Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
biphasic fluence response curves for induction of seed germination.fluence-response curves for the induction of seed germination after 24 hours pretreatment at 35 degrees c of rumex obtusifolius and arabidopsis thaliana show two phases of response: (a) a very low fluence-response (10(-4) - 10(-1) micromoles per square meter) and (b) a low fluence-response (1 - 10(3) micromoles per square meter).198516664390
a mutant of arabidopsis deficient in c(18:3) and c(16:3) leaf lipids.leaf tissue of a mutant of arabidopsis thaliana contains reduced levels of both 16:3 and 18:3 fatty acids and has correspondingly increased levels of the 16:2 and 18:2 precursors due to a single recessive nuclear mutation. the kinetics of in vivo labeling of lipids with [(14)c]acetate and quantitative analysis of the fatty acid compositions of individual lipids suggests that reduced activity of a glycerolipid n-3 desaturase is responsible for the altered lipid composition of the mutant. the effe ...198616664915
metabolism of unsaturated monogalactosyldiacylglycerol molecular species in arabidopsis thaliana reveals different sites and substrates for linolenic acid synthesis.synthesis of unsaturated monogalactosyldiacylglycerol (mgdg) was examined in a mutant of arabidopsis thaliana (l.) heynh. containing reduced levels of hexadecatrienoic (16:3) and linolenic (18:3) acids in leaf lipids. molecular species composition and labeling kinetics following the incorporation of exogenous [(14)c]fatty acids suggest that at least two pathways and multiple substrates are involved in desaturation of linoleic acid (18:2) to 18:3 for production of unsaturated galactolipids. a red ...198616664893
characterization of a chlorate-hypersensitive, high nitrate reductase arabidopsis thaliana mutant.a population of a. thaliana, produced by self-fertilization of ethylmethane sulfonate treated plants, was exposed to chlorate in the watering solution, and plants showing early susceptibility symptoms were rescued. among the progeny lines of these plants five were shown to be repeatably chlorate-hypersusceptible. one of these lines (designated c-4) possessed elevated activity of nitrate reductase (nr). the nr activity of mutant c-4 was higher than that of normal plants throughout the life cycle. ...198624247939
structure and expression of three light-harvesting chlorophyll a/b-binding protein genes in arabidopsis thaliana.the genome of arabidopsis thaliana is exceedingly small, in part because it lacks the large middle repetitive dna component characteristic of other plants. in this paper we have characterized a member of the low copy dna component: the gene family for the light-harvesting chlorophyll a/b-protein. this gene family is unusual in that it contains far fewer members than the 7-16 coding sequences for this protein found in other plants. we used cross-hybridization with a lemna gene encoding a light-ha ...19863012462
analysis of storage proteins in normal and aborted seeds from embryo-lethal mutants of arabidopsis thaliana.the major storage proteins isolated from wild-type seeds of arabidopsis thaliana (l.) heynh., strain "columbia", were studied by sucrose gradient centrifugation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page). both the hypocotyl and cotyledons of mature embryos contained abundant 12 s (cruciferin) and 2 s (arabin) proteins that appeared similar in size and subunit composition to the cruciferin (12 s) and napin (1.7 s) seed-storage proteins of brassica napus. the 12 s pro ...198624232640
carbon and nitrogen metabolism in a barley (hordeum vulgare l.) mutant with impaired chloroplast dicarboxylate transport.a mutant line, rpr79/2, of barley (hordeum vulgare l. cv. maris mink) has been isolated that has an apparent defect in photorespiratory nitrogen metabolism. the metabolism of (14)c-labelled glutamine, glutamate and 2-oxoglutarate indicates that the mutant has a greatly reduced ability to synthesise glutamate, especially in air, although in-vitro enzyme analysis indicates the presence of wild-type activities of glutamine synthetase (ec 6.3.1.2) glutamate synthase (ec 1.4.7.1 and ec 1.4.1.14) and ...198624232140
a single positive phototropic response induced with pulsed light in hypocotyls of arabidopsis thaliana seedlings.the fluence-response curves were measured for phototropic curvature in response to unilateral 450-nm light in hypocotyls of arabidopsis thaliana (l.) heynh. these show the classical "first positive" (peak curvature of 9-10°), "indifferent" and "second positive" phototropic response. reciprocity is valid only for the "first positive" response; the fluence requirements for its induction are similar to those for induction of the "first positive" phototropic response of coleoptiles. large angles of ...198624232138
fluxes through the prokaryotic and eukaryotic pathways of lipid synthesis in the '16:3' plant arabidopsis thaliana.the kinetics of [1-14c]acetate incorporation in arabidopsis thaliana l. (heyn) showed almost equal labelling of phosphatidylcholine (pc) and diacylgalactosylglycerol (dgg) at early times and the transfer of radioactivity from pc to dgg and diacyldigalactosylglycerol (ddg) at longer times. these kinetics demonstrated the parallel operation of the prokaryotic and eukaryotic pathways of lipid synthesis [roughan & slack (1982) annu. rev. plant physiol. 33, 97-132] in this tissue. at 2 h after the ap ...19863741384
organic solvents inhibit the mutagenicity of promutagens dimethylnitrosamine and methylbutylnitrosamine in a higher plant arabidopsis thaliana.the organic solvents dimethylsulphoxide (dmso), acetone, ethanol and dimethylformamide inhibited the mutagenic activity of the promutagens dimethylnitrosamine and methylbutylnitrosamine in a higher plant arabidopsis thaliana. in contrast, the direct-acting mutagens n-methyl-n'-nitro-n-nitrosoguanidine (mnng) and n-methyl-n-nitrosourea (mnu) were not affected by the organic solvents (with the exception of dmso). the effect of dmso on mnng- and mnu-mutagenesis is explained by its effect on the ph ...19863333268
molecular cloning and dna sequence of the arabidopsis thaliana alcohol dehydrogenase gene.arabidopsis thaliana provides an excellent experimental plant system for molecular genetics because of its remarkably small genome size, near absence of dispersed middle repetitive dna, and short life cycle. we have cloned and determined the nucleotide sequence of a single-copy gene from a. thaliana likely to be the gene encoding alcohol dehydrogenase (adh; alcohol:nad+ oxidoreductase, ec 1.1.1.1). the gene was isolated from a random recombinant library by cross-hybridization with a maize adh1 g ...19862937058
characterization of the genome of arabidopsis thaliana.the small crucifer arabidopsis thaliana has many useful features as an experimental organism for the study of plant molecular biology. it has a four-week life-cycle, only five chromosomes and a genome size less than half that of drosophila. to characterize the dna sequence organization of this plant, we have randomly selected 50 recombinant lambda clones containing inserts with an average length of 12,800 base-pairs and analyzed their content of repetitive and unique dna by various genome blot, ...19863701864
