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Vascular Bundles (vascular + bundle)
Selected AbstractsCompensative Effects of Chemical Regulation with Uniconazole on Physiological Damages Caused by Water Deficiency during the Grain Filling Stage of WheatJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 1 2008L. Duan Abstract Chemical regulation using plant growth regulators has proved to be potentially beneficial in water-saving agriculture. This experiment was conducted with winter wheat (Triticum aestivum L. cv. ,Jingdong 6') to study the effect of chemical regulation on alleviation of water deficit stress during the grain filling stage. Uniconazole, a plant growth regulator, was foliar sprayed at 85 % (adequate irrigation) and 60 % (deficit irrigation) field capacity. Results showed that the distribution of 3H-H2O in roots and flag leaf, characteristics of vascular bundle in primary roots and internode below spike, roots activity, transpiration rate and stomatal conductance of flag leaf were negatively affected by deficit irrigation after flowering. Foliar spraying at the early jointing stage with 13.5 gha,1 uniconazole was able to relieve and compensate for the harmful effects of deficit irrigation. Both the area of vascular bundle in primary roots and internode below the ear were increased by uniconazole, while root viability and their ability to absorb and transport water were increased. In the flag leaf, stomatal conductance was reduced to maintain the transpiration rate and water use efficiency (WUE) measured for a single wheat plant was higher. Uniconazole increased WUE by 25.0 % under adequate and 22 % under deficit irrigations. Under adequate irrigations, the 14C-assimilates export rate from flag leaf in 12 h (E12h) was increased by 65 % and 36 % in early and late filling stages, while under deficit irrigations, the E12h of uniconazole-treated plants exceeded that of control plants by 5 % and 34 % respectively. Physiological damages caused by water deficiency during the grain filling stage of wheat was alleviated by foliar spraying with uniconazole. [source] Plants, gall midges, and fungi: a three-component systemENTOMOLOGIA EXPERIMENTALIS ET APPLICATA, Issue 1 2008Odette Rohfritsch Abstract Larvae of gall midges (Diptera: Cecidomyiidae) induce the activation of plant cells, partial cell lysis, and differentiation of nutritive tissue. Specialized nutritive tissue is essential for larval development and plays a key role in gall organization. Midges of the tribes Lasiopterini and Asphondyliini, however, do not induce nutritive tissues as part of the formation of their galls. Instead, these ,ambrosia galls' contain fungal mycelia that line the interior surface of the chambers. The fungi not only provide Lasiopterini with nutrition, they also penetrate the stems, induce the lysis of the middle lamella of host cells, and open a channel to the vascular bundles. Larvae of Lasioptera arundinis (Schiner) (Lasiopterini) follow the fungus and feed on its mycelium along with adjoining stem cells of Phragmites australis (Cav.) Trin. (Poaceae). Eggs together with fungal conidia are deposited by the imago on the host. Asphondyliini use a needle-like ovipositor to introduce fungal conidia and eggs into the organs they attack. Larvae of Schizomyia galiorum Kieffer (Asphondyliini) are unable to initiate the gall or to develop in the flowers of Galium mollugo L. (Rubiaceae) without their fungal associate. In this article, I provide an overview of oviposition behaviour in the Asphondyliini, as well as descriptions of the ovipositor and the female post-abdominal segments. Gall formation by Lasiopterini and Asphondyliini and the role of associated fungi are discussed, as is the role of the fungus as an inquiline or an organizer of gall tissues and a nutritive device. [source] The chemical composition of essential oils and lipophilic extracts of Silphium integrifolium Michx. and S. trifoliatum L. leavesFLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2008Rados, aw Kowalski Abstract The research presented in this paper revealed that secretory ducts in leaf stalks and main nerves of leaf blades of S. integrifolium and S. trifoliatum were of schizogenic origin and were present in varied number around vascular bundles. GC,FID and GC,MS analyses of essential oils and lipophilic extracts made from leaves collected from tested Silphium species in 1999,2001 and 2007 indicated that sesquiterpene compounds were the main constituents: germacrene D, ,- caryophyllene, caryophyllene oxide and silphiperfol-6-en-5-one. Only the oil and extracts from S. integrifolium contained significant amounts of allo -aromadendr-9-ene (8.5 ± 4.2% in oil achieved in 1999,2001, as well as 3.7 ± 0.1% and 5.7 ± 0.3 µg/ml, respectively in essential