bluuebunny/crossref_metadata_2025_split huggingface dataset:
Changes in Metabolite Levels during Growth of Acer pseudoplatanus (Sycamore) Cells in Batch Suspension Culture
Authors: SHIMIZU TOMIKO , CLIFTON ANNE , KOMAMINE ATSUSHI , FOWLER MICHAEL W. 
Published: April 2006

AbstractMeasurements were made of the levels of key glycolytic intermediates and co‐factors during the growth of Acer pseudoplatanus L. cells in batch culture. Mass action ratios were calculated for the enzymes phosphoglucoseisomerase, phosphofructokinase and pyruvate kinase. The ratio for phosphofructokinase was greatly displaced from equilibrium.Major increases in the level of NADPH and ATP and energy charge were observed in the initial or lag period of culture. The data indicate that the energy generating system of the cells is most active in the lag phase.
The Role of Malate, Oxalate, and Mustard Oil Glucosides in the Evolution of Zinc‐Resistance in Herbage Plants
Authors: MATHYS WERNER 
Published: April 2006

AbstractMalate, oxalate and mustard oils were analysed in zinc‐resistant and zinc‐sensitive ecotypes of Silene cucubalus Wib., Rumex acetosa L., Thlaspi alpestre L. and Agrostis tenuis Sibth. The effect of zinc on the activities of carbonic anhydrase and peroxidase in Siiene cucubalus was tested. Carbonic anhydrase of the zinc‐resistant ecotypes was stimulated by addition in vivo of high amounts of zinc. The high activity of peroxidase in the non‐zinc‐resistant ecotypes after the addition of zinc documented a poisoning of the sensitive plants by zinc. The amount of oxalate differed greatly between ecotypes. There was, however, no direct correlation between zinc‐resistance and oxalate. When applying zinc to the nutrient medium, the synthesis of oxalate was inhibited in zinc‐sensitive, but stimulated in zinc‐resistant ecotypes of Silene cucubalus and Rumex acetosa. In Thlaspi alpestre high concentrations of mustard oil glucosides were found. Zinc‐resistant plants produced twice as much glucosides as sensitive ones. A possible role of mustard oils in zinc‐resistance is discussed. In the content of malate there were great quantitative differences between zinc‐resistant and zinc‐sensitive plants. All zinc‐resistant ecotypes of all the species contained much higher concentrations in their green organs than the sensitive ones. It is assumed that malate is a major factor in the evolution of zinc‐resistance. Malate may act as a complexing agent for zinc within the plasma, whereas oxalate and mustard oils may function as “terminal acceptors” of large amounts of zinc. The role of malate may be extended by a special transport mechanism, by which zinc is eliminated from the plasma into the vacuole.
Internal Leaf Area and Cellular CO2 Resistance: Photosynthetic Implications of Variations with Growth Conditions and Plant Species
Authors: NOBEL PARK S. 
Published: April 2006

AbstractThe influences of illumination, temperature, and soil water potential during development on leaf thickness, mesophyll cell wall area per unit leaf area (Ames/A), and the cellular CO2, resistance expressed on a mesophyll cell wall area basis (rCO2cell,) were examined for Plectranthus parviflorus Henckel. Although the ranges of all three growth conditions caused at least 9‐fold variations in the leaf biomass produced in 4 weeks, only the illumination had a major effect on internal leaf morphology, e.g. the thickness went from 279 to 831 μm and Ames/A from 10.5 to 34.8 as the photosynthetically active radiation was raised from 3 to 53 nEinsteins cm−2 s−1, while rCO2cell remained close to 154 s cm−1. Variations in the growth temperature, soil water potential, and the nutritional status of the plant, affected photosynthesis mainly by changes in rCO2cell.To compare the influence of internal leaf area on photosynthesis for other plants, especially those with low Ames/A values, the maximum rates of CO2 uptake at light saturation and photosynthetically optimal temperatures were also determined for a moss, Mnium ciliare (C. Muell.) Schimp., and two ferns, Adiantum decorum Moore and Alsophila australe R. Br. As Ames/A went from 2.00 for the moss to 3.8, 7.5, 11.7, and 20.8 for the fens, the illumination at light saturation and the maximum rate of photosynthesis both progressively increased. The cellular CO2 resistance, which theoretically might have a lower limit of 20 s cm−1, ranged from 85 to 190 s cm−1.
Enzymatic Activity in Mitochondria from Orobanche
Authors: SINGH PRIKHSHAYAT , KRISHNAN P. S. 
Published: April 2006

