bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental bisection of Aquilegia floral buds cultured in vitro. I. The effect on growth, primordia initiation, and apical regeneration
Authors: Jensen Lawrence C. W.
Published: September 2008

Floral buds of different stages of development were bisected and cultured in vitro. Subsequent development of floral primordia and regeneration of new apices were observed and recorded by maintaining a continuous photographic record of individual buds. In this way it was possible to correlate the time required for apical regeneration, number of subsequent primordial whorls formed on intact and cut surfaces, and the development of bisected buds as compared to control buds. It was concluded that a greater number of floral primordia are predetermined in progressively older buds and that the oldest buds are incapable of apical regeneration.
The in vitro growth and metabolism of Acer saccharum tissue
Authors: Mathes Martin C. , Morselli Mariafranca , Marvin J. W.
Published: September 2008

Isolated sugar maple callus was grown on defined medium containing 0.2 kinetin and 2.0 ppm indoleacetic acid. Selected components of the basal medium were varied but did not result in increased tissue growth. The presence of 1, 5, or 25 ppm gibberellic acid in the culture medium did not increase the secretion of starch digesting materials by the tissue. The diameter of the starch digestion zone was not influenced by changing the acidity of the medium in the range of pH which supported tissue growth. The ability of isolated callus tissues from various species to digest extracellular starch was examined. It was found that equal amounts of various tissues do not possess an equal capacity for the in vitro secretion of extracellular materials, most probably enzymes, into the culture medium. It was found that isolated sugar maple tissue metabolized sucrose, galactose, and cellobiose while mannose and rhamnose were not used.Isolated sugar maple tissue which had been subcultured on the same medium for a long period was found to undergo nutritional changes which enabled the tissue to adapt to the medium. The starch-digestion enzyme activity of the tissue was found to increase when sugar maple tissue was placed on soluble starch medium.
The role of wound periderm in the resistance of eastern larch and jack pine to dwarf mistletoe
Authors: Tainter F. H. , French D. W.
Published: September 2008

Formation of wound periderm appears to be a common form of resistance reaction in the Arceuthobium pusillum – Larix laricina combination, based on previous observations and an extensive examination of two witches' brooms of this host. Not only is wound periderm common in spur shoots within witches' brooms, but it also apparently restricts the development of the endophytic system in branchlets composing witches' brooms. Branchlets within witches' brooms of Pinus banksiana infected with A. pusillum and A. americanum also produced wound periderm similar to that described in eastern larch, which may account for the relative scarcity of aerial shoots on this host and restricted development of the endophytic system.
Embryological features of taxonomic significance in the genus Nyssa
Authors: Tandon Shiv R. , Herr Jr. J. M.
Published: September 2008

The embryological investigation of Nyssa aquatica L., N. biflora Walt., and N. sylvatica Marsh. reported here clearly delimits similarities and variations among the three species. Such evidence supports the retention of Nyssaceae as a family apart from Cornaceae. The major distinctions between the two families occur in the differentiation of the megasporocyte, development of the nucellus, degeneration of defunct megaspores, and growth pattern of the megagametophyte. Major points of similarity between the two families are the occurrence of unitegmic, pendulous, anatropous ovules, a single hypodermal archesporial cell, unequal dyad cells, hooked synergids, polar nuclei fusing before syngamy, and cellular endosperm. These same features serve also to show that Nyssaceae belongs in the order Cornales rather than Myrtales as suggested by several workers.Strong evidence is provided for the recognition of N. biflora as a distinct species rather than a variety of N. sylvatica as previously proposed by several workers. Points of distinction between the two taxa are found in the shape of the ovule, growth pattern of the nucellar apex and integument, position of the nuclei in the four-nucleate megagametophyte, and the growth pattern of the megagametophyte.Embryological features further indicate a closer relationship between N. aquatica and N. biflora than between either one and N. sylvatica. The features of greatest similarity between N. aquatica and N. biflora are the shape of the ovule and megasporocyte, growth pattern of the megagametophyte, presence of hooked synergids, and the occasional occurrence of bisporic megagametogenesis.
The effects of malonate on absorption of water by root hairs of Avena sativa
Authors: Ahmad Mukhtar , Cailloux Marcel
Published: September 2008

The influence of a range of concentrations of malonate on the rate of water absorption by the root hairs of Avena sativa is investigated. Different results are obtained when malonate is applied on root hairs of various lengths. At higher concentrations (10−6, 10−7 M) inhibitory effects are predominant, resulting in the rapid death of the root hair or heavy excretion, whereas at lower concentrations (10−8, 10−9, 10−10 M) an increase in absorption rate indicates a direct participation of malonate in respiratory metabolism.A close relationship exists between the length or age of a root hair (amount of cytoplasm present in the root hair at the region of immersion) and the inhibitory effects of malonate. The survival period is long when the root hair is young or when cytoplasm is abundant.The evidence suggests that absorption of water by root hairs of Avena sativa is perhaps not osmotic, as metabolic energy seems to be directly involved in it, at least when the plant is deprived of foliage.
Notes sur la production, in vitro, de sporophores par Pholiota aurivella
Authors: Lavallée André , Lortie Marcel
Published: September 2008

