bluuebunny/crossref_metadata_2025_split huggingface dataset:
Internode length in Pisum. Biochemical expression of the le gene in darkness
Authors: Ross John J. , Reid James B. 
Published: May 2006

Ross, J. J. and Reid, J. B. 1989. Internode length in Pisum. Biochemical expression of the Le gene in darkness.The Le gene appears to be biochemically expressed in dark‐grown pea (Pisum sativum L.) plants since the previously reported difference in metabolism of [3H]‐GA30 between light‐grown Le and Le plants was also observed in darkness. Furthermore, both light‐ and dark‐grown Le plants contained more endogenous GA1, ‐like substance than did comparable Le plants. Darkness did not appear to significantly increase the accumulation of GA1, in either Le or Le plants, although confirmation of GA1 levels by gas chromatography‐selected ion monitoring is still required. The results support previous findings that the overall metabolism of [3H]‐GA20, is accelerated by darkness. The evidence presented here supports previous suggestions that darkness acts on internode length by increasing some aspect of GA sensitivity.
Time‐course of uptake of dissolved inorganic carbon through willow roots in light and in darkness
Authors: Vuorinen A. Helena , Vapaavuori Elina M. , Lapinjoki Seppo 
Published: May 2006

Uptake of dissolved inorganic carbon (DIC) from a nutrient solution by willow roots was measured in light and darkness and the distribution in the plant of DIC taken up by the roots was determined. It was also studied whether the transport system could be activated by preincubation with dissolved inorganic carbon.Willow plants (Salix cv. Aquatica gigantea) grown in hydroponic culture media were preincubated for 2 days with or without 0.74 mM NaHCO3. After preincubation, either unlabelled or [14C]‐labelled NaHCO3 was injected into the media and after 1, 5, 10 and 24 h either in light or in darkness the plants were harvested in pieces into liquid nitrogen, lyophilized and burned in a combustion chamber. 14C was transported through the roots to the shoots and leaves both in light and in darkness, although incorporation of 14C in darkness was only half of that in light at the end of the 24‐h feeding period. Both in light and in darkness the amount of 14C increased in all parts of willow plants with time. In light the rate of labelling was highest into cuttings and shoots. In darkness more than half of the total label was detected in cuttings of both the non‐activated and the activated treatments.In the shoots the middle part was most strongly labelled after 5 and 10 h, but after 24 h 14C moved towards the base of the shoot. In the leaves at all feeding times most radioactivity was incorporated into the young, fully open leaves on the upper part of the shoots. Preincubation of plants with unlabelled NaHCO3 in growth media had no clear effect on the rate of DIC uptake either in light or in darkness.
Growth and root hydraulic conductivity of several citrus rootstocks under salt and polyethylene glycol stresses
Authors: Zekri Mongi , Parsons Lawrence R. 
Published: May 2006

The water relations responses to salt of several important citrus rootstocks such as Swingle citrumelo, sour orange, and Milam lemon have not been studied in detail before. Studies were set up to compare growth and root hydraulic properties of these rootstocks to other citrus rootstocks by exposing them to NaCl and polyethylene glycol (PEG) stresses.Seedlings of 7 citrus rootstocks were irrigated for 5 months with nutrient solutions containing NaCl or PEG that had been adjusted to osmotic potentials of ‐0.10, ‐0.20 or ‐0.35 MPa. The 7 rootstocks studied were sour orange (Citrus aurantium), Cleopatra mandarin (Citrus reticulata Blanco), Swingle citrumelo (C. paradisi x P. trifoliata), Carrizo citrange (C. sinensis x P. trifoliata), rough lemon (Citrus jambhiri Lush), Milam lemon (C. jambhiri hybrid), and trifoliate orange (Poncirus trifoliata [L.] Raf.). In both shoot and root growth, Cleopatra mandarin and sour orange were the least sensitive to salt, Milam and trifoliate orange were the most sensitive, and rough lemon, Swingle, and Carrizo were intermediate in sensitivity. Even though the roots were exposed to solutions of equal osmotic potentials, plant growth and root conductivity were reduced more by the PEG treatments than the corresponding NaCl treatments. At ‐0.10 and ‐0.20 MPa, shoot and root dry weights were reduced 16 to 55% by NaCl and 24 to 68% by PEG. Shoot root ratio was lowered at the higher concentrations, particularly by PEG.There was a major decrease in root conductivity caused by NaCl at ‐0.10 MPa (19 to 30% in sour orange and Cleopatra mandarin and 78 to 85% in trifoliate orange and Milam). Conductivity decreased more at ‐0.20 and ‐0.35 MPa, but not proportionally as much as at ‐0.10 MPa. Root weight per unit length increased at the higher salt levels, particularly in trifoliate orange. Water flow rate through root systems followed the same trend as root conductivity; salt affected sour orange and Cleopatra mandarin the least and trifoliate orange and Milam the most. However, reductions in fibrous root length by salt treatment differed. Root lengths of Swingle and Carrizo were least affected by salt while sour orange. Milam, and rough lemon were the most affected. Hence, even though sour orange and Cleopatra mandarin were more tolerant than the other rootstocks in terms of water flow rate or root conductivity, these 2 rootstocks showed a proportionally greater decrease in root length than Carrizo, Swingle, or trifoliate orange.
Dormancy and spring development of lateral buds in mulberry (Morus alba)
Authors: Suzuki Takeo , Kitano Minoru 
Published: May 2006