a binary vector for transferring genomic libraries to plants.the transformation of mutant plants with a complete recombinant library derived from wild-type dna followed by assay of transformed plants for complementation of the mutant phenotype is a promising method for the isolation of plant genes. the small genome of arabidopsis thaliana is a good candidate for attempting this so-called shotgun transformation. we present the properties of an a. thaliana genomic library cloned in a binary vector, pc22. this vector, designed to introduce genomic libraries ...19863534794
transformation of tobacco, tomato, potato, and arabidopsis thaliana using a binary ti vector system.using a binary tumor-inducing (ti) plasmid vector system, several plant species were transformed with a kanamycin resistance marker (neomycin phosphotransferase gene). four nicotiana species, seven tomato cultivars, two potato cultivars, and arabidopsis thaliana were transformed by the binary vector transformation method. in this method, various plant organ pieces were co-cultivated with agrobacterium tumefaciens cells carrying the binary vector, pga472, and a helper ti plasmid. we have also dem ...198616664795
transformation of arabidopsis thaliana with agrobacterium tumefaciens.transformed arabidopsis thaliana plants have been produced by a modified leaf disk transformation-regeneration method. leaf pieces from sterilely grown plants were precultured for 2 days and inoculated with an agrobacterium tumefaciens strain containing an avirulent ti (tumor-inducing) plasmid with a chimeric gene encoding hygromycin resistance. after cocultivation for 2 days, the leaf pieces were placed on a medium that selects for hygromycin resistance. shoots regenerated within 3 months and w ...198617792019
differential effects of a substituted pyridazinone, basf 13-338, on pathways of monogalactosyldiacylglycerol synthesis in arabidopsis.we have examined the effects of the substituted pyridazinone herbicide, 4-chloro-5-(dimethylamino)-2-phenyl-3(2h)pyridazinone (basf 13-338, sandoz 9785), on the desaturation of linoleic acid (18:2) on different molecular species of monogalactosyldiacylglycerol (mgdg) and phosphatidylcholine (pc) in leaf tissue of arabidopsis thaliana (l.) heynh. specific changes in lipid composition allowed identification of different substrates for desaturation of 18:2 to linolenic acid (18:3). 18:2/16:2 mgdg w ...198716665760
the influence of two culturing techniques on toxicity of four chemicals in arabidopsis.plots of arabidopsis thaliana l. (heynh.) plants were grown in two hydroponic systems, one using a solid rooting support media (vermiculite) and the other a flowing solution culture. both were tested with various concentrations of bromacil (5-bromo-3-sec-butyl-6-methyluracil), dichlobenil (2,6-dichlorobenzonitrile), copper sulfate (cuso4·5h2o) and 3-aminotriazole. the effects on biomass production were compared. plants treated with bromacil at concentrations up to 0.05 mg l(-1) were similarly re ...198724254186
the organic solvents acetone, ethanol and dimethylformamide potentiate the mutagenic activity of n-methyl-n'-nitro-n-nitrosoguanidine, but have no effect on the mutagenic potential of n-methyl-n-nitrosourea.the frequency of recessive chlorophyll and embryonic lethals included by n-methyl-n'-nitro-n-nitrosoguanidine (mnng) in arabidopsis thaliana was markedly increased when exposure of the seeds to mnng (3 h) was carried out in the presence of 4-12% acetone, 4-16% ethanol or 8-32% dimethylformamide. the enhancement of mnng mutagenicity was proportional to the concentrations of these organic solvents. in contrast, neither of them, applied at the same conditions and doses, influenced the mutagenic act ...19873657835
cloning quantitative trait loci by insertional mutagenesis.this study explores the theoretical potential of "insertional mutagenesis" (i.e., mutagenesis as a result of integration of novel dna sequences into the germ line), as a means of cloning quantitative trait loci (qtl). the approach presented is based on a direct search for mutagenic effects of a quantitative nature, and makes no assumptions as to the nature of the loci affecting quantitative trait value. since there are a very large number of potential insertion sites in the genome but only a lim ...198724241675
the effects of reduced amounts of lipid unsaturation on chloroplast ultrastructure and photosynthesis in a mutant of arabidopsis.a mutant of arabidopsis thaliana with reduced content of c(18:3) and c(16:3) fatty acids in membrane lipids exhibited a 45% reduction in the cross-sectional area of chloroplasts and had a decrease of similar magnitude in the amount of chloroplast lamellar membranes. the reduction in chloroplast size was partially compensated by a 45% increase in the number of chloroplasts per cell in the mutant. when expressed on a chlorophyll basis the rates of co(2)-fixation and photosynthetic electron transpo ...198716665443
genomic organization and nucleotide sequences of two histone h3 and two histone h4 genes of arabidopsis thaliana.two histone h3 and two histone h4 genes have been cloned from a λgtwesλ·b arabidopsis thaliana gene library. from their nucleotide sequences and from studies on their genomic organization, the following conclusions can be drawn: : 1) the nucleotide sequences of the two h3 coding regions show only 85% homology, but encode the same proteins. the arabidopsis h3 has the same amino acid sequence as its counterpart in corn, but differs from that of pea and wheat by replacement in position 90 of a seri ...198724301053
the relatively large beta-tubulin gene family of arabidopsis contains a member with an unusual transcribed 5' noncoding sequence.we have characterized the beta-tubulin gene family of arabidopsis thaliana. five distinct genes were cloned and analyzed by restriction enzyme mapping and cross-hybridization studies. three of the genes appear to be dispersed, whereas two others are linked within 1.5 kb of one another. the two linked genes are closely related and appear to have resulted from a fairly recent duplication. the three dispersed genes do not cross-hybridize to one another or to the two linked genes under highly string ...198724277495
the effects of light and gravity on the horizontal curvature of roots of gravitropic and agravitropic arabidopsis thaliana l.in an attempt to study and distinguish the effects of light and gravity on the direction of horizontal root growth, wild-type and an agravitropic mutant of arabidopsis thaliana l., aux-1 were examined. the mutant aux-1 seedling roots are agravitropic but do respond to light, thus allowing the effects of light and gravity on roots to be studied separately. it is shown that in addition to the recognized negative phototropic and positive gravitropic responses of the root, there are also horizontal ...198716665184
arabidopsis thaliana. 19873327474
purification and species distribution of rubisco activase.ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) activase, a soluble chloroplast protein which promotes light-dependent rubisco activation, was partially purified from spinach chloroplasts by ion-exchange and gel-filtration fast protein liquid chromatography. the protein could also be isolated using rate zonal centrifugation in sucrose gradients followed by conventional ion-exchange on deae-cellulose. the active enzyme was composed of 44 and 41 kilodalton subunits. antibodies to the act ...198716665546