AbstractMitochondria from Orobanche were analysed for the activities of aconitate hydratase, isocitrate dehydrogenase, succinate dehydro‐genase, fumarate hydratase, malate dehydrogenase, NADH oxidase, substrate‐cytochrome c oxidoreductases, glutamate dehydrogenase, aminotransferases, ATPase and “malic” enzyme. The specific activities of isocitrate dehydrogenase, NADH oxidase, substrate‐cytochrome c oxidoreductases and glutamate dehydrogenase in the mitochondria) fraction from parasite tissue compared favourably with those reported for most of the mitochondria from growing and storage tissues. Succinate dehydrogenase, fumarate hydratase and aspartate aminotransferase were of intermediate activity, while aconitate hydratase and malate dehydrogenase had rather low activity, and “malic” enzyme had very low activity in comparison with other preparations. The relevance of these findings in relation to mitochondrial metabolism in the parasite is discussed. No evidence was obtained to suggest any basic abnormality in the biochemical properties of the mitochondria from Orobanche centua which may be correlated with its obligatorily parasitic existence.
The Effects of Shoot Water Status on Some Photosynthetic Partial Processes in Sitka Spruce
Authors: BEADLE C. L. , JARVIS P. G. 
Published: April 2006

AbstractClonal cuttings of Picea sitchensis (Bong.) Carr. were grown in a controlled environment and, after completion of shoot extension and maturation, subjected to a drying cycle. Photosynthesis and stomatal conductance were measured in situ using 14CO2 and a porometer, respectively. Shoot water potential was measured with the pressure chamber. Photosystem and carboxylase activities of chloroplast preparations were measured in vitro. A considerable fall in photosynthetic rate occurred at low water potential. This was associated with stomatal closure and a decrease in CO2 transfer or fixation processes in the mesophyll. Little change in activity of photosystem I, photosystem II, and ribulose 1,5‐diphosphate carboxylase was detected during the drying cycle. Any decline in activity of the photosynthetic partial processes in vivo under severe water stress (Ψ < – 30 bar) was probably masked in vitro as a result of rehydration prior to assay.
Antisenescent Activity of Natural Cytokinins
Authors: KUHNLE JUDITH A. , FULLER GLENN , CORSE JOSEPH , MACKEY BRUCE E. 
Published: April 2006

AbstractThe antisenescent activity of naturally occurring cytokinins (bases and ribosides) has been evaluated by measuring chlorophyll retention in detached wheat (Triticum vulgare) leaf segments. 6‐(3‐Methyl‐2‐butenylamino)‐2‐methylthiopurine (ms2ip) was the most active cytokinin followed by 6‐(4‐hydroxy‐3‐methyl‐trans‐2‐butenylamino)purine (tZ). 6‐(4‐Hydroxy‐3‐methyl‐cis‐2‐butenylamino)‐9‐β‐D‐ribofuranosylpurine (cZR), 6‐(4‐hydroxy‐3‐methyl‐trans‐2‐butenylamino)‐2‐methylthio‐9β‐D‐ribofuranosylpurine (MstZR), and 6‐(4‐hydroxy‐3‐methyl‐cis‐2‐butenylamino)‐2‐methylthio‐9‐β‐D‐ribofuroanosylpurine (mscZR) were essentially inactive. 9‐Ribosyl substitution did not affect the activity of tZ, (±)‐6‐(4‐hydroxy‐3‐methylbutylamino)purine (DHZ), or 6‐(3‐methyl‐2‐butenylamino)purine (2ip), but lowered the activity of 6‐(o‐hydroxybenzylamino)purine (OHBA) and 6‐(4‐hydroxy‐3‐methyl‐cis‐2‐butenylamino)purine (cZ). 2‐Methylthio substitution increased the activity of 2ip and DHZ, decreased the activity of tZ, and had no effect on the activity of cZ. The activities of the simultaneously substituted 2‐methylthio‐9‐ribosyl compounds are lower than those of their corresponding unsubstituted or 2‐methylthio substituted bases with the exception of DHZ.Structure‐activity relationships for chlorophyll retention did not parallel many of the relationships found for callus tissue growth stimulation.
Effect of Low Temperature upon Lipid and Fatty Acid Composition of Roots and Leaves of Winter Rape Plants
Authors: SMOLEŃSKA GABRIELA , KUIPER PIETER J. C. 
Published: April 2006

