bluuebunny/crossref_metadata_2025_split huggingface dataset:
A TEMPORARY SECTION THROUGH LATE‐DEVENSIAN SEDIMENTS AT GREEN LANE, DALTON‐IN‐FURNESS, LANCASHIRE
Authors: JOHNSON R. H. , TALLIS J. H. , PEARSON M. 
Published: May 2006

SummaryThe glacial geomorphology of the Furness region is described in relation to the sequence of events during the Last (Devensian) Glaciation. Towards the close of this period melt‐streams formed parallel to the upland margins of the wasting ice‐sheets, and a complex network of melt‐water channels was eroded on the lower hill‐slopes. In one such channel at Dalton‐in‐Furness two organic layers interbedded in clay were temporarily exposed during building operations in 1970. Pollen analysis revealed a sequence of Late‐Devensian (Late‐glacial) deposits, interrupted near the top by a layer of soliflucted grey clay. Seven sub‐zones, covering Zones I to early Zone IV are recognized, based on differing representations of seven major pollen assemblages. The affinities of the pollen diagram to other published Lake District diagrams are discussed.
ORGANIC FLUORINE IN TROPICAL SOILS
Authors: HALL R. J. , CAIN R. B. 
Published: May 2006

SummaryA number of tropical soils growing toxic plant species which contain organically combined fluorine have been studied with a view to establishing the relationship between plant and soil in terms of fluorine. The analyses of the soils for total fluorine and water‐soluble fluoride showed that there was no correlation with the levels of total and organically‐combined fluorine in the leaves of the plant species. Some of the most toxic plants grew in soils having low levels of mineral fluorine. Examination by electrodialysis, gas‐liquid chromatography and infra‐red spectroscopy, supported by chemical analysis, has revealed the presence in significant amounts of what appears to be fluoroacetate in several of the soils supporting species known to contain toxic fluorinated fatty acids. The origin of the naturally‐occurring fluoroacetate in these soils is discussed.
ION ABSORPTION BY ROOTS: THE ROLE OF MICRO‐ORGANISMS
Authors: EPSTEIN EMANUEL 
Published: May 2006

SummaryTheoretical considerations and experimental evidence are adduced to the effect that ion absorption by plant tissue from solutions in the range of low concentrations (< 1 mM) is due to the type 1 mechanisms of ion transport of the plant cell membranes, not to bacteria associated with the tissue.
VARIABILITY IN THE WILD RASPBERRY
Authors: KEEP ELIZABETH 
Published: May 2006

SummarySurveys of wild raspberries in Europe and Britain, and of progenies raised from seed collected in the wild, showed widespread polymorphism for the gene H (hairy/subglabrous canes) and less frequent polymorphism for P (spine colour intensifier). No yellow fruited (t), spineless (s) or sepaloid (sx3) plants were seen. Breeding experiments snowed there was no close linkage between H and the incompatibility S locus. Male sterility occurred in three out of nineteen progenies and partial female sterility, accompanied by abnormalities affecting vegetative characters, segregated in three out of eleven progenies from sibbing four seedlings. This condition was due to a semi‐lethal gene, gr.Progenies varied widely in response to powdery mildew (Sphaerotheca macularis (Fr.) Jaczewski), from 0 to 100% of seedlings proving resistant. The incidence of resistance in progenies tended to increase with increasing altitudinal origin of the parent, total percentage resistance in all progenies being 6.6, 59.6, 64.3 and 97.2 for parental altitudes of less than 500 m, 500–1000 m, 1000–1500 m and over 1500 m, respectively. It is suggested that higher mildew resistance may be a secondary effect of greater cold hardiness at high altitudes.Resistance to the aphid Amphorophora rubi occurred in seventeen out of twenty‐eight wild progenies. Resistance to strain 3 of the aphid was more common than to strain 2; in both cases, the incidence of resistance tended to decrease with increasing altitude of the parent. Only one very small progeny was homozygous for resistance. Resistant and susceptible classes were usually sharply differentiated, indicating the segregation of major resistance genes. Genes conferring, respectively, strain 2 resistance alone, strain 3 resistance alone and resistance to both strains, were isolated.
THE INTERACTION BETWEEN GROWTH PROMOTERS IN APICAL DOMINANCE
Authors: WOOLLEY D. J. , WAREING P. F. 
Published: May 2006

