bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability of the Indolo‐α‐Pyrone Fluorescence Method for Indole‐3‐acetic Acid Determination in Crude Plant Extracts
Authors: ELIASSON LENNART , STRÖMQUIST LARS‐HELGE , TILLBERG ELISABETH
Published: April 2006

Indole‐3‐acetic acid (IAA) contents in plant extracts were determined spectrofluorometrically after conversion of the compound into indolo‐α‐pyrone. The method is sensitive and accurate and showed good reproducibility. The values obtained by this method corresponded well with those obtained with the Avena coleoptile straight‐growth assay.

Impurities in extracts often cause various difficulties. Colored compounds influence the readings and may even make indole‐3‐acetic acid determination impossible by strong quenching of the fluorescence light. Insoluble compounds can be formed in the reaction and cause increased opalescence and light scattering which interferes with the fluorescence measurements. The necessities for the method to be reliable are that the insoluble compounds are removed or brought into solution and that the exciting light is sufficiently monochromatic.

Indolo‐α‐pyrone is fairly stable in the dark but is rapidly broken down by UV radiation. This decay may be used as a check to see if the measured light represents fluorescence of indolo‐α‐pyrone.
Fatty Acid and Chlorophyll Levels of Coastal Bermudagrass during the Day and during Maturation
Authors: CHAPMAN GLENN W. , ROBERTSON JAMES A. , BURDICK DONALD
Published: April 2006

Lipids were extracted from fresh, field‐grown coastal bermudagrass (Cynodon dactylon (L.) Pers.) and the fatty acids determined by gas chromatography. Total fatty acid levels (dry weight basis) increased during the day and reached a single maximum at sunset in 2‐week‐old grass; whereas, in older grass, the fluctuations in fatty acid levels showed two maxima. The first maximum occurred 4 h after sunrise and the second maximum occurred at sunset. Total fatty acid levels, based on dry weight, decreased during the first 6 weeks of growth and changed very little after an additional 4 weeks' growth in bermudagrass leaf blades. Chlorophyll levels (dry weight basis) continuously decreased during the entire growth period (10 weeks). Chlorophyll alb ratios increased at sunset in 2‐ and 6‐week‐old grass, but this ratio did not change during the day in subsequent growth stages. The results of these experiments show that stages of maturity affected fatty acid fluctuations during the day as well as total fatty acid and chlorophyll levels in Coastal bermudagrass leaf blades. Chlorophyll alb ratios varied independently of fatty acid levels.
Role of Photosynthetic Electron Transfer in Light Activation of Calvin Cycle Enzymes
Authors: CHAMPIGNY MARIE‐LOUISE , BISMUTH EVELYNE
Published: April 2006

The effect of light in activating fructose‐1,6 biphosphate phosphatase (E.C. 3.1.3.11), sedoheptulose‐1,7, biphosphate phosphatase (E.C. 3.1.3.11), ribulose‐5 phosphate kinase (E.C. 2.7.1.19), ribulose‐1,5 biphosphate carboxylase (E.C. 4.1.1.39) and (NADPH) glyceraldehyde‐3 phosphate dehydrogenase (E.C. 1.2.1.13) in intact spinach chloroplasts in the presence of antimycin A, tetramethylethylenediamine (TMEDA) or chlorophenyl‐1,1‐dimethylurea (CMU) was examined. Antimycin A and TMEDA were added as stimulating agents for photosynthetic electron transfer in intact chloroplasts while CMU was added for its inhibitory characteristics.

Light exerted its control through the mediation of the photosynthetic electron transfer. Antimycin A and TMEDA promoted the light activation. CMU nullified the light activation as well as the stimulatory effect of antimycin A and TMEDA.

Thus the control by light of the activities of the Calvin cycle enzymes involves a reduced agent formed by the photosynthetic electron transport chain. From the presently available evidence, it seems appropriate to hypothesize that the light activation of the enzymes is not a single mechanism. In fact three types of enzymes can be distinguished: Ru‐5 P kinase and (NADPH) G‐3 P dehydrogenase, maximal activation of which appears within the first minute of illumination and is promoted by antimycin A and by TMEDA; F‐1,6 P2 phosphatase and S‐1,7 P2 phosphatase, ferredoxin‐dependent enzymes, activation of which is slightly slower but is also promoted by antimycin A and by TMEDA; finally Ru‐1,5 P2 carboxylase, activation of which is still slower and characterized by the absence of any response to antimycin A as well as to TMEDA.
Relationship between Water Potential and Leaf and Inflorescence Initiation in Helianthus annuus
Authors: MARC J. , PALMER J. H.
Published: April 2006

The total number of leaves produced by the primary stem of Helianthus annuus L. cv. Pole Star and cv. Peredovik, was reduced from 29 leaves to 21–22 leaves when water stress ranging from −2000 to −3000 kPa was imposed over the period from day 10 to day 20 after sowing, by withholding water from the soil. Extending the stress period by 10 days did not cause any further significant reduction in leaf number. Examination of the shoot apex showed that the leaf initiation rate was depressed by low water potential, the greatest effect occurring in the range 0 to −1000 kPa. It was established that inflorescence initiation commenced about 18 days after planting in control plants and this was delayed by only about 4 days by low water potentials in the range −1000 to −3000 kPa.
The Effects of Dehydration‐Rehydration Cycles on Protein Synthesis of Black Locust Seedlings
Authors: BRANDLE JAMES R. , HINCKLEY THOMAS M. , BROWN GREGORY N.
Published: April 2006

