bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Relationship of Carbohydrates to Cold Acclimation of Hedera helix L. cv. Thorndale
Authors: Steponkus Peter L. , Lanphear F. O. 
Published: April 2006

AbstractWhile both the total sugar content and cold hardiness greatly increased during artificial cold acclimation, no direct parallelism was demonstrated. In fact, plants hardened in the dark exhibited an increase in hardiness during the period when the total sugar content declined, furthermore, while there was evidence for an accumulation of sugars (especially sucrose) incorporation of 14C indicated that all of the isolated fractions were in a dynamic state.Dehardening, paralleled by a large increase in the starch content, was more rapid in the light than in the dark. Furthermore, in stems the sugar content increased after 3 days of dehardening but declined after 7 days. This increase may represent the release of sugars from a previously unextractable form such as a glycoprotein complex.Starvation experiments indicate that photosynthates produced during the cold acclimation period are preferentially used during cold acclimation rather than reserve carbohydrates. This was also indicated by the smaller amount of starch hydrolysis in plants hardened in the light. Thus, while there appears to be a role for carbohydrates in the cold acclimation process, the lack of parallelism between sugar content and hardiness may be interpreted as indicating 1) cold acclimation is not merely an accumulation of sugars or an osmotic effect per se, and 2) under normal conditions, the level of carbohydrates is not limiting the rate or degree of cold acclimation.
Action comparée de la 6‐furfurylaminopurine et de la 6‐(γ, γ‐dimethylallylainino)purine sur la croissance, l'activité peroxydasique, la teneur en chlorophylles et en caroténoïdes
Authors: Caspar Th. , Xhaufflaire A. 
Published: April 2006

Abstract Comparative Effects of 6‐Furfurylaminopurine and 6‐(γ, γ‐Dimethylallylamino) purine on Growth, Peroxidase, Chlorophyll and Carotenoid Content. — 6‐Furfurylaminopurine (FAP) and 6‐(γ, γ‐dimethylallylamino) purine (IPA) both inhibit root growth and cause an increase in peroxidase activity. When used at 10−8 and 10−8M, IPA stimulates elongation of the coleoptile test, at 10−4M both FAP and IPA provoke an inhibition. FAP and IPA maintain a high level in chlorophylls and carotenoids in floating leaves discs. In all these experiments, IPA has thus a higher effect than FAP.
Dependence of Root Growth on Photosynthesis in Populus tremula
Authors: Eliasson Lennart 
Published: April 2006

AbstractHoot elongation of rooted cuttings of aspen, Populus tremula L., was followed on moist filter paper. The time course of root growth during treatments which decrease or interrupt the supply of carbohydrates to the roots was studied.At light intensities below 4000 lux the rate of root elongation was found to berelated to the light intensity over the leaves. In the dark, root growth decreased within 24 hours and the roots stopped growing completely during the second or third day. Excision of the leaves or steam‐killing of the tissue in a stem section below the leaves was followed by root growth stoppage within 24 hours.These results imply that the rate of root growth under certain conditions is determined by the supply of carbohydrates from the leaves.
Effect of Auxin on Cell Wall Degrading Enzymes
Authors: Tanimoto Eiichi , Masuda Yoshio 
Published: April 2006

AbstractThe effect of auxin on the activities of amylase, cellulase, β‐1, 3‐ and/or β‐l, 6‐glucanase and hemieellulase were observed using etiolated barley coleoptile and pea epicotyl internode segments. The activities of β‐1, 3‐ and/or β‐l, 6‐glueanase and hemicellulase of barley were increased by indole‐3‐acetic acid in a 3 hours' treatment. Amylase activity was not influenced by the auxin. Cellulase activity was not detected under the experimental conditions. 2, 4‐Dichlorophenoxyacetic acid increased hemicellulase activity, but not cellulase and amylase activities, in pea epicotyl segments in 3 hours.Fungal β‐1, 3‐glucanase exogenously applied induced the elongation of barley coleoptile segments. The elongation induced by the enzyme was as high as that induced by indole‐3‐acetic acid at least for the first 1 to 3 hours.
The Effect of Temperature Treatments on Growth and the Metabolism of Ribonucleic Acid in Relation to Cell Division and Cell Elongation of Pisum sativum Roots
Authors: Kung Huei‐Kuen , West S. H. 
Published: April 2006

