bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF NO, NO2 AND CO2 ON NET PHOTOSYNTHESIS, DARK RESPIRATION AND TRANSPIRATION OF POT PLANTS
Authors: SAXE HENRIK 
Published: May 2006

SUMMARYEight cultivars of the pot plants (Ficus elastica ‘Rdobusta’, Ficus benjamina, Hedera helix ‘Anne Marie’, Hedera canariensis‘Montgomery’, Hibiscus rosa‐sinensis‘Red’, Hibiscus rosa‐sinensis‘Moesiana’, Dieffenbachia maculata‘Compacta’ and Nephrolepis exaltata‘Bostoniensis’) most commonly grown in Danish commercial greenhouses were subjected to 4 d exposures to 1 ml 1−1of CO2, 1 ml 1−1 CO2+ 1 μ 1−1 NO, 1 μ 1−1 NO alone and 1 μ 1−1 NO2 alone. Effects on net photosynthesis and dark respiration of aerial parts and effects on whole plant transpiration were observed before, during and after exposures. The measurements were mathematically transformed to double relative values, to indicate the effects of the different gaseous treatments.Carbon dioxide enrichment enhanced net photosynthesis by 40–9 % and subsequent dark respiration by 235 %, while transpiration was reduced. NO reduced photosynthesis (approximately 20 %) and transpiration (the latter at high CO2 only), but did not affect respiration. NO2 rarely had significant effects. All effects of the gaseous treatments on photosynthesis and transpiration were reversible and had independent mechanisms, while effects on respiration were non‐reversible.On the average, 1 μ 1−1 NO was four times more inhibitory to photosynthesis than 1 μ 1−1NO2.Short‐term effects (4 d) on photosynthesis of exposure to CO2+ NO correlated significantly (P < 0.03) with the long‐term effects (four to five months) on dry weight found using the same cultivars in similar treatments.
STOMATAL‐DEPENDENT AND STOMATAL‐INDEPENDENT UPTAKE OF NOx
Authors: SAXE HENRIK 
Published: May 2006

SUMMARYNO2 uptake of eight pot plants (Ficus elastica ‘Robusta’, Ficus benjamina, Hedera helix ‘Anne Marie’, Hedera canariensis ‘Montgomery’, Hibiscus rosa‐sinensis ‘Red’. Hibiscus rosa‐sinensis ‘Moesiana’, Dieffenbachia maculata ‘Compacta’ and Nephrolepis exaltata‘Bostoniensis’) was shown to correlate with transpiration, while NO uptake had no significant dependence on stomatal opening. NO was taken up at a constant rate throughout the light period, while the uptake of NO2 decreased towards the end of the day in the same manner as transpiration. Uptake of NO in the dark was as high as in the light, while uptake of NO2 in the dark was reduced by as much as transpiration.Relative to total pollutant uptake, the toxicity of NO towards photosynthesis is 22 times higher than that of NO2. NO must therefore have a mechanism of toxicity which is different from that of NO2.A sufficiently high dose of NO (4 ml 1−1 for 5 hours) to reduce transpiration (close stomata) decreased photosynthesis less than a lower dose (1 μ1 1 −1 for 12 h). Since total NO uptake was not dependent on stomatal aperture, but stomatal closure reduced the effect of NO on photosynthesis, it is suggested that stomatas regulate the effective NO uptake, i.e. the small fraction of NO uptake that affects photosynthesis. The larger ineffective portion of the uptake is thought to be absorbed on the outer leaf surface.The sensitivity of cultivars or species to NO or NO2 (i.e. effects on photosynthesis and transpiration) did not correlate with the uptake of either pollutant gas.
THE WEATHERING OF SCOTS PINE EPICUTICULAR WAX IN POLLUTED AND CLEAN AIR
Authors: CROSSLEY A. , FOWLER D. 
Published: May 2006