Patterns of spring development of lateral buds of mulberry (Morus alba L. cv. Shin‐ichinose) coppice shoots on 11‐year‐old low‐pruned stumps varied in response to girdling, pruning and arching. The erect controls showed a weak acrotonic (apex‐favoring) growth habit, in which the majority of the buds, including the basal ones, sprouted and elongated in mid‐ and late April, and hence there was a prolonged imposition of dominance on the upper laterals in mid‐ and late May. In contrast, early spring girdling or pruning enhanced the activity of the upper buds of the proximal (lower) halves of the girdled stems or of the pruned stems, resulting in considerable dominance of the laterals from such buds in late April. Arching markedly inhibited buds on the under side of the arched stems, leading to poor shoots. By late April, the buds on the adaxial (upper) side readily grew into new vertical shoots, which dominated over the lateral ones.When studied by a multiple‐node‐cutting test, increased length of segments of post‐dormant mulberry stems was accompanied by decreased bud activity of the segments and by decreased breaking ability of the lower buds within the segments, suggesting the importance of roots in the weak acrotonic habit of the erect stem in spring. By contrast, the acropetal influences of the attached stems can in part affect dominance relationships, perhaps mediated through competition for factors translocated from the roots. Continuous basal applications of abscisic acid inhibited bud break and shoot growth of the postdormant stem segments, but these inhibitory effects could be reversed by applied gibberellic acid A3 (GA3).Two phases of lateral bud dormancy in erect mulberry coppice shoots were identified. The first was characterized by a smaller breaking capacity in the upper buds than in the lower ones and hence by a basitonic (base‐favoring) gradient in bud growth potential. The second phase corresponded to a restoration of these capabilities in the upper buds and to a change towards a linear gradient in bud growth potential, with disappearance of the dormant condition, in February and March. This gradient change during dormancy release may represent the physiological basis for the weak acrotonic habit of erect mulberry stems in spring.
Quantitative aspects of triacylglycerol metabolism and sterol synthesis from 14C‐acetate in etiolated seedlings of Euphorbia lambii
Authors: Groeneveld Henri W. , Elings Jopie C. , Jorge Blanco Magdalena Soda , Bramwell David 
Published: May 2006

Triacylglycerols occur in both the endosperm and embryo of Euphorbia lambii seeds. Upon germination, the amount of these neutral lipids in the endosperm decreased with 1.06 mg fatty acid day‐1. The embryo contained 1.4 mg fatty acids in the triacylglycerols and this value declined slowly to 0.4 mg seedling‐1 during the 8 day period of endosperm depletion. Radioactive acetate was rapidly taken up by the cotyledons of intact seedlings, translocated throughout the entire seedling, and up to 10.5% of the 14C proceeded to the sterols and latex triterpenols. Maximum uptake values of 1.4 μmol seedling‐1 day‐1 of acetate were measured. Acetate uptake and subsequent incorporation into sterols and triterpenols decreased substantially in the presence of increasing amounts of sucrose (up to 0.3 M). Traces of acetate did not effect [14C]‐sucrose uptake and corresponding synthesis of [14C]‐sterols and triterpenols, but increased concentrations of acetate (0.05 M and up) reduced both uptake of sucrose and its conversion into unsaponifiable lipids.The uptake capacity of the cotyledons for [14C]‐glycerol exceeded the daily production in the endosperm, but only a small amount of label proceeded to the sterols and triterpenols. [14C]‐Triacylglycerols were never detected in the seedling, regardless of the labeled substrate used. Although acetate is an efficient precursor in triterpenol and sterol synthesis, the uptake capacity of the cotyledons for this metabolite is too small in relation to the daily production of water soluble substrates in the endosperm. If acetate is released by the endosperm, only a marginal contribution towards triterpenol and sterol synthesis in the seedling is to be anticipated from this substrate.
NADH‐dependent Fe3+EDTA and oxygen reduction by plasma membrane vesicles from barley roots
Authors: Brüggemann Wolfgang , Moog Petra R. 
Published: May 2006