isolation and characterization of plant genes coding for acetolactate synthase, the target enzyme for two classes of herbicides.acetolactate synthase (als) is the first common enzyme in the biosynthetic pathways to valine, isoleucine, and leucine. it is the target of two structurally unrelated classes of herbicides, the sulfonylureas and the imidazolinones. genomic clones encoding als have been isolated from the higher plants arabidopsis thaliana and nicotiana tabacum, using a yeast als gene as a heterologous hybridization probe. clones were positively identified by the homology of their deduced amino acid sequences with ...198716665813
studies on the introduction and mobility of the maize activator element in arabidopsis thaliana and daucus carota.we have co-transformed carrot (daucus carota) and arabidopsis thaliana with an agrobacterium tumefaciens non-tumorigenic t-dna carrying the maize transposable element activator (ac) and an agrobacterium rhizogenes ri t-dna. we present evidence that the ac element transposes in transformed root or root-derived callus cultures of both species. we show that fertile plants can be regenerated from transformed, root-derived callus cultures of arabidopsis, demonstrating the utility of the ri plasmid fo ...19872832144
characterization of the alpha-tubulin gene family of arabidopsis thaliana.the genome of arabidopsis thaliana (linnaeus) heynhold was shown to contain an alpha-tubulin gene family consisting of at least four genes and/or pseudogenes. the primary structure of a transcribed alpha-tubulin gene was determined. a comparison of the predicted amino acid sequence of the a. thaliana alpha-tubulin with the predicted amino acid sequences of alpha-tubulins of chlamydomonas reinhardtii, stylonychia lemnae, and homo spaiens reveals a high degree of homology; 90%, 87%, and 83% identi ...19873475704
acetosyringone promotes high efficiency transformation of arabidopsis thaliana explants by agrobacterium tumefaciens.high frequency transformation of arabidopsis thaliana leaf explants has been obtained using a disarmed ti plasmid containing the coding region of a neomycin phosphotransferase gene (npt ii) as a selectable marker. the rate of transformation ranged from 55 to 63 percent when acetosyringone (as), a natural wound response molecule, was added to an agrobacterium tumefaciens culture prior to incubation with leaf segments. without acetosyringone, the transformation rate was approximately 2 to 3 percen ...198724301191
cloning of an arabidopsis thaliana gene encoding 5-enolpyruvylshikimate-3-phosphate synthase: sequence analysis and manipulation to obtain glyphosate-tolerant plants.5-enolpyruvylshikimate-3-phosphate synthase (epsps), the target of the herbicide glyphosate, catalyzes an essential step in the shikimate pathway common to aromatic amino acid biosynthesis. we have cloned an epsp synthase gene from arabidopsis thaliana by hybridization with a petunia cdna probe. the arabidopsis gene is highly homologous to the petunia gene within the mature enzyme but is only 23% homologous in the chloroplast transit peptide portion. the arabidopsis gene contains seven introns i ...19873481024
a copia-like transposable element family in arabidopsis thaliana.the fast generation time, small genome size and extensive genetic map of the crucifer arabidopsis thaliana have made it the subject of an increasing number of studies in plant molecular genetics. as transposable elements have greatly facilitated genetic analysis in a variety of species, we have attempted to identify an endogenous a. thaliana transposable element. we report here the discovery of a family of such elements, which we refer to as ta1 elements. sequence analysis of one such element sh ...19882904123
nucleotide sequence of chloroplast cf1-atpase epsilon-subunit and elongator trnamet genes from arabidopsis thaliana. 19882904134
molecular cloning, genomic organization, expression and evolution of 12s seed storage protein genes of arabidopsis thaliana.we have identified a number of genes of the flowering plant arabidopsis thaliana that are abundantly expressed during embryogenesis. in this paper we discuss four of these genes, which comprise a gene family: complete genomic nucleotide sequence of two of the genes and partial sequence of the other two shows that they are all homologous to the 12s globulin seed storage protein genes of other angiosperms. the four genes fall into three subfamilies, as defined by cross-hybridization. one subfamily ...198824272631
positive selection for male-sterile mutants of arabidopsis lacking adenine phosphoribosyl transferase activity.three mutants of arabidopsis thaliana deficient in adenine phosphoribosyl transferase activity were isolated by selecting for germination of seeds on a medium containing 0.1 millimolar 2,6-diaminopurine. in each of the mutants, diaminopurine resistance was due to a recessive nuclear mutation at a locus designated apt. the mutants grow more slowly than wild type, and are male sterile due to abortion of pollen development after the meiotic divisions of the pollen mother cells. the reliability and ...198816666047
isolation and characterization of a starchless mutant of arabidopsis thaliana (l.) heynh lacking adpglucose pyrophosphorylase activity.a mutant of arabidopsis thaliana lacking adpglucose pyrophosphorylase activity (ec 2.7.7.27) was isolated (from a mutagenized population of plants) by screening for the absence of leaf starch. the mutant grows as vigorously as the wild type in continuous light but more slowly than the wild type in a 12 hours light/12 hours dark photoperiod. genetic analysis showed that the deficiency of both starch and adpglucose pyrophosphorylase activity were attributable to a single, nuclear, recessive mutati ...198816666044
presence of a chloroplast-like elongator trnamet gene in the mitochondrial genomes of soybean and arabidopsis thaliana.the nucleotide sequence of elongator trna(met) genes from soybean chloroplast and mitochondria and arabidopsis thaliana mitochondria have been determined. the mitochondrial trna(met) genes from soybean and a. thaliana are identical, and they differ from the soybean chloroplast trna(met) gene by only four nucleotides. analysis of the flanking regions indicates that the mitochondrial trna(met) gene is not present on a large chloroplast dna insertion in the mitochondrial genome, but it suggests tha ...19882838185
an evolutionarily conserved protein binding sequence upstream of a plant light-regulated gene.a protein factor, identified in nuclear extracts obtained from tomato (lycopersicon esculentum, solanaceae) and arabidopsis thaliana (brassicaceae) seedlings, specifically binds upstream sequences from the plant light-regulated gene family encoding the small subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (rbcs). rbcs upstream sequences from tomato, pea (pisum sativum, leguminosae), and arabidopsis are recognized by the factor. the factor recognition occurs via a short conserved seque ...19882902624
two strands of dna are not equivalent as probes in hybridizations at low stringency.only one of the two complementary strands of a restriction fragment hybridizes under low stringency conditions to a cloned arabidopsis thaliana genomic dna fragment. we propose that this effect is caused by the energetic nonequivalence of the two possible mismatched duplexes, resulting from the accumulation of mismatches and extrahelical bases. these mismatches will differ between the two duplexes. the choice of probe strand may therefore be important for the success of heterologous hybridizatio ...19883189816
