bluuebunny/crossref_metadata_2025 huggingface dataset:
Enzymes of Heavy‐Metal‐Resistant and Non‐Resistant Populations of Silene cucubalus and Their Interaction with Some Heavy Metals in vitro and in vivo
Authors: MATHYS WERNER
Published: April 2006

The in vitro and in vivo effects of copper, zinc, cadmium, nickel, cobalt, and manganese on nitrate reductase, malate dehydro‐genase, isocitrate dehydrogenase, and glucose‐6‐phosphate dehydrogenase of zinc‐, copper‐ and non‐resistant populations of Silene cucubalus were investigated. During the in vitro experiments no resistant enzyme could be detected; enzymes of resistant and non‐resistant ecotypes had a similar sensibility to all the metals. Nitrate reductase was the most sensitive enzyme. During the in vivo experiments remarkable differences were found. The nitrate reductase and the isocitrate dehydrogenase of the zinc‐resistant population were activated when adding zinc to the culture medium, especially the nitrate reductase showed high activities at zinc concentrations where the nitrate reductase of the non‐zinc‐resistant populations was nearly completely inhibited. The zinc‐resistant ecotype had a real need for zinc.
Peroxidases as Indicators of Growth and Differentiation in Aspen Callus Cultures
Authors: WOLTER KARL E. , GORDON JOHN C.
Published: April 2006

Aspen (Populus tremuloides Michx.) callus tissue grown on a synthetic medium containing either an auxin (2,4‐dichloro‐phenoxyacetic acid) or cytokinin [6‐(3‐methyl‐2‐butenylamino) purine] differed in growth rate, total peroxidase activity, peroxidase isoenzyme expression, and in lignin, cell wall sugars and extractive content. Tissue treated with auxin increased more rapidly in fresh weight, but stopped growing sooner than did the cytokinin‐treated tissues. Lignification also proceeded more rapidly, and lignin formed a greater fraction of the cell wall weight in auxin‐treated tissue. For both treatments, peroxidase activity and growth rate were positively related (r = 0.96). Polyacrylamide gel electrophoresis showed some quantitative, but few qualitative, isoenzyme differences with hormonal treatment and growth rate.
Effects of Ionic Strength of Nutrient Solutions on Phosphate Uptake by Sunflower
Authors: PETTERSSON SUNE
Published: April 2006

Active phosphate uptake by the roots of young sunflower plants was stimulated nonspecifically by increasing the total salt concentration of the uptake solution. Inhibition of active uptake by DNP‐treatment removed the salt stimulation. Independently of the rate of active uptake the amount of phosphate present in the free space of the roots increased as the salt concentration was raised. It is suggested that at low ionic strength of the nutrient solution the initial passive step of ion transport through the root free space can limit the overall uptake rate.
Activité néformatrice d'acides ribonucléiques extraits de tumeurs végétales
Authors: ROUSSAUX JACQUELINE
Published: April 2006

RNAs extracted from crown‐gall tumors, induced by Agrobacterium tumefaciens (strain B6) on stems of Datura stramonium L., have been isolated by the phenol method and purified through Biogel P 60 columns. These RNAs have been transformed into complexes with l‐amino acids by incubation in a medium containing: Tris HCI buffer, pH 7.6, ATP, MgCl2, a mixture of l‐amino acids and a polypeptide synthetase purified from Alcaligenes faecalis. The inoculation of stems of Datura plants with these complexes induces the development of nodular outgrowths, whereas other complexes made from RNAs isolated from healthy Datura plants, from Agrobacterium tumefaciens, Escherichia coli and Alcaligenes faecalis do not cause any hyperplasia under our experimental conditions. The analysis of the results obtained, supported by histological studies of the outgrowths, suggests that these neoformations should be of tumoral nature.
Light Rquirements for Photoperiodic Sensitivity in Cotyledons of Dark‐grown Pharbitis nil
Authors: FRIEND D. J. C.
Published: April 2006

The light requirements for induction of flowering by a long dark period were investigated in dark‐grown seedlings of Pharbitis nil Chois, cv. Violet. The cotyledons bcame photoperiodically sensitive to a 24 h dark period by two 1 min red irradiations (6.3 μmol m−2 S−1) separated by a 24 h dark period. The reversibility of the effect of brief red irradiations, and the effectiveness of low energies of red irradiation suggest the involvement of phytochrome in the induction of photoperiodic sensitivity. Partial de‐etiolation occurred after these brief periods of red irradiation but the seedlings were not capable of net CO2 uptakeeven 7 h after the start of the main light period that followed the critical dark period. A changing response to the duration of the priod of darkness given between the two short red irradiations showed the the correct phasing of an endogenous photoperiodic rhythm is needed for the attainment of photoperiodic snsitivity.
The Effects of Age and Root Formation on the Life‐Span of Excised Cotyledons of Cucurbita pepo
Authors: MOHAMMAD A. M. S. , AL‐MASHHADANI Y.
Published: April 2006

Root initiation in Cucurbita cotyledons excised at various ages was studied in nutrient solution and water. The time required for root initiation depends on the age of the cotyledon and on the rooting medium. Nutrient solution favoured root formation. Maximum number of roots, maximal total root length, and maximum life‐span were found with cotyledons excised at an age of 14 days. Excision earlier or later resulted in less roots, less total root length, and shorter life‐span.
Respiration Rate and Mitochondrial Activity in Iris Bulbs
Authors: KOLLÖFFEL C. , VAN LOON‐LIEVE M. P.
Published: April 2006

The oxygen uptake of iris bulbs (Iris×hollandica‘Wedgwood’) which had been stored dry at 30 C (“retarded’ bulbs) was low (10 μmol O2 per h and bulb), the oxygen uptake of the intact bulb, the three outer fleshy scales and the remaining central part of the bulb increased three‐ to fourfold, nearly twofold and fourfold, respectively.

