| organization of lipid reserves in cotyledons of primed and aged sunflower seeds. | imbibing sunflower (helianthus annuus l., cv. briosol) seeds at water potentials between -2 mpa and -5 mpa leads to faster (priming) or slower (accelerated ageing) germination depending on the temperature and duration of treatment. mobilization of food reserves may be associated with the changes in seed vigor. to study this, morphological, biochemical and phase properties of lipid, the major food reserve in sunflower, were compared in freshly harvested (i.e., control), primed and aged sunflower ... | 2005 | 16136327 |
| real-time polymerase chain reaction based assays for quantitative detection of barley, rice, sunflower, and wheat. | quality assurance is a major issue in the food industry. the authenticity of food ingredients and their traceability are required by consumers and authorities. plant species such as barley (hordeum vulgare), rice (oryza sativa), sunflower (helianthus annuus), and wheat (triticum aestivum) are very common among the ingredients of many processed food products; therefore the development of specific assays for their specific detection and quantification are needed. furthermore, the production and tr ... | 2005 | 16131102 |
| enhanced phytoextraction: ii. effect of edta and citric acid on heavy metal uptake by helianthus annuus from a calcareous soil. | high biomass producing plant species, such as helianthus annuus, have potential for removing large amounts of trace metals by harvesting the aboveground biomass if sufficient metal concentrations in their biomass can be achieved however, the low bioavailability of heavy metals in soils and the limited translocation of heavy metals to the shoots by most high biomass producing plant species limit the efficiency of the phytoextraction process. amendment of a contaminated soil with ethylene diamine ... | 2005 | 16128445 |
| enhanced phytoextraction: i. effect of edta and citric acid on heavy metal mobility in a calcareous soil. | phytoextraction, the use of plants to extract heavy metals from contaminated soils, could be an interesting alternative to conventional remediation technologies. however, calcareous soils with relatively high total metal contents are difficult to phytoremediate due to low soluble metal concentrations. soil amendments such as ethylene diaminetetraacetate (edta) have been suggested to increase heavy metal bioavailability and uptake in aboveground plant parts. strong persistence of edta and risks o ... | 2005 | 16128444 |
| lateral diffusion of co2 in leaves is not sufficient to support photosynthesis. | lateral diffusion of co(2) was investigated in photosynthesizing leaves with different anatomy by gas exchange and chlorophyll a fluorescence imaging using grease to block stomata. when one-half of the leaf surface of the heterobaric species helianthus annuus was covered by 4-mm-diameter patches of grease, the response of net co(2) assimilation rate (a) to intercellular co(2) concentration (c(i)) indicated that higher ambient co(2) concentrations (c(a)) caused only limited lateral diffusion into ... | 2005 | 16113223 |
| a bioactive annuionone from sunflower leaves. | from aqueous extract of helianthus annuus l. cv. suncross-42 leaves, a annuionone have been isolated. the structural elucidation of the compound is based on 1h and 13c nmr spectral studies. the potential of the compound to be used as natural herbicide template has been evaluated through laboratory bioassays against five weed species. results proved annuionone h as a potent plant growth inhibitor that can be exploit for the development of a herbicide model. | 2005 | 16112694 |
| formation and stability of foams made with sunflower (helianthus annuus) proteins. | foam properties of a sunflower isolate (si), as well as those of helianthinin and sunflower albumins (sfas), were studied at various ph values and ionic strengths and after heat treatment. less foam could be formed from helianthinin than from sfas, but foam prepared with helianthinin was more stable against ostwald ripening and drainage than foam prepared with sfas. foams made with sfas suffered from extensive coalescence. the formation and stability of foams made from reconstituted mixtures of ... | 2005 | 16076136 |
| improving alpha-tocopherol production in plant cell cultures. | suspension cell cultures of helianthus annuus l. were previously established for the production of the most active component of vitamin e, alpha-tocopherol, by optimizing medium composition and culture conditions. in the present work, the possibility of enhancing alpha-tocopherol production by the addition of jasmonic acid to the culture medium was investigated both in sunflower and arabidopsis cell cultures. a considerable increase (49% and 66%, respectively) of alpha-tocopherol production was ... | 2005 | 16008104 |
| hybridization and genome size evolution: timing and magnitude of nuclear dna content increases in helianthus homoploid hybrid species. | hybridization and polyploidy can induce rapid genomic changes, including the gain or loss of dna, but the magnitude and timing of such changes are not well understood. the homoploid hybrid system in helianthus (three hybrid-derived species and their two parents) provides an opportunity to examine the link between hybridization and genome size changes in a replicated fashion. flow cytometry was used to estimate the nuclear dna content in multiple populations of three homoploid hybrid helianthus s ... | 2005 | 15998412 |
| oils from improved high stearic acid sunflower seeds. | seed oils from new recombinant high-stearic sunflower lines (helianthus annuus l.) have been characterized. these new lines were generated by crossing high stearic acid lines between themselves or by crossing them with standard and high-oleic sunflower lines. of the novel lines generated, the lines cas-29 and cas-30 are on a standard background and contain up to 34.5% of stearic acid. in contrast, cas-15 and cas-33 are on a high oleic acid background and contain only 24.9 and 17.4% of stearic ac ... | 2005 | 15969513 |
| re-creating ancient hybrid species' complex phenotypes from early-generation synthetic hybrids: three examples using wild sunflowers. | can the complex phenotypes that characterize naturally occurring hybrid species be re-created in early-generation artificial hybrids? we address this question with three homoploid hybrid species (helianthus anomalus, helianthus deserticola, helianthus paradoxus) and their ancestral parents (helianthus annuus, helianthus petiolaris) that are phenotypically distinct and ecologically differentiated. these species, and two synthetic hybrid populations of the ancestral parents, were characterized for ... | 2005 | 15937787 |
| cdna cloning and expression of the phytoene synthase gene in sunflower. | a pcr approach was used to isolate a phytoene synthase (psy) cdna from sunflower (helianthus annuus l.). a reconstructed full-length sequence (1598 bp) of the psy cdna was obtained; it contained a 1242 bp cds, 172-nucleotides of 5'-untranslated region (utr), and 170-nucleotides of 3'-utr. the predicted protein (46.8kda) displayed a sequence of 414 amino acid residues with a putative transit sequence for plastid targeting in the n-terminal region. phylogenetic analysis demonstrated that the sunfl ... | 2005 | 15900891 |
| short-period circumnutations found in sunflower hypocotyls in satellite orbit. a reappraisal of data from spacelab-1. | we have further analysed data from an experiment performed in satellite orbit, in spacelab-1. in micro-gravity the hypocotyls of helianthus annuus, cv. "teddy bear", showed short period circumnutations (periods around 30 minutes) as well as the already reported long period nutations (with an average period of about 115 minutes). we applied various types of signal analysis (fourier and wavelet analysis) to the data series. the long period circumnutations have a larger amplitude than the short ter ... | 2003 | 15838960 |
