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Helianthus Annuus L. (helianthus + annuu_l)
Selected AbstractsEffect of Drought Stress on Yield and Quality of Maize/Sunflower and Maize/Sorghum Intercrops for Biogas ProductionJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2010S. SchittenhelmArticle first published online: 16 FEB 2010 Abstract Intercropping represents an alternative to maize (Zea mays L.) monoculture to provide substrate for agricultural biogas production. Maize was intercropped with either sunflower (Helianthus annuus L.) or forage sorghum [Sorghum bicolor (L.) Moench] to determine the effect of seasonal water supply on yield and quality of the above-ground biomass as a fermentation substrate. The two intercrop partners were grown in alternating double rows at plant available soil water levels of 60,80 %, 40,50 % and 15,30 % under a foil tunnel during the years 2006 and 2007 at Braunschweig, Germany. Although the intercrop dry matter yields in each year increased with increasing soil moisture, the partner crops responded quite differently. While maize produced significantly greater biomass under high rather than low water supply in each year, forage sorghum exhibited a significant yield response only in 2006, and sunflower in none of the 2 years. Despite greatly different soil moisture contents, the contribution of sorghum to the intercrop dry matter yield was similar, averaging 43 % in 2006 and 40 % in 2007. Under conditions of moderate and no drought stress, sunflower had a dry matter yield proportion of roughly one-third in both years. In the severe drought treatment, however, sunflower contributed 37 % in 2006 and 54 % in 2007 to the total intercrop dry matter yield. The comparatively good performance of sunflower under conditions of low water supply is attributable to a fast early growth, which allows this crop to exploit the residual winter soil moisture. While the calculated methane-producing potential of the maize/sorghum intercrop was not affected by the level of water supply, the maize/sunflower intercrop in 2006 had a higher theoretically attainable specific methane yield under low and medium than under high water supply. Nevertheless, the effect of water regime on substrate composition within the intercrops was small in comparison with the large differences between the intercrops. [source] Exogenous Glycinebetaine and Salicylic Acid Application Improves Water Relations, Allometry and Quality of Hybrid Sunflower under Water Deficit ConditionsJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2009M. Hussain Abstract Limited water availability hampers the sustainability of crop production. Exogenous application of glycinebetaine (GB) and salicylic acid (SA) has been found very effective in reducing the adverse effects of water scarcity. This study was conducted to examine the possible role of exogenous GB and SA application in improving the growth and water relations of hybrid sunflower (Helianthus annuus L.) under different irrigation regimes. There were three levels of irrigation, viz. control (normal irrigations), water stress at budding stage (irrigation missing at budding stage) and water stress at flowering stage (FS) (irrigation missing at FS). GB and SA were applied exogenously at 100 and 0.724 mm respectively, each at the budding and FS. Control plants did not receive application of GB and SA. Water stress reduced the leaf area index (LAI), leaf area duration (LAD), crop growth rate (CGR), leaf relative water contents, water potential, osmotic potential, turgor pressure, achene yield and water use efficiency. Nevertheless, exogenous GB and SA application appreciably improved these attributes under water stress. However, exogenous GB application at the FS was more effective than other treatments. Net assimilation rate was not affected by water stress as well as application of GB and SA. The protein contents were considerably increased by water stress at different growth stages, but were reduced by exogenous GB and SA application. The effects of water stress and foliar application of GB were more pronounced when applied at FS than at the budding stage. Moreover, exogenous GB application was only advantageous under stress conditions. [source] Improving Drought Tolerance by Exogenous Application of Glycinebetaine and Salicylic Acid in SunflowerJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 3 2008M. Hussain Abstract Water shortage is a severe threat to the sustainability of crop production. Exogenous application of glycinebetaine (GB) and salicylic acid (SA) has been found very effective in reducing the adverse affects of drought stress. This study was conducted to examine the possible role of exogenous GB and SA application in improving the yield of hybrid sunflower (Helianthus annuus L.) under different irrigation regimes. There were three levels of irrigation, viz. control (normal irrigations), water stress at vegetative stage (irrigation missing at vegetative stage) and water stress at flowering stage (irrigation missing at flowering stage). GB and SA were applied exogenously at 100 and 0.724 mm, respectively, each at the vegetative and at the flowering stage. Control plants did not receive application of GB and SA. Water stress reduced the head diameter, number of achene, 1000-achene