AbstractWe observed the effects of a range of temperatures on root elongation, cell production, total RNA in the root tip, and changes in various nucleic acid fractions in dividing and elongating areas of pea roots. High temperatures affected elongation of roots more adversely than cell production. In the tip section of the root, growth was positively associated with a decrease in the first soluble RNA peak that eluted from a MAK column, and with an increase in ribosomal RNA. There was no similar change in these RNA fractions in the elongating area of the pea root.In pulse type tests sRNA‐1 labeled first and the isotype was depleted upon subsequent growth. The specific activity of sRNA‐1 and the depletion of the radioactivity was not nearly so great in the elongating as in the dividing portion of the pea root.
Isoenzyme Polymorphism in Flowering Plants
Authors: Mäkinen Yrjö 
Published: April 2006

AbstractA total of 21 esterase, 3 acid phosphatase and 2 leucinc aminopeptidase isoenzymes, in addition to peroxidases and catalases, were demonstrated in onion seedlings by starch‐gel electrophoresis. In seedlings two weeks old, the root tip and the differentiated zone show very little enzymatic activity, whereas the secondary roots, hypo‐cotyl and cotyledon are enzymatically very active. These differences are correlated with the intensity of cell division. Some esterase isoenzymes are apparently restricted to root, others to shoot tissues. At pH 8.1, anodically moving peroxidases are totally absent from shoot tissues.A developmental study of esterase isoenzyme patterns indicated that no great differences exist between primary root tips from roots 6–18 mm long and seeds germinated for three days, whereas a sudden decrease in enzymatic activity occurs in root tips after seven days' germination when the roots are about 25 mm long. This coincides with the decrease in mitotic Frequency.Actinomycin D and gamma irradiation decreased mitotic frequency almost to zero but did not significantly affect the esterase isoenzyme pattern in root tips. This shows that the activity of these isoenzymes, at least, is not necessarily dependent on cell division but may well be a prerequisite for it.
On the Physiological Effects of Phloridzin, Phloretin and some Related Substances upon Higher Plants
Authors: Stenlid Göran 
Published: April 2006

AbstractSome dihydrochalcones and related flavonoids were tested Cor their effects upon indoleacetic acid oxidase (mainly from pea roots) and upon oxidative phosphorylation in mitochondria from cucumber hypocotyls. Also their influence upon the growth of wheat roots and upon the absorption of 14C‐labelled sugars and 2, 4‐dichloro‐phenoxyacetic acid in wlieat roots was studied.The dihydrochalcone glucoside phloridzin known for its strong inhibitory effects upon sugar transport in some animal tissues gives no corresponding specific effects in higher plants. Phloridzin and some related dihvdrochalcone glycosides as well as the structurally similar compounds naringenin and 2′, 4, 4′‐trihydroxychalcone are potent stimulators of indoleacetic acid oxidase. Sieboldin, which compared to phloridzin has an additional hydroxyl group (giving an ortho‐diphenolic substitution in the B‐ring) is a strong inhibitor of indoleacetic acid oxidase (10−6M gives about 50 per cent Inhibition). Phloridzin and sieboldin replace each other in different groups of species in the genus Malus.The aglycones phloretin, naringenin and 2′, 4, 4′‐trihydroxychalcone stimulate wheat root growth (especially in the presence of auxins or growth‐inhibilory sugars) and inhibit the absorption of sugars and of 2, 4‐dichlorophenoxyacetic acid. They also inhibit oxidative phosphorylalion and give a distinct uncoupling effect. The glycosides are as a rule less active in all these respects and sieboldin is almost inactive.There is a rather good correlation between uncoupling of oxidative phosphorylation and effects upon root growth, whereas there is no agreement in the details between the effects upon root growth and upon IAA oxidase.
Red Light Effects on Uptake of 14C and 32P into Etiolated Corn Leaf Tissue During Photomorphogenic Leaf Opening
Authors: Steiner A. , Price L. , Mitrakos K. , Klein W. H. 
Published: April 2006