Mitochondria were isolated from the scales of retarded and activated bulbs and their oxygen consumption with succinate, l‐malate (plus pyruvate). x‐ketoglutarate and NADH as substrate was measured polarographically. The oxidative capacity of mitochondria isolated from the scales of activated bulbs was only slightly higher than that from retarded bulbs when calculated on a tissue basis. No difference was found between the phosphorylation efficiency, respiratory control, cytochrome c deficiency, succinate dehydrogenase, malate dehydrogenase, succinate‐cytochrome c rductase, NADH‐cytochrome c reductase and cytochrome oxidase activity of the retarded and activated bulbs.

The increase in the in vitro oxygen uptake of the scales after transition from 30 to 13 C was not accompanied by an equal increase in the oxidative capacity of their mitochondria suggesting that they are not responsible for this rise in oxygen uptake.
Effect of Abscisic Acid at Different Levels of Soil Water Potential on the Transpiration of Zea mays
Authors: TALHA MAHMOUD , LARSEN POUL
Published: April 2006

The effect of different levels of both exogenous abscisic acid (ABA) and soil water potential on transpiration from intact maize leaves was studied in growth chamber experiments. The transpiration rate showed a more consistent decrease with decreasing soil water potential than with increasing concentration of applied ABA. The effect of exogenous ABA on the transpiration rate was markedly lower at low than at high levels of soil water potential.
Manipulation of IAA‐Oxidase Activity and Auxin‐Deficiency Symptoms in Intact Cotton Plants with Manganese Nutrition
Authors: MORGAN PAGE W. , TAYLOR DANIEL M. , JOHAM HOWARD E.
Published: April 2006

Cotton (Gossypium hirsutum L. cv. Deltapine 15) seedlings were grown in solution culture in which the Mn2+ level was varied. Following an initial period, a series of shifts in manganese nutrition were employed, each lasting 14 days. Appearance was observed and fresh weight, IAA oxidase (IAAO), peroxidase and IAAO inhibitor levels were determined. After the initial 3 weeks of treatment, growth was negatively correlated with IAAO (or peroxidase) activity. All shifts in manganese nutrition resulted in predicted changes in IAAO activity, growth and plant appearance during a second 2‐week period of the experiment. Continuously deficient plants exhibited highest leaf abscission and IAA oxidase activity, and lowest growth of all treatments. Plants shifted from deficient to control levels of Mn2+ exhibited a marked decline in IAAO activity, increase in growth and absence of leaf abscission. Plants shifted from borderline deficiency to deficient Mn2+ exhibited a major increase in IAAO activity, reduction in growth and extensive leaf abscission. Control and borderline toxicity plants maintained normal IAAO activity, growth, and appearance. During a final 2‐week period, symptom expression was intensified. In particular, the initial borderline deficiency plants shifted to deficient levels of Mn2+ abscised most of those leaves that expanded after the shift in treatment. In addition, shifts of some plants to toxic Mn2+ levels during the third phase of the experiment produced a complete cycle of manipulation. Plants initially deficient in Mn2+ with high IAAO and low growth recovered growth and declined in IAAO when shifted to control Mn2+ and then suffered severe inhibition of growth and toxicity symptoms when shifted to high Mn2+.

In all cases changes in enzyme activity, growth, leaf abscission and similar symptoms were most strongly expressed in the youngest tissue or that with the greatest potential for growth during the interval of a particular treatment. Since total growth, IAAO, leaf abscission, internode length and similar symptoms were consistently manipulated in both directions (increase or decrease in intensity or degree) by raising or lowering Mn2+ levels in the plant culture medium, we conclude that there is a causal relationship between IAAO and these responses that involves destruction of auxin.
Stimulation of Growth of Peppermint (Mentha piperita) by Phosfon, a Growth Retardant
Authors: CALABRESE EDWARD J. , HOWE KENNETH J.
Published: April 2006

The shoot growth and fresh weight of Mentha piperita grown in soil were stimulated at concentrations of 1.26 × 10−5M to 7.77 × 10−4M phosfon (2,4‐dichlorobenzyl tributyl phosphonium chloride) while higher concentrations resulted in retardation of growth. Concentrations of 6.30 × 10−7M to 3.78 × 10−5M caused retardation of growth in mineral nutrient solution, and even death at the highest concentrations. However, when the M. piperita plants were grown in mineral nutrient solutions at concentrations of phosfon which had been sequentially lowered from 2.52 × 10−8M to 2.52 × 10−12M, the shoot growth and fresh weight were stimulated as in the case of plants grown in phosfon treated soil.
A New Laboratory Method Used for Investigating the Uptake, Translocation and Metabolism of Bark Banded Morphactin by Trees
Authors: NEUMANN PETER M. , DOSS ROBERT P. , SACHS ROY M.
Published: April 2006

Cut twigs of Monterey pine(Pinus radiata D.Don) were banded with a 14C labelled morphactin formulation and the lower half of the twig placed in a Scholander type pressure bomb. Water was pumped through the twig from a reservoir inside the bomb and exudate collected from the protruding end of the twig. Using this method it was possible to determine that the slowest step in the translocation of morphactin was the passage across the outer layer of bark. Subsequent passage through the twig was not affected by girdling the bark suggesting that morphactin was translocated upwards via the xylem. The 14C compound in the exudate from live twigs differed from morphactin and was tentatively identified as the carboxylic acid derivative of the morphactin ester.

