bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon and nitrogen economy of four Triticum aestivum cultivars differing in relative growth rate and water use efficiency
Authors: VAN DEN BOOGAARD R. , GOUBITZ S. , VENEKLAAS E. J. , LAMBERS H. 
Published: April 2006

ABSTRACTWe investigated physiological and morphological traits underlying variation in relative growth rate (KGR) among wheat cultivars. Subsequently, we determined whether higher RGR is correlated with higher water demand and lower plant water use efficiency (WUEp). Further, the correlation between water use efficiency and leaf nitrogen concentration was examined. For this purpose we chose lour cultivars contrasting in RGR or WUEp. Gas exchange of shoots and respiration of roots were measured on intact plants over a 24 h period, and total carbon and nitrogen concentrations of all plant parts were determined. The highest RGR was achieved by the cultivars with the highest leaf area ratio. WUEp was strongly dependent on photosynthetic water use efficiency and was highest for the cultivars with the highest rate of photosynthesis, which achieved higher rates of photosynthesis per unit leaf nitrogen. We found no evidence for a functional or genetic link between the physiological traits underlying differences in RGR (specific leaf area and leaf area ratio) and those causing variation in water use efficiency (photosynthetic rate and transpiration rate). These results indicate that, in wheat, it may be possible to select simultaneously for traits associated with a high WUEp and a high RGR.
Effects of nitrogen and phosphorus deficiencies on levels of carbohydrates, respiratory enzymes and metabolites in seedlings of tobacco and their response to exogenous sucrose
Authors: PAUL M. J. , STITT M. 
Published: April 2006

ABSTRACTA simple method of growing plants in agar was exploited to investigate the effect of long‐term nitrogen (N) and phosphorus (P) deficiencies on respiratory metabolism and growth in shoots and roots of Nicotiana tabacum seedlings, and their interaction with exogenously supplied sucrose. Levels of hexose phosphates and 3‐phosphoglyceric acid (3‐PGA) were low in P‐deficient shoots and roots and high in N‐deficient shoots and roots. The ratio of hexose phosphates to 3‐PGA and levels of fructose‐2,6‐bisphosphate were high in P‐deficient plants and low in N‐deficient plants. These data reflect differences in the way metabolism was perturbed, yet both deficiencies were associated with increased root growth relative to shoot growth, starch accumulation in the shoots, and soluble carbohydrate accumulation, especially hexoses, in the roots. Enzymes for sucrose degradation (sucrose synthase, acid and alkaline invertase) and glycolysis (phosphofructokinase, pyrophosphate‐dependent phospho‐fructokinase and pyruvate kinase) remained unaltered or declined in the shoots and roots. The accumulation of hexoses in roots of N‐ and P‐deficient plants may result from maintenance of high invertase activities relative to sucrose synthase and glycolytic enzymes in the roots. The possibility that hexose accumulation may drive preferential root growth osmotically in N and P deficiencies is discussed. The addition of sucrose to roots to further investigate the interaction of carbohydrates with growth and allocation in low N and low P produced clear effects even though endogenous levels of soluble carbohydrate were already high in the nutrient‐deficient plants. In complete nutrition, growth was stimulated, protein content particularly of the roots was increased and there was a preferential increase in activity of sucrose synthase in roots. At low P, enzyme activities in roots were increased, including sucrose synthase, and protein content increased, particularly in the roots, but there was no increase in growth. In N‐deficient plants, exogenous sucrose led to decreased protein, Rubisco and chlorophyll content in shoots, in contrast to the other conditions, and a higher protein content and a general increase of catabolic enzyme activities and growth in the roots.
The effects of enhanced levels of calcium on the gravireaction of sunflower hypocotyls
Authors: BAGSHAW S. L. , CLELAND R. E. 
Published: April 2006

ABSTRACTA current hypothesis states that there is a redistribution of wall calcium from the lower to the upper sides of horizontal shoots during gravireaction, and because calcium stiffens walls, the unequal calcium distribution results in differential wall extensibility on the upper and lower sides, and thus, causes unequal growth. If this hypothesis is valid, then saturating the cell walls with calcium should minimize the effect of calcium redistribution, and thereby inhibit gravicurvature and stiffen the walls. To test this hypothesis, sunflower seedlings were grown on agar containing 0 to 50molm‐3 CaCl2. The wall‐bound calcium content of the tissues increased as the external concentration of CaCl2 increased, and the epidermal layers were saturated with calcium by the 10molm‐3 CaCl2 treatment. Contrary to the predictions from the hypothesis, the vertical growth and the gravicurvature rate of plants grown in 10molm‐3 CaCl2 were actually accelerated, and wall extensibility, as measured by the Instron technique, was unaffected. These results contradict the hypothesis, and provide further evidence that wall‐bound calcium is not involved in the reaction phase of gravicurvature.
Temperature and growth‐induced water potential
Authors: BOYER J. S. 
Published: April 2006