| cytological development and sesquiterpene lactone secretion in capitate glandular trichomes of sunflower. | the secretion of sesquiterpene lactones (stl) in capitate glandular trichomes from the anther appendages of helianthus annuus l. (asteraceae) was observed by light and fluorescence microscopy and hplc analysis. disk flowers within the sunflower capitulum showed the known ontogenetic progression from the centre to the margin. during development of the florets, the trichomes in the anther appendages secreted their metabolites into the subcuticular secretion storage space in front of the two apical ... | 2005 | 15822010 |
| a fragment of chloroplast dna was transferred horizontally, probably from non-eudicots, to mitochondrial genome of phaseolus. | the mitochondrial genomes of some phaseolus species contain a fragment of chloroplast trna gene intron, named pvs-trna for its location within the phaseolus vulgaris sterility sequence (pvs). the purpose of this study was to determine the type of transfer (intracellular or horizontal) that gave rise to pvs-trna. using a pcr approach we could not find the respective portion of the trna gene as a part of pvs outside the phaseolus genus. however, a blast search revealed longer fragments of trna pre ... | 2004 | 15803417 |
| [the effect of oxidative stress on nitrosomethylurea-induced mutagenesis in sunflower helianthus annuus l]. | the effect of hyberbaric oxygenation on mutagenicity of nitrosomethylurea (nmu) was examined. it was shown that in the regimes studied, hyperbaric oxygenation enhances the nmu mutagenic effect both on the nuclear and on the plastid genetic material of sunflower, but do not increase intensity of free-radical reactions and do not induce plastid mutations and chromosome aberrations per se. at high concentrations inducing chromosome aberrations (0.03%), nmu was shown to enhance the level of free-rad ... | 2005 | 15771252 |
| emulsion properties of sunflower (helianthus annuus) proteins. | emulsions were made with sunflower protein isolate (si), helianthinin, and sunflower albumins (sfas). emulsion formation and stabilization were studied as a function of ph and ionic strength and after heat treatment of the proteins. the emulsions were characterized with respect to average droplet size, surface excess, and the occurrence of coalescence and/or droplet aggregation. sunflower proteins were shown to form stable emulsions, with the exception of sfas at neutral and alkaline ph values. ... | 2005 | 15769166 |
| the sources of carbon and reducing power for fatty acid synthesis in the heterotrophic plastids of developing sunflower (helianthus annuus l.) embryos. | the provision of carbon substrates and reducing power for fatty acid synthesis in the heterotrophic plastids of developing embryos of sunflower (helianthus annuus l.) has been investigated. profiles of oil and storage protein accumulation were determined and embryos at 17 and 24 days after anthesis (daa) were selected to represent early and late periods of oil accumulation. plastids isolated from either 17 or 24 daa embryos did not incorporate label from [1-(14)c]glucose 6-phosphate (glc6p) into ... | 2005 | 15767323 |
| chloroplast ssr polymorphisms in the compositae and the mode of organellar inheritance in helianthus annuus. | because organellar genomes are often uniparentally inherited, chloroplast (cp) and mitochondrial (mt) dna polymorphisms have become the markers of choice for investigating evolutionary issues such as sex-biased dispersal and the directionality of introgression. to the extent that organellar inheritance is strictly maternal, it has also been suggested that the insertion of transgenes into either the chloroplast or mitochondrial genomes would reduce the likelihood of gene escape via pollen flow fr ... | 2005 | 15690173 |
| the effect of edta on helianthus annuus uptake, selectivity, and translocation of heavy metals when grown in ohio, new mexico and colombia soils. | the use of two edta concentrations for enhancing the bioavailability of cadmium, chromium, and nickel in three natural soils (ohio, new mexico and colombia) was investigated. the resulting uptake, translocation and selectivity with helianthus annuus after mobilization were also examined. in general, plants grown in the sandy-loam ohio soil had a higher uptake that resulted in a selectivity and total metal content of cd>cr>ni and 0.73 mg and cr>cd>ni and 0.32 mg for 0.1 and 0.3 g kg-1 edta, respe ... | 2005 | 15664616 |
| comparison of edta and edds as potential soil amendments for enhanced phytoextraction of heavy metals. | phytoextraction has been proposed as an alternative remediation technology for soils polluted with heavy metals or radionuclides, but is generally conceived as too slow working. enhancing the accumulation of trace pollutants in harvestable plant tissues is a prerequisite for the technology to be practically applicable. the chelating aminopolycarboxylic acid, ethylene diamine tetraacetate (edta), has been found to enhance shoot accumulation of heavy metals. however, the use of edta in phytoextrac ... | 2005 | 15664609 |
| seawater irrigation: antioxidant defence responses in leaves and roots of a sunflower (helianthus annuus l.) ecotype. | salinity is a widespread environmental stress for crop plants. it is common in arid, semiarid, and coast regions. in those environments, seawater infiltrations can occur or the sea provides the only source of water for irrigation. the effects of 10% and 20% seawater in nutrient solutions were studied in 30 day-old plants of sunflower (helianthus annuus l.) ecotype katharina piacenza. growth parameters, ascorbate and glutathione contents, and the activities of ascorbate peroxidase and glutathione ... | 2004 | 15658806 |
| [polymorphism and inheritance of seed storage protein in sunflower]. | the data on polymorphism and inheritance of the seed storage protein helianthinin are presented. the results of hybrid analysis indicate that in the annual sunflower helianthus annuus, helianthinin synthesis is controlled by at least three loci: hela, helb, helb, and helc. codominant alleles controlling different electrophoretic variants of polypeptides were identified at each of the loci. the hela locus was inherited independently of helb and helc in a series of dihybrid crosses. the frequencie ... | 2004 | 15559149 |
| genetics of species differences in the wild annual sunflowers, helianthus annuus and h. petiolaris. | much of our knowledge of speciation genetics stems from quantitative trait locus (qtl) studies. however, interpretations of the size and distribution of qtl underlying species differences are complicated by differences in the way qtl magnitudes are estimated. also, many studies fail to exploit information about qtl directions or to compare inter- and intraspecific qtl variation. here, we comprehensively analyze an extensive qtl data set for an interspecific backcross between two wild annual sunf ... | 2005 | 15545657 |
| sunflower trypsin inhibitor-1. | sfti-1 is a bicyclic 14 amino acid peptide that was originally isolated from the seeds of the sunflower helianthus annuus. it is a potent inhibitor of trypsin, with a sub-nanomolar k(i) value and is homologous to the active site region of the well-known family of serine protease inhibitors known as the bowman-birk trypsin inhibitors. it has a cyclic backbone that is cross-braced by a single disulfide bridge and a network of hydrogen bonds that result in a well-defined structure. sfti-1 is amenab ... | 2004 | 15544530 |