AbstractWhen winter rape plants were transferred from favourable temperature conditions (25/20°C day/night temperature) to 5°C, the frost resistance of the leaves was increased whereas the frost tolerance of the roots remained unaffected. This permitted an analysis of the changes in lipid and fatty acid composition both as related to functioning of the plant at low temperature alone (roots) and as related to adaptation to freezing and functioning at low temperature (leaves). — Transfer of the plants to 5°C lead to an increase in the level of linolenic acid in roots and leaves. This increase was most evident in the phosphatidyl choline and ethanolamine fractions of the leaves, and in the neutral lipids and in an unidentified phospholipid from the roots. It was concluded that upon transfer of the plants to 5°C a general and non‐specific increase in linolenic acid level contributed to functioning of the rape plants at low temperature; and that parallel but minor increases in linolenic acid level of digalactosyl diglyceride, phosphatidyl inositol and the unknown phospholipid in roots and leaves could only contribute to low‐temperature functioning in specific membrane enzyme locations. Combined adaptation of the leaves to freezing tolerance and low‐temperature functioning was correlated with a higher level of phosphatidyl choline and ethanolamine, predominantly esterified with linolenic acid.
Oscillatory Transpiration and CO2 Exchange of Citrus Leaves at the CO2 Compensation Concentration
Authors: BRAVDO BEN‐AMI 
Published: April 2006

AbstractCO2 and H2O vapor exchange were measured by enclosing citrus (Citrus sinensis cv. Sour Orange) leaves in a temperature controlled transparent leaf chamber. Introduction of dry air into the closed circuit gas flow caused cyclic oscillation in CO2 and H2O vapor exchange. It is suggested that oscillation in the CO2 exchange at the CO2 compensation concentration is due to oscillation in non‐stomatal resistance to CO2. Three types of oscillation were observed: 3–6 min (peak to peak) in young leaves, 30 min in mature leaves, and 160 min in old leaves.
Dipeptides and Amino Acids as Nitrogen Sources for the Callus of Atropa belladonna
Authors: SALONEN MAIJA‐LIISA , SIMOLA LIISA KAARINA 
Published: April 2006

AbstractStem callus of Atropa belladonna was grown on media containing seven dipeptides and the corresponding amino acids, given as the only nitrogen sources and in combination with inorganic nitrogen. Of the eight amino acids studied, only alanine and proline were used effectively by the callus. Three dipeptides (glycyl‐alanine, glycyl‐glycine and prolyl‐proline) promoted growth slightly, but none of them was better than inorganic nitrogen (KNO3, 2.5 mM) as the sole nitrogen source. In combination with KNO3 (2.5 mM), these three peptides stimulated growth more than, or at least as much as, KNO3 (5 mM). Growth was better with glycyl‐alanine and glycyl‐glycine (1.25 mM) than with glycine (2.5 mM), which inhibited growth. Arginine, a usually favourable compound, did not give any growth when used as the sole nitrogen source. Leucyl‐tyrosine, prolyl‐hydroxyproline and prolyl‐methionine inhibited growth when given alone or with inorganic nitrogen. In the case of the prolyl peptides the inhibition seemed to be due to the unfavourable effects of methionine and hydroxy‐proline, which were not counteracted by an equimolar concentration of proline. Both leucine and tyrosine were also strongly growth‐retarding.
The Radial and Longitudinal Path of Ion Movement in Roots
Authors: SINGH CHANCHAL , JACOBSON LOUIS 
Published: April 2006

AbstractThe existence of a barrier to lateral outward diffusion of ions from roots was demonstrated quantitatively and by autoradiography. Ions applied to the apical zone were excreted through the basal cut end with no lateral outward diffusion from the central zone. The ions moving through the conducting tissues showed no leakage to the external solution regardless whether the treatment roots came from seedlings grown under low or high salt conditions. However, when dinitrophenol (DNP) was also applied to the central zone in the external salt solution, leakage of apically applied calcium occurred from the conducting tissues. Autoradiographic studies with labeled calcium suggested that the endodermal layer was an effective barrier preventing the lateral outward diffusion of ions. The ions moved longitudinally through the stele. In the stelar tissues the autoradiographic studies failed to detect the presence of any radioactive calcium in the central duct and in the mature xylem vessels, although high concentrations of labeled ions were found in the living cells of the stele, particularly the xylem parenchyma. It is suggested that xylem parenchyma cells may be involved in the longitudinal transport of ions.
Improved Growth of Tissue Cultures of the Onion, Allium cepa
Authors: DUNSTAN D. I. , SHORT K. C. 
Published: April 2006

