bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is the Diageotropic Tomato Ethylene Deficient?
Authors: JACKSON MICHAEL B. 
Published: April 2006

AbstractThe production of ethylene by a mutant form of tomato (Lycopersicon esculentum Mill. cv. Ailsa Craig) with diageotropic shoot growth was compared with that from non‐mutant, upright plants. No difference in the rate of production by segments of petiole or stem apex was observed. The amounts of ethylene produced by excised segments of petiole from diageotropic and upright plants in response to wounding were also comparable.When the roots of either kind of plant were exposed to anaerobic conditions, the production of ethylene increased in the petioles; in ordinary plants this was associated with epinastic curvature, while in diageotropic plants the direction of shoot extension became reorientated from the horizontal to a more upright position. Exogenous ethylene gas had similar effects.These results support the view that the mutant has a modified response mechanism to gravity and to ethylene rather than an abnormally slow rate of ethylene production in the shoot. Since applying inhibitors of ethylene action to non‐mutant, upright plants did not induce diageotropism, endogenous ethylene seems unlikely to play a significant role in maintaining their upright orientation.The roots of both kinds of plant produced large amounts of ethylene, although the rate for diageotropic roots was about 37% less than that of roots from normal plants. Application of indol‐3‐ylacetic acid increased the production of ethylene by all roots but those from mutant plants were less responsive.
Influence of Abscisic Acid on Phosphorus Metabolism and Respiration in Potato Tuber Discs. Comparison with the Cycloheximide Effect
Authors: HOURMANT ANNICK , PENOT MICHEL 
Published: April 2006

AbstractAgeing of discs of potato tuber by incubation in an aerated medium, produces an increase in the rates of respiration and of phosphate uptake. The presence of cycloheximide (CHM) or abscisic acid (ABA) in the uptake medium, does not change uptake by fresh tissue over 3–4 h. On the other hand, CHM causes an inhibition of the rate of uptake by aged tissue although ABA does not. The addition of CHM or ABA to the ageing medium, prevents totally (CHM) or only partially (ABA) the increase in phosphate uptake. The analysis of 32P‐incorporation into the various phosphorylated fractions after 24 h of ageing with CHM or ABA show that CHM induces a large inhibition of the rate of uptake with an almost complete inhibition of 32P‐incorporation into the various phosphorylated fractions. By contrast, ABA produces equal inhibition of 32P labelling of all fractions including all acid‐soluble components. CHM prevents the increase in the rate of respiration, whereas ABA causes a slight stimulation. In both cases, no important effect on ATP content was observed. These results are discussed in terms of a comparison of ABA and CHM actions. They lead to the hypothesis of a specific effect of ABA on the development of the uptake mechanism.
Ethylene Production by Tobacco (Nicotiana tabacum) Callus
Authors: HUXTER TERRY J. , REID DAVID M. , THORPE TREVOR A. 
Published: April 2006

AbstractTobacco callus cultures grown on defined agar‐solidified media produced ethylene in differing amounts, which were related to cultural treatment and age of the callus. There was a close correlation between the rate of ethylene production and growth. In darkness, maximal rates occurred in the third week of growth with ethylene production in the range of 750 nl (callus piece)−1 d−1 (fr. wt. = 1.5 g), and in the light, maximal rates occurred in the first week of growth, 200 nl (callus piece)−1 d−1 (fr. wt. = 200 mg). Growth was also correlated with ethylene production when the latter was altered by exposure of the callus to inhibitors of ethylene synthesis, L‐canaline, benzyl isothiocyanate, and 3,5‐diiodo‐4‐hydroxy‐benzoic acid. No correlation was found following treatment with AgNO3, a presumptive inhibitor of ethylene action. The inhibition of growth and ethylene production by L‐canaline was partially reversed by gassing the cultures with ethylene (1 μl/1). A mercuric perchlorate sink had no significant effect on growth. A possible relationship between ethylene evolution and growth is discussed.
The Effect of Some Protein and Non‐Protein Amino Acids on the Growth of Cladosporium herbarum and Trichothecium roseum
Authors: SIMOLA LIISA KAARINA , LÖNNROTH KAIJA 
Published: April 2006