Protein synthetic activity of polysomes isolated during dehydration‐rehydration cycles of black locust seedlings (Robiniapseudoacacia L.) was investigated. Polysomes of black locust seedlings were reduced by only 20% during water stress and were capable of incorporating 3H‐leucine into peptide chins. RNase activity increased during stress and declined following irrigation. The presence of a protective mechanism is suggested which, if present in other drought hardy species, could help to explain the ability of these species to withstand various levels of water stress.
Changes in Glycolate Oxidase and Glyoxylate Reductase in Quercus robur Infected by Microsphaera alphitoides
Authors: HEWITT H. G. , AYRES P. G.
Published: April 2006

Leaves of Quercus robur L. were infected with conidia of Microsphaera alphitoides Griffon and Maublanc. Crude enzyme extracts of healthy and infected tissue, taken during a 7‐day experimental period, were assayed, using spectrophotometric and manometric techniques, for glycolate oxidase, NAD‐ and NADP‐glyoxylate reductase activities. After 2 days, extracts from infected tissue contained significantly higher activities of glycolate oxidase and NAD‐glyoxylate reductase than extracts from controls, but the activity of NADP‐glyoxylate reductase, after an initial rise, was significantly reduced below that in control extracts. The reduction in glycolate oxidase activity may be partly due to a deficiency in flavin mononucleotide in infected tissue. A possible connection between the reduction in flavoprotein enzyme activity, photorespiration and susceptibility to infection is described.
Environmental Effects on Transpiration and Leaf Water Potential in Avocado
Authors: STERNE RICKIE E. , KAUFMANN MERRILL R. , ZENTMYER GEORGE A.
Published: April 2006

A field study was conducted to determine how atmospheric and edaphic conditions influenced the water relations of avocado trees (Persea americana Mill. cv. Bacon). With high and low levels of incident photosynthetically active radiation (PAR, 400–700 nm wave length), and either wet or dry soil, leaf conductance decreased as the absolute humidity difference from leaf to air increased. For any water stress treatment, conductance was higher at high PAR than at low PAR. Both conductance and transpiration were higher in well‐watered trees than in stressed trees, and in prestressed trees levels were intermediate to unstressed and stressed trees. A model for water flux through the soil‐plant‐atmosphere continuum was used to examine the relationship of leaf xylem pressure potential to transpiration in well‐watered trees and in trees stressed by dry soil. There was a close linkage between leaf xylem pressure potential and transpiration in unstressed and previously stressed trees with high or low PAR, i.e. similar potentials occurred with equivalent transpiration regardless of previous treatment or time of day. In stressed trees, xylem pressure potential was lower than in unstressed trees both during the day and night, and at a given transpiration rate the potential was lower after 1400 h than before that time. The model indicated that in stressed trees xylem pressure potential was uncoupled from transpiration, presumably because of altered resistance in the soil‐root portion of the transport system.
Spectral Properties of Juvenile and Adult Leaves of Piper betle and Their Ecological Significance
Authors: BRUNNER U. , ELLER B. M.
Published: April 2006

Juvenile and adult leaves of Piper betle L. were shown to have different spectral properties. A computer model was used to calculate the temperature of these leaves taking the energy balance approach. At high values of solar radiation, juvenile leaves with lower absorptivity in the visible and the near infrared show markedly lower temperatures than mature leaves. There is an ecological effect of high and low leaf temperatures on heat load and water stress.
The Effect of a Quaternary Amine (Aliquat 336) on Growth and Photosynthesis of the Green Alga Chlorella emersonii, and the Effect on Photosynthesis in Isolated Spinach Chloroplasts
Authors: EGNÉUS HANS , BLANCK HANS
Published: April 2006

A quaternary amine, Aliquat 336, inhibits the growth of the green alga Chlorella emersonii, 14C‐fixation of the alga is also inhibited. The effect and the site of action of the compound was studied by using isolated spinach chloroplasts. The carbon dioxide dependent oxygen evolution of the chloroplasts is inhibited directly upon the addition of the amine and the oxygen evolution is replaced by an oxygen uptake. By investigating some electron transport reactions in the chloroplasts we were able to show that Aliquat 336 affects the electron transport on the level of photophosphorylation. The results from the in vivo and the in vitro experiments thus show that the quaternary amine affects the photosynthetic process.

Aliquat 336 is a solvent extractant used in several industrial processes for extraction of metals from aqueous solutions. Aliquat 336 could be considered a presumptive water pollutant as the compound could enter a recipient water body and thus affect photosynthesis.
Inhibiteurs non acides et dormance embryonnaire chez Taxus baccata
Authors: LE PAGE‐DEGIVRY MARIE‐THÉRÈSE
Published: April 2006

Non‐acidic inhibitors and embryo dormancy in Taxus baccata L.

