bluuebunny/crossref_metadata_2025_split huggingface dataset:
INTERVENTION BY GIBBERELLIN AND CYTOKININ IN THE RELEASE OF APPLE EMBRYOS FROM DORMANCY: A REAPPRAISAL
Authors: BULARD C. 
Published: May 2006

SummaryEmbryos of Pyrus malus L. cv. Golden delicious, were isolated from the fruits and cultivated in aseptic conditions on solid media. Rate of cotyledon greening, evolution of germination percentage and growth of organs after germination were used to determine the extent of dormancy. Treatment with gibberellins and by chilling both induced an increase in the rate of cotyledon greening, in germination percentage as well as stimulating root growth. However, even the most active gibberellins, GA4, GA7, GA9, applied simultaneously at high concentration (5 mg l−1), could not completely reproduce the effects of optimum chilling treatment (9 to 12 weeks at 5 °C).While progressive increases in germination percentages were found with duration (chilling) or concentration (gibberellins), there was no direct relationship between concentration and response in the case of kinetin. Low concentrations (10 or 100 ug l−1) were inactive, whereas concentrations equal to or greater than 1 mg l−1 induced large increases in germination percentage. The concentrations which stimulated germination also inhibited growth, especially of the root.
TANSLEY REVIEW No 3. THE STRUCTURE AND SYNTHESIS OF PLANT LECTINS
Authors: LORD J. M. 
Published: May 2006

SummaryLectins are a group of proteins and glycoproteins which possess specific binding sites for particular sugars. They are very abundant in certain plant tissues, for example the seeds of legumes. Although their biological role in plants has not been convincingly explained, details of their structure, synthesis and molecular biology are beginning to emerge.

Contents

Summary
351

I.
Introduction
351

II.
Structure of lectins
352

III.
Synthesis of lectins
359

IV.
Conclusion
363

References
363
EFFECT OF GROWTH CONDITIONS ON NADPH‐SPECIFIC GLUTAMATE DEHYDROGENASE ACTIVITY OF EUGLENA GRACILIS
Authors: FAYYAZ‐CHAUDHARY M. , JAVED QAMAR , MERRETT MICHAEL J. 
Published: May 2006

SummaryCells of Euglena gracilis Klebs, strain z Pringsheim, had high NADPH‐glutamate dehydrogenase (GDH) activity when grown on glutamate but activity was repressed completely in cells grown on ammonium (NH4+). Subcellular fractionation showed that NADPH‐GDH activity was located exclusively in the cytosol, while glutamine synthetase was present in the cytosol and chloroplasts. Despite high NADPH‐GDH activity NH4+ assimilation was completely inhibited by methionine sulphoximine (MSO), an inhibitor of glutamine synthetase. With MSO present, cells produced NH4+ and it was shown that greatest NH4+ production occurred with cells containing high levels of NADPH‐GDH activity and plentiful carbon supply. It is concluded that NADPH‐GDH has a catabolic function in Euglena generating NH4+ from glutamate under conditions of nitrogen limitation.
GERMINATION RESPONSES TO LIGHT AND ALTERNATING TEMPERATURES IN EUROPEAN POPULATIONS OF DACTYLIS GLOMERATA L.
Authors: PROBERT R. J. , SMITH R. D. , BIRCH P. 
Published: May 2006

SummaryA direct linear relationship between germination responses to light and alternating temperatures and storage period was recorded when seeds of three populations of Dactylis glomerata L. of contrasting origin were stored under cool dry laboratory conditions (15°C, 15% r.h.). Under these conditions the rate of after‐ripening in two batches of a Mediterranean population were independent of original dormancy level but lower than in populations originating from southern England and Western France. The effects of storage on germination responses were additive in all cases. In contrast, when seeds of a population from southern England were stored under natural conditions of temperature and humidity from August to April germination behaviour was dependent on the conditions used in germination tests. Evidence is presented that the rate of loss of primary dormancy under natural conditions exceeded that which occurred during controlled storage in the laboratory. An apparent simultaneous loss of primary dormancy and induction of secondary dormancy observed when seeds were stored under natural conditions is discussed. Dry storage at −75°C effectively arrested after‐ripening over a period of 110 weeks.
RECENT ACCUMULATION AND EROSION OF BLANKET PEAT IN THE WICKLOW MOUNTAINS, IRELAND
Authors: BOWLER MÁIRE , BRADSHAW RICHARD 
Published: May 2006