SummaryThe effects of light intensity, day length and nitrogen status on lateral bud growth and endogenous levels of gibberellins and cytokinins were investigated. Low light intensity had little effect on gibberellin levels in the leaves of long–day plants but greatly increased acidic gibberellin levels in short‐day leaves. Both short days and low nitrogen status reduced cytokinin levels in the roots. The correlation between lateral shoot development and endogenous cytokinin levels was consistent with results obtained using exogenous hormones: this correlation strongly suggests that lateral shoot development is controlled by a delicate balance between auxins, gibberellins and root–produced cytokinins.
THE PHASE‐RESPONSE OF THE DARK STOMATAL RHYTHM IN TRADESCANTIA VIRGINIANA TO LIGHT AND DARK TREATMENTS
Authors: MARTIN E. S. , MEIDNER H. 
Published: May 2006

SummaryIn continued darkness following a standard pretreatment of 12 hours light and 12 hours dark, the stomata of Tradescantia virginiana did not reveal a truly repeating rhythm, but only a single opening cycle which matched the opening phase of the rhythm in light. An investigation of the phase response of this dark opening cycle to light and dark treatments revealed that the phase of the dark opening cycle could be manipulated as follows. When light commenced during that phase characteristic of darkness in nature, the dark opening cycle showed phase‐shift, but little or no phase‐shift occurred when light commenced during that phase characteristic of light in nature. The fact that the rhythms can be manipulated in this manner may indicate the plant's ability to adapt to different day lengths.
THE DISTRIBUTION AND ROLE OF CYTOPLASMIC MEMBRANE‐BOUNDED VESICLES DURING THE DEVELOPMENT OF BOTRYOSE SOLITARY BLASTOSPORES OF TWO FUNGI
Authors: COOK BERYL E. 
Published: May 2006

SummaryDuring a study of the fine structure of developing conidiophores and spores of Oedocephalum roseum it was found that two kinds of wall growth existed: (a) growth and extension involving addition of wall material, i.e. wall synthesis; (b) extension only, i.e. growth without synthesis but involving instead plasticizing of the wall. The latter type of growth occurred only during denticle formation. Associated with these two types of growth were two different kinds of cytoplasmic organization. During growth involving extension and synthesis, membrane‐bounded vesicles of two different sizes were present, but during growth involving extension alone, only the smaller vesicles were present. Observations of Fomes annosus showed a similar pattern. The implications of the observations are discussed.
CORRELATED LIGHT AND ELECTRON MICROSCOPE STUDIES ON BROWN ALGAE I. LOCALIZATION OF ALGINIC ACID AND SULPHATED POLYSACCHARIDES IN DICTYOTA
Authors: EVANS L. V. , HOLLIGAN M. SUSAN 
Published: May 2006

SummaryBy electron microscopy and light microscope histochemical techniques, alginic acid and sulphated polysaccharides (probably largely fucoidan) have been located in the cell walls of Dictyota dichotoma.The cell walls of the vegetative thallus and those of mature reproductive cells (tetrasporangia, tetraspores, antheridia and oogonia) are composed of three to four well‐defined layers, mainly of alginic acid, sulphated polysaccharide or a mixture of these substances. Prior to their secretion the two types of polysaccharide can generally be detected in conspicuous, peripheral, intra‐cellular cytoplasmic vesicles. Alginic acid is liberated from vesicles through the plasma membrane by reversed pinocytosis.The results are discussed in relation to other work on the polysaccharides and histochemistry of brown algae.
CORRELATED LIGHT AND ELECTRON MICROSCOPE STUDIES ON BROWN ALGAE
Authors: EVANS L. V. , HOLLIGAN M. SUSAN 
Published: May 2006

SummaryThe physodes or fucosan vesicles abundant in vegetative and reproductive cells of the brown seaweed Dictyota originate in the plastids. Precursor material expelled from the chloroplast matrix, may run together to produce the large physodes in the cell cytoplasm. Staining reactions indicate that the physodes are phenolic or tannin‐like in nature. They may be products of photosynthesis. Physodes in the apical region of thalli are exceedingly resistant and stable compared with those in older parts of thalli; the latter are lost during glutaraldehyde fixation.
BREEDING SYSTEMS IN COTULA L. (COMPOSITAE, ANTHEMIDEAE) II. MONOECIOUS POPULATIONS
Authors: LLOYD DAVID G. 
Published: May 2006

