bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Yield Isolation of Nuclei from Plant Protoplasts
Authors: ZUILY‐FODIL Y. , PASSAQUET C. , ESNAULT R. 
Published: April 2006

AbstractNuclei were isolated from protoplasts obtained from Parthenocissus tricuspidata Crown Gall callus tissues. The effect of various isolation procedures, detergent or ultrasonication, on yield and quality of nuclei was studied. A standard procedure, based on the use of 5 × 10−3% Triton × 100 — 6% PVP — 20% glycerol, may be carried out in 30 min and gives 80 to 90% yield of nuclei in which RNA polymerase activity is retained.
Mouvements nycthéméraux foliaires chez le Cassia fasciculata inversé dans le champ de la pesanteur
Authors: GAILLOCHET JACKY 
Published: April 2006

Abstract Nyctinastic movements of leaves of Cassia fasciculata inversed in the field of gravity.Plants of Cassia fasciculata Michx, were grown under controlled conditions with a diurnal rhythm of 14 h light and 10 h dark. The nyctinastic movements performed by the leaves were observed by time lapse photography, on plants inverted in the field of gravity and compared to those recorded on plants remaining in natural position. The movements were observed on leaves from which the petiolar gland has been removed as well as on leaves in which it has been preserved.In plants inverted in the field of gravity, the leaflet movements were not disturbed but the petiolar ones were opposite to those observed on plants in natural position and smaller in amplitude (52 and 15 degrees difference between maximum and minimum positions respectively). This was not influenced by the removal of the petiolar gland. Inverting plants greatly shortened duration of closing and time spent maximally closed while increasing both duration of opening and time spent maximally opened. Removal of the petiolar gland did not influence the opening‐closing schedule of the plants in normal position but in inverted plants it caused marked changes in this schedule.These results are discussed in connection with what is known about IAA. K+ and amyloplasts and their role in causing changes in pulvinus turgor.
Quantum Requirements of Photosynthetic Electron Transport In Sitka Spruce from Different Light Environments
Authors: LEWANDOWSKA M. , JARVIS P. G. 
Published: April 2006

AbstractQuantum requirements of photosynthetic electron transport have been measured in shoots of Picea sitchensis (Bong.) Carr. (Sitka spruce) from different levels in a forest canopy and in shoots from plants grown in contrasting light environments in controlled environment chambers. Neutral density filters were used to obtain very low photon flux densities. The light absorbed by the chloroplast suspensions was calculated from measurements of the transmittance of the suspensions. The shoots from the top of the forest canopy (“sun” shoots) had lower quantum requirements for photosystems I and II than the shoots from the bottom of the forest canopy (“shade” shoots). High light grown plants and “sun” shoots had higher rates of electron transport at light saturation than low light grown plants and “shade” shoots. Thus a higher potential for electron transport was found to exist in “sun” shoots than in “shade” shoots at both high and low photon flux densities.
Sterols in Germinating Seeds and Developing seedlings of Longleaf Pine, Pinus palustris
Authors: Van VU Cu , BIGGS Robert H. 
Published: April 2006

AbstractSterols in germinating embryos and young seedlings of longleaf pine (Pinus palustris Mill.) were identified and quantities determined for different periods after germination. Sterol analyses were performed by gas‐liquid chromatography (GLC) and verified by combination of GLC‐mass spectrometry. Campesterol and β‐sitosterol were two major sterols which accounted for most of the sterol composition while stigmasterol was present in very small amounts. No cholesterol was revealed by GLC‐mass spectrometry although there was a minor peak appearing on the sterol gas‐liquid chromatograms with a retention time close to that of authentic cholesterol. By fractionation, three different forms of sterols were obtained: steryl esters, steryl glycosides, and free sterols. The sterols were mainly found in the esterified fraction, while steryl glycosides and free sterols only made up a small portion of the total sterol value. The total sterol content in general increased during seedling development, and this increase reflected mainly a change in steryl esters. The low levels of both free and glycosidic sterols remained nearly unchanged throughout the experimental germination period.
The Role of Lipids and Proteins in the Mechanism of Latex Vessel Plugging in Hevea brasiliensis
Authors: SHERIEF P. M. , SETHURAJ M. R. 
Published: April 2006