Embryo dormancy of Taxus baccata is eliminated when the embryos are continuously kept in sterile nutritive liquid medium. After 3 weeks of culture, an important non‐acidic inhibitory complex can be extracted from this liquid medium. At least three substances are involved: two pigments and a compound with some properties that suggest xanthoxin. These substances are neither found in embryos taken directly from the seeds, nor in liquid medium after 8 days of culture, which is the time necessary and sufficient to allow germination after transfer on agar medium. Such behaviour is quite different from that of ABA previously studied and indicates that these non‐acidic inhibitors appear late during the culture and are not directly involved in embryo dormancy.
The Association between Soil and Xylem Water Potential, Leaf Resistance, and Abscisic Acid Content in Droughted Seedlings of Douglas‐fir (Pseudotsuga menziesii)
Authors: BLAKE JOHN , FERRELL WILLIAM K.
Published: April 2006

During progressive stages of drought and subsequent recovery through rewatering, foliage of 2‐year‐old seedlings of Douglas‐fir was sampled for water potential, stomatal resistance, and abscisic acid content (ABA). Simultaneous measurements of soil matric potential were also made. There was a rapid rise in stomatal resistance in the range of 1500–2000 ng ABA g−1 dry weight of foliage corresponding with a plant water potential of –10 to –12 bars. Soil matric potential seemed more closely associated with ABA increase than did plant water potential. After rewatering, seedlings returned to normal ABA levels within 6 days.
Glycolipid Degradation in Leaves of the Thermophilic Cucumis sativus as Affected by Light and Low‐Temperature Treatment
Authors: DE KOK LUIT J. , KUIPER PIETER J. C.
Published: April 2006

Treatment of Cucumis leaf discs with light and low temperature (1°C) resulted in degradation of the total lipids. In addition, a decrease of the linolenic acid content of the glycolipids of leaves and leaf discs took place while at the same time an increase in the content of unidentified degradation products from the glycolipids was observed. The decrease of the linolenic acid content was not due to galactolipase activity, since no monogalactosyl diglyceride acyl hydrolase activity was found. Dark and low temperature did not alter the fatty acid composition. Blue light and low temperature resulted in a decrease of the linolenic acid content, while yellow‐, red‐ and far red light in combination with low temperature were ineffective.
Callus and Plantlet Regeneration from Cell Cultures of Ladino Clover and Soybean
Authors: OSWALD T. H. , SMITH A. E. , PHILLIPS D. V.
Published: April 2006

The auxin to cytokinin ratios are described for promoting growth in the in vitro cultures of soybean (Glycine max (L.) Merr. cv. Bragg) and perennial clover (Trifolium repens L. cv. Regal Ladinc). Callus growth was induced on somatic tissue with 50:1 auxin to cytokinin (w/w) ratio. A 5:1 ratio served for initiation of cell suspensions from callus and for subsequent growth of callus from cells in suspension. A 1:2 ratio served for regeneration of buds and plantlets from the callus grown from cells. Although (2,4‐dichlorophenoxy) acetic acid was the auxin for suspension and regenerative cultures, (2,4,5‐trichlorophenoxy)acetic acid was the more effective auxin for initiation of callus on somatic tissue. All cultures were grown with 6‐furfurylaminopurine as the cytokinin.

The phytohormones strongly influenced the rates of culture growth, but determination of culture type was augmented by dl‐alpha tocopherol acetate and iron. Tocopherol and a relatively high complement of iron promoted growth of juvenile cultures, whereas low level of iron and absence of tocopherol favored growth to comparatively more differentiated cultures. Without tocopherol, no callus formed on somatic tissue during the allotted period of incubation. Tocopherol plus a complement of low iron enabled growth of callus on rapidly growing somatic tissue. A high level of iron enabled comparatively more callus growth but suppressed growth of somatic tissue. In suspension cultures tocopherol and a high iron level enhanced dispersion of cells. A low iron complement in the absence of tocopherol induced growth of callus from cells and subsequent regeneration of buds and plantlets from the callus.
Study of the Efficiency of Hydrasyl as an Antitranspirant with an Isotopic Method
Authors: FERRON F. , COSTES C.
Published: April 2006

The antitranspirant efficiency of Hydrasyl varies when it is sprayed over the blade surface of different plant species. The efficiency index of Hydrasyl was obtained by comparing the enrichment of tritium in water of a treated blade with that in a non‐treated blade. The variability of the results depends on the specific regulation of water loss within the plant (physiological parameter) or on the “wettability” qualities of the cuticle (morphological parameter). The study brings to light the limits in the use of an antitranspirant.
Utilization of Exogenous Carbohydrates for Tube Growth and Starch Synthesis in Pine Pollen Suspension Cultures
Authors: NYGAARD PER
Published: April 2006

Pine pollen (Pinus mugo) grown in suspension cultures readily utilize exogenous carbohydrates for tube growth and starch synthesis: these processes are not influenced by β‐indolylacetic acid, gibberellic acid, kinetin and abscisic acid. It appears that the free sugars of the female gametophyte, namely sucrose, raffinose, and stachyose and their monosaccharide constituents, are the best substrates for growth and polysaccharide synthesis. The oligosaccharides are hydrolysed to their monosaccharide constituents before they are taken up. A preferential uptake of fructose is noted. Non‐metabolizable sugars are not taken up. The data presented establish that tube growth, except for the initial growth phase, can be determined by the availability of exogenous carbohydrates.