The cut twig system facilitated studies on the uptake, metabolism and translocation of morphactin and should prove useful for studying the uptake and fate of other chemicals considered for bark application to trees.
Effect of Gibberellic Acid, (2‐Chloroethyl) Phosphonic Acid, Actinomycin‐D and Cycloheximide on the Activity and Leaching of Some Hydrolases in Pollen Suspension Cultures of Crotalaria juncea
Authors: BHANDAL IQBAL SINGH , MALIK C. P.
Published: April 2006

Gibberellic acid (GA3) 20 mg 1−1 and (2‐chloroethyl) phosphonic acid (Ethephon) 10 mg 1−1 enhanced pollen tube length in Crotalaria juncea L. GA3 markedly increased the activity of amylase, acid phosphatase and β‐glucosidase and enhanced leaching of amylase and acid phosphatase enzymes. The rise in the activity level and leaching of amylase and acid phosphatase after Ethephon treatment was comparatively less than that of GA3 and the response to Ethephon was restricted to the 45 and 90 min period of culturing. Ethephon did not affect the activity/leaching of β‐glucosidase significantly. Actinomycin‐D (Act.D) 25 mg l−1 and Cycloheximide (CH) 10 mg 1−1 reduced the tube growth as well as activity of these enzymes suggesting their de novo synthesis during pollen tube growth.
The Threshold Stimulus for Geotropism
Authors: JOHNSSON ANDERS , PICKARD BARBARA G.
Published: April 2006

The minimum effective geotropic stimulation time is very short for coleoptiles, hypocotyls and roots. New data from the literature are used to emphasize that the minimum time is of the order of 10–20 s. The existence of such a short minimum time should be carefully considered in the design of geotropic experiments in Spacelab, which are now at the planning stage. Even brief acceleration periods at 1 g or less during a flight might cause unintentional geotropic effects.

The short minimum stimulation time also has relevance for the statolith theory: since the distance which an amyloplast can sediment during this time is very small, no long sedimentation distance is likely to be required for georeception. Moreover, the magnitude of thermal noise must be considered in evaluating proposals for the georeceptive mechanism.
Osmotic Adaptation in Panicum repens. Differences Between Organ, Cellular and Subcellular Levels
Authors: RAMATI A. , LIPHSCHITZ NILI , WAISEL Y.
Published: April 2006

The process of osmotic adaptation was studied in leaves of Panicum repens. Two phases were observed: the first phase, which continued for 2–4 days, was mainly characterized by dehydration of leaves, a fast synthesis of organic acids and penetration of sodium into leaf cells. Chloride becomes dominant in the leaves only from the third day of exposure and onwards. The second phase of adaptation lasted for 4–6 days. During this phase, a decrease in organic acid content and an increase in leaf‐chloride content was observed. In spite of the fact that the osmotic potential of the leaves reached lower values than that of the external medium already after 2 days, the rate of growth of the plants was hampered. Such inhibition of growth disappeared 6–8 days after exposure to salinity.

Ion content of the cell walls, chloroplasts and vacuoles of Panicum leaf cells was investigated during the various stages of osmotic adaptation. An increase in sodium and chloride content of the cell walls during the early period of adaptation probably prevented the full osmotic adaptation of the protoplasts. It is suggested that a locally unbalanced distribution of ions may be one of the reasons for the decrease in growth rate during the process of osmotic adaptation and frequently after that.
X‐ray Microanalysis of Phosphorus in Scenedesmus obtusiusculus
Authors: TILLBERG JAN ERIC , BARNARD TUDOR , ROWLEY JOHN
Published: April 2006

Results from energy dispersive x‐ray microanalysis indicate considerable variation in phosphorus as well as in other elements found in polyphosphate granules in cells of Scenedesmus obtusiusculus starved of phosphorus for 24, 36 and 48 h. Comparison is made with cells at a 3‐h stage of synchronization and after 48 h cultivation in a phosphorus‐containing medium. After 48 h with a very limited external source of phosphorus, phosphorus was not detectable in‘polyphosphate granules’ in Epon‐Araldite sections unless the resin and other organic molecules were removed by plasma microincineration. In spite of the low amounts of elements (Mg. Al, Si, P and Ca) detected in these granules they are still dense to electrons in unstained sections, like the granules in cells cultivated in the presence of phosphorus. That suggests that the localized differences in the structural packing of elements or radicals in the polyphosphale polymer is more important For visualization of unstained polyphosphate granules than the absolute concentration of phosphorus or other elements. In contrast to previous assumptions, the abundance of morphologically‐observable‘polyphosphate’ granules can no longer be taken as an index of mobilizable phosphate reserves.
Culture of Shoot Apices of Theobroma cacao
Authors: ORCHARD J. E. , COLLIN H. A. , HARDWICK K.
Published: April 2006

