Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
integration of transcriptomic and metabolic data reveals hub transcription factors involved in drought stress response in sunflower (helianthus annuus l.).by integration of transcriptional and metabolic profiles we identified pathways and hubs transcription factors regulated during drought conditions in sunflower, useful for applications in molecular and/or biotechnological breeding. drought is one of the most important environmental stresses that effects crop productivity in many agricultural regions. sunflower is tolerant to drought conditions but the mechanisms involved in this tolerance remain unclear at the molecular level. the aim of this st ...028639116
rhodococcus gannanensis sp. nov., a novel endophytic actinobacterium isolated from root of sunflower (helianthus annuus l.).a novel gram-positive, aerobic, non-motile strain, designated strain m1(t), was isolated from sunflower root (helianthus annuus l.) and characterised using a polyphasic taxonomic approach. the morphological and chemotaxonomic properties of the isolate were typical of those of members of the genus rhodococcus. phylogenetic analyses based on 16s rrna gene sequence showed that strain m1(t) belongs to the genus rhodococcus and clustered with rhodococcus canchipurensis mbrl 353(t) (99.1%, sequence si ...028488064
evolutionary origins of a bioactive peptide buried within preproalbumin.the de novo evolution of proteins is now considered a frequented route for biological innovation, but the genetic and biochemical processes that lead to each newly created protein are often poorly documented. the common sunflower (helianthus annuus) contains the unusual gene paws1 (preproalbumin with sfti-1) that encodes a precursor for seed storage albumin; however, in a region usually discarded during albumin maturation, its sequence is matured into sfti-1, a protease-inhibiting cyclic peptide ...024681618
oil body mobilization in sunflower seedlings is potentially regulated by thioredoxin h.thioredoxins are believed to mediate starch and protein mobilization in germinating cereals and dicotyledons. nothing is known about redox regulation of lipid mobilization in plants. the possible redox regulation by thioredoxin h (trx h) of a thiol-protease which degrades the oleosin coat of the oil body and its impacts on lipid mobilization was investigated in sunflower (helianthus annuus l.) seedlings. an alkaline proteolytic activity stimulated by light was detected in seedlings. in vitro, th ...022705588
root growth and nitrate-nitrogen leaching of catch crops following spring wheat.growing nitrogen (n) catch crops can reduce no(3)-n leaching after cultivating cereals. the objective of this study was to relate no(3)-n leaching to variation in the uptake of n and the size and distribution of the root systems of different catch crops species. in a 3-yr lysimeter experiment, phacelia (phacelia tanacetifolia benth.), sunflower (helianthus annuus l.), and a brassica species (yellow mustard [brassica alba l.] or a hybrid of turnip rape [b. rapa l. spp. oleifera (dc.) metzg.] and ...020400580
water relations of standard height and dwarf sunflower cultivars.development of early maturing short stature sunflower (helianthus annuus l.) cultivars followed the success of semi-dwarf cereals. although a number of breeding programs have recently released dwarf sunflower cultivars for production in western canada, the drought adaptability of dwarf cultivars has not been studied. therefore, field studies were conducted under rainfed conditions at two manitoba locations during 1994 and 1995 to compare seasonal water relations of 'sunwheat-103' (sw-103), a dwa ...011756266
effect of antioxidant butylated hydroxyl anisole on the thermal or oxidative stability of sunflower oil (helianthus annuus) by ultrasonic.the aim of the current investigation was to evaluate the efficiency of butylated hydroxyl anisole (bha) as an antioxidant in sunflower oil (helianthus annuus). the oxidation stability of sunflower oil have been investigated by the effects of varying amounts of bha. the antioxidant incorporated sunflower oil system and control edible oil were subjected to heating at 180 ± 5 °c continuously for a period of 4 h per day for consecutive 4 days. the parameters used to assess the thermal degradation an ...026788006
effect of soil temperature on transpiration in helianthus annuus. 193416652901
studies of the effect of artificial wind on growth and transpiration in helianthus annuus. 193516653304
effect of solar radiation on transpiration of helianthus annuus. 193516653274
effect of soil moisture on growth and transpiration in helianthus annuus. 194016653644
[a procedure for detection of hormonal substances through plantlets of helianthus annuus l]. 195114905732
a study of chlorophyll in a white mutant strain of helianthus annuus. 195416654692
[triterpene saponins in compositae. ii. saponins in helianthus annuus flowers]. 195613393981
absence of seed dormancy in a white mutant strain of helianthus annuus l. 195816655125
[research on the pigments in sunflower seeds (helianthus annuus l.). ii. caffeic acid]. 195914444398
[research on the pigments in sunflower seeds (helianthus annuus l.). i. chlorogenic acid]. 195914444397
effect of supra-optimal boron levels on respiration and carbohydrate metabolism of helianthus annuus. 196016655404
development of oil in the seed of helianthus annuus l. 196114448797
an arginase inhibitor from sunflower seeds (helianthus annuus). 196314067411
movement of tritiated water in the root system of helianthus annuus in the presence and absence of transpiration. 196516656097
factors affecting the development of the perithecial stage of powdery mildew of helianthus annuus l. in india. 19655876680
healing of experimental wounds with helianthus annus. 196514344963