Measurements of some of the key enzymes in carbohydrate metabolism show that the enzymes were present in the ungerminated pollen grain, and that the enzyme activity increased severalfold during tube growth. The increase in enzyme activity was prevented if inhibitors of protein synthesis were present in the medium.
Nitrate Reduction in Different Grass Species
Authors: DUSKY JOAN A. , GALITZ DONALD S.
Published: April 2006

Optimal extraction conditions, assay conditions, and levels of nit rate reductase activity (NRA) were determined for eight forage grass species adaptable to growing conditions in western North Dakota. Optimal pH for extraction of the enzyme nitrate reductase (NADH: nitrate oxidoreductase) for these species ranged from 7.0 to 9.5, whereas assay pH was 7.6 in all eight species. Substrate concentrations ranged from 1.0 to 10.0 mM for maximum NRA with higher concentrations (100 mM) significantly inhibiting NRA. The enzyme was NADH2 (0.1 to 0.2 mM for maximum activity) specific. Enhancement of maximum activity with the addition of cysteine during extraction was species dependent; six species required high cysteine concentrations between 5 mM and 10 mM and one species required only a 2.5 mM concentration. The degree of sulfhydryl protection offered by cysteine also varied. Comparisons were made between in vivo and in vitro assay methods. Ratios of in vitro to in vivo NRA ranged from 2.2. to 10.8. Use of bovine serum albumin as a protein stabilizer during extraction increased the measurable NRA in some species. Applications of nitrate reductase assay techniques to field work will be discussed.
A Cytokinin Complex in the Developing Fruits of Lupinus albus
Authors: DAVEY J. E. , VAN STADEN J.
Published: April 2006

The apices of Lupinus albus L. were analysed for cytokinin activity at three stages of development. Little cytokinin activity could be detected in the apices at the time of flowering. However, a considerable amount of activity was detected as the fruits developed. Separate analyses of seed and pod material indicated that there was a high level of cytokinin in both these parts of the fruit. After fractionation of the peaks of activity obtained from paper chromatograms on Sephadex LH‐20, four peaks of cytokinin activity were recorded. Two of these co‐eluted with zeatin and zeatin riboside. A third peak at an elution volume of 360–440 ml could be hydrolysed with β‐glucosidase to give activity at elution volumes corresponding to those of zeatin and zeatin riboside. This strongly suggested that both glucosylated zeatin and glucosylated zeatin riboside were present in the developing fruits of L. albus. The fourth peak at an elution volume of 160–280 ml did not disappear upon hydrolysis with β‐glucosidase, and it is possible that it represented a nucleotide cytokinin.
Characteristics of Root‐to‐Shoot Transport of Cytokinin 6‐Benzylaminopurine in Intact Seedlings of Citrus aurantium
Authors: MOZES RITA , ALTMAN ARIE
Published: April 2006

Transport of the cytokinin 6‐benzylaminopurine‐8‐14C in the root and shoot of intact Citrus aurantium L. seedlings was studied by “replacing” the 0.5 cm root tip with the uptake solution. The cytokinin was transported basipetally in the root and was distributed in an acropetal direction in the stem and into the leaves. Kinetic analysis of the transport for periods of up to 96 h revealed a characteristic advancing front of the label along the axis of the seedling. The estimated velocity of transport of 6‐benzylamino‐purine‐8‐14C in various regions of the intact root was 2.6 to 5.1 mm/h.

The transport of 6‐benzylaminopurine was predominantly in the transpiration stream, in stelar tissues of the root. Conditions of high transpiration favored enhanced transport to the shoot and an overall greater accumulation of the label. The total accumulation of 6‐benzylaminopurine in roots of intact seedlings after 48 h of transport was 354% of that in roots of shoot‐less seedlings. Root girdling and treatment of the root with KCN did not reduce the basipetal transport of the label in the root and into the shoot.

Radiochromalogram scanning of root extracts and analysis of the ethanol insoluble‐NaOH soluble fraction revealed considerable metabolic changes in the translocated cytokinin. Only 51% of the radioactivity remained in the original 6‐benzylaminopurine peak after 24 h of incubation. Two other, unidentified, metabolites were detected.

It is suggested that all the factors that affect the ascent of sap are involved in the long‐distance transport of cytokinins, and that the rate and mode of transport of cytokinins from the root system to the shoot may be a major factor in the expression of their physiological activity.
Comparative Basipetal Transport of 6‐Benzylaminopurine‐8‐14C, Gibberellin A3‐3H, IAA‐2‐14C, and Sucrose‐14C in the Root of Intact Citrus aurantium Seedlings
Authors: ALTMAN ARIE , MOZES RITA
Published: April 2006

The transport and distribution of IAA‐2‐14C, gibberellin A3‐3H, 6‐benzylaminopurine‐8‐14C and sucrose‐14C (U) were studied in whole seedlings of Citrus aurantium L. after “replacing” the root tip with the solution of radiochemicals. All four substances were transported basipetally in the root and were distributed to the stem and leaves. The pattern of distribution of the label from 6‐benzylaminopurine was similar to that of sucrose, while a considerably larger amount of gibberellin A3 was transported to basal regions of the root, away from the tip, and into the shoot. Contrary to these three substances, the basipetal transport of IAA in the root was very low, and the majority of the label was retained in the terminal sections of the root.

It is suggested that the different efficiencies at which various hormones move in the transpiration stream in the root may be an important factor in the attainment of a certain balance of hormones in the shoot.
Longitudinal and Transversal Microgradient of Acid Phosphomonoestherase in Growing and Geostimulated Maize Roots
Authors: MAYOR GUY , PILET PAUL‐EMILE
Published: April 2006

A relatively simple and reproducible technique to analyse both longitudinal and transversal biochemical microgradients in roots has been presented. Although no statistically significant differences of acid phosphomonoestherase activity were found between upper and lower faces of geostimulated maize roots, an increase of activity was demonstrated in the two first mm of the horizontal roots in comparison with the vertical roots. These results were discussed in conection with the growth variation of these roots.
Some Environmental and Nutritional Factors Affecting Growth and Sporulation of Aspergillus sydowi
Authors: OLUTIOLA P. O. , COLE O. O.
Published: April 2006