restriction fragment length polymorphism linkage map for arabidopsis thaliana.we have constructed a restriction fragment length polymorphism linkage map for the nuclear genome of the flowering plant arabidopsis thaliana. the map, containing 90 randomly distributed molecular markers, is physically very dense; greater than 50% of the genome is within 1.9 centimorgans, or approximately 270 kilobase pairs, of the mapped dna fragments. the map was based on the meiotic segregation of markers in two different crosses. the restriction fragment length polymorphism linkage groups w ...19882901107
insensitivity to ethylene conferred by a dominant mutation in arabidopsis thaliana.ethylene influences a number of developmental processes and responses to stress in higher plants. the molecular basis for the action of ethylene was investigated in mutants of arabidopsis thaliana that have altered responses to ethylene. one mutant line, which has a dominant mutation at a locus designated etr, lacks a number of responses to ethylene that are present in the wild-type plant. these include inhibition of cell elongation, promotion of seed germination, enhancement of peroxidase activ ...198817747490
determination of the processing sites of an arabidopsis 2s albumin and characterization of the complete gene family.the most abundant isoform of the 2s albumin present in seeds of arabidopsis thaliana has been sequenced and the corresponding gene isolated. examination of the protein and dna sequences allows the determination of the exact proteolytic cleavage sites during posttranslational processing. like other 2s albumins, that of arabidopsis is made as a prepropeptide. after removal of the signal peptide, the propeptide is cleaved at four other points, giving two subunits linked by a disulfide bridge(s). co ...198816666238
characterization of highly repetitive sequences of arabidopsis thaliana.we have analyzed three classes of highly repetitive dna sequences of arabidopsis thaliana, composed of tamdemly repeated units of 180 bp, 500 bp, and 160 bp, respectively. the three families comprise approximately 2% of the arabidopsis genome and are the major component of the highly repetitive dna. the 500-bp element arose by duplication of one half of a 180-bp ancestor and insertion of a foreign segment between the two duplicated parts followed by amplification. the repeat elements contain occ ...19883405748
the α1-tubulin gene of arabidopsis thaliana: primary structure and preferential expression in flowers.the primary structure of the α1-tubulin gene of arabidopsis thaliana was determined and the 5' and 3' ends of its transcript were identified by s1 nuclease mapping experiments. the information obtained was used to (i) predict the amino acid sequence of the α1-tubulin, (ii) deduce the positions of introns within the α1-tubulin gene, and (iii) construct 3' noncoding gene-specific hybridization probes with which to study the pattern of α1-tubulin transcript accumulation in different tissues and at ...198824277562
chromosomal proteins of arabidopsis thaliana.in plants with large genomes, each of the classes of the histones (h1, h2a, h2b, h3 and h4) are not unique polypeptides, but rather families of closely related proteins that are called histone variants. the small genome and preponderance of single-copy dna in arabidopsis thaliana has led us to ask if this plant has such families of histone variants. we have thus isolated histones from arabidopsis and analyzed them on four polyacrylamide gel electrophoretic systems: an sds system; an acetic acid- ...198824272407
nucleotide sequence of an actin gene from arabidopsis thaliana.an 1830-bp genomic dna segment containing an arabidopsis thaliana actin gene, aac1, has been cloned and sequenced. the aac1 gene is present as a single-copy gene, but at least two other actin-like genes have been detected. comparison of the nucleotide sequence of aac1 with other cloned plant actin genes reveals four exons separated by three introns conservatively located in all plant actin genes. the deduced amino acid sequence has also been compared with actin protein sequences from other plant ...19883410320
plastocyanin of arabidopsis thaliana; isolation and characterization of the gene and chloroplast import of the precursor protein.a genomic clone encoding the plastocyanin precursor was isolated from an arabidopsis thaliana lambda embl3 library, with the help of a heterologous hybridization probe. the nucleotide (nt) sequence encoding the 171-amino acid precursor protein and 650 bp of the 5'-flanking region were determined. s1 nuclease mapping showed the arabidopsis coding region to be uninterrupted and the transcript to possess an untranslated leader of approx. 30 nt. the 5' region of the gene contains a 25-bp direct repe ...19883396882
a mutant of arabidopsis thaliana that exhibits chlorosis in air but not in atmospheres enriched in co(2).a mutant of arabidopsis thaliana (l.) heynh. which requires a high concentration (2% by volume) of atmospheric co(2) for growth has been isolated. unlike previous mutants of this type, this line does not have any apparent defect in photosynthetic co(2)-fixation, photorespiration, or photosynthetic electron transport. the mutant is abnormally susceptible to pigment bleaching in air but not in 2% co(2). the presence of normal or above-normal levels of antioxidants, carotenoids, and enzymes involve ...198816666132
tryptophan-requiring mutants of the plant arabidopsis thaliana.although amino acid auxotrophs are among the most frequently isolated mutations in microorganisms, no mutants that require amino acids have been isolated at the whole plant level. tryptophan-requiring mutants of the cruciferous plant arabidopsis thaliana have now been isolated by selecting for resistance to 5-methylanthranilic acid. the tryptophan requirement of one mutant, trpl-1, results from a defect in the second step of the tryptophan pathway catalyzed by anthranilate phosphoribosyl transfe ...198817796738
four genes in two diverged subfamilies encode the ribulose-1,5-bisphosphate carboxylase small subunit polypeptides of arabidopsis thaliana.the multigene family encoding the small subunit polypeptides of ribulose-1,5-bisphosphate carboxylase/oxygenase in the crucifer arabidopsis thaliana has been isolated and the organization and structure of the individual members determined. the family consists of four genes which have been divided into two subfamilies on the basis of linkage and dna and amino acid sequence similarities. three of the genes, designated ats1b, ats2b, and ats3b, reside in tandem on an 8 kb stretch of the chromosome. ...198824272625
a new locus (nia 1) in arabidopsis thaliana encoding nitrate reductase.we have isolated two nitrate reductase genes and their corresponding cdnas from arabidopsis thaliana. sequences of the two cdnas, when compared to a sequence of a barley cdna clone, confirm their identity as nitrate reductase clones and show that they are closely related. the two genes have been mapped using restriction fragment length polymorphisms; gnr2 is close to the previously identified chl-3 locus and is probably identical to it, while gnr1 maps to a new locus (nia1) on chromosome 1, near ...19882905260