| lipoxygenase-mediated metabolism of storage lipids in germinating sunflower cotyledons and beta-oxidation of (9z,11e,13s)-13-hydroxy-octadeca-9,11-dienoic acid by the cotyledonary glyoxysomes. | during the early stages of germination, a lipid-body lipoxygenase is expressed in the cotyledons of sunflowers (helianthus annuus l.). in order to obtain evidence for the in vivo activity of this enzyme during germination, we analyzed the lipoxygenase-dependent metabolism of polyunsaturated fatty acids esterified in the storage lipids. for this purpose, lipid bodies were isolated from etiolated sunflower cotyledons at different stages of germination, and the storage triacylglycerols were analyze ... | 2005 | 15526214 |
| conformational states of sunflower (helianthus annuus) helianthinin: effect of heat and ph. | the structure and solubility of helianthinin, the most abundant protein of sunflower seeds, was investigated as a function of ph and temperature. dissociation of the 11s form (hexamer) into the 7s form (trimer) gradually increased with increasing ph from 5.8 to 9.0. high ionic strength (i = 250 mm) stabilizes the 11s form at ph > 7.0. heating and low ph resulted in dissociation into the monomeric constituents (2-3s). next, the 7s and 11s forms of helianthinin were isolated and shown to differ in ... | 2004 | 15506815 |
| bioactive lignans from a cultivar of helianthus annuus. | a bioassay-guided fractionation of water extracts from helianthus annuus cv. sh-222 was carried out. ten lignans and a phenylpropanoid were isolated from the polar bioactive fractions of h. annuus. this study is the first to report lignans as constituents of sunflower and is the first time that tanegool has been isolated as a natural aglycone. additionally, we report biological activities of the isolated compounds. the general bioactivity has been evaluated using the wheat coleoptiles bioassay. ... | 2004 | 15479004 |
| apparent respiratory discrimination is correlated with growth rate in the shoot apex of sunflower (helianthus annuus). | the literature offers no consensus as to whether the delta(13)c of respired co(2) is identical to that of the respiratory substrate, perhaps because of differences in measurement technique and growth conditions. to address this issue, the delta(13)c of respired co(2) from growing sunflower shoot apices was measured and compared with that of soluble carbohydrates extracted from the respiring tissues. shoot apices were studied because any influence of growth and biosynthesis was expected to be max ... | 2004 | 15448174 |
| effect of ph and ionic strength modifications on thermal denaturation of the 11s globulin of sunflower (helianthus annuus). | helianthinin, the main storage protein of sunflowers, has low water solubility and does not form a gel when heated; this behavior is different from other 11s globulins and limits its food applications. to understand this particular behavior, changes on helianthinin association-dissociation state induced by modifications in ph and ionic strength were analyzed. the influence of these different medium conditions on its thermal stability and tendency to form aggregates was also studied. helianthinin ... | 2004 | 15366858 |
| decrement and amplification of slow wave potentials during their propagation in helianthus annuus l. shoots. | slow wave potentials (swps) are transitory depolarizations occurring in response to treatments that result in a pressure increase in the xylem conduits (p(x)). here swps are induced by excision of the root under water in 40- to 50-cm-tall light-grown sunflower plants in order to determine the effective signal range to a naturally sized pressure signal. the induced slow wave depolarization appears to move up the stem while it is progressively decremented (i.e. the amplitude decreases with increas ... | 2005 | 15365838 |
| genotypic variation and identification of qtls for agronomic traits, using aflp and ssr markers in rils of sunflower (helianthus annuus l.). | a population of 77 recombinant inbred lines (rils) were developed through single-seed descent from a cross between 'pac-2' and 'rha-266'. seeds of the above-mentioned rils and their parents were planted in the field in a randomised complete block design with two replications. genetic control for some agronomical traits-sowing-to-flowering date, plant height, stem diameter (sd), head diameter (hd), grain weight per plant, 1,000-grain weight (tgw) and the percentage of oil in grains-were measured ... | 2004 | 15365625 |
| the fly ash influenced the heavy metal status of the soil and the seeds of sunflower. a case study. | in this study, four cultivars of sunflower (helianthus annuus) were grown in the sandy loam soil, supplemented with graded (v/v) quantity (0, 20, 40, 60, 80, 100%) of the fly ash, released by the combustion of the coal from the thermal power plant. the presence of fly ash in the soil increased its porosity, water holding capacity, ph, e.c., c.e.c., the content of sulphate, carbonate, bicarbonate, chloride, phosphorus, potassium, calcium and various trace elements. however, in the seeds, except f ... | 2004 | 15303705 |
| reconstructing the origin of helianthus deserticola: survival and selection on the desert floor. | the diploid hybrid species helianthus deserticola inhabits the desert floor, an extreme environment relative to its parental species helianthus annuus and helianthus petiolaris. adaptation to the desert floor may have occurred via selection acting on transgressive, or extreme, traits in early hybrids between the parental species. we explored this possibility through a field experiment in the hybrid species' native habitat using h. deserticola, h. annuus, h. petiolaris, and two populations of ear ... | 2004 | 15278840 |
| light and metabolic regulation of has1, has1.1 and has2, three asparagine synthetase genes in helianthus annuus. | the role of light, carbon and nitrogen availability on the regulation of three asparagine synthetase (as, ec 6.3.5.4)-coding genes, has1, has1.1 and has2, has been investigated in sunflower (helianthus annuus). the response of each gene to different illumination conditions and to treatments that modify the carbon and nitrogen status of the plant was evaluated by northern analysis with gene-specific probes. light represses the expression of has1 and has1.1. phytochrome and photosynthesis-derived ... | 2004 | 15246064 |
| the effect of edta and citric acid on phytoremediation of cd, cr, and ni from soil using helianthus annuus. | the possibility to clean heavy metal contaminated soils with hyperaccumulator plants has shown great potential. one of the most recently studied species used in phytoremediation applications are sunflowers. in this study, two cultivars of helianthus annuus were used in conjunction with ethylene diamine tetracetic acid (edta) and citric acid (ca) as chelators. two different concentrations of the chelators were studied for enhancing the uptake and translocation of cd, cr, and ni from a silty-clay ... | 2004 | 15210283 |
| biochemical characterization of a high-palmitoleic acid helianthus annuus mutant. | in the present work we carried out analytical and biochemical studies on a new high-n-7 monounsaturated fatty acid sunflower (helianthus annuus l.) mutant. this new line, which has been selected by classical methods of breeding and mutagenesis, shows contents of unusual acyl chains up to 20% (12% of 16:1delta9, 5% of 16:2delta9,12 and 6% of 18:1delta11), whereas those fatty acids are found in negligible amounts in common sunflower cultivars. this characterization involved in vivo incubations wit ... | 2004 | 15191739 |
| hydraulic architecture of plants of helianthus annuus l. cv. margot: evidence for plant segmentation in herbs. | the hydraulic architecture of sunflower (helianthus annuus l. cv. margot) was studied in terms of the partitioning of the hydraulic conductance (kleaf) of leaves inserted at progressively more apical nodes both in growing plants (gp) and in plants at full anthesis (mature plants, mp). leaf conductance to water vapour (gl), leaf water potential (psil), leaf water potential at zero turgor (psi tlp), and leaf osmotic potential at full turgor (pi0) were also measured. sunflower plants showed gl and ... | 2004 | 15181104 |