The influence of light and other environmental conditions on the sporophore production was tested for Pholiota aurivella in the laboratory. Among different light sources tested, only sunlight, through the window, led to the production of complete sporophores in culture. The light stimulus must be given within the first 14 days following mycelium implantation. The number and size of sporophores increase with increasing nutrient concentration in the solid culture medium up to a level of 7% malt extract. Larger containers plugged with cotton are more favorable for the production of sporophores of normal size than smaller, hermetically closed containers.
A necessary name change for jack pine: Pinus divaricata in lieu of P. banksiana
Authors: Argus George W.
Published: September 2008

A literature review has corroborated the view that the name Pinus divaricata (Ait.) Dumont has priority over P. banksiana Lamb, as the correct name for jack pine.
Effect of inoculation of oats with paired combinations of barley yellow dwarf virus isolates
Authors: Halstead B. E. , Gill C. C.
Published: September 2008

The mean weight of seed per plant and the mean plant weight of oats inoculated jointly with a Rhopalosiphum padi-specific isolate and a Macrosiphum avenae-specific isolate of barley yellow dwarf virus or with the R. padi-specific isolate and a non-specific isolate, were significantly less than those of oats singly inoculated with the respective isolates. Values for these criteria for oats jointly inoculated with the M. avenae-specific and the non-specific isolates were intermediate between, or were greater than, those for singly inoculated oats. This was true whether inoculation with the individual isolates was made simultaneously or with an interval of 16 days between the two inoculations.When oats were inoculated jointly with two Schizaphis graminum-specific isolates, seed and plant weights were significantly less than on plants inoculated singly with each isolate.For each combination used, both isolates were transmissible to oats from jointly inoculated plants. It is inferred that interference occurred only between the M. avenae-specific and the non-specific isolates and that a synergistic response resulted with the other combinations.
Présence de Polysiphonia brodiaei sur la côte Atlantique du Canada
Authors: Lauret Michel
Published: September 2008

The author indicates the presence of Polysiphorzia brodiaei (Dillwyn) Greville, in the neighborhood of Halifax (Nova Scotia, Canada). The species thus exists on both sides of the northern Atlantic as well as on both sides of the northern Pacific and in the Mediterranean.
In vitro germination of black walnut pollen
Authors: Hall Geraldine C. , Farmer Jr. Robert E.
Published: September 2008

Black walnut pollen was germinated on liquid and agar-based media containing 20% sucrose, a requirement for germination and normal tube development. Boron (100 ppm boric acid) added to this medium slightly enhanced germination. Germination occurred only in dense (150+ grains/mm2) populations of pollen on the agar medium. This population effect was not overcome by the addition of Ca2+ to the medium, but germination in the sparse areas (< 30 grains/mm2) was occasionally promoted by high boron concentrations (600 ppm boric acid). Wide tree-to-tree variation in percentage of germination was observed.Vacuum-drying periods, ranging from 5 to 30 min, resulted in a gradual reduction of viability. Pollen was stored at −30C and −196C for 3 months without major loss of viability.
Structural and metabolic changes in the shoot apex in transition to flowering
Authors: Bernier Georges
Published: September 2008

This paper is a review dealing with the various structural and metabolic changes that have been described in the shoot apex in transition to flowering. Evaluation of the significance of these changes can tentatively be made only in cases where a, the timing of physiological events in the plant, particularly the time of movement of the floral stimulus, is reasonably well known; b, the timing and localization of events in the shoot apex are known.For each of the best known cases (Xanthium, Pharbitis, Sinapis, Lolium, Chenopodium), the temporal sequence of events in the target cells of the apical meristem is described and the sequences are compared. Three successive phases of general occurrence are distinguished.1. The evocation phase, including the events occurring at the presumed time of arrival of the floral stimulus at the meristem. During this phase, RNA and protein molecules essential to the flowering process are synthesized.2. The mitotic phase, characterized by the release in mitosis of cells that are in the postsynthetic G2 phase of the mitotic cycle.3. The morphogenesis phase, including the events leading to the production of flower buds.The essentiality and role of the phases are discussed in relation with current views on cell differentiation.
New genera of Onygenaceae
Authors: Malloch David , Cain R. F.
Published: September 2008

An emended description of the family Onygenaceae (Ascomycota) is presented and a key to the seven genera given. Two new monotypic genera are described: Ascocalvatia gen. nov., with the type species A. alveolata sp. nov., has white puffball-like ascocarps and cylindrical ascospores; Xynophila gen. nov., with the type species X. mephitalis sp. nov., has ascocarps clustered within a common tomentose layer. The remaining five genera of Onygenaceae, Aphanoascus Zukal, Arachnomyces Massee & Salmon, Dichotomomyces Scott, Onygena Fr., and Thermoascus Miehe are briefly discussed.
Inoculation of a nonhost tissue culture with Cronartium ribicola
Authors: Harvey A. E. , Grasham J. L.
Published: September 2008

Cultured tissues from Pseudotsuga menziesii (Mirb.) Franco were successfully inoculated with Cronartium ribicola J. C. Fisch. ex Rabenh. Typical intracellular haustoria were formed 60 days after inoculation. Invaded nonhost tissues were necrotic within 90 days, and dead within 120 days. Tissue cultures of either Pinus monticola Dougl. or P. menziesii had an attractant effect on nearby rust mycelium.
Relationships between production, nutrient accumulation, and chlorophyll synthesis in an Eleocharis quadrangulata population
Authors: Boyd Claude E. , Vickers David H.
Published: September 2008

