bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ascomycete mycorrhizas from pot‐grown silver‐fir seedlings (Abies alba Mill.)
Authors: BERNDT R. , KOTTKE I. , OBERWINKLER F. 
Published: April 2006

SUMMARYFour types of ascomycete mycorrhizas were found on seedlings of Abies alba grown in pot cultures on mineral soil. One type was formed by Cenococcum graniforme Ferd. & Winge; the fungal partners of the other three types could not be identified. The macroscopic and microscopic characteristics are described. One mycorrhiza appeared to be identical with Type 15 of Haug & Oberwinkler, found in natural spruce stands. Senescent stages of this type are also described. Ultrastructural investigations showed that the dolipore seemed to be the main distinguishing feature between ascomycete and basidiomycete mycorrhizas. Differences in the matrix of the interface and the fungal wall were not stable enough to be used as a distinguishing feature between asco‐ and basidiomycetes. Dead fungal cells were isolated from the living tissue by plugging of septa with Woronin bodies and walling‐over of the plugged septa. Subsequently these isolated dead cells could be colonized by the fungus. The predominant mycorrhization of the fir seedlings by ascomycetes in pot culture with mineral soil is discussed.
15N natural abundance as a possible marker of the ectomycorrhizal habit of trees in mixed African woodlands
Authors: HÖGBERG PETER 
Published: April 2006

SUMMARYThe partial contribution by fixed nitrogen in N2‐fixing plants can be estimated if the 15N natural abundance of non‐N2‐fixing reference species, which derive their N from the soil, deviates from that of atmospheric N2 (the 15N natural abundance method). Data from Tanzanian miombo woodland showed a significant difference (= 1.0‐2.5 δ15N%0) in 15N abundance between ectomycorrhizal and vesicular‐arbuscular (VA) mycorrhizal reference species. This finding casts doubt upon arbitrary selection of reference species, and also raises the possibility of using 15N abundance as a marker of the ectomycorrhizal habit. It is suggested that the higher 15N abundance of ectomycorrhizal tree species could result from differences in discrimination during uptake or from greater utilization of organic N.
Variation in [75Se]selenate uptake and partitioning among tomato cultivars and wild species
Authors: SHENNAN C. , SCHACHTMAN D. P. , CRAMER G. R. 
Published: April 2006

SUMMARYEight Lycopersicon esculentum cultivars and six wild taxa from four Lycopersicon species were tested for their ability to transport and distribute Se under low and high sulphate salinity conditions. Plants were exposed to [75Se]selenate for 1 h. Significant variation was observed in both morphological and transport characteristics that control the short‐term uptake and accumulation of selenate in tomato species.Among L. esculentum cultivars under low salinity, selenate uptake ranged from 126‐184 pmol g f. wt root−1 h−1 and shoot 75Se concentrations ranged from 40‐66 pmol g f. wt shoot−1. Shoot accumulation was affected by both specific root weight (SRW, root fresh weight/total plant fresh weight) and uptake of the cultivar. Distribution of tracer between root accumulation and transport to the shoot, expressed on a root weight basis, was similar in all cultivars. High sulphate salinity reduced uptake to around 22 pmol g f. wt root−1 h−1 in all cultivars and only small differences in shoot 75Se concentration (7.4‐10.5 pmol g f. wt shoot−1) were observed, indicating that root uptake rate was the primary determinant of shoot 75Se concentration under these conditions. In the low‐salinity treatment wild accessions showed a wider range of uptake rates (52–190 pmol g f. wt root−1 h−1) and shoot Se concentrations (12–79 pmol g f. wt shoot−1) than the cultivars. High sulphate salinity had a less inhibitory effect on Se uptake in the wild taxa than in the cultivars, with uptake rates of 18–63 pmol g f. wt root−1 h−1 and shoot concentrations of 7–28 pmol g f. wt shoot−1 measured. Differences in uptake, partitioning and SRW all contributed to the variation in shoot 75Se uptake in these taxa at both salinity levels.One cultivar (UC82B) was tested under high chloride salinity. Uptake was reduced by 40% relative to the low salt control, compared with the 87% reduction observed under high sulphate salinity. The apparent inhibition in the presence of chloride salinity could be explained by the 40% reduction in selenate activity calculated for this solution relative to the control. Reduced selenate activity was insufficient to account entirely for the reduced uptake observed in this taxon under high sulphate salinity. In contrast, after allowing for reduced selenate activity, uptake by L. pennellii LA716 was little affected by an increase in sulphate from 2.9 and 38 mM, showing that considerable variation in selectivity of the transport system for selenate versus sulphate exists among Lycopersicon species.
The relationship of light and plant geometry to self‐thinning of an aquatic annual herb,Murdannia keisak(Commelinaceae)
Authors: DUNN CHRISTOPHER P. , SHARITZ REBECCA R. 
Published: April 2006

