bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hormonal Changes Associated with Growth and Development of Red Raspberries
Authors: VASILAKAKIS MILTIADIS D. , McCOWN BRENT H. , DANA MALCOLM N. 
Published: April 2006

AbstractAnalysis for gibberellin‐like substances (GA) and cytokinins in cold and non‐cold treated fall‐bearing and cold treated June‐bearing cultivars of red raspberries (Rubus idaeus L.) was made at the 10 and 20 node stages of growth (at 10 nodes, all plants were vegetative; at 20 nodes, only cold treated plants of fall‐bearing cultivars were flower induced).Quantitative changes in GAs, as analyzed by the lettuce hypocotyl bioassay, were observed only in flower induced plants. In fall‐bearing cultivars at the 20 node stage of growth, there was a 100% greater activity in cold than non‐cold treated plants. Likewise, cold treated plants had a 60% greater activity at the 20 than at the 10 node stage of growth.Major qualitative differences in GAs were observed between the 10 and 20 node stage of growth in cold treated fall‐bearing cultivars but not in cold treated plants of June‐bearing cultivars. Changes in compounds at Rf 0.3 and 0.5 accounted for 35 to 54% of the total increase in GA activity between flower induced and non‐induced stages of growth.Cytokinin activity tested by the tobacco callus bioassay was greater at the 20 than at the 10 node stage of growth in all cultivars and treatments. However, cold treated plants of the fall‐bearing type had 70% greater cytokinin activity than non‐cold treated plants at both stages of growth.It is suggested that gibberellins, possibly acting synergistically with cytokinins, are involved inflower induction in red raspberries.
Induction of Adventitious Buds on Buds of Norway Spruce (Picea abies) Grown in vitro
Authors: VON ARNOLD SARA , ERIKSSON TAGE 
Published: April 2006

AbstractResting vegetative buds of Norway spruce, Picea abies (L.) Karst., were induced to form adventitious bud primordia when cultured on medium ‐containing cytokinin. After transfer of the induced buds to medium lacking cytokinin, adventitious buds developed. The adventitious buds arose from meristems formed de novo in the needle primordia. No differences were found in the ability to form adventitious buds among buds collected from trees ranging from 5–50 years old.
Biochemical Changes in Excised Leaves of Oryza sativa Subjected to Water Stress
Authors: DWIVEDI S. , KAR M. , MISHRA D. 
Published: April 2006

AbstractExcised rice (Oryza sativa L. cv. Ratna) leaves were used to compare the changes in the levels of various biochemical intermediates and enzyme activities during senescence in turgid and water‐stressed conditions. Chlorophyll, total protein and soluble protein content decreased but α‐amino nitrogen content increased during the senescence of turgid leaves. In the leaves subjected to water stress, these changes were accelerated, the acceleration being greater with higher degree of water stress. Starch, soluble sugars, total carbohydrates and non‐reducing sugar content decreased during senescence of turgid leaves. Water stress accelerated the changes in the levels of starch and non‐reducing sugar, but the changes in the levels of soluble sugars and total carbohydrates were retarded. Reducing sugar content increased at first and then decreased in the turgid leaves, and water stress accelerated the change. The decline in the catalase activity and the increase in the peroxidase activity with time was faster in the water‐stressed leaves than in the turgid leaves. Acid inorganic pyrophosphatase activity increased, but alkaline inorganic pyrophosphatase activity decreased during the senescence of turgid leaves, and such changes were accelerated by water stress. The results suggest that water stress does not accelerate all the processes connected with leaf senescence.
The Relationship of Some Glycosidases to the Endogenous and IAA‐induced Growth of Light‐grown Cucumber Hypocotyls
Authors: KATSUMI MASAYUKI , YAMAMOTO YURI 
Published: April 2006

