bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lipid and Fatty Acid Composition of Tree‐Growing and Terrestrial Lichens
Authors: DERTIEN BART K. , DE KOK LUIT J. , KUIPER PIETER J. C. 
Published: April 2006

AbstractA comparison of lipid and fatty acid composition was made of the tree‐growing lichens Evernia prunastri (L.) Ach., Parmelia saxatilis (L.) Ach. and Hypogymnia physodes (L.) Ach. and the terrestrial species Cetraria islandica (L.) Ach. and Cladonia impexa Harm.In the terrestrial species the total lipid content varied strongly during spring, while the tree‐growing species showed much less variation. Phospholipid and sterol content of all lichens was unusually low. Monoglycosyl diglyceride was absent from Parmelia saxatilis. Fatty acids common to higher plants as palmitic, stearic, oleic, linoleic and linolenic acid were invariably present in all lichen species. In addition large quantities of extra‐long chain fatty acids like behenic acid, eicosadienoic acid and cyclic aliphatic lichen acids were present in the terrestrial species. The degree of (poly) unsaturation decreased in the order Evernia prunastri, Parmelia saxatilis. Fatty acids common to higher plants as palmitic, stearic, impexa, which decrease was compensated by an increase in extralong chain fatty acids and lichen acids. It is suggested that the lichen acids are of adaptive value for lichen species growing in the terrestrial habitats, which were characterized by extreme diurnal temperature variations. Just as the polyunsaturated fatty acids, lichen acids guarantee at lower temperatures a high flexibility of the membranes involved, at the same time as they are less susceptible to photo‐oxidation at the high daytime temperatures.
Wavelength Dependence in the Red and Far‐Red for Induction of Phytochrome Increase in Mung Bean Hooks
Authors: TANADA T. 
Published: April 2006

AbstractThe wavelength dependence for a radiation induced increase of phytochrome in mung bean hooks (Vigna radiata L.), preirradiated with red light, was determined between 640 to 800 nm. Radiation between 640 to 700 nm and 780 to 800 nm had little effect on phytochrome concentration in hooks pretreated with red. Two bands of far‐red light, one at 710 nm and the other at 750 to 760 nm, were found to increase phytochrome content about four times. Besides the requirement for a photochemical process, one or more dark processes appear to be necessary for the induction of phytochrome increase.
Leaf Water Potential and the Rooting of Cuttings under Mist and Polythene
Authors: LOACH K. 
Published: April 2006

AbstractThe relationship between leaf water potential and rooting was investigated in cuttings of Rhododendron (Hardy Hybrid) ‘Mrs. W. Agnew’, Ceanothus thyrsiflorus Esch. and Hebe (Garden Hybrid) ‘Caledonia’ (of the ‘Mrs. Winder’ group), during propagation under mist and polythene. Water potentials well below –10 bars frequently occurred and low mean water potentials related to poor rooting. Propagation under polythene gave better results than mist in the lower radiation conditions of winter but the reverse occurred under high radiation conditions. Treatment of cuttings with a poly‐vinyl resin antitranspirant coating temporarily increased leaf water potentials in the consistently humid conditions under polythene but not under mist. The coating peeled and lost its effectiveness within 6 weeks.Multiple regression analysis showed that much of the variation in water potential in cuttings under mist could be accounted for by inclusion of three variables, viz. current day's radiation, number of days from insertion of the cuttings and either the previous day's leaf water potential or radiation. Under polythene the influence of yesterday's water potential was relatively unimportant, probably because cuttings were able to take up water overnight from condensation on the under surface of the polythene.For optimal rooting, propagation procedure must ensure that high leaf water potentials are maintained, but conventional methods do not always achieve this.
The Effect of Phytohormones on Chlorophyll(ide), Protochlorophyll(ide) and Carotenoid Formation in Greening Dark Grown Wheat Leaves
Authors: BENGTSON CURT , KLOCKARE BIRGITTA , LARSSON STIG , SUNDQVIST CHRISTER 
Published: April 2006