SUMMARYSelf‐thinning was examined in shaded and unshaded populations ofMurdannia keisak(Hask.) Hand.‐Mazz. (Commelinaceae). Four mathematical descriptions of self‐thinning were compared: (1) the traditional – 3/2 thinning rule in which mean plant biomass is regressed on density; (2) principal components regression of mean plant biomass and density; (3) total stand biomass regressed on density, and (4) principal components regression of total stand biomass and density. Most slopes conform to the expected ones; however, confidence intervals reported here and in the literature are wide which may reduce the ecological value of the thinning lineper se.In addition, plants grown in full sun form significantly fewer branches than those in shade. This difference in geometry results in differences in mean plant volume, in plant packing, and thus, in different thinning trajectories.
Stimulatory effects of SO2 on growth of Eucalyptus rudis Endl.
Authors: CLARKE KAREN , MURRAY FRANK 
Published: April 2006

summary Eucalyptus rudis Endl. saplings were exposed to either 274 μg m−3 SO2 or 132 μg m−3 SO2 for 8 h d−1, over 123 d, in open‐top chambers. Exposure to 132μg m−3 SO2 increased the height of the plants and increased the average area and dry weight of leaves. Exposure to 274 μg m−3 SO2 increased the concentration of total sulphur in the leaves and increased the number of leaves abscised. Sulphur accumulation in the leaves decreased as the duration of exposure increased.
A CHECK‐LIST OF MYCORRHIZA IN THE BRITISH FLORA–SECOND ADDENDA AND ERRATA
Authors: HARLEY J. L. , HARLEY E. L. 
Published: April 2006

PreambleThe check‐list of mycorrhiza in the British flora was first published in February 1987 as a supplement of Vol. 105, No. 2 of this journal. A first list of Addenda and Errata, together with an Index, was published in December 1987 in Vol. 107, No. 4, pp. 741–749. This second list of Addenda and Errata is available as a reprint uniform in size with the check‐list to those who subscribed to it, gratis on request to the Executive Editor. Those wishing to obtain the checklist and both addenda may obtain copies by sending a cheque for £8 (sterling only) payable to the New Phytologist Trust, to the Executive Editor, The New Phytologist, Department of Animal and Plant Sciences, The University of Sheffield, Sheffield, S10 2TN, UK, together with an adhesive label addressed to themselves. Requests should not be sent to the authors.The authors wish to reinforce their previous description of this checklist by emphasizing that it is designed to enable scholars to find and study what has been written about the mycorrhiza of species of the British Flora and does not provide detailed information. The authors would gratefully receive information of errors in the list or further information and reprints of papers concerning mycorrhiza in British plants which have not yet been included in this list, where the work was conducted using European material (not material collected outside Europe).
Does calcium in xylem sap regulate stomatal conductance?
Authors: ATKINSON C. J. , MANSFIELD T. A. , DAVIES W. J. 
Published: April 2006

SUMMARYWhole plants and individual leaves of Commelina communis and Triticum aestivum were used to study the influence of changes in apoplastic Ca on the regulation of gas‐exchange, in particular stomatal conductance (g) and transpiration (E). Plants grown in nutrient solution at a low concentration of Ca (1 mol m−3) were used in experiments where rapid changes in Ca concentration were induced via the rhizosphere or by direct entry into the xylem. Solutions containing Ca2+ ions were applied directly to the leaf surface and also through the cut end of detached leaves and via a xylem feeding system to attached leaves. Putative Ca‐channel blockers (lanthanum chloride and verapamil hydrochloride), which are believed to deny Ca entry into the cytoplasm, were also used to provide more information about the nature of the action of Ca on the guard cells.In all the experimental systems used, the short‐term application of 8 mol m−3 Ca induced reductions in both g and E, but when longer‐term changes in the calcium concentrations in the xylem sap were induced through changes in Ca supply from the rhizosphere, no change in g was apparent. These experiments raise important questions about how plants with an abundant supply of calcium in the rhizosphere prevent high concentrations of apoplastic calcium from interfering in the stomatal mechanism. The data presented do not preclude the possibility that a pulse of calcium ions delivered into the xylem could be used in root–shoot communication.
An altered phosphate uptake system in arsenate‐tolerant Holcus lanatus L.
Authors: MEHARG ANDREW A. , MACNAIR MARK R. 
Published: April 2006