AbstractThe phospholipid content of the bottom fraction of latex as well as the neutral lipids of rubber particles were determined in thirty‐one clonal mother trees of RRII clones of Hevea brasiliensis Muell. Arg. Ratios between cationic proteins and anionic proteins in the B‐sera, which is the sera contained in the lutoid particles in latex, obtained from clones RRIM‐501, PB 6/9, RRII‐105 and Tjir‐l were determined by electrophoresis. The influence of these factors on plugging index (a measure of the magnitude of latex vessel plugging) was investigated. Lutoid instability, as indicated by bursting index, is negatively ocrrelated with the phospholipid content of the bottom fraction of latex. The neutral lipid content of rubber particles is positively correlated with the colloidal stability of latex. The latex vessel plugging during latex flow is found to be negatively correlated with both the lutoid stability and the neutral lipids in the rubber particle. A high ratio of cationic and anionic proteins in B‐serum may also enhance the process of plugging.
Sporulation and the Macromolecular Composition of the Mycelium and Arthrospores of Geotrichum candidum
Authors: ALLERMANN K. , FLOTO F. , OLSEN J. , SORTKJær O. , KIER I. 
Published: April 2006

AbstractIn submerged culture the mycelium of Geotrichum candidum breaks into fragments (arthrospores) which are either cylindrical or ellipsoidal in shape; the proportion of each spore type depends upon the glucose concentration in the medium. Above 0.2% glucose the ellipsoidal type prevails, whereas the cylindrical type is more abundant at lower glucose concentrations. The cylindrical spores and the mycelium have a very similar macromolecular composition, but the ellipsoidal spores have less RNA and protein and more carbohydrate than the mycelium.
The Promotive Effect of Purine and Pyrimidine Bases in Rooting Hypocotyl Cuttings of Phaseolus mungo in Relation to Auxin and Nutrition
Authors: BHATTACHARYA SHEILA , BHATTACHARYA N. C. , NANDA K. K. 
Published: April 2006

AbstractExogenously supplied nitrogenous bases in combination with IAA + sucrose hastened the formation of roots on hypocotyl cuttings of Phaseolus mungo L. cv. G31. While purine and pyrimidine bases had little effect when used alone, together with IAA or sucrose they increased the number of roots and the effect was even more pronounced in combination with (IAA + sucrose). By contrast, guanine inhibited rooting completely in higher concentrations even in combination with (IAA + sucrose), and cuttings died within 48–72 h.
Thymidine Phosphorylation in Arachis hypogaea by Combined Activities of Adenosine Triphosphate Phosphohydrolase and Nucleoside Phosphotransferase
Authors: MULLIN BETH C. , FITES ROGER C. 
Published: April 2006

AbstractExtracts from hypocotyls of germinating peanuts (Arachis hypogaea L.) stimulated the formation of thymidine monophosphate from thymidine and adenosine triphosphate in the presence of magnesium ions. Such extracts were incapable of incorporating isotopic phosphorus from gamma‐labelled adenosine triphosphate into thymidine during the synthesis of thymidine monophosphate but were competent in transferring phosphorus from alpha‐labelled adenosine triphosphate to thymidine. The apparent thymidine kinase activity thus appeared to result from the combined activities of an adenosine triphosphatase (adenosine triphosphate pyrophosphohydrolase, E. C. 3.6.1.3) and a nucleoside phosphotransferase (E. C. 2.7.1.77). The latter two enzymes could be largely separated by using DEAE‐Sephadex chromatography.
Membrane ATPase Activity of Barley Roots and Potassium Uptake by Isolated Stele and Cortex
Authors: NASSERY H. , VALAMANESH A. 
Published: April 2006

AbstractUptake of potassium ions by isolated stelar tissues of barley from 0.5 and 10 mM K+ was respectively 13 and 3.6% of that of the cortical tissues. 0.1 mM H2PO4, LO mM ATP and 10 mM Ca(NO3)2 did not increase the potassium uptake of either stele or cortex during 5 h of uptake period.A time‐course incubation for histological demonstration of the ATPase activity of the plasmalemma and tonoplast of the matured sections of the roots demonstrated a greater activity for the cortical than the stelar tissue. In the stelar parenchyma cells, the plasma lemma showed a higher activity than the tonoplast. These results, which support the “leakiness hypothesis” of the stele, are discussed in relation to the proposed mechanisms of radial ion transport in roots.
Effects of pH on Georeaction and Elongation of Maize Root Segments
Authors: GABELLA MAURO , PILET PAUL EMILE 
Published: April 2006

