bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sugar and Amino Acid Content of Poa pratensis Infected with Ustilago striiformis and Urocystis agropyri
Authors: HODGES CLINTON F. , ROBINSON PHILIP W. 
Published: April 2006

AbstractLeaf and root tissues of Poa pratensis L. showing distinct morphological changes associated with infection by Ustilago striiformis (West.) Niessl var. poae (stripe smut) or Urocystis agropyri (Pruess) Schroet. (flag smut) were analyzed for total soluble sugars and free amino acids. Decreases in the quantity of soluble sugars in stripe‐smutted plants were not significant, indicating that the presence of U. striiformis sori in leaf tissue does not interfere with photosynthesis of the host. Severe decreases in the quantity of soluble sugars in flag‐smutted plants suggest that U. agropyri either directly impairs photosynthesis or effectively metabolizes the photosynthate. Both pathogens caused significant decreases in total free amino acids in leaf and root tissues. The negligible decrease in soluble sugars in stripe‐smutted plants was associated with a disproportionate decrease in free amino acids, suggesting that the pathogen either metabolizes amino acids or inhibits their synthesis. The severe decrease in amino acids in leaves and roots of U. agropyri‐infected plants is believed due to carbohydrate starvation. It is probable that morphological changes in U. agropyri‐infected plants, including reduced branching, dwarfed leaves and root systems, and the inability to produce inflorescences, are probably the direct result of severely reduced levels of sugars and amino acids. The reduced branching, somewhat smaller root systems, and inhibition of inflorescence production on plants infected by U. striiformis probably are associated to some extent with decreases in amino acids. The upright elongated leaves of U. striiformis‐infected plants, however, cannot be attributed to the decrease in amino acid content and are suggestive of hyperauxiny.
Uptake of Iodide by Excised Bean Roots
Authors: KAUFHOLZ H. , REINIGER P. 
Published: April 2006

AbstractIn view of eventual hazards of I‐129 from nuclear fuel elements, the uptake of iodide by excised 10‐day‐old bean roots (Phaseolus vulgaris L. cv. Berna) was studied using a radiotracer technique. The uptake in the range of 5 × 10−9 to 10−6M iodide can be represented by a single phase obeying Michaelis‐Menten kinetics.
Cell Suspension and Callus Culture from Somatic Tissue of Maize
Authors: OSWALD T. H. , NICHOLSON R. L. , BAUMAN L. F. 
Published: April 2006

AbstractCell suspension and callus cultures from somatic tissue of inbred lines of maize (Zea mays L.) were cultured on media that were defined via modification of a Linsmaier and Skoog preparation. Germlings incubated on the primary medium originally employed required long‐term incubation for callus induction. Modification of the primary medium with high levels of iron and (ethylene dinitrillo)tetraacetic acid (EDTA), B vitamin amendments and vitamin E, shortened incubation by 75% and nearly doubled the percentage of germlings which produced callus. Callus did not remain viable in subcultures to the secondary medium originally employed, whereas a preparation, developed via modification of the original secondary medium, enabled perpetuation of callus through repeated subculture. Modification with high levels of iron and EDTA, plug B vitamins and vitamin E, with decreased concentrations of five inorganic salts, suppressed aberrant organogenesis and stabilized culture growth as viable callus. Similar modification, with the exception that EDTA was omitted, was employed for the development of a liquid medium. Tonicity of the medium was adjusted with a lowered level of sucrose, with the liquid further modified by addition of acetate. Upon development of this liquid, maize became the sixth monocot species for which somatic cells remain viable through repeated subculture in liquid suspensions.
Thigmonastic Coiling of Tendrils of Passiflora quadrangularis is Not Caused by Lateral Redistribution of Auxin
Authors: JUNKER STEFFEN 
Published: April 2006

AbstractThe effect of thigmotropic stimuli on the distribution of exogenously applied indoleacetic acid in intact tendrils of Passiflora quadrangularis L. has been investigated. Tips of tendrils were dipped in solutions of IAA‐2‐14C for 12 h and subsequently stimulated by exposure to carbon dioxide or mechanically by rubbing. The content of 14C in dorsal and ventral halves was analysed before, during and after coiling. Our experiments failed to detect any difference from the initial dorsal: ventral ratio of 14C (44:56) as a possible consequence of stimulus or of coiling. This suggests that thigmotropic curvature is not dependent on lateral movement of auxin, supporting a theory of a built‐in asymmetrical reaction of the tissues to equal amounts of auxin and CO2, respectively.
Chlorate Toxicity and Nitrate Reductase Activity in Tomato Plants
Authors: HOFSTRA J. J. 
Published: April 2006

