bluuebunny/crossref_metadata_2025_split huggingface dataset:
A RADIOCARBON‐DATED POLLEN DIAGRAM FROM VALLEY BOG, ON THE MOOR HOUSE NATIONAL NATURE RESERVE
Authors: CHAMBERS CARL 
Published: May 2006

SUMMARYA radiocarbon‐dated pollen diagram from Valley Bog, situated in the upper reaches of Tees‐dale, is discussed. It provides evidence for a late alder expansion and the possibility of Mesolithic human activity on the Moor House National Nature Reserve. When compared with pollen diagrams from lowland County Durham there appears to be a delay in the elm decline at the high altitude. The elm decline is followed by a phase of Bronze Age deforestation which precedes a similar but more prolonged and pronounced Iron Age clearance.
PREPARATION OF PLANT MITOCHONDRIA USING GEL FILTRATION COLUMNS
Authors: HARLEY J. L. , BLACK M. K. , WEDDING R. T. 
Published: May 2006

SUMMARYThe possibility of preparing plant mitochondria using Sephadex or Bio‐gel columns was investigated. It is concluded that gel filtration is a feasible alternative to centrifugation with many plant materials. It has the advantage of providing preparations of higher O2 uptake rate per unit protein with similar or better ADP/O or respiratory control ratios than centrifugation. It is often also more rapid for routine preparation. Its disadvantage in particular is the dilution of the final suspension.
CARBOHYDRATE AND INOSITOL METABOLISM IN THE SEAGRASS, CYMODOCEA NODOSA
Authors: DREW EDWARD A. 
Published: May 2006

SUMMARYLeaves of the seagrass Cymodocea nodosa contained more than 5% dry weight of both sucrose and an inositol, identified as 1‐chiro‐inositol. Sucrose was consumed during dark starvation at a rate suggesting it was a major respiratory substrate whereas the l‐chiro‐inositol content remained unaltered even after all the sucrose had been utilized. About 90% of photosyn‐thetically fixed carbon was incorporated into sucrose initially; some of this was converted into insoluble compounds during subsequent dark starvation. Glucose, fructose and the two inositol isomers, myo‐ and l‐chiro‐inositol, were also formed during photosynthesis. These inositols each accumulated about 1.2% of the fixed carbon and it was calculated that even this low rate of synthesis could account for at least 50% of new l‐chiro‐inositol required to maintain its concentration in new tissue. Myo‐inositol was not accumulated above a fraction of a percent dry weight and its active incorporation into insoluble material was demonstrated. Both inositols were synthesized to some extent from exogenously supplied glucose and sucrose but exogenous myo‐inositol initially accumulated as such within the tissues before incorporation into the insoluble fraction and none was converted to the l‐chiro isomer. It was concluded that 1‐chro‐inositol was synthesised from glucose rather than by epimerisation of myo‐inositol. l‐chiro‐inositol, which had no direct osmoregulatory role as its content neither increased at high salinities nor decreased at low salinities, appeared to be metabolic‐ally inert. Small quantities of muco‐inositol were also detected in Cymodocea. This too appeared to metabolically inert and both 1‐chiro‐inositol and muco‐inositol seemed to be byproducts of the cyclization of glucose to myo‐inositol.
THE EFFECTS OF ETHANOL ON ROOTING AND CARBOHYDRATE METABOLISM IN STEM CUTTINGS OF PHASEOLUS AUREUS ROXB.
Authors: MIDDLETON W. , JARVIS B. C. , BOOTH A. 
Published: May 2006

SUMMARYThe number of roots induced by indolebutyric acid (IBA)in cuttings of light‐grown seedlings of Phaseolus aureus Roxb. is greatly inhibited by high levels of ethanol. When supplied alone to cuttings of dark‐grown seedlings increasing concentrations of ethanol progressively reduce the number of roots. The ethanol is glycosylated, at least in part, to ethyl‐β‐glucoside which reaches concentrations several‐fold greater in cuttings of light‐grown seedlings compared to those of dark‐grown seedlings. In the hypocotyl of cuttings from light‐grown seedlings the glucoside constitutes 26% of the extracted sugar and 1100 μg/g fresh weight after a treatment of 18 h with 2 ml/1 ethanol.
THE BORON REQUIREMENT FOR ROOT DEVELOPMENT IN STEM CUTTINGS OF PHASEOL US AUREUS ROXB.
Authors: MIDDLETON W. , JARVIS B. C. , BOOTH A. 
Published: May 2006