Maximum standing crop in an Eleocharis quadrangulata population was estimated at 881 g dry wt./m2. Net daily productivity was highest during May when about 50% of the total standing crop was produced. Net productivity for the entire period of vegetative increase, April 1 to August 4, was 7.0 g/m2 per day. The accumulation of several nutrients, especially nitrogen, phosphorus, and potassium was proportionately more rapid than dry matter production during early spring growth. Net chlorophyll synthesis was also greater during early spring. Patterns of change in dry matter and chemical substances in the E. quadrangulata population were similar to those in populations of other emergent aquatic macrophytes.
New distribution records for 48 species of Polyporaceae in western Canada
Authors: Ginns James H. , Macrae Ruth
Published: September 2008

Forty-eight species of Polyporaceae are reported for the first time from the four western Provinces and Yukon and District of Mackenzie of the Northwest Territories. The number of species reported are from Manitoba 11, Saskatchewan 8, Alberta 20, British Columbia 10, Yukon Territory 4, and Northwest Territories (Mackenzie Dist.) 13.
The metabolism and subcellular organization of the jack pine embryo (Pinus banksiand) during germination
Authors: Durzan D. J. , Mia A. J. , Ramaiah P. K.
Published: September 2008

Water imbibed by jack pine seeds induced rapid oxygen uptake and over 95% germination. As cells of cotyledons expanded and divided the redistribution of carbohydrates, proteins, and nucleic acids, followed cytochemically, corresponded to changes in subcellular organization.In dormant cotyledons, cells lacked chloroplasts and were packed with lipid reserves, protein bodies, and amyloplasts. After 96 h of imbibing water, storage materials were consumed as new cytoplasm appeared and numerous polysome-like particles extended from the nucleus into the cytoplasm. Levels of acid-soluble nucleotides, RNA, and DNA increased up to the fourth day of germination coinciding with the completion of the first mitotic cycle. RNA was concentrated in phragmosomes and at the newly formed cell plates. Acidic proteins, found mainly in the protein bodies of dry cells, were now localized in nucleoli. Histones were associated mainly with chromosomes, although in dormant cells, reserve protein, rich in arginine, occurred in protein bodies Proplastids, which eventually developed into chloroplasts, remained close to the nucleus until most reserves in the cytoplasm were depleted.As cotyledons became independent of the nutrition of the female gametophyte, the cytoplasm of proliferating cells contained more mitochondria, a rough endoplasmic reticulum, ribosomes, golgi bodies, and chloroplasts with up to four starch grains. After 10 to 12 days, the cytoplasm appeared at the periphery of cell walls as a result of the accumulation of water in a large vacuole.
Occurrence and distribution of chytrids, chytridiaceous fungi, and some Actinomycetales from soils of Oregon, California, and Nevada
Authors: Booth Tom
Published: September 2008

Fifty-four species of chytrids, chytridiaceous fungi, and Actinomycetales in 18 genera are reported in 140 collections from 32 coastal and interior locations. Morphological details are presented for some species.
Do roots synthesize gibberellins?
Authors: Crozier A. , Reid D. M.
Published: September 2008

Removal of root apices from light-grown Phaseolus coccineus seedlings inhibited shoot growth. This inhibition was partially overcome by treatment with gibberellin A3. Extracts from control seedlings and seedlings without root apices were purified with G-10 Sephadex, chromatographed on silicic acid partition columns, and tested for GA-like activity with the 'Tan-ginbozu' dwarf rice and barley aleurone α-amylase bioassays. The major GA in control plants was GA1; traces of GA19 were also detected. Removal of root apices resulted in the disappearance of GA1 and the accumulation of GA19 in the leaves and apical buds and in the subapical root remnants. Gibberellin A1 levels in the cotyledons were unaffected by the removal of the root apices.The data are interpreted as indicating that root and shoot GA's are interrelated in that the GA1 in the shoot originates in the root system. Synthesis of the cotyledon GA1 appears to be independent of GA metabolism in the roots. A scheme is proposed that involves the recycling of GA's from shoot → root → shoot, with the shoot being the site of synthesis of GA19, which moves to the root where it is converted to GA1, which in turn is exported to the shoot. An important point in this scheme is that the shoot is the primary site of GA biosynthesis and the root is merely the site of a GA interconversion. Results of other workers indicating that roots are a site of GA biosynthesis are not equivocal and can be equally well interpreted in terms of a GA interconversion system.
Problematical taxonomic criteria in the Chytridiales: comparative morphology of 10 Entophlyctis sp. isolates
Authors: Booth Tom
Published: September 2008

The criteria generally used in distinguishing taxa among the Chytridiales are size and structure of the zoospores, sporangium wall ornamentations, discharge papillae and tubes, presence or absence and structure of apophyses, nature and structure of rhizoids and number and position of rhizoidal axes, thallus development and relation to the substratum, monocentricity or polycentricity, and operculation. A review of the literature, however, reveals that these criteria are not sharply defined but highly variable and unstable for purposes of exact identification. This variability has become evident from a study of 10 single spore isolates of an Entophlyctis species collected in western Canada and the U.S.A. and grown on pollen grains and a synthetic medium. A comparison of the variations common to all isolates relates this species to several different established species of the genus which grade into one another and result in only three valid taxa, E. apiculata, E. crenata, and E. reticulospora. Also, the variations of the isolates relate this Entophlyctis sp. to different genera, subfamilies, families, and series, and make various current taxonomic dispositions and concepts of little value.
The control of blooming in Sauromatum guttatum (Araceae) by darkness
Authors: Buggeln Richard G. , Meeuse Bastiaan J. D. , Klima John R.
Published: September 2008