Chlorate damage was studied in tomato plants (Lycopersicum esculentum cv. Moneymaker) that were supplied with a nitrogen‐free nutrient solution or with a nutrient solution, containing either nitrate or ammonium as a nitrogen source. Damage was low in ammonium‐fed plants and high in nitrate‐fed plants and in nitrogen‐less plants. Nitrate reductase activity could be detected in all treatments, although the activity was highest in the nitrate‐fed plants.The hypothesis that chlorate can be used as a substrate by the enzyme nitrate reductase in higher plants, was studied and proved to be true for the tomato plants, as was found earlier for Escherichia and Chlorella. The affinity of the enzyme for chlorate was lower than for nitrate, the Km being 4 mM and 0.15 mM respectively. Induction of the enzyme by chlorate could not be detected. The enzyme activity was lowered in leaf discs after a 7 h treatment with chlorate and the inhibition was proportional to the chlorate concentration of the medium.The results were discussed in terms of competition between nitrate and chlorate at the uptake and the enzyme site and with regard to a possible influence of chlorate on synthesis and breakdown of the enzyme.
Effect of NaCl on the in vitro Activity of Malate Dehydrogenase in Salt Marsh Halophytes of the U.S.
Authors: CAVALIERI ANTHONY J. , HUANG ANTHONY H. C. 
Published: April 2006

AbstractThe in vitro effect of NaCl on NAD‐malate dehydrogenase (E.C. 1.1.1.37; MDH) from desalted extracts of roots and leaves of six salt marsh halophytes was investigated. The plants, all native and important constituents of the salt marshes of the east coast of the U.S., included Spartina alterniflora Loisel., Spartina patens (Aiton) Muhl., Distichlis spicata (L.) Greene, Juncus roemerianus Schleele, Salicornia virginica L., and Borrichia frutescens (L.) DC. In the leaf extracts of all species except Borrichia frutescens, the MDH activity was slightly stimulated by NaCl at concentrations around 0.05 M at optimal pH (8.0–8.5) and was reduced by NaCl in higher concentrations. MDH activity in the leaf extract of Borrichia frutescens was more salt‐tolerant and maximal activity occurred around 0.25 M NaCl at optimal pH (7.0). Even though similar pH optimums for activity were exhibited in the root and leaf extracts of each species, the MDH activity in the root extract was more salt‐tolerant than that in the leaf extract. NaCl at concentrations up to 0.1 M stimulated the MDH activity in the root extracts of all species except that of Borrichia frutescens, which had an optimal activity in 0.5 M NaCl. In the root and leaf extracts of Borrichia frutescens, the activity of cytosol MDH was much more salt‐tolerant than that of the mitochondrial MDH. A shift of the optimal pH to more acidic values with increasing concentrations of NaCl was noted in the extracts of all the species except Borrichia frutescens. The action of NaCl on MDH activity appeared to be a general ionic effect as judged by the response of the enzyme activity in the presence of iso‐ionic concentrations of other salts and isoosmotic mannitol. Thus, the response of the MDH from five of the salt marsh plants to NaCl is similar to that of glycophytes. However, Borrichia frutescens possesses a salt‐tolerant MDH that has optimal activity in a salt concentration as high as that of the environment.
A Revised Medium for Growth of Pea Mesophyll Protoplasts
Authors: VON ARNOLD SARA , ERIKSSON TAGE 
Published: April 2006

AbstractThe nutrient requirements of mesophyll protoplasts from Pisum sativum L. cv. Timo have been investigated and a synthetic and completely defined medium has been designed. A high calcium concentration (12 mM) stimulated both protoplast survival and cell division. The content of iron and zinc was also critical. Additions of nicotinic acid, pyridoxine and thiamine were necessary. The protoplast growth was enhanced when some amino acids were included in the medium. An absolute requirement for auxin and cytokinin was shown.In the revised medium about 90% of the isolated protoplasts survived and formed a cell wall. The first divisions were observed after 5 days and after 1 week 10–20% of the cells had divided at least once.
Adaption to Photosynthesis and Diurnal Oscillation of Root Respiration Rates for Lolium multiflorum
Authors: HANSEN G. K. 
Published: April 2006