Aspergillus sydowi (Bain. & Start.) Thom & Church grew and sporulated best at 30°C. The best pH for growth and sporulation was 5.5. Light was stimulatory to sporulation but inhibitory to growth. Among the carbon sources employed, sucrose supported the best growth and sporulation. Nitrate, ammonium and asparagine were good nitrogen sources for growth and sporulation. During utilization of sucrose, the carbohydrates found in the mycelium included dulcitol, inositol, mannitol, arabinose, trehalose and galactose.
Cellulolytic Enzyme System in Culture Filtrates of Aspergillus sydowi
Authors: OLUTIOLA P. O. , COLE O. O.
Published: April 2006

During growth in liquid culture medium, that contained single soluble or insoluble cellulosic carbon source, Aspergillus sydowi (Bain. & Start.) Thom & Church released cellulolytic enzymes into the medium. The enzymes were separated by gel filtration followed by ion exchange chromatography into three components, all of high molecular weight. One of the components (Ac) has the character of a C1 cellulase enzyme. In the assay for hydrolysis of insoluble cellulose, the combined fractions, especially whenever the fraction under test contained the component Ac, released more glucose than when each component was employed alone.
Lipid Labeling in Normal and Nitrogen‐Deficient Squash (Cucurbita maxima) Leaves
Authors: DALGARN D. , HUBER D. , NEWMAN D. W.
Published: April 2006

Squash (Cucurbita maxima Duchesne) plants were grown on normal and on nitrogen‐deficient nutrients. The degrees of label incorporation into chloroplast lipids as well as non‐chloroplast lipids were determined. Nitrogen‐deficient tissues contain less chlorophyll, have a decreased chlorophyll a/b ratio, incorporate more label into phosphatidyl choline and phosphatidyl ethanolamine than into the chloroplast lipids such as mono‐ and digalactosyl diglycerides, have a reduced capacity to incorporate the hexose moieties into the glycolipids but normal capacity to incorporate bases into the phospholipids of non‐chloroplast constituents, and have a normal level of total fatty acids even though the level of linolenate is decreased. All of this would suggest that the most evident changes in membrane lipid constituents during nitrogen‐deficiency occur as changes in the chloroplast lipid constituents as opposed to the non‐chloroplast lipid constituents.
Morphogenetic Effects of Indole‐3‐acetic Acid and Benz(a)anthracene on Tobacco Callus
Authors: KOCHHAR T. S. , SABHARWAL P. S.
Published: April 2006

Callus obtained from haploid plants of Nicotiana tabacum was inoculated on media containing indole‐3‐acetic acid (IAA) and benz(a)anthracene (BaA) in various combinations. No cytokinin was included in the medium. Vegetative buds and roots differentiated on this callus. Higher concentrations of BaA favored vegetative bud initiation while higher IAA concentrations promoted root formation. However, these treatments proved ineffective on the callus derived from diploid tobacco plants.
Multiplication cellulaire et production lipidique en culture in vitro chez Taphrina insititiae et Taphrina pruni, parasites de Prunus domestica
Authors: SANCHOLLE MICHEL , SCHNEIDER ALAIN
Published: April 2006

Cellular Multiplication and Lipid Synthesis during in vitro Culture of Taphrina insititiae and Taphrina pruni, Parasites of Prunus domestica.

Two Taphrina species were grown on “yeast extract/glucose” and harvested at regular intervals. Their growth was estimated by dry mycelial weight and cell nitrogen. Lipids were recovered and measured by weighing. Phospholipids, which form the major portion of polar lipids, were measured by phosphorus assay.

Lipidic and nitrogenous products were studied with regard to the evolution of the cultures during the phase of active growth. The cells accumulated fats, but during the phase of autolysis, fat content decreased. Production of nitrogenous components was maximal during the autolytic phase. Phospholipids varied as nitrogenous and inversely to neutral lipids. There was apparently an antagonism between nitrogen assimilation and synthesis of neutral lipids. Different functions of neutral and polar lipids may be involved, so that the former act as a reserve material and the latter represent an essential structural cell constituent.

Fatty acids were analysed by gas liquid chromatography at various culture periods. Fatty acids from polar as well as those from neutral lipids exhibited great variations with regard to culture evolution. The ratio insaturated/saturated fatty acids is greater in polar lipids than in neutral lipids. These variations are discussed with regard to their consequences for the function of cell membranes.
A Simplified Medium for the Growth of Maize (Zea mays) Endosperm Tissue in Suspension Culture
Authors: SHANNON J. C. , LIU J.‐W.
Published: April 2006

In vitro cultures of maize (Zea mays L.) endosperm derived from the dent inbred A636 have been maintained in liquid culture using Straus' medium for over six years. We have studied the growth of this tissue in four basic media and various modifications of the organic constituents of these media. Auxins and kinetin did not improve growth rate or degree of cell dispersion and thiamine (0.4 mg/l) was the only vitamin required by this tissue. Growth equal to that in the standard Straus medium and improved cell separation was obtained in a medium containing only inorganic salts, sucrose, and thiamine. Although asparagine was not required when high quantities of NH4NO3 and KNO3 were included, more rapid growth was obtained when 2 g/l of asparagine was added. The simplified medium reported in this paper should facilitate the use of maize endosperm tissue in various studies of metabolism, hormone biosynthesis, etc.
Differences in Velocity of Auxin Movement Obtained by Intercept and Peak Arrival Methods
Authors: KRUL WILLIAM R.
Published: April 2006