oil and extract (1:10) from 2007). Besides volatile compounds, sterols such as , -sitosterol and stigmasterol as well as triterpene alcohols (,- amyrine and , -amyrine), higher alkanes, free fatty acids and their derivatives along with vitamin E were present in tested lipophilic extracts. Copyright © 2008 John Wiley & Sons, Ltd. [source] Die Blattanatomie eines schnell und eines langsam wachsenden Grases in Abhängigkeit von der StickstoffversorgungJOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 4 2001G. Schulte auf'm Erley Leaf anatomy of a fast- and a slow-growing grass as dependent on nitrogen supply The grass species Lolium perenne and Festuca rubra, originating from habitats with differing N-availability, differ in their relative growth rate. This is mainly caused by the higher specific leaf area of L. perenne compared to F. rubra. The leaf anatomy of both species was further investigated. The species were raised in growth chambers under high and low N-supply. The higher specific leaf area of L. perenne (27 mm2 mg,1) in relation to F. rubra (14 mm2 mg,1) was mainly caused by a lower leaf density (0.23 vs. 0.33 mg mm,3). The level of N-supply influenced both leaf density and leaf thickness. The leaf volume of L. perenne comprised higher fractions of epidermis and lower fractions of mesophyll and intercellular space compared to F. rubra. However, the discrepancy in leaf density between the species could not be explained by anatomical differences. Under low N-supply, the leaves of both species had higher amounts of vascular bundles and fibre cells and lower amounts of intercellular space, which partly explained the higher density of the leaves. It is concluded, that thinner cell walls and higher amounts of cytoplasm cause the higher specific leaf area of L. perenne. Die Grasarten Lolium perenne und Festuca rubra, die auf Standorten mit unterschiedlicher N-Verfügbarkeit beheimatet sind, unterscheiden sich in ihrer relativen Wachstumsrate. Der Hauptgrund dafür liegt in der höheren spezifischen Blattfläche von L. perenne gegenüber F. rubra. Von beiden Arten wurde die Blattanatomie näher untersucht, nachdem sie in Klimakammern unter einer hohen und einer niedrigen N-Versorgungsstufe angezogen worden waren. Es zeigte sich, daß sich die höhere spezifische Blattfläche von L. perenne (27 mm2 mg,1) gegenüber F. rubra (14 mm2 mg,1) auf eine niedrigere Blattdichte zurückführen ließ (0,23 gegenüber 0,33 mg mm,3). Die Höhe der N-Versorgung beeinflußte sowohl die Blattdichte als auch die Blattdicke. Die Blätter von L. perenne hatten gegenüber denen von F. rubra höhere Volumenanteile an Epidermis und geringere Anteile an Mesophyll und Interzellularen. Die Unterschiede in der Blattdichte zwischen den Spezies ließen sich hierdurch nicht erklären. Unter niedriger N-Versorgung hatten die Blätter beider Arten höhere Anteile an Leit- und Faserbündeln und weniger Interzellularraum, was die höhere Blattdichte unter niedriger N-Versorgung teilweise erklärt. Es wird gefolgert, daß insgesamt dünnere Zellwände und mehr Cytoplasma die höhere spezifische Blattfläche von L. perenne verursachen. [source] Accumulation and Dynamic Trends of Triterpenoid Saponin in Vegetative Organs of Achyranthus bidentataJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 2 2009Jinting Li Abstract The relationship between structural features of various vegetative organs and triterpenoid saponin accumulation in Achyranthus bidentata Blume was investigated using anatomy, histochemistry and phytochemistry. The results showed that the primary and secondary structures of roots, and the structures of stems and leaves of A. bidentata, were similar to those of ordinary dicotyledonous plants. The enlargement of its roots, however, was primarily associated with growth and differentiation of tertiary structures. There were collateral medullary vascular bundles in addition to the normal vascular bundles in the stem. The tertiary structure was not only main parts in the roots of A. bidentata, but also important storage region of triterpenoid saponin in its growth and development. The stem may be the essential transport organ of triterpenoid saponin, while palisade parenchyma may be the primary synthesis location. In November, the total quantity of triterpenoid saponin and overall biomass in the roots reach a maximum level. This was the best time, therefore, to harvest the roots and corresponded to the traditional harvest period. Despite the withered appearance of leaves, stems also contained substantial amounts of triterpenoid saponin, and it was recommended that the stems of A. bidentata should be used. [source] Fusarium oxysporum: exploring the molecular arsenal of a vascular wilt fungusMOLECULAR PLANT PATHOLOGY, Issue 5 2003Antonio Di Pietro SUMMARY Taxonomy: Vascular