SUMMARYNo roots develop in cuttings from light‐grown seedlings of Phaseolus aureus Roxb. without exogenous boron, irrespective of auxin pretreatment. Root numbers and lengths are severely restricted unless the supply of boron is optimal. When supplied in equal molarities, indole‐butyric acid (IBA) is far more effective than indoleacetic acid in promoting root number. Very small visible roots do develop on cuttings from dark‐grown seedlings in the absence of applied boron. The growth of such roots is promoted by boron although there is an inverse correlation between length and number. IBA is far less effective at increasing root number in cuttings of dark‐grown seedlings.
REGENERATION OF MERISTEMATIC ACTIVITY FOLLOWING DECAPITATION OF THE ROOT TIP OF VICIA FABA L.
Authors: FRANCIS DENNIS 
Published: May 2006

SUMMARYThe numbers of primordia and secondary roots present in the terminal 5 mm of roots of Vicia faba were scored over the 6‐day period following the removal of 2, 10 or 20 mm of the root tip and compared with the corresponding numbers found in 5‐mm long segments of intact roots which were 2–7, 10–15 and 20–25 mm basal to the tip of the meristem at the start of the experiment (C2 segments). 144 h following decapitation the numbers of laterals emerging from the apical 5 mm of each batch of decapitated roots were greater than those in the corresponding C2 segments, the greater number in this part of the former roots reflecting the emergence of secondary roots through the cut surface at the stump apex in addition to those emerging laterally. The time course for complete secondary root formation in the apices of each batch of decapitated roots was no different from that in the intact controls.In contrast to the changes which took place at the root apex following the removal of 2 mm or more of tissue, the removal of the apical 0.5 mm of the root in addition to the cap resulted in regeneration of a meristem from the proliferating cells which remained behind at the time of decapitation. The latter type of regeneration was investigated by following the changes which took place in mitotic index, labelling index and the relative proportions of interphase nuclei with different amounts of DNA in the apical 2 mm of roots from which the apical 0.5 mm of the meristem had been removed over the 144 h period between decapitation and the resumption of normal root growth.
SEASONAL VARIATION OF GORSE (ULEX EUROPAEUS L) SURFACE WAX AND TRICHOMES
Authors: ZABKIEWICZ J. A. , GASKIN R. E. 
Published: May 2006

SUMMARYA marked seasonal variation in wax production was observed by scanning electron microscopy and confirmed by extraction and weighing the wax. Contact angles of water droplets on films of this extracted wax also showed seasonal variation as well as differences between foliage of different ages. This suggests that the chemical composition of the wax could vary in a like manner. Trichome development patterns were less distinct, but there was some indication of progressive attrition with increasing tissue age.
VARIATION IN FOUR POPULATIONS OF SENECIO VISCOSUS L. AS REVEALED BY A CULTIVATION EXPERIMENT
Authors: AKEROYD J. R. , WARWICK S. I. , BRIGGS D. 
Published: May 2006

SUMMARYFrom fruits of Senecio viscosus L., collected on three coastal shingle beaches and at one inland site, plants were grown in a garden trial, which revealed statistically significant differences between and within the four populations. Particularly distinctive were the early‐flowering dwarf plants raised from fruits collected from coastal shingle at Thorpeness.Bagging of capitula indicated that S. viscosus is self‐compatible, although within‐family variances and the frequency of insect visits to the experiment suggest that outcrossing occurs. Further experiments and observations are necessary to establish the frequency of self‐ and cross‐fertilization in natural populations of the species.The implications of the experiment, as regards the distribution and genecology of S. viscosus in Britain, are discussed, with special emphasis on the differences between coastal shingle populations.
NUMERICAL TAXONOMY OF SPECIES IN ALLIUM SUBGENUS MOLIUM
Authors: BADR A. , ELKINGTON T. T. 
Published: May 2006

