bluuebunny/crossref_metadata_2025_split huggingface dataset:
ANTIGENIC ANALYSIS OF ANABAENA AZOLLAE AND THE ROLE OF LECTIN IN THE AZOLLA–ANABAENA SYMBIOSIS
Authors: LADHA J. K. , WATANABE I. 
Published: May 2006

SummaryAntigenic cross‐reactivity between symbiotic Anabaena azollae and its Azolla host was detected by an indirect immunofluorescence technique. Antiserum against Anabaena‐free Azolla cell extract cross‐reacted with A. azollae freshly separated from different species of Azolla, but did not cross‐react with any of the free‐living Anabaena species tested, including A. azollae (Newton), which was claimed to be isolated from Azolla.Cell extracts of the whole Azolla‐Anabaena symbiosis and of Anabaena‐free Azolla plants both caused agglutination of human and rabbit erythrocytes whereas extracts of symbiotic A. azollae freshly separated from Azolla plants or free‐living A. azollae (Newton) did not cause haemag‐glutination. Of the several sugars tested α‐D‐galactose inhibited the haemagglutination. Free‐living A. azollae (Newton) showed no cross‐reaction at any growth phase of its life cycle with antiserum against Anabaena‐iree Azolla nor could it bind the haemagglutinating factor from the Azolla‐Anabaena symbiosis.The possible significance of common antigens and lectin in the Azolla‐Anabaena symbiosis is discussed.
DISTRIBUTION OF NITRATE REDUCTASE ACTIVITY IN SIX LEGUMES: THE IMPORTANCE OF THE STEM
Authors: ANDREWS M. , SUTHERLAND J. M. , THOMAS R. J. , SPRENT J. I. 
Published: May 2006

SummaryNitrate reductase activity (NRA) was measured in leaves, stems and roots of six grain legumes supplied with different nitrate concentrations. The contribution of the stem relative to total plant activity was assessed.In Lupinus angustifolius L., Pisum sativum L. and Viciafaba L., legumes of temperate origin, an increased proportion of total plant NRA occurred in the shoot as nitrate concentration was increased. In Cajanus cajan (L.) Wilisp., Glycine max (L.) Merr. and Phaseolus vulgaris L., legumes of tropical origin, the proportion of total plant NRA in root and shoot was relatively constant regardless of nitrate concentration.More than 20% of total plant NRA can occur in the stem of G. max, L. angustifolius, Pisum sativum, Phaseolus vulgaris and V. faba. In C. cajan 10 to 15% of total plant NRA was found in the stem at all nitrate concentrations. It is concluded that stem tissues can contribute significantly to overall nitrate metabolism.
NEW NODULATING LEGUME TREES FROM SOUTH‐EAST BRAZIL
Authors: de FARIA S. M. , FRANCO A. A. , de JESUS R. M. , MENANDRO M. de S. , BAITELLO J. B. , MUCCI E. S. F. , DöBEREINER J. , SPRENT J. I. 
Published: May 2006

SummaryAn extensive search for active (acetylene reducing) nitrogen‐fixing root nodules was made amongst Brazilian forest legumes. Seven new nodulated species, including two new nodulating genera, were found in the Caesalpinioideae, 18 new species in the Mimosoideae and 30 new‐species, including four new genera, in the Papilionoideae. All have potential importance in reafforestation. Fifty‐eight new records of non‐nodulating species are included. The morphology of all nodules was studied and is discussed in relation to taxonomic position. Preliminary data on nodule structure are given.
ULTRASTRUCTURAL ASPECTS OF ENDOMYCORRHIZA IN THE ERICACEAE
Authors: BONFANTE‐FASOLO P. , GIANINAZZI‐PEARSON V. , MARTINENGO L. 
Published: May 2006

SummaryThe development of Pezizella ericae Read in living roots of host plants is typically limited to cells surrounding the central cylinder and the biotrophic phase of host‐fungus interactions is characterized by a highly compatible relationship between the symbionts at the cellular level. In non‐host plants, the ericoid endophyte extensively colonizes root tissues, including the central cylinder, without forming hyphal coils and a necrotrophic relationship occurs at the cellular level, the fungus provoking a rapid degeneration of the contents of plant cells. A fundamental difference between the interactions occurring in cells of host and non‐host roots is the constant presence of the plant plasmalemma surrounding P. ericae in the former and the complete lack of this membrane around hyphae in the latter. External hyphae of P. ericae develop an abundant fibrillar sheath in the presence of both host and non‐host roots. This disappears with hyphal development in living host cells but it persists around intracellular hyphae in non‐host tissues. These observations are discussed in relation to fungus‐plant recognition phenomena and the control of infection in ericoid mycorrhizas.
CHARACTERIZATION OF THE DIFFERENT FORMS OF PHOSPHORUS IN THE MYCELIUM OF THE ECTOMYCORRHIZAL FUNGUS, HEBELOMA CYLINDROSPORUM, CULTIVATED IN PURE CULTURE
Authors: ROLIN D. , LE TACON F. , LARHER F. 
Published: May 2006