| a deficiency at the gene coding for zeta-carotene desaturase characterizes the sunflower non dormant-1 mutant. | the non dormant-1 (nd-1) mutant of sunflower (helianthus annuus l.) is characterized by an albino and viviparous phenotype. pigment analysis by spectrophotometer and hplc demonstrated in nd-1 cotyledons the absence of beta-carotene, lutein and violaxanthin. additionally, we found a strong accumulation of zeta-carotene and, to a lesser extent, of phytofluene and cis-phytoene in nd-1 seedlings grown in very dim light (1 micro mol m(-2) s(-1)). these results suggested that zeta-carotene desaturatio ... | 2004 | 15111719 |
| [spontaneous and induced nitrosomethylurea reversion of plastomic chlorophyll mutants of the sunflower helianthus annuus l]. | spontaneous and induced revertants obtained from plastome chlorophyll mutants of sunflower were subjected to genetic analysis. the mechanism of reversion (nuclear suppression, plastid suppression, true reversion, or mitochondrial suppression) of the plastid mutation was shown to affect the degree of restoration of morphological and physiological traits of sunflower plants. | 2004 | 15065433 |
| purification of an ace inhibitory peptide after hydrolysis of sunflower (helianthus annuus l.) protein isolates. | sunflower protein isolates and the proteases pepsin and pancreatin were used for the production of protein hydrolysates that inhibit angiotensin-i converting enzyme (ace). hydrolysates obtained after 3 h of incubation with pepsin and 3 h with pancreatin were studied. an ace inhibitory peptide with the sequence phe-val-asn-pro-gln-ala-gly-ser was obtained by g-50 gel filtration chromatography and high-performance liquid chromatography c18 reverse phase chromatography. this peptide corresponds to ... | 2004 | 15053531 |
| identification of a novel gene, haabrc5, from helianthus annuus (asteraceae) that is upregulated in response to drought, salinity, and abscisic acid. | using differential display of mrna transcripts, we obtained a partial cdna clone, rsc5-u, that is upregulated by exposure to high salinity. a longer cdna of 812 nucleotides, designated haabrc5, was then cloned by rapid amplification of cdna ends. this full-length cdna contains an open reading frame of 423 nucleotides encoding 141 amino acids, including a "bipartite nuclear targeting sequence." the deduced amino acid sequence had no similarity to known genes in the database. the expression of haa ... | 2004 | 21653374 |
| phytotransformation of benzotriazoles. | plant roots interact with organic pollutants and some of these contaminants can be phytotransformed. root uptake of 1-h-benzotriazole and its derivatives, tolyltriazole, 5-methyl benzotriazole, and 1-hydroxy benzotriazole was studied. at levels below the toxic threshold of about 100 mg/l, triazoles appear to be incorporated into plant tissue. their concentration in the aqueous phase of the culture decreases with time and they cannot be extracted from the plant material using methanol. hydroponic ... | 2003 | 14750432 |
| candidate gene polymorphisms associated with salt tolerance in wild sunflower hybrids: implications for the origin of helianthus paradoxus, a diploid hybrid species. | we have studied the origin of salt adaptation in wild sunflower hybrids (helianthus annuus x h. petiolaris), the precursors of the diploid hybrid species h. paradoxus, at the level of phenotypic traits and quantitative trait loci (qtls). here, we review this work and present new results on candidate gene polymorphisms.salt tolerance candidate genes were identified in expressed sequence tag (est) libraries of sunflower, based on homology to genes with known function, and on previous qtl results. ... | 2004 | 19079642 |
| the rate of co(2) assimilation controls the expression and activity of glutamine synthetase through sugar formation in sunflower (helianthus annuus l) leaves. | the expression and activity of glutamine synthetase (gs, ec 6.3.1.2) were examined in relation to the rate of co2 assimilation in sunflower (helianthus annuus l.) leaves. intact plants were kept in the dark for 72 h and subsequently exposed to light under different atmospheric co2 concentrations (100, 400 and 1200 microl l-1) for 6 h. the in vivo rates of net co2 assimilation correlated with atmospheric co2 concentrations. stomatal conductances and transpiration rates remained largely unaffected ... | 2004 | 14645390 |
| effects of boron foliar applications on vegetative and reproductive growth of sunflower. | foliar application may be used to supply boron (b) to a crop when b demands are higher than can be supplied via the soil. while b foliar sprays have been used to correct b deficiency in sunflower (helianthus annuus l.) in the field, no studies have determined the amount of b taken up by sunflower plant parts via foliar application. a study was conducted in which sunflower plants were grown at constant b concentration in nutrient solution with adequate b (46 micro m) or with limited b supply (0.2 ... | 2003 | 12933368 |
| physical behavior of purified and crude wax obtained from sunflower (helianthus annuus) seed oil refineries and seed hulls. | the sunflower seed waxes obtained from two sources (i) seed hull as a standard and (ii) crude wax from oil refineries were studied for their crystallization, melting characteristics and morphology of crystals. the results of differential scanning calorimetry of wax obtained from seed hulls showed the melting temperature range of 13.18 degrees c with the onset at 62.32 degrees c, for purified wax, compared to the melting range of 24.73 degrees c with the onset at 42.3 degrees c. for crude wax. th ... | 2003 | 12906355 |
| vessel contents of leaves after excision: a test of the scholander assumption. | when petioles of transpiring leaves are cut in the air, according to the 'scholander assumption', the vessels cut open should fill with air as the water is drained away by tissue rehydration and/or continued transpiration. the distribution of air-filled vessels versus distance from the cut surface should match the distribution of lengths of 'open vessels', i.e. vessels cut open when the leaf is excised. a paint perfusion method was used to estimate the length distribution of open vessels and thi ... | 2003 | 12885866 |
| nitrate does not result in iron inactivation in the apoplast of sunflower leaves. | it has been hypothesized that nitrate (no(3)(-)) nutrition might induce iron (fe) deficiency chlorosis by inactivation of fe in the leaf apoplast (h.u. kosegarten, b. hoffmann, k. mengel [1999] plant physiol 121: 1069-1079). to test this hypothesis, sunflower (helianthus annuus l. cv farnkasol) plants were grown in nutrient solutions supplied with various nitrogen (n) forms (no(3)(-), nh(4)(+) and nh(4)no(3)), with or without ph control by using ph buffers [2-(n-morpholino)ethanesulfonic acid or ... | 2003 | 12857812 |
| impact of planting date on sunflower beetle (coleoptera: chrysomelidae) infestation, damage, and parasitism in cultivated sunflower. | the sunflower beetle, zygogramma exclamationis (f.), is the major defoliating pest of sunflower (helianthus annuus l.). planting date was evaluated as a potential management tool in a variety of production regions throughout north dakota from 1997 to 1999, for its impact on sunflower beetle population density of both adults and larvae, defoliation caused by both feeding stages, seed yield, oil content, and larval parasitism in cultivated sunflower. results from this 3-yr study revealed that sunf ... | 2003 | 12852608 |