AbstractThe influence of phytohormones on chlorophyll and carotenoid formation during the greening of irradiated dark grown wheat leaves (Triticum aestivum L. cv. Starke II Weibull) was studied. Leaves were floated on solutions of abscisic acid, gibberellic acid and kinetin for 24 h. The chlorophyll and carotenoid contents were determined during a subsequent period of 48 h of continuous irradiation. Leaves treated with abscisic acid showed a longer lag phase and a lower rate of accumulation of chlorophyll as compared to the control than did leaves treated with gibberellic acid and kinetin. The carotenoid content was low both in leaves treated with abscisic acid and in those treated with gibberellic acid. Treatment with abscisic acid lowered the protochlorophyllide regeneration after a saturating light flash while gibberellic acid as well as kinetin had no effect. The influence of ABA was partly dependent on an increase of the wounded part of the cut leaf segments. The accumulation of protochlorophyllide in leaves treated with δ‐aminolevulinic acid was not affected by the different hormonal treatments. These results suggest that the main effect of abscisic acid is probably outside the chloroplast, i.e. on the formation or transport of δ‐aminolevulinic acid.
Flavolans and Growth‐Promoting Catechins in Young Shoot Tips of Prunus Species and Hybrids
Authors: FEUCHT W. , NACHIT M. 
Published: April 2006

AbstractYoung shoot tips of species and hybrids from the Prunus section eucerasus contain catechin, epicatechin and flavolans (oligomeric flavans including biflavans). Prunus avium shoot segments, 2 mm in length, were excised from the elongating zone of growing shoots and cultured in vitro on a liquid Murashige and Skoog medium containing indolyl‐3‐acetic acid and benzyl adenine. Supplementation of the same medium with (+)‐catechin and epicatechin resulted in apparent promotion of callus growth. This effect was greater under long day conditions than under continuous dark.
Determination of Fatty Acid Composition of Spore Lipids of the Moss Polytrichum commune by Glass Capillary Column Gas Chromatography
Authors: KARUNEN P. 
Published: April 2006

AbstractFatty acid methyl esters of Polytrichum commune spore triglyceride and mono‐ and diglycosyl diglyceride fractions were analysed by glass capillary column gas chromatography provided with a precolumn system. The composition of the fatty acids in the lipid fractions differed only quantitatively: the diglycosyl diglyceride fraction was characterized by a high content of C 18: 3ω3 (67.7%), and the triglyceride and monoglycosyl diglyceride fractions by about 35%. The monoglycosyl diglyceride fraction contained a high proportion of C 14: 0 (18.4%). In all fractions the content of polyunsaturated C 20 acids was low, ranging from trace amounts to 4.9%.
The Importance of Cell Size in the Water Relations of Plants
Authors: CUTLER J. M. , RAINS D. W. , LOOMIS R. S. 
Published: April 2006

AbstractSeveral structural changes in cotton (Gossypium hirsutum L.) leaves attendant on development under conditions of water deficit were examined. Cell size was less and cell wall thickness greater in the leaves of stressed plants than in leaves of well‐watered plants. A short review of the literature suggested that the lesser cell size is a fairly general observation and that it may contribute to plant resistance to moisture stress.A simple model is developed to investigate the influence of the reduction of cell size on cellular water relations. The predictions which can be drawn from simulations with this model are that smaller cells should maintain turgor to lower values of water potential than larger cells. Rather large changes in cell water relations are predicted for small changes in cell size. These effects are related principally to the changing proportion of cell water which resides in the cell wall and is external to the plasmalemma and the osmotic adjustment system. This prediction is in agreement with several observerations on the behavior of stress‐hardened plants and supports the hypothesis that plants or tissues with the smaller cell size will be more tolerant of low water potential.
Rooting Substances in Water Extracts of Castanea sativa and Salix viminalis
Authors: GESTO M. D. V. , VÁZQUEZ A. , VIEITEZ E. 
Published: April 2006

AbstractThe rooting activity of water extracts of cuttings of chestnut (Castanea sativa Mill.) and willow (Salix viminalis L.) was studied throughout the year by the bean rooting test. The chestnut extract nullified the rooting activity of 10−5M IAA, but on the whole it did not modify the rooting pattern of the bean cuttings. The willow extract increased rooting and showed a rhythm in the content of endogenous growth substances. IAA was found at the time when the extract showed the strongest rooting activity. The extract from willow contained two synergistic root‐promoting fractions with the Rf's of 0.0–0.2 and 0.6–0.8 in isopropanol: ammonia: water. The latter one promoted rooting without added IAA. In this fraction a high amount of catechol was detected. No clear correlation was found between the ability to induce roots and the total phenol content in the two species.
Mise en Évidence d'un Effet Régulateur de la Proline Exogène sur le Cycle du Glycolate Chez Nicotiana tabacum cv. Xanthi
Authors: VALLEE J. C. , VANSUYT G. , PREVOST J. 
Published: April 2006