SummaryThe ectomycorrhizal fungus, Hebeloma cylindrosporum, was grown in pure culture at different phosphorus concentrations, with or without shaking. Phosphorus fractions were separated by a modified Mudd, Yoshida & Koite (1958) method. Acid‐soluble and acid‐insoluble phosphorus precipitated with barium acetate were identified by thin layer chromatography.In pure culture. Hebeloma cylindrosporum stores very little polyphosphate (4 to 9% of total P) and amounts are unrelated to the concentration of external phosphorus. Most of the phosphorus is stored as orthophosphate. Internal orthophosphate is well correlated with external orthophosphate and is readily utilized to form DNA and phospholipid. Internal soluble organic phosphorus can also be mobilized but to a lesser extent.
CARBOHYDRATE METABOLISM IN THE FUNGUS DENDRYPHIELLA SALINA
Authors: JENNINGS D. H. , THORNTON J. D. 
Published: May 2006

SummaryWhen mycelium of Dendryphiella salina Nicot & Pugh is exposed for 5 h to media containing various concentrations of the very slowly metabolized sugar, L‐sorbose, the total ethanol‐soluble carbohydrate content increases and there is also a stimulated synthesis of mannitol. Provided L‐sorbose is absorbed, the presence of glucose, fructose, mannitol or arabitol in the medium does not prevent these changes which are different from those brought about by the non‐metabolizable sugar, 3‐O‐methyl glucose. It is suggested that the apparent regulation of mycelial ethanol‐soluble carbohydrate concentration following uptake of the latter sugar cannot be controlled primarily by turgor.
KINETIC STUDIES ON THE TRANSPORT OF 2‐OXOGLUTARATE ANDL‐MALATE INTO ISOLATED PEA CHLOROPLASTS
Authors: PROUDLOVE M. O. , THURAMN D. A. , SALISBURY J. 
Published: May 2006

SummaryThe transport of 2‐oxoglutarate and l‐malate into the sucrose impermeable space of pea chloroplasts has been studied by silicone oil centrifugal filtration. The inhibition of transport of these dicarboxylates has been shown to be markedly different in the presence of the alternative dicarboxylate. The suggestion is made that at least two carriers are involved in the transport of 2‐oxoglutarate with similar Km values of 0–20 mm for this substrate. l‐Malate inhibited 2‐oxoglutarate transport with a pseudo Ki value of 0–76 mm. l‐Malate uptake was found to have a Km value of 0–29 mM and its uptake appeared to be inhibited, mainly competitively, by 2‐xoglutarate with a Ki value of 0–2 mm.
SIZE AND ACTIVITY OF QUIESCENT CENTRES OF ROOTS
Authors: CLOWES F. A. L. 
Published: May 2006

SummaryThe quiescent centres of angiosperm roots of a wide range of size and architecture have been investigated by autoradiography and stathmokinetic measurements. The volume and number of constituent cells of the quiescent centre vary with the width of the root, but roots of the Gramineae and Cyperaceae have larger quiescent centres for their size than all other plants except Pistia. The difference is not correlated with the open or closed nature of the meristem nor whether the epidermis is derived from the cortex or cap, but is correlated with a thickened boundary between the cap and the rest of the apex or, in Pistia, ith a discrete epidermal meristem. The number of cells in the quiescent centre approaches zero in the non‐grass type of apex as the width of the root becomes smaller and nearer that of pteridophyte roots with tetrahedral apical cells. The ratio of rates of cell cycling in the quiescent centre to those in the surrounding meristem also varies with root width, but here all closed meristems show greater differences in rates than all open meristems. The ratio comes near to unity in the smallest open meristems. The data are discussed in relation to the reasons for quiescence, the differences between root and shoot meristems and our ability to perform certain surgical operations.
ANATOMICAL FEATURES OF THE SEED COAT OF ACACIA KEMPEANA (MUELLER) WHICH RELATE TO INCREASED GERMINATION RATE INDUCED BY HEAT TREATMENT
Authors: HANNA P. J. 
Published: May 2006