AbstractThe effect of ten amino acids as the sole nitrogen source for the growth of Cladosporium herbarum (Link.) Fr. and Trichothecium roseum (Bull.) Link. was studied in order to clarify the fungus‐host plant relationship. Special attention was paid to some rare non‐protein amino acids of legumes. The best nitrogen sources for both fungi were γ‐aminobutyric acid, arginine, serine and proline. Cladosporium could use homoarginine and canavanine, but these two amino acids were not used by Trichothecium when each was given as the only nitrogen source. Both fungi utilized ornithine, homoserine and a,γ‐diaminobutyric acid to a limited extent. Pipecolic acid was not growth promoting. The growth‐retarding effects of rare non‐protein amino acids (homoarginine, canavanine, a,γ‐diaminobutyric acid and pipecolic acid) were usually reversed by higher concentrations of their normal analogues. It is possible that rare non‐protein amino acids may slightly protect the host plant against fungal infections, but there are clear differences between fungi in their reaction to non‐protein amino acids.
Growth Cycles in Lemna gibba Cultures and Their Effects on Growth Rate and Ultrastructure
Authors: TILLBERG E. , HOLMVALL M. , ERICSSON T. 
Published: April 2006

AbstractA long‐established axenic culture of Lemna gibba G3 was maintained in exponential growth phase under controlled conditions. Weekly analyses for 2 years showed that the individual plants of the Lemna gibba clone fluctuated between two forms. One extreme consisted of plants light in weight, small in size, and with a high relative growth rate (RGR), the other of heavy, large, and more slowly growing plants. At intervals plants having intermediate characteristics dominated in the stock culture. Indication of an annual growth‐cycle was also found.The magnitude of growth response (weight, RGR, area, and dry matter content) after treatment with abscisic acid (ABA), 6‐benzylaminopurine (BAP), and a combination of the two was different for low‐weight and heavy plants. The heavy plants were more sensitive to ABA and BAP treatment than the low‐weight ones. The accumulation of starch was least in small untreated plants and greatest in ABA treated plants. Large electron transparent globules were found in the chloroplasts of the ABA treated plants and in heavy plants regardless of how they had been treated.The different physiological and ultrastructural characteristics of the two forms of Lemna plants probably reflect an ageing‐rejuvenation cycle. Emphasis is placed on the importance of this cycle when Lemna is used as a model plant in physiological experiments.
An Analysis of the Role of Potassium in the Growth Effects of Cytokinin, Light and Abscisic Acid on Cotyledon Expansion
Authors: GREEN JEROME F. , MUIR ROBERT M. 
Published: April 2006

AbstractHigh external concentrations of potassium were found to promote light‐induced growth of cucumber cotyledons similarly to the effects previously observed for the growth induced by cytokinins. At 40 mM KCl, the response to white light was 3.6 times greater than in the absence of KCl. The promotive effect of calcium on the growth induced by cytokinin was not observed for light. In 40 mM KCl and 10 mM CaCl2, the responses to light and cytokinin were similar and additive. Both near‐red and far‐red light induced growth at low intensities. The response to white light at low intensities was sharply increased with higher intensity up to 24 μE m‐2 s‐1 and only slightly increased above that level.Abscisic acid was found to inhibit strongly the responses to light and cytokinin. The inhibition was greater in the presence of KCl than in its absence and thus abscisic acid appeared to inhibit primarily by its interference with potassium uptake. Kinetic analysis found the light response promoted by potassium to be inhibited competitively by abscisic acid, with the light response having a Km of 34 mM KCl and a Vmax of 115 mg/cotyledon × 4 days. The inhibition of the cytokinin response by abscisic acid was noncompetitive in relation to potassium, having a Km of 1 mM KCl and a Vmax of 50 mg/cotyledon × 4 days.It is suggested that cytokinin, light and abscisic acid have primary properties affecting membrane permeability and that their interaction with potassium is an explanation of many similarities between light and cytokinin responses and their inhibition by abscisic acid.
Starch Synthesis in Developing Potato Tubers
Authors: HAWKER J. S. , MARSCHNER H. , KRAUSS A. 
Published: April 2006

AbstractThe activities of enzymes involved in starch metabolism were measured at intervals during tuberization and the early stages of tuber growth in Solanum tubersum grown in water culture under controlled environmental conditions. Starch synthase, ADPglucose pyrophosphorylase, UDPglucose pyrophosphorylase and phosphorylase activities all increased during tuber development, the most pronounced increases occurring in the activities of ADP‐glucose pyrophosphorylase and phosphorylase. The activity ratio ADPglucose pyrophosphorylase/phosphorylase was lowest in slow growing tubers and hightest in fast growing tubers. In addition, high sugar concentrations in fast growing tubers and low sugar concentrations in slow growing tubers suggested that enzyme levels might be influenced by sugar concentration. The activities of starch synthase, phosphorylase and ADPglucose pyrophosphorylase were increased 2–2.5 fold by the presence of 100 mM K+. It is concluded that the major enzyme changes occur as a consequence of tuber initiation and that starch accumulation is controlled, at least in part, by the activities of ADPglucose pyrophosphorylase and phosphorylase.
A Definition of Optimum Nutrient Requirements in Birch Seedlings
Authors: INGESTAD TORSTEN 
Published: April 2006