identification of gtp-binding proteins in the plasma membrane of higher plants.antisera raised against a highly conserved amino acid sequence (g alpha-common peptide) of animal gs alpha, gi alpha, go alpha and gt alpha recognize, in plasma membranes of several higher plants, sets of proteins of mr = 37 and 31 kda (vicia faba), 36 and 31 kda (arabidopsis thaliana) and 38 and 34 kda (commelina communis). the a. thaliana proteins were solubilized and partially purified. they bind [35s]gtp gamma s with high affinity (apparent kd approximately 10 nm) and, with lower affinity, g ...19883142467
a th-1 mutant of arabidopsis thaliana is defective for a thiamin-phosphate-synthesizing enzyme: thiamin phosphate pyrophosphorylase.we have examined the activity of the thiamin phosphate pyrophosphorylase in arabidopsis thaliana wild type and in a mutant (th-1) which requires exogenous thiamin for growth. mutant and wild-type plants grown in 1 x 10(-7) molar thiamin were used for the examination of the production of thiamin and thiamin monophosphate (tmp) using 4-methyl-5-hydroxyethylthiazole phosphate and 2-methyl-4-amino-5-hydroxymethylpyrimidine pyrophosphate as substrates. while the wild-type strain formed both thiamin a ...198816666289
cold acclimation in arabidopsis thaliana.the abilities of two races of arabidopsis thaliana l. (heyn), landsberg erecta and columbia, to cold harden were examined. landsberg, grown at 22 to 24 degrees c, increased in freezing tolerance from an initial 50% lethal temperature (lt(50)) of about -3 degrees c to an lt(50) of about -6 degrees c after 24 hours at 4 degrees c; lt(50) values of -8 to -10 degrees c were achieved after 8 to 9 days at 4 degrees c. similar increases in freezing tolerance were obtained with columbia. in vitro transl ...198816666219
high-frequency plant regeneration from cultured cotyledons of arabidopsis thaliana.wild-type plants of arabidopsis thaliana strain "columbia" regenerated at a high frequency from immature cotyledons cultured on a shoot-inducing medium containing 1.0 mg/l 6-benzylaminopurine and 0.1 mg/l 1-naphthaleneacetic acid. cotyledon segments expanded rapidly and produced numerous shoots after 2-3 weeks in culture. regeneration occurred in the absence of the original shoot apex. hypocotyl segments from immature embryos produced root hairs and callus in culture but only rarely developed sh ...198824241755
altered regulation of lipid biosynthesis in a mutant of arabidopsis deficient in chloroplast glycerol-3-phosphate acyltransferase activity.the leaf membrane lipids of many plant species, including arabidopsis thaliana (l.) heynh., are synthesized by two complementary pathways that are associated with the chloroplast and the endoplasmic reticulum. by screening directly for alterations in lipid acyl-group composition, we have identified several mutants of arabidopsis that lack the plastid pathway because of a deficiency in activity of the first enzyme in the plastid pathway of glycerolipid synthesis, acyl-acp:sn-glycerol-3-phosphate ...198816593939
protein-bound ribulose bisphosphate correlates with deactivation of ribulose bisphosphate carboxylase in leaves.previous reports indicate that ribulose 1,5-bisphosphate (rubp) binds very tightly to inactive ribulose bisphosphate carboxylase (rubisco) in vitro. therefore, we decided to investigate whether there was evidence for tight binding of rubp associated with deactivation of rubisco in vivo. we modified a technique for rapidly separating ;free' metabolites from those bound to high molecular compounds. arabidopsis thaliana plants were illuminated at various irradiances before freezing the leaves in li ...198816666111
ammonia production and assimilation in glutamate synthase mutants of arabidopsis thaliana.ammonia production and assimilation(1) were examined in photorespiratory mutants of arabidopsis thaliana l. lacking ferredoxin-dependent glutamate synthase (fd-glus) activity. although photosynthesis was rapidly inhibited in these mutants in normal air, nh(4) (+) continued to accumulate. the accumulation of nh(4) (+) was also seen after an initial lag of 30 minutes in 2% o(2), 350 microliters per liter of co(2) and after 90 minutes in 2% o(2), 900 microliters per liter of co(2). the accumulation ...198816666091
plant expression vectors with the origin of replication of the w-type plasmid sa.a new class of binary vectors has been constructed, containing the origin of replication of the w-type plasmid sa. these vectors are designed to express foreign genes in plants under control of the tr gene 2' promoter or the promoter of a light-inducible ribulose-1,5-bisphosphate carboxylase small subunit gene of arabidopsis thaliana.19883231690
isolation and biochemical analysis of ethyl methanesulfonate-induced alcohol dehydrogenase null mutants of arabidopsis thaliana (l.) heynh.several mutants have been isolated at the arabidopsis thaliana (l.) heynh. alcohol dehydrogenase (adh) gene locus using allyl alcohol selection on ethyl methanesulfonate (ems)-mutagenized seeds. eleven mutants were isolated in the adh1-a electrophoretic allele, and 21 in the adh1-s allele. these null mutants are characterized by the absence of measurable adh activity and genetic data showed that the mutations were confined to the adh1 gene locus of arabidopsis. eleven mutants in the adh1-a backg ...19883377754
the beta-tubulin gene family of arabidopsis thaliana: preferential accumulation of the beta 1 transcript in roots.the genome of arabidopsis thaliana (l.) heynh. was shown to contain a beta-tubulin gene family consisting of at least seven distinct genes and/or pseudogenes. genomic clones of five different beta-tubulin genes and/or pseudogenes have been isolated and partially characterized. the complete nucleotide sequence of one a. thaliana beta-tubulin gene, designated beta 1, has been determined. a comparison of the predicted amino acid sequence of the a. thaliana beta 1-tubulin with the predicted sequence ...19883384336
molecular biology of plant growth and development. arabidopsis thaliana as an experimental system. 19883077979
cold induced gene expression in arabidopsis thaliana l.exposure of arabidopsis thaliana l. to an acclimation temperature (+4°c) results in a rapid increase of frost tolerance from -3°c to -7°c. this increase could be correlated to changes in soluble protein pattern. analysis of in vitro translation products from isolated mrna suggests that induction acts at the transcriptional level.198824240400
a starch deficient mutant of arabidopsis thaliana with low adpglucose pyrophosphorylase activity lacks one of the two subunits of the enzyme.a starch deficient mutant of arabidopsis thaliana (l.) heynh. has been isolated in which leaf extracts contain only about 5% as much activity of adpglucose pyrophosphorylase (ec 2.7.7.27) as the wild type. a single, nuclear mutation at a previously undescribed locus designated adg2 is responsible for the mutant phenotype. although the mutant contained only 5% as much adpglucose pyrophosphorylase activity as the wild type, it accumulated 40% as much starch when grown in a 12 hour photoperiod. the ...198816666440
fusicoccin activity and binding in arabidopsis thaliana.i have examined the activity and specific binding of the phytotoxin fusicoccin using arabidopsis thaliana l. col-o. fusicoccin (10 micromolar) stimulates both proton extrusion and enlargement in isolated arabidopsis leaf discs. radiolabeled fusicoccin specifically binds to membranes (13,000 to 100,000g subcellular fraction) from cultured cells of arabidopsis. the specific binding of this phytotoxin to putative receptor sites in arabidopsis membranes is both ph-sensitive (ph optimum = 5.5 to 6.0) ...198816666495