wilt fungus; Ascomycete although sexual stage is yet to be found. The most closely related teleomorphic group, Gibberella, is classified within the Pyrenomycetes. Host range: Very broad at the species level. More than 120 different formae speciales have been identified based on specificity to host species belonging to a wide range of plant families. Disease symptoms: Initial symptoms of vascular wilt include vein clearing and leaf epinasty, followed by stunting, yellowing of the lower leafs, progressive wilting of leaves and stem, defoliation and finally death of the plant. In cross-sections of the stem, a brown ring is evident in the area of the vascular bundles. Some formae speciales are not primarily vascular pathogens but cause foot- and rootrot or bulbrot. Economic importance: Causes severe losses on most vegetables and flowers, several field crops such as cotton and tobacco, plantation crops such as banana, plantain, coffee and sugarcane, and a few shade trees. Control: Use of resistant varieties is the only practical measure for controlling the disease in the field. Under greenhouse conditions, soil sterilization can be performed. Alternative control methods with potential for the future include soil solarization and biological control with antagonistic bacteria or fungi. Useful websites: http://www.fgsc.net/fus.htm, http://www-genome.wi.mit.edu/annotation/fungi/fusarium/, http://www.cbs.knaw.nl/fusarium/database.html [source] Systemic action of novel neonicotinoid insecticide IPP-10 and its effect on the feeding behaviour of Rhopalosiphum padi on wheatPEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 7 2010Li Cui Abstract BACKGROUND: IPP-10 is a novel neonicotinoid insecticide recently developed in China and has good activity against sucking insects. Studies were carried out to investigate the activity of IPP-10 against Rhopalosiphum padi L. RESULTS: The results demonstrated that IPP-10 had both contact and systemic activity, including acropetal and basipetal translocation in wheat vascular bundles. Starved R. padi were allowed to stay on wheat treated with a sublethal dose of IPP-10. The results of studying their feeding behaviour from an electrical penetration graph (EPG) revealed a decrease in total time and bout duration of xylem and phloem ingestion, but the total time and bout duration of phloem salivation were significantly prolonged. The frequency (7.03 ± 0.49 Hz) of the xylem ingestion waveform produced by aphids on wheat treated with IPP-10 was significantly lower than that of blank control aphids (8.20 ± 0.30 Hz). Consequently, aphids born on wheat treated with IPP-10 were obviously lighter and less fecund than the control aphids. CONCLUSION: These tests indicated that IPP-10 had both contact and systemic activity, with sublethal effects resulting in reduction in R. padi feeding behaviour, growth rate and fecundity. Copyright © 2010 Society of Chemical Industry [source] Genetic control over silica deposition in wheat awnsPHYSIOLOGIA PLANTARUM, Issue 1 2010Zvi Peleg Awns are long, stiff filamentous extensions of glumes in many grasses. In wheat, awns contribute up to 40% of the grain's photosynthetic assimilates, and assist in seed dispersal. Awns accumulate silica in epidermal hairs and papillae, and silica has been positively associated with yield and environmental stress tolerance. Here, the awns of a set of domesticated wheat genotypes and their direct progenitor, Triticum turgidum ssp. dicoccoides were characterized. In addition, the silica concentration in awns was genetically dissected in a tetraploid wheat population of recombinant inbred lines (RILs) derived from a cross between durum wheat (cv. Langdon) and wild emmer (accession G18-16). Scanning electron micrographs revealed a continuous silica layer under the cuticle. Extended silicification was identified in the epidermis cell wall and in sclerenchyma cells near the vascular bundles, but not in the stomata, suggesting that an active process directs the soluble silica away from the water evaporation stream. The number of silicified cells was linearly correlated to silica concentration in dry weight (DW), suggesting cellular control over silicification. Domesticated wheat awns contained up to 19% silica per DW, as compared with 7% in the wild accessions, suggesting selection pressure associated with the domestication process. Six quantitative trait loci (QTLs) for silica were identified in the awns, with a LOD score of 3.7,6.3, three of which overlapped genomic regions that contribute to high grain protein. Localization of silica in the awns and identification of QTLs help illuminate mechanisms associated with silica metabolism in wheat. [source] Isolation and characterization of a wound inducible phenylalanine ammonia-lyase gene (LsPAL1) from Romaine lettuce leavesPHYSIOLOGIA PLANTARUM, Issue 3 2004Reinaldo Campos Phenylalanine ammonia-lyase (PAL) catalyses the first step controlling the rate of phenylpropanoid metabolism. Wounding is a ubiquitous stress in nature and in the harvesting and preparation of fruits and vegetables that induces an increase in PAL activity, an accumulation of phenolic compounds and subsequent tissue browning. A wound-inducible PAL gene (LsPAL1) was isolated from Romaine lettuce by RT-PCR. The putative protein encoded by LsPAL1 is similar to predictive polypeptides sequences for other PALs. The kinetics of PAL mRNA accumulation is similar to those of induced PAL enzyme activity, with enzyme activity following mRNA accumulation by 12 h. Wound-induced PAL transcripts accumulated in cells close to the wound sites. Tissue printing showed that PAL mRNA was associated with tissue next to the epidermis and vascular bundles. A heterologous PAL protein was expressed in E. coli and was found to show significant PAL activity. [source] A simple floral fragrance and unusual osmophore structure in Cyclopogon elatus (Orchidaceae)PLANT BIOLOGY, Issue 4 2009A. P. Wiemer Abstract We studied gland morphology, anatomy and the chemical composition of the floral fragrance in the sweat bee-pollinated orchid Cyclopogon elatus. This is apparently the first such analysis for any Cyclopogon species, and one of very few studies in which both odour and osmophore are characterised in a nectar-rewarding orchid. Structures responsible for floral scent production were localised with neutral red staining and histochemical assays for lipids and starch. Their morphology and anatomy were studied with scanning electron microscopy and light microscopy thin sections, respectively. Fragrance samples were collected using SPME fibres and analysed with GC-MS. Anatomical evidence suggests that two parallel oval-shaped patches of unicellular trichomes on the abaxial surface of the labellum are osmophores. These are rich in stored lipids, while the parenchyma surrounding the vascular bundles contains starch. Only freshly opened flowers produced odours, while buds and withered flowers lacked scent. The chemical composition of the odour was dominated (>99.8%) by a single compound, trans-4,8-dimethyl-nona-1,3,7-triene (DMNT). Gland anatomy and position on the outside of the perianth are unusual for scent glands in general. The presence of DMNT, a nearly ubiquitous compound in herbivore-induced vegetative emissions and one of the major floral volatiles of Yucca, is not surprising in view of hypotheses on the evolutionary origin of flower scents, suggesting that wound volatiles are utilised as kairomonal attractants by florivores whose activities result in pollination. [source] Properties of ion channels in the protoplasts of the Mediterranean seagrass Posidonia oceanicaPLANT CELL & ENVIRONMENT, Issue 3 2004A. CARPANETO ABSTRACT Posidonia oceanica (L) Delile, a seagrass endemic of the Mediterranean sea, provides food and shelter to marine organisms. As environment contamination and variation in physico-chemical parameters may compromise the survival of the few Posidonia genotypes living in the Mediterranean, comprehending the molecular mechanisms controlling Posidonia growth and development is increasingly important. In the present study the properties of ion channels in P. oceanica plasma membranes studied by the patch-clamp technique in protoplasts obtained from the young non-photosynthetic leaves were investigated. In protoplasts that were presumably originated from sheath cells surrounding the vascular bundles of the leaves, an outward-rectifying time-dependent channel with a single channel conductance of 58 ± 2 pS which did not inactivate, was selective for potassium and impermeable to monovalent cations such as Na+, Li+ and Cs+ was identified. In the same protoplasts, an inward-rectifying channel that has a time-dependent component with single channel conductance of the order of 10 pS, a marked selectivity for potassium and no permeation to sodium was also identified, as was a third type of channel that did not display any ionic selectivity and was reversibly inhibited by tetraethylammonium and lanthanum. A comparison of Posidonia channel characteristics with channels identified in terrestrial plants and other halophytic plants is included. [source] Influence of substrate particle size and wet oxidation on physical surface structures and enzymatic hydrolysis of wheat strawBIOTECHNOLOGY PROGRESS, Issue 2 2009Mads Pedersen Abstract In the worldwide quest for producing biofuels from lignocellulosic biomass, the importance of the substrate pretreatment is becoming increasingly apparent. This work examined the effects of reducing the substrate particle sizes of wheat straw by