bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein Metabolism in Cultured Plant Tissues
Authors: KEMP JOHN D. , SUTTON DENNIS W. 
Published: April 2006

AbstractRates of protein synthesis in normal callus tissues (either tight or loose morphological form), in crown gall callus tissues and in cultured pith cells were measured for both the lower surface cells (those in contact with the original growth medium) and upper surface cells (those never in contact with the growth medium until labeling). Cells of both surfaces of loose and crown gall callus and the upper‐surface cells of tight callus had similar rates of protein synthesis, 29–31 mg of protein synthesized × (g protein)−1× h−1. The lower surface cells of tight callus had a 35% lower rate of synthesis, 20 mg × g−1× h−1.Pulse‐chase experiments suggested that rates of protein degradation for all tissues were the same, 21–23 mg protein × (g protein)−1× h−1. Thus, there probably was no accumulation of protein in the lower surface cells of tight callus tissue, but the other tissues had rates of accumulation equaling 10 mg × (g protein)−1× h−1. Autoradiography and electron‐microscopic examination of cells in tight callus labeled with 3H‐leucine show that: (a) the lower‐surface cells were more degenerate than cells within the callus or on the upper surface; and (b) the first few cell layers nearest the medium were preferentially labeled.Pulse‐chase experiments were also used to quantitate the nonprecursor pool (defined as that tritium in the soluble amino acid pool that does not equilibrate with protein during a pulse‐chase experiment). The nonprecursor pool increased linearly with time at the same rate as incorporation of 3H‐leucine into protein. Furthermore, the nonprecursor pool copurified with leucine and was probably either D‐ or L‐leucine.
Protein Metabolism in Cultured Plant Tissues
Authors: KEMP JOHN D. 
Published: April 2006

AbstractThe N‐trifluoroacetyl‐L‐prolyl‐leucyl methyl ester (TFA‐L‐prolyl‐leucine) was synthesized to quantitate the amounts of D‐ and L‐leucine in the amino acid pool fraction of tobacco callus tissue. TFA‐L‐prolyl‐D‐leucine and TFA‐L‐prolyl‐L‐leucine could be separated on gas liquid chromatography, with the former eluting about 45 s before the latter. The chromatographed TFA‐L‐prolyl‐L‐leucine was collected from the gas liquid chromatograph and found to contain equal molar amounts of leucine and proline. The identity of the two gas liquid chromatography peaks was confirmed by gas liquid chromatography/mass spectrometry.Although callus tissue incorporated both exogenously added D‐ and L‐leucine into its amino acid pool fraction, the rate of uptake of D‐leucine appeared to be substantially less than that of L‐leucine.When callus tissue was labeled on 3H‐L‐leucine medium for 24 h and then transferred to nonradioactive medium for 24 h, about 50% of the tritium remaining in the leucine pool was not available for protein synthesis (nonprecursor pool fraction). However, all of the tritium was associated with L‐leucine, and the specific radioactivity of leucine in collected TFA‐L‐prolyl‐leucine was the same as that of leucine in the crude pool fraction. Thus, the nonprecursor pool is L‐leucine.
Vegetative Propagation of Pinus sylvestris
Authors: WHITEHILL S. J. , SCHWABE W. W. 
Published: April 2006

AbstractMethods for the vegetative propagation of Pinus sylvestris L. from interfascicular shoots are described. Using 5‐year‐old plants the outgrowth of interfascicular shoots was promoted by removal of terminal and lateral buds; this response was augmented substantially by application of cytokinin, tri‐iodobenzoic acid, alar and morphactin alone and especially in combination.The rooting capacity of shoot cuttings from interfascicular shoots appeared to be largely determined by the state of growth of the stock plant. Cuttings from dormant stock plants subjected to short‐day treatment followed by a period of low temperature gave the best rooting, especially when the cuttings themselves had been cold‐stored prior to planting. Rooting was optimal when such cuttings were treated with a mixture of 25 mg/l of indolebutyric acid and 25 mg/l of napthaleneacetic acid as a 48 h basal soak, and were planted on a heated mistbench under extended illumination; over 90% of such cuttings could be rooted. These results are discussed in relation to bud activity, endogenous hormone levels and promoting tissue extracts also tested.
Purification and Partial Carbohydrate Analysis of Phytochrome from Avena sativa
Authors: ROUX STANLEY J. , LISANSKY STEPHEN G. , STOKER BLANCHE M. 
Published: April 2006