AbstractSome glycosidases in light‐grown cucumber (Cucumis sativus L. cv. Aonaga‐jibae) hypocotyl sections were examined with respect to their localization and relation to endogenous and IAA‐induced growth. Frozen‐thawed sections were used directly for measurement of enzyme activities, and β‐glucosidase, α‐ and β‐galactosidases and β‐xylosidase were assayed by using p‐ or o‐nitro‐phenylglycopyranosides as substrates. The order of the activity of these enzymes were β ‐glucosidase > β ‐galactosidase =α‐galactosidase > β‐xylosidase. No activity of α‐glucosidase was detected. High glycosidase activities were found in the youngest region of the hypocotyl, where the endogenous growth rate was highest. However, there was no significant difference in the activities of this region between seedlings at different growth stages. Among the enzymes tested, β ‐glucosidase showed a high correlation with the endogenous growth rate. β‐glucosidase was found to be mostly associated with the cell wall fraction, while β‐galactosidase was rather found in the soluble fraction of the cell. Separation of the epidermis from the section showed that a very high activity of β‐glucosidase was associated with the epidermis. In both whole sections and isolated cell wall fractions, IAA was shown to have no effect on the activities of β‐glucosidase and β‐galactosidase.
Conversion of Phosphatidyl Choline to Phosphatidic Acid in Freeze Injured Rye and Wheat Cultivars
Authors: HORVÁTH I. , VIGH L. , BELEA A. , FARKAS T. 
Published: April 2006

AbstractThe effect of exposure to freezing temperature (−15°C) on leaf phospholipid composition of hardened rye (Secale cereale L.) and hardened wheat cultivars (‘Miranovskaja 808’, ‘Bezostaja 1’, ‘Short Mexican’ and ‘Penjamo 62’), which differ in their resistance to frost, was investigated. Hardening took place under natural conditions. All the seedlings attained an equal level of linolenic acid in their leaves during hardening. Exposure to freezing temperatures resulted in a loss of phosphatidyl choline and accumulation of phosphatidic acid in the leaves. The ratio of phosphatidic acid to phosphatidyl choline, but not the level of poly‐unsaturated fatty acids in the leaves, was related to their ability to survive at low temperatures. As freezing injury is caused by the formation of ice crystals in both extra‐ and intracellular space, it is probable that the plasma membranes of the investigated cultivars differed with respect to their water permeability. It is concluded that the plants, depending on the degree of their resistance to cold, produce an unknown substance of lipidic nature upon exposure to cold, with the aid of which they adjust the transitional state of their membranes to the prevailing temperature and, at the same time, facilitate the efflux of water from the cells.
Cellulose Content in Fibers of Cottons which Differ in their Lint Lengths and Extent of Fuzz
Authors: BEASLEY C. A. 
Published: April 2006

AbstractThree cottons differing in their extent of fuzz fibers (linters) and final length of lint fibers were analyzed for amount of fiber cell walls and fiber cellulose at various times postanthesis. Cellulose determinations were performed directly on whole fibers and on fiber cell wall preparations. The data suggest that the presence of fuzz fibers does not account for a rise, followed by a plateau, followed by a rise, in cellulose content expressed as a percentage of cell wall material. It is concluded that: (1) under our greenhouse conditions, all fuzz fibers are initiated by day eight after anthesis; (2) weight per mm length of all fibers increases up to the point of secondary wall deposition and increases even more rapidly after that; (3) deposition of secondary wall cellulose in fuzz fibers probably does not begin until after similar deposition begins in lint fibers; (4) the actual amount of cellulose in primary walls of all elongating fibers (fuzz and lint) is a constant value, about 1 × 10−16 mg/mm; and (5) secondary wall cellulose deposition in lint fibers begins very sharply, in advance of cessation of elongation, at a time closely related to final lint fiber length. It is speculated that: (1) cell wall preparation procedures may remove significant amounts of noncellulosic wall material, thus making it difficult to define all functional constituents on the basis of what is left in a cell wall residue; and/or (2) primary walls may lose to the cytoplasm some of their constituents in advance of secondary wall deposition, the extent of loss varying due to developmental age of the elongating fibers.
Regulation of Rubidium Uptake in Sunflower Roots
Authors: PETTERSSON SUNE , JENSÉN PAUL 
Published: April 2006

AbstractUptake of Rb+was investigated in 12‐day‐old intact plants of sunflower (Helianthus annumL. var.californicus) which had been cultivated or pretreated in nutrient solutions with various K+concentrations. The relationship between Rb+influx and K+concentration of the roots indicated regulation of Rb+uptake by allosteric inhibition of the uptake mechanism. A constant passive influx occurred contemporaneously with the active uptake as shown by experiments at 0°C or with 2,4‐dinitrophenol. The allosteric regulation of ion carrier activity occurred after a time lag of up to 1 h after the change of external solution. In experiments involving Rb+treatments of K+‐deficient plants, the synthesis of carriers for transport of Rb+could be demonstrated. A model including allosteric regulation of Rb+uptake in roots is discussed.
Gibberellin‐Growth Retardant Interactions on the Growth and Flowering of Clerodendrum thomsoniae
Authors: KORANSKI D. S. , McCOWN B. H. , STRUCKMEYER B. E. , BECK G. E. 
Published: April 2006