When an inflorescence of Sauromatum guttatum Schott blooms, the spathe unfolds and exposes the spadix. After spathe-opening, the terminal portion of the spadix (appendix) undergoes a dramatic respiratory climacteric (RC) which is characterized by the production of copious quantities of CO2 and the concomitant warming of the appendix.In experiments conducted on inflorescences raised under continuous irradiation, we have shown that darkness is the environmental factor which triggers the blooming. The moment of the peak in CO2 (or heat) production during the RC was used as an index of blooming.The darkness which triggers the RC is "perceived" by the staminate flowers, borne on the spadix beneath the appendix. Darkness is also involved in (1) regulating the lag time between the inductive dark period and the moment of the peak in the RC, and (2) opening the spathe.
α-Ketobutyrate decarboxylase activity in Rhizoctonia solani
Authors: Quinn Robert M. , Strobel Gary A.
Published: September 2008

The anaerobic decarboxylation of α-ketoacids by a crude extract of Rhizoctonia solani was investigated using a manometer procedure. The possible importance of this enzyme in the metabolism of the fungus is discussed. The best substrate for the enzyme preparation was α-ketobutyrate. Thiamine pyrophosphate and Mg2+ were cofactors for the enzymic decarboxylation of α-ketobutyrate. The Km for α-ketobutyrate was 7.6 × 10−3 moles/1, and the energy of activation was 3980 calories. Optimum catalysis for the reaction was achieved at 32°, pH 6.2. Products of the action of the enzyme preparation on α-ketoacids were CO2 and the respective aldehyde. Decarboxylase activity was inhibited in the presence of Hg2+, Ag+, and norjavanicin.
Pigments, polysaccharides, and photosynthetic products of Phaeosaccion collinsii
Authors: Craigie J. S. , Leigh C. , Chen L. C.-M. , McLachlan J.
Published: September 2008

Zoospores of Phaeosaccion collinsii averaged 70 µ3 and contained total N 2.24 pg, DNA 0.19, and chlorophyll a 0.62 pg per spore. In addition, chl c, "cis"-β-carotene, fucoxanthin, and violaxanthin were principal pigments and a minor unidentified carotene was present.Photosynthetic rates of zoospores were 0.37 × 10−12 g C per spore per hour, or 0.59 mg C per mg chl a per hour at 5°. The principal products of photosynthesis were mannitol and a water-soluble glucan.Carbohydrates in the thalli were fractionated and evidence is presented for the presence of a laminarin-like glucan, mannitol, myo- and scyllo-inositols. Alginate was absent.The relationship of P. collinsii to other algal groups is discussed and it is concluded that its affinities lie with the Chrysophyceae.
Observations on the ascogenous system of Hypoxylon microplacum
Authors: Rogers Jack D.
Published: September 2008

The ascogenous hyphae of Hypoxylon microplacum originate from uninucleate secondary ascogonial cells. Asci are produced by way of croziers and directly from ascogenous cells. The implications of these results are discussed.
Characterization and classification of mycorrhizae of Douglas fir. II. Pseudotsuga menziesii + Rhizopogon vinicolor
Authors: Zak B.
Published: September 2008

A common tuberculate ectomycorrhiza of Douglas fir in the Pacific Northwest, described earlier by Trappe, is further examined and defined. Tubercles consist of an outer rind of aseptate, amber, thick-walled hyphae encasing tightly packed inner elements mantled with septate, hyaline, thin-walled hyphae. Reported as a Phycomycete and a Basidiomycete, respectively, the two hyphal forms actually belong to a single fungus, Rhizopogon vinicolor A. H. Smith; cultural characteristics of this fungus are described. Pure culture mycorrhiza syntheses with both mycorrhizal and sporocarpic isolates and Douglas-fir seedlings are reported. Antagonism tests revealed the following inhibition of root pathogens by R. vinicolor: strong—Phytophthora cinnamomi Rands, Pythium debaryanum Heese, and Pythium sylvaticum Campbell & Hendrix; moderate—Fomes annosus (Fr.) Cke. and Poria weirii Murr.; and weak or none— Fusarium oxysporum f. pini (Hartig) Snyd. & Hans., Pythium ultimum Trow, Rhizoctonia solani Kuehn, and Macrophomina phaseoli (Maubl.) Ashby.
The kinetics of pycnospore liberation in Septoria tritici
Authors: Eyal Z.
Published: September 2008

Productivity and rate of liberation of spores from pycnidia of Septoria tritici on green detached flag leaves of field origin and from pycnidia on artificially inoculated wheat seedlings were studied. About 40% of the total spores within a pycnidium were exuded after the initial wetting, but the final percentage of spores which oozed naturally from the pycnidium ranged from 60 to 80% of the total spores, depending on the wheat cultivar and the environmental conditions in which the infected host was grown. The pycnidia were ellipsoid and their volume was calculated for both dried and wet pycnidia. The volume of wet pycnidia varied within the range of 0.012 to 0.019 mm3, which is about a 30% increase over the dry pycnidia, whose volume varied within the range of 0.003 to 0.006 mm3. The correlation between pycnidial volume and total number of pycnospores per pycnidium was non-linear. Wetting and drying treatments had little effect on pycnospore production and liberation rate, and did not cause the production of new pycnidia on detached green leaves.
Properties and inheritance of urease isoenzymes in soybean seeds
Authors: Buttery B. R. , Buzzell R. I.
Published: September 2008