effect of ethylene on auxin transport.ethylene was found to have no influence on auxin transport in hypocotyls of helianthus annuus and phaseolus vulgaris; coleoptiles of zea mays; petiole sections of gossypium hirsutum, phaseolus vulgaris, and coleus blumei. in the experiments described here, the tissues were treated with ethylene only during the 3 hours of polar transport. this short treatment is in contrast to the methods of others who found an effect of ethylene on auxin transport when plants grown in ethylene are used as experi ...19665990936
the influence of epiphytic bacteriae on auxin metabolism.plants are settled by epiphytic bacteriae able to convert tryptophan to iaa. this bacterial activity is abolished by chloramphenicol and streptomycin but not by penicillin. tryptophan conversion to iaa by plant parts or enzyme preparations is far more intensive in non-sterile conditions than in sterile ones. this is true for all investigated objects: helianthus annuus, phaseolus vulgaris, pisum sativum, triticum vulgare, zea mays, enteromorpha compressa, fucus vesiculosus, furcellaria fastigiata ...196624557783
active transport of ions across sunflower roots.the electrical potential difference across exuding roots of helianthus annuus in two strengths of complete culture solution was measured. the determination of the concentration of the major nutrient ions in the outside solution and the xylem sap enabled the nernst potential for each ion to be calculated. a comparison of the measured and calculated potentials indicated that the anions no3, so4, h2po4 and hpo4 were actively transported into the sap against the electrochemical potential gradient. t ...196624557888
substitution of germanium for boron in plant growth.the observation was confirmed that the addition of germanium dioxide (soluble form) to the nutrient solution can delay for a short time the appearance of boron deficiency symptoms on the shoots of sunflower plants (helianthus annuus l.). this appeared to be true, however, only under growing conditions in which the plants had a low boron requirement. the delay in the appearance of boron deficiency symptoms by administering germanium was demonstrated in sunflower plants ranging in age from 7 to 20 ...196616656385
auxin stimulation of ethylene evolution.the stimulation of ethylene production from seedling tissue of phascolus vulgaris, helianthus annuus and zea mays by growth regulators was inhibited by actinomycin d and puromycin and to a lesser extent by 2-thiouracil and p-fluorophenylalanine. it is concluded that the mechanism of action of growth regulators on the enhancement of ethylene production is the formation of enzymes involved in ethylene biogenesis.196616656291
allagochrome ii. effects of light and substrate on allagochrome and chlorogenic acid levels of incubated sunflower leaf discs.sunflower leaf discs incubated in the light on carbohydrate substrates exhibit several-fold increases in amounts of extractable allagochrome and chlorogenic acid. these changes are linear with time, and oxygen is required. the light effect saturates at approximately 600 muw/cm(2) "white" light, roughly the compensation point for photosynthesis. red light is as effective as white light. incubation in the dark, or in far red light, produces negligible changes in allagochrome and chlorogenic acid c ...196716656718
[the influence of growth substances on the development of bioelectric potentials in plant tissues].with hypocotyls of helianthus annuus, coleoptiles of zea mays and radicles of vicia faba seedlings the relations between auxin distribution and the development of electric potential differences were examined. a. experiments with helianthus seedlings. 1. removal of one of the cotyledons produces a transversal potential difference in the hypocotyl between the intact flank and that without cotyledon. with 10(-3)m kcl as contact solution the positive pole always lies on the intact side. 2. unilatera ...196724522454
[influence of d-leucine on helianthus annuus l]. 19675584638
[rhizosphere products of helianthus annuus and spinacia oleracea]. 19675584637
matric potentials of leaves.a pressure chamber was used to measure matric potentials of frozen and thawed leaves. significant matric potentials were demonstrated in sunflower (helianthus annuus l.), yew (taxus cuspidata sieb. and zucc.), and rhododendron (rhododendron roseum rehd.). matric potentials were particularly negative in rhododendron and were correlated with the amount of cell wall present and with the volume of water outside the leaf protoplasts at comparable matric potentials. it was concluded that matric forces ...196716656497
[the dose response relations in geotropic and phototropic stimulation: comparison of mono-with dicotyledonous plants].the increase in the geotropic curvatures of avena coleoptiles and lens epicotyls is linear and proportional to the time of stimulation. with low stimulation the sensitivities of both objects are equal; with longer stimulation the curvature of avena coleoptiles is somewhat greater.to increased phototropic irradiance lens epicotyls react with a first and a second positive curvature. between the two ranges of curvature (from about 10,000 up to 1,000,000 lx · sec) they are phototropically insensitiv ...196724522545
relationship of water potential to growth of leaves.a thermocouple psychrometer that measures water potentials of intact leaves was used to study the water potentials at which leaves grow. water potentials and water uptake during recovery from water deficits were measured simultaneously with leaves of sunflower (helianthus annuus l.), tomato (lycopersicon esculentum mill.), papaya (carica papaya l.), and abutilon striatum dickson. recovery occurred in 2 phases. the first was associated with elimination of water deficits; the second with cell enla ...196816656882