SUMMARYNeedle surfaces of Pinus sylvestris L. were examined at three sites, two in clean air (SO2 < 10 μg m−3) at Saltoun, (altitude 200 m) and Cairngorm (400 m) and one in polluted air (SO2 c 40 μg m−3) at Gorple (300 m). Needles one, two and (where available) three years old were sampled during the period July 1981 to March 1982. Needle longevity was greater at the two clean air sites where 50 % of two year old needles were present compared with only 10% at the polluted site.The physical structure of epicuticular wax was assessed using scanning electron microscopy. The wax tubes shortened, thickened and fused into an amorphous surface ‘crust’ with time. The rate of this‘weathering’ declined logarithmically. A constant (k) was denned as the weathering constant for this process. Values of/? (months−1) differed significantly between sites (Saltoun 0.061 ±0.01, Cairngorm 0.084 + 0.012 and Gorple 0.154±0.013).In addition to faster weathering, needles at the polluted site were heavily contaminated with particulate debris, much of which had the physical characteristics of pulverized fuel ash that is produced by large coal combustion sources. During‘weathering'the surface layer of tubular wax crystals show a marked increase in thickness from ∼ 130 nm for newly exposed needles to 220 nm after 30 months old. No significant inter‐site differences in the rate of change in tube width were noted.
MODERN POLLEN SPECTRA FROM THE WESTERN INTERIOR OF CANADA AND THE INTERPRETATION OF LATE QUATERNARY VEGETATION DEVELOPMENT
Authors: MACDONALD G. M. , RITCHIE J. C. 
Published: May 2006

SUMMARYThe pollen spectra obtained from 127 lake sediment surface samples from the western interior of Canada are examined. Principal components biplots and discriminant analysis are used to investigate the correspondence between modern pollen rain and major vegetation zones in the study area. It is demonstrated that the major vegetation zones in the western interior of Canada can be distinguished on the basis of their modern pollen rain. Principal components biplots and discriminant analysis are also used to compare late Quaternary fossil pollen assemblages from lakes located near the southern and northern periphery of the modern boreal forest with the modern pollen spectra. The results suggest that the late Pleistocene and early Holocene pollen spectra from the southern and northern periphery of the boreal forest lack modern analogues in the western interior of Canada. The northern and southern boundaries of the boreal forest were located north of their modern positions during the mid Holocene. Vegetation developed and responded to mid Holocene climatic change at different rates at the two sites. Modern vegetation conditions were established at both sites between 5000 B.P. to 3000 B.P. Vegetation has remained relatively stable during the last three thousand years.
PARTIAL RECOVERY IN PLASTIDS OF LEMNA AEQUINOCTIALIS WELWITSCH * 1073 TREATED WITH l‐METHIONINE OR l‐CYSTINE
Authors: MONSELISE EDNA BEN‐IZHAK , PORATH DAN , TAL MOSHE , ARZEE TOVA 
Published: May 2006

SUMMARYWhen light‐grown plants of mutant 1073 of Lemna aequinoctialis Welwitsch were grown in a medium containing 31 μl‐cystine, the tubular clusters characteristic of this mutant disappeared in the mature fronds and chloroplasts and mitochondria appeared normal. l‐Methionine (2 μ) effected a similar but less dramatic change. In young fronds, however, 10% of chloroplasts when supplied with l‐cystine, and 50% when supplied with l‐methionine, still contained tubular clusters.When l‐cystine was supplied to young fronds of the wild‐type strain 6746, chloroplasts were normal but contained much larger starch inclusions. Relative growth rates of both strains were improved by addition of l‐cystine or l‐methionine. In mutant fronds they attained values equivalent to wild‐type control. This partial recovery from ultrastructural defects was not matched by a physiological recovery, i.e. plants were still incapable of photosynthesis and ammonium ion uptake, as were mutant plants in control media.Moreover when the partially recovered plants were tested for ammonium ion uptake, in the presence of either l‐methionine or l‐cystine, ammonium ions from plants moved out into the medium during the first 24 h, while increased ammonium uptake was detected with the wild strain.
REVERSAL BY PHENOLIC COMPOUNDS OF ABSCISIC ACID‐INDUCED INHIBITION OF IN VITRO ACTIVITY OF AMYLASE FROM SEEDS OF TRITICUM AESTIVUM L.
Authors: SHARMA SHASHI , SHARMA S. S. , RAI V. K. 
Published: May 2006

