism of Acetabularia chloroplast preparations compared with spinach chloroplasts and whole cells of Acetabularia and Dunaliella
Authors: Winkenbach F. , Grant B. R. , Bidwell R. G. S.
Published: September 2008

Nitrogen was supplied in the form of nitrate, nitrite, or ammonium ions to whole cells of Dunaliella tertiolecta, to whole cells and chloroplast preparations of Acetabularia mediterranea, and to spinach chloroplasts, while they were photosynthesizing in 14CO2. The 14C labeling patterns in these experiments provide information on several aspects of the photosynthesis, nitrogen metabolism, and physical properties of these systems. The rates and products of photosynthesis are affected in different ways by different ions, depending on the penetration of each ion, its toxicity, and on the ability of the system under test to synthesize amino acids. Thus the ions that penetrate spinach chloroplasts, while they may inhibit photosynthesis, do not affect the distribution of 14C among photosynthetic products because no amino acids are formed. The large differences in behavior between Acetabularia whole cells and chloroplast preparations from these cells suggest that the membrane structure surrounding cytoplasmic droplets in the latter may be tonoplast rather than plasmalemma in origin.
Mitosis in three hyphomycetes
Authors: Hashmi M. H. , Kendrick Bryce , Morgan-Jones G.
Published: September 2008

Vegetative nuclear division in the Chalara state of Thielaviopsis paradoxa, Trichothecium roseum, and Cladobotryum variospermum was studied by standard staining techniques. In T. paradoxa the chromatinic material and nucleolus divide by elongation and constriction comparable to that observed in phycomycetes. The spindle, if any exists, must be intranuclear and not discernible by light microscopy. In T. roseum and C. variospermum successive stages of mitosis accompanied by thin spindles were observed. A deeply staining lateral granule or 'centriole equivalent' is seen at the perinuclear area during interphase. Metaphase and anaphase configurations peculiar to ascomycetous nuclei are observed in T. roseum and C. variospermum.
Formation de nodules racinaires axéniques chez Alnus crispa var. mollis
Authors: Lalonde Maurice , Fortin J.-André
Published: September 2008

A culture medium promoting the in vitro nodulation of Alnus crispa var. mollis Fern. was established. Under well-defined growth conditions, a minimum inoculum of about 1 μg of fresh nodule per plant was sufficient to promote good nodulation of the host plant. Using the suspension–dilution technique combined with inoculation tests, it was possible to eliminate progressively endogenous contaminants and to obtain axenic nodules. These nodules are now being used in attempting to isolate the causal organism of the nodule.
The excretion of organic nitrogen by marine algae in batch and continuous culture
Authors: Newell B. S. , Dalpont G. , Grant B. R.
Published: September 2008

Production of varying amounts of dissolved organic nitrogen has been demonstrated in cultures of eight species of marine algae. The material appears to be polypeptide. Continuous culture experiments with two algal species showed that production of this organic material was not increased by stress in the form of changes in growth rate, light, carbon dioxide, or pH. It was increased when the continuous cultures were allowed to stagnate.
Survival of Xanthomonas citri in the bark tissues of citrus trees
Authors: Goto Masao
Published: September 2008

By leaf infiltration technique and by isolation method, the causal bacterium of citrus canker, Xanthomonas citri, was detected from discolored bark tissues of trunks, low scaffold limbs, and lateral branches of adult trees of lemon (Citrus limon, variety Lisbon), Natsudaidai (C. natsudaidai), and Unshu (C. unshu, variety Sugiyama). The pathogen was detected from 32% of the bark tissues taken from lemon trees, 15% from Natsudaidai, and 10% from Unshu. These isolation frequencies as well as the bacterial populations detected from the tissues correlated with degree of susceptibility of the twigs to citrus canker. Such discolored bark areas were considered to be the old canker lesions formed on the twigs in the seedling stage. In Unshu trees, the bacterium was also detected with high frequency but low populations from 6-month- to 3-year-old healthy-appearing green twigs, although any visible symptoms were not subsequently produced on them. In recovery experiments, large numbers of X. citri cells were isolated 3 years after inoculation, from the bark of the trunk of a 12-year-old lemon tree.
The effects of aflatoxin B1, citrinin, and ochratoxin A on amino acid uptake and incorporation by cucumber
Authors: White Audrey G. , Truelove Bryan
Published: September 2008