oxygenated fatty acids of oil from sunflower seeds after prolonged storage.chemical analysis of a number of sunflower (helianthus annuus) seed oil samples revealed a low and variable percentage of hydrogen bromide-reactive material. to characterize the compounds responsible for this reactivity, oil was extracted from selected introductions from uruguay, turkey, and yugoslavia that had been subjected to prolonged storage. two epoxy fatty acids and two conjugated dienolic acids were isolated from the methyl esters derived from these sunflower seed oils by using a combina ...196817805802
[submerse bacterial plant tumor on roots].spontaneous infections seem to indicate that not only the crown of herbeous plants is disposed to generate tumors. under substrate conditions such as those normally found at the crown, infections caused by agrobacterium tumefaciens will yield tumors in the entire area of the roots.roots of helianthus annuus and solanum lycopersicum grown in nutritive medium are disposed to tumor when given appropriate conditions of culture and inoculation. tissue culture, the most widely applied method for the a ...196824522818
[cytokinins in helianthus annuus].with two extraction procedures differing in the very first extraction steps two cytokinins from a total amount of 180 kg sunflower leaves could be isolated. one of these cytokinins is identified as zeatin by rf values, uv absorption, melting point of its picrate and its biological activity. the same data are given for the other cytokinin, which is very probably ribosylzeatin. the total free cytokinin content of sunflower leaves is calculated to be 50-90 μg of kinetin equivalent, or 5-9 μg of zea ...196824519838
active and passive ion transport in relation to transpiration in helianthus annuus.the effect of transpiration on the uptake of k, ca, no3 and so4 from two strengths of culture solution by helianthus plants was investigated. in the dilute solution transpiration had no effect on the uptake of all the ions studied. in the more concentrated solution the uptake of k, no3 and so4 were found to be sensitive to changes in water flux across the root. calcium uptake was found to be completely independent of water uptake in all the experiments.the results are interpreted in the light of ...196824519074
effects of flooding the root system of sunflower plants on the cytokin in content in the xylem sap.the severe chlorosis observed in the lower most of flooded sunflower plants (helianthus annuus l. cv. tall single) may lie initiated by a reduction in the import of cytokinins by the stoot from the flooded root system. experiment indicates that during 12 hours following the release of flooding, plants previously flooded for 72 hours or less recover their ability to exude sap when the root systems are aerated, and the root systems synthesize and export amino-acids to the shoot. plants flooded for ...196920925658
magnesium nutrition of two species of sunflower.helianthus annuus l., the common cultivated sunflower, and helianthus bolanderi gray subspecies exilis heiser, a form endemic on serpentine soils, were grown in culture solutions with widely varying mg levels. for comparable development, h. bolanderi exilis required higher levels of mg in the solution than h. annuus, both in the range of visual deficiency symptoms and in higher ranges.with 0.5 mm ca in the solutions, h. annuus reached a plateau in yield in the range of 0.25 to 2.0 mm mg in the s ...196916657149
 the feeding behaviour of oncopeltus fasciatus has been investigated. exploration of food materials is performed by means of watery saliva which is secreted onto surfaces of substrates and sucked back again. histological tests indicate that the animal preferably pierces the conducting system of the vicia faba plant. oncopeltus fasciatus secretes sheath material which coagulates and forms a lining to the path of the stylets during plant feeding. feeding on seeds (asclepias syriaca and helianthus a ...196928308908
decarboxylation and transport of auxin in segments of sunflower and cabbage roots.the movement of (14)c from indole-3-acetic acid (iaa) (14)c has been examined in 5 mm root segments of dark-grown seedlings of helianthus annuus and brassica oleracea. contaminants from distilled water, phosphate buffer and the razor-blade cutter increase the decarboxylation of iaa-(14)c, and cutting of root segments results in an activation of iaa-destroying enzymes at the cut surfaces. when these sources of errors were eliminated the following was shown: a) both in sunflower and cabbage there ...197024496770
leaf enlargement and metabolic rates in corn, soybean, and sunflower at various leaf water potentials.rates of photosynthesis, dark respiration, and leaf enlargement were studied in soil-grown corn (zea mays), soybean (glycine max), and sunflower (helianthus annuus) plants at various leaf water potentials. as leaf water potentials decreased, leaf enlargement was inhibited earlier and more severely than photosynthesis or respiration. except for low rates of enlargement, inhibition of leaf enlargement was similar in all three species, and was large when leaf water potentials dropped to about -4 ba ...197016657441
[tumorigenic action of nucleic acid of a bacteriophage present in tumoral tissue cultures of sunflower (helianthus annus)]. 19704987583
the amino acid sequence of helianthus annuus l. (sunflower) cyrochrome c deduced from chymotryptic peptides.peptides derived from digestion of 1 mumol of sunflower cytochrome c with chymotrypsin were separated by paper electrophoresis. the sequences of these peptides were determined by using the dansyl-edman method (gray & hartley, 1963) and confirmed by analysis of their amino acid composition. comparison of the set of peptides with the chymotryptic peptides of mung-bean (thompson, laycock, ramshaw & boulter, 1970) and wheat germ (stevens, glazer & smith, 1967) cytochrome c shows a clear homology. th ...19705500313