SummaryThe distribution of male and female florets in heads of monoecious populations is represented by a curve joining points on a graph of percentage of female florets against rank in the same percentage. Comparison of curves for samples from different origins in Cotula minor and C. atrata subsp. atrata shows that sex expression is not greatly influenced by macro‐environmental differences. Much of the total intra‐population variation in sex expression appears in the heads collected at one time from a single plant. The rank‐frequency curves show marked differences between species in the percentages of male and female florets. The average percentage of female florets in seventeen monoecious species is negatively correlated with the floret length, a measure of adaptation to outbreeding. In three species, the seed set and subsequent germination percentages are slightly lower after self‐pollination than after cross‐pollination. Self‐fertilization probably occurs in varying degrees in the monoecious species. Monoecy has arisen independently in sections Leptinella and Strongylosperma.
A DATA BANK OF QUATERNARY PLANT FOSSIL RECORDS
Authors: DEACON JOY 
Published: May 2006

SummaryA data bank of British Quaternary plant fossil records has been established in the Subdepartment of Quaternary Research, Cambridge. The bank is based on an exhaustive survey of the literature and includes both fossil pollen and macrofossil records. The information entered on each record card includes, whenever possible: grid reference of site; zone, stage and radiocarbon date of sediment; average frequency of pollen type; details of stratigraphy and archaeological correlations. Examples of how the bank can be used are given.
LATE‐GLACIAL DEPOSITS NEAR CAPEL CURIG, CAERNARVONSHIRE
Authors: CRABTREE K. 
Published: May 2006

SummaryInvestigations into former lake basins in the region to the north of Capel Curig (SH 721581) in Caernarvonshire have revealed deposits of Late‐glacial age. Pollen analysis of the deposits permits subdivision of the sequence into the standard Late‐glacial zones I, II and III together with some sub‐zones based upon recurring pollen assemblages. Some of the ecological implications of these assemblages are discussed, in terms of vegetation, climate and soils. High Rumex* pollen values characterize pollen zone I. A wide range of herbs and Betula pollen dominate in zone II. Zone III is characterized by high Artemisia pollen values. A transition zone III–IV is included to cover the Empetrum and Juniperus pollen peaks, prior to the rapid rise in Betula pollen values in zone IV.
THE CELLULAR LOCATION OF LEAD AND POTASSIUM IN THE LICHEN CLADONIA RANGIFORMIS (L.) HOFFM.
Authors: BROWN D. H. , SLINGSBY D. R. 
Published: May 2006

SummaryThe cellular location of lead and potassium has been studied in the lichen Cladonia rangiformis, collected from a lead‐rich site. Elution of ions by dilute acid or their replacement by other ions has demonstrated that lead is ionically bound, most probably within the cell wall. The same techniques have shown a proportion of the total potassium to be also bound ionically in the cell wall. In addition potassium is present as freely diffusible material retained within the permeability barriers of the intact cell and also firmly bound in an insoluble form. The reported tolerance of lichens to heavy metals is discussed in relation to the demonstrated location of lead.
IDENTIFICATION OF FOSSIL SEEDS OF ERICA AND CALLUNA BY SCANNING ELECTRON MICROSCOPY
Authors: HUCKERBY E. , MARCHANT R. , OLDFIELD F. 
Published: May 2006

SummaryA study of the surfaces of Erica and Calluna seeds by S.E.M. reveals a range of morphological characteristics, which can be used in conjunction with features more readily visible by conventional light microscopy to separate contemporary reference material of all the West European species. These fine morphological characteristics have also been detected on well‐preserved Pleistocene material from south‐west France and used to identify eight separate Erica species in the fossil record. Where the surface of fossil seeds has been sufficiently degraded an underlying regularly pitted layer is revealed which seems to be present in all the species recorded and has frequently been observed and used in identification by previous workers using transmitted light microscopy.
A METHOD FOR DETERMINING ABSOLUTE POLLEN FREQUENCIES IN LAKE SEDIMENTS
Authors: BONNY ANNE P. 
Published: May 2006

SummaryA detailed account is given of the procedure required to obtain an estimate of fossil pollen per unit volume of sediment, using a method, outlined by previous workers, which involves the addition of a known number of exotic or ‘marker’ pollen grains. Sources of error in the method are discussed and statistical tests for certain errors are included. Details are given of calculations whereby confidence limits are obtained for the counting error of fossil pollen concentration. Absolute pollen counts obtained by means of this method from a Late‐Weichselian profile of lake sediments provide additional information for the expenditure of little extra time.
A SIMPLE INTEGRATING PHOTOMETER
Authors: DREW EDWARD A. 
Published: May 2006