Both aflatoxin B1 and citrinin, in light and darkness, inhibited leucine uptake and its incorporation into protein by cucumber cotyledon disks. Aflatoxin was more inhibitory in the light and both toxins showed increased inhibition with increasing concentration. At a concentration of 50 μg/ml, citrinin was more inhibitory to amino acid absorption than aflatoxin. Time-course studies showed that a pretreatment time of at least 2 h was necessary with aflatoxin to affect the subsequent incorporation of leucine; citrinin, on the other hand, was inhibitory when it was supplied together with the 14C-leucine. In darkness, ochratoxin A at 10, 50, and 100 μg/ml enhanced leucine uptake but did not affect its incorporation into protein.
Short day and cold as causative factors in the anthesis-like development of strobili of western red cedar (Thuja plicata)
Authors: Pharis Richard P. , Morf William
Published: September 2008

Short-day (SD) and low temperature (5 °C) treatments were tested separately to ascertain their contribution to the anthesis-like development of gibberellin-induced staminate and ovulate strobili of western red cedar (Thuja plicata Donn.). Low temperature, when given only for 8 weeks under long day (LD) where the daily sequence of photoperiod was kept continuously at 16 h resulted in expansion of 90% and 77% of the staminate and ovulate strobili respectively compared to 96% and 79% respectively where cold was given only during 8 weeks of SD in the sequence LD → SD → LD. Conversely, 8 weeks of SD given at warm temperature (19 °C) in the sequence of LD → SD → LD resulted in expansion of 9% and 1% of the staminate and ovulate strobili respectively. Thus, strobili of western red cedar can be said to have a cold requirement for normal anthesis-like expansion. In only a very small percentage of the strobili can SD (at least 8 weeks of SD) substitute for low temperature, and the low temperature treatment is effective regardless of photoperiod.
Histogenesis of fenugreek calli originating from hypocotyl explants
Authors: Gupta K. C.
Published: September 2008

Hypocotyl explants of fenugreek developed into calli by proliferation of cells in the pericycle region. Occasionally vascular parenchyma proliferated and reinforced the callus developing from the pericycle region. In rare instances calli developed solely from cortex. Meristemoids developed in the calli and each of them at maturity had peripheral layers of meristematic cells enclosing a centrifugally differentiating mass of tracheid-like cells.
Environmental control of apical dominance in Phaseolus vulgaris
Authors: McIntyre Gordon I.
Published: September 2008

When seedlings of Phaseolus vulgaris were grown under controlled conditions at a light intensity of 3200 ft-c, 60% relative humidity, and at nitrogen levels of 5.25, 52.5, and 210 ppm, growth of the buds at the cotyledonary node, which served as a measure of apical dominance, showed a positive correlation with the nitrogen supply and with the soluble nitrogen content of the hypocotyl. Increasing the nitrogen supply to 420 ppm caused a proportionate increase in soluble nitrogen content but no additional bud growth response. That the growth response was limited by water supply was shown by growing plants at 420 ppm nitrogen and relative humidities of 30, 60, and 90%. Each reduction in water stress, as measured by leaf relative turgidity, caused a highly significant increase in growth of the cotyledonary buds. Under high nitrogen, low water stress conditions, bud growth was markedly inhibited by reduction of the light intensity from 3200 to 700 ft-c.These results support the concept of nutrient competition as a major factor in the mechanism of apical dominance and also suggest that conflicting reports on the effect of externally applied growth-regulating substances on lateral bud inhibition may be due partly to environmentally induced differences in nutritional status of the experimental plants.
Zinc toxicity in hydroponic culture
Authors: Rauser W. E.
Published: September 2008