expression of light-harvesting chlorophyll a/b-protein genes is phytochrome-regulated in etiolated arabidopsis thaliana seedlings.phytochrome action results in a large and rapid increase in the light-harvesting chlorophyll a/b-protein (lhcp) mrna level in etiolated seedlings of arabidopsis thaliana: the rna increase is detectable within 1 hour after 1 minute red illumination, reaches a maximum 30-fold higher than the dark level at ca. 2 hours, and decays back to dark levels by about 8 hours after the brief red illumination. s1 nuclease analysis distinguishes two kinds of mrnas transcribed from the three members of the lhcp ...198816666462
high efficiency agrobacterium tumefaciens-mediated transformation of arabidopsis thaliana leaf and cotyledon explants.a highly efficient and fast agrobacterium-mediated leaf disc transformation system for the arabidopsis thaliana l. genotype c24 was developed. this protocol is also amenable to other ecotypes - as could be shown for landsberg erecta and wassllewskija. besides the hygromycin selection also the g418 and kanamycin selection were established. furthermore the described procedure is appliable not only to leaf explants but also to expanded cotyledons which proved to be an excellent alternative as expla ...198824240423
characterization of a polyubiquitin gene from arabidopsis thaliana.ubiquitin dna sequences were isolated from the higher plant arabidopsis thaliana l. by screening a lambda-gt11 genomic library with antibodies raised against oat and human ubiquitin. dna sequence analysis showed that the predicted protein sequence is 100% conserved with that found in oat and barley and differs by only three residues to that found in animals. this gene (ubq4) encodes a ubiquitin polyprotein with five repeats contiguously linked with no intervening sequences in the coding region a ...19882460733
structure and expression of spinach leaf cdna encoding ribulosebisphosphate carboxylase/oxygenase activase.ribulosebisphosphate carboxylase/oxygenase activase is a recently discovered enzyme that catalyzes the activation of ribulose-1,5-bisphosphate carboxylase/oxygenase ["rubisco"; ribulose-bisphosphate carboxylase; 3-phospho-d-glycerate carboxy-lyase (dimerizing), ec 4.1.1.39] in vivo. clones of rubisco activase cdna were isolated immunologically from spinach (spinacea oleracea l.) and arabidopsis thaliana libraries. sequence analysis of the spinach and arabidopsis cdnas identified consensus nucleo ...19883277181
isolation of a higher eukaryotic telomere from arabidopsis thaliana.we have developed a method for constructing genomic libraries enriched for telomeric dna sequences, enabling the isolation of telomeres from higher eukaryotic organisms with large chromosomes. the method was used to clone telomeric dna sequences from the flowering plant arabidopsis thaliana. a. thaliana telomeres are composed primarily of tandemly repeated blocks of the sequence 5'-ccctaaa-3' and are heterogeneous in size. genomic sequences that cross-hybridize at high stringency with a. thalian ...19883349525
transcriptional regulation of the arabidopsis thaliana chalcone synthase gene.we have cloned an arabidopsis thaliana chalcone synthase (chs) gene on the basis of cross-hybridization with a petroselinum hortense chs cdna clone. the protein sequence deduced from the a. thaliana chs dna sequence is at least 85% homologous to the chs sequences from p. hortense, antirrhinum majus, and petunia hybrida. southern blot analysis indicated that chs is a single-copy gene in a. thaliana. high-intensity light treatment of a. thaliana plants for 24 h caused a 50-fold increase in chs enz ...19883386631
isolation of genes expressed in specific tissues of arabidopsis thaliana by differential screening of a genomic library.the small genome size of arabidopsis thaliana allows the isolation of genes expressed in specific tissues and under controlled conditions by the differential screening of a genomic library, as has been shown previously for yeast and drosophila. cdna probes, based on poly(a)+ mrna isolated from different arabidopsis organs, were used in colony hybridizations with 1145 randomly chosen genomic clones, representing 27,000 kb of arabidopsis dna. twenty percent of the clones containing low-copy-number ...19882901388
identification of upstream regulatory elements involved in the developmental expression of the arabidopsis thaliana cab1 gene.we studied cis regulatory elements controlling the light-dependent organ-specific expression of arabidopsis thaliana chlorophyll a/b binding protein gene (cab1) by stably transforming tobacco plants using a tumor-inducing (ti) plasmid vector system. the results from the 5' and internal deletion analyses indicate that there are at least three cis-acting elements that are involved in the light-dependent developmental expression of cab1 gene. two such elements are located at the immediate upstream ...19883054877
intron existence predated the divergence of eukaryotes and prokaryotes.nucleotide sequences for the nuclear genes encoding chloroplast (gapa and gapb) and cytosolic (gapc) glyceraldehyde-3-phosphate dehydrogenases (gapdhs) from arabidopsis thaliana were determined. comparison of nucleotide sequences indicates that the divergence of chloroplast and cytosolic gapdh genes preceded the divergence of prokaryotes and eukaryotes. in addition, some intron-exon junctions are conserved among gapb, gapc, and chicken gapdh genes. these results provide evidence at the molecular ...19883055302
specialized binary vector for plant transformation: expression of the arabidopsis thaliana ahas gene in nicotiana tabacum.we constructed a cosmid vector, poca18, designed for transferring plant genomic libraries from agrobacterium tumefaciens to plants. clones from a genomic library of arabidopsis thaliana dna in poca 18 were propagated stably in both escherichia coli and a. tumefaciens. clones from the poca18 a. thaliana library were used to construct transgenic nicotiana tabacum plants; the dna inserts were transferred intact in 10 out of 16 transgenic n. tabacum plants examined but were partially deleted in six ...19883060849
structure and expression of the u5 snrna gene of arabidopsis thaliana. conserved upstream sequence elements in plant u-rna genes.we have previously characterized the u2 small nuclear (sn) rna gene family of arabidopsis thaliana. to find out the structural features of upstream and downstream non-coding regions that are shared by different u-rna genes in higher plants we have isolated the gene encoding a 125 nt-long u5 snrna of arabidopsis. activity of the cloned gene was demonstrated in stably transformed tobacco calli and by transient expression in transfected protoplasts of nicotiana plumbaginifolia. southern analysis in ...19883205713
sequence and nitrate regulation of the arabidopsis thaliana mrna encoding nitrate reductase, a metalloflavoprotein with three functional domains.the sequence of nitrate reductase (ec 1.6.6.1) mrna from the plant arabidopsis thaliana has been determined. a 3.0-kilobase-long cdna was isolated from a lambda gt10 cdna library of arabidopsis leaf poly(a)+ rna. the cdna hybridized to a 3.2-kilobase mrna whose level increased 15-fold in response to treatment of the plant with nitrate. an open reading frame encoding a 917 amino acid protein was found in the sequence. this protein is very similar to tobacco nitrate reductase, being greater than 8 ...19883393528