AbstractThe pH effect was analysed in relation to the georeaction and the elongation of apical maize root segments. Two kinds of citrate‐disodium phosphate buffers were used for pretreatment and application on the fresh cut section of the segments. Both reactions to gravity and to growth seem to be more affected by the buffer components than by the proton concentration. Such results were confirmed by the comparison of several buffers.
Temperature and Light Requirements for the Sprouting of Chilled and Unchilled Tubers of the Purple Nutsedge, Cyperus rotundus
Authors: SHAMSI S. R. A. , AL‐ALI F. A. , HUSSAIN S. M. 
Published: April 2006

AbstractMature and immature tubers of purple nutsedge (Cyperus rotundus L.) chilled at 0°C in dry and wet conditions, were sprouted along with fresh, unchilled tubers over a range of temperatures (10°C‐45°C) in light and darkness. Fresh immature tubers showed a high sprouting percentage at all temperatures between 20°C and 40°C, while the mature ones did so only at 30°C and 35°C. Chilling of dry tubers stimulated early sprouting and increased the maximum sprouting percentage of both the mature and immature tubers. Dry chilling also lowered the limit of favourable temperatures to 15°C in the case of mature tubers. Chilling of wet tubers had a depressing effect and no sprouting occurred below 30°C.At all temperatures, light apparently favoured the sprouting of both the mature and immature tubers (except mature wet‐chilled ones at 35°C and 40°C). Immature tubers showed relatively higher sprouting percentage than the mature ones, both in light and darkness. Alteration of temperature requirements due to dry and wet chilling of the tubers is regarded as significant and functional in relation to the ecology of the species.
Chlorophyll Destruction in Lemon Fruit by Light and 2′,4’Dichloro 1‐Cyanoethane‐sulphonanilide
Authors: HALL A. E. , COGGINS C. W. 
Published: April 2006

AbstractChlorophyll content decreased when excised lemon fruits were exposed to light. A quantitative model for the photodestruction of chlorophyll exhibited reasonable agreement with data on in vivo destruction of chlorophyll. Photodestruction of chlorophyll was enhanced by treating fruit with 2′,4′‐dichloro‐l‐cyanoethane‐sulphonanilide (R33417). Measurable enhancement of chlorophyll destruction was observed with concentrations of R33417 as low as 10 μg/l. Maximum activity was achieved at approximately 600 μg/1. R33417 treatment enhanced photodestruction of chlorophyll to a greater extent at higher photon flux densities.
Light and Branch Formation in the Alga Vaucheria dichotoma (Xanthophyceae)
Authors: ÅBERG HÅKAN 
Published: April 2006

AbstractBranches of Vaucheria dichotoma (L.) Ag. were induced in two ways: by cutting, which led to a branch in the wound area and by exposure to light.Blue and red light were most active in branch formation. The light intensity dependence and the action spectrum of branch formation showed patterns similar to those of photosynthesis. Photosynthetic involvement was also indicated by the DCMU inhibition of branch formation. Elongation‐branching studies at different photoperiods showed that branching was increased by the presence of more photosynthetic light than was necessary for elongation.It may be concluded that photosynthesis exerted the main control of the branch formation of V. dichotoma. However, the action spectrum of branch formation showed a higher efficiency in blue light than would be expected from the action spectrum of photosynthesis. It is therefore possible that apart from the main induction via the photosynthetic pigments, other blue light sensitive pigments may have a regulatory effect.Far‐red light treatment of filaments pre‐exposed to 8‐h and 16‐h light periods did not affect branch formation. Spectrophotometrical detection of phytochrome was not successful. This may indicate that there is no participation of phytochrome in branch formation.I am indebted to Dr. Lisbeth Fries for her interest. I also wish to thank Prof. Lars Olof Björn and his friendly staff at the Institute of Plant Physiology at the University of Lund, where some of the experiments were carried out. I am grateful to AB Tomaso Minori for revising the English test and to Miss Inga‐Britt Jansson for typing it.The investigation was supported financially by a grant to Dr. Lisbeth Fries from the Swedish National Science Research Council.
Inhibition of Etiolation in Spirogyra by Phytochrome
Authors: VIRGIN HEMMING I. 
Published: April 2006

AbstractCells of Spirogyra filaments grown in darkness become longer than light grown cells. This elongation can be prevented by a few minutes of red light given with intervals of 24 h under the dark period. Far‐red light given after the red light pulse counteracts the red light effect. Cells which have finished their elongation in light do not elongate further in darkness. Along with the cell elongation the chloroplasts become less spirally wound and ultimately shortened to straight bands.
The Aetiology of Vascular Discoloration in Cassava Roots after Harvesting: Development of Endogenous Resistance in Stored Roots
Authors: MARRIOTT J. , BEEN B. O. , PERKINS C. 
Published: April 2006