Seeds of soybean (Glycine max (L.) Merrill) cultivars were surveyed for urease isoenzymes. The main isoenzymes were found to be either fast- or slow-running on acrylamide gels (Rp 0.54–0.57 and 0.36–0.41 on 5% gels), and this was a varietal characteristic. Pedigree relationships and segregation in experimental crosses indicated that the isoenzymes were under the control of a single major gene pair, with fast-running dominant over slow-running. The symbols Eu and eu are proposed. The molecular weight of the slow form was about double that of the fast form. The apparent mean energy of activation of crude urease from the dominant fast form (40.5 k J/mol) was less than that of the slow form (47.9 k J/mol). Differences between the homozygous and heterozygous fast types were not detected. The simplest explanation of the results is that the slow-running type is a dimeric form of the fast type, and that the gene is controlling the degree of polymerization of the molecule. Dissociation of the slow type into a smaller unit with a migration ratio similar to that of the natural fast type but a slightly different migration rate suggests, however, that the two types may differ either in molecular conformation or in primary structure.
Folate and polyamine content of undifferentiated and differentiated wheat stem rust uredosporelings
Authors: Kim W. K.
Published: September 2008

Differentiated uredosporelings contained less total folate, less methylated folates, but more formylated folates of low levels of conjugation than did undifferentiated uredosporelings. The extracts contained spermidine and smaller amounts of an unidentified polyamine. The polyamine content increased after germination, especially after formation of infection structures.
Chemotaxonomic investigations on the Dryopteris cristata complex in North America
Authors: Widén C.-J. , Britton D. M.
Published: September 2008

A chromatographic analysis of the phloroglucinol derivatives of 136 collections of D. ludoviciana (Kunze) Small (2x), D. goldiana (Hook.) A. Gray (2x), D. cristata (L.) A. Gray (4x), D. celsa (Palmer) Small (4x), D. clintoniana (D. C. Eaton) Dowell (6x), and six of their hybrids is presented. The phloroglucinol derivatives in these taxa exist as complicated mixtures of butyryl (B), propionyl, (P), and acetyl (A) homologs. Each taxon seems to contain different percentages of homologs. Albaspidin PA (I) and flavaspidic acid AB (IV) have been isolated from Dryopteris for the first time. Cytological results suggest that D. celsa and D. cristata are allotetraploid species derived from D. ludoviciana and D. goldiana; and D. ludoviciana and an unknown diploid, respectively; whereas D. clintoniana is an allohexaploid derived from D. goldiana and D. cristata. The chromatographic results support these interpretations. Phloroglucinol compounds that are found in the parent species also occur in their interspecific hybrids.
Chemosystematic studies in the genus Pinus: the leaf oil of Pinus contorta var. latifolia
Authors: Pauly G. , Rudloff E. von
Published: September 2008

Gas chromatographic analysis of the volatile oil of the leaf oil of lodgepole pine from the Rocky Mountains showed 1-β-phellandrene (34%) and 1-β-pinene (30.5%) as major components. Lesser amounts of α-pinene (6.5%), myrcene (3%), cis-ocimene (2.5%), 3-carene (1.5%), terpinolene (1%), γ-terpinene (0.3%), α-terpineol (4%), terpinen-4-ol (0.5%), estragole (0.5%), bornyl acetate (0.5%), linalool (0.3%), a mixture of cadinene isomers (5%), cadinol and muurolol isomers (1.5%), nerolidol (0.6%), and tentatively identified camphene, α-phellandrene, limonene, isopulegol, camphene hydrate, citronellol, bisabolol, and cis- and trans-farnesol were recorded. In addition, hex-2-en-1-al (1.5%) and cis-hex-3-en-1-ol (1%) were isolated, but these may be artefacts because the leaves had to be cut to obtain a high yield of oil. The variation in the relative amounts of terpenes in leaves at different heights on a tree was small. Quantitative analysis of 10 samples per population showed a relatively high tree-to-tree variation, but similar mean values for populations in the Bragg Creek – Kananaskis – Eisenhower Junction area of Alberta. Small, but possibly significant differences were recorded for the samples from the Cypress Hills. Populations north of Lake Louise Station to Jasper, Hinton, and Edson were found to contain a few individuals with terpenes characteristic of jack pine. This indicates that the effects of introgression of lodgepole and jack pine can be detected further southwest than previously reported.
The systematics of Clarkia, section Myxocarpa
Authors: Small Ernest
Published: September 2008

Two previously described diploid species in Clarkia, section Myxocarpa, have been found to comprise five allopatric groups, which are reproductively isolated by very strong chromosomal sterility barriers, and are divergent ecologically. Two of these groups are each made up of a pair of distinctive races. All of these are extremely difficult to distinguish morphologically, although consistent differences have been found. Emphasizing reproductive, ecological, and distributional criteria, these have been recognized as five species, two of which are composed of a pair of subspecies. The relationships of the proposed taxa to the other two species of section Myxocarpa are examined, and the problem of treating the group taxonomically is considered.
Photosynthesis and CO2 evolution by leaf discs: gas exchange, extraction, and ion-exchange fractionation of 14C-labeled photosynthetic products
Authors: Atkins C. A. , Canvin D. T.
Published: September 2008