SummaryActive peat erosion is widespread in the Wicklow mountains, and it has been suggested that peat accumulation has slowed or ceased in the area associated with the erosive processes. Analysis of the recent deposition of pollen and magnetic minerals at three sites shows that significant quantities of peat (6.5 to 16.5 cm) have accumulated within the last 150 years. The fallout of magnetic pollutants is far below that found in the Pennine peats, ruling out certain hypotheses about the causes of montane blanket peat erosion.
ANION ACCUMULATION BY THE MOSS HYLOCOMIUM SPLENDENS: UPTAKE AND COMPETITION STUDIES INVOLVING ARSENATE, SELENATE, SELENITE, PHOSPHATE, SULPHATE AND SULPHITE
Authors: WELLS J. M. , RICHARDSON D. H. S. 
Published: May 2006

SummaryArsenic and selenium uptake by the moss Hylocomium splendens (Hedw.) Br. et Sch. from solutions containing arsenate, selenite or selenate ions was investigated. Arsenate and selenite were accumulated only by living shoots. This moss was unable to take up selenate. Arsenate uptake was optimal between pH 3 and 5 whilst selenate uptake was greatest at pH 3. This difference is discussed in terms of speciation of these anions in solution.Uptake of arsenate and selenite displayed saturation kinetics at pH 5 which could be described in terms of Michaelis‐Menten parameters with Km values of 418 ± 56 μM and 451±93 μM for arsenate and selenite respectively.Competition studies revealed that pre‐incubation of moss shoots in phosphate solutions did not affect the subsequent uptake of either arsenate or selenite. However, the uptake of the latter ions was decreased if phosphate was included in the incubation medium. Phosphate was a competitive inhibitor of arsenate uptake with an inhibition constant (Km phosphate) of 82 μM. Phosphate and arsenate were non‐competitive inhibitors of selenite uptake with inhibition constants of 225 and 43 μM for phosphate and arsenate respectively. The results suggest that arsenate and selenite were accumulated via separate transport systems in H. splendens and it is proposed that these systems may normally be responsible, in part, for phosphate uptake by this moss.
ULTRAVIOLET PATTERNS IN THE TRAPS OF CARNIVOROUS PLANTS
Authors: JOEL D. M. , JUNIPER B. E. , DAFNI A. 
Published: May 2006

SummaryA survey of u.v. patterns in the traps of carnivorous plants reveals that, similar to many flowers, certain traps show conspicuous u.v. patterns. These patterns are based on both u.v.‐absorption by the plant surface itself and u.v.‐absorption by nectar or pools of the digestive secretion. The results are discussed with respect to the possibility that u.v. patterns may attract prey to certain carnivorous plants.
STRUCTURE AND FUNCTION IN THE GRASS LIGULE: PRESENCE OF VEINED AND MEMBRANOUS LIGULES ON THE SAME CULM OF BRITISH GRASSES
Authors: CHAFFEY N. J. 
Published: May 2006