AbstractThe susceptibility of cassava roots, Manihot esculenta Crantz, to vascular discoloration beneath two types of injury site, transverse cuts and periderm injuries, was compared for freshly harvested and stored roots. Susceptibility beneath transverse cuts changed rapidly, so that roots stored at ambient temperature for 5–9 days were largely resistant to vascular discoloration beneath this type of injury. Susceptibility to localized deterioration beneath periderm injuries changed more slowly, but significant decreases were observed in roots stored at ambient temperature for 10–16 days. Changes in susceptibility were observed in all cultivars tested, seven in Colombia and one in Jamaica. These changes were retarded but not prevented by storage at 2°C and by storage in sealed polyethylene bags. Pruning plants 1 to 3 weeks prior to harvesting, which has been shown to reduce the rate of post‐harvest deterioration of roots, was also found to reduce the susceptibility of roots to vascular discoloration beneath injuries made immediately after harvesting. Water loss through injuries caused a respiratory response as well as vascular discoloration. This respiratory response was as large in stored (resistant) roots as in freshly harvested (susceptible) ones. The potential of cassava roots to develop endogenous resistance to vascular discoloration either before or after harvesting is discussed in relation to the problems of storage of harvested cassava roots.
Abscisic Acid Inhibition of Kinetin Nucleotide Formation in Germinating Lettuce Seeds
Authors: MIERNYK J. A. 
Published: April 2006

AbstractImbibing ‘Grand Rapids’ lettuce (Lactuca saliva L.) seeds take up 14C‐kinetin, and metabolize this cytokinin to the 5′‐nucleotide. The identity of the labeled nucleotide in seed extracts was verified by Sephadex LH‐20 column chromatography, paper and thin layer chromatography, and high voltage paper electrophoresis.Incubations with kinetin in the presence of abscisic acid lead to an apparent specific inhibition of kinetin nucleotide formation. ABA has no effect on kinetin uptake, and does not inhibit kinetin nucleotide synthesis in vitro by a cell‐free preparation from lettuce seeds. Additionally, ABA does not inhibit adenylate synthesis from exogenously supplied adenine. These results represent a specific cytokinin‐ABA interaction, which might play a significant role in the hormonal regulation of lettuce seed germination.
Cytokinins and Senescence in Lemon Leaves
Authors: ILAN I. , GOREN R. 
Published: April 2006

AbstractThe effect of leaf age on cytokinin level was studied in Citrus limon (L.) Burm. f. cv. Eureca. It was found that mature 1‐year‐old leaves and senescing 2‐year‐old leaves contained considerably more cytokinins than young 3‐month‐old leaves. No consistent distinct decrease in cytokinin activity was revealed when the leaf passed from the mature to the senescing state. It was concluded that the results cannot be regarded as supporting the hypothesis that leaf senescence is brought about, at least partially, by a decrease in the level of its cytokinins.
Abscisic Acid and Gibberellic Acid Contents in Ripening Barley Seeds
Authors: SŁOMIŃSKI B. , REJOWSKI A. , NOWAK J. 
Published: April 2006

AbstractThe ABA and GA3 contents were investigated in barley seeds during maturation and after harvest. The highest amount of ABA was found in milk and wax ripeness – 13 ng and 11 ng per seed respectively. The level decreased during the later stages of maturation and during release of dormancy and was 1 ng per seed 6 weeks after harvest.The content of gibberellic acid decreased in a similar way but in an earlier stage of maturation. The determined amounts of GA3 were: 0.4, 0.1, 0.03 and about 0.05 ng per seed respectively, in milk, wax and full ripeness and after harvest.The results of quantitative determination, obtained with the GLC method, corresponded to the growth effects in the test of the first leaf of oat.
Translocation of 14C‐Assimilates in Roses
Authors: MOR YORAM , HALEVY ABRAHAM H. 
Published: April 2006

AbstractMovement of 14C‐assimilates from young and mature leaves to young rose shoots (Rosa hybrida cv. Marimba) was examined in two developmental stages.In the first stage after bud breaking the young shoot, especially its tip, depends for its supply of assimilates mainly on the mature foliage. At this stage young leaves are powerful sinks and retain 97% of their own photosynthates. The translocated 3% move mainly to the roots. At a later stage, just after the appearance of the flower bud, most of the leaves on the shoot become a source. The upper leaves supply assimilates to the flower bud and to the upper part of the stem. The 14C‐assimilates from the lower leaves move in two directions, the larger part being directed downward.
Effects of Kinetin on Transpiration Rate and Abscisic Acid Content of Water Stressed Young Wheat Plants
Authors: BENGTSON CURT , FALK STIG OLOF , LARSSON STIG 
Published: April 2006