AbstractHighly purified samples of phytochrome from etiolated oat (Arena satira L.) seedlings were analyzed for sugar content. Phytochrome was found to be a glycoprotein, with about 4% of its weight as carbohydrate. In addition, modifications in the procedure for purifying phytochrome are proposed here and certain details about the protocol are discussed that improve the yield and reproducibility of previously published methods.
Two Steps of Gas Exchange in Leaf Photosynthesis
Authors: OGAWA TERUO 
Published: April 2006

AbstractPhotosynthesis and transpiration of excised leaves of Taraxacum officinale L. and a few other species of plants were measured, using an open gas analysis system. The rates of CO2 uptake and transpiration increased in two steps upon illumination of stomata‐bearing epidermis of these leaves at a light intensity of 50 mW × cm−2. Abscisic acid inhibited only the second step of gas exchange. Illumination of the astomatous epidermis of hypostomatous leaves caused only the first step of gas exchange. These data indicate that the first and second steps arise from cuticular and stomatal gas exchange, respectively. The rate of the cuticular photosynthesis in a Taraxacum leaf reached saturation at a light intensity of 5 mW × cm−2, and the rates of the stomatal photosynthesis and transpiration reached saturation at a higher intensity of 35 mW × cm−2. The cuticular photosynthesis of a Taraxacum leaf was 18% of the stomatal photosynthesis at 50 mW × cm−2 and 270% at 5 mW × cm−2. The other species of leaves showed the same trend. The importance of cuticular CO2 uptake in leaf photosynthesis, especially under low light intensity was stressed from these data.
Effect of Water Stress on Transpiration in Birch Seedlings
Authors: SMOLANDER HEIKKI , HARI PERTTI , LUUKKANEN OLAVI 
Published: April 2006

AbstractTranspiration of birch seedlings in the field is largely controlled by the amount of available water in the soil. This is in contrast with the situation found in CO2 exchange, where distinct interaction between temperature and drought was observed in our previous studies. The present study indicates that no similar relationships exist as far as transpiration is concerned, and in agreement with our previous preliminary studies, separate control mechanisms thus seem to affect transpiration on the one hand and photosynthesis on the other under natural conditions.
Proteins of Mitochondrial Synthesis
Authors: GOSWAMI BISWENDU B. , DUBE SYAMALIMA , BHATTACHARYYA PRABIR , SINHA SANDIP N. , RAY BIMAL K. , DUBE D. K. , ROY S. C. 
Published: April 2006

AbstractProteins synthesized in vitro by mitochondria isolated from 48‐h germinating seeds of Vigna sinensis (L.) Savi and incubated in the presence of 14C‐labelled amino acids from Chlorella protein hydrolysate, have been found associated with nine products separable by acrylamide gel electrophoresis in the presence of sodium dodecyl sulphate. Cytoplasmic contribution to these products was practically eliminated by the use of cycloheximide. Most of the radioactivity was incorporated into proteins having molecular weights between 10,000 and 65,000 as determined by comparing their electrophoretic mobilities with those of standard, reference proteins.
Regulation of Transpiration in Avena. Responses to White Light Steps
Authors: BROGÅRDH T. , JOHNSSON A. 
Published: April 2006

AbstractThe transient responses in transpiration rate of the primary leaf of 8‐days‐old oat plants were studied when step changes in the white light irradiance were administered to the plants. A light or dark step was achieved by an instant increase or decrease, respectively, of the irradiance on the leaf surface. Usually the light step responses consisted of one rapid response (rise time 1–2 min) and one slow response (rise time 5–10 min). The dark step response had a fall time of about 10 min.At a high irradiance level and in CO2‐free air the slow response disappeared. This could mean that the slow response is CO2‐controlled. The rapid response was still present under these conditions and is therefore probably caused by other processes than the slow response.In long time experiments several cycles of a circadian rhythm (period 26–28 h) could be followed in the light step responses. Thus the rapid response was small at that time of the day when the slow response was most pronounced and vice versa. The endogenous nature of the rhythm was established in phase‐shift experiments. It is concluded that experiments on stomatal dynamics must take circadian variations into account.
Glutamic Acid Dehydrogenase Activity in Linseed as Influenced by Plant Age and Photoperiod
Authors: SAIRAM R. K. , SIROHI G. S. , SRIVASTAVA G. C. 
Published: April 2006