AbstractRed light effects on the uptake of 14C and of 32P was studied by observing leaf sections from 8‐day‐old etiolated corn leaves that were placed on various substrates following a brief exposure to red radiant energy. There was a general increase of 14C uptake over dark levels into all metabolite fractions that were prepared. This is in contrast with results obtained previously in which leaf samples were first floated on substrate and then irradiated (Mitrakos et al. 1967, Price et al. 1965). The latter tests resulted in a general decrease in sugar and starch as well as 14C content of all fractions. However, under both types of experimental conditions the red light effect manifested itself as an increase in hexosemonophosphate turn‐over rate and accumulation of radioactivity in the cell wall polysaccharide fraction. The present data further substantiate the previous work in that they demonstrate the regulatory influence of the hexose pool size on the intermediary metabolism and the manifestation of the phytochrome responses. From the data thus far obtained it cannot be determined as to whether or not phytochrome mediates by controlling phosphorylating activity or through control of specific enzymatic processes that lead to observable cell wall polysaccharide synthesis and leaf unrolling.
A Re‐examination of the Penetration of Nitella Cells by Non‐electrolytes
Authors: Milborrow B. V. , Williams D. A. 
Published: April 2006

AbstractThe increase, followed by culmination and decrease, of biological activity often observed within a homologous series of toxic compounds has previously been explained by assuming that their rate of movement between the lipid cell membrane and the aqueous protoplasm passes through an optimum as the partition coefficients increase progressively. In contrast to this, it has been claimed that direct measurements of the penetration rate of compounds through individual Nitella cells show tbat penetration rates are proportional to partition coefficients.In this attempt to investigate these two opposed hypotheses an analysis of published penetration rate data, obtained with Nitella, showed that the direct penetration measurements were best described by an equation which included a quadratic function of partition coefficient. There is, therefore, no inconsistency between the measurements of penetration by biological activity and by direct measurement. The compounds used in the latter procedure were all relatively hydrophilic and although a maximum rate of penetration was observed tbere was no indication of a subsequent decrease as there were no compounds with high partition coefficients. The correlation of penetration with other physical properties of the compounds is discussed.
Isoenzyme Polymorphism in Flowering Plants III Gel Electrophoretic Methods and Applications
Authors: Brewbaker James L. , Upadhya Mahesh D. , Mäkinen Yrjö , Macdonald Timothy 
Published: April 2006

AbstractGel electrophoretic methods and equipment which were devised or modified for rapid and economic application to angiosperm tissues are described. Staining schedules are outlined that proved effective on a wide variety of tissues for elucidation of isoenzymes with the following activities; eslerase, peroxidase, catalase, leucine amino peptidase, phosphatase, amylase, and glutamic‐oxalacetic‐transaminase. Illustrative applications are discussed.
Effect of Photoperiod on Isoenzymic Composition of Citrus and Poncirus
Authors: Warner Robert M. , Upadhya Mahesh D. 
Published: April 2006

AbstractLong day photoperiod treatments given to Dancy and Clementine tangerines (Citrus reticulata Blanco.), the Mineola tangelo (C. parodisi Macf. × C. reticulata Blanco.) and the Rubideaux trifoliate (Poncirus trifoliata (L.) Raf.) produced 1.5 to 2.5 times the stem area, total linear growth and number of branches compared to short day treatments.Growing shoot tips were snbjected lo etectrophoretic analyses of tbe isoenzymic composition of esterases, teucine aminopeptidases, peroxidases and amylases. Differences were observed in the number and activity of the isoenzymes between the sbort and the long day treated plants of the three Citrus species aiid Hnbideaux trifoliate orange. The possible significance of tbese differences is discnssed in relation to Ihe growth in response to the photoperiodic treatments.
Photoperiodic Responses of Brassica campestris cv. Ceres
Authors: Friend D. J. C. 
Published: April 2006

AbstractThe photoperiodic responses of Brassica campestris L. cv. Ceres were investigated to determine the suitability of this plant for further studies on the spectral require ments for floral initiation. This is a long‐day plant, sensitive to one inductive photocycle on the fourth day from germination. The flowering response increased with the length and intensity of a single period of supplementary light used to extend an 8‐hour daylength and was greatest at 25°C. Application of nitrates retarded floral initiation by about two days under short day conditions, but did not affect the re sponse to one long day. Gibberellic acid induced earlier floral initiation under short day conditions.The photoperiodic response was little affected by omitting the main light period immediately before or after the supplementary light, as long as the intensity of supplementary light was greater than 5000 lux. Short interruptions (5–10 minutes) of a single 16‐hour dark period with high energy red or far‐red radiation did not promote flowering. When given continuously during a single 16‐hour dark period, far‐red radiation was more effective in flower promotion than an equal energy of red.
Inhibitors Interacting with Cytokinins
Authors: Kuraishi Susumu , Kasamo Kunihiro , Tezuka Takafumi , Ushijima Tadahiro , Tazaki Tadayoshi 
Published: April 2006