| digestion of maize and sunflower pollen by the spotted maize beetle astylus atromaculatus (melyridae): is there a role for osmotic shock? | we investigated the mechanism and efficiency of digestion of two types of pollen, maize, zea mays, and sunflower, helianthus annuus, by the spotted maize beetle, astylus atromaculatus (melyridae). we found similar and high extraction efficiencies, but different mechanisms of digestion. osmotic shock was apparently involved in digestion of the large and thin-walled maize pollen grains. in the anterior midgut most maize pollen grains were already ruptured, in contrast with the intact exines of sun ... | 2003 | 12837316 |
| pcr-multiplexes for a genome-wide framework of simple sequence repeat marker loci in cultivated sunflower. | simple sequence repeat (ssr) and other dna sequence-tagged site markers can be genotyped more rapidly and cost efficiently by simultaneously amplifying multiple loci (multiplex pcr). the development of pcr-multiplexes for a nearly genome-wide framework of 78 ssr marker loci in cultivated sunflower ( helianthus annuus l.) is described herein. the most outstanding single-locus ssr markers in the public collection (300 out of 1,089) were identified and screened for polymorphisms among 24 elite inbr ... | 2003 | 12835928 |
| origin and development in vitro of shoot buds and somatic embryos from intact roots of helianthus annuus x h. tuberosus. | a variant clone of the tetraploid (2n = 4x = 68) interspecific hybrid helianthus annuus x h. tuberosus derived by in vitro tissue culture showed a deviation from the usual pattern of organization of the plant body. this variant developed shoot-like structures and somatic embryos from intact adventitious roots of in vitro-grown plantlets. the morphogenetic structures were not normally able to differentiate complete plants. they did show cellular proliferation with the inception of additional seco ... | 2003 | 12824073 |
| missing flowers gene controls axillary meristems initiation in sunflower. | the initiation and growth of axillary meristems are fundamental components of plant architecture. here, we describe the mutant missing flowers (mf) of helianthus annuus characterized by the lack of axillary shoots. decapitation experiments and histological analysis indicate that this phenotype is the result of a defect in axillary meristem initiation. in addition to shoot branching, mutation affects floral differentiation. the indeterminate inflorescence of sunflower (capitulum) is formed of a l ... | 2003 | 12748964 |
| recovery of non-target plants affected by airborne herbicides. | this study was conducted to determine the effects of airborne herbicides on the photosynthesis of non-target plants and to interpret and evaluate the observed effects airborne herbicides have on non-target plants. the study involved the exposition of sunflower (helianthus annuus l.) at different growth stages for 24 h in a wind tunnel to a range of various concentrations (0.012 to 4.104 micrograms/m3) of the herbicide bromoxynil, an inhibitor of photosynthesis. by means of chlorophyll fluorescen ... | 2002 | 12696412 |
| microsatellites uncover extraordinary diversity in native american land races and wild populations of cultivated sunflower. | the contemporary oilseed sunflower (helianthus annuus l.) gene pool is a product of multiple breeding and domestication bottlenecks. despite substantial phenotypic diversity, modest differences in molecular genetic diversity have been uncovered in anciently and recently domesticated sunflowers. the paucity of molecular marker polymorphisms in early analyses led to the hypothesis of a single domestication origin. phylogenetic analyses were performed on 47 domesticated and wild germplasm accession ... | 2003 | 12671746 |
| the ribosomal small-subunit protein s28 gene from helianthus annuus (asteraceae) is down-regulated in response to drought, high salinity, and abscisic acid. | a partial cdna for the ribosomal s28 gene from sunflower was initially cloned and identified to be down-regulated by high salinity, using differential display reverse transcriptase-polymerase chain reaction (pcr). using this sequence, a 502-base pair (bp) full-length cdna was cloned by rapid amplification of cdna ends. this cdna (designated ha-rps28) encodes a protein component of the small subunit of cytoplasmic ribosomes. the predicted 65 amino acid residue sequence of ha-rps28, with an estima ... | 2003 | 21659145 |
| disturbances of stem circumnutations evoked by wound-induced variation potentials in helianthus annuus l. | the relationship between evoked electrical activity and stem movements in three-week old sunflowers was demonstrated. electrical potential changes (recorded by ag/agcl extracellular electrodes) and time-lapse images (from a top view camera) were recorded and analyzed. a heat stimulus applied to the tip of one of the second pair of leaves evoked a variation potential, transmitted basipetally along one side of the stem. after stimulation, disturbances of circumnutations occurred. they included: ch ... | 2003 | 12655354 |
| resistance to broomrape (orobanche spp.) in sunflower (helianthus annuus l.) is temperature dependent. | the effects of various temperature regimes in the range 29-17/21-9 degrees c day/night on each stage of the parasitism process of orobanche cumana and o. aegyptiaca on sunflower were studied under controlled conditions in polyethylene bags. the response of the resistant sunflower variety 'ambar' was expressed as the degeneration of the parasite tissues after its establishment in the plant roots, and this stage was found to be temperature dependent. the degeneration rate of orobanche tubercles in ... | 2003 | 12654882 |
| accumulation of copper by roots, hypocotyls, cotyledons and leaves of sunflower (helianthus annuus l.). | the effects of different concentrations of copper sulfate on the growth of and the accumulation of cu2+ by root, hypocotyl, cotyledon and leaf growth of sunflower (helianthus annuus l.) were examined in this study. the concentrations of copper sulfate (cuso4 x 5h2o) used were in the range from 10(-5) to 10(-3) m. seedlings exposed to 10(-5) m cu2+ solution exhibited a 33% increase in growth (p < 0.005) when compared with the root length of the control. the seedlings treated with 10(-3) m cu2+ we ... | 2003 | 12653280 |
| sequence variability of a dehydrin gene within helianthus annuus. | dehydrins are proteins produced during the late stages of plant embryo development and following any environmental stimulus involving dehydration. in order to investigate the variability of a dehydrin-encoding gene (dhn1) in cultivated and wild sunflower (helianthus annuus) genotypes, near-complete alleles were isolated by the polymerase chain reaction and sequenced. all of the isolated sequences were found to contain the typical dehydrin domains, and interrupted by an intron. the number of nucl ... | 2003 | 12647054 |
| temperature-related non-homogeneous fatty acid desaturation in sunflower (helianthus annuus l.) seeds. | the fatty acid compositions of half-seeds and whole seeds of the temperature-dependent high-stearic-acid sunflower (helianthus annuus l.) mutant cas-14 were unexpectedly different. we found that there is a longitudinal gradient starting from the embryo up to the end of the cotyledon. the stearic acid content varied from 9.7 to 34.6% in seeds produced in a growth chamber (39/24 degrees c; day/night), and from 14.0 to 34.4% in seeds produced in the field during the summer season (35-40 degrees c i ... | 2003 | 12624771 |