dual effect of light on the gibberellin- and nitrate-stimulated seed germination of sisymbrium officinale and arabidopsis thaliana.red light (r) has a dual effect on the seed germination of the two related species arabidopsis thaliana and sisymbrium officinale. the two species provide different means to separate the light-effects. in s. officinale, stimulation of germination by r depends on the stimultaneous presence of nitrate (light-effect i). the effect of both factors is completely blocked by tetcyclacis, an inhibitor of gibberellin (ga)-biosynthesis. addition of a mixture of gibberellins a(4) and a(7) (ga(4+7)) antagon ...198816665951
development of a plant transformation selection system based on expression of genes encoding gentamicin acetyltransferases.the development of selectable markers for transformation has been a major factor in the successful genetic manipulation of plants. a new selectable marker system has been developed based on bacterial gentamicin-3-n-acetyltransferases [aac(3)]. these enzymes inactivate aminoglycoside antibiotics by acetylation. two examples of aac(3) enzymes have been manipulated to be expressed in plants. chimeric aac(3)-iii and aac(3)-iv genes were assembled using the constitutively expressed cauliflower mosaic ...198816666057
agrobacterium tumefaciens-mediated transformation of arabidopsis thaliana root explants by using kanamycin selection.culture conditions were developed that induce arabidopsis thaliana (l.) heynh. root cuttings to regenerate shoots rapidly and at 100% efficiency. the shoots produce viable seeds in vitro or after rooting in soil. a transformation procedure for arabidopsis root explants based on kanamycin selection was established. by using this regeneration procedure and an agrobacterium tumor-inducing ti plasmid carrying a chimeric neomycin phosphotransferase ii gene (neo), transformed seed-producing plants wer ...198816593964
structure of u2 snrna genes of arabidopsis thaliana and their expression in electroporated plant protoplasts.we have characterized the u2 snrna gene family in the higher plant arabidopsis thaliana. it consists of 10-15 genes which do not appear to be closely clustered. six of the u2 genes were sequenced and the structure of the arabidopsis u2 rna termini was determined in order to define the coding regions. each of the genes codes for a distinct rna differing from the others by 2-13 point mutations, localized in the 3' part of the 196 nt-long rna. the upstream non-coding regions of all genes show stron ...198816453831
low temperature acclimation and treatment with exogenous abscisic acid induce common polypeptides in arabidopsis thaliana (l.) heynh.exogenously applied abscisic acid (aba) induced frost hardening of arabidopsis thaliana (l.) heynh. the freezing tolerance of a. thaliana plantlets treated with aba (15 mg/l) at a non-acclimating temperature (20 °c) appeared to increase even more rapidly than following a low temperature (4 °c) acclimation. analysis of in vivo-labelled soluble proteins by two-dimensional gel electrophoresis revealed several low temperature - or aba - induced proteins, which where not produced in non-acclimated pl ...198924232808
in vitro morphogenesis of arrested embryos from lethal mutants of arabidopsis thaliana.arrested embryos from lethal (emb) mutants of arabidopsis thaliana were rescued on a nutrient medium designed to promote plant regeneration from immature wild-type cotyledons. the best response was observed with mutant embryos arrested at the heart to cotyledon stages of development. embryos arrested at a globular stage produced callus but failed to turn green or form normal shoots in culture. many of the mutant plants produced in culture were unusually pale with abnormal leaves, rosettes, and p ...198924232790
mutation of a locus of arabidopsis thaliana confers resistance to the herbicide isoxaben.mutants resistant to the herbicide n-(3-[1-ethyl-1-methylpropyl]-5-isoxazolyl)-2,6,dimethoxybenzamide (isoxaben) were recovered from an m2 population of arabidopsis thaliana. two of these mutants, dh47 and dh48, had a high level of resistance in the homozygous state. crosses of these mutants to marker strains, and to each other, showed that each contained a mutation at a single locus tightly linked to lutescens, a marker on the fifth chromosome of a. thaliana. growth curves of these mutants and ...198916666725
three mitochondrial trna genes from arabidopsis thaliana: evidence for the conversion of a trnaphe gene into a trnatyr gene.three trna genes have been isolated from a genomic library of arabidopsis thaliana: a trnaser (gcu), a trnatyr (gua) and a trnaglu (uuc) genes. these genes are located closely on the same dna fragment. the trnaser and the trnaglu genes have both 99% sequence similarity with their mitochondrial counterparts from higher plants indicating that these three trna genes are mitochondrial. the trnatyr gene shows a particular high sequence similarity with the mitochondrial trnaphe pseudogene from maize, ...19892717403
immunochemically detectable phytochrome is present at normal levels but is photochemically nonfunctional in the hy 1 and hy 2 long hypocotyl mutants of arabidopsis.the hy 1 and hy 2 long hypocotyl mutants of arabidopsis thaliana contain less than 20% (the detection limit) of the phytochrome in wild-type tissue as measured by in vivo difference spectroscopy. in contrast, spectral measurements for the hy 3, hy 4, and hy 5 long hypocotyl mutants indicate that they each contain levels of phytochrome equivalent to the wild-type parent. immunoblot analysis using a monoclonal antibody directed against the chromophore-bearing region of etiolated-oat phytochrome de ...198924272903
in vivo detection of regulatory factor binding sites of arabidopsis thaliana adh.in vivo footprinting experiments have been used to analyze the binding of trans-acting regulatory factors in the 5' flanking region upstream of the alcohol dehydrogenase (adh) gene from arabidopsis thaliana. protein-dna interactions were detected by dimethyl sulfate footprinting and genomic sequencing, using an a. thaliana cell suspension culture that constitutively expressed the adh gene. several distinct footprinting domains have been characterized, and the potential effects of the correspondi ...198924272897
an auxin-regulated gene of arabidopsis thaliana encodes a dna-binding protein.we have isolated a single-copy gene from the plant arabidopsis thaliana, called dbp, which encodes a lysine-rich, dna-binding protein. the dbp protein has a molecular weight and a composition resembling histone h1. when the dbp gene was expressed in bacteria, the protein product bound dna nonspecifically. the dbp gene is expressed constitutively in all parts of the plant but is induced five times above this basal level in apical zones. in vitro hormone-depletion experiments showed that the expre ...198916666616
structural and functional analyses of arabidopsis thaliana chlorophyll a/b-binding protein (cab) promoters.arabidopsis thaliana carries three functional copies of the chlorophyll a/b-binding protein (cab) gene which code for an identical mature protein. dna sequence comparison of all three cab promoters indicated that cab2 and cab3 are more closely related compared to cab1. although the highest degree of homology was found between the tata box and -256 of cab3 promoter, suggesting that this region plays a major role in promoter function, this promoter regions are only 47% homologous. to study whether ...198924272796