A leaf chamber is described which allows the measurement of the gas exchange of leaf discs in an open gas analysis system. Pretreatment of the leaf discs with nitrogen and inclusion of moist filter paper in the leaf chamber resulted in rates of photosynthesis that were constant for 40 min and equal to 60 to 70% of the rate of photosynthesis measured in intact leaves. Analysis of the products of 14CO2 fixation from whole leaves and leaf discs and a comparison of the gas exchange under various conditions established that the leaf discs accurately reflected the metabolism of the attached leaves.
Preservation of suspension cultures of plant cells by freezing
Authors: Latta R.
Published: September 2008

Development of a method of preserving suspension cultures of plant cells has been undertaken. When grown in a conventional medium containing 20 g/1 of sucrose, Daucus carota cells survived freezing and a short period of storage at −40 °C or −196 °C in the presence of a suitable protective agent, whereas Ipomoea sp. cells did not. Ipomoea cells survived freezing if they were adapted to growth in a medium containing 65 g/1 of sucrose.
A simplified method for isolating bacteria-free crown gall tissue from Vinca rosea
Authors: Manasse Robert J. , Lipetz Jacques
Published: September 2008

A simplified procedure for the isolation of bacteria-free crown gall tissues requiring only a temperature-controlled water bath is described. Agrobacterium tumefaciens recovered from stem sections during this procedure retain their tumor-inducing properties as well as their antibiotic resistance.
Scanning electron microscopy of basidiospores of species of Strobilomycetaceae
Authors: Grand Larry F. , Moore Royall T.
Published: September 2008

Basidiospores of 13 North American species of Strobilomycetaceae were examined by scanning electron microscopy. Similarities and differences of surface features among species are discussed in relation to their possible role in the taxonomy of the family.
Pollen development in Douglas fir (Pseudotsuga menziesii)
Authors: Owens John N. , Molder Marje
Published: September 2008

The normal sequence of pollen development in Douglas fir is described and is essentially the same as that for Pinus. Mature pollen grains normally consist of five cells: two lens-shaped prothallial cells, a stalk cell, a body cell, and a large tube cell. The normal sequence of development is described as well as the structure and histochemistry of the spore wall. Possible reasons are given for earlier misinterpretations of pollen development and spore wall structure in Douglas fir.
Ascocarp development in Rhytisma acerinum and R. punctatum
Authors: Duravetz J. S. , Morgan-Jones J. F.
Published: September 2008

In Rhytisma acerinum, the apothecial primordium differentiates simultaneously into three layers: (1) roof, (2) hypothecium, and (3) basal stroma. By contrast, the primordium of R. punctatum differentiates initially into two layers, the upper one becoming the roof, the lower then differentiating further into hypothecium and stroma. Asci and paraphyses of both species originate in the hypothecium. In R. punctatum, uni- or bi-nucleate ascogenous initials occur near the bases of the paraphyses, binucleate initials apparently resulting when two uninucleate elements fuse. A binucleate initial may then (1) develop into a single ascus, (2) elongate slightly and produce several outgrowths which become asci, or (3) develop into a septate or aseptate ascogenous hypha bearing a number of asci. These three developmental patterns also occur in R. acerinum though ascocarps of this species were too mature to show unproliferated initials. Conjugate division in proliferating ascogenous elements is inferred from the frequent occurrence of nuclei in closely associated quartets or pairs. The systematic position of Rhytisma is evaluated and it is proposed that the genus be removed from the Hypodermataceae Rehm sensu von Arx and Müller and placed in the Rhytismataceae Chev.
Ultrastructure of Scenedesmus strain 614 bristles
Authors: Trainor Francis R. , Massalski Andrzej
Published: September 2008

Numerous bristles were detected on colonies of Scenedesmus strain 614 when examined with the electron microscope. These appendages may be 200 μ long, occur in groups, and originate from openings in the outer layer. Bristles are composed of longitudinal microstrands, with an organized crossbanding. There is some discussion concerning bristle function, as well as reasons why others have failed to observe them in previous ultrastructural studies with strain 614.
Inoculation of rooted basswood cuttings with ectomycorrhizal fungi
Authors: Park J. Y.
Published: September 2008

Because seeds of American basswood, Tilia americana L., exhibit a pronounced dormancy, and germinate irregularly (often only after 1 or more years of incubation), it is difficult to obtain aseptic seedlings for mycorrhizal studies. Techniques were developed to inoculate rooted cuttings with ectomycorrhizal fungi, Cenococcum graniforme (Sow.) Ferd. & Winge, and Lactarius sp. After 6 months, mycorrhizal inoculation was successful. The results indicate that this technique will produce adequate experimental material of this hard-seed species to permit studies of mycorrhizal relationships.
On conidia of fungi, and gemmae of algae, bryophytes, and pteridophytes
Authors: Hughes S. J.
Published: September 2008

The methods of gemma production found in algae, bryophytes, and pteridophytes are considered in the light of those methods of conidium formation distinguished in fungi. Most gemmae are exogenous, but endogenous gemmae occur in a few Hepaticae. Solitary, blastic, sessile, or stalked gemmae, not accompanied by proliferation of the gemmifer, are found in the three groups of cryptogams. Gemmae produced from acropetally formed chains of initials are found in Hepaticae and Musci, and those from basipetally delimited chains of initials are found in Hepaticae only. In Hepaticae the gemmifers do not proliferate or extend, but in other groups solitary terminal gemmae can be formed on successive proliferations or extensions of the gemmifers. Thus, gemmae can arise on lateral, subterminal proliferations of the gemmifer in Musci and Filicales, and on percurrent proliferations of the gemmifer in algae and Musci. Also in Musci the gemmifer may bear a distal meristematic cell which cuts off a basipetal succession of gemmae. It is noted that Hepaticae, Musci, and Anthocerotae differ significantly in their respective methods of gemma production.The various kinds of proliferation of conidiogenous cells in fungi and of gemmifers in other cryptogams, and the feature of acropetal and basipetal delimitation of diaspore initials are discussed. A key to kinds of gemma production is presented.
An influence of water regime on the light response in germination of lettuce (Lactuca sativa var. Grand Rapids) seed
Authors: Hsiao A. I-hsiung , Simpson G. M.
Published: September 2008