Surface sterilized buds of young cocoa plants (Theobroma cacao L.) taken at particular stages of the flush cycle were placed in Linsmaier and Skoog agar medium supplemented with a range of growth regulators. Only buds taken at the 1–2 (dormant) stage of the flush cycle and treated with gibberellic acid (GA3) alone and GA3plus kinetin (KN) supplement showed bud opening. In liquid Linsmaier and Skoog medium buds isolated at the 1–2 stage also responded to GA3 and KN. In this case addition of KN caused bud opening, while GA3 either initiated bud opening only or opening followed by leaf expansion depending on the concentration of GA3 supplied. Bud development was inhibited when ABA was included in the medium hut this was overcome by the presence of GA3 but not KN. Since a hormonal supplement was required for any response from the excised buds, it is suggested that the intermittent growth of the shoot apex in the intact plant may be determined by hormonal stimuli derived from other parts of the plant. The findings also indicate that the bud apices could be maintained in culture for long periods which may provide a basis for the development of a micropropagation procedure for cocoa.
Amylase and Invertase Activities and Carbohydrate Contents in Relation to Physiological Sink in Carnation
Authors: FAWZI A. F. A. , EL‐FOULY MOHAMED M.
Published: April 2006

In carnation, Dianthus caryophyllus L. cv. Hanacy, initiation of flower primordia was followed by mobilization of polysaccharides from leaves to developing flower buds and mature flowers. This process functioned by integrative activities of amylase and invertase, ensuring abundant flow of the mobilized carbohydrates from the source to the sink. Successive stages of floral development exhibited different sink strengths as indicated by amylase and invertase activities and carbohydrate contents in stem apices, which increased with progression of floral development.
Development in vitro of Nephrolepis exaltata cv. Bostoniensis Runner Tissues
Authors: LOESCHER WAYNE H. , ALBRECHT CAROLYN N.
Published: April 2006

Study of organogenesis in vitro in runner tissues of the fern Nephrolepis exaltata cv. Bostoniensis has shown that the process involves two stages: the first being primoirdium initiation and the second involving release of these primordia from an apparent quiescent state. In vitro shoot development from the primordia required light and an exogenous supply of carbohydrate. No exogenous growth regulators were necessary, but rate of shoot development was promoted by both NAA and kinetin. Root initiation occurred in both the light and dark and was promoted by 2,4‐D and NAA, but neither was essential. Organogenesis was generally inhibited with standard levels of Murashige and Skoog inorganic salts, but inhibition could be avoided with the use of dilute levels.
Effect of Light on Deamination and Oxidation of Adenylic Compounds in Cotyledons of Pharbitis nil
Authors: NGUYEN JACQUELINE
Published: April 2006

Since labelling of ureides from adenine‐8‐14C is higher in dark than in light, the influence of light on the deamination and the oxidation of adenylic compounds by cotyledon discs of Pharbitis nit was investigated. Among the three possible adenylic precursors for the deaminative step, adenine was found to be the best compound for the study of the deaminative rate, adenosine being easily hydrolyzed into adenine, and AMP undergoing an apparent complete hydrolysis before entering the cells. By analysis of adenine‐8‐14C metabolism for brief periods, it was determined that the rate of deamination of adenylic compounds was faster in light than in dark. In contrast, the activity of xanthine dehydrogenase was much higher in the dark than in light. The level of the activity of uricase was the same in both light and dark.
Tissue and Cell Culture of ‘Passe Crassane’ Pears: Amylase Pattern of Cultured Tissues Compared with Whole Fruit
Authors: PECH JEAN‐CLAUDE , LATCHÉ ALAIN , FALLOT JEAN
Published: April 2006

Calluses and cell suspension cultures were initiated from young and fully developed fruits and from stem and petiole tissues of ‘Passe Crassane’ pears. On a dry weight basis, proliferation is significantly higher in tissues from full‐grown fruits and petioles. Cullus tissues grown in vitro have a protein content up to 25 times higher than the initial quiescent organ. Three amylase fractions (2 β amylases E, and E2: 1 α amylase E3) were isolated by gel filtration on Sephadcx G‐100 and isoenzymes revealed in these fractions after polyacrylamide gel electrophoresis.

Comparison of amylase activity in actively growing cells and in auxin‐starved cell suspensions shows that β‐amylase activity is mainly a function of cell growth, while α‐amylase activity is more related to the age of the cells.

The presence of two isoenzymes in the β‐amylase E2 fraction was found to be highly characteristic of young fruits. The same polymorphism was found in all the strain of tissues thus indicating that tissues grown in vitro retain or revert to a juvenile biochemistry. The growth hormone. 2,4‐dichlorophenoxyacetic acid, used to support cell division, is demonstrated to be responsible for the reversion of the β‐amylase polymorphism from a mature to a juvenile phenotype in mature fruit explants incubated in vitro.

The interest of fruit tissue and cell culture for the study of fruit physiology is questioned and discussed.
Environmental control of turion formation in curly pondweed (Potamogeton crispus)
Authors: SASTROUTOMO SOETIKNO S.
Published: April 2006

The turions of Potamogeton crispus L. develop in early summer and function in propagation and dispersal. Under natural conditions during longday periods, an average minimum air temperature of more than 12°C was found to be important for turion formation. Experiments with controlled environments indicate that both temperature and photoperiod regulate turion formation. Turions can be induced at 13°C or above but not at 8 or 10°C. At a temperature range of 13–24°C turions form in both 12‐ and 16‐h days, but not in 8‐h days. By increasing temperature from 24 to 30 or 35°C turions can be induced under 8‐h days. Light intensity was found to be important in the formation of turions.
Formation of aerenchyma in roots of Zea mays in aerated solutions, and its relation to nutrient supply
Authors: KONINGS HENDRIK , VERSCHUREN GER
Published: April 2006

