JOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2008
ANVAR SHALMASHI
ABSTRACT This study examines subcritical water extraction (SCWE) of caffeine from black tea leaf. The effects of various operating conditions such as water temperature (100, 125, 150 and 175C), water flow rate (1, 2 and 4 g/min), mean particle size (0.5, 1 and 2 mm) on extraction yield and rate were determined. SCWE at 175C, water flow rate of 2 g/min and mean particle size of 0.5 mm were found to be able to recover 3.82% (w/w) of caffeine present in the black tea leaf within 3 h of extraction. In comparison to the SCWE, conventional hot water extraction showed 3.30% (w/w) extraction yield. It was found also that pressure had no effect on extraction yield and rate. PRACTICAL APPLICATIONS Recently, subcritical water has become of great interest as an alternative solvent for extraction of natural active compounds. Subcritical water, as a green solvent, can be used in many different fields of applications. In recent years, extraction of flavors, fragrances and antioxidant components from plant materials, and hydrolysis of carbohydrates, vegetable oils and fatty acids have been widely investigated by many researchers. Using subcritical water for analytical purposes, for soil remediation and applying it as a reaction media are some other interesting fields for practical applications. Subcritical water is an excellent solvent for caffeine as well as many other organic compounds but is safer than the organic solvents that are used for caffeine extraction. [source]

Genetic Analysis of ele Mutants and Comparative Mapping of ele1 Locus in the Control of Organ Internal Asymmetry in Garden Pea

JOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 6 2010
Xin Li
Previous study has shown that during zygomorphic development in garden pea (Pisum sativum L.), the organ internal (IN) asymmetry of lateral and ventral petals was regulated by a genetic locus, SYMMETRIC PETAL 1 (SYP1), while the dorsoventral (DV) asymmetry was determined by two CYC - like TCP genes or the PsCYC genes, KEELED WINGS (K) and LOBED STANDARD 1 (LST1). In this study, two novel loci, ELEPHANT EAR-LIKE LEAF 1 (ELE1) and ELE2 were characterized. These mutants exhibit a similar defect of IN asymmetry as syp1 in lateral and ventral petals, but also display pleiotropic effects of enlarged organ size. Genetic analysis showed that ELE1 and ELE2 were involved in same genetic pathway and the enlarged size of petals but not compound leaves in ele2 was suppressed by introducing k and lst1, indicating that the enlargement of dorsal petal in ele2 requires the activities of K and LST1. An experimental framework of comparative genomic mapping approach was set up to map and clone LjELE1 locus in Lotus japonicus. Cloning the ELE1 gene will shed light on the underlying molecular mechanism during zygomorphic development and further provide the molecular basis for genetic improvement on legume crops. [source]

CHRACTERIZATION AND 1,1-DIPHENYL-2-PICRYLHYDRAZYL RADICAL SCAVENGING ACTIVITY OF METHANOL AND SUPERCRITICAL CARBON DIOXIDE EXTRACTS FROM LEAVES OF ADINANDRA NITIDA

JOURNAL OF FOOD BIOCHEMISTRY, Issue 4 2008
BENGUO LIU
ABSTRACT Leaves of Adinandra nitida are consumed in southern China as health tea (Shiyacha) and as herbal medicine. In this study, the methanol and supercritical fluid extracts from leaves of A. nitida were obtained by traditional solvent extraction and supercritical carbon dioxide extraction, respectively. Both the extracts showed high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. By using ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), nuclear magnetic resonance, electrospray ionization mass spectrometry (ESI-MS), high-performance liquid chromatography-ESI/MS, the main bioactive constituents in the methanol extract (ME) were identified as camellianin A, camellianin B, apigenin. By analysis of gas chromatography-mass spectrometry, a total of 16 compounds accounting for 98.79% of the supercritical fluid extract (SFE) were identified as ,-sitosterol, vitamin E, ,-tocopherol and so on. These compounds found in ME and SFE could contribute to the DPPH radical scavenging performance of the extracts in this study. PRACTICAL APPLICATION Adinandra nitida is a kind of particular wild plant in South China. Few reports have been published about it in the world. In this study, the methanol and supercritical fluid extracts from leaves of A. nitida were respectively obtained by two kinds of industrially significant methods, traditional solvent extraction and supercritical carbon dioxide extraction. By using ultraviolet-visible spectrometry (UV), infrared spectrometry (IR), nuclear magnetic resonance, electrospray ionization mass spectrometry (ESI-MS), high-performance liquid chromatography-ESI/MS, gas chromatography-MS, the main bioactive constituents in the two extracts were identified as flavonoids and plant sterols. Both the extracts showed high 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and this activity of the flavonoid-rich methanol extract was 10 times more than that of butylated hydroxytoluene. These results showed that leaves of A. nitida is a new kind of natural antioxidant-rich, flavonoid-rich plant source with great commercial interest in the food and phytopharmaceutical market. [source]