grinding prior to wet oxidation and enzymatic hydrolysis. The yields of glucose and xylose were assessed after treatments with a benchmark cellulase system consisting of Celluclast 1.5 L (Trichoderma reesei) and Novozym 188 ,-glucosidase (Aspergillus niger). Both wet oxidized and not wet oxidized wheat straw particles gave increased glucose release with reduced particle size. After wet oxidation, the glucose release from the smallest particles (53,149 ,m) reached 90% of the theoretical maximum after 24 h of enzyme treatment. The corresponding glucose release from the wet oxidized reference samples (2,4 cm) was ,65% of the theoretical maximum. The xylose release only increased (by up to 39%) with particle size decrease for the straw particles that had not been wet oxidized. Wet oxidation pretreatment increased the enzymatic xylose release by 5.4 times and the glucose release by 1.8 times across all particle sizes. Comparison of scanning electron microscopy images of the straw particles revealed edged, nonspherical, porous particles with variable surface structures as a result of the grinding. Wet oxidation pretreatment tore up the surface structures of the particles to retain vascular bundles of xylem and phloem. The enzymatic hydrolysis left behind a significant amount of solid, apparently porous structures within all particles size groups of both the not wet oxidized and wet oxidized particles. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Nectaries and reproductive biology of Croton sarcopetalus (Euphorbiaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2001LEANDRO FREITAS Flower morphology, nectary structure, nectar chemical composition, breeding system, floral visitors and pollination were analysed in Croton sarcopetalus, a diclinous-monoecious shrub from Argentina. Male flowers have five receptacular nectaries, with no special vascular bundles, that consist of a uniserial epidermis with stomata subtended by a secretory parenchyma. Female flowers bear two different types of nectaries: inner (IN) and outer (ON) floral nectaries. IN, five in all, are structurally similar to the nectaries of male flowers. The five ON are vascularized, stalked, and composed of secretory, column-shaped epidermal cells without stomata subtended by secretory and ground parenchyma. In addition, ON act as post-floral nectaries secreting nectar during fruit ripening. Extrafloral nectaries (EFN) are located on petioles, stipules and leaf margins. Petiolar EFN are patelliform, stalked and anatomically similar to the ON of the female flower. Nectar sampled from all nectary types is hexose dominant, except for the ON of the female flower at the post-floral stage that is sucrose dominant. The species is self-compatible, but geitonogamous fertilization is rarely possible because male and female flowers are not usually open at the same time in the same individual, i.e. there is temporal dioecism. Flowers are visited by 22 insect species, wasps being the most important group of pollinators. No significant differences were found in fruit and seed set between natural and hand pollinated flowers. This pattern indicates that fruit production in this species is not pollen/pollinator limited and is mediated by a wide array of pollinators. [source] Comparative anatomy and systematics of Catasetinae (Orchidaceae)BOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 2 2001WILLIAM LOUIS STERN FLS Catasetinae consist of five genera of pseudobulbous Orchidaceae of the Neotropics. Anatomy is characterized by sunken, three-celled foliar hairs, mostly tetracytic stomatal apparatuses, superficial stomata, homogeneous mesophyll, foliar fibre bundles, collateral vascular bundles in a single row, xylem and phloem sclerenchyma associated with vascular bundles in leaves, conical, and rough-surfaced silica bodies adjacent to vascular bundle sclerenchyma; epidermal cells of pseudobulbs with heavily thickened outer walls, pseudobulb ground tissue of assimilatory and water-storage cells, scattered vascular bundles in pseudobulbs, and sclerenchyma and stegmata associated only with phloem of pseudobulbs; roots with thin-walled velamen cells and tenuous spirals of cell wall material, distinctive epivelamen cells, thin-walled exodermal cells and vascular tissue embedded in parenchyma. Except for mucilaginous idioblasts that occur in Mormodes and Cycnoches, there are few outstanding anatomical differences among the five genera. Thus, there are few anatomical characteristics of phylogenetic value. The monophyly of Catasetinae is supported by the presence of sunken foliar hairs. Our results support a close relationship between Clowesia and Catasetum, and between Mormodes and Cycnoches. Among the outgroups Pteroglossaspis is especially distinctive. [source] | |||||||||||||