effect of environmental factors on cuticular transpiration resistance.measurements of the various diffusive resistances to water vapor transport within the leaves of sunflower plants (helianthus annuus) growing in a controlled environment chamber, were used to calculate values of cuticular resistance under a range of environmental conditions. cuticular resistance to water loss was found to be inversely related to the relative humidity of the surrounding air, and it is suggested that such a mechanism would form a useful adaptation to arid conditions, enabling plant ...197016657551
interaction between chemical mutagens with a delayed effect and metabolites of seeds : communication 2: changes in mutagenic activity.a study was made of chromosome aberrations in crepis capillaris seedlings, induced by the reaction products of chemical mutagens with seed metabolites. interaction between ethylenimine and seed metabolites of some plants of the family compositae (c. capillaris, taraxacum officinale, pyrethrum carneum, helianthus annuus) has been found to lead to the formation of highly active secondary mutagens whose action remains similar to that of ethylenimine, although the effect of ethylenimine is enhanced ...197124430019
evidence for a sodium influx pump in sunflower roots.transmembrane electrical potential differences in the cortical cells of the root of the sunflower (helianthus annuus) have been measured using microelectrodes. the plants were grown in culture solution with a range of sodium concentrations. it was found that increasing the external sodium concentration had virtually no effect on the transmembrane potential. the vacuolar content of sodium did not change significantly with the age of the tissue indicating that sodium was in flux equilibrium in our ...197124493457
the rate of photorespiration during photosynthesis and the relationship of the substrate of light respiration to the products of photosynthesis in sunflower leaves.single attached leaves of sunflower (helianthus annus l. "mennonite") were supplied (14)co(2) of constant specific radioactivity in gas mixtures containing various co(2) and o(2) concentrations. the (14)co(2) and co(2) fluxes were measured concurrently in an open system using an ionization chamber and infrared gas analyzer.the rate of photorespiration (5.7 +/- 0.3 mg co(2).dm(-2).(-1)) during photosynthesis in 21% o(2) at 25 c and 3,500 footcandles was over three times the rate of dark respirati ...197116657866
further investigations into hormone-directed transport in stems.the effect of iaa and three synthetic auxins on the upward movement of (32)p-orthophosphate and (14)c-sucrose has been investigated in decapitated stems of phaseolus vulgaris l., pisum sativum l., coleus blumci l. and helianthus annuus l. iaa greatly enhanced the accumulation of (32)p-orthophosphate in phaseolus vulgaris and pisum sativum, whereas in c. blumei and h. annuus it did not. 2,4-d like iaa, caused an increase in (14)c-sucrose and (32)p-orthophosphate accumulation in phaseolus vulgaris ...197124487549
[experiments and hypothesis concerning the primary action of auxin in elongation growth].1. sections of auxin-starved hypocotyls of helianthus annuus do not show any significant growth rate in water of buffers of ph\>-6. however, in buffers with ph-values of approximately 4, elongation growth is observed; its rate is similar to the rate of auxin-stimulated growth (after 6 h incubation). \3- this phenomenon of acid-induced growth occurs also under anaerobic conditions in contrast to auxin-induced growth (hager 1962). 2. intact cell wall aggregates of helianthus hypocotyls were obtain ...197124488103
biological quality of a lipoprotein concentrate from sunflower seed (helianthus annuus l.). 19715127161
method for determining solutes in the cell walls of leaves.a perfusion method is described whereby large discs of amphistomatous leaves are vacuum-perfused with water so that either successive fractions of perfusate may be analyzed for solutes or the infused water may be displaced and collected after equilibration with the leaf cells. with castor bean leaves, estimates of electrolyte concentration in cell wall water by the two methods were similar. total electrolytes in leaf cell wall water of castor beans (ricinus communis), sunflower (helianthus annuu ...197116657623
influence of ammonium and nitrate nutrition on the pyridine and adenine nucleotides of soybean and sunflower.total pyridine nucleotide concentration of root tissue for young soybean (glycine max var. bansei) and sunflower (helianthus annuus l. var. mammoth russian) plants is the same with either ammonium or nitrate, but nitrate results in an increased proportion of total oxidized plus reduced nadp (nadp[h]) seemingly at the expense of nad. the activity of nadh- and nadph-dependent forms of glutamic acid dehydrogenase is correlated with the ratio of total oxidized plus reduced nad to nadp(h). the low na ...197216657913
influence of ammonium and nitrate nutrition on enzymatic activity in soybean and sunflower.under conditions of controlled ph, nitrate and ammonium are equally effective in supporting the growth of young soybean (glycine max var. bansei) and sunflower (helianthus annuus l. var., mammoth russian) plans. soybean contains an active nitrate reductase in roots and leaves, but the low specific activity of this enzyme in sunflower leaves indicates a dependency upon the roots for nitrate reduction. suppression of nitrate reductase activity in sunflower leaves may be due to high concentrations ...197216657912
changes in cell membrane permeability in sunflower hypocotyls infected with sclerotinia sclerotiorum.influx and efflux of water and urea and electrolyte leakage are less for sunflower (helianthus annuus) hypocotyl sections above lesions caused by sclerotinia sclerotiorum than for those from healthy plants. urea uptake by sections above lesions is reduced (celery, squash, and tomato) or unchanged (bean) in other hosts after sclerotinia infection. efflux of urea from sunflower hypocotyls is biphasic, suggesting diffusion in series from two cellular compartments (cytoplasm and vacuole). efflux dur ...197216657961