Velocity of IAA movement was determined by noting the time of arrival of an ether‐soluble auxin wave, at a fixed distance, after presentation of an auxin pulse to bean (Phaseolus vulgaris L. cv. Pinto) hypocotyl segments. The effects of IAA adsorption on wave symmetry were reduced by monitoring the arrival of ether‐soluble auxin molecules. Velocity of auxin movement, as estimated by wave arrival, was slower than velocity estimated by the intercept method in controls and in both iodoacetate (IOAA) and 2,3,5‐triiodobenzoic acid (TIBA) treated tissue. Velocity of wave migration was reduced by both treatments but intercept velocity was reduced only by TIBA treatment. Velocity of IAA migration was faster in segments (independent of method of measurement) than from segments into agar by a factor of 4 to 8. The rate limiting step of auxin migration in the traditional agar‐plant sandwich is the partitioning of IAA between the tissue and agar. It was suggested that arrival curves for pulsed auxin migration are analogous to elution profiles of chromatographic columns and that at least two populations of mobile molecules with different velocities exist. It was also suggested that the two velocities represent migration of auxin on two different pathways: the faster velocity representing auxin movement of water films which coast highly crosslinked polymers in the segment and the slower component representing a population which moves primarily within the matrices of crosslinked polymers. Velocity of both populations may be a function of tissue hydration and charge interactions of mobile molecules and matrix polymers.
The effect of Sea Water and Temperature on the Germination Behaviour of Crithmum maritimum
Authors: OKUSANYA O. T.
Published: April 2006

The seeds of Crithmmm maritimum L. were germinated floating on various concentrations of sea water up to 50% at constant temperatures of 5, 10, 15, 20, and 25°C and at alternating temperatures of 5 and 15°C. 5 and 25°C. and 15 and 25°C. Significantly higher germination was obtained at alternating than at constant temperature. When two constant temperatures at which no germination occurred were alternated, good germination was obtained. There was reduced germination and increase in time of first germination as sea water concentration increased, in the absence of sea water, high temperature caused not only severe inhibition of germination but also permanent injury to the seeds. The results help to explain the germination behaviour of the species in nature.
Cadmium Accumulation by the Marine Red Alga Porphyra umbilicalis
Authors: McLEAN MAITLAND W. , WILLIAMSON PRANK B.
Published: April 2006

The characteristics of cadmium accumulation by the marine red alga Porphyra umbilicalis L. in culture are reported. The time course of uptake under various light conditions shows that cadmium is concentrated as the result of an on‐going anabolic process and not as a consequence of a pH gradient as provided by photo‐synthesis. The effect of cycloheximide is in agreement with de novo protein‐synthesis being a prerequisite For cadmium accumulation. Autoradiography suggests a specific intracellular location for bound cadmium—apparently the nucleus.
Effect of Cullural Conditions on the Growth of Agrostemma githago Cells in Suspension Culture and the Concomitant Production of an Anti‐Plant Virus Substance
Authors: TAKAYAMA SHINSAKU , MISAWA MASANARU , KO KEIDO , MISATO TOMOMASA
Published: April 2006

An extract of cultured Agroxieinma githago L. cells was found to show potent inhibitory activity against plans virus infection. The effects of cultural conditions on the growth of the cell suspension and on the production of the inhibitor were examined. Since the production of substance was dependent on growth. experiments were made to improve growth. The optimum temperature was 26 to 30°C and optimum pH of the medium before autoclaving was between 5 and 7. In a medium of higher osmotic pressure, the water content of the cultured cells was lowered markedly. The growth rate in a small volume of the medium was higher than that in a larger volume at an early stage of the cultivation, but it was not changed by different inoculum sizes.

The cells required thiamine and 2,4‐D for growth but no other vitamins or growth regulators. The optimum level of 2,4‐D was 0.1 mg/l.

Higher sucrose concentration in the medium gave higher production of cell mass and of the inhibitor. However, 3% of sucrose was selected as the most economical concentration. For normal cell growth, the presence of both NH4NO3 and KNO3 as nitrogen sources was required. The use of a single nitrogen source caused a long lag period or inhibition of the cell growth. KH2PO4 stimulated the growth when in was used in the level of 2.5 to 5 mM.

The cell adhesion on the surface of the fermentor sometimes causes trouble in a large‐scale cultivation. It was found that reducing the Ca2+ level in the medium prevented the cell adhesion and foaming remarkably.

Based on the results obtained, a modified medium was established which was excellent for shortening the culture period and for efficient production of the anti‐plant virus inhibitor.
Boron Uptake by Excised Barley Roots
Authors: BOWEN JOHN E. , NISSEN PER
Published: April 2006

Active uptake of boron (B) by excised barley roots is linear with time for at least 1.5 h. Although no evidence was found for accumulation of B against a concentration gradient. this component of B uptake does satisfy other criteria for an active transport process. Transport is inhibited by 0.05 mM 2,4‐dinitrophenol, 0.05 mM azide, 5 mM arsenate and 5 mM dicoumarol. Also, uptake is temperature‐sensitive, being nil at 2°C and maximal at 34 to 38°C. Boron uptake by barley roots increases with time when they are washed in aerated 0.5 mM CaSO4 solution.