| molecular mapping of the rf1 gene restoring pollen fertility in pet1-based f1 hybrids in sunflower (helianthus annuus l.). | up to now a single cytoplasmic male sterility (cms) source, pet1, is used worldwide for hybrid breeding in sunflower. introgression of the restorer gene rf1, responsible for fertility restoration, into new breeding material requires tightly linked markers to perform an efficient marker-assisted selection. a survey of 520 decamer primers by bulked segregant analyses identified five rapd markers linked to the restorer gene rf1. in a f(2) population of 183 individuals one of the rapd markers, opk13 ... | 2003 | 12595987 |
| simple sequence repeat map of the sunflower genome. | several independent molecular genetic linkage maps of varying density and completeness have been constructed for cultivated sunflower ( helianthus annuus l.). because of the dearth of sequence and probe-specific dna markers in the public domain, the various genetic maps of sunflower have not been integrated and a single reference map has not emerged. moreover, comparisons between maps have been confounded by multiple linkage group nomenclatures and the lack of common dna markers. the goal of the ... | 2002 | 12582890 |
| mapping and analysis of quantitative trait loci for grain oil content and agronomic traits using aflp and ssr in sunflower ( helianthus annuus l.). | crosses were made between two inbred lines of sunflower. parents and 118 f(3) families were planted in the field in a randomized complete block design in two replications. genetic control for some agronomical traits: grain weight by plant (gwp), 1,000-grain weight (tgw), percentage of oil in grain (pog) and sowing to flowering date (stf) was investigated in f(3) families and their parents. genetic variability was observed among the 118 f(3) families for all the traits studied. genetic gain was o ... | 2002 | 12582883 |
| occurrence of partial hybrids in wide crosses between sunflower ( helianthus annuus) and perennial species h. mollisand h. orgyalis. | hybridisation between the annual diploid sunflower ( helianthus annuus)and the perennial diploid species helianthus mollis and helianthus orgyalis was obtained by means of a normal crossing procedure or embryo rescue. hybridisation success was low. all plants examined cytologically appeared to be diploid. however, the phenotypes of these diploids were not intermediate between the parents and, despite great variation, they resembled the female parent-type predominantly. thirty five percent of pla ... | 2002 | 12582670 |
| the effects of air flow and stem flexure on the mechanical and hydraulic properties of the stems of sunflowers helianthus annuus l. | many studies have shown that wind affects plant development, causing them to develop shorter and usually stronger stems. many of these effects have been shown to be due to a response to mechanical flexing of the stem which is known as thigmomorphogenesis. however, it is not known how wind affects the hydraulic properties of stems, nor have the effects of air flow past leaves been examined in isolation from mechanical flexing. this study, therefore, used a factorial experiment to distinguish betw ... | 2003 | 12554727 |
| knotted1-like genes are strongly expressed in differentiated cell types in sunflower. | knotted1-like genes constitute a family of genes whose products are transcription factors involved in several aspects of plant development. in most species, these genes are expressed primarily in meristematic cells and are switched off as leaves develop. in this paper, the expression patterns of three kn1-like genes from sunflower (helianthus annuus l.) are described. northern blot experiments indicated that these genes are expressed at different levels in several organs of the plant, including ... | 2003 | 12554711 |
| vascular connections between the receptacle and empty achenes in sunflower (helianthus annuus l.). | empty achenes in sunflower, particularly in the centre of the capitulum, may be caused by poor vascularization. this hypothesis was tested by microscopic examination and translocation experiments. phloem and xylem were identified by fluorescence of aniline-blue-stained callose and autofluorescence, respectively. vascular strands that extended from the receptacle into empty achenes were regularly found in longitudinal sections. the phloem-mobile probe, carboxyfluorescein, was translocated from th ... | 2003 | 12493862 |
| two-dimensional electrophoresis patterns of total proteins, esterases and acid phosphatases from pollen, seeds and leaves of three cultivars of helianthus annuus l. | total proteins, esterases and acid phosphatases from pollen, seeds and leaves of three sunflower cultivars were separated by 2-d electrophoresis. the characteristic peptides for each cultivar were identified. the seeds and pollen of the cultivar wielkopolski contained 45 and 37 characteristic peptides, respectively, while the seeds and pollen of coril contained 73 and 35 characteristic peptides. the cultivar frankasol had the lowest total number of stained peptides in seeds and pollen, and the n ... | 2002 | 12441629 |
| bioactive terpenoids from sunflower leaves cv. peredovick. | the ch(2)cl(2) extract of dried leaves of helianthus annuus l. cv. peredovick(r) has yielded, in addition to the known sesquiterpene lactones annuolide e and leptocarpin, and the sesquiterpenes heliannuols a, c, d, f, g, h, i, the new bisnorsesquiterpene, annuionone e, and the new sesquiterpenes heliannuol l, helibisabonol a and helibisabonol b. structural elucidation was based on extensive spectral (one and two-dimensional nmr experiments) and theoretical studies. the sesquiterpenes heliannuol ... | 2002 | 12423890 |
| differential sensitivity of oleosins to proteolysis during oil body mobilization in sunflower seedlings. | until now, there has been no conclusive demonstration of any in vivo oleosin degradation at the early stages of oil body mobilization. the present work on sunflower (helianthus annuus l.) has demonstrated limited oleosin degradation during seed germination. seedling cotyledon homogenization in tris-urea buffer, followed by sds-page, revealed three oleosins (16, 17.5 and 20 kda). incubation of oil bodies with total soluble protein from 4-day-old seedlings resulted in oleosin degradation. in vitro ... | 2002 | 12407191 |
| ty1 /copia- and ty3 /gypsy-like dna sequences in helianthus species. | two repeated dna sequences isolated from a partial genomic dna library of helianthus annuus, p has13 and p has211, were shown to represent portions of the int gene of a ty3 /gypsy retroelement and of the rnase-hgene of a ty1 /copia retroelement, respectively. southern blotting patterns obtained by hybridizing the two probes to bglii- or drai-digested genomic dna from different helianthus species showed p has13 and p has211 were parts of dispersed repeats at least 8 and 7 kb in length, respective ... | 2002 | 12355209 |
| production and characterization of pyrolysis liquids from sunflower-pressed bagasse. | pyrolysis experiments on sunflower (helianthus annus l.)-pressed bagasse were performed in a fixed-bed tubular reactor. the effects of nitrogen flow rate and final pyrolysis temperature on the pyrolysis product yields and chemical compositions were investigated. the maximum bio-oil yield of 52.10 wt.% was obtained in a nitrogen atmosphere with flow rate of 50 ml min(-1) and at a pyrolysis temperature of 550 degrees c with a heating rate of 5 degrees c s(-1). the chemical characterization results ... | 2002 | 12227533 |
| characterization of the variation potential in sunflower. | a major candidate for intercellular signaling in higher plants is the stimulus-induced systemic change in membrane potential known as variation potential (vp). we investigated the mechanism of occurrence and long-distance propagation of vp in sunflower (helianthus annuus l.) plants. here we present evidence of the relationship among injury-induced changes in xylem tension, turgor pressure, and electrical potential. although locally applied wounding did trigger a change in membrane potential, it ... | 1997 | 12223859 |