AbstractEffects of kinetin on transpiration rate and abscisic acid content were determined. Leaves from 9‐day‐old wheat plants (Triticum aestivum L. cv. Weibull's Starke II) were used. —Transpiration rate decreased in excised leaves put in water, but it was maintained at a higher rate when kinetin was supplied. When excised leaves were water stressed by air‐drying for 1 h, addition of kinetin resulted in a considerable stimulation of transpiration rate. The effect reached its maximum after 15 h and this level remained relatively unchanged for at least 10 h. Intact seedlings which were stressed before leaf excision, showed only a slight stimulation of kinetin on transpiration rate. — Abscisic acid content slowly increased up to three‐fold in 2 days in excised leaves put in water. In excised and water‐stressed leaves the abscisic acid content was reduced during the first 24 h and then increased. As the leaves were fully turgid, the increase could not have been caused by water stress. However, both in stressed and unstressed leaves kinetin addition reduced the increase in abscisic acid content. — It is suggested that the stimulation by kinetin on transpiration rate in excised and water stressed leaves was mainly due to the combined effect of (1) a reduction in the activity of endogenous cytokinins, (2) kinetin acting as a ‘substitute’ for the inactivated cytokinins but exerting a stronger effect on transpiration than the endogenous cytokinins, and (3) the ‘extra’ reduction in abscisic acid content caused by the kinetin treatment. Furthermore, the results indicate that changes in cytokinins might be partly responsible for the aftereffect on transpiration.
Promotion of Flowering in the Pinaceae by Gibberellins
Authors: ROSS STEPHEN D. , GREENWOOD MICHAEL S. 
Published: April 2006

AbstractGibberellins (GAs) were effective in promoting flowering in sexually mature (45‐year‐old scions) grafts of loblolly pine (Pinus taeda L.). Seed‐cone production was increased 12‐fold in field‐grown, grafted ramets by bi‐weekly, May‐September applications of 500 μg per branch of GA4/7. Gibberellin A3 was equally effective at 500 μg but not at 100 μg per branch, while GA5 was ineffective at either concentration. A second study using potted, less‐sexually mature (8‐to 10‐year‐old scions) grafts gave a reduced level of seed cones in response to GAs. However, even on these younger grafts GA4/7 was a significant promotive treatment, GA3 being considerably less effective. Branch girdling, tested as an adjunct treatment, was ineffective. It is now apparent that exogenous applications of GA4/7 are effective on a number of Pinaceae species, and their use to promote earlier and more abundant flowering in breeding orchards of grafted ramets for at least two species, loblolly pine and Douglas fir [Pseudotsuga menziesii (Mirb.) Franco] is practical.
Effect of Gibberellic Acid and Monophenols on Flowering of lmpatiens balsamina in Relation to the Number of Inductive and Non‐inductive Photoperiodic Cycles
Authors: SOOD VINI , NANDA K. K. 
Published: April 2006

AbstractA single treatment of plants with GA3 (gibberellic acid) is not adequate to cause induction under LD (long day: 24‐h photo‐period) condition, but its effect is added to the sub‐threshold induction caused by one SD (short day: 8‐h photoperiod) cycle. Floral bud initiation is hastened, and the number of floral buds and flowers per flowering plant increases in plants receiving a single treatment with the combination GA3+ SA (salicylic acid) accompanying a single SD cycle. However, the increase on 10 replicate basis is more marked in plants receiving three treatments with the combination GA3+β‐N (β‐naphthol) and five treatments with the combination GA3+ SA accompanying six and 10 SD cycles, respectively. The number of floral buds and flowers decreases with an increase hi the number of SD cycles, but it is higher in plants treated with GA3, SA or GA3+β‐N than in the water‐treated controls. — Under long days, treatment of plants with the combinations GA3+ SA or GA3+β‐N accelerates the initiation as well as increases the number of floral buds. While a minimum of five treatments with GA3 or of 25 with SA or β‐N alone is needed for floral bud initiation under a 24‐h photoperiod, three treatments are adequate to induce floral buds with the combination GA3+ SA or GA3+β‐N under continuous illumination. Ten or more treatments with these combinations under a 24‐h photoperiod produce more flowers than the same treatments under an 8‐h photoperiod.