auxin transport: a new synthetic inhibitor.the new synthetic plant growth regulator dpx1840 (3,3a-dihydro-2-(p-methoxyphenyl)-8h-pyrazolo [5,1-a] isoindol-8-one) was examined for its effects on auxin transport. at a concentration of 0.5 mm in the receiver agar cylinders dpx1840 significantly inhibited the basipetal transport of naphthaleneacetic acid-1-(14)c in stem sections of vigna sinensis endl., pisum sativum l., phaseolus vulgaris l., glycine max l., helianthus annuus l., gossypium hirsutum l., and zea mays l. without significantly ...197216658167
measurement of profiles of potassium activity and electrical potential in the intact root.profiles of potassium activity and electrical potential in the vacuoles of cells across the intact root of helianthus annuus have been measured. no gradient in either potassium activity or potential difference was detected from epidermis to pericycle. the trans-root electrical potential was found to be made up of two components, a large p.d. between the outside solution and the outer cells and a small p.d. at the pericycle-xylem interface. the results indicated that all the living cells of the r ...197224473821
diffusible gibberellins and phototropism in helianthus annuus.endogenous gibberellins were obtained in agar from the lower cut surface of upright sunflower shoot-tips. exposure to unilateral light of the tips standing on agar, with the lower cut ends bisected by a vertical glass barrier at right angles to incident light, resulted in approximately 8 times the quantity of gibberellins moving into the agar below the shaded side than into the agar below the illuminated side. these results are similar to those reported earlier for gibberellins and geotropism in ...197224477310
development and aging in helianthus annuus l. effects of the biological milieu of the apical meristem on patterns of development. 19724653614
on the variability of chlorogenic acid concentration.the plasticity of phenolic acid concentration in plants under various physiological stress situations raises questions concerning the ecological significance of such behavior. helianthus annuus l. is remarkably plastic with regard to chlorogenic and ischlorogenic acid concentrations when subjected to nitrogen deficiency, nacl-stress, short exposures to uv radiation or to combinations of these stresses. stress due to nacl has not previously been reported to produce this effect.i propose that chlo ...197228313129
endogenous gibberellin transport and biosynthesis in relation to geotropic induction of excised sunflower shoot-tips.surgical experiments on helianthus annuus and phaseolus multiflorus seedlings involving the application of auxin and gibberellin to decapitated plants, suggested that internode extension growth occurs under the controlling influence of apically synthesised gibberellin rather than auxin. studies were made of diffusible gibberellins from sunflower apical buds in relation to geotropic stimulation. approximately ten times as much gibberellin was obtained from lower than from upper tissues of horizon ...197224477810
isolation of plastids from sunflower cotyledons during germination.plastids from cotyledons of sunflower (helianthus annus l.) seedlings, germinated in the dark or in the light, were isolated by isopycnic sucrose density gradient centrifugation. at all stages of development the whole plastids contained triose phosphate isomerase, nadph-glyoxylate reductase, and l-dihydroxyphenylalanine oxidase, which were used as marker enzymes. at the beginning of germination the isopycnic density of whole plastids (proplastids) was about 1.22 g cm(-3). during development of p ...197216658132
fatty acid composition of sunflower (helianthus annus l.) oil as influenced by seed position. 19734785175
chloroplast response to low leaf water potentials: ii. role of osmotic potential.electron transport in chloroplasts isolated from desiccated sunflower (helianthus annuus l. cv. russian mammoth) leaves was compared with electron transport in sunflower chloroplasts in sorbitol-containing media having various osmotic potentials. in media having low osmotic potentials and dichloroindophenol as electron acceptor, the activity for electron transport was inhibited, but the inhibition was much less than that due to comparable desiccation in vivo. the inhibition at low osmotic potent ...197316658487
chloroplast response to low leaf water potentials: i. role of turgor.the effect of decreases in turgor on chloroplast activity was studied by measuring the photochemical activity of intact sunflower (helianthus annuus l. cv. russian mammoth) leaves having low water potentials. leaf turgor, calculated from leaf water potential and osmotic potential, was found to be affected by the dilution of cell contents by water in the cell walls, when osmotic potentials were measured with a thermocouple psychrometer. after the correction of measurements of leaf osmotic potenti ...197316658486
[studies on the change of microbody function in cotyledons of helianthus annuus l].the enzyme patterns in sunflower cotyledons indicate that the glyoxysomal function of microbodies is replaced by the peroxisomal function of these organelles during the transition from fat degradation to photosynthesis. the separation of the microbody population into glyoxysomes and peroxisomes during this transition period is reported. the mean difference in density between the activity peaks of glyoxysomal and peroxisomal marker enzymes on a sucrose gradient was calculated to be 0.007±0.004 g/ ...197324474308
