bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Daylength on Endogenous Gibberellins in Solanum andigena III. Gibberellin Production by the Leaves
Authors: RAILTON I. D. , WAREING P. F. 
Published: April 2006

AbstractUsing an agar diffusion technique, it was found that leaves from potato plants growing under long days produced more gibberellin‐like substances than did leaves from plants growing under short days. Short day plants irradiated with red light during the long dark period and harvested during the ensuing light period, contained levels of gibberellin‐like substances approximating those found in long day grown plants.Red irradiation during the long dark period also resulted in an increase in gibberellin production in short day plants. Four zones of gibberellin‐like activity (A, B, C, D) were separated by thin layer chromatography in extracts from potato leaves. Red light treatment reduced the levels of peak D and brought about a concomitant increase in the levels of peak A.
Further Investigations on the Nature of the Heat Resistance of Thermophilic Bacteria
Authors: LJUNGER CLAES 
Published: April 2006

AbstractWhen cells of Bacillus stearothermophilus, strain NCA 1503, were grown in tryptone starch broth and subsequently transferred to tris buffer, a fraction of the cells: rapidly died in ttie buffer. This fraction increased with increasing content of calcium chloride in the growth medium. The' addition of sodium, potassium or magnesium chloride to the growth medium had no such effect. The rapid dying of the cells in tris buffer was associated with a leakage of organic material and calcium ions from the cells. The results obtained are probably caused by a damage to the osmotic barrier of the cells during their contact with the buffer. Observations: made during the present investigation and a previous one (Ljunger 1970) indicate that the heat resistance of thermophilic bacteria depends on the maintenance of a high intracellular concentration of free calcium ions.
A Technique for Studying the Adsorption, Absorption and Metabolism of Amino Acids in Intact Apple Stem Tissue
Authors: HILL‐COTTINGHAM D. G. , LLOYD‐JONES C. P. 
Published: April 2006

AbstractSolutions of amino acids are introduced rapidly into the xylem of short lengths of stem. At sampling the intact stem is first perfused with a salt solution to remove the amino acids still reversibly adsorbed by cation exchange. This fraction of the applied amino acids is thus distinguished from that absorbed into the tissues which is subsequently extracted from the disintegrated stem by aqueous ethanol.The potential value of this technique is discussed and illustrated with some results using carbon‐14 labelled amino acids in apple stems.
Short‐ and Long‐term Effects of High Temperatures (47–49°C) on Tobacco Leaves. II. O2 Uptake and Amylolytic Activity
Authors: ITAI C. , BENZIONI ALIZA 
Published: April 2006

AbstractDetached tobacco (Nicotiana rustiest L.) leaves were exposed for 2 min to a temperature range of 24° to 47.5°C. The heat treatment enbanced O2 uptake by 30 Vs. Likewise, amylolytic activity in chloroplast extracts was intensified; this activity being observed also in situ. The enhancements can be reversed either by short‐term cold treatment (7°C for 10 min), or by application of kinetin.
Action Spectrum of Photosynthesis for Skeletonema costatum Obtained with Carbon‐14
Authors: IVERSON RICHARD L. , CURL HERBERT 
Published: April 2006

AbstractThe quantized action spectrum of photosynthesis for Skeletonema costatum was obtained from values of photosynthetic 14CO2 uptake at various wavelengths of light isolated “with a diffraction grating monochromator. The quantized action spectrum of photosynthesis exhibited maxima at wavelengths similar to maxima in the absorption spectrum, in vivo, of a suspension of S. costatum cells. While the 14CO2 technique will provide an accurate action spectrum of photosynthesis for diatoms, a large number of samples is required in order to minimize sampling error.
Variations in Uptake of Sodium and Rubidium Along Barley Roots
Authors: ESHEL A. , WAISEL Y. 
Published: April 2006

AbstractVariations in uptake of sodium and rubidium were ob) served along the apical 8 cm segments of barley roots. Dif) ferent patterns of uptake were obtained for low‐ and for high‐salt roots. The validity of using batches of entire barley roots for kinetic analysis of ion uptake is questioned.
Leaf Water Potential Response to Transpiration by Citrus
Authors: CAMACHO‐B SAUL E. , KAUFMANN MERRILL R. , HALL ANTHONY E. 
Published: April 2006