The formation of lysigenous cavities (aerenchyma) in the root cortex of maize, Zea mays L. cv. Capella, under well‐aerated conditions has been studied in relation to the composition of the nutrient solutions. Nitrogen, either supplied as nitrate or as ammonium, reduced the cavity formation by the roots. This reduction was most apparent at nitrate concentrations above 2 mM. Cavities were increasingly formed when the nitrate concentration was decreased and they reached their largest dimensions in roots growing in water. Thus, inadequate availability of nitrogen leads, under acrated conditions, to deterioration of cortex cells and cavity formation in the maize roots. It is suggested that cavity formation in these roots is connected with reduced nitrogen assimilation.
Effect of morphactin on certain plant growth substances in bean roots
Authors: PARUPS E. V.
Published: April 2006

The effect of morphactin (methyl‐2‐chloro‐9‐hydroxyfluorene‐9‐carboxylate) on the content of several plant growth substances in bean roots was determined. Beans (Phaseolus vulgaris L. cv. Spartan) were soaked in aqueous solutions of morphactin, 1 x 10‐4, 1 x 10‐5, and 1 x 10‐6M and grown in moist vermiculite. As controls were used beans grown in water‐moistened vermiculite either intact or having the root tips removed (decapped). The roots, morphactin‐treated, controls, and the decapped ones were analyzed for indol‐3‐yl acetic acid (IAA), indol‐3‐yl acrylic acid (IAcA), indol‐3‐yl pyruvic acid (IPyA), indol‐3‐yl lactic acid (1LA), abscisic acid (ABA), gibberellins GA1, GA3, GA4, and GA9 using gas‐liquid chromatographic methods. Morphactin, while affecting the geotropical responses, changed also the growth substance content of roots. IAA, ABA, GA1, and GA9 contents decreased, IPyA, IAeA, GA3, and GA4 contents were not affected and ILA content increased slightly with increasing dosages of morphactin. Growth substance pattern of decapped roots resembled that of the roots treated with the highest dose, 1 x 10‐4M, of morphactin.
Phenylalanine ammonia‐lyase activity in callus cultures of Pinus elliotii
Authors: LAU YIU‐LAM , SCHELD HERBERT W. , COWLES JOE R.
Published: April 2006

Phenylalanine ammonia‐lyase (PAL) activity increased 8‐ to 12‐fold in pine (Pinus elliotii Engelm.) callus tissue within 2 days after subculturing on fresh medium. Factors such as increasing the sucrose content of the media, imposing additional tissue in jury or subculturing more frequently did not cause additional stimulation of PAL activity. The rapid increase in PAL activity appeared to be due to enzyme activation, since cycloheximide did not appreciably reduce the stimulation of PAL activity. The subsequent loss of increased PAL activity with age was reduced by cycloheximide and a cool growth environment.
Moss phosphofructokinase is less sensitive than other plant phosphofructokinases to inhibition by phosphoenolpyruvate
Authors: Kelly Grahame J. , Latzko Erwin
Published: April 2006

Phosphofructokinase was partially purified from the moss Brachythecium rutabulum (Hedw.) Bt. Eur. and found not to be inhibited by 400 μM phosphoenolpyruvate, whereas spinach and Chlorella phosphofructokinases were inhibited over 80% by phosphoenolpyruvate at one‐fifth of this, concentration. Mixing experiments indicated that the insensitivity of the moss phosphofructokinase was not an artifact of the extraction procedure. Other kinetic and regulatory properties of moss phosphofructokinase were similar to those reported for the enzyme from other plants.
Influence of temperature and water potential on root growth of white oak
Authors: Teskey Robert O. , Hinckley Thomas M.
Published: April 2006

Root growth of white oak (Quercus alba L.) was observed under field conditions using a rhizotron. The effects of temperature, soil water potential, and leaf water potential were evaluated on three measures of root growth and development: root elongation rate, number of growing roots, and root growth intensity (sum of projected root area compared to the total root viewing area). Root elongation rate was linearly related to changes in soil temperature and soil water potential. At soil temperatures less than 17deg;C, temperature was the dominant factor affecting rate of growth, bat at temperatures greater than 17°C soil water potential became the important factor. Unlike root elongation rate, the number of growing roots and root growth intensity increased at cold soil temperatures (8°C) and at soil water potentials of‐0.3 to ‐0.8 MPa. At high soil water potentials (‐0.1 MPa) root elongation rate reached a maximum while the number of growing roots and root growth intensity were low. These differences showed that root growth and development were not exclusively affected by the soil environment. In addition, the relationship between root growth and predawn leaf water potential suggested that root growth was a contributing factor to the drought resistance of white oak.
Changes in phenolic acids and abscisic acid in sugar pine seed coats during stratification
Authors: Murphy J. Brad , Noland Thomas L.
Published: April 2006

The phenolic acids and abscisic acid (ABA) of sugar pine (Pinus lambertiana Dougl.) seeds coats, separated by high‐pressure liquid chromatography, were analyzed during 90 days stratification of the seeds. Although levels of seed coat phenolic acids and ABA declined significantly during, stratification, this decrease did not appear to be responsible for the loss of dormancy due to stratification. Lack of improved germination following washing, cracking, or removal of the seed coats, plus additional evidence, did not support a significant role for the seed coat in the dormancy of sugar pine seeds.
Changes in phenolic acids and abscisic acid in sugar pine embryos and megagametophytes during stratification
Authors: Murphy J. Brad , Noland Thomas L.
Published: April 2006