ABSTRACTWhen the steins of dark‐grown soybean [Glycine max (L.) Merr.] seedlings grew rapidly at favorable temperatures in saturating humidities, a water potential of about 0·2 MPa was induced by growth ($pSo‐$pSw, where $pSo is the water potential of the basal nonelongating tissue and $pSw is the water potential of the elongating tissue). If this water potential was caused by high concentrations of solute in the apoplast, as has been proposed, lowering the temperature should have little effect on the potential. On the other hand, if the water potential was caused by apoplast tensions generated by growth, then the tensions should disappear as growth is inhibited by low temperatures. We observed that the growth‐induced water potential became too small to detect when growth was inhibited by temperatures as low as 13—5 °C. The disappearance was observed as a rise in apoplast water potential using a thermocouple psychrometer for intact plants, a rise in cell turgor using a miniature pressure probe and a decrease in apoplast tensions using a pressure chamber. The disappearance was not caused by a loss of solute from the apoplast because the tensions fully accounted for the growth‐induced water potential at all temperatures. The results are consistent with the lack of solute measured directly in the apoplast solutions at high temperatures (Nonami & Boyer 1987). Therefore, it was concluded that little solute was present in the apoplast at any temperature, and the growth‐induced water potential was associated mostly with a tension that moved water from the xylem and into the surrounding cells to meet the demand of cell enlargement.
Rapid and reversible modifications of extension capacity of cell walls in elongating maize leaf tissues responding to root addition and removal of NaCl
Authors: NEUMANN P. M. 
Published: April 2006

ABSTRACTA creep extensiometer technique was used to provide direct evidence that short (20 min) and long‐term (3d) exposures of roots to growth inhibitory levels of salinity (100mol m‐3 NaCl) induce reductions in the irreversible extension capacity of cell walls in the leaf elongation zone of intact maize seedlings (Zea mays L.). The long‐term inhibition of cell wall extension capacity was reversed within 20 min of salt withdrawal from the root medium. Inhibited elongation of leaf epidermal tissues was also reversed after salt removal. The salt‐induced changes in wall extension capacity were detected using in vivo and in vitro assays (shortly after localized freeze/thaw treatment of the basal elongation zone). The rapid reversal of the inhibition of wall extensibility and leaf growth after salt removal from root medium of long‐term salinized plants, suggested that neither deficiencies in growth essential mineral nutrients nor toxic effects of NaCl on plasmamembrane viability were directly involved in the inhibition of leaf growth. There was consistent agreement between the scale, direction and timing of salinity‐induced changes in leaf elongation growth and wall extension capacity. Rapid metabolically regulated changes in the physical properties of growing cell walls, caused by osmotic (or other) effects, appear to be a factor regulating maize leaf growth responses to root salinization.
Stomatal and nonstomatal limitations of photosynthesis in 19 temperate tree species on contrasting sites during wet and dry years
Authors: KUBISKEM M. E. , ABRAMS M. D. 
Published: April 2006

ABSTRACTA unique approach was used to evaluate stomatal and nonstomatal constraints to photosynthesis in 19 naturally occurring, deciduous tree species on xeric, mesic and wetmesic sites in central Pennsylvania, USA, during relatively wet (1990) and dry (1991) growing seasons. All species exhibited significantly decreased stomatal conductance to CO2(gc) in 1991 compared to 1990. The mesic species had drought related decreases in photosynthesis (A) attributed primarily to increased absolute stomatal limitation toA(Lg), whereas in the wet‐mesic species, the absolute mesophyll limitation (Lm) was at least as important asLgin limitingAduring drought. The xeric species maintained relatively highAduring drought despite decreasedgc.In the xeric and mesic species,Lmdecreased andLgincreased during drought due to stomatal closure. From xeric to mesic to wet‐mesic, the relative stomatal limitation (Ig) generally decreased faster, and relative mesophyll limitations toAincreased faster, with increasinggcsuggesting greater photosynthetic capacity (i.e. greater potential maximumA) with increasing drought tolerance rank of species. Few species exhibited a significant drought‐related decrease in photosynthetic capacity. The results of this landscape‐based study indicate that the interaction of stomatal and nonstomatal limitations ofAvary in a manner consistent with species' drought tolerance and site conditions, and that nonstomatal constraints toAin field plants during a moderate, season‐long drought were generally not as severe as reported in controlled studies.
A branch bag technique for simultaneous CO2 enrichment and assimilation measurements on beech (Fagus sylvatica L.)
Authors: DUFRENE E. , PONTAILLER J.‐Y. , SAUGIER B. 
Published: April 2006