AbstractThis paper reports on further studies of a model for interpreting leaf water potential data for Citrus. Experimental data confirmed the assumption that the ratio of vapor pressure deficit to leaf diffusion resistance adequately estimates transpiration when leaf‐to‐air temperature differences are small. Data collected diurnally indicated that the relationship between leaf water potential and transpiration followed a sequence of steady states without hysteresis. No difference in water transport characteristics was found for Valencia orange on three rootstocks in well‐watered soil, but the two rootstocks Cleopatra mandarin and Rangpur gave slightly greater leaf water stress in Valencia orange leaves than‘Troyer’ citrange rootstock at high transpiration rates under mild soil water deficits. In laboratory studies, previously unstressed seedlings had higher leaf water potentials than field trees at equivalent transpiration rates. After several drying cycles, however, leaf water potentials were similar to those observed in the field.
Distribution of Physiological Activities in the Cotyledons of Germinating Seeds
Authors: MOROHASHI Y. , SHIMOKORIYAMA M. 
Published: April 2006

AbstractFrom autoradiographical experiments on water‐imbibing pea (Pisum sativum) or Phaseolus mungo cotyledons supplied with glucose‐14C or iodoacetic acid‐14C, it was shown that the compounds did not penetrate into the innermost part of the cotyledons but remained in the peripheral region during the early germination period. Changes in the rates of incorporation of 14C into alcohol from glucose‐14C were examined during the early period of germination, and it was concluded that glucose supplied exo‐genously was actively metabolized in the peripheral region. Endogenous alcohol formation was supposed to occur mainly in the peripheral region in the early phases of germination. On the basis of these results, the heterogeneity of the distribution of physiological activities in the cotyledon is discussed.
Characterization and Properties of a Protochlorophyllide Ester in Leaves of Dark Grown Barley with Geranylgeraniol as Esterifying Alcohol
Authors: LILJENBERG CONNY 
Published: April 2006

AbstractThe protochlorophyllide ester isolated from dark grown barley leaves was shown to contain geranylgeraniol as esterifying alcohol. No phytylester was found. The qualitative analyses were performed with combined gas chromatography‐mass spec‐trometry. Chromatographic separation and spectrofluorometric determination of the protochlorophyll and chlorophyll pigments before and after irradiation of the dark grown leaves with light flashes at 2°C showed that part of the protochlorophyllide ester was photoconverted to chlorophyll a.
The Effect of Age, Pre‐conditioning, and Water Stress on the Transpiration Rates of Douglas‐Fir (Pseudotsuga menziesii) Seedlings of Several Ecotypes
Authors: UNTERSCHEUTZ P. , RUETZ W. F. , GEPPERT R. R. , FERRELL W. K. 
Published: April 2006

AbstractSeedlings of Douglas‐fir from seed of a number of mesic and xeric origins were grown in growth chambers and a nursery to various ages up to 16 weeks. Measurements were made to determine the effect of seedling age, growth chamber and nursery pre‐conditioning, and seed source on transpiration rates under closely controlled laboratory conditions. Additional experiments were conducted on seedlings of two contrasting ecotypes to determine the effect of different pre‐conditioning combinations of plant and soil water potential on seedling transpiration rates. Results show that well‐watered seedlings of two mesic ecotypes show no decline in transpiration rates per unit leaf area up to 16 weeks of age while corresponding seedlings of three exeric ecotypes do decline. The growth chamber pre‐conditioning results in lower seedling transpiration rates and more decline in seedling transpiration rates with increasing plant water stress than for nursery pre‐conditioning. In a similar way, the xeric ecotype seedlings have more decline in transpiration rates with increasing plant water stress than do the mesic ecotype seedlings. Soil water potential influences transpiration rates through pre‐conditioning effects. Seedlings which have experienced prior soil moisture stress decrease transpiration more in response to low plant water potentials than do plants which have experienced no soil moisture stress. These behavioral characteristics illustrate adaptive means by which seedlings conserve water through the interaction of genetic and preconditioning mechanisms.
Stacking Capacity and Chlorophyll Forms of Thylakoids in Normal and Mutant Maize Chloroplasts of Different Granum Content
Authors: DEMETER S. , HORVÁTH G. , JOÓ F. , HALÁSZ N. , FALUDI‐DÁNIEL ÁGNES 
Published: April 2006

AbstractStacking of chloroplast lamellae, isolated from normal and carotenoid mutant chloroplasts of maize (Zea mays L.), was determined after a high‐salt treatment.Stacking of isolated lamellae under favourable ionic conditions was almost identical with that occurring in intact chloroplasts; thus, differences in granum content could be attributed to the architectural properties of lamellae.Gaussian analyses, performed on the red band of room temperature absorption spectra, have shown that chloroplasts with lamellae of high stacking capacity contain relatively more Chl a662 than chloroplasts containing lamellae of low stacking capacity. The presence of Chl a705–708 was characteristic of preparations containing considerable amounts of stroma lamellae.
Action Spectrum for Photoactivation of the Water‐splitting System in Plastids of Intermittently Illuminated Wheat Leaves
Authors: INOUE YORINAO , KOBAYASHI YOSHICHIKA , SAKAMOTO EMIKO , SHIBATA KAZUO 
Published: April 2006