The germination response of Lactuca sativa L. var. Grand Rapids to different light qualities (red, blue, far-red, white) compared with darkness, is modified by the level of water in the petri plate used for germinating the seeds. Far-red light and blue light inhibit germination for 24 h in all levels of water studied whereas red inhibits in low levels and promotes in high levels. White light inhibits germination in low levels of water but not in high levels. At least part of the inhibiting effects of light on germination in low levels of water may be associated with induced lowering of water potential in the seeds.
Thallus growth and the distribution of stored metabolites in the phycobionts of the lichens Parmelia sulcata and P. physodes
Authors: Harris G. P. , Kershaw K. A.
Published: September 2008

The growth of two lichens, Parmelia sulcata and P. physodes, has been examined under controlled conditions. It has been shown that continuous light leads to early death of both lichens. Evidence from fine structure work following pretreatment of the lichen thallus with different levels of thallus saturation indicates that fluctuating wet and dry conditions are also vitally necessary for continued thallus growth. This is explicable in terms of the relative mobility of fixed carbon from the algal component at different levels of thallus saturation.
Hormonal control of the respiratory climacteric in Sauromatum guttatum (Araceae)
Authors: Buggeln Richard G. , Meeuse Bastiaan J. D.
Published: September 2008

A respiratory climacteric (RC) occurs in the appendix (terminal portion of the spadix) of the inflorescence of Sauromatum guttatum Schott during blooming. We have devised purification techniques and a bioassay for calorigen, the compound (synthesized in the staminate flower buds) which triggers the RC in the Sauromatum appendix.Inflorescences were induced to bloom under controlled conditions to determine (1) the time required for calorigen to be released from the staminate flowers and to accumulate in the appendix, and (2) the time required for calorigen to trigger the RC in the appendix. The latter results were confirmed by the direct addition of calorigen to appendix sections in a bioassay.A calorigen-like substance was extracted from the staminate flowers of Arum maculatum, A. italicum, A. dioscoridis, and Dracunculus vulgaris.
Biosystematic studies in the North American species of Linum, section Adenolinum (Linaceae)
Authors: Mosquin Theodore
Published: September 2008

Variation patterns and interpopulational relationships were examined in Linum lewisii Pursh and L. pratense (Norton) Small, the two native North American blue-flowered flax species. The two principal evolutionary trends in the North American populations have been toward self-pollination and an annual life habit. A third trend, toward greater outcrossing, is considered probable. Hybridizations between and within species indicate that evolution has occurred mainly by the accumulation of small genic changes in geographically isolated populations. The buildup of sterility barriers between populations regardless of species has not been extensive and in no case do hybrids have less than 30% good pollen. In general, morphological evolution has occurred independently of the buildup of sterility barriers. A new taxonomic combination, L. lewisii ssp. lepagei (Boivin) Mosquin, is adopted.
Studies on lichen-dominated systems. II. The growth pattern of Cladonia alpestris and Cladonia rangiferina
Authors: Kershaw K. A. , Rouse W. R.
Published: September 2008

Random samples of Cladonia alpestris show a strong correlation of podetial length, podetial diameter, and internode length, with soil moisture. The level of soil moisture is effectively an integration of net radiation and thus also reflects drying rates of the lichen canopy and the relative metabolic activity of the lichen. The existence of a large-scale mosaic pattern of 'drying rates' is demonstrated by traditional pattern analysis. The interactions of all pattern scales in Cladonia alpestris, C. rangiferina, Ledum groenlandicum, and lichen depth are examined by covariance analysis and interpreted in terms of water relations of the lichen. Experimental evidence is presented of the relative magnitude of evaporation gradients in open and closed spruce–lichen woodland.
Histological studies on embryos produced from cell cultures of Bromus inermis
Authors: Constabel F. , Miller R. A. , Gamborg O. L.
Published: September 2008

A histological study has been made of the embryos produced in a brome cell suspension culture. In 2,4-dichlorophenoxyacetic acid-free defined medium, several types of cell aggregates were produced. Some of the aggregates were proembryo-like structures. A frequent intermediate in embryogenesis was a "tadpole"-like structure. Shoot and root primordia were produced within the proembryonic structures. Plant development proceeded by the formation of a shoot–root axis, then roots developed and later the coleoptile and leaves were produced.
The effect of some environmental factors on the growth of young aspen trees (Populus tremuloides) in controlled environments
Authors: Bate G. C. , Canvin D. T.
Published: September 2008