ABSTRACTA cheap CO2 enrichment system was designed to perform continuous gas exchange measurements of branches of mature European beech trees (Fagus sylvatica L.). Branches were grown at ambient (350 cm3 m‐3) and elevated CO2 (700cm3 m‐3) during the whole 1992 leafy period. Leaks resulting from airtightness defaults in the system appeared to be low enough to measure accurately net CO2 assimilation and transpiration rates during the day. However, the CO2 exchange rates during the night (respiration) were too low to allow accurate measurements. Elevated CO2 had a great effect on the net assimilation rate of branches via its influence on both the C3 photosynthetic pathway and the shade‐tolerance of beech trees (85% increase). The A/Ca curves showed no acclimation effect to high CO2, both control and enriched branches increasing their net assimilation in the same way. The decrease of net assimilation rates in mature leaves was similar for both control and enriched branches. The pattern of daily transpiration rates remained the same for both control and enriched branches, hence we can assume that there was no visible CO2 effect on stomata.
Action du glycocolle sur le développement in vitro des colonies prothalliennes de Gymnogramme calomelanos, Filicinée Polypodiacée.
Authors: Sossountzov I. 
Published: April 2006

Résumé

Dans les colonies prothalliennes de Gymnogramme calomelanos, le glycocolle (glycine), comme source unique d'azote, augmente le nombre de prothalles filiformes aux dépens du nombre de prothalles cordiformes.
Le nombre moyen d'anthéridies est le même quelle que soit la concentration des milieux cu azote (la prolifération des prothalles n'est possible (qu'entre 0,5 el 10 mM/glycocolle). La sexualité archégoniale est fortement maxima en présence de 5 mM/glycocolle ou davantage. La longueur moyenne des prothalles est faiblement maxima sur les milieux à 5 et à 6 mM. La largeur moyenne varie à mesure qu'augmente la concentration des milieux en glycocolle (trios maximums: au niveau de 0,5 de 3 à 5 et de 8 à 10 mM). La variabilité des moynnes est toujours plus élevée sur les prothalles des cultures normales que sur ceux des cultures aberrantes.
Entre le 1er et le 6e repiquages, la sexualité et les dimension des prothalles cordes demeurent, dans l'ensemble, constantes. Leur variabilité s'atténue.
Comparés a la solution de Knop normale (10.94 mA/azote), les milieux à glycocolle qui assurent une croissance normale des cultures (1,5 à 5 mM) stimulent la prolifération des prothalles filamenteux aux dépens des prothalles cordés, inhibent le développement des anthéridies et des dimensions prothalliennes, mais exaltent la sexualité archégoniale. Il en est de même si la comparaison est faite à concentration en azote égale (cultures aberrantes et normales).
Der Verlauf der endogenen Tagesrhythmik bei photo‐periodisehen Storlieht‐Versuchen mit Soja
Authors: Bünning E. 
Published: April 2006

ZusainmenfassungEs wird bei Soja mit Hilfe der tagesperiodischen Blattbewegungen der Verlauf der endogenen Tagesrbytbmik unter Licht‐Dunkel‐Zyklen untersucht, die denen In Wareings Experimenten entsprechen.Bei den langen Dunkel‐Periodeu zwischen 39–51 Stunden Dauer, die mit Haupt‐Lichtperioden von 6 oder 9 Stunden alternieren, tritt etwa 20 Stunden nach deren Beginn eine Dunkelstarre ein. Die nächste Lichtperiode induziert erneut eine nicht mehr als etwa 30 Stunden andauenide Rhythmik, der dann wieder eine Dunkelstarre folgt.Störlicht von 30 Minuten Dauer hat während der Zeit, in der die Rhythmik läuft, einen relativ geringen Einfluß auf den Zeitpunkt von Hebung und Senkung. Wirkt es aber wäbrend der Dunkelstarre, so bedingl es ebenso wie eine Haupt‐Lichtperiode einen neuen Start der endogenen Tagesrhythmik.Aus diesen Befunden lassen sich die Ergebnisse Wareings über die Wirkung des zu verschiedenen Zeiten der Duukelperiode gebotenen Störlichts erklären.
Maleic Hydrazide and Isonicotinyl Hydrazide as Carbonyl Reagents
Authors: Suzuki Yonezo 
Published: April 2006