Brüggemann, W. and Moog, P. R. 1989. NADH‐dependent Fe3+EDTA and oxygen reduction by plasma membrane vesicles from barley roots.Biochemical properties of pyridine‐dinucleotide‐dependent Fe3+‐EDTA reductase were analysed in purified plasma membranes (PM) from barley (Hordeum vulgare L. cv. Marinka) roots. The enzymatic activity preferred NADH over NADPH as electron donor and it was 3‐fold increased in the presence of detergent. The reductase showed a pH optimum of 6.8 and saturable kinetics for NADH with Km (NADH) of 125 μM and Vmax of 143 nmol Fe (mg protein)‐1 min‐1 in the presence of 500 μM Fe3+EDTA. For the dependence of the reaction rate on the iron compound, Km(Fe3+EDTA) of 120 μM and Vmax of 184 nmol (mg protein)‐1 min‐1 were obtained. The activity was insensitive to superoxide dismutase (SOD; EC 1.15.1.1), catalase (EC 1.11.1.6) and antimycin A, but stimulated by an oxygen‐free reaction medium. It could be solubilized by 0.25% (w/v) Triton X‐100. The solubilized enzyme revealed one band in native polyacrylamide gel electrophoresis (PAGE) and in isoelectric focussing (IEF) at pl 7.4 by enzyme staining. Major polypeptides with molecular weights of 94, 106, 120 and 205 kDa corresponded to the enzyme‐stained band from native PAGE.Analysis of oxygen consumption by the membranes revealed the existence of NADH:CK oxidoreductase activity, which was stimulated by salicylhydroxamic acid (SHAM), chinhydron, Fe3+EDTA and Fe3+EDTA but not by K3 [Fe(CN)6] or K4[Fe (CN)6). The stimulating effect of the iron chelates on oxygen consumption was due to Fe2+ and could be suppressed by bathophenanthroline disulfonate (BPDS), SOD and p‐chloromercurophenylsulfonic acid (PCMS). The results are discussed with respect to the nature of the stimulation.
Abscisic acid and temperature modify the levels of calmodulin in embryonic axes of Cicer arietinum
Authors: Hernández‐Nistal Josefina , Rodriguez Dolores , Nicolás Gregorio , Aldasoro Juan José 
Published: May 2006

Changes in calmodulin (CaM) levels in embryonic axes of Cicer arietinum L. cv. Castellana germinated under three different conditions were measured. Abscisic acid (ABA) and a temperature of 30°C, which delay chick‐pea germination, respectively decreased and increased the concentration of CaM compared to the values obtained under normal germinating conditions (H2O‐25°C). The CaM concentration was higher in those zones of the axes undergoing an active cell division.The compartmentalization of CaM in 36‐h‐old embryonic axes grown under these three conditions was also measured. Cytosolic and mitochondrial CaM was higher in axes where a delayed germination occurred as well as in the cell walls of normally grown ones. On the other hand, CaM was higher in nuclear and microsomal fractions extracted from H2‐O‐25°C‐treated axes. From these data we postulate that delayed germination could be an effect of altered CaM distribution in chick‐pea embryonic axes.
Diagnostic parameters for selecting against novel spruce (Picea abies) decline: I. Tree morphology and photosynthesis response to acute SO2 exposures
Authors: Saxe Henrik , Murali N. S. 
Published: May 2006