AbstractThe chloroplasts from wheat leaves developed under intermittent illumination (1 ms light + 12 min dark) were able to photoreduce DPIP with DPC as electron donor but unable to photoreduce DPIP with water as electron donor. On exposure of these leaves to continuous light, the Hill activity with water as electron donor was rapidly induced. The photoactivation was sensitive to the treatment with DCMU prior to exposure to continuous light. The action spectrum for the photoactivation showed a sharp band at 680 nm with a distinct shoulder at 650 nm, and was similar to the absorption spectrum of photosytem‐2 particles. These data suggest that the electron transfer driven by photosystem 2 is essential for the activation of the water‐splitting system in the chloroplasts of intermittently illuminated leaves.
Uptake of l‐Phenylalanine in Synchronous Chlorella fusca. Characterization of the Uptake System
Authors: PEDERSEN ÅSE GRAN , KNUTSEN GJERT 
Published: April 2006

AbstractPhenylalanine uptake in Chlorella fusca was measured, using the membrane filter technique. The cells were synchronized, and harvested at specific points of the life cycle. Experiments with autospores showed that the uptake followed saturation kinetics, with a Km= 5 μM. Vmax, was 0.1 nmol/min × 107 cells. The optimum temperature for the uptake was 40°C, and the activation energy was 1700 J/mol. The uptake showed a high specificity towards l‐phenylalanine; presence of the unlabelled stereoisomer did not inhibit the uptake. Uptake of l‐phenylalanine was inhibited in the presence of other analogues or other amino acids, but only if they were present in concentrations considerably higher than that of L‐phenylalanine. Variations in the ratio of Na4+ to K+ in the external solution during uptake experiments did not have any influence upon the uptake rate of l‐phenylalanine. The cells were able to take up the amino acid against a concentration gradient. At pool maximum the ratio between internal and external amino acid concentration was 1000/1. 2,4‐Dinitro‐phenol inhibited the uptake completely. Exchange between internal and external l‐phenylalanine could not be demonstrated. The Km value did not change during the life cycle of the cells. The uptake rate reached a maximum at the end of the light period, and fell to a minimum just before sporulation started. It is concluded that Chlorella fusca cells have a highly specific, active uptake system for l‐phenylalanine. The system is constitutive, independent on the K or Na concentration, and the mechanism of uptake does not change during the life cycle of the cells.
Effect of Ethylene on the Phenylalanine Ammonia‐lyase Activity of Carrot Tissues
Authors: SARKAR SUBODH K. , PHAN C. TON 
Published: April 2006

AbstractEthylene stimulated the activity of l‐phenylalanine ammonia‐lyase (PAL) in carrot (Daucus carota L.) tissues. It is also known to induce the formation of isochlorogenic acid. However, the induction patterns were different for isochlorogenic acid and PAL activity. Ethylene action seems to be indirect, as it did not affect the PAL activity of cell‐free extracts.
Effect of Cd on Photosynthesis and Transpiration of Excised Leaves of Corn and Sunflower
Authors: BAZZAZ F. A. , ROLFE G. L. , CARLSON ROGER W. 
Published: April 2006

AbstractDetached corn and sunflower leaves exposed to various concentrations of Cd, supplied as CdCl2, exhibit reduced photosynthesis and transpiration. The reduction is dependent on the concentration of CdCl2 solution and generally becomes more pronounced with time. In sunflower, net photosynthesis and transpiration are completely inhibited within 45 min after the introduction of 18 mM Cd. Within two hours net photosynthesis is reduced to 40% and 70% of maximum after the introduction of 9 and 4.5 mM Cd respectively. In corn the trend of photo‐synthetic response to Cd is similar to that in sunflower except that the inhibition in corn is more pronounced at all treatment levels. A strong linear relationship between photosynthesis and transpiration inhibition is obtained in both species suggesting that Cd contamination induces stomatal closure.
Action Spectrum for the Timing of Photo‐Induced Cell Division in Adiantum Gametophytes
Authors: WADA MASAMITSU , FURUYA MASAKI 
Published: April 2006