AbstractGlutamic acid dehydrogenase (GDH) activity was measured in linseed Linum usitatissimum ev. SH‐1 at different growth intervals under normal and long photoperiodic conditions. In ungerminated seeds a low activity of GDH was recorded which increased rapidly during germination and thereafter decreased to a level when no GDH activity could be detected at 47 days of growth. An increase in its activity was recorded at 67, 87 and 107 days. Longer photoperiod (continuous light) increased the activity in roots markedly as compared to shorter photoperiods (normal days).
Properties of Extracellular Enzymes from Aphanomyces astaci and Their Relevance in the Penetration Process of Crayfish Cuticle
Authors: SÖDERHÁLL KENNETH , UNESTAM TORGNY 
Published: April 2006

AbstractIn culture filtrates from the crayfish plague parasite, Aphanomyces astaci, protease and a low level of hyaluronidase activity were found. The hyaluronidase activity was highest at pH 6.5 or above and at about 23°C. The protease activity had a broad pH‐optimum, between pH 7 and at least pH 10, and was partially denatured at 30°C. However, when incubated for 30 min with the substrate, casein, the activity increased logarithmically up to about 35–40°C and had an apparent optimum at 45–50°C.The proteases from the parasitic as well as from two less proteolytic, saprophytic Aphanomyces species were predominantly constitutive and were excreted mainly by the older mycelia. Proteases from the parasite and a saprophyte did not reach full activity until 10–30 min after substrate addition.No lipase activity was found in the case of the mycelium of the parasitic species. However, esterase was apparently present inside germinating zoospores.The native enzymes of A. astaci could degrade freeze‐dried soft cuticle from crayfish. The relevance of the different enzymes of A. astaci for the penetration process within the cuticle of crayfish is discussed.
In vivo Chlorophyll Fluorescence Monitoring with Solid State Photosensors
Authors: MELCAREK PETER K. , BROWN GREGORY N. 
Published: April 2006

AbstractSolid state photosensors with their many advantages have not been utilized for chlorophyll fluorescence research. One reason is their reputed low photosensitivity compared to photomultiplier tubes. A photodarlington sensor has a relatively low photosensitivity and a nonlinear current output versus light intensity. However, when incorporated into an apparatus described in this paper it can respond to fluorescence signals from leaves using light excitation as low as 500 μW/cm2. The sensitivity of another solid state device (photovoltaic photodiode) was compared to five photomultipliers using a monochromator‐microphotometer testing apparatus. This solid state sensor proved to have equal or greater sensitivity to chlorophyll fluorescence. An apparatus incorporating the photovoltaic photodiode is discussed.
Endogenous Shoot Growth Rhythms and Indeterminate Shoot Growth in Oak
Authors: BORCHERT ROLF 
Published: April 2006

AbstractWide variations of shoot growth patterns in saplings of pin oak (Quercus palustris Muenchh.) have been observed as a consequence of varying environmental conditions, experimental manipulations, and vigor of trees. Shoot growth patterns range from a series of recurrent, determinate flushes, constituting a genuine endogenous rhythm, to continuous, indeterminate growth. Observed growth patterns agree well with those predicted by a model of rhythmic growth which assumes the dependence of shoot growth on the functional equilibrium between shoot and root system. Indirect evidence suggests that cessation of shoot growth under favorable environmental conditions might be a consequence of internal water deficits. Observed differences in shoot growth patterns between young and mature trees are discussed as logical consequences of the model.
Tracheary Element Formation from Single Isolated Cells in Culture
Authors: TORREY JOHN G. 
Published: April 2006

AbstractFriable callus tissue of Centaurea cyanus L. was grown on a solidified synthetic nutrient medium (EBM‐1) to produce a tissue with a low frequency of differentiated tracheary elements. Tissues were then suspended in liquid nutrient medium with agitation to produce a suspension which was filtered and the single‐cell suspension resulting was used as inoculum for either cell suspension cultures or for plating of cells into solidified medium in Petri plates. Media for the suspension cultures were selected to favor cytodifferentiation of tracheary elements. Differentiated tracheary elements formed as early as 10 days and numbers of tracheary elements increased with time roughly in relation to the increase in total cell number. From plating experiments it was shown conclusively that single isolated parenchyma cells differentiated directly into single isolated tracheary elements, although this event was rare. More usual was the division of isolated cells to form small colonies and then the differentiation of one, several or all of the cells into tracheary elements. Comparisons are made between results with cell plating experiments and cell suspension cultures. Optimism is expressed for finding a cell suspension culture system for studying cytodifferentiation.
Physiological Changes during Protoperithecial Differentiation in Neurospora tetrasperma
Authors: VISWANATH‐REDDY M. , TURIAN G. 
Published: April 2006