SummaryFifty‐six grass species, representing 18 tribes, were examined for the presence of both veined and membranous ligules in the same culm. This phenomenon was found in only nine species –Agrostis gigantea Roth., A. stolonifera L., Alopecurus pratensis L., Holcus lanatus L., H. mollis L., Phleum pratense L., Phalaris arundinacea L., Dactylis glomerata L. and Poa trivialis L. The abaxial epidermal anatomy of both ligule types is described for each species; the main differences noted were the presence of vascular tissue with associated chlorenchyma and stomata in the veined ligules. This heteroligulate condition is discussed in relation to possible functions of the grass ligule.
CARBOHYDRATE METABOLISM IN THE FUNGUS DENDRYPHIELLA SALINA
Authors: WETHERED J. M. , METCALF E. C. , JENNINGS D. H. 
Published: May 2006

SummaryWhen Dendryphiella salina was grown on non‐saline media, mannitol and arabitol were the only polyols present in the mycelium. In media made up with sea‐water or salinized by high concentrations of salts of potassium, sodium and magnesium, glycerol was also present. When mycelium grown in sea‐water was transferred to distilled water, the glycerol content dropped very rapidly to zero. The amounts of mannitol and arabitol also declined. Transfer of similarly grown mycelium to sea‐water alone reduced the rate of decline of glycerol, caused little change in the amount of mannitol and induced a rise in that of arabitol. These observations help to explain the absence of glycerol in mycelium in previous studies. The concentration (mol l−1) of solutes within mycelium were determined after 48 h growth in the presence of either sodium chloride, magnesium chloride, sodium sulphate, inositol or betaine at either 0.4 or 0.8 osmol kg−1water. There was a very similar total polyol concentration at each osmolality in the saline media irrespective of the salt, even though there could be different concentrations of individual polyols. With inositol in the medium, the same held if the endogenous concentration of that compound was included in the total. The same did not hold for betaine, in which medium growth was poor. The total polyol concentration increased in all cases with the osmolality of the medium. With respect to the total concentration of solutes present (excluding data for mycelium grown in betaine), polyols were 19 to 33 % of the total, α‐amino nitrogen, 11 to 34% and organic acids, 0 to 8 %. These percentages take into account data obtained by 24Na‐flux studies, which indicate that, in media containing sodium salts, much of the mycelial content of the cation may be located in the wall.
MYCOPHAGOUS MARSUPIALS AS DISPERSAL AGENTS FOR ECTOMYCORRHIZAL FUNGI ON EUCALYPTUS CALOPHYLLA AND GASTROLOBIUM BILOBUM
Authors: LAMONT BYRON B. , RALPH CATHERINE S. , CHRISTENSEN PER E. S. 
Published: May 2006

SummaryThe marsupial, Bettongia penicillata (Gray), is the major consumer of hypogeous fungi in eucalypt forest at Perup, Western Australia. The rate of excavation of sporocarps increases after fire.The spores of at least 18 fungi were indicated in faecal pellets, 10 of which could be assigned to hypogeous sporocarps present at the site. Most spores belonged to the ectomycorrhizal genus Mesophellia.Faecal pellets applied to seedlings of Eucalyptus calophylla R.Br. and Gastrolobium bilobum R. Br. in autoclaved soil induced the formation of seven ectomycorrhizal types accompanied by a marked stimulation of growth compared with the controls. Inoculation with fresh spores of two Mesophellia species failed to produce mycorrhizas, suggesting that digestion may be the usual pre‐treatment for germination.It is concluded that this mammal is a reliable and efficient dispersal and inoculation agent for ectomycorrhizal fungi via its faeces, and that it plays a key role in re‐establishment of vegetation after fire.
VARIATION IN MORPHOLOGICAL AND PHYSIOLOGICAL TRAITS ASSOCIATED WITH YIELD IN LIMNANTHES SPP.
Authors: KREBS S. , JAIN S. K. 
Published: May 2006