AbstractCytokinins and gibberellins stimulate the leaf growth of Raphanus sativus L. var. acanthiformis Makino and the germination of tobacco seeds (Nicotiana tabacum L cv. Bright Yellow) in the dark. An SH bahibitor, p‐chloromercuribenzoate, enhanced physiological effects caused by cytokinins, but not those by gibberellins. The same phenomena were observed with amytal and alloxan. Inhibitors of glycolysis, TCA cycle, evtochrome oxidase and oxidative phosphorylation did not show such an enhancement. These results suggest that certain levels of nicotinamide nucleotides or SH in proteins stimulate the action of cytokinins and that the mode of action of cytokinins has close relation to carbon metabolism.
Fluoride Inhibition of Respiration and Fermentation in Cultured Cells of Acer pseudoplatanus
Authors: Givan Curtis V. , Torrey John G. 
Published: April 2006

AbstractLow concentrations of sodium fluoride severely inhibit anaerobic CO2 evolution in Acer pseadoplatanus L. cells but have relatively little effect on aerobic respiration. The insensitivity of respiratory O2 uptake to fluoride is due in part to the fact that fluoride reduces the intracellular pyruvate concentration to only a relatively minor extent under aerobic conditions, although it prevents the several fold increase in endogenous private which is normally brought about by anoxia. The respiratory insensitivity is also ascribable to the existence of a respiratory component which is unaffected by the decrease in endogenous private resulting from fluoride treatment. The extremely severe respiratory inhibition brought about by fluoride plus dinitrophenol is not appreciably relieved by exogenous private, indicating that this inhibition is the result of interference with the aerobic oxidation process per se and is not solely a consequence of glycolytic inhibition.
Enzymatic Maceration of Plant Tissue
Authors: Sato Sitiro 
Published: April 2006

AbstractTissue cells of Vicia faba were separated from the leaf pieces by the pectinase treatment after which the chlorophyll determination method was employed. The separation proceeded at a constant rate for 3 hours', the maximum rate of separation was at pH 5.3. The optimal pH shifted to 5.5 in the presence of 0.001 M 2Na‐ethylenediaminetetraacetic acid (EDTA), which accelerated the separation at pH levels higher than 5.5. The separation was enhanced by NaCl and MgCL2 and delayed by CaCl2 and hypertonicity produced by sugars. Indoleacetic acid (IAA) and naphthaleneacetic acid (NAA) accelerated the separation at physiological concentrations. The rate of separation differed markedly by the age of the leaf and the species which offered the substrate material.
The Effect of CCC and Amo‐1618 on Growth, Catalase, Peroxidase and Indoleacetic Acid Oxidase Activity of Young Barley Seedlings
Authors: Caspar Thomas , Lacoppe Josiane 
Published: April 2006

AbstractBarley seedlings were grown in darkness on filter paper saturated with phosphate buffer or CCC and Amo‐1618 buffered solutions. The effects of CCC and Amo‐1618 on growth, catalase, peroxidase and lAA‐oxidase were studied on coleoptile and primary leaves.Both growth‐retarding chemicals cause an inhibition of growth, Amo‐1618 being more effective than CCC. They have no effect on catalase activity.Increasing concentrations of CCC and Amo‐1618 progressively stimulate peroxidase and IAA‐oxidase activities (Amo‐1618 more than CCC). The enzymatic activity in short‐treated plants is higher than in the corresponding control plants of the same height.It is proposed that CCC and Amo‐1618 exert their effect on the growth of barley by acting on auxin catabolism.
The Role of Calcium and Cell Permeability in the Disease Blossom‐end Rot of Tomatoes
Authors: van Goor B. J. 
Published: April 2006

AbstractResearch was carried out concerning the cell‐physiological backgrounds of the disease blossom‐end rot of tomatoes, which, like bitter pit of apple and lipburn of lettuce, is a Ca‐deficiency disease. In our experiments tomatoes with the least amounts of Ca were attacked by the disease. We estimated the ion permeability of tissues with different Ca levels.Permeability was found to increase with decreasing Ca contents in the tissue. The increase accelerated with the beginning of the disease. The artificial rise in the permeability caused by ether and decenylsuccinic acid resulted in an increased occurrence of the disease.It is probable that the Ca‐deficiency causes the necrosis of the tissue in blossomend rot and that the shortage of calcium among others affects the disorganization of membranes and organells in the cell.
Photosynthesis, Photorespiration and Respiration of Detached Spruce Twigs as Influenced by Oxygen Concentration and Light Intensity
Authors: Poskuta J. 
Published: April 2006