CYSTATIN ACCUMULATION IN TOMATO LEAVES AFTER METHYL JASMONATE TREATMENT OR MECHANICAL INJURY

JOURNAL OF FOOD BIOCHEMISTRY, Issue 1 2002
JU WEN WU
The elicitation of cystatin accumulation in tomato leaves was studied with mature and seedling cv. Bonnie Best. Repetitive mechanical injury (MI) or methyl jasmonate (MJ) treatment of seedlings elicited plentiful cystatin accumulation in the leaves when plants were held at 30C under continuous lighting. Cystatin accumulation in leaves of MI seedlings decreased by 50% when incubated at a reduced light period of 12 h light/day. Cystatin accumulation in MJ treated plants was not influenced by reducing the light period from 24 h to 12 h/day. Cystatin accumulation after MJ treatment was optimal at 35C and negligible at 40C. At ambient field conditions (I8,33C), MJ treated seedlings still accumulated a significant amount of cystatin; however, very little cystatin accumulated in leaves of MI seedlings under these conditions of lower temperature and light exposure. The leaves of mature plants accumulated less cystatin after MJ or MI treatment than did those of seedlings. [source]

EVALUATION OF GLOBAL YIELD, COMPOSITION, ANTIOXIDANT ACTIVITY AND COST OF MANUFACTURING OF EXTRACTS FROM LEMON VERBENA (ALOYSIA TRIPHYLLA[L'HÉRIT.] BRITTON) AND MANGO (MANGIFERA INDICA L.) LEAVES

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2007
CAMILA G. PEREIRA
ABSTRACT In this work, the global yields, composition and antioxidant activity (AA) of extracts from lemon verbena (Aloysia triphylla) and mango (Mangifera indica) leaves obtained by different separation processes were determined. Lemon verbena extracts were obtained by supercritical fluid extraction (SFE), while mango leaf extracts were obtained by SFE, low-pressure solvent extraction (LPSE) and hydrodistillation. The extract's constituents were analyzed by thin-layer chromatography, gas chromatography/mass spectrometry and gas chromatography/flame ionization detector. The AA of the extracts was evaluated by the coupled reaction of , -carotene/linolenic acid. The cost of manufacturing (COM) was estimated for the SFE extracts. Higher global yields were obtained using SFE at 350 bar/45C (1.49%) for lemon verbena and LPSE (3.04%) for mango. The AAs of the extracts were larger than that of the , -carotene for both plants. The minimum values of COM were U.S.$26.96 and 52.45/kg of extract for lemon verbena and mango, respectively. [source]

SUPERHEATED STEAM-DRYING OF MATE LEAVES AND EFFECT OF DRYING CONDITIONS ON THE PHENOL CONTENT

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 3 2006
EVERTON FERNANDO ZANOELO
ABSTRACT Four drying experiments of mate leaves (Ilex paraguariensis St. Hilaire) were carried out in a packed bed superheated steam dryer by varying outlet steam temperature from 120 to 140C and equivalent particle diameter from 4.7 × 10,3 to 6.95 × 10,3 m. The influence of these variables on the drying coefficient calculated by assuming a simplified drying kinetic model was investigated. A classical statistical approach revealed the significant effect of both factors on this parameter. Two additional drying runs were performed at identical conditions with conventional hot air and low pressure superheated steam, respectively. The influence of drying atmosphere on the total content of phenols was evaluated. A conventional process of extraction by using an aqueous methanol solution was adopted. Analyses for total phenols were performed by spectrophotometry at 715 nm by applying Folin-Denis assay. The leaves dried with superheated steam had approximately 47% higher retention of these compounds. [source]