| plant development in the absence of epiphytic microorganisms. | microorganisms (bacteria, fungi) are common residents of the roots, stems and leaves of higher plants. in order to explore the dependency of plant development on the presence of epiphytic microorganisms, the achenes (seeds) of sunflower (helianthus annuus l.) were sterilized and germinated under aseptic conditions. the sterility of the seedlings was determined with the agar impression method. in seedlings from non-sterile seeds (control) that were likewise raised in a germ-free environment, all ... | 2002 | 12216864 |
| behavior of metalaxyl and its pure r-enantiomer in sunflower plants (helianthus annus). | a possible stereospecific and/or stereoselective mechanism of biodegradation for metalaxyl and metalaxyl-m was studied to elucidate their behavior in sunflower plants and to compare their biodegradation. greenhouse experiments were carried out to confirm the same efficacy of the two fungicides against infections by plasmopara helianthi in sunflower plants. the two fungicides appear to have the same behavior regarding both the protection against plant infections and the mode of translocation and ... | 2002 | 12207477 |
| the potential for gene flow between cultivated and wild sunflower (helianthus annuus) in the united states. | the transfer of genes from crop plants to their wild relatives via hybridization has emerged as one of the primary risks associated with the commercialization of genetically engineered crops. although previous studies have revealed relatively high levels of hybridization when crop plants come into contact with their wild relatives, the frequency of such contact across the range of cultivation of any crop taxon is unknown. here we report the results of a multi-year, range-wide survey of the poten ... | 2002 | 21665757 |
| allelic diversity of simple sequence repeats among elite inbred lines of cultivated sunflower. | simple sequence repeat (ssr) markers were developed for cultivated sunflower (helianthus annuus l.) from the dna sequences of 970 clones isolated from genomic dna libraries enriched for (ca)n,, (ct)n, (caa)n, (cata)n, or (gata)n. the clones harbored 632 ssrs, of which 259 were unique. ssr markers were developed for 130 unique ssrs by designing and testing primers for 171 unique ssrs. of the total, 74 ssr markers were polymorphic when screened for length polymorphisms among 16 elite inbred lines. ... | 2002 | 12175068 |
| immuno-cytochemical localization of indole-3-acetic acid during induction of somatic embryogenesis in cultured sunflower embryos. | immature zygotic embryos of sunflower (helianthus annuus l.) produce somatic embryos when cultured on medium supplemented with a cytokinin as the sole source of exogenous growth regulators. the timing of the induction phase and subsequent morphogenic events have been well characterized in previous work. we address here the question of the role of endogenous indole-3-acetic acid (iaa), since auxins are known to have a crucial role in the induction of somatic embryogenesis in many other culture an ... | 2002 | 12172840 |
| formal syntheses of heliannuols a and d, allelochemicals from helianthus annus. | a synthesis of heliannuol a 1 is described involving hydrogenolysis of the cyclopropane fused benzoxepane compound 23 to generate the benzoxocane ring system of 1 and a fragmentation of methyl ether 25 furnished 4-methoxycurcuphenol 29, an advanced intermediate to heliannuol d 4. | 2002 | 12120159 |
| photosynthetic carbon reduction and carbon oxidation cycles are the main electron sinks for photosystem ii activity during a mild drought. | stomatal closure can explain the inhibition of net co2 uptake by a leaf subjected to a mild drought: the photosynthetic apparatus appears resistant to lack of water. changes in both the water content of leaves maintained in a constant environment and the ambient co2 molar fraction during measurements on well-hydrated leaves lead to similar effects on net co2 uptake and whole chain electron transport as estimated by leaf chlorophyll fluorescence measurements. in particular, it is shown that photo ... | 2002 | 12102514 |
| photosynthetic oxygen evolution at low water potential in leaf discs lacking an epidermis. | land plants encountering low water potentials (low psiw) close their stomata, restricting co2 entry and potentially photosynthesis. to determine the impact of stomatal closure, photosynthetic o2 evolution was investigated in leaf discs from sunflower (helianthus annuus l.) plants after removing the lower epidermis at low psiw. wounding was minimal as evidenced by o2 evolution nearly as rapid as that in intact discs. o2 evolution was maximal in 1% co2 in the peeled discs and was markedly inhibite ... | 2002 | 12102512 |
| partial hybridization in wide crosses between cultivated sunflower and the perennial helianthus species h. mollis and h. orgyalis. | to obtain introgressed sunflower lines with improved disease resistance, interspecific crosses were performed with foreign perennial species. we report on several unusual features displayed by these hybrid plants. the methods used to produce the kernels affected yield and genotypes of progeny. phenotypic traits and dna markers were investigated in 97 plants derived from cross-pollination between annual diploid cultivated sunflower (helianthus annuus) and the perennial diploid species h. mollis o ... | 2002 | 12096817 |
| sucrose metabolism and cellulose biosynthesis in sunflower hypocotyls. | the relationships between cellulose accumulation, changes in specific activities of enzymes of sucrose catabolism, levels of udp-glucose and rate of dark respiration were investigated in the subapical 1 cm-hypocotyl region of 10- to 14-day-old-sunflower seedlings (helianthus annuus l). the plants were grown under a light/dark regime in vermiculite that was soaked either with distilled water or half-strength hoagland nutrient solution. at this stage of seedling development, the hypocotyl had ceas ... | 2002 | 12060259 |
| plant available nitrogen from anaerobically digested sludge and septic tank sludge applied to crops grown in the tropics. | agricultural land is an attractive alternative for the disposal of biosolids since it utilises the recyclable nutrients in the production of crops. in thailand and other tropical regions, limited field-study information exists on the effect of biosolids management strategies on crop n utilisation and plant available n (pan) of biosolids. a field study was conducted to quantify the pan of the applied biosolids, and to evaluate the n uptake rates of some tropical crops. sunflower (helianthus annuu ... | 2002 | 12058820 |
| temperature and oxygen regulation of oleate desaturation in developing sunflower (helianthus annuus) seeds. | the effect of low (10 degrees c) and high (30 degrees c) temperature on in vivo oleate desaturation has been studied in developing sunflower (helianthus annuus l.) seeds under conditions of different oxygen availability (capitulum, detached achenes or peeled seeds). in seeds remaining in the capitulum, only a part of the oleate newly synthesized at high temperature was desaturated to linoleate, whereas more oleate than that synthesized de novo was desaturated at low temperature. achenes were onl ... | 2002 | 11982929 |
| cavitation fatigue and its reversal in sunflower (helianthus annuus l.). | "cavitation fatigue" is the increased susceptibility of a xylem conduit to cavitation as a result of its prior cavitation. it was investigated whether cavitation fatigue induced in vivo could be repaired in intact plants. sunflowers (helianthus annuus l.) were subjected to soil drought in the greenhouse. native embolism and vulnerability to cavitation was measured in well-watered controls and after 5 d and 10 d of controlled drought. a dramatic cavitation fatigue was observed where droughted xyl ... | 2002 | 11971926 |