Abstract

The effects of maleic hydrazide (MH) and isonicotinyl hydrazide (INH) on the reactions catalyzed by pea cotyledon amine oxidase, carrot root l‐glutamic decarboxylase, and wheat seedling transaminase have been studied.
The activity of amine oxidase is inhibited if it is incubated with MH or INH before the addition of substrate, and it is also dependent on the time of preincubation.
The effect of MH and INH is depressed or prevented by α‐ketoglutarate, pyruvate, pyridoxal phosphate, and pyridoxal but not pyridoxine, reduced glutathione, cysteine, or CuCl2.
MH and INH inhibit the l‐aspartate transamination by wheat mitochondria. They only slightly inhibit the decarboxylation of l‐glutamate by the carrot root enzyme.
The role of MH and INH is discussed as carbonyl reagents in plant metabolism. decarboxylase. Thus, the mechanism by which Mh and INH inhibit action of l‐glutamic decarboxylase is rather complicated and will not be elucidated very soon. The inhibition of aspartate transamination by MH and INH can be interpreted in terms of two processes: the combination of the inhibitors with α‐ketogultarate and pyridoxal phosphate which is a coenzyme of the transaminase. Since transamination is one of the most important reactions in the amino acid metabolism controlling the protein level in living cells, the effect of MH and INH should be noticed as shown above. Kim and Greulach (1963) report that MH and 5‐fluorouracil markedly reduce the content of free amino acids and DNA in Chlorella pyrenoideas; this in interesting in view of the present results concerning the transamination.
The Influence of CO2 Concentration and pH on Two Chlorella Species Grown in Continuous Light
Authors: Nielsen E. Steemann , Willemoes M. 
Published: April 2006

AbstractBoth Chlorella pyrenoidosa and Chlorella vulgaris grow equally well at 20°C aerated with ordinary air or mixtures of air with 5 or 12 per cent CO2 (5 klux continuous light). Whereas C. vulgaris relatively rapidly adapts to a higher CO2 tension, adaptation takes about 24 hours for C. pyrenoidosa.In Chlorella vulgaris pH in the range 3.6–7.6 has no apparent influence on the rate of photosynthesis in experiments having a duration of two hours. This is true both for algae grown aerated by ordinary air and for algae grown with a mixture of 5 per cent CO2 in air. The adaptation time must be short. In Chlorella pyrenoidosa the same is found for algae in ordinary air, whereas an influence of pH is seen in some experiments where the aeration was by 5 per cent CO2 in air.As is to be expected, the rate of photosynthesis in C. pyrenoidosa during the first two hours is very much influenced by the concentration of free CO2. The highest rate is found at the CO2 concentration at which the algae had been growing previously. The influence on the rate of photosynthesis in C. vulgaris is very much less, although in principle the same.The investigation of the corresponding influence on the rate of respiration is complicated by considerable variation from one series to another. In C. vulgaris this is particularly of importance. In C. pyrenoidosa, the highest rate of respiration is generally found at the CO2‐concentration at which the alga had been growing before the experiment.It seems probable that variations between similar series is due to the fact that the algae were grown in continuous light but with dilution with fresh culture medium when the optical density had reached a certain magnitude. Algae grown in this way are neither synchronized nor non‐synchronized.Our thanks are due to the Danish State Research Foundation for financial support.
Effects of Gibberellic Acid on Growth and Parthenocarpy in the Dwarf Telephone Pea
Authors: Bonde Erik K. 
Published: April 2006