The symptoms of zinc toxicity in beans, soybeans, and corn are described. In beans and soybeans these include the deposition of a red-brown pigment in parenchyma cells of the cortex, xylem and phloem of veins, petioles, and stems. The pigment fills some parenchyma cells completely but is confined to the cell walls of others. The xylem vessel lacunae remain free of the pigment. Extensive disorganization of cortical cells is evident in veins. The pigment is suspected to be a polyphenolic substance of unknown biochemical origin.
Mycoarctium, a new coprophilous genus in the Thelebolaceae
Authors: Jain Kanti , Cain R. F.
Published: September 2008

Mycoarctium ciliatum is described and illustrated as a new species and a new genus found on deer dung from Colorado, U.S.A. The small, very light brown apothecia have numerous, rigid, septate hairs. The asci are eight-spored, clavate, without an operculum, and evanescent. The ascospores have reticulate ridges and are not forcibly discharged.
A new species of Pythium from Wisconsin and Florida isolated from carrots
Authors: Pratt R. G. , Mitchell J. E.
Published: September 2008

Pythium sulcatum n. sp. was isolated from carrots with browned and forked roots grown in muck soils from Wisconsin and Florida. It is primarily distinguished by small oogonia and oospores and by antheridia which are variable in shape and frequently adorned with single or multiple transverse furrows and folds, for which the species is named. Zoospores are rarely produced; vesicles always arise from filamentous sporangia indistinguishable from vegetative hyphae. Vegetative hyphal bodies vary in shape and are outnumbered by sexual bodies on most media. Radial growth rates of P. sulcatum on potato dextrose agar are slower than those of P. irregulare, P. paroecandrum, and P. sylvaticum over a wide temperature range, and P. sulcatum may easily be distinguished from these species on that basis.
The development of tolerance to dodine in Venturia inaequalis
Authors: MacNeill B. H. , Schooley Janice
Published: September 2008

The screening in vitro of large numbers of conidia of Venturia inaequalis against the selection pressure of dodine revealed a spontaneous mutation rate to dodine tolerance of about 1 in 106 conidia screened. Mutants cultured as mycelial disks grew 53–92% as well on a medium containing 0.5 ppm dodine as on a dodine-free medium. A comparable level of tolerance was developed by the wild type after a period of continuous vegetative growth on the dodine medium, but, unlike the mutants, the wild type lost its tolerance when cultured briefly on medium containing no fungicide. One of the seven mutants exhibited the capacity to adapt to increasingly higher concentrations of dodine. It is postulated that the events leading to the development of tolerance to dodine in V. inaequalis may be not only mutational and stable, but also adaptive and reversible, or a combination of both mechanisms.
Trace element content of soils and plants from the Selwyn Mountains, Yukon and Northwest Territories
Authors: Doyle P. , Fletcher W. K. , Brink V. C.
Published: September 2008

The relationships between molybdenum, copper, zinc, and manganese contents of soils and plants from a pristine region of northwestern Canada are reported. Abnormally high plant molybdenum values (up to 52 ppm dry weight) are associated with a diverse flora growing on neutral or slightly alkaline molybdeniferous soils derived from shale–limestone parent materials. On acidic, molybdenum-rich soils and soils with normal molybdenum content, levels in plants seldom exceed 0.2 ppm.Data for copper in vegetation indicate low, rather uniform values for a variety of soil conditions. Zinc, however, shows appreciable differences in uptake, with the greatest accumulation in woody, deciduous species. Manganese uptake, which is also greatest for woody species, decreases with increasing soil pH. Caribou moss (Cladonia alpestris (L.) Rabenh.) is notably low in all four trace elements.
The sexuality and population structure of Pythium sylvaticum
Authors: Pratt Robert G. , Green Jr. Ralph J.
Published: September 2008