AbstractDemonstration of a regulatory effect of exogenous proline on the glycolate cycle in Nicotiana tabacum cv. Xanthi n.c.An exogenous proline supply in the light provokes an increase in free glycine concentration in apical tissues or leaf disks of vegetative Nicotiana tabacum cv. Xanthi n.c. The same phenomenon does not occur in the equivalent tissues of tobacco plants after floral induction, these being naturally rich in proline. Under different environmental conditions (light, dark, varying concentrations of CO2 and O2), the exogenous proline appears to modify one or more reactions of the glycolate pathway.
Change in Electrophoretic Pattern of Ribonuclease during Dormancy and Growth of Bird‐cherry Buds
Authors: EKELUND R. , PERSSON L. 
Published: April 2006

AbstractPolyacrylamide gel electrophoresis of ribonuclease from buds of bird‐cherry (Prunus padus L.) revealed four different bands (I–IV). The activity of band I, which probably corresponds to an in vivo free ribonuclease, increased from October to January — most rapidly between December, when 69% of the buds were dormant, and January when 43% were in the dormant state — but did not change from January to March, when growth was resumed. Bands II–IV may represent ribonucleases which are structure‐bound in vivo. The activity of band II decreased from October to a minimum in January and then increased from January to March. The activities of bands III and IV were very low from October to February but were enhanced with acceleration of growth in March. The results may indicate that the separate ribonucleases have different functions.
Ethylene Requirement for Germination of Partly After‐ripened Apple Embryo
Authors: KEPCZYNSKI JAN , RUDNICKI RYSZARD M. , KHAN ANWAR A. 
Published: April 2006

AbstractThe effect and involvement of ethylene in germination of partially after‐ripened apple (Malus domestica Borkh. cv. Antonovka) embryos were studied. The requirement of ethylene for germination was shown by the use of a rhizobitoxine analog and 8‐hydroxy‐quinoline sulphate which are inhibitors of ethylene biosynthesis, and by mercuric perchlorate, a trap for endogenously produced ethylene. Excised apple embryos were found to produce progressively greater amounts of ethylene with increasing periods of after‐ripening. Inhibition of germination by rhizobitoxine analog or abscisic acid was accompanied by inhibition of ethylene formation in embryos. Thus ethylene appears to be required for the release of dormancy and germination of apple embryos.
Seasonal Changes in the Cytokinin Content of the Leaves of Salix babylonica
Authors: VAN STADEN J. 
Published: April 2006

AbstractThe young and old leaves of Salix babylonica contain at least four cell division‐inducing compounds which coeluted with zeatin, zeatin riboside and their glucosylated derivatives. During the course of the growing season quantitative changes in the cytokinin content of the leaves were observed. The cytokinin glucosides increased as the leaves aged. The compounds which co‐chromatographed with zeatin and zeatin riboside initially increased until early autumn and then decreased as the leaves senesced. It appears as though the cytokinins transported from the roots are metabolized in the leaves and are converted to their glucosides. Although it has been reported in the literature that Salix root exudate contains very small amounts of cytokinin in late summer and autumn, these compounds increase in the leaves for most of the growing season, suggesting that the leaves may not only obtain cytokinins from the roots but may well be an active site of cytokinin synthesis. It is, however, possible that cytokinins are also transported to the leaves via the phloem, thus accounting for their accumulation in these organs.
Pretreatment of Cell Suspensions as a Method to Increase the Protoplast Yield of Haplopappus gracilis
Authors: WALLIN ANITA , GLIMELIUS KRISTINA , ERIKSSON TAGE 
Published: April 2006