AbstractA forty‐fold increase in tissue fresh weight has been achieved for Allium cepa stem tissue callus grown on a modified B5 medium with increased ammonium, phosphate and nitrogen levels; and decreased level of 2,4‐dichlorophenoxyacetic acid. Growth was examined on several standard media, using fresh weight, dry weight and cell number as parameters over an 8‐week growth period. Further, tissue grown upon this medium is more friable than on other media. The value of such friable callus for suspension culture initiation and for single cell cloning experiments is discussed.
Uptake and Distribution of Mercury within Higher Plants
Authors: BEAUFORD W. , BARBER J. , BARRINGER A. R. 
Published: April 2006

AbstractThe uptake and distribution of inorganic mercury (HgCl2) within higher plants (Pisum sativum and Mentha spicata) was examined using solution culture and radiotracer techniques. Plants were found to tolerate an external level of 1 mgHg/kg of solution but both physiological and biochemical processes were affected at 5 mgHg/kg and 10 mgHg/kg. The uptake of Hg into plants grown in hydroponic solution was a function of external concentration. Over the concentration range considered the accumulation of Hg in the roots was linear on a log‐log basis although the uptake of the element into the shoots appeared to be two‐phased. The distribution of Hg in plants was asymmetrical with much greater amounts of the element in the roots than the shoots. Although the level of Hg increased generally in plant tissues with increasing external levels, the proportion retained in the roots, relative to the shoots, was constant (approximately 95%). Two binding characteristics of the Hg within plant tissue were detected. A major proportion of Hg was tightly bound, being unaffected by treatment with ethanol and hydrochloric acid. The remaining Hg in the tissue was removed by either water or hydrochloric acid treatment. Cell fractionation indicated that the major binding component of Hg in plant tissues was the cell wall.
The Effect of Ringing on Cytokinin Distribution in Salix baylonica
Authors: VAN STADEN J. , BROWN N. A. C. 
Published: April 2006

AbstractAlthough quantitative differences were observed in the cytokinin content of mature leaves and bark of Salix babylonica it would appear as if these tissues contained the same cytokinin complement. Ringing resulted in a decrease in the level of cytokinins in the leaves and an increase in the bark, both above and below the girdle. In the leaves the decrease was due mainly to a drop in the level of those compounds that co‐chromatographed with the cytokinin glucosides. These compounds were also almost undetectable in the bark above the girdle, where callus was formed. The observed increase in the cytokinin content of the bark above the girdle was due to higher activity in those parts of the chromatograms where zeatin and zeatin riboside occurred. Ringing stimulated the growth of lateral buds below the girdle. These developing buds as well as the bark below the girdle contained very high levels of cytokinins that cochromatographed with zeatin and zeatin riboside.
Induction of Secondary Abscission in Apple Pedicels in vitro
Authors: PIERIK R. L. M. 
Published: April 2006

Abstract In vitro cultivated apple pedicels without a primary abscission layer can form a secondary (adventitious) abscission layer, especially under the influence of auxins.In the apple cv. Cox's Orange Pippin abscission can only be induced by auxins, while the site of the abscission layer, a few millimetres from the basal ends of the pedicels, is fixed and independent of the auxin concentration. The auxin treatment has to last at least 5–6 days to induce abscission, which is not affected by the presence of a flower. A secondary layer does not occur when pedicels are placed inverted on the media. Although abscission occurs both in light and in darkness, it is strongly promoted by light. Abscission is also accelerated by raising the temperature from 9°C to 21–25°C. High concentrations of 2,3,5‐triiodobenzoic acid reduce the percentage of auxin‐induced abscission. Sugar is required, but the presence of macro‐elements is not essential.
Bark Banding of Pinus radiata with Morphactin (IT3456): Influence on Trunk Anatomy Assimilate Transport and Growth
Authors: DOSS ROBERT P. , NEUMANN PETER M. , BACKHAUS RALPH A. , SACHS ROY M. 
Published: April 2006

AbstractA morphactin formulation containing methyl‐2‐chloro‐9‐hydroxyfluorene‐9‐carboxylate as the major component caused abnormal stem growth in Pinus radiata D. Don seedlings when applied as a bark band. The banded region swelled due to increased cell division in the periderm and cambium. The abnormal stem development in treated trees did not cause a localized girdling effect. The morphactin treatment inhibited shoot elongation and root growth. Treated trees exposed to 14CO2 translocated significantly less assimilate to the roots than did control trees although fixation of 14CO2 by the shoots was not reduced. Label from a bark band of 14C‐morphactin was rapidly translocated to the roots indicating that direct inhibition of root growth by the inhibitor probably occurred.
Control of Ethylene Induced Permeability of Plant Cells by a Substituted Benzothiadiazole
Authors: PARUPS E. V. 
Published: April 2006