evidence for two photoreactions and possible involvement of phytochrome in light-dependent stomatal opening.leaves of the xantha mutant of helianthus annuus have a higher rate of transpiration and a lower diffusive resistance in the light than in the dark. stomates of this nonphotosynthetic mutant open in the light and close in the dark.comparative studies of tobacco, xantha mutant, and wild-type sunflower stomatal opening over a range of light intensities in isolated portions of the spectrum reveal two patterns of response: (a) a low intensity opening in the green and far red characterized by partial ...197316658366
trypsin inhibitor content in some varieties of soya bean (glycine max l.) and sunflower seeds (helianthus annuus l.). 19744859576
distribution and development of nitrate reductase activity in germinating cotton seedlings.activity of nitrate reductase in roots and cotyledons of cotton seedings (gossypium hirsutum l. cv. deltapine 16) increased rapidly on germination, reaching a maximum after 1 day of imbibition. thereafter, activity declined until emergence and greening of the cotyledons, when it again began to increase steadily. germinating soybean (glycine max (l.) merrill cv. merit) and sunflower (helianthus annuus l. cv. peredovic) seedlings did not show the early peak of activity. the early peak depended on ...197416658724
efficiency and regulation of water transport in some woody and herbaceous species.the efficiency with which plants transport water is related to the water potential differences required to drive water fluxes from the soil to the leaf. a comparative study of two woody and three herbaceous species (citrus sinensis l. cv. koethen, pyrus kawakami l., helianthus annuus l. cv. mammoth russian, capsicum frutescens l. cv. yolo wonder, and sesamum indicum l. cv. glauca) indicated contrasts in water transport efficiency. depression of leaf water potential in response to transpiration i ...197416658853
translocation of radioactive carbon after the application of c-alanine and co(2) to sunflower leaves.(14)c-(ul)-l-alanine was applied to the surface of mature leaves at the second node of sunflower (helianthus annuus l. cv commander) plants, under illumination. the alanine was absorbed during a 4-hour period, and some of it was metabolized by the absorbing tissue. after a lag period of about 15 minutes from first application, distribution of (14)c through the plant proceeded in much the same pattern as when (14)co(2) is assimilated by similar leaves. most, if not all, of the (14)c exported from ...197416658645
changes in specific radioactivities of sunflower leaf metabolites during photosynthesis in (14)co 2 and (12)co 2 at normal and low oxygen.sunflower (helianthus annuus l.) leaf discs were exposed to (14)co2 or (14)co2 followed by (12)co2 in an open gas-exchange system with incoming gas of approximately 400 ppm co2 and either 21% or 1% o2. the (14)co2 and (12)co2 gas-exchange of the leaf discs were measured, and the specific activities of several metabolites were determined after different lengths of time. the rate of co2 efflux by the leaf discs was ca. 20% of the net photosynthetic rate at 21% o2 but no co2 efflux could be detecte ...197424442651
proceedings: polyploidy and habituation in a long-term callus culture as compared to crown gall tissue in vivo (helianthus annuus l.). 19744461472
water transport in plants: mechanism of apparent changes in resistance during absorption.leaf water potentials were measured at various rates of water absorption in whole plants and detached leaves of well-watered helianthus annuus l. the experiments were conducted in the steady state, where changes in leaf hydration did not affect the measurements but both the transpiration and growth components of absorption could be observed. calculations of the total plant resistance to water transport showed that the resistance at low fluxes was about 30 times the resistance at high fluxes. mos ...197424458419
chloroplast response to low leaf water potentials: iii. differing inhibition of electron transport and photophosphorylation.cyclic and noncyclic photophosphorylation and electron transport by photosystem 1, photosystem 2, and from water to methyl viologen ("whole chain") were studied in chloroplasts isolated from sunflower (helianthus annus l. var russian mammoth) leaves that had been desiccated to varying degrees. electron transport showed considerable inhibition at leaf water potentials of -9 bars when the chloroplasts were exposed to an uncoupler in vitro, and it continued to decline in activity as leaf water pote ...197416658727
changes in specific radioactivity of sunflower leaf metabolites during photosynthesis in (14)co 2 and (12)co 2 at three concentrations of co 2.sunflower (helianthus annuus l.) leaf discs were exposed to (14)co2 or (14)co2 followed by (12)co2 at 21% o2 and three different co2 concentrations. after intervals of up to 15 min, the specific activity of some photosynthetic intermediates was determined. at all co2 concentrations, the specific activity of 3-phosphoglyceric acid (3-pga) increased most rapidly and after 15 min of (14)co2 feeding was 92% (967 ppm co2), 87% (400 ppm co2) and 53% (115 ppm co2) of co2 supplied to the assimilation ch ...197424442699
temperature sensitivity of the latent phase in ethylene-induced elongation.the temperature sensitivity is reported for the latent period preceding ethylene-induced elongation in the adaxial half of the leaf petiole of helianthus annuus. when intact plants were exposed to 10 mul of ethylene/l of air over the temperature range 18 to 35 c, the minimum latent time was 62 minutes at 28 c and the maximum was 132 minutes at 18 c. the temperature coefficient, q(10), changed from 2.1 below 28 c, to 0.7 above. in 100 mul of ethylene/l of air, the latent time was reduced by 14% a ...197516659127