SUMMARYThe mechanism of phosphate and arsenate uptake was investigated in arsenate‐tolerant and non‐tolerant genotypes of Holcus lanatus L. It appeared that arsenate and phosphate were taken up by the roots by the same uptake system in both genotypes, although the uptake system had a much greater affinity for phosphate than arsenate. In non‐tolerant plants the uptake of both anions was much greater than for tolerant plants at low phosphate and arsenate concentrations. High‐affinity uptake appeared to be absent in the tolerant plants for both arsenate and phosphate. The absence of this high‐affinity uptake is discussed in terms of arsenate tolerance in this species. The identification of a mutant with only one phosphate uptake system provides further evidence that ‘normal’ uptake of ions occurs via two distinct transport systems. The theoretical and ecological implications of this altered phosphate uptake mechanism are considered.
Utilization of AlPO4 as a phosphorus source by ectomycorrhizal Pinus rigida Mill. seedlings
Authors: CUMMING JONATHAN R. , WEINSTEIN LEONARD H. 
Published: April 2006

SUMMARYMycorrhizal infection of roots of Pinus rigida Mill, seedlings by Pisolithus tinctorius Coker & Couch maintained normal foliar P relations when seedlings were exposed to Al in solution. To investigate how this symbiosis aids in P acquisition in the presence of Al, seedlings were grown in sand culture with solutions containing between 1 and 50 μM NaH2PO4 (Pi) with or without insoluble AlPO4 in the substrate. Mycorrhizal seedlings had a higher affinity for Pi than non‐mycorrhizal seedlings as judged by superior growth and foliar P contents at all Pi levels tested. In addition, mycorrhizal seedlings, but not nonmycorrhizal seedlings, effectively extracted P from AlPO4 through the dissolution of this insoluble salt. Measurement of matrix solution pH indicated that increased proton production, in association with high proliferation of mycorrhizal roots under P‐limiting conditions, led to increased AlPO4 solubilization.
Tansley Review No. 27 The control of carbon partitioning in plants
Authors: WARDLAW IAN F. 
Published: April 2006

SummaryThis review reports on the processes associated with carbon transfer and metabolism in leaves and growing organs and the role of long‐distance transport and vascular links in the regulation of carbon partitioning in plants. Partitioning is clearly influenced by both the supply and demand for photosynthate and is moderated by vascular connections and the storage capacity of the leaves and pathway tissues. However there appears to be little more than circumstantial evidence either that short distance transfer of carbon within either the source or the sink, or that long‐distance transport in the phloem, are limiting photosynthesis or growth directly. Although individual biochemical and physiological processes relating to photosynthesis and growth may be well understood, the factors primarily responsible for the control of carbon partitioning in plants have not been clearly identified. There is a need for a greater understanding of organ initiation and development (source and sink formation and potential size), the clear identification of whether growth is sink or source limited (including possible sink‐controlled photosynthesis) and a detailed assessment of the role of storage in buffering developmental and environmental changes in sink and source activity. Also more information is needed on the role of hormonal and nutritional factors in regulating source and sink activity (organ interactions not directly associated with carbon transfer).CONTENTSSummary341I.Introduction342II.General source‐sink relationships342III.Control at the source345IV.The utilization of photosynthate: sink characteristics and limitations353V.Vascular constraints and temporary storage360VI.Concluding comments366Acknowledgements366References367
The association of Morchella rotunda (Pers.) Boudier with roots of Picea abies (L.) Karst
Authors: BUSCOTAND F. , KOTTKE I. 
Published: April 2006

SUMMARYA histo‐cytological study of Norway spruce [Picea abies (L.) Karst.] roots connected to ascocarps of Morchella rotunda (Pers.) Boudier revealed that hyphae of morel were associated with all parts of the root system. The main suberized roots were surrounded by a mycelial sheath. The finer rootlets were enveloped by a cottony mycelium and their absorbing root tips were found to be ectomycorrhizal. Morel hyphae also invaded the oldest parts of a heterobasidiomycete ectomycorrhiza.
Copper tolerance and copper uptake ofLotus purshianus(Benth.) Clem. & Clem. and its symbioticRhizobium lotiderived from a copper mine waste population
Authors: WU LIN , LIN SHEN‐LIN 
Published: April 2006