AbstractEntry of water and subsequent germination of hard seeds of Acacia kempeana occurs after the strophiole lifts and cracks. The ‘opening’ of a strophiole is induced by heat and is effected through the splitting of thin‐walled cells lying beneath short palisade cells within the strophiole. Estimated pressure increases of greater than 25 % within the vascular bundle, which passes directly under the thin‐walled cells, might influence strophiolar lifting. The vascular bundle between the hilum and the adjacent strophiole is virtually devoid of xylern vessels, thereby preventing water entry through the hilum. However, following the strophiole, the vascular bundle obtains a maximum number of about 35 xylern vessels and is itself enclosed in this region by a noticeable group of over 150 thin‐walled cells. Many of these thin‐walled cells appear crushed along the route of the vascular bundle through the mesophyll layer to the end opposite the hilum. At the non‐hilum end, the vascular bundle almost touches the internal side of the seed coat and thus entry of water would be facilitated through this zone to the internal endosperm and embryo.
THE QUANTITATIVE STUDY OF MYCORRHIZAL INFECTION
Authors: WALKER N.A. , SMITH S. E. 
Published: May 2006

SummaryThe processes of infection of roots of Trifolium subterr aneum by vesicular–arbuscular mycorrhizas are analysed using a modification of a model presented previously. The modified model uses as dependent variables the fraction of the root length infected and the linear density of infection units. It allows the evaluation of the rate of initiation of new infection units and of the rate of growth of hyphae within the root as functions of time.The model is applied to data for T. subterraneum grown in a 20‐foid range of densities of randomly‐mixed propagules in soil; we show the rate of initiation of new infection units in both main and lateral roots was proportional to the propagule density over short periods (5 to 11 day). However, the rate of initiation of infection units in main roots during this period was approximately half that in lateral roots. The rate of growth of hyphae in the root did not depend on the propagule density.As the main roots ceased to grow, both rates of infection and of mycelial growth fell: these rates did not fall for lateral roots during the 26 days of the experiment. The results raise the question of the dependence of mycelial growth‐rate on the age of the infection unit, which is discussed.The model predicts that the fraction of the root length infected approaches asymptotically a value less than one, as has been repeatedly observed. Other models require arbitrary modification to accommodate such findings.
ANION ACCUMULATION BY LICHENS I. THE CHARACTERISTICS AND KINETICS OF ARSENATE UPTAKE BY UMBILICARIA MUHLENBERGII
Authors: RICHARDSON D. H. S. , NIEBGER E. , LAVOIE P. , PADOVAN D. 
Published: May 2006

SummaryArsenate was accumulated by discs of the lichen Umbilicaria muhlenbergii (Ach.) Tuck, to levels of 16/wnol As per gram oven‐dry weight during 1 h incubation in solutions containing 40μmol of arsenate at pH 4–6. Studies at lower external concentrations and at different pH values revealed that the more protonated species of arsenate were absorbed most readily. Light enhanced arsenate uptake only marginally, which supports the interpretation that the bulk of uptake was by the non‐photosynthetic fungal symbiont. Dinitrophenol caused a 30% reduction in uptake, while heat‐killing lichen samples resulted in negligible absorption, even from solutions of high arsenate concentration. The kinetics of arsenate uptake were studied using the Michaelis‐Menten treatment, and yielded an apparent value for Km of 360 ± 60 μ and a Vmax of 0.37 ± 0.03 μmol g−1 min−1 for H2AsO−4. Fürther analysis by means of the Hofstee and Lineweaver‐Burk plots suggested that two uptake systems may exist. The above results are discussed in relation to published data on free‐living fungi and algae and it is concluded that arsenate uptake provides a convenient means for investigating anion accumulation in lichens.
THE EFFECTS OF MAGNESIUM, NICKEL, CALCIUM AND MICRONUTRIENTS ON THE ROOT SURFACE PHOSPHATASE ACTIVITY OF A SERPENTINE AND NON‐S ERPENTINE C LONE OF FESTUCA RUBRA L.
Authors: JOHNSTON W. R. , PROCTOR J. 
Published: May 2006