AbstractContinuous measurements of CO2‐release from intact roots of Lolium multiflorum growing in nutrient solution were carried out during 3–7 weeks. Periods of days with high level of irradiance and periods with low level alternated. Root respiration rate was found to depend on photosynthesis. The change in root respiration, induced by change in photosynthesis, was delayed. The root respiration rate showed diurnal fluctuations with two characteristic peaks occurring 4–6 and 14–16 hours after onset of the photoperiod. The amplitudes increased with increasing photosynthesis. The frequencies were independent of the length of photoperiod, when this varied between 8 and 16 hours. The fluctuations are discussed in relation to diurnal fluctuations in protein synthesis.
The Effect of Different Portions of the Sunlight Spectrum on Ethylene Evolution in Peach (Prunus persica) Apices
Authors: EREZ AMNON 
Published: April 2006

AbstractExposure of peach plants to the blue plus far‐red (B/FR) portions of the sunlight spectrum caused a rapid rise in ethylene evolution from their apices. Two days were enough to produce a significant rise in ethylene evolution relative to blue without far‐red or to neutral shade. Maximal level of ethylene evolution in the B/FR light, more than eight times that of the blue or the neutral shade, was reached after four days of exposure. A higher endogenous ethylene content was also found under B/FR relative to blue or to neutral shade conditions. The level of ethylene evolution from peach apices was correlated with their arrested growth as observed a few days later.Exposure of peach plants to dense leaf shade, under the canopy of a big avocado tree, enhanced ethylene evolution from their apices, relative to unfiltered sunlight and to neutral shade. It was suggested that the rise in ethylene evolution in both B/FR and leaf shade conditions resulted from a high far‐red: red ratio. Ethylene was further suggested to act as a mediator of photomorphogenetic regulation of vegetative development in far‐red‐rich tree shade.
Absorption des acides amines par les lutoïdes du latex d'Hevea brasiliensis
Authors: HANOWER P. , BRZOZOWSKA J. , NGORAN M. NIAMIEN 
Published: April 2006

AbstractAbsorption of Amino Acids by Lutoids from the Latex of Hevea brasiliensis.The latex of Hevea brasiliensis is a fluid protoplasm containing organelles with a single membrane that are called lutoids. They are microvacuoles of a lysosomal character. The intact lutoids can easily be isolated in an isotonic medium by the usual procedures of cellular fractionation.Previous studies have shown the existence of a compartmentation of the free amino acids in latex. While acidic components dominate in the cytoplasmic serum, the lutoid serum contains mainly basic components. These findings, as well as the part played by the lutoids in the latex flow and in the process of latex coagulation, led the authors to study the penetration of acidic, neutral and basic amino acids into the lutoids. Labelled amino acids were used for the purpose. Special interest was given to the uptake of lysine, which is transported into the lutoids against a concentration gradient in the absence of a metabolic energy source. The process is linear for at least 30 min and follows Michaelis–Menten kinetics as a function of the lysine concentration. The uptake is strictly temperature and pH dependent. It increases in the presence of ATP. Lysine uptake by lutoids is also increased by application of Ethrel, ethylene generator, to the bark of tapped trees. 2,4‐Dinitrophenol (2,4‐DNP), ammonium chloride and N‐ethylmaleimide (NEM) inhibit the influx. Neutral l‐amino acids do not affect the uptake of l‐lysine, while l arginine inhibits lysine transport competitively. d‐lysine is without effect on l‐lysine uptake by lutoids. Under conditions used in this study no lysine efflux is observed. A mechanism governing the penetration of basic amino acids against a concentration gradient is discussed, and the possible role of a proton gradient is suggested.
Influence of Light and Temperature on Photosynthesis and Transpiration in Some C3 and C4 Vegetable Plants from Kenya
Authors: IMBAMBA S. K. , TIESZEN LARRY L. 
Published: April 2006