AbstractGibberellin‐growth retardant interactions on the vegetative growth and flowering of the vine Clerodendrum thomsoniae Balf. were studied using both exogenous treatments and biologically testing the acid fraction attained from the plant extract. The growth retardant, ancymidol, greatly retarded stem elongation and markedly increased flowering under inductive environments. Gibberellin A3 (GA3) application to the shoot tip stimulated vine growth, prevented flowering under inductive environments, and completely overcame ancymidol‐induced effects. In contrast to GA3, treatment with GA7 had little effect on vegetative growth but increased flowering under inductive environments. The elevated activity of gibberellin‐like compounds, as determined by bioassay, were similar except for a marked increase in levels in ancymidol‐treated plants grown under inductive environmental conditions. Microscopic examination of the stem tip indicated that the action of the growth regulators involved the induction of floral buds. Thus, in Clerodendrum, ancymidol appears to stimulate an unknown gibberellin(s) and simultaneously acts antagonistically with GA3.
Influence of Rate of Development of Leaf Water Deficits upon Photosynthesis, Leaf Conductance, Water Use Efficiency, and Osmotic Potential in Sorghum
Authors: JONES M. M. , RAWSON H. M. 
Published: April 2006

AbstractThis study reports the effect of rate of development of leaf water deficits in soil‐grown sorghum (Sorghum bicolor) on the relationship of net photosynthesis, leaf conductance, and water use efficiency to leaf water potential, and on the degree of solute accumulation (osmotic adjustment). Recovery of these processes on rewatering, and responses during a second stress cycle were also studied. The most rapid rate of stress (1.2 MPa day−1) resulted in no solute accumulation and the lowest rate of net photosynthesis and leaf conductance for any given leaf water potential during stress. Stress at 0.7 and 0.15 MPa day−1 led to equal solute accumulations of approximately 0.6 MPa, but net photosynthesis, leaf conductance, and water use efficiency at a given leaf water potential were lower with the faster rate of stress (0.7 MPa day−1). Additionally, leaf conductance at a given leaf turgor potential was lowest at the 1.2 MPa day−1 stress rate, slightly higher at the intermediate rate of stress, and clearly highest at the slowest rate of stress. Recovery of both net photosynthesis and leaf conductance upon rewatering was rapid, taking less than 3 days, but full recovery of osmotic potential took between 6 and 11 days. One slow stress cycle had no influence on relationships during a second cycle. The concept of a threshold leaf water potential for stomatal closure is discussed and the conclusion reached that stomatal closure occurs slowly over a wide range of leaf water potential (> 1.0 MPa), the range being greater for slower rates of stress.
Physiological Characteristics of Mycosphaerella ascophylli, a Fungal Endophyte of the Marine Brown Alga Ascophyllum nodosum
Authors: FRIES NILS 
Published: April 2006

Abstract Mycosphaerella ascophylli Cotton, a fungal endosymbiont in the thallus of the marine brown alga, Ascophyllum nodosum (L.) Le Jol., was brought into axenic culture. Most of its nutritional requirements proved to be similar to those characteristic of marine saprophytic fungi: growth optimum at pH 7 to 8, good growth only with a high concentration of NaCl, ability to utilize nitrate as a nitrogen source and glucose, galactose and mannose as carbon sources. The fungus was more specifically characterized by a low temperature optimum (20°C, or lower), a requirement for both thiamin and biotin, and inability to metabolize xylose and fructose.
Correlation of the 680 to 672 nm Spectral Shift and the Halving of the Apparent Molecular Weight for Chlorophyll(ide) Holochrome from Barley
Authors: STUMMANN B. M. 
Published: April 2006