SUMMARYEffects of abscisic acid and certain phenolic compounds have been studied, individually and in combination, on in vitro amylase activity from Triticum aestivum L. seeds. ABA suppressed the amylase activity, in vitro, while salicylic acid, cinnamic acid and ferulic acid applied alone promoted it; vanillic acid caused a slight inhibition. Irrespective of their individual effects, all the phenolic compounds studied reverted the inhibitory action of ABA on amylase activity. This behaviour suggests that phenolic compounds could have a role in regulating mobilization of carbohydrates through degradation of starch, and in turn some role in the regulation of seed germination.
THE POTENTIAL FOR EVOLUTION OF SALT (NaCl) TOLERANCE IN SEVEN GRASS SPECIES
Authors: ASHRAF M. , McNEILLY T. , BRADSHAW A. D. 
Published: May 2006

SUMMARYThe seedling root growth of Agrostis stolonifera L., Agrostis capillaris L., Holcus lanatus L., Lolium perenne L., Dactylis glomerata L., Festuca rubra L. and Puccinellia distorts (L.) Parl. was examined after 14 d of immersion in dilute nutrient solutions containing 0, 150, and 250 mol m−3 NaCl. Root growth of all species was significantly reduced by increasing NaCl concentration.Samples of 10000 to 20000 seeds of each species were then screened for ability to root in solution cultures at NaCl concentrations which markedly inhibited root growth in the first experiment. Small numbers of individuals of all species rooted in these solutions and high and low selection lines were established based upon root length values.Adult plants from these high and low selected lines were compared with an unselected sample for ability to root in a range of NaCl concentrations. The high line plants had significantly longer roots than the unselected plants in all species, and than the low selected line in all species except Agrostis capillaris. Low selected plants had significantly longer roots than unselected plants in Holcus lanatus, and Dactylis glomerata.The pattern of response to selection showed no consistent relationship to the known ecology of the species examined, and suggests that variability in salt tolerance is widely present in species, but for other reasons salt tolerance does not always evolve in natural situations.
CUTICLE, CELL WALL ULTRASTRUCTURE AND DISEASE RESISTANCE IN MAIDENHAIR FERN
Authors: ARCHER K. J. , COLE A. L. J. 
Published: May 2006

SUMMARYLight and scanning electron microscopy showed the pinnules of maidenhair fern, Adiantum raddianum var. raddianum (Hoshizaki), possess hydrophobic, crystalline deposits overlying a well developed cuticle on both abaxial and adaxial surfaces. In response to attempted infection by Botrytis cinerea (Pers. ex Fr.), browning, cell wall thickening and papilla formation occurred. Transmission electron microscopy revealed infection pegs are surrounded by electron‐dense papillae forming partial barriers to further colonization.
EFFECTS OF MYCORRHIZAL INFECTION ON PLANT GROWTH, NITROGEN AND PHOSPHORUS NUTRITION IN GLASSHOUSE‐GROWN ALLIUM CEPAL.
Authors: SMITH S. E. , JOHN B. J. ST. , SMITH F. A. , BROMLEY J.‐L. 
Published: May 2006