AbstractThe permeability of bulb tissues of onion (Allium cepa L.), amaryllis (Hippeastrum hybrids), tulip (Tulipa × hybrida) and daffodil (Narcissus tazetta L.) treated with Ethephon and 5‐methyl‐7‐chloro‐4‐ethoxycarbonylmethoxy‐2,1,3‐benzothiadiazole (TH6241), to water and solutions of 1,3‐dimethylurea was determined by the plasmometric methods. Ethylene treatments promoted, while those with TH6241 generally decreased the cell membrane permeability; TH6241 negated the effects of ethylene on cell permeability.
Initiation, Growth and Nuclear Characteristics of Tissue Cultures of Paeonia suffruticosa
Authors: GILDOW F. E. , MITCHELL J. P. 
Published: April 2006

AbstractTissue cultures of the garden paeony, Paeonia suffruticosa have been established using explants of etiolated stems. Callus formation was induced on agar‐solidified media containing ammonium ions or amino acids together with the hormones 2,4‐dichlorophenoxyacetic acid and kinetin, but not on media lacking the reduced nitrogen component. Attempts to induce callus from explants from green plants were completely unsuccessful and were characterized by the production of intense brown colorations, both of the explant and the medium. Subcultured tissue without the added hormones produced roots, both on solid and liquid media.Growth was tested on a range of liquid media, SH/2, SH, SH × 2 and SH—M, containing 1250, 2500, 5000 and 2500 mg/l potassium nitrate. The SH—M medium also contained 1650 mg/l ammonium nitrate. Growth measured as increased fresh weight was best in the SH/2, SH and SH—M media and was curtailed in the SH × 2 medium. Soluble protein content was highest at the lowest nitrogen concentration.A histochemical comparison of tissue grown on the SH/2, SH—M and SH—M lacking hormones showed that the cells in all the cultures remained diploid while differences were established in total nuclear protein, measured using the ninhydrin‐Schiff procedure. Nuclei from SH—M grown cells have a higher protein content than those from the SH/2 medium while cells from the SH—M medium lacking hormones show a further increase in nuclear protein. This raises the question whether this change in nuclear protein is related to the morphogenesis of roots which occurs in this medium.
Effects of Low Root Temperature on Ion Uptake and Ion Translocation in Wheat
Authors: NORDIN ÅSA 
Published: April 2006

AbstractRoots of wheat seedlings (Triticum aestivum L. cv. Weibulls Starke) were cooled (+1°C) for 24 h while the shoots were kept at 25°C. The treatment induced an increased water deficit in the leaves. Fresh weight, dry weight, and the uptake and distribution of potassium and calcium were measured before and after cooling. Growth, measured both as fresh weight and dry weight increase, was reduced during the cold treatment. Afterwards (at 20°C), growth recovered to nearly pre‐stress rates.Analysis of the potassium fluxes in and out of the roots by 86Rb techniques showed that influx, and to a lesser extent efflux, were inhibited at low temperature. The result was a net potassium uptake rate of one‐third that of unstressed plants. After the cooling period the potassium influx increased to the rate of control plants. The potassium efflux increased to one and one‐half times the rate of unstressed wheat so that net uptake was negative. The increase in potassium efflux was explained by a higher permeability of the root cell membranes after cooling. The net uptake of calcium was reduced to one‐third by root cooling. Contrary to potassium uptake, calcium uptake increased under post‐stress conditions, partly due to a low efflux rate.During root cooling there was a redistribution of dry matter from the leaves down towards the lower part of the shoot. Afterwards the original distribution of dry matter was reestablished. The net flow of potassium and calcium followed a similar pattern as dry matter, suggesting a growth‐regulated flow.
The Effect of Canopy Wetting on Plant Water Status, CO2 Fixation, Ion Content and Growth Rate of ‘Baccara’ Roses
Authors: PLAUT Z. , ZIESLIN N. 
Published: April 2006

AbstractThe effect of canopy wetting of rose (Rosa hybrida) plants on transpiration rate, stomatal resistance, plant water potential, ion concentration in leaves, and several growth parameters was investigated. Plants were grown in a greenhouse and their canopies were exposed to wetting cycles during the daytime. Canopy wetting decreased transpiration rate and increased diffusive resistance to water vapor transfer. Plant water potential was only slightly increased by wetting, mainly in the spring.Canopy wetting did not prevent the decrease in CO2 fixation, which took place before midday when plant water potential dropped below – 10 bars during a rise in radiation intensity. The concentrations of Cl− and Ca2+ decreased in wetted leaves, while the concentration of Na+ was increased and other cations were hardly affected. Canopy wetting inhibited growth rate of rose shoots and flower formation, and increased the average flower weight.