The dose‐ and time‐response effects of single 4‐h day‐exposures to 0.50, 0.79, 1.28, 1.58, 2.38 or 3.35 μl l−1 (ppm) SO2 followed by single 3‐h night‐exposures of 0.60, 0.87, 1.54, 1.91, 2.91 or 3.98 μl l−1 SO2 on photosynthesis, transpiration and dark respiration were examined for nine East European (Carpatho‐Ukrainian, ‘Rachovo’) half‐sib families and for two populations, one from the FRG (‘Westerhof’) and one from the GDR (‘Schmiedefeld’) of Norway spruce [Picea abies (L.) Karst.], all in their 4th growing season.Even the lowest SO2 concentration reduced photosynthesis and transpiration within 1 h. Photosynthesis of the different spruce types was affected significantly differently, the most sensitive spruce being suppressed 2.5 times more than the most tolerant spruce. ‘Westerhof’ was more resistant to SO2 than the average ‘Rachovo’ half‐sibs. Neither transpiration (stomatal reaction), which was affected alike by all SO2 concentrations, nor SO2 uptake, explained adequately the effects on photosynthesis. Night transpiration, but not dark respiratin, was stimulated by night SO2 preceded by day SO2 exposure.The gradient of different SO2 sensitivities among young trees from the half‐sib families demonstrated a significant negative correlation with the gradient of different sensitivities to novel decline symptoms of their parents growing in a rural seed orchard in Denmark, and with the gradients of four morphology parameters, (height, branching, branch density and the number of Lammas shoots) of the young trees, which in turn demonstrated a positive correlation with decline sensitivity in the seed orchard. The relative photosynthesis sensitivity and the morphology of half‐sibs may serve as diagnostic parameters for laboratory selection of the most resistent trees to novel spruce decline in the field. There was a positive correlation between SO2 induced scorching of Lammas shoots and the inhibition of photosynthesis, but not between the severity of SO2 scorching and symptoms of novel spruce decline. The two visible types of symptoms looked very different.
Diagnostic parameters for selecting against novel spruce (Picea abies) decline: II. Response of photosynthesis and transpiration to acute NOx exposures
Authors: Saxe Henrik , Murali N. S. 
Published: May 2006

The dose‐ and time‐response effects of sequential 3 h+3 h NO→NO2 day time exposures [0–9 μl l−1 (ppm) NO, 0–7.5 μl l−1 NO2] followed by 3 h+3 h NO→NO2 night‐time exposures (0–9.5 μl l−1 NO, 0–9 μl l−1 NO2) on photosynthesis, transpiration and dark respiration were examined for nine Carpatho‐Ukrainian (‘Rachovo’) half‐sib families and for two populations, one from the FRG (‘Westerhof’) and one from the GDR (‘Schmiedefeld’) of Norway spruce [Picea abies (L.) Karst.], all in their 4th growing season. In a second exposure series the exposure sequence was reversed. None of the treatments induced needle scorching.The higher NOx (NO or NO2) concentrations reduced photosynthesis and transpiration within 1 h. The physiology of the different spruce types was affected significantly differently, the most sensitive spruce having its photosynthesis suppressed 6.6 times and its transpiration 5.5 times more than the most tolerant. ‘Westerhof’ was more sensitive to NO2 than the average ‘Rachovo’ half‐sibs.The gradients of different photosynthesis and transpiration sensitivities among the half‐sibs (and ‘Westerhof’) demonstrated a significant, positive, mutual correlation, but significant negative correlations with the gradient of novel decline symptoms among their parents growing in Danish forests. The relative photosynthesis and transpiration sensitivies may thus serve as diagnostic parameters for laboratory selection of the most resistant trees to novel spruce decline.The average NO2 flux density was three times larger than the average NO flux density. Only for NO2 and in light was stomatal NOx uptake larger than the total NOx uptake. Both night transpiration and dark respiration were stimulated by high concentrations of night NOx, preceded by day NOx exposures.
Diagnostic parameters for selecting against novel spruce (Picea abies) decline: IV. Response of photosynthesis and transpiration to SO2+NO2 exposures
Authors: Saxe Henrik 
Published: May 2006

The dose‐ and time‐response effects of 3 days of 6 h day‐time sequential exposures to NO2, SO2 and SO2+NO2 of 0.45–1.81 μl l−1 (ppm) SO2 and 1.50–7.65 μl l−1 NO2 on photosynthesis, transpiration and dark respiration were examined for nine Carpatho‐Ukrainian half‐sib families and a population from the GFR (‘Westerhof’) of Norway spruce [Piecea abies (L.) Karst.], all in their 5th growing season.SO2+NO2 inhibited photosynthesis and transpiration and stimulated dark respiration more than SO2 alone. SO2 and SO2+NO2 at the lowest concentrations inhibited night transpiration, but increased it at the highest concentration, the strongest effects being obtained with combined exposures. Photosynthesis of the different half‐sib families was affected significantly differently by SO2+NO2 exposures. NO2 alone had no effects.Sensitivity to transpiration decline correlated negatively with branch density. Height of trees correlated postitively with decline sensitivity in the seed orchard. The distribution of photosynthesis and transpiration sensitivities over all tested half‐sib families correlated negatively with the distribution of decline sensitivity of their parents in a rural Danish seed orchard. The relative photosynthesis and transpiration sensitivities may thus serve as diagnostic parameters for selecting against novel spruce decline.
Relation between relative growth rate, endogenous gibberellins, and the response to applied gibberellic acid for Plantago major
Authors: Dijkstra Paul , Ter Reegen Harrie , Kuiper Pieter J. C. 
Published: May 2006