| transcription of two sunflower (helianthus annuus l.) mitochondrial trna genes having different genetic origins. | the divergent transcription of two trna genes encoded in sunflower mitochondrial dna, proposed as genes of different genetic origin, has been studied in detail. the transcription initiation site (tis) for both transcript precursors has been identified by hybridization with in vitro (32)p-capped total rnas and primer extension. the location of two tiss and the analysis of distribution of sequence elements (motifs) usually present in higher plant mitochondrial promoters led to the identification o ... | 2002 | 11943457 |
| glyoxysomal acetoacetyl-coa thiolase and 3-oxoacyl-coa thiolase from sunflower cotyledons. | following chromatography on hydroxyapatite, the elution profile of the thiolase activity of the glyoxysomal fraction from sunflower (helianthus annuus l.) cotyledons exhibited two peaks when the enzyme activity was assayed with acetoacetyl-coa as substrate. only one of these two activity peaks was detectable when a long-chain thiolase substrate was used in the activity assay. the proteins (thiolase i and thiolase ii) underlying the two activity peaks detected with acetoacetyl-coa were of glyoxys ... | 2002 | 11925043 |
| isolation and characterisation of a cdna for a novel small hsp from sunflower suspension cell cultures. | a full-length cdna encoding a novel small heat shock protein (hahsp17.9) was isolated from a cdna library of sunflower (helianthus annuus cv. gloriasol). the deduced amino acid sequence exhibited high degree homology to the class i cytosolic shsps from other plant species, and contained all the conserved regions characteristic of this class of proteins. northern analyses showed that the transcript homologous to hahsp17.9 accumulates during heat shock in suspension cultured cells and in the diffe ... | 2001 | 11913786 |
| microsatellite isolation and characterization in sunflower (helianthus annuus l.). | development of microsatellite markers for sunflower (helianthus annuus l.) was performed to estimate their frequency, nature (structure), levels of polymorphism, usefulness for genotype identification, and calculation of genetic relationships between inbred lines representing the species diversity. isolation was performed from a small-insert genomic library followed by hybridization screening using oligonucleotide probes containing different nucleotide arrays. in this work, 503 unique microsatel ... | 2002 | 11908666 |
| application of very small force measurements in monitoring the response of sunflower to weak blue light. | a diaheliotropic response of sunflower, helianthus annuus, following a short pulse of low intensity blue light to a small area of leaf surface was examined with the application of the very low-force-measurements technique (the order of magnitude of 10(-5) n). one leaf from a pair was illuminated with a low intensity blue-light-pulse and the force was recorded, generated by the stem of the plant tending to bend. a very low phototropic effect in response to blue light alone was observed which coul ... | 2002 | 11897514 |
| isolation and characterization of undenatured chlorogenic acid free sunflower (helianthus annuus) proteins. | a method for obtaining sunflower protein (sfp) isolate, nondenatured and free of chlorogenic acid (cga), has been developed. during the isolating procedure, the extent of cga removal and protein denaturation was monitored. the defatted flour contained 2.5% cga as the main phenolic compound. phenolic compounds were removed by aqueous methanol (80%) extraction, before protein extraction at alkaline ph and diafiltration. differential scanning calorimetry and solubility tests indicated that no denat ... | 2002 | 11879063 |
| temperature effect on a high stearic acid sunflower mutant. | vegetable oil with elevated saturated fatty acid content may be useful for producing solid fat without hydrogenation or transesterification. under the nutritional point of view stearic acid is preferred to other saturated fatty acids because of its neutral effect on serum cholesterol lipoproteins. selection of a very high stearic acid sunflower (helianthus annuus l.) line (cas-14), with up to a 37.3% of stearic acid in the seed oil, and the relationship between the expression of this character a ... | 2002 | 11754941 |
| population ecology of wild sunflowers: effects of seed density and post-dispersal vertebrate seed predators. | assessing the effects of seed density on the population dynamics of wild plant species with crop relatives will be vital in determining the potential effects of introducing traits into wild populations as a result of crop-to-wild gene flow. we examined experimental sunflower (helianthus annuus) patches in eastern kansas to determine the effects of seed density and predation on seedling recruitment and seed production in the next generation. high seed density treatment plots had significantly mor ... | 2002 | 28547151 |
| regulation of nitric oxide (no) production by plant nitrate reductase in vivo and in vitro. | no (nitric oxide) production from sunflower plants (helianthus annuus l.), detached spinach leaves (spinacia oleracea l.), desalted spinach leaf extracts or commercial maize (zea mays l.) leaf nitrate reductase (nr, ec 1.6.6.1) was continuously followed as no emission into the gas phase by chemiluminescence detection, and its response to post-translational nr modulation was examined in vitro and in vivo. nr (purified or in crude extracts) in vitro produced no at saturating nadh and nitrite conce ... | 2002 | 11741046 |
| effect of dichlorophenolindophenol, dichlorophenolindophenol-sulfonate, and cytochrome c on redox capacity and simultaneous net h+/k+ fluxes in aeroponically grown seedling roots of sunflower (helianthus annuus l.): new evidence for a plasma membrane cn(-)-resistant redox chain. | excised roots from axenically grown sunflower seedlings reduced or oxidized exogenously added 2,6-dichlorophenolindophenol (dcip), dcip-sulfonate (dcip-s), and cytochrome c, and affected simultaneous h+/k+ net fluxes. experiments were performed with nonpretreated "living" and cn(-)-pretreated "poisoned" roots (control and cn(-)-roots). cn(-)-roots showed no h+/k+ net flux activity but still affected the redox state of the compounds tested. the hydrophobic electron acceptor dcip decreased the rat ... | 2001 | 11732339 |
| sunflower (helianthus annuus l.) response to broomrape (orobanche cernua loefl.) parasitism: induced synthesis and excretion of 7-hydroxylated simple coumarins. | the interaction of the parasitic plant orobanche cernua with resistant and susceptible cultivars of helianthus annuus l. was investigated. using different bioassays to evaluate the early stages of the parasite life cycle (germination, attachment, penetration, and establishment), differences were observed between o. cernua-resistant and o. cernua-susceptible sunflower varieties. germination of o. cernua seeds in the presence of resistant sunflower roots was approximately half that of germination ... | 2001 | 11604462 |
| edta and hedta effects on cd, cr, and ni uptake by helianthus annuus. | phytoremediation has shown great potential as an alternative treatment for the remediation of heavy-metal-contaminated soils and groundwater. however, the lack of a clear understanding pertaining to metal uptake/translocation mechanisms, enhancement amendments, and external effects on phytoremediation has hindered its full-scale application. the objective of this research was to investigate the ability of synthetic chelators for enhancing the phytoremediation of cadmium-, chromium- and nickel-co ... | 2001 | 11572587 |