AbstractThe photo‐induced cell division in single‐celled protonemata of the fern Adiantum capillus‐veneris was studied. When the protonemata were exposed to monochromatic light at 50 nm intervals between 350 and 750 nm, irradiations in the blue and near‐ultraviolet regions effectively induced cell division, while wavelengths longer than 550 nm showed no such effect. As reciprocity between duration and intensity was observed within the range of incident energy used, the action spectrum for the frequency of the photo‐induced cell divisions 24 h after irradiation was determined between 360 and 510 nm at 10 nm intervals. Furthermore, the previously known effect of phytochrome on the timing of the cell division was minimized by a short exposure to red light given immediately after the monochromatic irradiation. The resulting action spectra showed a peak in the neighborhood of 460 nm with shoulders and another peak in the near‐ultraviolet region.
Macromolecular Physiology of Plastids
Authors: NIELSEN OLE FREDERIK , GOUGH SIMON 
Published: April 2006

AbstractThe composition and amount of carotenoid pigments were determined in etiolated seedling leaves of 6 barley (Hordeum vulgare L.) mutants, comprising 1 xantha and 5 tigrina mutants. All mutants had on a mole basis approximately the same content of carotenoids as the wild type.The mutants xan‐u21, tig‐n32, and tig‐33 contained significantly higher amounts of carotenes than the wild type, ranging from 32 to 68% of the total carotenoid content as compared to the 4–8% found in the wild type. In the mutants tig‐b23 and tig‐o34, only a slight increase in the amount of carotenes was notable. The carotene content and composition in tig‐d12 was indistinguishable from that of the wild type.The carotenes extracted from xan‐u21, tig‐b23, tig‐n32, tig‐33, and tig‐o34 were characterized by adsorption chromatography and spectrophotometry. Mutant xan‐u21 is in the dark blocked in β‐carotene synthesis, and accumulates the aliphatic polyenes: phytofluene, proneurosporene, poly‐cis‐lycopenes, neo‐lycopene and lycopene. The other four mutants synthesize β‐carotene, but accumulate in addition various higher saturated carotenes, the main components being ζ‐carotene in tig‐b23, a lycopenic pigment in tig‐n32 and tig‐33, and lycopene in tig‐o34.Accumulation of higher saturated carotenes appears correlated with specific aberrations of the membrane structure in plastids. The regulation of carotene and protochlorophyllide syntheses in etioplasts are closely linked as shown by the single gene mutants which affect both pathways. However, several mutants have been identified which cause defects in protochlorophyllide synthesis only.
Effects of Hydroxyproline and other Amino Acid Analogues on the Growth of Pea Root Segments
Authors: VAUGHAN D. , DEKOCK P. C. , CUSENS EVELYN 
Published: April 2006

AbstractChanges in the lengths and growth rates of isolated 2–4 mm pea root segments, cultured in sucrose media under aseptic conditions, were paralleled by changes in invertase development and in chloride and leucine uptakes. The amino acid analogues o‐, m‐ and p‐fluorophenylalanine, azetidine‐2‐carboxylic acid and ethionine inhibited growth with corresponding changes in invertase activity and in chloride and leucine uptakes. In contrast hydroxyproline, which under the conditions used may be regarded as an analogue of proline, enhanced both the growth rate and duration of growth but had little effect on the several parameters of protein synthesis which were measured. No amino acid tested affected changes in growth, invertase activity or the uptake of chloride and leucine, but they prevented the effects of the corresponding analogues. The results show that although extension growth is dependent on continuous protein synthesis, only specific proteins, probably in the cell wall, play a key role in this process.
Die Hemmung der lichtinduzierten Chlorophyll‐, Carotinoid‐ und Anthocyansynthese durch Äthanol
Authors: LICHTENTHALER HARTMUT K. , THIESS DOROTHEA E. 
Published: April 2006

Abstract The Inhibition of the Light Induced Chlorophyll, Carotenoid and Anthocyan Synthesis by Ethanol.It is shown that already low concentrations of ethanol inhibit the light induced formation of pigments (chlorophylls, carotenoids, anthocyanins) in Raphanus‐seedlings.The degree of inhibition depends on the ethanol concentration and rises with increasing incubation period. The inhibition of pigment synthesis is reversible, and immediately ceases when ethanol is removed. The formation of chlorophylls and anthocyanin is more repressed than that of carotenoids, and the formation of β‐carotene to a higher extent than that of xanthophylls. It is concluded that ethanol inhibits pigment formation by inhibition of protein synthesis. These results indicate that ethanol and other lower alcohols cannot be used for the solubilizing of organic compounds when these are applied to plant tissues.
Amino Acid Incorporation into Proteins by Plant Mitochondria in the Presence of Some Plant Growth Promoters, Metabolic Inhibitors and Synthetic Messengers
Authors: DE DILIP K. , ROY S. C. 
Published: April 2006