The phenolic acids and abscisic acid (ABA) of sugar pine (Pinus lambertiana Dougl.) embryos and megagametophytes, separated by high‐pressure liquid chromatography, were analyzed during 90 days stratification of the seeds. The phenolic acids occurred mainly as glycosides. Following hydrolysis, the majority of phenolics present could be identified as common benzoic and ciranamic acid derivatives. Levels of phenolic acids were relatively low in dormant seeds, but increased substantially in the embryos during stratification at 5°C, particularly cinnamic acid, p‐coumaric acid, ferulic acid, and one unknown. This active synthesis during stratification did not support an inhibitory function for phenolic acids. During stratification at 5°C, changes in ABA levels in both tissues followed a triphasic pattern, with no loss during the first 30 days, a significant decrease the second 30 days, and a lesser decrease the last 30 days. Loss of ABA from moist seeds at 25°C occurred three times as rapidly, so that by 30 days the ABA level of these seeds was equivalent to that of seeds stratified 90 days at 5°C; however, dormancy was not alleviated at 25°C. Application of exogenous ABA (10−7 to 10−4M) to stratified seeds did not significantly reduce germination. Together, the above results did not support a primary role for ABA in the maintenance of dormancy in sugar pines.

A correlated increase in phenylpropanoid metabolism and respiratory capacity with increased germinability during stratification suggests that loss of dormancy may be more closely dependent on increased levels of growth promoters or shifts in metabolic pathways.
Differences in some morphological, physiological, and biochemical responses to drought stress in two contrasting populations of Populus przewalskii
Authors: Lei Yanbao , Yin Chunying , Li Chunyang
Published: April 2006

The cuttings of Populus przewalskii Maximowicz were exposed to three different watering regimes (100, 50, and 25% of the field capacity) in a greenhouse to characterize the morphological, physiological, and biochemical basis of drought tolerance in woody plants. Two contrasting populations of P. przewalskii were used in our study, which were from the wet and dry climate regions in western China, respectively. The results showed that there were significant differences in responses to three different watering regimes in both populations tested; drought not only significantly affected dry mass accumulation and partitioning but also significantly decreased chlorophyll pigment contents and accumulated free proline and total amino acids. On the other hand, drought also significantly increased the levels of abscisic acid, hydrogen peroxide, and superoxide radical as secondary messengers to induce the entire set of antioxidative systems including the increase of reduced ascorbic acid (ASA) content and the activities of superoxide dismutase, guaiacol peroxidase, ascorbate peroxidase, and glutathione reductase (GR). Moreover, there were different responses to drought stress between the two contrasting populations of P. przewalskii. Compared to the wet climate population, the dry climate population showed lower dry matter accumulation and partitioned more biomass to root systems, and accumulated more free proline and total amino acids for osmotic adjustment. The dry climate population also showed more efficient antioxidant systems with higher content of ASA and higher activities of ascorbate peroxidase and GR than the wet climate population.
Lateral root development, including responses to soil drying, of maize (Zea mays) and wheat (Triticum aestivum) seminal roots
Authors: Ito Kaori , Tanakamaru Koji , Morita Shigenori , Abe Jun , Inanaga Shinobu
Published: April 2006

The spatial distribution of lateral roots in the soil is an important factor influencing water and nutrient absorption. However, lateral root development has rarely been studied in detail, especially concerning morphological variations, mainly because such examinations are both time‐consuming and laborious. We measured the number and length of all first‐order lateral roots on the seminal roots of maize (Zea mays L.) and wheat (Triticum aestivum L.) to investigate variations in linear frequency and length. This was conducted with reference to species, root types, and positions on their parental roots. Although the linear frequency of first‐order lateral roots varied along the root axis in maize, the variation was not as great as in wheat. Variations were found in the length of lateral roots among plant species, root types, and positions on their parental root axes. Such variations in the length of lateral roots along the root axes were caused by differences in the elongation period of lateral roots rather than those in the elongation rate. Additionally, we examined the effects of soil drying on lateral root development. As a response to soil drying, the length of lateral roots varied depending on the period they were placed under the stressed condition. Moderate soil drying could also accelerate the elongation of some lateral roots. Variations in the length of first‐order lateral roots and their responses to soil drying could help distribute their tips thoroughly throughout the soil. This might be adaptive for water absorption for root system development when resources are limited.
Stresses applied for the re‐programming of plant microspores towards in vitro embryogenesis
Authors: Shariatpanahi Mehran E. , Bal Ugur , Heberle‐Bors Erwin , Touraev Alisher
Published: April 2006

Microspore embryogenesis is the most commonly used method to produce doubled haploids. It is based on the ability of a single haploid cell, the microspore, to de‐differentiate and regenerate into a whole plant after being exposed to stresses, such as low or high temperatures, carbon starvation and colchicine. Some stresses such as temperature treatments and carbon starvation have been used with success in many plant species, whereas others such as colchicine had limited application in a few species. Reports on the application of whole plant treatments with feminizing agents on inflorescences and buds are scarce. Furthermore, the technical means to apply some stresses such as γ‐irradiation are not readily available. Recently, novel stresses such as pH, inducer chemicals, carrageenan oligosaccharides and heavy metals were reported to induce microspore embryogenesis. It remains to be seen, however, whether these stresses are effective in a wider range of species. Finally, pretreatment of cultured cells with high concentrations of 2,4‐D efficiently induces somatic embryogenesis in several species (carrot, alfalfa). However, reports on the use of this particular chemical stress are not available in microspore embryogenesis. The paper presented here gives an overview of various stresses and mechanisms of action of these stresses in inducing microspore embryogenesis.
The Effects of Different Cotton Varieties on the Carmine Spider Mite, Tetranychus cinnabarinus Boisd. (Acari: Tetranychidae)
Authors: ŞEngonca Ç. , Lababidi M. S. , Gerlach S.
Published: April 2006