SummaryA selenium photovoltaic cell coupled to a mercury electrolytic coulometer makes a useful integrating photometer with the following features: linear response to a wide range of intensities; high sensitivity from 400 to 650 nm; cosine light collection; no power requirements, minimum circuitry; robust, resistant to all environmental conditions; small size, easy construction and low cost. Results from use underwater show good correlation with expected light attenuation and readings can easily be converted to absolute light energy units.
THE MOVEMENT OF CARBOHYDRATE FROM THE ALGA TO THE FUNGUS IN THE LICHEN PELTIGERA POLYDACTYLA
Authors: HILL D. J. 
Published: May 2006

SummaryThe pattern of incorporation of 14C into the thallus during incubation with H14CO3‐ in the light suggested that a substance in the 80% ethanol insoluble fraction, an unknown compound (probably a sugar phosphate) and glucose were intermediates in the transfer of carbon to the fungus. Results are presented which are consistent with the hypothesis that the alga releases a glucan which the fungus hydrolyses extra cellularly to form glucose. This glucose is then taken up by the fungus and converted to mannitol.
A RELATIONSHIP BETWEEN OXYGEN TRANSPORT AND THE FORMATION OF THE ECTOTROPHIC MYCORRHIZAL SHEATH IN CONIFER SEEDLINGS
Authors: READ D. J. , ARMSTRONG W. 
Published: May 2006

SummaryThe response of the mycorrhizal fungus, Boletus variegatus, to living coniferous roots and to hollow silicone rubber ‘roots’ in anaerobic media was investigated. Mycelial macerates were cultured in nutrient and non‐nutrient agar media in tubes. The roots of whole seedlings or silicone ‘roots’ were placed in the media to a depth of several centimeters below the air‐agar interface. The silicone ‘roots’ were either provided with access to the atmosphere by means of a capillary tube exposed above the agar surface, or were sealed.In young seedlings with unsuberized roots a diffuse fungal growth occurred over the whole root surface. In older, suberized, root systems, colonization was restricted to areas of the main axis through which short laterals were appearing. It was demonstrated polarographically that the area stimulating fungal growth were the only areas of significant oxygen evolution along the root. Fungal growth occurred around the silicone ‘roots’ only when access to air was provided by the capillary. It took the form of a diffuse mycelial ball in non‐nutrient medium but, in mitrient agar, of a tight sheath with a distinct tendency for pseudoparenchyma formation. The possible role of oxygen evolution from roots is discussed both in terms of the initial stimulus to the symbiont and of the continued physiological activity of the mycorrhiza.
ROOTING OF HARDWOOD CUTTINGS IN RELATION TO BUD DORMANCY AND THE AUXIN CONTENT OF THE EXCISED STEMS
Authors: SMITH N. G. , WAREING P. F. 
Published: May 2006

SummaryExperimental evidence is given for poplar cuttings (Populus x robusta Schneid.) of the role of dormant and nondormant buds to root initiation. Chilling treatments shortened bud dormancy and greatly increased the emergence of pre‐formed roots from stem cuttings, but caused a smaller increase in numbers of wound‐roots. With terminal popular cuttings greater root numbers were obtained when, after excision, a warm treatment preceded chilling. Chilling only induced a large increase in the number of wound‐roots on terminal apple cuttings (Malus cv. Mailing II), if steeped in indolyl butyric acid immediately after the chilling treatment.A greater amount of auxin was found in chilled than in unchilled poplar cuttings five weeks after the end of chilling.Endogenous auxin levels at the base of both intact and disbudded, chilled cuttings of poplar were high at the time when roots were about to emerge from the cortex, but were low 15 days later when the roots were several centimetres in length.
RNA‐DNA HYBRIDIZATION COMPETITION STUDIES ON SENESCING BARLEY LEAVES
Authors: SRIVASTAVA B. I. SAHAI 
Published: May 2006

SummaryNo detectable differences in RNA populations from 7‐day‐old (young) and 17‐day‐old (senescent) first seedling leaves of barley were found by RNA‐DNA hybridization competition experiments. It is suggested that enzymatic changes during senescence may result from minor changes at the transcription level or alterations at the translation level.
MEASUREMENT OF THE TRANS‐ROOT ELECTRICAL POTENTIAL OF PLANTS GROWN IN SOIL
Authors: ANSARI A. Q. , BOWLING D. J. F. 
Published: May 2006