SummaryRoot surface phosphatases of a serpentine and non‐serpentine clone of Festuca rubra were assayed under a range of ionic concentrations based on those found in the soil solutions of the extremely toxic Meikle Kilrannoch serpentine. The phosphatases from the serpentine clone showed greatest activity in a solution similar to that in the soil and which had high concentrations of magnesium and nickel. The phosphatases from the non‐serpentine clone were partially inhibited in the same solution. Changes in calcium and concentrations of micronutrients produced no significantly different responses between the clones in phosphatase activity. The results contrast with those obtained by previous workers on a serpentine and imply subtle enzymic adaptations leading to a requirement for simultaneously high concentrations of the potentially toxic ions, for high phosphatase activity. The ecological significance of the adapted phosphatases is unclear.
SEEDS PER FRUIT AS A FUNCTION OF FRUITS PER PLANT IN ‘DEPAUPERATE’ ANNUALS AND BIENNIALS
Authors: KELLY D. 
Published: May 2006

SummaryReproduction was examined in one summer annual (Euphrasia pseudokerneri) and two biennials (Linum catharticum and Gentianella amarella) in chalk grassland, and three dune winter annuals (Erophila verna, Cerastium semidecandrum and Myosotis ramosissima). Gentianella was examined in 1979 to 1981 and all other species in 1980 and 1981, making a total of 13 separate datasets. Plants with one or two fruits had fewer seeds per fruit in all 13 cases. As plant size increased to six to ten fruits, seed number gradually increased. The relationship was similar in 1980 and 1981 for all six species. A ‘depauperate’ plant was therefore denned as one which produces significantly fewer seeds per fruit than large plants. Field populations of all species averaged less than nine fruits per plant, so that the relationship between seed number and fruit number was important in determining seeds produced per plant. Although this relationship has only been noted in three other species, I interpret five recent papers as suggesting the existence of a similar relationship between fruit number and seed number. I interpret the effect as analogous to the abortion of fruits in plants with many fruits.
SMALL‐SCALE DYNAMICS IN AN EARLY HOLOCENE WET SCLEROPHYLL FOREST IN TASMANIA
Authors: MACPHAIL M. K. 
Published: May 2006

SummaryPollen analysis of organic sediments in a small hollow at Tarraleah in central Southern Tasmania allows identification of some small‐scale patterns and processes withinEucalyptuswet sclerophyll forest during the early to middle Holocene. These events are related to a time scale of inferred ages (i.a.), based on three radiocarbon dates and stratigraphic constraints.Although relatively few tree and tall shrub taxa are involved, changes in relative abundance show that at least five floristically distinctive communities of understorey mesophytes have surrounded the hollow. Prior to i.a, 9125 B.P., subalpineEucalyptusopen forest or woodland formed the local vegetation:Pomaderris apetala– Compositae i.a. 8900 to 8325 B.P.Atherosperma moschatum – Dicksonia antarcticai.a. 8175 to 7775b.p.Phyllocladus aspleniifolius – (?)Nothofagus cunninghamiii.a. 7625 to 7350b.p.Pomaderris apetala– sclerophyll shrubs i.a. 7200 to 6925b.p.Dicksonia antarcticaafter i.a. 6925b.p.In most general terms the forest and mire species have behaved consistently with their modern ecological preferences and established trends in Holocene climate. With more detailed resolution, the influence of climate is less apparent and the shifts in community composition more likely to be due to fire frequency and edaphic effects. The results confirm the modern observation that canopy eucalypts and understorey species are only weakly correlated in the presence of fire. Fire has resulted in the separation ofPomaderris apetalacommunities into two ecological entities but in the absence of fire ‐ and fire‐promoting climates ‐ during the early Holocene,P. apetalaand associated mesophytic small trees may have been able to exclude competitively the canopy eucalypts. Similarly the data indicate early Holocene rainforests may have been enriched withA. moschatum.The marked increase in fire frequency at or after i.a. 6925b.p.is suggested to be due to migration into or increased utilization of the area by Aborigines.
PHOTOCONTROL OF SPORE GERMINATION IN POLYPODIUM VULGARE L.
Authors: AGNEW NORMA , McCABE ANNE , SMITH D. L. 
Published: May 2006

SummarySpore germination in the. fern Polypodium vulgare is induced by light at all wavelengths from blue to far‐red, although red light is most effective. The action spectrum for germination together with observations on the photoreversible effects of red and far‐red light provide evidence for the involvement of phytochrome, but the effects of blue light, particularly its interactions with red light, are incompatible with an interpretation in terms of phytochrome alone. It is suggested that two pigments are involved, phytochrome and a blue light absorbing pigment, but that not all spores contain effective levels of both pigments.
BIOLOGICAL EFFECTS OF SURFACTANTS VII GROWTH AND DEVELOPMENT OF BRASSOCATTLEYA (ORCHIDACEAE) SEEDLINGS
Authors: ERNST R. , ARDITTI J 
Published: May 2006