SUMMARYLotus purshianus(Benth.) Clem, and Clem., growing on a copper mine waste in Northern California, exhibits copper tolerance. Effective nitrogen fixation (acetylene reduction) is seen in copper‐enriched soils. When subcultured in liquid culture,Rhizobium lotiisolated from root nodules ofL. purshianusgrowing on the copper mine, showed considerably greater copper tolerance than did rhizobium isolated from plants growing in a nearby field. No difference was detected in either the pattern of copper uptake or concentration in plant tissue between tolerant and non‐tolerantL. purshianus.However, a copper accumulation mechanism associated with copper tolerance was found in the symbiotic rhizobium. The successful colonization of copper enriched soil by this legume species is accomplished by the evolution of copper tolerance in both the legume plant and its symbiont. The copper tolerance of the plant and rhizobium may have evolved independently.
Relationship of colonization and sporulation by VA mycorrhizal fungi to plant nutrient and carbohydrate contents*
Authors: DOUDS DAVID D. , SCHENCK N. C. 
Published: April 2006

SUMMARYVesicular‐arbuscular (VA) mycorrhizal fungi typically produce spores either within roots of a host plant or in the soil. Experiments were conducted to examine the effects of plant nutrition, as measured by tissue N, P, K, and soluble sugar concentrations, upon colonization of roots of Paspalum notatum Fliigge and sporulation within roots by Glomus intraradix Schenck & Smith and in the soil by Acaulospora longula Spain & Schenck and Gigaspora margarita Becker & Hall. Plants receiving a balanced nutrient solution without P consistently had the greatest percentage root length colonized by VA mycorrhizal fungi. Glomus intraradix produced more spores per root weight under conditions of nonmycotrophy, when plants received either water only or KH2PO4 only in the nutrient‐poor soil used in these experiments. Gigaspora margarita and A. longula produced more spores in the soil when plants received the balanced nutrient solution without P. Similarly contrasting responses were seen when sporulation inside and outside the roots was correlated to plant nutrient and soluble sugar concentrations. The P‐tolerant, intraradical‐sporulating, VA mycorrhizal fungus G. intraradix sporulated heavily when N: P ratios of host tissue were imbalanced toward P. Acaulospora longula and G. margarita produced more spores in the soil when plant tissue N:P ratios were imbalanced toward N.
Growth of five families of Pinus taeda L during three years of ozone exposure
Authors: ADAMS M. B. , KELLY J. M. , TAYLOR G. E. , EDWARDS N.T. 
Published: April 2006

SUMMARYLoblolly pine (Pinus taeda L.) seedlings of five half‐sib families were grown for 3 yr in the field in open‐top chambers. The seedlings were fumigated during the growing seasons (approximately April‐October) with ozone at the following target levels: subambient (CF), ambient (AMB), and ambient+ 60 ppb (AMB +). At the end of the three growing seasons, no significant ozone effects on diameter, height or total biomass of the seedlings were detected, and no statistically significant ozone‐family interactions were detected. Analysis of growth trends suggest that drought during the second and third growing seasons may have interacted with the ozone treatments. The importance of long‐term studies under realistic field conditions is discussed.
Pollen and related studies at Kinloch, Isle of Rhum, Scotland, with particular reference to possible early human impacts on vegetation
Authors: HIRONS KENNETH R. , EDWARDS KEVIN J. 
Published: April 2006