AbstractBirch seedlings (Betula verrucosa Enrh.) were grown in nutrient solutions with pH varied in the range 2.5 to 6.8 or temperature varied in the range 2.5 to 35°C. The criteria for maximum growth previously established for birch seedlings were used and maintained by means of automatic pH and conductivity titrations with stock solutions containing the optimum nutrient proportions. Both nitrogen sources, NH4 and NO3, were present in the solutions. Growth rate was maximum or close to maximum between pH 4.0 and 6.8, whether kept at a specific level or allowed to vary between the extremes. At pH 3.5 and lower, the calcium uptake was decreased and root damage was observed. The seedlings has also a high dry matter content and obviously an unsatisfactory water balance. pH 2.5 was rapidly lethal. Growth rate was linearly correlated with solution temperature up to 20°C. Temperatures above 30°C, especially in the range 32.5 to 35°C, resulted in rapid decrease in growth rate. The nutrient contents in the seedlings were strongly affected by solution temperature in the low as well as in the high range when expressed on a dry weight basis. However, this effect was almost entirely attributable to changes in dry matter content. When expressed on a fresh weight basis, nutrient uptake and nutrient status of the seedlings appeared to be optimum throughout, although a variation remained since the varying dry matter content is included in the fresh weight basis. The results indicate, in agreement with the literature, that disturbed water uptake and water balance is the way in which growth is affected by root medium temperature. Similarly, extremely low pH levels in the nutrient solution meant root damage, although birch seedlings appear comparatively insensitive to pH variations. Thus, the growth technique used supplied the seedlings with adequate nutrients, so that the criteria used in the definition of nutrient requirements in birch seedlings are valid within wide ranges of solution pH and temperature; and other factors than nutrition determine growth.
Alterations in Endogenous Levels of Gibberellin‐like Substances during Germination of Phaseolus vulgaris Seeds
Authors: VON SCHIRACH‐SZMIGIEL LINDA 
Published: April 2006

AbstractThe endogenous gibberellin‐like substances were determined in mature dry and germinating bean seeds, Phaseolus vulgaris L. cv. Alabaster. Methanol extracts were partitioned against ethyl acetate and butanol at neutral and acid pH. Each phase was individually chromatographed on a silica gel column. The gibberellin activity was measured with the Tan‐ginbozu dwarf rice micro‐drop bioassay. Each extract was tested in two dilutions. Extracts from dry seeds showed the highest gibberellin activity, largely attributable to ethyl acetate‐soluble substances. The activity was considerably reduced in extracts from seeds imbibed for 1 day. Gibberellin‐like substances soluble in butanol appeared in extracts from seeds soaked for 1 or more days.
Zinc Effects on Growth, Pigmentation and Antibacterial Activity of Monascus purpureus
Authors: BAU YUN‐SUN , WONG HIN‐CHUNG 
Published: April 2006

AbstractGrowth, pigmentation and antibacterial activity of Monascus purpureus Went (starch fungus) were affected by zinc. Zinc at concentrations of 2 × 10‐3M and 3 × 10‐3M nearly stopped the growth, pigmentation and antibiotic production of both wild type and strain NI IS in liquid medium. Relatively vigorous growth, high pigment production, and strong antibacterial activity of NIIS still occurred on solid medium with the same zinc concentrations. Wild type was hardly affected by zinc concentrations lower than 2 × 10‐3M. The growth of strain NI IS was significantly inhibited even by 5 × 10‐5M zinc, but pigment production and antibacterial activity were highly promoted by 5 × 10‐5M zinc. Increase of glucose concentration also promoted pigment and antibiotic productions of strain NI IS. Glucose effects were intensified as 1 × 10‐3M zinc was added. Zinc may act as a growth inhibitor and concomitantly as a stimulant for glucose uptake and for the synthesis of metabolites such as pigments and antibiotics.
Phytochrome Pelletability in Barley
Authors: ROTH‐BEJERANO NURIT , KENDRICK RICHARD E. 
Published: April 2006