AbstractA low yield of free protoplasts was obtained when fast‐growing cell suspensions of Haplopappus gracilis were treated with Driselase, an active mixture of cellulase and pectinase. If the cells in the suspension culture were pretreated by increased levels of auxin, reduced sugar concentration, addition of sulphur‐containing amino acids, or by the reducing agent mercaptoethanol, protoplasts were released from a higher proportion of the cells. These pretreatments did not adversely effect division of the protoplasts.
The Effects of Calcium and the Ionophore A23I87 on Modulation, Nitrogen Fixation and Growth of Soybeans
Authors: BLEVINS DALE G. , BARNETT NEAL M. , BOTTINO PAUL J. 
Published: April 2006

AbstractThe calcium ionophore A23187 was used to separate the processes of infection and nodule development from nitrogen fixation in soybeans. Seedlings of Glycine max (L.) Merr. cv. Williams were grown in solution cultures containing three concentrations of Ca2+ (0.1, 0.5 or 1.0 mM) with or without 0.5 μM ionophore A23187. Three weeks after inoculation with Rhizobium japonicum, strain B1. plants were harvested. Low Ca2+ (0.1 mM) significantly reduced nodule number and weight, acetylene reduction, fresh weight of roots and shoots and increased lengths of 2nd and 3rd internodes. There were no significant differences between 0.5 and 1.0 mM Ca2 in their influence on any parameters measured, except for Ca2+ concentration in the tissue. The ionophore A23187 significantly reduced nodule number and weight, and increased internode lengths, but it had no effect on acetylene reduction or fresh weight of roots and tops. The ionophore did not affect the Ca2+ concentration of roots, tops or nodules. Therefore, nitrogen fixation rate is partially independent of number and weight of nodules. The single most important result of this study is that the ionophore A23187 affected critical steps in the infection process or nodule development without influencing subsequent nitrogen fixation.
Effect of Galactose and Other Monosaccharides on IAA Movement in Bean Hypocotyl Segments
Authors: KRUL WILLIAM R. , COLCLASURE G. CRAIG 
Published: April 2006

AbstractGalactose enhances the production of ethylene gas, and ethylene gas inhibits the movement of IAA in plant tissues. If galactose enhances ethylene production and ethylene inhibits auxin movement, then galactose should inhibit auxin movement. The above hypothesis was examined by observing the effects of d‐galactose, d‐inannose, d‐arabinose, d‐glucose, and d xylose on the uptake, presumed decarboxylation, efflux, velocity and metabolism of labeled indole‐3‐aectic acid in hypocotyl segments of Phaseolus vulgaris L. cv. Pinto. Galactose inhibited, arabinose and glucose enhanced, and mannose and xylose had no effect on partitioning of auxin between tissue and receptor. The reduction of auxin efflux by galactose was related to an increased presumed decarboxylation, reduced uptake and slower velocity of applied auxin. The relationship between galactose‐induced growth effects, ethylene production, and auxin migration are discussed.
The Physiology of the Lichen Peltigera aphthosa, with Special Reference to the Blue‐green Phycobiont (Nostoc sp.)
Authors: ENGLUND BIRGITTA 
Published: April 2006

AbstractVariations in the morphology and physiology were noted when parts of the Peltigera aphthosa Willd. thallus differing in age were examined. The many small cephalodia on the growing apex of the lichen showed a lower heterocyst frequency (14%) than those on the rest of the thallus (21–22%), which was reflected in the nitrogenase activity. In contrast, highest levels of photosynthesis (14CO2 uptake and O2 evolution) were noted at the growing apex. while respiration rates were fairly stable over the thallus. The water‐holding capacity was greatest in the midparts.Cephalodial biomass represented an average of 2.6% of total thallus biomass. while the number and size of these structures varied considerably. A minor part of the total carbon fixation (14CO2) and net oxygen evolution (O2 electrode) was performed by the blue‐green phycobiont (Nostoc) in light. A rapid excretion of ammonia from isolated cephalodia was noticed, which together with a comparatively constant C:N ratio throughout the thallus indicated a rapid transport of metabolites facilitated by close physical contact (electron microscopy).
Potassium Absorption by Rice at Different Levels of Organization
Authors: ERDEI LÁSZLÓ , TÓTH ILDIKÓ , ZSOLDOS FERENC 
Published: April 2006