amyloplasts are necessary for full gravitropic sensitivity in roots of arabidopsis thaliana.the observation that a starchless mutant (tc7) of arabidopsis thaliana (l.) heynh. is gravitropic (t. caspar and b.g. pickard, 1989, planta 177, 185-197) raises questions about the hypothesis that starch and amyloplasts play a role in gravity perception. we compared the kinetics of gravitropism in this starchless mutant and the wild-type (wt). wild-type roots are more responsive to gravity than tc7 roots as judged by several parameters: (1) vertically grown tc7 roots were not as oriented with re ...198924212342
gravitropism in a starchless mutant of arabidopsis : implications for the starch-statolith theory of gravity sensing.the starch-statolith theory of gravity reception has been tested with a mutant of arabidopsis thaliana (l.) heynh. which, lacking plastid phosphoglucomutase (ec 2.7.5.1) activity, does not synthesize starch. the hypocotyls and seedling roots of the mutant were examined by light and electron microscopy to confirm that they did not contain starch. in upright wild-type (wt) seedlings, starch-filled plastids in the starch sheath of the hypocotyl and in three of the five columellar layers of the root ...198924212341
fusicoccin-binding proteins in arabidopsis thaliana (l.) heynh. : characterization, solubilization, and photoaffinity labeling.using the novel radioligand, [(3)h]-9'-nor-fusicoccin-8'-alcohol, high affinity binding sites for fusicoccin were characterized in preparations from leaves of arabidopsis thaliana (l.) heynh. the binding site copartitioned with the plasmalemma marker, vanadate-sensitive k(+), mg(2+)-atpase, when microsomal fractions were further purified by aqueous two-phase partitioning in polyethylene glycol-dextran phase systems and sedimented at an equilibrium density of 1.17 grams per cubic centimeter in co ...198916666603
photorespiratory ammonia does not inhibit photosynthesis in glutamate synthase mutants of arabidopsis.exposure of ferredoxin-dependent glutamate synthase (ec 1.4.7.1) mutants of arabidopsis thaliana to photorespiratory conditions resulted in the accumulation of nh(4) (+) and the inhibition of photosynthesis. however, upon transfer from 2% o(2), 350 microliters per liter co(2), to 21% o(2), 350 microliters per liter co(2), net photosynthesis declined at a slower rate in methionine sulfoximine treated leaf discs relative to controls. the recovery of photosynthesis was also more rapid in mso-treate ...198916666572
rootcap structure in wild type and in a starchless mutant of arabidopsis.rootcaps of the wild type (wt) and of a starchless, gravitropic mutant (tc7) of arabidopsis thaliana l. were examined by electron microscopy to identify cellular polarities with respect to gravity. in columella cells, nuclei are located proximally, and the nuclear envelope is continuous with endoplasmic reticulum (er) that is in turn connected to nearby plasmodesmata. impregnation of er with osmium ferricyanide revealed numerous contacts between columella plastids and er in both genotypes. er is ...198911543603
the pattern of secondary root formation in curving roots of arabidopsis thaliana (l.) heynh.a gravitational stimulus was used to induce the curvature of the main root of arabidopsis thaliana. the number of secondary roots increased on the convex side and decreased on the concave side of any curved main root axes in comparison with straight roots used as the control. the same phenomenon was observed with the curved main roots of plants grown on a clinostat and of mutant plants exhibiting random root orientation. the data suggest that the pattern of lateral root formation is associated w ...198911539812
amyloplasts are necessary for full gravitropic sensitivity in roots of arabidopsis thaliana.the observation that a starchless mutant (tc7) of arabidopsis thaliana (l.) heynh. is gravitropic (t. caspar and b.g. pickard, 1989, planta 177, 185-197) raises questions about the hypothesis that starch and amyloplasts play a role in gravity perception. we compared the kinetics of gravitropism in this starchless mutant and the wild-type (wt). wild-type roots are more responsive to gravity than tc7 roots as judged by several parameters: (1) vertically grown tc7 roots were not as oriented with re ...198911539759
gravitropism in a starchless mutant of arabidopsis: implications for the starch-statolith theory of gravity sensing.the starch-statolith theory of gravity reception has been tested with a mutant of arabidopsis thaliana (l.) heynh. which, lacking plastid phosphoglucomutase (ec 2.7.5.1) activity, does not synthesize starch. the hypocotyls and seedling roots of the mutant were examined by light and electron microscopy to confirm that they did not contain starch. in upright wild-type (wt) seedlings, starch-filled plastids in the starch sheath of the hypocotyl and in three of the five columellar layers of the root ...198911539758
mutants of arabidopsis thaliana with altered phototropism.thirty five strains of arabidopsis thaliana (l.) heynh. have been identified with altered phototropic responses to 450-nm light. four of these mutants have been more thoroughly characterized. strain jk224 shows normal gravitropism and "second positive" phototropism. however, while the amplitude for "first positive" phototropism is the same as that in the wild-type, the threshold and fluence for the maximum response in "first positive" phototropism are shifted to higher fluence by a factor of 20- ...198911537724
root graviresponsiveness and cellular differentiation in wild-type and a starchless mutant of arabidopsis thaliana.primary roots of a starchless mutant of arabidopsis thaliana l. are strongly graviresponsive despite lacking amyloplasts in their columella cells. the ultrastructures of calyptrogen and peripheral cells in wild-type as compared to mutant seedlings are not significantly different. the largest difference in cellular differentiation in caps of mutant and wild-type roots is the relative volume of plastids in columella cells. plastids occupy 12.3% of the volume of columella cells in wild-type seedlin ...198911537658
mutants of arabidopsis thaliana with decreased amplitude in their phototropic response.two mutants of arabidopsis thaliana have been identified with decreased phototropism to 450-nanometer light. fluence-response relationships for these strains (zr8 and zr19) to single and multiple flashes of light show thresholds, curve shapes, and fluence for maximum curvature in first positive' phototropism which are the same as those of the wild type. similarly, there is no alteration from the wild type in the kinetics of curvature or in the optimum dark period separating sequential flashes in ...198911537461
influence of hook position on phototropic and gravitropic curvature by etiolated hypocotyls of arabidopsis thaliana.phototropic and gravitropic curvature by hypocotyls of arabidopsis thaliana is minimal when the side of the hook with the cotyledons attached is positioned toward the direction of tropistic curvature, and maximal when that side of the hook is positioned away from the direction of tropistic curvature. based on these data, it is proposed that the position of the hook with attached cotyledons affects curvature and not stimulus perception. a randomly oriented population of plants exhibited considera ...198911537453
Refresh
firstprev
12345678910...
nextlast
Displaying items 101 - 200 of 29220