SummaryBiomass and seed yield variation among 10 accessions of two Limnanthes species, L. alba Benth. and L. douglasii R. Br., was examined by way of a yield component analysis involving 17 morphological characters. Seed yield estimates ranged from 735 to 1680 kg ha−1. While both taxa contained populations with high yield potential, species differences in phenology and resource allocation suggested different strategies for yield optimization. L. douglasii accessions produced large quantities of small‐sized seed, whereas L. alba entries maximized seed size at the expense of seed number, seed size and seed number being compensating components of yield in both species. Higher yields were associated with rapid initial growth and leaf development in L. douglasii, while delayed biomass accumulation and less leaf area appeared more favourable to seed production in L. alba. Early and asynchronous floral development were strong predictors of high yielding ability in both taxa. Selection for individuals which flower early and over a long period of time, with a higher seed output associated with a larger proportion of total above‐ground dry matter allocated to reproduction, was suggested as an appropriate breeding strategy in either species. Concurrent improvement of seed number and seed size may prove possible by indirect selection for fewer flowers per plant in L. douglasii or more flowers per plant in L. alba accessions, through manipulation of primary branch length and number.
THE EFFECT OF WATERLOGGING ON SEEDLINGS OF EUCALYPTUS MARGINATA
Authors: DAVISON E. M. , TAY F. C. S. 
Published: May 2006

SummaryThree‐ to four‐month‐old Eucalyptus marginata Donn ex Sm. (jarrah) were grown in the glasshouse in peat/sand at 20 °C root temperature, and either waterlogged continuously for up to 14 d, or waterlogged for a shorter time and then drained. During waterlogging, the O2 concentration of the soil solution declined to less than 1 mg l−1within 1 d. There was an increase in the resistance to water movement into or through the plant within 4 d of flooding the pots. The number of xylem vessels blocked by tyloses increased with the duration of flooding, and did not increase further when waterlogging ceased. The transpiration rate of plants continuously waterlogged and maintained in a dry atmosphere for 13d was closely correlated (r =− 0.98) with the proportion of occluded vessels in the tap‐root. The rate at which wilting developed depended on both the duration of waterlogging and the transpiration rate.
REQUIREMENT FOR A LONG LAG PERIOD FOR THE INDUCTION OF NITRATE REDUCTASE IN WHEAT (TRITICUM AESTIVUM) EMBRYOS DURING GERMINATION
Authors: DISA SUHAS , GUPTA ADITYA , GUHA‐MUKHERJEE SIPRA , SOPORY SUDHIR K. 
Published: May 2006

SummaryThe induction of nitrate reductase (NR) in the embryos of wheat required a period of 20 h of incubation in nitrate during the early stages of seed germination. The lag phase in the development of NR activity was not due to the non‐availability of nitrate in the embryos, the presence of a nitrate reductase inactivating factor, or the synthesis of inactive NR. At the onset of the inducible phase the enzyme was synthesized de novo, but was not dependent on the synthesis of fresh m‐RNA. Protein synthesis during the lag phase was essential for the subsequent induction of NR in the inducible phase.
ZINC TOLERANCE IN BETULA
Authors: BROWN M. T. , WILKINS D. A. 
Published: May 2006

SummarySeed samples of Betula spp. from Zn‐contaminated and control sites were cultured on agar with added Zn. The samples from contaminated soils were more Zn tolerant than the controls. Detailed work on clonal material showed differences of tolerance within samples.Reducing the concentration of other ions, especially Ca, increased the toxicity of Zn. Chemical analyses of leaf material showed reduced uptake of Zn (a) in tolerant plants, and (b) in plants treated with high levels of Ca.
ZINC TOLERANCE OF MYCORRHIZAL BETULA
Authors: BROWN M. T. , WILKINS D. A. 
Published: May 2006

SummarySeedlings of Betula spp. were grown in conjunction with isolates of Amanita muscaria Hooker and Paxillus involutus Fr. under aseptic conditions. Mycorrhizas were established in sterilized peat and vermiculite to which nutrient media had been added. Zinc was supplied at various levels and growth of the host was assessed after eight weeks. The mycorrhizas increased the tolerance to Zn of both tolerant and non‐tolerant Betula. This was coupled with a reduction in the translocation of zinc to the shoots of Betula, but an accumulation of zinc in the mycorrhizas.
SALT STRESS DISTURBS THE CALCIUM NUTRITION OF BARLEY (HORDEUM VULGARE L.)
Authors: LYNCH JONATHAN , LÄUCHLI ANDRÉ 
Published: May 2006