AbstractPhytochrome pelletability in the 1000 g and 20,000 g pellet from crude homogenates of etiolated Hordeum vulgare L. cv. Ark Royal primary leaves is enhanced by red light in vivo and in vitro. Red enhanced phytochrome pelletability appears different in the 1000 g and 20,000 g pellets after red light in vivo, being irreversible by subsequent far red light in the latter. Mg2+ concentration in the range 1–20 mM has no effect on red enhanced phytochrome pelletability. The enhancement of pelletability is reduced by low pH and high 2‐mercaptoethanol concentration, conditions which lead to a high level of pelletability of the far red absorbing form of phytochrome. Washing these pellets at high pH or low 2‐mercaptoethanol concentration reveals the red enhancement of pelletability. The results are discussed in terms of a possible two point attachment of phytochrome to membranes.
Fatty Acid Synthesis in Hydrilla Chloroplasts
Authors: BHATIA I. S. , AHUJA K. L. , SUKHIJA P. S. 
Published: April 2006

AbstractThe rates of carboxylation, photophosphorylation and acetate incorporation have been compared in the intact and broken chloroplasts of Hydrilla verticillata Royle leaves in the presence and absence of certain inhibitors and metabolites. The intact chloroplasts showed low rates of photophosphorylation, high rates of carboxylation, and exhibited normal capacity for fatty acid biosynthesis. In broken chloroplasts a drastic decrease was observed in the rates of carboxylation and acetate incorporation. However, the rate of photophosphorylation was considerably increased. In the presence of light, inhibitors such as iodoacetamide, arsenite and sodium azide decreased the photophosphorylation rate. F‐1,6‐di‐P and PGA stimulated CO2 fixation rate. In the absence of artificial light, inhibitors such as sodium arsenite, gluconate‐6‐phosphate, sodium azide and iodoacetamide decreased the rate of CO2 fixation. CoA, ATP, G‐6‐P, F‐1,6‐di‐P Stimulated the synthesis of fatty acids. Exogenous supply of ADP. NADH, NADP and NADPH did not stimulate fatty acid biosynthesis probably because these compounds could not gain entry into the chloroplasts. Light was necessary for the in vitro fatty acid biosynthesis.
Distribution of Soluble 14C‐Labelled Assimilates as Related to Distribution of 14C‐Benzyladenine in Shoot Tips of Hedera helix
Authors: CLARK JAMES R. , HACKETT WESLEY P. 
Published: April 2006

AbstractThe relationship between benzyladenine and assimilate distributions in shoot tips of English Ivy (Hedera helix L.) was studied. Exogenous applications of benzyladenine resulted in small amounts of the hormone moving to the apical meristem. The large part of the recovered benzyladenine was found in the young leaves of the shoot tip.Benzyladenine increased the amount of 14C‐labelled assimilates in the shoot tip, but the distribution pattern of those assimilates within the tip was like that of the untreated control.
Oxygen Consumption Stimulated by δ‐Aminolevulinic Acid in Darkness and during Irradiation of Dark Grown Wheat Leaves
Authors: CARLSSON ROLF , SUNDQVIST CHRISTER 
Published: April 2006

AbstractDark grown wheat leaves (Triticum aestivum L. cv. Starke II Weibull), treated with δ‐aminolevulinic acid in darkness, showed an increased oxygen uptake as measured by a Warburg method. The production of CO2 was also increased in darkness, giving an RQ ≅ 1. The increased respiration was dependent on the treatment time as well as on the concentration of the δ‐aminolevulinic acid. Potassium cyanide suppressed both the normal and the increased respiration. The treatment with δ‐aminolevulinic acid caused accumulation of high amounts of protochlorophyllide. Levulinic acid suppressed the increased oxygen uptake as well as the protochlorophyllide accumulation in δ‐aminolevulinic acid treated leaves. Irradiation rapidly decreased the protochlorophyllide content with a simultaneous increase in oxygen uptake over the dark value. The peak value of the increase in oxygen uptake was reached after about 5 min. The light induced oxygen uptake was dependent on the amount of PChlide present at the onset of irradiation. Also the CO2 production was increased during the first minutes of irradiation but soon fell under the buffer control value. Neither potassium cyanide nor heat denaturation affected the oxygen uptake in light in contrast to the effect on the CO2 production, which was blocked by heat denaturation. The increased oxygen uptake in light initially seems to be a purely photochemical process leading to a release of CO2, which release is probably an enzymatic process induced by the photo‐oxidative decomposition of pigment.
Influence of Cycloheximide and Actinomycin D on Initiation and Early Development of Adventitious Roots
Authors: OPPENOORTH J. M. 
Published: April 2006