SUMMARYGrowth and rates of uptake of nitrogen and phosphorus (inflow) in Allium cepa L. were measured in three experiments. Effects of mycorrhizal infection (Glomus mosseae (Nicol. and Gerd.) Gerdemann and Trappe) and N and P fertilization were investigated. The experiments were carried out in a naturally‐lit glasshouse, so that seasonal variations in solar radiation influenced experimental results.In all experiments, a large positive growth response to mycorrhizal infection was observed when soil P was low. However, at high soil P smaller growth responses to infection were observed, as expected. Infection was associated with increased inflow of P, at all levels of soil P, even when non‐mycorrhizal plants grew as well as or better than mycorrhizal plants. Lower P inflow was observed when infection was low and also at low irradiance in both mycorrhizal and non‐mycorrhizal plants. The results show that mycorrhizal fungi increase the rate at which P is absorbed from soil, even under conditions which precluded a positive growth response to infection.In plants grown in spring and summer (two experiments), mycorrhizal infection was also associated with increased N inflow. N inflows in both mycorrhizal and non‐mycorrhizal plants were lower in a third experiment in late winter and mycorrhizal infection had little or no effect on N inflow in this experiment. Increased N supply increased the inflow of N, concentrations of N in plant tissues and plant growth except in plants that were severely P limited, and there was no evidence that mycorrhizal infection alleviated N stress in low N plants.The results are discussed in relation to the environmental factors limiting plant growth, in particular nutrient uptake via and carbohydrate use by the fungal symbiont.
EFFECTS OF PHOTON IRRADIANCE ON THE GROWTH OF SHOOTS AND ROOTS, ON THE RATE OF INITIATION OF MYCORRHIZAL INFECTION AND ON THE GROWTH OF INFECTION UNITS IN TRIFOLIUM SUBTERRANEUM L.
Authors: TESTER M. , SMITH S. E. , SMITH F. A. , WALKER N. A. 
Published: May 2006

SUMMARYThe effects of photon irradiance on the growth of young plants (up to three weeks old) of Trifolium subterraneum L. and on the development of mycorrhizal root systems were studied with plants grown in a soil/sand mixture inoculated with Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe. Total plant growth was lower when photon irradiance was 100 μmol m−2 s−1, compared with 450 μmol m−2 s−1. Fresh weight of shoots was unaffected, but the fresh weight/dry weight ratio was increased at the lower irradiance in shoots, but not in roots. The main effect of decreased irradiance on the growth of the root system was a reduction in the numbers of first‐ and second‐order lateral roots initiated. The average rate of extension of axial and lateral roots was only slightly reduced. The fraction of the root length infected was lower at the lower irradiance, particularly in the first two weeks. Development of infection was analyzed in terms of the role of formation of mycorrhizal entry‐points (A) and the average rate of growth of infection units (B). Reduction in the fraction of the root length infected was found to be due to a reduction in A. B was remarkably constant at the two irradiances and in the different root subsystems. Thus both roots and infection units respond by making fewer units of unaltered rate of growth.
AXENIC SYNTHESIS OF ERICOID MYCORRHIZA IN VACCINIUM ANGUSTIFOLIUM AIT. BY OIDIODENDRON SPECIES
Authors: DALPÉ Y. 
Published: May 2006

SUMMARY Oidiodendron griseum, O. cerealis, O. rhodogenum, O. tenuissimum and O. truncatum were tested for their endophytic ability on axenic seedlings of Vaccinium angustifolium grown on a synthetic nutrient medium. O. griseum, O. rhodogenum and O. cerealis produced typical intracellular hyphal coils characteristic of the ericoid infection. For these three species, the level of infection reached 9 to 21 % of the root cells after 60 d of incubation. O. truncation and O. tenuissimum did not infect the Vaccinium roots but the latter species stunted development of secondary roots and reduced the growth of the seedlings.
EFFECTS OF MONOVALENT AND DIVALENT CATIONS ON PHOSPHATE ABSORPTION BY BEECH MYCORRHIZAS
Authors: STRULLU D. G. , GRELLIER B. , GARREC J. P. , McCREADY C. C. , HARLEY J. L. 
Published: May 2006

SUMMARYThe rate of uptake of phosphate from dilute solutions of KH2PO4 by Fagus mycorrhizas was much increased if calcium or magnesium, as chlorides, was added to the solution but not if sodium or potassium was similarly added. No effect on the partition of phosphate between sheath and core was observed but increased uptake was associated with an increase in number and phosphate content of phosphatic (polyphosphate) granules. The P/Ca ratio of the granules was reduced in the presence of calcium and increased in the presence of magnesium. It is concluded that these divalent cations are incorporated into phosphatic granules and that their effect on phosphate uptake is related to the reduction in the soluble phosphate present in the cells rather than to their effects on the cell membranes.
FLANDRIAN ENVIRONMENTAL HISTORY OF THE ISLE OF MULL, SCOTLAND
Authors: LOWE J. J. , WALKER M. J. C. 
Published: May 2006