SUMMARYNumerical methods have been used to study the relationships between twenty‐two operational taxonomic units (O.T.U.'s) in Allium subgenus Molium Koch (Wendelbo). Data were obtained by investigating fifty‐five morphological and cytological characters and thirty‐one chemical characters, the latter being volatiles, mainly sulphides, derived from bulb tissue. The CLASP programme was used to produce a number of phenetic classifications firstly by hierarchical cluster analyses, the results being presented as dendrograms showing percentage similarities of O.T.U.'s and as minimum spanning trees (M.S.T.), and, secondly, by principal co‐ordinates analyses, the results being presented as vector plots. Three sets of classifications have been produced; the first employing the morphological and cytological characters on all twenty‐two O.T.U.'s, the second using chemical data on only fifteen O.T.U.'s and the third using all characters.The O.T.U.'s have been divided into six major groups as follows: (a) A. cernuum; (b) A. triquetrum and A. paradoxum; (c) A. oreophilum and A. oreophilum cv. Zwanenburg; (d) A. erdelii; (e) A. zebdanense, A. roseum, A. roseum var. bulbiferum, A. subvillosum, A. neapolitanum, two subspecies of A. trifoliatum and A. subhirsutum; (f) A. moly, A. scorzonerifolium, A. geyeri, A. unifolium, A. fibrillum, A. acuminatum and A. dichlamydeum. These groups and their subgroups are discussed in the light of biosystematic studies, particularly the ability of taxa to cross with others. The phenetic classifications produced are also compared with the previous taxonomic arrangements of the subgenus.
EVOLUTIONARY ASPECTS OF WIND POLLINATION IN THE GENUS PLANTAGO (PLANTAGINACEAE)
Authors: PRIMACK RICHARD B. 
Published: May 2006

SUMMARYThe selective forces acting to maintain a copious production of uniformly sized pollen grains in wind‐pollinated plants were investigated among species in the genus Plantago and at the population level in P. lanceolata. The species with cleistogamous (closed) flowers produce far less pollen of more variable average diameters than the species with chasmogamous (open) flowers. Pollen grains of P. lanceolata captured by stigmas of female plants were smaller than a general sample of pollen collected from the anthers of perfect plants, indicating that large pollen grains are not as effective as small grains in wind dispersal. The rapid decrease in pollen density on the stigmas of P. lanceolata with increasing distances from the pollen sources suggests that plants of this self‐incompatible species must produce great amounts of pollen in order to pollinate nearby plants. The cost of this high pollen production associated with wind pollination can be seen in P. lanceolata in the increased production of reproductive tissue and larger seeds in female plants when compared with normal plants.
A NEW METHOD FOR THE PREPARATION OF CLAY‐RICH SEDIMENT SAMPLES FOR PALYNOLOGICAL INVESTIGATION
Authors: BATES C. D. , COXON P. , GIBBARD P. L. 
Published: May 2006

SUMMARYThe use of sodium pyrophosphate as an effective deflocculant for the removal of clay from sediment samples is described.Tests on the action of the chemical on samples from a number of geographically and chronologically separated localities has shown almost complete removal of clay. No evidence from the tests suggests that pollen is attacked, preferentially destroyed or lost by this treatment.
SEASONAL PATTERNS OF FRUCTAN METABOLISM IN FORAGE GRASSES
Authors: POLLOCK C. J. , JONES T. 
Published: May 2006

SummaryFructan levels and mean molecular weights were measured throughout the year in leaves and stems of four forage grasses. In contrast to other studies, the major period of fructan synthesis in all varieties was autumn and winter, with maximal values in December. Extensive hydrolysis, accompanied by a decline in mean molecular weight, occurred between January and April. Fructan accumulation was maximal in periods when growth was restricted and the properties of the synthetic system are discussed in relation to the patterns of growth of temperate forage grasses.
CELL DEATH AS A FUNCTIONAL EVENT IN THE DEVELOPMENT OF THE LEAF INTERCELLULAR SPACES IN AVICENNIA MARINA (FORSSKÅL) VIERH
Authors: CHALAIN T. M. B. de , BERJAK P. 
Published: May 2006

SummaryExamination of successive development stages of the leaf of Avicennia marina (Forsk.) Vierh has revealed that although a measure of early schizogeny occurs, formation of the major air spaces is by a process of lysigeny. A developmental sequence terminating in autolysis may be traced within cells forming a localized group, and the end products of the breakdown are identifiable as debris of a clearly cellular origin, which occurs within the newly created intercellular space.
THE ULTRASTRUCTURE OF POLLEN‐GRAIN DEVELOPMENT IN THE OLIVE (OLEA EUROPAEA). 1. PROTEINS IN THE PORE*
Authors: PACINI E. , JUNIPER B. E. 
Published: May 2006