A double reciprocal plot of the B uptake data manifests a series of phases separated by sharp transitions or “jumps”, and is compatible with the concept of multiphasic uptake mechanisms. Kinetic constants and transition points for the various phases were calculated accordingly. The fit of these data was compared statistically to three other relevant models, viz, the dual model, the “single + diffusion” model (a Michaelis–Menten term and a diffusion term), and the negative cooperativity model. In each case, the data were better represented by the multiphasic model.
Carbon Isotope Ratios (13C/12C) in Fractions of Field‐Grown Grape
Authors: DI MARCO G. , GREGO S. , TRICOLI D. , TURI B.
Published: April 2006

The carbon isotope ratio (δ13C%) in leaves and berries of Vitis vinifera L. was determined during the fruiting season.

The δ13C was from −24.6 to −26.3 in total leaf tissue, while it is from −22.7 to −24.3 in the aqueous extract of leaves. The δ13C in the berries was more stable, around −24, with no change during ripening. Malic and tartaric acid, isolated from the berries at the onset of ripening, showed a δ13C of −23.5 and −23.0 respectively. It was concluded that malic acid accumulated in the berries at the onset of ripening is not formed directly through β‐carboxylation.
Changes in Auxin and Cytokinin Activity in Roots of Red Oak, Quercus rubra, Seedlings during Lateral Root Formation
Authors: CARLSON WILLIAM C. , LARSON M. M.
Published: April 2006

Quercus rubra L. seedlings were partially root pruned to induce formation of new laterals. Auxins in root extract fractions that cochromatographed with IAA, and cytokinins in root xylem sap fractions that cochromatographed with zeatin and zeatin riboside, were quantified by bioassays at 24 h intervals after pruning. Auxin activity sharply increased in the first 24 h and then decreased to prepruning levels. Cytokinin activity also increased during the first 24 h. New laterals appeared 4 to 5 days after pruning. The possible sources and role of these two hormones in root initiation are discussed.
Tissue Culture of Maize
Authors: SHERIDAN WILLIAM F.
Published: April 2006

Callus of 12 strains of maize (Zea mays L.) was grown on a basal medium and on media supplemented singly with 0.3, 1.0 or 3.0 mM of either the glutamate, aspartate, or aromatic families of amino acids. Groth rate on basal medium difrered significantly among strains with Black Mexican Sweet corn growing most rapidly. Although there were three cases of simulation of callus growth at the 0.3 mM level and one case at the 1.0 mM level, generally the addition of amino acid families had either no effect or were inhibitory to growth rate. The sensitivity of inhibition varied among the strains tested at the 3.0 mM level except for the strain Ibadan B. Strains of the sweet, flint, pop and dent types of maize were all represented among the more fapidly growing strains and among those significantly inhibited by inclusion of amino acids in the cultural media. It remains to be determined as to whether the differences in growth response of the callus from the different strains is strain specific since, in all cases but one, callus was obtained from a single seedling of each strain.
Relations polyphénols — croissance: Mise en évidence d'un effet inhibiteur des composés phénoliques sur le transport polarisé de l'auxine
Authors: MARIGO GÉRARD , BOUDET ALAIN M.
Published: April 2006

Polyphenols and Growth: Inhibition of Polar Auxin Transport by Phenolic Compounds.

The possible effects of polyphenols on auxin transport in tomato plants (Lycopersicum esculentum Mill.) were investigated. For this purpose, the phenolic content of the material was stimulated by exogenously supplied quinic acid. After the apical bud had been excised, labelled compounds were applied to the cut surface, and the radioactivity transported to the roots was measured. Quinic acid treatment significantly delayed polar transport of labelled auxins (IAA or NAA). It did not affect the migration rate of sucrose−14C and leucine−3H. A number of evidences seems to demonstrate that the phenolics are responsible for these modifications, since similar results were recorded when the labelled compounds were supplied simultaneously with polyphenols from tomato. Moreover, a decreased polarity of NAA transport could be observed when the plants were submitted to treatments which lead to an increased level of phenols (boron deficiency, infection by Fusarium oxysporum). The data presented in this paper suggest that phenolic compounds could act on growth processes via the regulation of polar auxin transport.
Induced Protein Synthesis during the Adaptation to H2 Production in Chlamydomonas moewusii
Authors: KLEIN UWE , BETZ AUGUSTIN
Published: April 2006

Gas production by Chlamydomonas moewusii in the light has been followed by manometric techniques during the adaptation to anaerobiosis. The only detectable gases produced are CO2 and H2 CO2 is produced at a rather constant rate whereas H2 evolution increase with time. This increase of H2 evolution during the adaptation period can be inhibited by cycloheximide and by chloral hydrate, two inhibitors of protein synthesis. If the inhibitors are added to already adapted cells there is no effect on H2 evolution. Adapted cell suspensions are sensitive to oxygen. Incubation under O2 for 10 min inhibits the H2 evolution to 100%. After removal of oxygen the capability to evolve H2 can be restored only by a new adaptation period. This second adaptation to H2 evolution can also be inhibited by cycloheximide.
Indoleacetic Acid Oxidase Activity in Two High‐Peroxidase Tomato Mutants
Authors: PALMIERI S. , ODOARDI MIRIAM , SORESSI G. P. , SALAMINI F.
Published: April 2006