weight, achene yield and oil yield. Nevertheless, exogenous GB and SA application significantly improved these attributes under water stress. However, drought stress increased the free leaf proline and GB, and were further increased by exogenous application of GB and SA. However, exogenous GB application at the flowering stage was more effective than other treatments. Oil contents were also reduced under water stress; however, GB and SA application could not ameliorate the negative effect of water stress on achene oil contents. The effects of water stress and foliar application of GB were more pronounced when applied at the flowering stage than at the vegetative stage. Moreover, exogenous GB application was only beneficial under stress conditions. [source] Host Range of Australian Phoma ligulicola var. inoxydablis Isolates from PyrethrumJOURNAL OF PHYTOPATHOLOGY, Issue 7-8 2008S. J. Pethybridge Abstract Ray blight, caused by Phoma ligulicola var. inoxydablis is one of the most damaging diseases of pyrethrum (Tanacetum cinerariifolium [Trevir.] Sch. Bip.) in Australia. The pathogenicity of P. ligulicola var. inoxydablis to a range of ornamental and other plant species was tested to determine potential sources of inoculum into pyrethrum crops. Differences were identified in the host range of P. ligulicola var. inoxydablis isolates in this study in comparison with isolates reported from garden chrysanthemum (Chrysanthemum morifolium L.), most likely to be P. ligulicola var. ligulicola. Australian P. ligulicola var. inoxydablis isolates were unable to infect and cause disease following repeated inoculation to zinnia (Zinnia elegans L.), sunflower (Helianthus annuus L.), dahlia (Dahlia variabilis Desf.), and several cultivars of crisphead lettuce (Lactuca sativa L.). French marigold (Tagetes patula L.) was recorded as a susceptible host for this pathogen for the first time. Moreover, the susceptibility of annual chrysanthemum (Chrysanthemum carinatum L.) to infection by P. ligulicola var. inoxydablis was confirmed. Implications for disease management in Tasmanian pyrethrum fields are discussed. [source] Carbon Metabolism Alterations in Sunflower Plants Infected with the Sunflower Chlorotic Mottle VirusJOURNAL OF PHYTOPATHOLOGY, Issue 5 2003M. C. Arias Abstract Sunflower chlorotic mottle virus (SuCMoV) causes chlorotic mottling symptoms and important growth reductions and yield losses in sunflower (Helianthus annuus L., cv. Contiflor 7). This paper describes the effects of SuCMoV on some aspects of carbon metabolism of sunflower plants. After symptoms became evident, CO2 fixation rates decreased, nevertheless, soluble sugars and starch increased in infected leaves. High H2O2 accumulation, lipid peroxidation and chlorophyll degradation were, like the other changes, observed only after symptom expression. Increased soluble carbohydrate accumulation was not related to changes in , -amylase (EC 3.2.1.1) activity, nor in the activities of enzymes associated with sugar import and hydrolysis such as invertase (EC 3.2.1.26) and sucrose synthase (EC 2.4.1.13), suggesting it did not derive from starch hydrolysis nor increased sugar import. Rather, it may derive from recycling of cell components associated with the development of oxidative damage. The physiological alterations caused by this virus share many common features with the development of senescence. [source] Effects of Different Doses of Low Power Continuous Wave He,Ne Laser Radiation on Some Seed Thermodynamic and Germination Parameters, and Potential Enzymes Involved in Seed Germination of Sunflower (Helianthus annuus L.)PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2010Rashida Perveen In this study, water-soaked seeds of sunflower were exposed to He,Ne laser irradiation of different energies to determine whether or not He,Ne laser irradiation caused changes to seed thermodynamic and germination parameters as well as effects on the activities of germination enzymes. The experiment comprised four energy levels: 0 (control), 100, 300 and 500 mJ of laser energy and each treatment replicated four times arranged in a completely randomized design. The experimentation was performed under the greenhouse conditions in the net-house of the Department of Botany, University of Agriculture, Faisalabad. The seed thermodynamic parameters were calculated according to seed germination thermograms determined with a calorimeter at 25.8°C for 72 h. Various thermodynamic parameters of seed (,H, (,S)e, (,S)c, (,S)e/,t and (,S)c/,t) were affected significantly due to presowing laser treatment. Significant changes in seed germination parameters and enzyme activities were observed in seeds treated with He,Ne laser. The He,Ne laser seed treatment resulted in increased activities of amylase and protease. These results indicate that the low power continuous wave He,Ne laser light seed treatment has considerable biological effects on seed metabolism. This seed treatment technique can be potentially employed to enhance agricultural productivity. [source] Orange, yellow and white-cream: inheritance of carotenoid-based colour in sunflower pollenPLANT BIOLOGY, Issue 1 2010M. Fambrini Abstract Inheritance of pollen colour was studied in sunflower (Helianthus annuus L.) using three distinct pollen colour morphs: orange, yellow