AbstractProtoperithecial differentiation in Neurospora tetrasperma proceeds in four clearly discernible stages: ascogonial bud, ascogonial hook, ascogonial coil, and protoperithecium. This morphogenetic sequence was completely but transitorily blocked at 37°C. Under low oxygen tensions or in the absence of carbon dioxide, only ascogonial coils were differentiated. Glycolytic inhibitorssuchas2‐deoxy‐D‐glucose interfered with the ascogonial differentiation. Citric acid cycle inhibitors such as fluoroacetate selectively blocked the further development of ascogonial coils into protoperithecia. Differentiating cultures at 25°C responded positively to external sucrose with respiratory quotients above 1.0, whereas non‐differentiating cultures at 37°C, although respiring at high rates, never reached RQ 1.0. These results indicate that carbohydrate metabolism via fermentative glycolysis functions normally in ascogonia differentiating (25°C) cultures only.Comparative chemical analysis showed delayed RNA synthesis, sharp disturbances in protein biosynthesis and metabolism, and lower levels of carbohydrate and bound lipids in young cultures at 37°C.Polyols, especially ribitol and xylitol utilized as sole source of carbon, induced abundant protoperithecial morphogenesis at 37°C. This alleviating effect of polyols was negated by the addition of sugars at 37°C and shown to be a specific metabolic effect.
Bleach‐induced Germination and Breakage of Dormancy of Seeds ofAlectra vogelii
Authors: OKONKWO S. N. C. , NWOKE F. I. O. 
Published: April 2006

AbstractThe effects of solutions of sodium hypochlorite and calcium hypochlorite (bleach) on dormancy and germination ofAlectra vogeliiseeds were investigated. Dry (non‐pretreated) and 10‐day water‐pretreated seeds were exposed to various bleach concentrations, as well as to the host (Vigna unguiculata) root exudate.The 15‐month‐old Alectra seeds used were partially dormant in that only 40% or less of the 10‐day pretreated seeds could be stimulated to germinate by the standard host root exudate. Comparable percentage germination of nonpretreated seeds was achieved with certain concentrations of bleach and the halogens, chlorine and bromine. Bleach and the halogens served not only as germination stimulant for pretreated Alectra seeds but appropriate concentrations induced also high percentage (70–90%) germination indicating a breakage of seed dormancy as well. The activity of the bleach in stimulating high percentage germination could be significantly reduced when the optimally bleach‐treated seeds were rinsed daily with water during the germination period. Vigna root exudate, but not bleach, was shown to act as root stimulant for Alectra seedlings. The possible mechanism of the bleach effect on germination and dormancy of Alectra seeds is discussed.
Indole‐3‐Acetic Acid (IAA) Oxidation by Leghemoglobin form Soybean
Authors: PUPPO ALAIN , RIGAUD JEAN 
Published: April 2006

AbstractLeghemoglobin from nudules of soybean prepated by ammonium sulfate frationation appeared to be able to destroy substantial quantities of IAA, Degradation still occurred in purified leghemoglobin preparations isolated by G‐100 Sephadex chromatography. Nicotinic acid and acetate affecting the conformation of leghemoglobin both inhibited IAA oxidation by this hemoprotein. The ferric form was found to be the most active in this catabolism. This oxication, related to the psedudoperocidase activity of leghemoghlobin, is undoubtedly restricted in vivo by the very low level of the ferric form present in efficient nodules.
The Reducing Power and the CO2 Fixation Activity of Isolated Choroplasts
Authors: MIGINIAC‐MASLOW M. , HOARAU A. 
Published: April 2006

AbstractAntimycin A, which stimulates the Co2 fixation activity of isolated intact spinach (Spinacia oleracea L) chloroplasts, was shown to stimulate also the oxygen evolution in the presence of oxaloacetate, as do the uncouplers. Some uncoupers (tetramethlethylenediamine, Nh4CL) were shown to stimulate the CO2 fixation activity, and to decrease the intrachloroplastic ATP levels, like antimycin A. The intrachloroplastic NADPH levels were not affected by the inhibitors studied.
Influence of Ethidium Bromide on the Gibberellin‐Induced Elongation of Cucumber Seedlings
Authors: SNIR IONA , KESSLER BEZALEL 
Published: April 2006

AbstractEthidium bromide, a DNA intercalating agent, acts synergistically with gibberellin on the elongation of cucumber seedling hypocotyls at concentrations of 0.05 and 1.0 μg per plant. At higher concentrations and when given prior to the GA treatment, ethidium bromide acts antagonistically with gibberellin.
Ribonucleic Acid Synthesis in Plant Mitochondria: Effects of Some Inhibitors and Cyclic Nucleotides
Authors: GOSWAMI BISWENDU B. , DUBE D. K. , ROY S. C. 
Published: April 2006