Several populations (each of 32 trees) of young aspen trees (Populus tremuloides Michx) were allowed to break from dormancy in controlled environment cabinets. The rate of photosynthesis and dark respiration and the rate of carbon gain (as difference between photosynthesis and respiration) of the population as affected by photoperiod duration, light intensity, and day/night temperatures was determined by measuring the CO2 exchange of the whole population using the controlled environment cabinet as the plant chamber.The rates of photosynthesis of the plants were similar during both 12- or 18-h photoperiods. The rates of respiration during the corresponding night periods were also similar. In continuous light the photosynthetic rate remained unchanged if growth (expansion of new leaves) was rapid. During periods of slower growth, the photosynthetic rate in continuous light was reduced. In spite of this reduction in the rate of photosynthesis, carbon gain was still greatest under continuous light.In the day/night temperature study, the largest gains in carbon per day by the aspen trees were obtained at day/night temperatures of 15/10 °C or 15/15 °C. Higher day or night temperatures resulted in decreased rates of carbon gain.Increased light intensity from fluorescent lamps resulted in increased rates of photosynthesis. Addition of incandescent light to the fluorescent light resulted, in almost all cases, in decreased rates of photosynthesis. This may, in part, be due to effects on leaf temperature.Photosynthesis of the populations was usually maximal at the beginning of the photoperiod and decreased steadily during the photoperiod. The rate of decrease was directly related to the rate of photosynthesis at the beginning of the photoperiod.Both photosynthesis and respiration were affected by temperature and light but no clear relationship existed between the rate of CO2 exchange during the photoperiod and that during the nyctoperiod following.
Cytotaxonomic studies of Draba species of Canada and Alaska: D. ventosa, D. ruaxes, and D. paysonii
Authors: Mulligan Gerald A.
Published: September 2008

The cytotaxonomy of three closely related species of Draba, of the mountains of western North America, is discussed and a key is given: D. ventosa A. Gray (2n = 36), D. ruaxes Payson & St. John (2n = ca. 72), and D. paysonii Macbride (2n = 42). Evidence is presented demonstrating that D. ventosa and D. paysonii are triploids reproducing by agamospermy whereas the hexaploid species D. ruaxes is a sexual outcrosser. The former two species produce seed apomictically without any pollen stimulation. Draba ventosa and D. ruaxes have the basic chromosome number x = 12 and D. paysonii has the base number x = 14.
Environmental control of gametogenesis in Laminaria saccharina. I. The effects of light and culture media
Authors: Hsiao Stephen I. C. , Druehl Louis D.
Published: September 2008

Gametogenesis of Laminaria saccharina (L.) Lamouroux has been investigated in unialgal culture using both defined media and natural seawater with various light intensities and photoperiods at 10C. The optimal conditions for gametogenesis were 18-h photoperiod, 860 lx, and ASP 2 M culture medium. Generally the more profusely branched plants were produced under conditions most favorable to gamete production; the percentage of fertile male gametophytes was appreciably greater than that of female gametophytes; and antheridia were produced before oogonia.
Lateral sieve-area pores in woody dicotyledons
Authors: Evert R. F. , Deshpande B. P. , Eichhorn S. E.
Published: September 2008

The secondary phloem of seven species of woody dicotyledons (Populus deltoides, Quercus alba, Rhus glabra, Robinia pseudoacacia, Salix nigra, Tilia americana, and Ulmus americana) was fixed in glutaraldehyde and in formaldehyde–glutaraldehyde and postfixed in osmium tetroxide for electron microscopy. The pores of the lateral sieve areas are essentially similar in structure to those of the sieve plates, with the exception that many of the lateral sieve-area pores contain median nodules at maturity. In addition, some pore groups in Rhus, Robinia, and Tilia are associated with median cavities, median enlargements arising through the union of two or more median nodules, similar to those associated with the sieve areas of conifers. The lateral sieve-area pores are lined by the plasmalemma and variable amounts of callose and contain P-protein. It has been concluded that the P-protein normally is loosely arranged in the pores.
Carbon dioxide uptake by succulents
Authors: Holdsworth M.
Published: September 2008

Carbon dioxide absorption by a selection of succulent plants, was followed by a modification of Tregunna's method, in which the plant sample on absorbing the carbon dioxide from an enclosed volume of air in contact with weak bicarbonate, causes the solution's pH to change. Of the 21 species tested, 11 took up carbon dioxide in the dark: Lithops turbiniformis, Zygocactus truncatus, Bryophyllum daigremontianum, Crassula multicava, Echeveria gibbiflora, Kalanchoe blossfeldiana, Sedum confusum, S. pachyphyllum, S. rubrotinctum, S. spectabile, Aloe globuligemma. The duration of uptake varied from a few hours to the whole night (and longer). Even in those other species where uptake occurred in the daytime it started and stopped at times not immediately related to the onset of light or darkness.
Initiation of DNA synthesis by kinetin and experimental factors in tobacco pith tissues in vitro
Authors: Simard Antoine
Published: September 2008

Since previous investigations had suggested that kinetin, like auxin, may initiate DNA synthesis in tobacco pith cells, a study was undertaken to learn whether the observed incorporation of tritiated thymidine into nuclear DNA in the presence of kinetin could be explained by different experimental factors.Pith tissues were isolated and allowed to rest a few days after excision and they were then placed on White's basic medium or on that medium supplemented with either one or both of the growth regulators in the presence of tritiated thymidine.The results of those studies, obtained by radioautographic and liquid scintillation counting methods, showed no statistically significant differences between pith tissues kept on the control medium and those on kinetin-containing medium. Similar tissues placed on an auxin or auxin- and kinetin-containing medium showed, as expected, a significant incorporation of tritiated thymidine into the DNA of pith cell nuclei.