and white-cream. Orange is the most common colour of sunflower pollen, while the yellow morph is less frequent. These two types were observed in the inbred lines F11 and EF2L, respectively. White-cream pollen is a rare phenotype in nature, and was identified in a mutant, named white-cream pollen, recovered in the R2 generation of an in vitro regenerated plant. The F11 inbred line was used as starting material for in vitro regeneration. The carotenoid content of these three pollen morphs differed, and was extremely reduced in white-cream pollen. The phenotype of F1 populations obtained by reciprocal crosses revealed that the orange trait was dominant over both white-cream and yellow. Segregation of F2 populations of both crosses, orange × yellow and orange × white-cream, approached a 3:1 ratio, indicating the possibility of simple genetic control. By contrast, a complementation cross between the two lines with white-cream and yellow pollen produced F1 plants with orange pollen. The F2 populations of this cross-segregated as nine orange: four white-cream: four yellow. A model conforming to the involvement of two unlinked genes, here designated Y and O, can explain these results. Accessions with yellow pollen would have the genotype YYoo, the white-cream pollen mutant would have yyOO and the accession with orange pollen would have YYOO. Within F2 populations of the cross white-cream × yellow a new genotype, yyoo, with white-cream pollen was scored. The results of the cross yyoo × YYoo produced only F1 plants with yellow pollen, supporting a recessive epistatic model of inheritance between two loci. In this model, yy is epistatic on O and o. In F2 populations, the distributions of phenotypic classes suggested that the genetic control of carotenoid content is governed by major genes, with large effects segregating in a background of polygenic variation. These three pollen morphs can provide insight into the sequence in which genes act, as well into the biochemical pathway controlling carotenoid biosynthesis in anthers and the transfer of these different pigments into pollenkitt. [source] The interaction of light quality and irradiance with gibberellins, cytokinins and auxin in regulating growth of Helianthus annuus hypocotylsPLANT CELL & ENVIRONMENT, Issue 2 2007LEONID V. KUREPIN ABSTRACT A reduced red to far-red (R/FR) light ratio and low photosynthetically active radiation (PAR) irradiance are both strong signals for inducing etiolation growth of plant stems. Under natural field conditions, plants can be exposed to either a reduced R/FR ratio or lower PAR, or to a combination of both. We used Helianthus annuus L., the sunflower, to study the effect of reduced R/FR ratio, low PAR or their combination on hypocotyl elongation. To accomplish this, we attempted to uncouple light quality from light irradiance as factors controlling hypocotyl elongation. We measured alterations in the levels of endogenous gibberellins (GAs), cytokinins (CKs) and the auxin indole-3-acetic acid (IAA), and the effect of exogenous hormones on hypocotyl growth. As expected, both reduced R/FR ratio and lower PAR can significantly promote sunflower hypocotyl elongation when given separately. However, providing the reduced R/FR ratio at a low PAR resulted in the greatest hypocotyl growth, and this was accompanied by significantly higher levels of endogenous IAA, GA1, GA8, GA20 and of a wide range of CKs. Providing a reduced R/FR ratio under normal PAR also significantly increased growth and again gave significantly higher levels of endogenous IAA, GAs and CKs. However, only under the de-etiolating influence of a normal R/FR ratio did lowering PAR significantly increase levels of GA1, GA8 and GA20. We thus conclude that light quality (e.g. the R/FR ratio) is the most important component of shade for controlling hypocotyl growth and elevated growth hormone content. [source] Effect of source,sink ratio on seed set and filling in sunflower (Helianthus annuus L.)PLANT CELL & ENVIRONMENT, Issue 10 2003M. ALKIO ABSTRACT Poor seed development in sunflower may result from insufficient assimilate supply (source limitation). To test this hypothesis, the effects of changed source,sink ratio on seed set (measured as percentage of empty achenes) and seed filling (measured as dry mass per filled achene) in individual plants were investigated. Source,sink ratio, defined as leaf area per floret (LAF), was experimentally altered using invasive (floret removal, defoliation) and non-invasive (pulse of chilling, short days or shading during leaf or floret initiation) treatments. Shading at floret initiation proved the most effective non-invasive method. Generally, an increase, or decrease, in LAF improved, or impaired, both seed set and filling. Increasing LAF by 2.0 cm2[95% confidence interval (1.5, 2.5)] decreased the percentage of empty achenes by 36.9%-points (,41.9, ,30.9) and increased dry mass per filled achene by 20.1 mg (13.6, 26.7) in the capitulum centre. The effect of source,sink ratio on seed set was always strongest in the centre, whereas peripheral whorls were not affected. Achene mass was affected in all parts of the capitulum. It is concluded that source limitation is a major cause for empty achenes in sunflower plants grown under non-stress conditions. [source] | ||||||||||