AbstractGrowth in height and production of seedless pods wore studied in Dwarf Telephone pea seedlings treated with relatively large amounts of the potassium salt of gibberellic acid applied in solution to leaflets. Such treatment produced a saturation in growth in height with 2 mg or more per plant when the plants were allowed to grow to maturity. Larger amounts caused no inhibitory effects on growth. Maximum growth with 1 mg per plant was attained only if the treated leaflets were left on the plant for about 14 days, at least, but increasing numbers of weekly 10‐mg applications produced no additional growth affects beyond two applications. Increasing age of plants from 10 to 59 days of age at the time of single 10‐mg applications per plant resulted in decreasing final heights.Gibberellic acid caused the formation of seedless pods a number of weeks after application, and deformed flower petals, elongated peduncles, and conspicuously inflated pods were associated with seedlessness. GA was most effective in inducing parthenocarpy when applied to the first true leaves of young seedlings and became progressively less effective with age. A complete absence of seeds in pods formed on the main plant axis was produced by one application of 10 mg GA per plant, while six applications were required for the suppression of seed formation on side branches.
The in vitro Germination of Pollen of Setaria sphacelata
Authors: de Bruyn J. A. 
Published: April 2006

AbstractThe effects of various substances upon germination and tube growth of pollen of Setaria sphacelata were investigated in hanging‐drop culture. Both sucrose (0.6–0.7 M) and boron (1–5 ppm, as borate) are essential for germination. Comparable results were obtained with boric acid, sodium tetraborate and tri‐n‐butyl borate as boron sources, but sodium tetraphenylboron was inhibitory.Good germination and growth were obtained with raffinose and cellobiose, alone or in combination with sucrose (total 0.5 M); 0.25 M rhamnose, lactose and glycerol were without effect, and xylose, galactose and glucose were slightly inhibitory in the presence of 0.25 M sucrose; 0.25 M arabinose, fructose, mannose, sorbose, maltose, mannitol and sorbitol completely inhibited germination, even in the presence of 0.25 M sucrose.IAA and GA (0.01–10 ppm) could not replace or supplement the effects of borate on germination and growth, indicating the pollen to be self‐sufficient in this respect. Riboflavin (0.1–10 ppm) and calcium pantothenate (1–100 ppm) stimulated germination and growth, whereas 0.01–10 ppm of thiamine, pyridoxine, nicotinic acid and ascorbic acid were generally without effect.Although copper sulphate, manganese sulphate, zinc sulphate and ammonium molybdate could not replace boric acid, 1.0 ppm of copper, manganese and zinc stimulated germination and growth in the presence of boron.In no instance were tubes found comparable in length to those required for fertilisation in vivo. It was concluded that the pollen probably requires a complex mixture of substances, including sucrose and borate, before this can be achieved in vitro.
Further Observations on the Inhibition of Prototheca zopfii Growth by 3‐Amino‐l,2,4‐triazole
Authors: Casselton P. J. 
Published: April 2006

AbstractThe concentration of amitrole (3‐amino‐l,2,4‐triazole) causing 50 per cent inhibition of Prototheca zopfii growth is 1.25 mg/100 g at 25°C. This inhibition is not reversed by adenine. 50 per cent inhibition of growth is also caused by 100–120 mg/ 100 g 2‐aminopurine and this inhibition is partially reversed by 40 mg/100 g adenine, the highest adenine concentration tested due to solubility problems. Imidazoleglycerol accumulation occurs in the medium of cells grown in the presence of amitrole.
Active and Passive Components of Sulfate Uptake in Sunflower Plants
Authors: Pettersson Sune 
Published: April 2006

AbstractThe aim of the investigation was to identify components of active and passive ion uptake and transport in roots of plants and to assess their quantitative relations under different external and internal conditions.The uptake of radiosulfate and water by young sunflower plants from complete nutrient solutions labelled with 35S was studied.The metabolism‐linked nature of the sulfate uptake in the root following the passive migration into the apparent free space (AFS) was demonstrated by the addition of sodium. selenate, 2,4‐dinitrophenol, potassium cyanide, and sodium azide to the nutrient solutions.The magnitude of the AFS measured on a root volume basis varied between 14 and 57 per cent depending on the pretreatment of the plants and the sulfate concentration of the nutrient solution. The variations were supposed to be due to different capacity to bind sulfate by exchange‐adsorption within the AFS.The amounts of sulfate in different fractions of the total AFS‐uptake were computed under certain theoretical assumptions.A quantitative connection was proposed between the magnitude of the adsorbed sulfate fraction in the AFS and the rate of active uptake into the symplasm. The exchange‐adsorption probably constitutes the initial stage of active ion uptake. The stimulating effect by water on ion uptake would be an increase of the speed of transporting ions to, from, or along the adsorption sites in the AFS.Experiments conducted at temperatures in the nutrient solution between 5 and 35 C elucidated the multistep nature of ion transport within a root.