SummaryPhytotoxicity of a homologous series of sulphoberaine surfactants, 3‐(alkyldimethyl‐ammonio)‐1‐propanesulphonates, on Brassocattleya orchids increased with increasing alkyl chain length from eight to 14 carbon atoms of the lipophile, levelled off and then declined with the 18 carbon derivative. Because of its high Krafft point the tatter had reduced solubility at the assay temperature. Interfacial tensions of the nutrient solutions, measured against a test lipid, declined m parallel with the observed phytotoxicity. This and previous findings strongly support the suggestion that disruption of cellular membranes by surface active agents plays a key role in their toxicity.
CHANGES IN THE PHOSPHORUS COMPOSITION OF SEEDS OFHAKEA SERICEA(PROTEACEAE) DURING GERMINATION UNDER LOW PHOSPHORUS CONDITIONS
Authors: MITCHELL D. T. , ALLSOPP N. 
Published: May 2006

SummarySeeds ofHakea sericeaSchrad belonging to the subfamily Grevilleoideae of the Proteaceae greater P reserves than those belonging to the Proteoideae indigenous to South Africa. The main P‐containing compounds in seeds ofH. sericeaare phytic acid with smaller proportions consisting of lipid‐P, RNA, DNA, protein‐P, polyphosphate and orthophosphateHakea sericeagrew on sterile acid washed sand for up to 125 d after sowing before signs of mineral deficiency symptoms appeared. Proteoid roots were produced by seedlings grown in Clovelly sand from 60 d after sowing and their numbers appeared to be related to the accumulation of P in the seedling. It is concluded that the P reserves of seeds ofH. sericeamay provide a competitive advantage over those of the Proteoideae for establishment and growth in the acidic sandy soils of the south‐western Cape, South Africa.
ECOPHYSIOLOGICAL STUDIES OF THE LICHEN, PARMELIA PRAESIGNIS Nyl.
Authors: LINK S. O. , NASH T. H. 
Published: May 2006

SummaryLosses in photosynthetic ability were observed in the lichen, Parmelia praesignis Nyl., over a 2‐week period under three out of four different combinations of temperature and hydration conditions during storage. At a constant daytime temperature of 16 °C, lichens which were wetted even, few days retained more photosynthetic ability than did lichens wetted everyday. Lichens which were maintained under a varying range of temperatures (12 to 26 °C) retained most of their photosynthetic ability, with the material wetted daily eventually losing 40% of its ability. The material wetted every few days did not lose a significant amount of photosynthetic ability. Lichen material maintained at a temperature of 33 °C and wetted everyday lost all photosynthetic ability after 3 d.Photosynthetic ability was found to be normally distributed with a mean of 3.2 mg CO2 g−1 and a standard deviation of 0.65 mg CO2 g−1 h−1 when based on the experimental results from 25 randomly selected sets of thallus tips.
AMINES IN BARLEY LAVES INFECTED BY BROWN RUST AND THEIR POSSIBLE RELEVANCE TO FORMATION OF ‘GREEN ISLANDS’
Authors: GREENLAND A. J. , LEWIS D. H. 
Published: May 2006

SummaryFree amines, present in healthy leaves of barley and in leaves infected by brown rust (Puccinia hordei Otth.), have been partially characterized. The concentrations of five amines present in both kinds of tissue rise following infection and at least three extra amines are detectable in rusted tissue. The concentration of the polyamine, spermidine, increases rapidly by 6 d after inoculation and, at sporulation, it is six to seven times that in comparable healthy tissues. The possible involvement of polyamines in the ‘green island’ syndrome is discussed.
DISTRIBUTION OF CLONES OF GALIUM BOREALE L. ON WIDDYBANK FELL, TEESDALE
Authors: DALE A. , ELKINGTON T. T. 
Published: May 2006

SummaryTwenty‐one clones of Galium boreale L. have been provisionally identified in a grassland area 55 × 30 m on Widdybank Fell, Teesdale, Co. Durham, by comparison of plant samples collected in 25 cm quadrats and grown under cultivation. The species composition of each quadrat was also listed. Quadrat data were analysed by association analysis and a comparison of clonal distribution and major vegetational types made. The results are discussed in relation to the rate of recruitment of individuals and the ecology of G. boreale.