SummaryElectrical potential differences between the soil and the exuding xylem sap of detopped sunflower plants grown in potting compost were measured. The concentrations of some of the major nutrient ions in the soil water and in the xylem sap were determined, enabling the driving forces on the ions to be calculated. The anions, Cl, NO3 and SO4, appeared to be moving from the soil into the sap against the electrochemical potential gradient indicating active transport. There was also evidence that K and Na were actively transported into the xylem. These results are discussed in relation to those obtained with plants grown in water culture. They suggest that this could be a useful method for studying salt uptake by plants growing in the field.
EFFICIENCY TESTS ON THE TAUBER TRAP USED AS A POLLEN SAMPLER IN TURBULENT WATER FLOW
Authors: PECK R. M. 
Published: May 2006

SummaryThe Tauber trap was subjected to tests in the controlled water flow of a flume to assess its sampling efficiency for a range of pollen types and varying speeds of flow. The equipment and procedures of pollen preparation are described, and the method of trap efficiency calculation is explained, Results indicating numerical differences in amounts of pollen caught by two sizes of trap are attributed to scaling factors on the traps used, and the increased flow velocity near the floor of the flume. Similar pollen proportions from these traps in each experiment are obtained, indicating an even distribution of pollen within the flow. Collection efficiency for individual taxa are found to vary both according to size and weight of the grains and the velocity of flow. Within one experiment, other factors being constant, smaller grains arc trapped less efficiently than those larger. The total experimental evidence suggests that, with increasing water speed, differences in grain characteristics have Jess effect, though the overall trapping efficiency is lowered. Factors of weight rather than density are proposed as determining the final catch from water by this particular design of trap. The significance of under‐ and over‐representation of grains at low flow velocities is discussed in relation to the potential use of the trap as a pollen sampling mechanism in the field.
TISSUE CULTURE OF ORCHIDS I. METHODS FOR LEAF TIPS
Authors: CHURCHILL M.‐E. , BALL E. A. , ARDITTI J. 
Published: May 2006

SummaryLeaf‐tips of Epidendrum and Laeliocattleya (Orchidaceae) have been cultured in vitro. Epidendrum seedling leaf‐tips form calli on Murashige‐Skoog medium (MS) or after being transferred to Knudson C agar following prior growth on MS. Plantlets also develop from tips of young leaves of mature Laeliocattleya plants cultured in Heller's medium or in a solution specifically devised for orchid shoot‐tip cultures. In Heller's medium plantlet development is preceded by callus formation whereas in the shoot‐tip medium protocorm‐like bodies are formed first. These tissues when subcultured from Heller's medium or the shoot‐tip solution to Knudson C agar also produce plantlets which resemble orchid seedlings. The results are discussed in relation to the components of each medium, the requirements of germinating orchid seeds and protocorms, and the difficulties encountered in attempts to culture tissues of mono‐cotyledonous plants.
PHOTOSYNTHETIC INDUCTION PHENOMENA AND THE LIGHT ACTIVATION OF RIBULOSE DIPHOSPHATE CARBOXYLASE
Authors: WALKER D. A. 
Published: May 2006

SUMMARYPhotosynthesis often reaches its maximal rate only after an initial induction period of some minutes. Simple induction phenomena in whole plants and intact chloroplasts have common features which imply that they are brought about by the same mechanism. The Osterhout–Haas Hypothesis explains induction in terms of light activation of a catalyst and building up of intermediates. This proposal is examined in the light of contemporary work and it is concluded that the major factor is the accumulation of metabolites brought about by the autocatalytic action of the Benson‐Calvin cycle. Light activation of ribulose diphosphate carboxylase is seen as an important factor in autocatalysis but normally too rapid a process, in itself, to account for delays of several minutes.
STUDIES ON TUBERIZATION IN SOLANUM ANDIGENA: I. EVIDENCE FOR THE EXISTENCE AND MOVEMENT OF A SPECIFIC TUBERIZATION STIMULUS
Authors: KUMAR D. , WAREING P. F. 
Published: May 2006

SUMMARYExperiments were carried out with a clone of Solanum andigena, which requires short photo‐periods for tuberization, to investigate whether or not tuberization involves a specific stimulus. It was shown that a tuberization stimulus can be transmitted by grafting induced on to non‐induced shoots and that even small pieces of stem from induced plants are capable of transmitting the stimulus. The results of these and other experiments support the view that tuberization is determined by a specific stimulus, rather than by the availability of non‐specific photosynthates. It is shown that the stimulus can move both basipetally and acropetally, but tuber development occurs only at the physically lowest nodes of stem cuttings, whether these are normally orientated or inverted.