effect of osmotic stress on abscisic acid levels in xylem sap of sunflower (helianthus annuus l.).addition of an osmoticum (-12 bars) to the rooting medium of sunflowers (helianthus annuus l.) caused an increase in the level of abscisic acid (aba) present in xylem exudate subsequently collected from cut shoots. using tall and dwarf plants it was shown that there was a time lag in the appearance of increased levels of aba in tall plants when compared with dwarf plants. the results indicate that the leaves, rather than the roots are the site of synthesis of aba present in the xylem sap of osmo ...197524435170
effect of aeration on the flood-induced formation of adventitious roots and other changes in sunflower (helianthus annuus l.).the effects of flooding, flooding with aeration, and no flooding of the root system on shoot growth was studied in sunflower plants. the responses of shoots appear to be brought about by: (1) the anaerobic condition of the roots which causes stem dwarfing, chlorosis, and petiolar epinasty. (2) the presence of water in excess of field capacity (but not anoxia) around the roots which results in an increase in stem hypertrophy and the formation and growth of adventitious roots.197524430476
photosynthesis and photorespiratory co2 evolution of water-stressed sunflower leaves.rates of true photosynthesis (tps), apparent photosynthesis (aps) and photorespiration (pr) of sunflower (helianthus annuus l., var. mennonite) leaves were measured in air (21% o2, 300 vpm co2) at 25° c and 400 μeinsteins m(-2) s(-1) radiant flux density. the plants were water stressed by application of osmoticum (polyethylene glycol 4000) to the root system. tps and aps decreased linearly from maxima at-4 bar leaf-water potential (ψ) to become very small and zero respectively at about-18 bar ψ; ...197524430218
[isolation and characterization of 11-s-globulins from sunflower seeds (helianthus annuus l.)].the isolation of ii-s globulin, which is homogenous on sedimentation and gel chromatography (s020, w = ii,8 s), from sunflower seeds is achieved by cryoprecipitation from solutions of high ion strength (i approximately 0.5 to 1.8) with simultaneous reduction of the salt concentration (i approximately 0.3) and repeated gel chromatography on sephadex g-200. by this technique, the 7-s component which occurs in small quantity is isolated too. in solutions of low ion strength (i less than 0,3), the i ...19751233024
[quinic and isochlorogenic acids in sunflower seeds (helianthus annuus lin.)].quinic and isochlorogenic acids have been identified in sunflower's seeds (helianthus annuus lin.) by paper chromatography in presence of various solvents. quinic acid has been detected by color reaction and isochlorogenic by ultra-violet light.1975131623
[isolation and characterization of main albumin fractions of seeds from sunflower (helianthus annuus l.) and rape (brassica napus l.)].the main fractions of the albumins from sunflower and rapeseeds (isolated by means of precipitation with ammonium sulphate or tannin + caffeine and subsequent gel chromatography) are low-molecular, very basic proteins. their molecular weights range from 10 000 to 16 000, and their isoelectric points (determined by isoelectric focusing and free electrophoresis) are situated at ph greater than 10.0. from the circular dichroism in the wavelength range from 200 to 240 nm it is deduced that the main ...19755674
[response of flowering plant seedlings to the action of n-nitroso-n-methylurea].the influence of n-nitroso-n-methylurea on seedlings of two species of plants--cucurbita pepo l., helianthus annuus l.--was investigated. nmu was added in agar-agar, on which seedlings were growing. 0.02% concentration of nmu was used. in addition to the delay in growth and appearance of necrotic regions, also local overgrowth of cotyledons of c. pepo and overgrowth of hypocotyl and the base of cotyledons of h. annuus were observed. a histological analysis has shown that these swellings arise du ...19751210149
[reaction of the seedlings of flowering plants to the effects of imino-di-(paradimethylaminophenyl)-methane-aurine-00].the influence of auramine-00 on seedlings of three species of plants - cucurbita pepo l., helianthus annuus l., zea mays l.-was investigated. auramine was added in agar-agar, on which the seedlings were growing. two concentrations of auramine were used--0.001%. besides the delay in growth, also the formation of local overgrowth of cotyledons and hypocotyl of c. pepo, the base of cotyledons of h. annuus and mezocotyl of z. mays were observed. the histological analysis has shown these swellings to ...19751166654
assay of nitrogenase activity in intact plant systems.nitrogenase activity was assayed in intact system of cichorium intybus, a non-leguminous commercially cultivated crop, dahlia pinnata and helianthus annus, and taraxacum officinale, a common weed plant. the assay was made in fabricated cylinders which could accomodate pot with plants. in such kind of assay along with rhizosphere microflora, the nitrogen fixed by phyllosphere nitrogen fixing microflora could also be accounted, which otherwise was difficult to be accounted for.19751211718
enzymic capacities for chlorophyll biosynthesis. activation and de novo synthesis of enzymes.a previously published working model for the regulation of chlorophyll formation has been tested studying early steps of chlorophyll and porphyrin biosynthesis in developing cotyledons of helianthus annuus. the activities of delta-aminolevulinate synthetase (alas), delta-aminolevulinate dehydratase (alad), and the porphobilinogenase complex (pbgase) at any given time have been found to be strongly associated with endogenous developmental processes. highest activities in darkness have been observ ...1976132041
attempts to detect agrobacterium tumefaciens dna in crown-gall tumor tissue.primary and secondary crown gall tissue cultures were established from sunflower plants (helianthus annuus, variety mammoth russian) wound-inoculated with agrobacterium tumefaciens (smith and townsend) conn strain b(6). growth rates of tumor tissues and habituated healthy sunflower stem section tissues on basal medium lacking auxin and cytokinin were compared to those of healthy sunflower stem section tissue grown on the same medium with added phytohormones. no difference was detected in the the ...197616659607