SummarySoil salinity decreased the Ca contents of shoots of two cultivars of barley (Hordeum vulgare L.) grown under field conditions, particularly in younger leaves. Reduction in Ca content was more pronounced in cv. Arivat (the more salt‐sensitive cultivar) than in cv. Briggs. In seedlings grown in solution culture, relatively low concentrations of NaCl inhibited the transport of Ca to the shoot. This inhibition was not due to effects of NaCl on Ca influx into the root or on transpiration. We propose that NaCl inhibits Ca transport from root to shoot by interfering with the release of Ca into the root xylem, possibly via an effect on the active loading of Ca into xylem vessels.
IMPLICATION OF HYDROGEN PEROXIDE – ASCORBATE SYSTEM ON MEMBRANE PERMEABILITY OF WATER STRESSED VIGNA SEEDLINGS
Authors: MUKHERJEE S. P. , CHOUDHURI M. A. 
Published: May 2006

SummaryWhen seedlings of Vigna catjang were subjected to increasing magnitudes of water stress (−0.5, −10 and −1.5 MPa) the induced changes in leaf water potential (LWP), were accompanied by increases in proline content, tissue permeability, H2O2 content and ascorbic acid oxidase activity, and decreases in catalase activity and ascorbic acid content.Pretreatment with L‐cysteine (10−3 M), reduced glutathione (10 −3 M) and abscisic acid (ABA, 10−4 M) through the roots improved the water status of stressed seedlings maintained at – 10 MPa for 2 d, and decreased the tissue permeability, proline content, H2O2 content and ascorbic acid oxidase activity, but increased the ascorbic acid content and catalase activity. Stressed seedlings from seeds pretreated with CaCl2 (10−2 M) behaved like plants treated with the reducing agents and ABA, and not like untreated stressed seedlings. The studies suggest that the maintenance of membrane integrity is of paramount importance, and that the hardening treatments might modulate the endogenous levels of H2O2 and ascorbic acid in stressed seedlings which, in turn, might influence membrane integrity.
DIRECT FOLIAR EFFECTS OF SIMULATED ACID RAIN
Authors: HAINES B. L. , JERNSTEDT J. A. , NEUFELD H. S. 
Published: May 2006

SummarySurface characteristics and wettability of the leaves of six plant species have been examined in relation to their susceptibility to damage from simulated acid rain. The species examined differed in the type and extent of epicuticular wax deposits, surface topography of the cuticle, trichome type and distribution, and epidermal cell shape. Leaf wettability, as measured by either water‐holding capacity or droplet contact angle, was significantly different among species, and is highly correlated with previous reports of damage from simulated acid rain. The leaves of Platanus occidentalis L. were the most wettable of the species examined and are reported to be damaged the most by repeated applications of simulated acid rain. Mature leaves of hiriodendron tulipifera L., with high contact angles and very low water‐holding capacity, are the least damaged according to published reports. Leaf water‐holding capacity and surface‐droplet contact angle may be useful first indicators of resistance to acid rain, and should be included m future studies of foliar effects of acid rain.
VESICULAR‐ARBUSCULAR MYCORRHIZAS OF GINKGO BILOBA L. IN NATURAL AND CONTROLLED CONDITIONS
Authors: FONTANA ANNA 
Published: May 2006