AbstractPotted vegetable plants of Amaranthus lividus, Gynandropsis gynandra and Crotalaria brevidens were grown outside under normal tropical conditions and rate of photosynthesis and transpiration were determined simultaneously in attached leaves under a range of leaf temperatures and irradiances. Photosynthetic rates were consistently higher in G. gynandra than in A. lividus and C. brevidens. However, in C. brevidens and G. gynandra the leaf resistances were lower and transpiration rates were higher than those in A. lividus.The results on optimum temperature requirements for maximum rates of CO2 fixation, coupled with data on CO2 compensation points and leaf anatomy provided clear evidence that G. gynandra and A. lividus are C4 species, while C. brevidens is a C3 species. The differential effects of light intensity and temperature on stomata and mesophyll resistances in C3 and C4 species are discussed in relation to rates of photosynthesis and transpiration.
Čerenkov Counting of 24Na in Suspension Cultures — an Economical Use of Scintillation Apparatus for Studying Ion Exchange
Authors: PENNARUN A. M. , KOVOOR A. , HELLER R. 
Published: April 2006

AbstractThe feasibility of using Čerenkov radiation to estimate 24Na in the study of ion exchange in cell suspension cultures of Acerpseudoplatanus has been investigated. Some practical procedures for preparing samples and counting have been proposed according to the particular need of the experiment and the desired degree of counting efficiency.
Morphactin and Adventitious Root Formation in Pea Cuttings
Authors: KHAN A. RAUF , ANDERSEN A. SKYTT , HANSEN JÜRGEN 
Published: April 2006

AbstractStock plants of pea (Pisum sativum L. cv. Alaska) were grown at different controlled levels of irradiance (4, 16 or 38 W m−2) for 11 days from sowing. Morphactin (CFM, methyl‐2‐chloro‐9‐hydroxy‐fluorene‐9‐carboxylate) was applied to the apex of the stock plants 3 days before cuttings were excised. The cuttings were rooted at 16 W m−2. High levels of morphactin (>5 × 10−3 mg l−1) inhibited root formation in the cuttings. Low concentrations of CFM (5 × 10−5 mg l−1) promoted the formation of adventitious roots in cuttings from plants grown at all three levels of irradiance, with the most pronounced effect in cuttings from 4 W m−2. Measurements of ethylene evolution by CFM‐treated plants 3 days after application, revealed a stimulatory effect on ethylene production by high CFM concentrations.
Occurrence and Heterogeneity of Chymotrypsin Inhibitors in Vegetative Tissues of Barley
Authors: KIRSI MARKKU , MIKOLA JUHANI 
Published: April 2006

AbstractInhibitors of chymotrypsin and the alkaline proteinase of Aspergillus oryzae were present in the shoots of barley seedlings and weak activities were also detected in the shoot tops of 6‐week‐old plants. Treatments which induce inhibitor formation in tomato and potato leaves had no effect when tested on mature leaves, seedlings, or young tillers of barley.Fractionation experiments with isoelectric focusing showed that the barley leaves contained several proteinase inhibitors acting on both chymotrypsin and the Aspergillus proteinase, and one inhibitor which acted only on the Aspergillus enzyme. All of these inhibitors were different from the five Aspergillus proteinase inhibitors which are abundant in the endosperm of resting seeds. Two chymotrypsin inhibitors with weaker activity on the Aspergillus proteinase were present in rootlets and also in embryos of resting seeds. These inhibitors were different from both the endospermal inhibitors and the inhibitors present in young leaves.
Effect of Succinic Acid‐2,2‐Dimethylhydrazide on Endogenous Auxin Level in Apple Shoots
Authors: JINDAL K. K. , DALBRO SVEN 
Published: April 2006

AbstractEndogenous auxin levels in the shoots of apple cv. Ingrid Marie (red mutant) treated with SADH (succinic acid‐2,2‐dimethylhydrazide) were measured. SADH was applied in aqueous solution at 12.5, 25 or 50 mM concentrations in June, 3 weeks after flowering. The defoliated shoot tips were analysed just before SADH spray and 7, 15, 30 and 60 days after spraying. Similar treatments had been made in earlier years.When analysed before the treatment of the year started, shoot extracts of control plants contained higher auxin level than those shoots which were to receive SADH treatment, indicating a residual effect of SADH treatmens during previous years. There was almost no auxin activity in the shoots analysed after 7, 15 and 30 days of SADH treatment. The control plants maintained a high level of auxin activity during this period. However, after 60 days of treatment, shoots treated with 25 or 50 mM exhibited higher auxin activity than control shoots. There appears to be no relationship between the SADH concentration and reduction in auxin activity in the shoots at early stages after treatment.
A Replica Plating Method for Plant Cells
Authors: SCHULTE U. , ZENK M. H. 
Published: April 2006