AbstractThe effects of oxygen concentration and light intensity on the rates of apparent photosynthesis, true photosynthesis, photorespiration and dark respiration of detached spruce twigs were determined by means of an infra‐red carbon dioxide analyzer (IRCA). A closed circuit system IRCA was filled with either 1 per cent of oxygen in nitrogen, air (21 % O2) or pure oxygen (100 % O2). Two light intensities 30 × 103 erg · cm −2· s−1 and 120 × 103 erg · cm−2· s−1 were applied.It has been found that the inhibitory effect of high concentration of oxygen on the apparent photosynthesis was mainly a result of a stimulation of the rate of CO2 production in light (photorespiration). In the atmosphere of 100 % O2, photorespiration accounts for 66–80 per cent of total CO2 uptake (true photosynthesis). Owing to a strong acceleration of photorespiration by high oxygen concentrations, the rate of true photosynthesis calculated as the sum of apparent photosynthesis and photorespiration was by several times less inhibited by oxygen than the rate of apparent photosynthesis. The rates of dark respiration were essentially unaffected by the oxygen concentrations used in the experiments. An increase in the intensity of light from 30 × 103 erg · cm−3· s−1 to 120 · 103 erg · cm−2· s−1 enhanced the rate of photorespiration in the atmospheres of 21 and 100 % oxygen but not in 1 % O2. The rate of apparent photosynthesis, however, was little affected by light intensity in an atmosphere of 1 % oxygen.
Root Growth Activity of Barban in Relation to Auxin and Other Growth Factors
Authors: Burström H. G. 
Published: April 2006

AbstractThe effect of barban (4‐Cl‐2‐butynyl‐N‐3‐Cl‐phenylcarbamate) on the growth of roots of wheat seedlings has been studied. In concentrations of 10−7 to 5 · 10−7M barban causes rapid inhibitions of cytokineses and cell elongation, the effects of which are spontaneously reversible. The reversion of the meristem inhibition is enhanced by thymidylic acid and indole‐3‐acetic acid (IAA). Initiation of cell elongation is slowed down or ceases during cytostasis; its reversal, on the other hand, is promoted by IAA and kinetin but inhibited by Fe. The final cell elongation attained is strongly reduced by barban and reversed under transient aberrant elongation. This inhibition and the recovery appear both to be additive to cell elongation actions of auxin and antiauxin but reversed by nucleic acid components. The inhibition of elongation is increased by Fe. The following explanation for this phenomenon is suggested: the primary effect of barban is known to be the blocking of metaphases under anaesthesis; this blocking then leads to reduced activation of IAA, kinetin and other metabolites. Auxin is required for cell divisions and initiation of elongation: the apical root growth equals in this respect that of shoot apices and lateral meristems. Initiation of cell elongation is closely dependent upon metabolites produced in dividing meristematic cells, whereas the limitation of cell stretching is independent of the meristem activity. No explanation is offered for the role of Fe.
Stickstoffgehalt in Blättern von Psychotria mit N‐bindenden Endophyten
Authors: Löhr Erika 
Published: April 2006

Abstract Nitrogen Content in Leaves from Psychotria with Nitrogen‐Fixing Endophytes. — Leaves from Psychotria calva with bacteria along the midrib did not contain more nitrogen than leaves from the surrounding trees. This indicates probably that the nitrogen fixing activity of the endophyte is small or zero.
Resistances to the Diffusion of Gas and Vapor in Leaves
Authors: Gale J. , Poljakoff‐Mayber Alexandra 
Published: April 2006

AbstractConsiderable error may be incurred when the component leaf resistances to gases are calculated from the rates of photosynthesis and transpiration measured for the entire leaf. This is due to the fact that there are two parallel pathways for diffusion — through the upper and the lower leaf surfaces — which in most leaves are asymmetrical. True values for the resistances, and predictions of the results of their modification, have been obtained from separate measurements of the photosynthesis and transpiration via the two leaf surfaces.