Homogenates of tomato (Lycopersicon esculentum Mill.) tissues oxidize IAA at a rate proportional to their peroxidase activity. Moreover, isoproteins with peroxidase activity catalyze also the oxidation of IAA. Two monogenic recessive mutations, olivacea and monstrosa, are involved in the control of the peroxidase‐IAA oxidase activity. In olivacea leaflets this activity is 15 times that of the normal; all the aerial organs of monstrosa show high activities, particularly the midrib. These high activities depend on the enhancement of the organ‐specific isoenzymes and on the derepression of the root isoenzyme band C2. This latter peroxidase‐IAA oxidase band is present in olivacea and monstrosa leaflets, in monstrosa stems and, less intensely stained, in monstrosa midribs. The reduction in length and weight of mutant organs and their epinastic and geotropic‐like behavior are associated with high peroxidase‐IAA oxidase activities and with the derepression of the root‐specific band C2. These results suggest an important role of the peroxidase‐IAA oxidase system in controlling the metric relationships among different organs of the plant. Olivacea and monstrosa are to be viewed as auxin‐related mutations controlling the synthesis of a group of proteins related in function.
Lipids from Bean, Barley and Sugar Beet in Relation to Salt Resistance
Authors: STUIVER C. E. E. , KUIPER P. J. C. , MARSCHNER H.
Published: April 2006

A comparison was made between the lipid and fatty acid composition of the salt‐sensitive bean (Phaseolus vulgaris L. cv. Saxa), the less salt‐sensitive barley (Hordeum vulgaris L. cv. Wisa) and the salt‐tolerant sugar beet (Beta vulgaris L. cv. Kawemono). Sugar beet roots showed a higher content of sterol components and sulfolipid as compared with bean and barley roots. The lipids of sugar beet roots contained more linoleic acid and less linolenic acid than those of bean and barley roots. For barley and sugar beet roots a higher amount of extra‐long chain fatty acids was observed than for bean roots. It was concluded that differences in membrane structure are correlated with differences in membrane permeability to sodium and chloride and in salt‐resistance of the studied species.
Leaf Response to Water Deficits in Soybeans
Authors: SIVAKUMAR M. V. K. , SHAW R. H.
Published: April 2006

Soybeans [Glycine max (L.) Merrill cv. Wayne] plants were subjected to an extended drying cycle in the field to investigate the leaf sensitivity to water deficits. Soybeans in irrigated plots were superior to those in non‐irrigated plots in the average size and number of leaflets per plant. Apparent differences in the leaf area distributions in the canopy seemed to be mediated by moisture stress effects associated with leaf senescence and light penetration in the lower depths of the canopy. A major decrease in leaf enlargement occurred near a leaf‐water potential of ‐8 bars, and at ‐ 12 bars, the growth was completely halted. Similar decreases were observed at a stomatal conductance of 0.4 cm/s and at 0.2 cm/s no enlargement was observed.
A Relationship between Length of Basis and Adventitious Root Formation in Pea Cuttings
Authors: VEIERSKOV BJARKE
Published: April 2006

A positive correlation between the length of the basis and the ability of the cuttings to form adventitious roots was observed in pea cuttings. Plants with a different basis length (the third internode) were obtained in different ways: Regulation by the level of irradiance, dark treatment or gibberellic acid. The length of the basis was also regulated by excision of the cuttings at different places on the stock plants. With increasing basis length an increase was found in the number of roots subsequently formed. The results were similar in cuttings from plants grown at different levels of irradiance or from dark treated plants. Optimal rooting was obtained by cutting the plants just above the second scale leaf. Cuttings from plants treated with 10−3M GA3 showed the same correlation between the length of the third internode and root formation as found in the other experiments, but the number of roots were at a lower level.
The Effect of Source—Sink Manipulations on Nitrogen Fixation in Peas
Authors: BETHLENFALVAY GABOR J. , ABU‐SHAKRA SALAH S. , FISHBECK KATHLEEN , PHILLIPS DONALD A.
Published: April 2006

The effect on nitrogen fixation of excising leaves or pods in pea (Pisum sativum L. cv. Alaska) was determined over a 60‐day period. Flower buds or their subtending leaves were removed, and C2H2 reduction, H2 evolution and N accumulation were measured at weekly intervals. Highest percentage nitrogen content in all treatments coincided with time of maximal C2H2‐reduction rates. Nitrogen fixation, calculated from C2H2 reduction and H2‐ evolution data, was significantly lower in the partially defoliated and generally higher in the depodded plants than in the controls. Total N accumulation was greatest in the depodded plants and least in the defoliated ones. Percentage nitrogen content and N2‐fixation rates in the depodded plants were maximized approximately 10 days later than in the defoliated or control plants. The absolute rates of C2H2 reduction and H2 evolution were significantly altered by plant organ removal, but the relative rates were proportional. As a result the ratios of H2/C2H4 production and the related relative efficiency of N2 fixation in the treatments were not significantly different from the controls.
Sensitivity of Cultured Tissue of Arabidopsis thaliana Races to Sulfanilamide
Authors: SCHOLL R. L. , DENNISON K. M.
Published: April 2006

Callus of Arabidopsis thaliana (L.) Heynh. was examined for the kinetics of sulfanilamide inhibition of growth. Two geographic races of this species were compared for relative sulfanilamide sensitivity (as assessed by dry weight increase on drug‐containing medium) and rate of drug uptake.

It was found that low concentrations of sulfanilamide in the culture medium (∼ 100 μM) inhibited callus growth and that low concentrations of p‐aminobenzoate (20 μM) competitively antagonized the sulfanilamide effect.

Racial variation for sulfanilamide sensitivity was demonstrated. A partially drug‐resistant race had greater sulfanilamide uptake (per gram fresh weight) than a sensitive race. suggesting that relative drug‐sensitivity was not determined by the capacity to exclude sulfanilamide.