AbstractProtochlorophyll(ide) holochrome was isolated from dark‐grown barley (Hordeum vulgare L.) leaves and photoconverted. When the chlorophyll(ide) absorption maximum had decreased from 680 to 676 nm the preparation was chromatographed on a Sephadex‐gel column under conditions which strongly inhibited a further decrease in the absorption maximum. The absorption properties of the column fractions and the shape of the chlorophyll(ide) elution‐profile indicated the presence of two distinct chlorophyll(ide)‐bearing molecular species with apparent molecular weights of c. 74,000 and 29,000 and absorption maxima at 680 and 672 nm, respectively. It is concluded that: (1) no long‐lived species with intermediate absorption maximum is formed during the 680 to 672 nm shift of the absorption maximum of newly photoconverted holochrome; (2) no long‐lived pigment‐protein complexes with intermediate molecular weights are formed during the approximate halving of the molecular weight; (3) the shift in the absorption maximum and the decrease in molecular weight are closely correlated.
Cytology of Callus of Cryptomeria japonica
Authors: MEHRA P. N. , ANAND MANJU 
Published: April 2006

AbstractCallusing has been initiated from the cotyledons of 4‐week‐old seedlings of Cryptomeria japonica on Murashige and Skoog's medium supplemented with 22.8 μM IAA. Callus was grown successfully for more than 2 years on the same medium without any decline in growth vigour. The callus has shown differentiation of tracheids with reticulate thickenings but differentiation of root, shoot or whole plant has not yet been observed. Cytology of 2‐month‐old callus showed the presence of cells containing normal diploid chromosome complement of 2n = 22 and normal mitosis. However, the 6‐month‐old callus revealed majority of cells with normal diploid complement and the usual karyotype, but a few cells were noticed with aneuploid numbers ranging from 2n = 15–17. Anaphase bridges and lagging chromosomes have also been encountered.
Physiology of Rice Tungro Virus Disease: Involvement of Abscisic Acid‐Like Substance in Susceptible Host‐Virus Interactions
Authors: MOHANTY SUSANTA K. , MOHANTY SANTOSH K. , ANJANEYULU A. , SRIDHAR R. 
Published: April 2006

AbstractStunting was severe in susceptible rice (Oryza saliva L.) cultivar ‘Taichung Native 1’ infected with tungro virus (RTV) compared to less‐susceptible cultivar ‘IR 20’. The senescence of detached leaves of RTV‐infected susceptible cultivar incubated in water in dark was accelerated compared to the healthy leaves as measured by the loss of total chlorophyll content. The transpiration rate of RTV‐infected leaves of the susceptible cultivar was much lower than the healthy and RTV‐infected leaves of the less‐susceptible cultivar.Partially purified extracts obtained from RTV‐infected leaves effectively inhibited GA‐induced α‐amylase synthesis in barley endosperms, and rice seedling growth, and they accelerated senescence of detached rice leaves. In all the three bibassays the ABA‐like activity was significantly greater in the extracts from the RTV‐infected susceptible cultivar than in extracts from the less‐susceptible cultivar.
Nitrogen Stress in Birch Seedlings
Authors: INGESTAD TORSTEN , LUND ANN‐BRITT 
Published: April 2006

AbstractAn account is given of experiments with birch (Betula verrucosa Ehrh.), in which experiments there was optimum availability of all other nutrients, while nitrogen was added in amounts corresponding to optimum as well as various non‐optimum consumption rates. At the beginning of the growth period the nitrogen concentration in the nutrient solutions was very low or zero in the sub optimum treatments. In the optimum and supra–optimum treatments the nitrogen concentration in the solution was varied up to high levels. The nutrient solutions were not changed but the nutrients taken up were replaced by frequent additions. The sub‐optimum nitrogen additions were carried out every second hour in amounts increasing exponentially day by day, and with a varied exponent.During a lag phase the seedlings in the sub optimum treatments had rapidly diminishing growth rates, deficiency symptoms, and a relatively high root growth rate with formation of long, thin roots. When the growth rate later on had stabilized, a period was recognized during which measurements and sampling were carried out. At the end of the lag phase, or in the beginning of the experimental period, the nitrogen deficiency symptoms of the leaves disappeared and the various parts of the seedlings grew with the same rate, and in a good linear correlation with the rate of nitrogen supply.The results indicate that nitrogen primarily influences the leaf area growth rate, which responds rapidly to a change in nitrogen availability. The following general growth response demonstrates the ability of the plants to adapt growth according to nitrogen supply, so as to create stable internal physiological conditions. Thus, there is a close agreement between the rate of nitrogen supply and consumption on one hand and growth rate on the other.The characteristic nitrogen deficiency symptoms of the seedlings during the lag phase are very similar to those reported in the literature. During the stable period that follows, they disappear from the leaves in agreement with the fact that natural vegetation generally is green also when nitrogen is strongly growth limiting. It is concluded that the exponentially increasing amounts of nitrogen added to lie nutrient solution, also when the exponent is far below optimum, makes nitrogen available to the seedlings in a similar way as does the exponentially growing root system in. a solid medium. Birch seedlings are able to adapt growth rate to low nitrogen supply and thereby show a healthy appearance without acute deficiency symptoms. Some ecological and practical implications are discussed.
Effect of Light Intensity on Growth, CO2 Fixation, and Chlorophyll and Polar Lipid Production in Germinating Polytrichum commune Spores
Authors: KARUNEN PIRJO 
Published: April 2006