AbstractThe effects of Ca2+ and K+ on the ATPase activities of microsomal fractions prepared from mature roots, cell suspension and callus cultures and redifferentiated roots of rice (Oryza sativa L. cv. Dunghan Shali) exhibit correlations with the effects of Ca2+ on the K+ influx rates. ATPase stimulated by Ca2+ and K+ and the stimulatory effect of Ca2+ on K+ influx are associated in mature roots of low‐salt status. Roots of high‐salt status also possess ATPase of this kind, but K+ influx is depressed by Ca2+. Cell suspension and callus tissue cultures do not possess K+ influx with a positive Ca2+‐response and the ATPase prepared from them is insensitive to the effects of Ca2+ and K+. Redifferentiated roots show similar transport characteristics and enzyme pattern as mature roots of high salt status. The specific transport function of the membrane, and the ATPase stimulated by Ca2+ and K+ are suggested to develop during diffrentiation.
Photosynthetic Capacities and Growth Characteristics of Nicotiana tabacum (cv. Xanthi) Cell Suspension Cultures
Authors: NATO A. , BAZETOUX S. , MATHIEU Y. 
Published: April 2006

AbstractPhotoheterotrophic growth of cell suspensions of Nicotiana tabacum L. (cv. Xanthi) in organic culture medium enriched in sucrose (30 g per liter) showed a classical sigmoid growth curve. The cells developed functional chloroplast structures during the exponential growth phase, when their chlorophyll content increased steadily. A limited drop (30%) in the chlorophyll amount and structural changes of the plastids (starch accumulation) were observed during the lag phase. The measurements of photosynthetic capacities (O2 evolution and CO2 fixation) during the growth cycle revealed changes in the photosynthetic ratio (O2/CO2), which was near 1 during the lag and stationary phases and near 2 during exponential growth. During exponential growth there was also a rapid NO3− uptake. Analysis of label distribution among the products of 14CO2 fixation showed that both CO2 assimilation pathways, linked to the ribulose‐biphosphate carboxylase (the autotrophic pathway) and to phosphoenolpyruvate carboxylase (the non‐autotrophic pathway) were operative with an important increase of the capacity of the latter during the exponential growth phase. Maximum rate of oxygen evolution, either endogenous or with p‐benzoquinone as Hill reagent, as well as the increased CO2 Fixation capacity via the non‐autotrophic pathway during the exponential phase were concomitant with a high cyanide inhibited O2 uptake.
In vitro Organogenesis in Explants from Different Cultivars of Begonia X hiemalis
Authors: WELANDER TORKEL 
Published: April 2006

AbstractPetiole explants from 17 cultivars of Begonia X hiemalis were grown on a basal agar medium with different combinations of NAA and BA as well as on media lacking microelements or vitamins. The stock plants were kept either under short days (7–8 h of light perday) at 15°C or under long days (15–16 h of light) at 18–21°C. The day length during the in vitro culture was 20 h of light and the temperature 21°C.Explants from short‐day treated stock plants did not show any differentiation. In explants from long‐day treated stock plants, the percentage of explants with shoot, root and with both shoot and root initiation were recorded after 55 days. Explants forming both shoots and roots were transferred to soil, and plantlet formation was observed after another 55 days. The percentage of explants with organ and plantlet formation differed between cultivars. With increasing NAA and decreasing BA concentrations, the percentage of explants forming only roots increased, whereas the percentage of explants with only shoots decreased. Plantlet formation was most frequent in explants from NAA: BA ratios of 2: 1 and 10: 1, and a variation was found between different cultivars. When the vitamin fraction was not added to the medium, this did not influence formation of shoots, roots and plantlets. When the microelements were omitted. shoots, roots and callus were formed, but no plantlets.
Blue Light‐Induced Phytochrome Increase in Mung Bean Hooks
Authors: TANADA T. 
Published: April 2006

AbstractAn “action spectrum” between 400 and 620 nm for the radiation‐induced phytochrome increase was obtained with mung bean hooks. A broad band between 410 and 480 nm was found to induce significant increases in phytochrome content. Radiation from 500 to 620 nm failed to promote any significant increase. Red irradiation immediately following far‐red treatment showed no reversal. These results and an earlier finding that far‐red irradiation promotes phytochrome increase suggest that the photoreceptor for the radiation‐induced increase is probably not phytochrome, but could be a related pigment if the phenomenon is due to one photoreceptor. The blue light‐induced increase in phytochrome content increases the possibility of the participation of phytochrome in blue light‐mediated high irradiance responses of plants.