SummaryThe morphology of Ginkgo biloba L. vesicular‐arbuscular mycorrhizas (VAM) was investigated in natural conditions and after innoculation with Glomus epigaeum Daniels and Trappe. Morphological features of the infections were similar. The most interesting morphological feature was the presence of abundant intracellular hyphae; intercellular hyphae were rare. Synthesis tests showed the complete Glomus epigaeum life cycle, with the production of sporocarps. Natural infection of Ginkgo biloba roots is considered to be a common phenomenon, and Glomus epigaeum inoculation in controlled conditions increased growth of seedlings.
THE NATURE OF GROWTH DEPRESSIONS IN SUNFLOWER CAUSED BY VESICULAR–ARBUSCULAR MYCORRHIZAL INFECTION
Authors: KOIDE ROGER 
Published: May 2006

SummaryWhen mycorrhizal (M) and non‐mycorrhizal (NM) plants were grown in a soil of low phosphorus (P) availability (5 μg g−1), mycorrhizal infection caused a transient depression in leaf area relative to NM plants that lasted for seven to eight weeks. When plants were grown in this same soil with added P, leaf areas of M and NM plants were similar. When plants were grown in a soil of moderate P availability (15 μg g−1), infection decreased leaf area throughout the experiment.High soil P levels were associated with lower degrees of infection. The degree of infection was positively correlated with the degree of depression of leaf area while the soil P level was negatively correlated with the ability to overcome the initial depression.When M and NM plants were grown in the soils of either low or moderate P availability, the relationship between relative leaf expansion rate (RLER) and tissue P concentration was the same for M and NM plants. Also, mycorrhizal infection did not affect plant N concentration to the same degree as it did P concentration. When grown in the soil of low P availability, dry matter in the shoot was shown to be partitioned differently for M and NM plants. M plants in vested mo re dry matter in leaves relative to stems compared to NM plants. Phosphorus‐amended NM plants also invested more dry matter in leaves relative to stems compared to unamended NM plants. Because of the possible difference in leaf dry weight: stem dry weight ratio between M and NM plants, final harvest shoot dry weights were not an adequate measure of the physiological status of the plants. Leaf expansion was shown to be a good indicator of M effects on plant growth.
RELATIONSHIP BETWEEN DOSE OF SO2 AND NO2 MIXTURES AND GROWTH OF POA PRATENSIS
Authors: WHITMORE MARY E. 
Published: May 2006

SummaryA series of experiments was conducted in controlled environment chambers to investigate the relationship between the concentration of mixtures of SO2 and NO2, length of exposure and growth of the amenity grass Poa pratensis L. cv. Monopoly. Plants were exposed to concentrations of 40, 70 and 100 nl 1−1 SO2 and NO2, in one to one ratio, for periods of 20, 34 and 38 d and compared with controls grown in partially filtered air. The effects of the pollutants on plant dry weight were related to the product of exposure concentration and duration within the limits of the experimental conditions. A dose‐response curve was therefore constructed which illustrated that although small doses may have no effect or may even stimulate growth, slightly larger doses may be severely inhibitory. In order to clarify the effects of small doses a further experiment was performed in which the response was observed at intervals during a 50 d exposure to 40 nl 1−1 SO2 plus 40 nl 1−1 NO2. The results confirmed that low doses could cause small growth stimulations and that the transition from beneficial to inhibitory effects occurs over a narrow range of doses.A subsequent exploratory experiment provided an example of how the environmental conditions during exposure may affect this relationship, and illustrated that each dose‐response curve is only applicable to a given set of conditions.
A HOXNIAN INTERGLACIAL SITE AT ATHELINGTON, SUFFOLK
Authors: COXON P. 
Published: May 2006

SummaryInterglacial deposits lying in a basin in till of Anglian age 7.5 km south east of Hoxne are shown to be of Hoxnian age. The sedimentary record suggests deposition in quiet and flowing water with occasional periods of drying out as the basin filled with sediment. The palaeobotanical record indicates the basin was surrounded by mixed oak forest during the earlier period of deposition and later by a forest dominated by Abies. The depositional environment and the palaeobotanical record at Athelington are similar to those at neighbouring Hoxnian sites.