Sexual characteristics of 36 isolates of Pythium sylvaticum were investigated. Fourteen of 15 heterothallic males were also homothallic while only 2 of 21 females were homothallic. Four male and five female groups of isolates were delineated by similar reacting patterns under five different temperature and light conditions. Mature oospores formed in crosses varied with both male and female isolates and were not correlated with sexual strengths of reacting isolates. Three-to-one ratios of males to all other progeny occurred among 198 single-oospore progeny of two crosses involving non-homothallic parents. Most progeny were also homothallic. A pattern for the distribution of sexual characteristics of natural populations of P. sylvaticum is proposed based on characteristics of the 36 isolates.
Endoascosporic cells in three pyrenocarpous lichen genera
Authors: Morgan-Jones G.
Published: September 2008

Hyaline, smooth-walled, endoascosporic cells are reported in the lichen genera Anthracothecium Hampe, Pyrenula Ach. em. Massal., and Trypethelium Spreng.
Glycoprotein II in developing and germinating bean seeds
Authors: Racusen David , Foote Murray
Published: September 2008

Glycoprotein II increased most rapidly as growing bean seeds became grey and neared their maximal length and fresh weight. During germination this protein decreased most rapidly between 7 and 10 days.
Histochemical changes occurring at the seedling shoot apex of Pinus radiata
Authors: Riding Richard T. , Gifford Jr. Ernest M.
Published: September 2008

Histochemical tests on Pinus radiata shoot apices throughout the growing season showed marked changes in cell constituents. Reserve proteins and lipids were high in dormant embryos. Following imbibition, starch occurred throughout the apex and tannins were evident after the cotyledons emerged from the seed coat. Intensity of stains for DNA, RNA, and nucleohistones increased first at the flanks of the apex. At 84 days DNA, RNA, and histones displayed a zonate distribution pattern. Total proteins and carbohydrates were distributed fairly uniformly.The distribution of enzyme activity also varied. Initially acid phosphatase (AP) and succinic dehydrogenase (SDH) activities were high throughout the apex. A decrease of AP and SDH activity in the apex preceded epicotyl elongation. At 84 days AP activity differed in various regions of the apex; SDH was fairly uniform throughout the central, apical, and peripheral zones. Staining for peroxidase was evident first around aleurone grains and along cell walls after imbibition. With the onset of needle formation, staining was concentrated in subsurface cells. At 84 days peroxidase activity was concentrated in subsurface cells of the peripheral zone and in the rib meristem.The results of this study indicate that the full apex is metabolically active during vegetative growth and all regions are probably involved in the determination of vegetative form.
Contribution à la tératologie des Chèvrefeuilles et au problème des fusions
Authors: Vieth Joachim , Lamond Michel
Published: September 2008

In this paper, the authors deal with the morphological features of 10 abnormal branches of honeysuckle. The studied forms are of two different types. The first is illustrated by five specimens collected on a single hybrid bush called Lonicera nigra × orientalis. All of these show unusual union between restricted portions of different leaves. The arrangement of the fused parts permits one to infer that gamophylly, in this example, results indubitably from a real ontogenetic (postgenital) union. Concaulescence is the second kind of anomaly, shown in the samples from various cultivars belonging to the Lonicera tatarica complex. The occasional occurrence of accessory serial buds between the concrescent axes suggests that ontogenetic fusion could give rise also to such structures. In some particular instances, however, it is possible that unusual intercalary growth is combined with the first process.
Extractives associated with wound response of lodgepole pine attacked by the mountain pine beetle and associated microorganisms
Authors: Shrimpton D. M.
Published: September 2008

Extractive changes that occur in the sapwood of lodgepole pine (Pinus conforta Dougl. var. latifolia Englm.) in response to attack by the bark beetle (Dendroctonus ponderosae Hopk.) and associated microorganisms were studied. The most striking change was a large increase in total terpene to levels well above that normally observed in sapwood or heartwood. Free acids, phenolics, and neutral components increased to a final concentration about the same as that in heartwood, but at a much slower rate than terpenes. Free sugar levels decreased. With the single exception of β-phellandrene no unusually high or unusually low levels of any one compound were observed in the wound response. All components found in the wound response were normal constituents of heartwood.
Ontogeny and histochemistry of the intermediate and reproductive apices of Cosmos bipinnatus var. Sensation in response to gibberellin A3 and photoperiod
Authors: Molder Marje , Owens John N.
Published: September 2008