SummaryThe olive tapetum is of the parietal type and the walk of the tapetal cells disappear at about the time as the microspore tetrads separate. As the intine starts to develop in the microspore the Golgi bodies are apparently active in discharging vesicles, and fibrillar PAS‐positive material starts to accumulate between an undulant plasmalemma and the intine. The plasmalemma then retracts from the pore zone and within the crescent‐shaped area thus formed accumulates what is believed to be a pectocellulosic wall much penetrated by invaginating tubules from the plasmalemma. After the first haploid mitosis more material forms between the plasmalemma and the pore apparently sealing off these invaginations. Fibrillar material thought to be protein first appears in the intercellular spaces between the tapetal cells and finally becomes concentrated over the outer surface of the pollen pore. This proteinaceous material does not accumulate if the cytoplasm of the pollen has degenerated prior to pore formation.
POLLINTATION ECOLOGY OF, AND HYBRIDIZATION BETWEEN, ORCHIS CORIOPHORA L. AND O. COLLINA SOL. EX RUSS. (ORCHID ACEAE) IN ISRAEL
Authors: DAFNI A. , IVRI Y. 
Published: May 2006

SummaryThe flower of Orchis coriophora L. contains free nectar in the spur and is very fragant; it attracts a large gallery of pollinators mainly Apis mellifera. The capsule production rate is about 90% O. collina Sol. ex Russ. has empty spurs and is scentless; pollinators are scarce and capsule production rate is about 25%.The species are sympatric in some habitats in Israel and create rare hybrids which seem to be the result of common pollinators.It is suggested that each of the two species represents different pollination strategy in the genus. This view and the implications on self and cross pollination are discussed.
THE INFLUENCE OF SOIL pH ON THE EFFICIENCY OF VEICULAR‐ARBUSCULAR MYCORRHIZA
Authors: GRAW D. 
Published: May 2006

Summary Tagetes minuta and Guizotia abyssinica reacted differently to changes in soil pH and to fertilization with various phosphates in spite of inoculation with the same strain of Glomus macrocarpus. At pH 4.3, mycorrhizal Guizotia was unable to absorb P from all the compounds with the result that growth was severely inhibited by inoculation, whereas mycorrhizal Tagetes grew well at this pH in the presence of Ca(H2PO4)2. H2O, Ca5(PO4)3OH and AlPO4. Phosphorus uptake and growth of mycorrhizal Guizotia were improved at pH 5‐6 and surpassed the performance of non‐mycorrhizal plants at pH 6‐6. Growth of mycorrhizal Tagetes was reduced at pH 5.6 in the presence of Ca(H2PO4)2. H2O and Ca5(PO4)OH, but improved at pH 6.6 in all treatments with the exception of Ca5(PO4)3OH as P source.
FLORAL MORPHOLOGY AND POLLEN FLOW IN THE HETEROSTYLOUS SPECIES PULMONARIA OBSCURA DUMORT (BORAGINACEAE)
Authors: OLESEN JENS MOGENS 
Published: May 2006

SummaryPollen flow in the heterostylous species P. obscura was studied in two localities in Denmark. Various floral characters of the two morphs were measured, but differences were found only in height of stamens and stigma, and size of pollen. In studies with a scanning electron microscope (s.e.m.) pollen was discovered to have a continuous, equatorial girdle formed by the transverse furrows extending laterally from the ora. The stigmatic papillae were composed of a stalk with a many‐armed crown. The ratio of number of thrum to pin plants was approximately 1:1 fulfilling theoretical expectations. Six different Bombus spp. and a specimen of Psithyrus bohemicus were observed as visitors to P. obscura, which displays a range of adaptations to Bombus pollination. Thirty per cent of the Bombus specimens had corbicular pollen loads, which were almost 100% pure Pulmonaria pollen. Pollen flow was revealed by analysing the pollen loads on stigmas and proboscides. Both stigma types had more illegitimate pollen than expected on the basis of the ratio of production of the two pollen types. This could be caused by a high degree of intrafloral pollen flow. Since heterostyly does not apparently enhance the transport of legitimate pollen the adaptive role of the system is unclear.
REVERSAL OF THE CO2‐RESPONSES OF STOMATA BY FUSICOCCIN
Authors: Travis A. J. , Mansfield T. A. 
Published: May 2006