SUMMARYThe Inner Hebridean island of Rhum lies between the once wooded mainland of north‐west Scotland and the now largely treeless islands of the Outer Hebrides. Rhum is more exposed than the nearby larger islands and is of particular interest since it has been occupied by humans for at least 8500 years. Pollen, charcoal and radiocarbon studies were carried out on a peat profile from Kinloch in the most sheltered eastern part of the island, some 300 m from the site of the earliest known Mesolithic occupation site in Scotland.From an estimated 7800 BP, the local mire surface was open with some hazel and willow scrub. Alder replaced willow at c. 6500 BP and with hazel, remained the dominant woody vegetation until c. 4000 BP when both were reduced and by which time evidence for agriculture is discernible. A period of reduced Alnus and Corylus between 5950 and 5700 BP, with high concentrations of charcoal, may result from human influence. An Alnus reduction dated to between 5250 and 4950 BP may have been caused by changes in mire hydrology. The woodland was more open than that at nearby mainland sites but it was comparable to well‐wooded sites on Skye and Mull. Birch was notably less significant at the Rhum site and the preponderance of Alnus along with persistently high Osmunda values may indicate that adaptation to exposure and salt tolerance were important factors in determining the character of the early postglacial vegetation.
Salinity induced structural changes in meristematic cells of barley roots
Authors: HUANG CHENG X. , van STEVENINCK REINHARD F. M. 
Published: April 2006

summaryStructural changes occurring in meristematic cells of barley (Hordeum vulgare L. cv. California Mariout) in response to moderate salinity treatment were studied. In the apical region of the root, salt caused an increase in vacuolation which may provide a means for accumulation of excess ions. Salt treatment also caused many plastids in the cortical cells in this region to adopt varying amoeboid shapes, often appearing to enclose part of the cytoplasm which was less dense than the surrounding cytoplasm. This suggested that plastid morphology may allow or alternatively result from adaptive changes in protein synthesis or cvtoplasmic composition.
A split‐root experiment shows that iron is required for nodule initiation in Lupinus angustifolius L.
Authors: TANG CAIXIAN , ROBSON ALAN D. , DILWORTH MICHAEL J. 
Published: April 2006

summaryA split‐root system was used to examine the effect of iron on nodule initiation and development in lupins (Lupinus angustifolius L. cy. Yandee) in solution culture. An inoculum of Bradyrhizobium was added to one half of the root system which then received either 0‐05 or 2‐5 μM iron, in various combinations. Where inoculum was present along with a low concentration of iron, the numbers of nodule initials and nodules were markedly decreased, irrespective of whether or not the shoots of the plant were adequately supplied with iron. The limitation to nodule formation was independent of host plant growth. Where half of the roots were given 2–5 μM iron, plants translocated little iron to the roots grown in the other compartment at 0.05 μm iron. Foliar application of iron obviated deficiency symptoms in the shoot but did not increase nodulation. We conclude that, for nodule initiation, iron is required either in the external solution or within the root.
A test of mycorrhizal benefit in an early successional plant community
Authors: GANGE A. C. , BROWN V. K. , FARMER L. M. 
Published: April 2006

summaryThe fungicide ‘Rovral’ (iprodione) was applied in granular form in an attempt to reduce VA mycorrhizal infection of plants during the early stages of secondary plant succession, namely the first year of colonization of bare ground. In 7 out of 11 plant species examined, infection levels were reduced by the fungicide. Four of these also showed reduced cover abundance as a result of fungicide application. Since three were annual forbs, which as a plant life‐history grouping comprised 73 % of the community, total cover of the vegetation (as measured by point quadrats) was significantly reduced by the fungicide. In three species, reduced infection levels did not appear to result in reduced vegetation cover. The reasons for this are discussed in relation to the dependency of plants on mycorrhizal infection. It was found that fewer plant species recruited into communities where iprodione was applied. The implications of these results, in terms of the role that mycorrhizas play in the structuring of early successional plant communities, are discussed.
Nuclear features in infected roots of Ophrys lutea Cav. (Orchidaceæe)
Authors: BARROSO J. , PAIS M. S. 
Published: April 2006

summaryIn mycorrhizas of Ophrys lutea Cav., nuclear hypertrophy occurs in infected cells and in some neighbouring uninfected ones. Hypertrophied nuclei are amoeboid in shape and possess numerous nuclear pores. The increase in nuclear volume is associated with an increase of the number of nucleoli from 1 to 2–4. These nucleoli possess well defined granular and fibrillar components and several vacuoles. Nuclear bodies of different sizes are associated with the nucleoli or lie free in the nucleoplasm near the nuclear envelope. Silver impregnation reveals that both the fibrillar component of the nucleolus and the nuclear bodies are argyrophilic. Some nucleolar‐associated bodies do not react with the silver stain. After regressive staining with EDTA, the chromatin, the nucleolar fibrillar component and the nuclear bodies lying free in the nucleoplasm are bleached. The nuclear bodies may be transient accumulations of ribonucleoproteins migrating into the cytoplasm.