Plants of Cosmos bipinnatus Cav. ‘Sensation’ (a quantitative short-day plant) were grown under continuous conditions favorable or unfavorable for flowering, and some plants in each group were treated with gibberellic acid (GA3). Floral apices of Cosmos are formed by the transition of previously vegetative apices. The vegetative apex shows a cytohistological zonation pattern superimposed upon a tunica–corpus organization. The vegetative apex passes into an intermediate stage presumed typical of many plants held under non-inductive conditions. This stage is marked by many cytological features characteristic of both reproductive and vegetative apices but leaves continue to be produced. The presence of the intermediate stage accounts for conflicting results obtained in physiological studies since there is great variation in response rate depending on age of plant and the stage of the apex at the start of an experiment. This stage is followed by a typical transitional stage marked by an increase in RNA content, increased mitotic activity, and a change in zonation. Elongation of the apex and internodes occurs followed by initiation of the involucral bracts and floret primordia, marking the beginning of the prefloral and inflorescence stages respectively.GA3 specifically induces Cosmos to flower under non-inductive conditions thereby influencing floral initiation in a facultative short-day plant. Microscopic examination of the rate of apical transition revealed that GA3 substituted effectively for short days but was not as efficient an inducer as were short days.
Genera coelomycetum. VIII. Rhabdogloeopsis Petrak and Rhabdogloeum Sydow
Authors: Raj T. R. Nag , Morgan-Jones G.
Published: September 2008

Rhabdogloeopsis balsameae (J. J. Davis) Petrak and Rhabdogloeum pseudotsugae Sydow, the type species of Rhabdogloeopsis Petrak and Rhabdogloeum Sydow respectively, are redescribed and illustrated. Emended generic diagnoses are provided.
Ballistospore discharge in Tilletiopsis minor
Authors: Pady S. M.
Published: September 2008

Ballistospore discharge in Tilletiopsis minor Nyland was studied in a growth chamber under various conditions using a Kramer-Collins Spore Sampler. Sporulation occurred on leaves of Althea naturally infected with Puccinia malvacearum, on inoculated healthy leaves of Althea, and on 11 other hosts. Under alternating dark (12 h, 90–94% relative humidity (RH)) and light (12 h, 80% RH) at 21 °C, sporulation occurred periodically, only when humidity was high. There was no evidence of an endogenous rhythm in continuous light or dark.
Manganese and zinc absorption with octylphenoxyethanol surfactants by soybean leaf tissues
Authors: Beauchamp E. G.
Published: September 2008

Soybean leaf disks were used to study the effect of ethylene oxide (EO) chain length in a homologous series of octylphenoxyethanol surfactants on Mn and Zn absorption while floating on solutions in which CaSO4 was either absent or present. Octylphenoxyethanol surfactants with EO chain lengths of 5, 7–8, 9–10, 12–13, and 30 ethylene oxide groups per molecule of surfactant were included in the study.Zn absorption was enhanced whereas Mn absorption was decreased in the presence of 0.5 mM CaSO4. However, the presence of CaSO4 had relatively little influence on the effectiveness of the surfactants in enhancing Mn or Zn absorption. In general, surfactants of intermediate EO chain length enhanced Mn or Zn absorption to the greatest extent. Triton X-114 (EO = 7–8) generally tended to cause the greatest enhancement.The surface tension generally increased as the EO chain length increased. As the surfactant concentration was increased from 0.075 to 0.75 mM, the surface tension decreased but then tended to increase as the surfactant concentration was increased further to 7.5 mM. The interfacial tension measured at a corn oil/surfactant solution interface generally decreased with EO chain length at the 0.075 mM surfactant concentration. However, the interfacial tension decreased and then increased as the EO chain length increased at the 0.75 and 7.5 mM concentrations. Neither surface tension nor interfacial tension values could be directly associated with enhanced Mn or Zn absorption by soybean leaf disks. Also, the hydrophile–lipophile balance of the surfactants was not directly associable with enhanced Mn or Zn absorption.