SummaryThe fungal toxin fusicoccin, which is known to stimulate stomatal opening, has been found to reverse the response of stomata to CO2. In the absence of fusicoccin, CO2 caused stomata to close, while in its presence, CO2 caused opening. This reversal of events was even more striking in epidermal malate levels. Three hundred and fifty μl l−1 CO2 normally suppressed malate formation, but in the presence of fusicoccin, amounts of malate were greater in 350 μl l−1 CO2 than in CO2‐free air.These observations might be best explained if CO2 exerts two different effects on guard cells, one of which is normally obscured by the other. The familiar effect, that of stomatal closure in response to increases in CO2 concentration, is predominant, and it is suggested that this involves control of potassium ion uptake either through the activity of an electrogenic proton pump or through membrane permeability to K+. Fusicoccin has the effect of annulling this form of control by CO2, revealing an opposing response, namely a stimulation of opening by CO2. This could be due to a fixation of CO2 into malate, which is used as a counter ion for K+ in guard cells. There is, however, an enigma: the fact that (in the presence of fusicoccin) malate level is positively correlated with external CO2 supply suggests that the latter limits the rate of malate formation, yet incorporation of labelled CO2 can only account for about 1 % of the malate produced.
THE EFFECT OF NITRITE ON ROOT GROWTH OF BARLEY AND MAIZE
Authors: Lee R. B. 
Published: May 2006

SummaryWhen sodium nitrite (1 mM) was added to a nitrate‐based nutrient solution, initially at pH 5, it had a small but consistently adverse effect on elongation of the seminal roots of barley and maize. In larger plants of maize, the length and dry wt of the nodal roots, and the dry wt of the shoots, were also decreased. The roots of both species were more sensitive to nitrite during growth under oxygen‐deficient conditions than when grown in solutions well supplied with air.The concentration of nitrate in the roots of barley plants decreased when 1 to 3 mM nitrite was included in the nutrient solution.It is suggested that nitrite toxicity is unlikely to be of importance in the survival of cereal roots in temporarily waterlogged soils save under the most abnormal circumstances.
STUDIES ON THE EFECTS OF LOW LEVELS OF SULPHUR DIOXIDE ON THE GROWTH OF LOLIUM PERENNE L.
Authors: BELL J. N. B. , RUTTER A. J. , RELTON J. 
Published: May 2006

Summary Lolium perenne L. cv. S23 was grown in Perspex chambers situated out of doors and ventilated with clean air or controlled levels of sulphur dioxide (SO2). Fumigations were carried out with [SO2] ranging from 43 to 423 μg m−3 for periods up to 194 days under both summer and winter conditions.Concentrations as low as 43 μg m−3 for 173 days in winter and 106 μg m−3 for 194 days in summer could produce reductions in shoot dry wt but, in some experiments, similar or higher concentrations had no effect on growth. This difficulty in obtaining a clear dose/response relationship is possibly due to an interaction of environmental factors with the effects of the pollutants. In some of the experiments, growth was reduced in the absence of any detectable symptoms whereas, in other cases, the fumigated plants became chlorotic. There was some evidence for chronic SO2 injury being more severe on young plants.SO2 acted primarily through a depression in net assimilation rate. No clear correlation was found between either chlorophyll content or total sulphur content of the fumigated plants and a reduction in any of the growth parameters investigated. The results are discussed in relation to those of other workers and their relevance to conditions in the field in the United Kingdom.
SENSITIVITY OF ROOTING AND TOLERANCE TO COPPER IN AGROSTIS TENUIS SIBTH.
Authors: NICHOLLS M. K. , McNEILLY T. 
Published: May 2006

SummaryThe rooting response of seven populations of Agrostis tenuis Sibth. to a range of copper concentrations in calcium nitrate solution is described. Variation in both index of tolerance and sensitivity of rooting to increased copper levels were found and shown to be phenotypically independent characters. It is suggested that rooting sensitivity to a range of copper concentrations provides a further measure of copper tolerance which is independent of the methods previously employed for assessing tolerance.
PLANT GROWTH RESPONSES TO VESICULAR‐ARBUSCULAR MYCORRHIZA
Authors: OWUSU‐BENNOAH E. , MOSSE BARBARA 
Published: May 2006

SummaryOnions, lucerne and barley were inoculated with one of two endophytes placed below the seed in a replicated field trial. After 13 weeks shoot growth was increased by 77% (onion), 79% (lucerne) and 33% (barley) with one inoculum and by four‐, six‐fold and 30 % respectively with the other. Lucerne and onion benefitted most from inoculation in the sub plots with most available P whereas barley responses were confined to those with less available P.The uninoculated plants reached approximately 45% infection from indigenous endophytes and the inoculated plants around 70%. Inoculation responses were not related to infection level. One introduced endophyte spored profusely and spread 22 cm from the point of inoculation, the other formed only few new spores; the indigenous fungi hardly sporulated at all. Spore production was little affected by host species or soil P level and was unrelated to percentage root infcetion.The rationale of field inoculation is discussed with particular reference to amounts of inoculum required.