SUMMARYFlandrian percentage pollen diagrams are presented from three sites in western and northern Mull, Inner Hebrides, Scotland, and these data are augmented by pollen concentration evidence from one of the sites. In general terms, the pattern of vegetational development is broadly similar to that found in a previous study in the uplands of south‐central Mull. However, differences in detail are apparent in the vegetational history of the northern and western parts of the island, particularly in the representation of Empetrum, Juniperus and Betula pollen in the early Flandrian deposits, and in the frequencies of Alnus and Quercus in the mid‐ and late‐Flandrian pollen records. These pollen‐stratigraphic contrasts between the three sites, and between these profiles and those from the more sheltered south‐central parts of the island can be attributed partly to differences in pollen recruitment processes and partly to variations in degree of exposure to prevailing winds.
TANSLEY REVIEW NO. 5 FRUCTANS AND THE METABOLISM OF SUCROSE IN VASCULAR PLANTS
Authors: POLLOCK C. J. 
Published: May 2006

SUMMARYThe occurrence, structure and metabolism of fructose polymers in tissues of vascular plants are discussed in relation to the metabolism of sucrose. Distinctions are made between long‐term and short‐term storage of such polymers and the regulatory mechanisms which govern accumulation are examined. The roles of various fructosyltransferases in the synthesis of the different fructan structures from sucrose are outlined. The potential selective advantages of the possession of fructan metabolism in different species are assessed with reference to possible roles as cryoprotectants, in osmotic control and as storage carbohydrates whose metabolism can continue at low temperatures (0 to 5°C). It is concluded that the complexity and variety of fructan structures and of the associated enzyme systems has resulted in an incomplete understanding of their physiology and biochemistry, but their significance as an alternative storage polysaccharide in both leaves and storage organs should not be underestimated.

Contents

I.
Introduction

II.
The structure of fructans in vascular plants: variations on a theme
2

III.
The enzymes of fructan synthesis: common elements and sources of structural diversity
5

IV.
The comparative biology of fructan metabolism: diversity in occurrence and function
11

V.
Concluding remarks
19

Acknowledgements
19

References
19
EARLY SENESCENCE OF THE ROOT CORTEX OF AGRICULTURAL GRASSES, AND OF WHEAT FOLLOWING ROOT AMPUTATION OR INFECTION BY THE TAKE‐ALL FUNGUS
Authors: KIRK J. JANE , DEACON J. W. 
Published: May 2006

SUMMARYNuclear fluorescence following acridine orange staining was used to assess patterns and rates of death of the root cortex (RCD) in Lolium perenne L., L.×hybridum Hausskn. and Dactylis glomerata L. grown in pathogen‐free soil in a glasshouse. The pattern of RCD was as previously described for cereals. The rate of RCD differed significantly between grasses and between cultivates of L. pefenne, but in most instances the cortex was anucleate, except for the innermost cell layer next to the endodermis, in 26 to 27 d old regions of seminal root axes. Root impedance caused by a nylon gauze barrier in soil significantly increased the rate of RCD in one tested cultivar of L. perenne.RCD was more rapid in wheat than in grasses. In 8 d old regions of wheat seminal root axes the cortex contained only 54% of the nuclei initially present. Infection of wheat roots by the take‐all fungus, Gaeumannomyces graminis (Sacc.) Arx & Olivier var tritici Walker, caused vascular disruption followed by more rapid RCD than in uninfected roots. Similarly rapid RCD occurred in amputated roots, though in all instances the pattern of RCD was unchanged. The rate of RCD was slower in long than in short lengths of amputated root, perhaps because of remobilization of nutrients from dying cells.Nuclei persisted for at least 10 d in the inner cortex of 2 cm lengths of young roots of wheat, barley and L. perenne buried in soil at 20 °C. The pattern of nuclear deletion from the root pieces was the same as in whole roots, and the rate of RCD was faster in wheat than in barley, as also found for roots attached to plants. All these results demonstrate a consistent pattern of cortical senescence in graminaceous roots and suggest that it is a programmed phenomenon.
RESPONSES OF THREE VESICULAR – ARBUSCULAR MYCORRHIZAL FUNGI AT FOUR SOIL TEMPERATURES AND THEIR EFFECTS ON COTTON GROWTH
Authors: SMITH G. S. , RONCADORI R. W. 
Published: May 2006