AbstractThe incorporation of 14C‐labelled phenylalanine into proteins of mitochondria prepared from 48‐h germinating seeds of Vigna sinensis (L.) Savi can be stimulated by gibberellic acid (GA3), kinetin and polyuridylic acid [poly(U)]. The incorporation is sensitive to various metabolic inhibitors which include rifampicin, actinomycin D, ethidium bromide, kanamycin, 5‐azauracil, 8‐azaadenine, and rotenone. They were used to study the effect of GA3 and kinetin on the sequential steps in protein synthesis (DNA ‐> RNA ‐> protein), which are variously affected by the inhibitors. The inhibitory effect of actinomycin D on the incorporation can be reversed by GA3 and kinetin, which implies that these two plant hormones act at the transcription level. With ethidium bromide the effect of hormones is not so convincing, though the trend is towards some release of inhibition. The plant hormones have apparently no effect on the incorporation sensitive to other inhibitors studied.GA3 and kinetin can also stimulate the normal and polyadeny‐lic acid [poly(A)]‐directed incorporation of 14C‐labelled lysine into proteins by a mitochondria! preparation, lndole‐3‐acetic acid and 2,4‐dichlorophenoxyacetic acid can only stimulate the normal synthesis, which is not further stepped up by poly (A). The polynucleotide even seems to depress the action of IAA. This anomaly has been discussed.
Iron Deficiency in the Blue‐Green Alga Anacystis nidulans: Fluorescence and Absorption Spectra Recorded at 77°K
Authors: ÖQUIST GUNNAR 
Published: April 2006

AbstractLow‐temperature (77°K) fluorescence and absorption spectra have been determined for whole cells and photosystem I particles of Anacystis nidulans grown in iron‐supplied or iron‐deficient inorganic media. Iron deficiency induces a decrease of F720 relative to F685 and F695 in the fluorescence spectra of both whole cells and photosystem I particles. This change is correlated to a reduction of preferentially the long wavelength absorbing fraction of chlorophyll a. The relative fluorescence intensity at 755 nm is increased by iron deficiency. No significant effects of culture‐age are found in the ratio between the three fluorescence bands (F685: F695: F720) of iron‐supplied A. nidulans.
Automatic Recordings of Action Spectra for Partial Reactions of Photosynthesis
Authors: HALLDAL PER , ÖQUIST GUNNAR , TIMNER LENA 
Published: April 2006

AbstractMethods for automatic recordings of action spectra for partial reactions of photosynthesis are previously described. The present paper elaborates one of the descriptions and gives results from measurements. The method is based upon the recordings of changes in the absorption of certain dyes, which are used as electron acceptors or electron donors to photosynthetic reactions in illuminated chloroplasts or photosynthetic lamellae. By measuring the transmission changes continuously during a wavelength sweep of actinic light, which is corrected for equal numbers of light quanta at different wavelengths, an approximate integrated action spectrum of the selected partial reaction is obtained. A computer program gives the action spectrum after taking the first derivative of the curve and correcting it for changes with time in the rate of the dye reduction (oxidation) and the reverse reactions.The action spectrum for photoreduction of 2,6‐dichlorophenol indophenol and cytochrome c by spinach chloroplasts has a peak at about the same wavelength as the absorption spectrum (677–680 nm). Details in the curves are observed at 650, 663, 673 and possibly at 695 nm. The action spectrum for mammalian cytochrome c oxidation by PSI particles of Anacystis nidulans has a peak at 683 nm (absorption spectrum at 679 nm). Shoulders are observed at 665, 677, 700, and 715 nm.
Permeability and Self‐Induction as Factors in Water Transport through Bean Roots
Authors: KUIPER F. , KUIPER P. J. C. 
Published: April 2006

AbstractWater uptake of root systems of Phaseolus vulgaris was measured in a Scholander pressure cylinder at a constant pressure. Water uptake rises gradually till a steady state is reached after 15 to 60 minutes. This time course can be described as a transport process with the property of a self‐induction. The latter was not affected by temperature. It is concluded that the property of self‐induction is located in the cytoplasm or at the interface between cytoplasm and plasmalemma of the endodermal cells. It is suggested that cytoplasmic streaming controls the time course of water transport.