AbstractMitochondria isolated from 48‐h germinating Vigna sinensis (L.) Savi can incorporate [3H]uridine into acid‐insoluble material. The incorporation is highly sensitive to rifampicin and partially so to ethidium bromide, two specific inhibitors of template function. The inhibitory effect of rifampicin can be partly counteracted by cyclic 3′:5′‐AMP but not by cyclic 3′:5′‐GMP, if they are allowed to interact with the synthetic system before the treatment with rifampicin. This indicates that cyclic AMP and rifampicin compete for a common site on the RNA polymerase responsible for DNA‐dependent RNA synthesis. Inhibition by ethidium bromide is unaffected by prior nucleotide interaction with the system.
Differectial Induction of Zoospore Encystment and Germination in Aphanomyces astaci, Oomycetes
Authors: SENSSON EBBE , UNESTAM TORGNY 
Published: April 2006

AbstractGenmination and encystment of zoosspores of Aphanomyces astaci, the very serious pathogen of European freshwater crayfish, Astacus astacus, were studied in ritro.Encystment of motile zoospores was achieved using mild heating, stirring, or addition of alkali metal chlorides or mannitol. The physical treatments were inhibitory to the subsequent germination, while encytment could be achieved with potassium chloride, indicating that the two processes are differently induced and can be studied separately. The effect of temperature on these processes was also somewhat different.Some ionic substances drastically influenced the final shape of the cyst. but without noticeably influencing the subsequent germination.Germination was induced by a short exposure to the stimulatory substances. A synergistic effect between ionic and non‐ionic compounds was found. The receptivity of the zosspores to the triggering substances was low in newly formed spores but increased during the first 3 h of motility.The initiation of germination is suggested to be parltly to be partly due to an osmotic effects on the zoospore. The relevance of the experimental results to in vivo conditions in discuessd.
Potassium and Photosynthesis in the Marine Diatom Phaeodactylum tricornutum as Related to Washes with Sodium Chloride
Authors: OVERNELL JULIAN 
Published: April 2006

AbstractThree washes of Phaeodactylum tricornutum with potassium free sodium chloride solution reduced the potassium content of the cells to approximately 7% of the control value at pH 7.0. There was a concomitant reduction of the light induced evolution of oxygen to a value of approximately 20% of the control value. This reduction was less at pH 8.0. Addition of potassium to the washed cells gave rise, after 15 min, to a partial regain of the photosynthetic activity and of cellular potassium.Activities of the two photosystems as assayed here were not dependent on the maintainance of a high potassium content in the cells. The level of ribulose‐1,5‐diphosphate carboxylase activity was the same whether the cells had been washed with potassium free or potassium containing saline.Ruptured cells rapidly lost their ability to catalyse the photoreduction of dichlorophenolindophenol by water.
Reproducibly High Plating Efficiencies of Isolated Mesophyll Protoplasts from Shoot Cultures of Tobacco
Authors: BINDING H. 
Published: April 2006

AbstractSterile shoot cultures of Nicotiana tabacum L. cv. Sansum proved to be a highly appropriate source for the isolation of viable protoplasts. High yields of isolated protoplasts and high plating efficiencies are guaranteed by the absence of contaminaction, by controlled culture conditions and by the rhythmic rejuvenation of the shoots at each transfer to fresh agar medium.
Influence of S‐ethyl dipropylthiocarbamate (EPTC) on Wheat Root Phospholipid Fatty Acid Composition
Authors: KARUNEN P. , WILKINSON R. E. 
Published: April 2006

AbstractWinter wheat (Triticum sativum L. ev. Nisu) was grown in sand which contained 0, 0.25, 0.5 and 1.0 mg S‐ethyl dipropylthicarbamate (EPTC) per kg air dry sand. In 21 day old roots, the phospholipids (PL) were extracted in ice‐cold chloroform/methanol (2:1, v/v) and isolated by thin layer chromatography (TLC). The PL fatty acids were analysed by gas liquid chromatography (GLC). The major fatty acids of the root PL fraction were palmitic, oletic, linoleic, and linolenic (22.4, 6.8, 39.2, and 23.1 μ/g root fresh weight, respectively). Total fatty acid content of the PL fraction was decreased to 39% by 1 mg EPTC/kg sand in which linolenic acid was decreased to 28%. The remainder of the major fatty acid constituents were decreased to 12–47%. The general quality of fatty acids in the PL fraction was slightly altered, while a 60% inhibition of total PL production resulted.