Relationships between relative growth rate (RGR), endogenous gibberellin (GA) concentration and the response to application of gibberellic acid (GA3) were studied for two inbred lines of Plantago major L., which differed in RGR. A4, the fast‐growing inbred line, had a higher free GA concentration than the slow‐growing W9, as analyzed by enzyme immunoassay. GA3 application increased total plant weight and RGR3 particularly for the slow‐growing line. Chlorophyll a content and photosynthetic activity per unit leaf area were decreased, while transpiration rate was unaffected by GA3 application. The increase in RGR by GA3 application was associated with an increased leaf weight ratio; specific leaf area and percentage of dry matter in the leaves were only temporarily affected. Root respiration rate per unit dry weight was unaffected.The correlation between low RGR, low GA concentration and high responsiveness to applied GA3 supports the contention that gibberellins are involved in the regulation of RGR. However, the transient influence of GA3 application on some growth components suggests the involvement of other regulatory factors in addition to GA.
Growth and development of Brassica genotypes differing in endogenous gibberellin content. II. Gibberellin content, growth analyses and cell size
Authors: Rood Stewart B. , Zanewich Karen P. , Bray Doug F. 
Published: May 2006

Three rapid cycling Brassica rapa genotypes were grown in greenhouse conditions to investigate the possible relationships between endogenous gibberellin (GA) content and shoot growth. Endogenous GA1 GA3 and GA20 were extracted from stem samples harvested at 3 weekly intervals and analyzed by gas chromatography‐mass spectrometry with selected ion monitoring, using [2H2]‐GA1 and [2H2]‐GA20 as quantitative internal standards. During the first 2 weeks, GA levels of the dwarf, rosette (ros), averaged 36% of levels in normal plants (on a per stem basis). Levels in the tall mutant, elongated internode (ein), were consistently higher, averaging 305% of levels in normal plants.Differences in shoot height across the genotypes resulted from varying internode length which resulted from epidermal cell length and number being increased in ein and decreased in ros relative to the normal genotype. The exogenous application of GA3 to normal plants increased cell length while the application of paclobutrazol (PP333), a triazole plant growth retardant, reduced cell size. Thus, exogenous GA manipulations mimicked the influence of the mutant genes ros and ein. The dwarf, ros, had reduced shoot dry weights and relative growth rates compared to the other genotypes. Total dry weights were similar in ein and the normal genotype but stem weights were increased in ein, compensating for decreased leaf weights. Thus, the gibberellin‐deficiency of ros resulted in generally reduced shoot growth. The overproduction of endogenous GA by ein did not result in enhanced shoot growth but rather a specific enhancement of internode elongation and stem growth at the expense of leaf size.
Salinity effects on CO2 assimilation and diffusive conductance of cowpea leaves
Authors: Plaut Z. , Grieve C. M. , Maas E. V. 
Published: May 2006

The effect of NaCl salinity at concentrations of 43–173 mM in nutrient solution on net gas exchange of attached cowpea [Vigna unguiculata (L.) Walp cv. California Black‐eye No. 5 (CB5)] leaves was investigated under both greenhouse and growth chamber conditions.There was a marked decrease in leaf conductance to water vapor after exposure to low salinity levels and a slighter decrease when salinity levels were higher. The decrease in net assimilation was much more gradual throughout the entire salinity range. The altered responses of net assimilation and leaf conductance to salinity were more evident at a high light intensity. A decrease in intercellular partial CO2 pressure [p(CO2)] was found at the low and intermediate salinity levels but not at the high level. These findings suggest that CO, assimilation was mainly controlled by stomatal conductance and the fixation of CO, might have been increased due to stimulated biochemical activity or to higher chlorophyll concentration per unit leaf area. A decrease in assimilation was already found one day after salinization and pro‐ceeded up to 4 days when it was inhibited by 50% at 43 mM NaCl and up to 85% at 173 mM. The decrease in transpiration was larger than the decrease in net assimila‐tion, and both were attributed to osmotic stress. Partial recovery was found thereaf‐ter and new steady‐state rates, in the range of 55 to 100% of the control, were then obtained for salinity levels between 43 and 130 mM. Inhibition of net CO, assimila‐tion at this stage was attributed partly to a specific sodium effect and partly to plant water status. A linear relationship between leaf sodium content and net photosynthe‐sis was also evident at this stage. Net CO, assimilation recovered more completely than transpiration when salt stress was removed, but at 173 mM NaCl recovery was neglible.