SUMMARYThe effects of four soil temperatures on growth of Stoneville 213 cotton (Gossypium hirsutum L.) and root colonization by three vesicular–arbuscular mycorrhizal fungi were tested in soil temperature tanks in the glasshouse. Growth responses in fresh and dry weights of shoots and plant height were linear for noninoculated plants, but nonlinear for plants mycorrhizal with Glomus intraradices Schenck & Smith, Glomus ambisporum Smith & Schenck, or Gigaspora margarita Becker & Hall at soil temperatures of 18, 24, 30 and 36 °C. Total length of root and length of mycorrhizal root were positively correlated and increased as soil temperatures increased. However, total root length was not significantly changed by soil temperature in nonmycorrhizal plants. At 18 °C, shoot and root growth were not improved by mycorrhizas and total root length was actually suppressed by the endophytes. At 24, 30, and 36 °C, mycorrhizas stimulated plant growth. Shoot dry weights were maximum at 30 °C on plants mycorrhizal with G. margarita and G. intraradicvs and at 36 °C on plants inoculated with G. ambisporutn. Percent root colonization by the endophytes was less than 10% at 18 °C and ranged from 57 to 80% at temperatures of 24 °C or higher. All mycorrhizal plants had increased leaf tissue concentrations of P, Cu, Zn, and Mn with concentrations of Cu, Zn, and Mn greatest in plants mycorrhizal with G. ambisporum. The three mycorrhizal fungi generally stimulated plant growth equally well at 24 and 30 °C and G. ambisporum was slightly more effective as a symbiont at 36 °C than either G. intraradices or G. margarita.
NICKEL INDUCED STIMULATION OF GROWTH, HETEROCYST DIFFERENTIATION, 14CO2 UPTAKE AND NITROGENASE ACTIVITY IN NOSTOC MUSCORUM
Authors: Rai L. C. , RAIZADA MEENA 
Published: May 2006

SUMMARYAddition of nickel stimulates growth, heterocyst differentiation, 14CO2 uptake and nitrogenase activity in Nostnc muscorum. The significance of this observation is discussed.
CARBON NUTRITION AND THE REGULATION OF UPTAKE HYDROGENASE ACTIVITY IN FREE‐LIVING AND SYMBIOTIC ANABAENA CYCADEAE
Authors: KUMAR A. P. , PERRAJU B. T. V. V. , SINGH H. N. 
Published: May 2006

SUMMARY Anabaena cycadeae was grown with N2 as nitrogen source, either photoautotrophically in light or with glucose as carbon source in darkness. The rate of growth was much slower in darkness but the heterocyst frequency was much the same; nitrogenase activity (on a chlorophyll basis) was about half that of light‐grown cells. Light‐grown organisms contained uptake hydrogenase activity but dark‐grown organisms did not. The addition of glucose to light‐grown organisms was followed by the disappearance of uptake hydrogenase activity over the following 48 hours and the disappearance was independent of light. Heterocyst frequency and nitrogenase activity were much less affected by glucose addition. A. cycadeae growing symbiotically in cycad roots had much higher heterocyst frequency and nitrogenase activity than the free‐living form but no detectable uptake hydrogenase activity.It is suggested that the rate of supply of carbohydrate to the heterocyst controls the development of uptake hydrogenase activity and that the absence of this activity in the symbiotic cyanobacteria indicates that the organisms in the cycad roots have an ample supply of carbohydrate.