AbstractThe dry matter production in Polytrichum commune protonemata was increased when the light intensity was increased from 0 to 160 μE m−2 s−1, and at 160 μE m−2 s−1 production was about 200% of that found at 17 μE m−2 s−1. Production of chlorophyll (Chl) was increased by increasing light intensity from 0 to 17 μE m−2 s−1, but decreasing at light intensities above 17 μE m−2 s−1. At 160 μE m−2 s−1 the production of Chl was only about 50% of that at 17 μE m−2 s−1. The rate of CO2 fixation was low (0.31 μg CO2/mg Chi × h) at the light intensity of 17 μE m−2 s−1 as compared with that at 160 μE m−2 s−1 (0.83 μg CO2/mg Chi × h). Production of mono‐ (MGDG) and diglycosyl diglycerides (DGDG) was closely associated with that of chlorophylls. At the higher light intensity (160 μE m−2 s−1) production of glycolipids was about 60% of that at 17 μE m−2 s−1. Production of more polar lipids was less affected by light intensity. Light intensity also affected the fatty acid pattern of the lipid fractions. The effect was most pronounced in the MGDG fraction, where the proportion of C 18: 3ω3 + C 16: 3ω3 was higher at the higher light intensity.
Effect of Changed Environmental Conditions on Glycolipids of the Mosses Pleurozium Schreberi and Ceratodon purpureus
Authors: ARO EVA‐MARI , KARUNEN PIRJO 
Published: April 2006

AbstractThe effect of changed environmental conditions on the content of glycolipids and component fatty acids was studied in the moss species Pleurozium schreberi and Ceratodon purpureus. The mosses were collected from their natural habitats when frozen and covered by snow. After one week's exposure to rhythmic light (150 μE m−2 s−1, 12 h 17°C) no changes were observed in the absolute amount of fatty acids in either mono‐ (MGDG) or diglycosyl diglyceride (DGDG) fractions. Some changes were recorded in the content of individual fatty acids, however. The long chain, polunsaturated fatty acids (mainly 20:4ω6 and 20:5ω3 in P. schreberi and in addition 16:3ω3 and 18:3ω3 in C. purpureus) tended to decrease and the shorter chain, more saturated ones increased correspondingly. Under continuous light conditions (17°C) the total amount of fatty acids decreased in both MGDG and DGDG fractions, more significantly at 150 than at 75 μE m−2 s−1. This was due to the accelerated degradation and/or decreased synthesis of polyunsaturated fatty acids, which in this case was not totally compensated by the increase in shorter chain, more saturated ones.
The Intracellular Location of Particulate‐Bound Polyphenol Oxidase in Avocado Mesocarp
Authors: SHARON OSNAT , KAHN VARDA 
Published: April 2006

AbstractPolyphenol oxidase of avocado mesocarp exists in a supernatant and a participate fraction. Isolation conditions were sought where maximal polyphenol oxidase activity could be retained in the particulate fraction. More polyphenol oxidase was associated with the 270–2000 g pellet than with the 2000–12,000 g pellet.Analysis of the particulate polyphenol oxidase on linear sucrose density gradient revealed two relatively heavy peaks. The data showed that the major part of polyphenol oxidase was not a constituent of chloroplasts, chromoplasts or mitochondria. The closeness of the positions of polyphenol oxidase and of catalase in both the green and the yellow zones of the mesocarp established that most of the particulate polyphenol oxidase of avocado is associated with microbodies.