AbstractFrom leaf cuttings of the bean Phaseolus vulgaris L. adventitious roots form on the petiole. This root formation is stimulated by treatment with auxin. Simultaneous or subsequent application of cycloheximide irreversibly inhibited dedifferentiation, so that root production was completely prevented. The effects of actinomycin D application depended upon the stage of development of the root primordium. Cells in the first stage of dedifferentiation were extremely sensitive. When actinomycin D was applied later than 6 h after cutting, its inhibiting effect gradually diminished.It is concluded that an actinomycin D‐sensitive process occurring early in dedifferentiation is crucial for root initiation. A second, less actinomycin D‐sensitive process occurring later in dedifferentiation is required for the further development of the root primordium. During the initiation and development of the root primordium protein synthesis is required.
Starch Measurement in Plant Tissue Using Enzymatic Hydrolysis
Authors: HAISSIG BRUCE E. , DICKSON RICHARD E. 
Published: April 2006

AbstractThis work explored completeness of starch hydrolysis in situ in relation to degree of gelatinization, starch content of tissue, evailable enzyme activity, and time allowed for hydrolysis. Maximum hydrolysis of starch in lyophilized red oak (Quercus rubra L.) root tissue with purified Diazyme (amyloglucosidase) or Clarase (Takadiastase) required high enzyme activity (2.4 U Diazyme or 48 U Clarase per mg starch). Results suggested that at least 70 U Clarase or 5 U Diazyme should be used per mg starch in routine analyses. Neither prolonging gelatinization (more than 15 min) nor hydrolysis (more than 24 to 48 lh) offset inadequate starch hydrolysis caused by insufficient enzyme activity. Starch was completely hydrolyzed in situ after 48 h without gelatinization by 5 U of Diazyme per mg starch. Tissue weight (5 to 100 mg) had no effect on starch hydrolysis by sufficient enzyme. Methanol: chloroform: water (12:5:3 by volume) freed tissues of solubles before starch hydrolysis. No interference with the glucose oxidase analysis of hydrolysates was encountered. In addition, the pigment free methanol–water fractions (soluble sugars, amino acids, organic acids) and chloroform fractions (lipids and pigments) were available or further analysis. Results obtained with red oak were verified with issue from other species such as jack pine (Pinus banksiana lamb.) and white spruce (Picea glauca (Moench) Voss). The resulting technique simply and reliably measured less than 5% starch in 5 mg lyophilized tissue, with a minimum of sample manipulation.
Hormonal Modulation of the Oscillatory System Involved in Polar Transport of Auxin
Authors: WODZICKI TOMASZ J. , WODZICKI ALINA B. , ZAJACZKOWSKI STEFAN 
Published: April 2006

AbstractThe amount of natural auxin collected in agar as a result of basipetal efflux from the cambial region of successive short sections of pine stem varies so that a wave‐like pattern is formed. The wave‐length is several times longer than the cell length in the cambial region, suggesting the existence of a supracellular oscillatory system, which forms a morphogenic field in the stem tissues, The amplitude of the auxin wave is amplified by apical application of IAA to the longer stem sections, particularly at she time of spring initiation of cambial activity. The wave of auxin disappears after simultaneous apical application of IAA and ABA. The modulatory effects of IAA and ABA are translocated along the investigated stem sections faster than known transport velocities of IAA molecules. This fact is considered as evidence of apical control of the morphogenic field by way of influence upon a supracellular system of conjugated oscillators in the tissue.
A System Approach to Fluorescence Induction in Green Leaves
Authors: KLOCKARE BIRGITTA , BERNT MELØ THOR ,   with the participation of, JOHNSSON ANDERS 
Published: April 2006

AbstractIntact green oat leaves (Avena saliva) were irradiated with modulated exciting light. Ai the application of initial square pulses of exciting light, the fluorescence induction pattern will change, but after some repeated pulses the fluorescence response pattern stabilizes and becomes identical. This periodic stimulation gave a better resolution of the two peaks constituting the fast fluorescence transient (the DPS region) compared to a single light pulse. The first peak could be depressed by weak light of wavelengths up to about 740 nm, given between the intense light phases of the pulse, while this treatment did not alter the second peak. The intensity of the higher light level of the pulse as well as the frequency were systematically varied. The results are tentatively rationalized in the form of sequential relaxation processes within the frame of the Hill‐Bendull scheme, leading to the possibility of two substances, one belonging to Photosystem II and the other to Photosystem I. underlying the two peaks in the DPS region of the fluorescence induction curve.