The aim of this study was to delta differences in resistance to the carmine spider mite, Tetranychus cinnabarinus between cotton varieties grown in different areas. The effects of 8 varieties from several countries cm the development, longevity and fecundity of T‐cinnabarinus were investigated in the laboratory. On leaves of the Egyptian cotton, Gossypium vitifolium, variety Giza 75, both females and males required a longer period to complete development than on the G. hirsutum varieties Coker 310 and MCH H. Female mites reared on the variety Coker 310 lived significantly longer and had the longest oviposition period. The largest total progeny per female was observed on the varieties Coker 310 and MCH H, the smallest on the varieties Aleppo 1 and Giza 75. The cotton varieties had no effect on the sex ratio of T. cinnabarinus. In general, the G. hirsutum varieties Coker 310 and MCH 11 appeared to be most supportive for T. cinnabarinus, whereas the G. vitifolium variety Giza 75 clearly showed reduced susceptibility.
Different Behavior of Brassica juncea and B. carinata as Sources of Phoma lingam Resistance in Experiments of Interspecific Transfer to B. napus
Authors: Dolores Sacristan Maria , Gerdemann Maria
Published: April 2006

With the aim to transfer Phoma lingam resistance into rape, successful interspecific crosses were made between three oilseed rape varieties (Brassica napus) and the resistant species B. carinata and B. carinata. Although both hybrid types B. napus×B. juncea and B. napus×B. carinata showed the same high level of resistance as the respective resistant parent, the resistance could be only transferred from juncea crosses. After three backcross generations, lines morphologically undistinguishable from rape, fertile, and with a high degree of resistance were obtained. The resistance of B. carinata was practically lost in the first backcross. A possible explanation of this different behavior could be a higher recombination between the genomes B and C (juncea crosses) than between B and A (carinata crosses). The: applied embryo culture increased the yield of hybrids and first backcross plants and reduced considerably the generation time.
Variation in Nicotine Content of Cultured Cell Lines of Nicotiana Species and their Somatic and Sexual Hybrids
Authors: Sabour M. , Simmonds J. , Setterfield G.
Published: April 2006

Several Nicotiana species, their intergeneric sexual and somatic hybrids were compared for their in vitro growth rate and nicotine content. Cell yield on a dry weight basis and HPLC analysis of their nicotine content revealed a very high variation within each cell line from parental, sexual and somatic hybrids for the two traits analyzed. The trigeneríc sexual hybrids (N. rustica × N. debneyi) × N. tabacum and only two of the N. rustica × N. tabacum somatic hybrid lines show a positive heterosis in nicotine content in vitro The in vitro growth rate and nicotine content did not demonstrate a statistically significant correlation.
Evidence for Monotelodisomics in Rye (Secale cereale L.)
Authors: Melz G. , Winkel A.
Published: April 2006

Monotelodisomics of chromosome arms 2RL and 6RL were observed in progenies of rye trisomics. The monotelodisomic of chromosome arm 6RL (2n = 13 + 6RL) is vital and is well transmitted through the pollen. In the progeny of monotelodisomic 2RL. (2n = 13 + 2RL) no monotelodisomic but one monotelotrisomic of chromosome arm 2RS (2n = 14 + 2RS), one trisomic with an aberrant chromosome consisting (if chromosome arm IRS and a part of chromosome arm 2RL (2n = 14 + 2RSL) and one double telotrisomic of chromosome 2R (2n = 13 + 2RS + 2RL) have been identified.
Variation of Telomeric Heterochromatin Among Inbred Lines in Diploid Rye (Secale cereale L.)
Authors: Pilch J. , Hesemann C. U.
Published: April 2006

The amount of Telomeric C‐heterochromatin was investigated in 20 inbred lines of rye and their open‐pollinated source cultivars. In this short communication only the banding pattern of the chromosomes in the lines is presented. The inbred lines had an amount of heterochromatin similar to the source cultivars. Both groups carried some chromosomes with small telomeric C‐bands. The individual source cultivars were composed of 2—4 karyotypes having different amounts of telomeric heterochromatin. Most karyotypes were also identified in the respective inbred lines. Results suggest that the in breed in i: process was not related to a reduction of telomeric C‐hetrerochromatin in rye chromosomes.
Salt Tolerance of an Amphiploid between Triticum aestivum and Agropyron junceum
Authors: Forster B. P. , Gorham J. , Miller T. E.
Published: April 2006

The main objective of this work is to demonstrate the expression of salt tolerance genes in a wheat‐Agropyron amphiploid. Salt tolerance tests were carried out on wheat varieties, ‘Chinese Spring,’ and ‘Glenn‐son 81’ the amphiploid between ‘Chinese Spring’ and A. junceum, A. junceum and amphiploid × wheat hybrids, Apart from germination in petridishes all other tests were carried out on plants grown in saline hydroculture tanks. Fresh weight measurements are given for stressed and non‐stressed plants as well as measurements of harvest ripe plants. The utility of A. junceum as a source of salt tolerance genes for wheat is discussed.
Trait Associations in Introgressed Populations of Pearl Millet
Authors: Bramel‐Cox P. J. , Andrews D. J. , Frey K. J.
Published: April 2006