water potential and stomatal resistance of sunflower and soybean subjected to water stress during various growth stages.plants of two varieties of soybean (glycine max (l.) merr.) and two varieties of sunflower (helianthus annuus l.) were grown in controlled environments and subjected to water stress at various stages of growth. leaf resistances and leaf water potentials were measured as stress developed. in soybeans the upper leaf surface had a higher resistance than the lower surface at all leaf water potentials and growth stages. resistance of the upper surface began to increase at a higher water potential and ...197616659712
chloroplast response to low leaf water potentials: iv. quantum yield is reduced.quantum yields were measured for co(2) fixation by sunflower (helianthus annuus l.) leaves having various water potentials and for dichlorophenolindophenol photoreduction by chloroplasts isolated from similar leaves having various water potentials. in red radiation, the quantum yield for co(2) was 0.076 for an attached sunflower leaf at a water potential of -3 to -4 bars but was 0.020 for the same leaf at -15.3 bars. after recovery to a water potential of -5 bars, the quantum yield rose to 0.060 ...197616659555
glutamine synthetase regulation by energy charge in sunflower roots.energy charge [(atp) + (1/2) (adp)]/[(atp) + (adp) + (amp)] and glutamine synthetase activity (transferase reaction) of roots increase in a near congruent manner when decotyledonized sunflower plants (helianthus annuus l. var. mammoth russian) are grown in nitrate for 9 days. replacement of nitrate with ammonium for the final 2 days leads to a higher energy charge and increased enzyme activity. similar correlations occur when nitrate plants are placed on a zero nitrogen regimen and when they are ...197616659478
a specifc inactivator of glyoxysomal isocitrate lyase from sunflower (helianthus annuus l.) cotyledons. 19761278372
isolation and bicarbonate transport of chloroplast envelope membranes from species of differing net photosynthetic efficiency.a three-phase discontinuous sucrose gradient yielded two fractions of chloroplast envelope membranes from spinach (spinacia oleracea l.), sunflower (helianthus annuus l.), and maize (zea mays l., mesophyll and undifferentiated chloroplasts). these species were selected to represent plants with fast photorespiration and slow net photosynthesis, fast photorespiration yet fast net photosynthesis, and slow photorespiration and fast net photosynthesis, respectively. buoyant densities were 1.08 and 1. ...197616659477
dissociation-recombination of intergenic sunflower alcohol dehydrogenase isozymes and relative isozyme activities.two unlinked genes, adh1 and adh2, control of the production of alcohol dehydrogenase (adh) in seeds of the animal sunflower (helianthus annuus). each gene is polymorphic, having f and s alleles. starch gel electrophoretic zymograms of the four possible double homozygotes have three bands, representing two homodimers and an intermediately migrating intergenic isozyme. zymograms of double heterozygotes consist of nine bands produced by ten isozymes: six intragenics and four intergenics, two of wh ...19761259707
lipid and fatty acid composition of chloroplast envelope membranes from species with differing net photosynthesis.lipid and fatty acid compositions were determined for chloroplast envelope membranes isolated from spinach (spinacia oleracea l.), sunflower (helianthus annuus l.), and maize (zea mays l.) leaves. the lipid composition was similar in sunflower, spinach, and undifferentiated maize chloroplast envelope membranes and different in maize mesophyll chloroplast envelope membranes. the predominant lipid constituents in all envelope membranes were monogalactosyldiglyceride (27 to 46%), digalactosyldiglyc ...197616659725
effect of benzyladenine on some enzymes of mitochondria and microbodies in excised sunflower cotyledons.benzyladenine (ba) increases the rate of expansion of dark-grown sunflower (helianthus annuus l.) cotyledons. the hormone slightly enhances the development of the two glyoxysomal enzymes, isocitrate lyase and malate synthetase, during the first 3 days of germination and greatly accelerates their decay in the 2 following days. the levels of the peroxisomal enzymes, glycolate oxidase and glyoxylate reductase, are enhanced by ba more than those of the two glyoxysomal enzymes. these effects of ba on ...197616659719
kinetin action on the development of microbody enzymes in sunflower cotyledons in the dark.removal of the roots from etiolated sunflower seedlings (helianthus annuus l.) at various stages of development resulted in a premature or enhanced decline of the activities of catalase (e.c. 1.11.1.6) and isocitrate lyase (e.c. 4.1.3.1) (glyoxysomes), and hydroxypyruvate reductase (e.c. 1.1.1.26) and glycolate oxidase (e.c. 1.1.3.1) (leaf peroxisomes) in the cotyledons. treatment of the cuttings with kinetin in the dark inhibited the loss of glyoxysomal enzyme activities and, at the same time, ...197624430605
structure and activity of chloroplasts of sunflower leaves having various water potentials.changes in membrane integrity, conformation and configuration, and in photosystem ii (ps ii) activity (measured as dichloroindophenol photoreduction) of sunflower (helianthus annuus l.) chloroplasts were studied after leaf tissue had been desiccated to various water potentials (ψ w ). fixatives for electron microscopy were adjusted osmotically to within 1 bar of the ψ w of the tissue to prevent rehydration during fixation. ps ii activity decreased to 50% of the control activity at a ψ w of-26 ba ...197624425086
Refresh
firstprev
12345678910...
nextlast
Displaying items 1 - 100 of 1423