AbstractA replica plating method is described for plant cells growing in Petri dishes. The method involved a uniform application of plant cells (Morinda citrifolia L.) by spraying cells evenly on agar plates containing 60% conditioned medium. Subsequently the cells were allowed to grow through a nylon net. The net was removed from the master plate and placed upside down on replica plates. Cells from colonies adhering to the threads of the net were thus transferred to the replica plate and yielded colonies that, after a growth period of about 10–20 days, corresponded in position to the colonies on the master plate. An 80% transfer of colonies from the master plate to the copy plate was possible.
Cysteine and Methionine Regulation of Sulfate Uptake in Potato Tuber Discs (Solanum tuberosum)
Authors: MAGGIONI ANGELO , RENOSTO FRANCO 
Published: April 2006

AbstractSulfate uptake in potato tuber discs is inhibited by cysteine and methionine with an 8 h lag period. Cysteine, but not methionine, inhibition can be reversed by washing the treated discs. During the experimental period cysteine is rapidly metabolized, while methionine persists as a free amino acid. Amino acid inhibition of sulfate uptake is overcome by increasing sulfate concentration. The kinetic parameters change suggesting a loss of flexibility of the sulfate uptake system caused by sulfur amino acids.
Kinetics of Manganese Uptake by Intact Citrus Seedlings
Authors: HASSAN M. M. 
Published: April 2006

AbstractUptake of manganese by intact citrus seedlings can be represented by three phases of a single, multiphasic isotherm in the range 10−8M–2× 10−4M. The phases are separated by marked jumps and the kinetic constants increase upon transition to higher phases.
Isolation of Mitochondria from Orobanche, a “Total” Root Angiospermic Parasite
Authors: SINGH PRIKHSHAYAT , KRISHNAN P. S. 
Published: April 2006

AbstractMitochondria were isolated from the scapes of Orobanche cernua. On the basis of comparative studies with four media, a mannitol grinding medium was selected at a slightly alkaline pH and supplemented with EDTA, metabisulphite, BSA and soluble PVP. Various intermediates of the Krebs cycle, pyruvate, glutamate and NADH were oxidized by the isolated particles, though with different efficiencies. The rate of oxidation was steady for every intermediate tested over a 60 min period, except for NADH. In the majority of cases, the oxidation was accompanied by efficient coupling with phosphorylation. Antimycin A led to significant reduction in the oxygen uptake in the presence of succinate and complete suppression of phosphate‐esterification. The amount of protein recovered in the mitochondrial fraction was comparable with the reported recoveries from a number of plant tissues. The biochemical integrity of mitochondria in the particulate fraction appeared possible from: (a) the absence of respiratory response to added cytochrome c during the oxidation of succinate, (b) insignificant oxidation of exogenously added pyruvate in the absence of sparker and (c) the ability to satisfactorily couple phosphorylation to the oxidation of a number of substrates.
The Effect of Ageing on the Leghemoglobin of Cowpea Nodules
Authors: SWARAJ K. , GARG O. P. 
Published: April 2006

AbstractExperiments were conducted to study the effect of ageing of the host and senescence of the nodules on the content and composition of the proteins of leghemoglobin in nodules of cowpea (Vigna sinensis L.). Total and heme protein contents of leghemoglobin were the highest in the red nodules and dwindled with the onset of nodule senescence. In the fully senescent green nodules the total proteins decreased to a very low level, while the heme proteins were almost absent. Disc electrophoretograms of leghemoglobin obtained from red and brown nodules showed nine bands out of which only four gave positive test for heme. Greening of the nodules resulted in a considerable reduction in the intensity of the bands. Senescence of the host plant resulted in a reduction in the number of leghemo‐globin proteins in all types of nodules and brought about a drastic change in their electrophoretic mobility.
Induced Embryo Formation in Anther Cultures of Several Anemone Species
Authors: JOHANSSON LARS , ERIKSSON TAGE 
Published: April 2006

AbstractEmbryo formation was induced in anther cultures of Anemone virginiana and some other species of the same genus. Activated charcoal was included in the culture medium which gave the higher percentage embryos. When the cytokinin 2ip was included (10−6M) embryo formation was also induced but at a lower percentage. This indicates that abscisic acid (ABA) can be involved in the normal inhibition of embryo formation in pollen.