Principal component analysis has been used in this study to describe the associations among 17 traits measured on progenies developed from matings of two adapted pearl millet inbreds with three exotic pearl millets. The exotic parents were a primitive I and race, a weedy relative, and a wild relative. The first three components were calculated for these matings and the associations defined. Correlations between these components and grain yield and growth rate were also determined. The first principal component described a hybrid index in five of the six matings, and a number of other complexes of traits were determined by this component or the other two. Some were common to several matings. The first three components accounted for only 50–60% of the total variability; thus no strong association of trans was found that would hinder recombination of parental types to select agronomically desirable segregates with high grain yield or growth rate.
Response to Mass Selection for Plant Height and Grain Yield in Amaranth (Amaranthus spp.)
Authors: Vaidya K. R. , Jain S. K.
Published: April 2006

Two landrace accessions of amaranth, UCC 192 (Amaranthus cruentus) and UCH 213 (A. hypochondriacus), were used in a mass selection experiment; five per cent of the tallest and highest yielding plants in both populations were selected for three cycles. Selection gain was largest in the first cycle for both traits. Realized heritability estimates for plant height were C.22 in the UCC 192 population and 0.49 in UCH 213, and 0.09 in both populations for yield. The results supported earlier findings for the existence of genetic variability within amaranth landrace populations.
Yield, Oil Content and Fatty Acid Composition Evaluated in Androgenetic Plants in Brassica juncea
Authors: George L. , Abraham V. , Suryavanshi D. R. , Sipahimalani A. T. , Srinivasan V. T.
Published: April 2006

Homozygous diploids were obtained through anther culture in Indian mustard, Brassier juncea, cultivar TM‐4, Seeds could be harvested from 97 such plants in the A; generation. The androgenetic lines were further selected and the yield and yield components were compared in the A4 and A5 generations, Androgenetic lines showed variations for most of the characters studied including seed oil content and fatty acid composition. However, it was possible to recover seven lines out of 25 which were equal in seed yield and three equal in oil content compared TO the anther donor parent TM‐4.
Variation in Nitrate Tolerance of Nitrogen Fixation in the Pea/Rhizobium Symbiosis
Authors: Jensen E. S.
Published: April 2006

The short‐term effects of nitrate on symbiotic nitrogen fixation were studied in six cultivars of pea (Pisum sativum L.) using two strains of Rhizobium leguminosarum. Plants grown symbiotically for three weeks, in order to eliminate the effect of NO3 on nodule formation, were exposed to nil, 5 or 15 mM NO3 for a period of seven days. Nodule mass, nitrogenase activity by acetylene reduction and the NO2 and NO3 concentrations in nodules were determined.

Exposure to nitrate reduced the total acetylene reduction activity (ARA) in all cultivars, and a significant cultivar × nitrate treatment interaction was found. Nitrate influenced the components of N2 fixation, nodule mass and specific ARA (ARA/mg nodule), differently within and among cultivars. Nodule mass was reduced in all cultivars, but a variation among cultivars in the degree of reduction was found. Nitrate also reduced the specific ARA to different extents in the cultivars‐ The specific ARA of nodules from NO3‐treated plants, expressed as per cent of the specific ARA of nodules from plants grown without NOT3 was negatively correlated with the concentration of NO3 in nodules. No relationship was found between the reduction of N2 fixation and the nitrite concentration in nodules.

The results indicate that it is possible to improve the nitrate tolerance of symbiotic N2 fixation of the established pea/Rhizobium symbiosis by selection of suitable host plants.
Production and Cytogenetical Analysis of a Rye‐Cytoplasmic Tetraploid Triticale
Authors: Melz G. , Schlegel R.
Published: April 2006

A rye‐cytoplasmic tetraploid triticale was found in Fs progenies of crosses between tetraploid rye‘No 1323’and hexaploid triticale‘KT 77′. In the tetraploid triticale, two complete rye genomes and two mixed wheat genomes, consisting of the chromosomes 1A. 2A, 4A, 7A, 3B, 5B, and 6B are present. The rye cytoplasm did not affect stability of rye chromosome pairing during metaphase 1, since rye chromosomes participated in pairing irregularities just as did wheat chramosomes, even on a larger scale. The fertility of F0, plants ranged from 0 to 75.6 %, always associated with high grain shrivelling. The analyzed pairing behaviour of induced triploid hybrids from crosses between the tetraploid triticale and diploid rye indicates the presence of at least one wheat‐rye translocation in one of the investigated triploid plants.
Callus Culture‐Derived Somaclonal Variation in the Tropical Pasture Legume Stylosanthes guianensis (Aubl.) Sw.
Authors: Godwins I. D. , Gordon G. H. , Cameron D. F.
Published: April 2006

Plants were regenerated from leaf‐derived callus cultures of five genotypes of Stylosanthes guianensis. There were substantial genotypic differences in morphogenetic potential, ranging from 95–100 % of cv.‘Graham' calh to less than 1% of cv,‘Oxley' calh forming shoots. A total of 1024 regenerants (SC1) were planted out, with 28.1 % surviving to set seed. Variant characters including albinism, reduced fertility, dwarfism and leaf morphology were observed. Variation in selfed progeny (SQ2) of 138 SC1 plants was assessed in a replicated field trial involving 2484 SO2 individuals. Variant phenotypes were observed in 55 (39.9 %) SC2 families. Many families were segregating for albinism, altered morphology or reduced fertility. Thirty families had lower yields than their parent and earlier and later flowering variants were found. Eight tetraploid families were identified. These were characterized by more erect habit, larger leaves, stems, flowers and seeds, reduced fertility and yield and a tendency to flower later.