EFFECT OF DIRECT APPLICATIONS OF SAGE (SALVIA OFFICINALIS L.) LEAVES ON OXIDATIVE STABILITY OF SUNFLOWER OIL DURING ACCELERATED STORAGE

JOURNAL OF FOOD QUALITY, Issue 5 2009
EDA ÇALIKO
ABSTRACT In this study, various sage applications were examined on oxidative stability of sunflower oil during accelerated storage. There are three applications: (1) direct sage leaves (S); (2) deodorized sage leaves (DeS); and (3) essential oil of sage leaves. The main compounds of essential oil were identified as, -thujone (35.87%),, -thujone (14.41%), 1,8-cineol (10.59%) and camphor (10.09%). Oxidative stability of these three applications was tested by Schall Oven test at 60C applying peroxide value and conjugated dienes, and Rancimat at 110C. Whereas the highest antioxidants activity was found for 2% S followed by 0.5% S and 2% DeS, all sage treatments statistically retarded the oxidation compared with the control sample. The most appealing result was that the residue can be used as a natural antioxidants. That means the reuse of residue may decrease economic losses and health risk in comparison with synthetic antioxidants and extracts because it is completely natural and contains no residual solvent. PRACTICAL APPLICATIONS While almost all of previous studies were concentrated on the use of herb extracts, our study investigates the results of direct application of sage on oxidation. Especially with this study, we have evaluated a possible application area for sage residue leftover after the deodorization process. [source]

INTRAMARGINAL VEINED LAURACEAE LEAVES FROM THE ALBIAN,CENOMANIAN OF CHARENTE-MARITIME (WESTERN FRANCE)

PALAEONTOLOGY, Issue 2 2009
CLÉMENT COIFFARD
Abstract:,Eucalyptolaurus depreii gen. et sp. nov. is proposed for angiosperm leaves newly collected from uppermost Albian , lowermost Cenomanian of Charente-Maritime (western France). They consist of simple, narrow, elongate laminas with entire margins and intramarginal veins. The epidermal cells of adaxial cuticle shows small, rounded, blunt papillae outward that protrude inward and fuse together as rolls along and parallel to the margins, while the adaxial cuticle bears brachyparacytic stomatal apparatus that exhibit sunken guard cells and hair bases consisting of a thick-walled pore surrounded by radially arranged differentiated cells. Resin bodies occur inside the mesophyll. These characters closely resemble the lauroid taxa ,Myrtophyllum' and Pandemophyllum from the Cenomanian of the Czech Republic and Dakota (USA) respectively. The narrow angle of basilaminar secondaries and the whole suite of features in the guard cells (sunken guard cells embedded into subsidiary cells and stomatal ledges) strongly support close affinity with the Lauraceae. From the Cenomanian lauraceous reproductive organs and their related leaves already showed high disparity and diversity. In addition they displayed a broad ecological range from freshwater floodplains to brackish swamps. This combined to high diversity of reproductive organs suggest ecological radiation of Lauraceae by the Cenomanian. [source]

DOMINO1, a member of a small plant-specific gene family, encodes a protein essential for nuclear and nucleolar functions

THE PLANT JOURNAL, Issue 6 2004
Sylvie Lahmy
Summary Arabidopsis embryos carrying the domino1 mutation grow slowly in comparison with wild type embryos and as a consequence reach only the globular stage at desiccation. The primary defect of the mutation at the cellular level is the large size of the nucleolus that can be observed soon after fertilization in the nuclei of both the embryo and the endosperm. The ultrastructure of mutant nucleoli is drastically different from wild type and points to a fault in ribosome biogenesis. DOMINO1 encodes a protein, which belongs to a plant-specific gene family sharing a common motif of unknown function, present in the tomato DEFECTIVE CHLOROPLASTS AND LEAVES (LeDCL) protein. Using a GFP protein fusion, we show that DOMINO1 is targeted to the nucleus. We propose that inactivation of DOMINO1 has a negative effect on ribosome biogenesis and on the rate of cell division. [source]

Leaf Processing by Wild Chimpanzees: Physically Defended Leaves Reveal Complex Manual Skills

ETHOLOGY, Issue 8 2002
Nadia Corp
The manual processing of eight species of leaf was investigated in the M-group chimpanzees of Mahale Mountains National Park, Tanzania. Leaf species varied in the extent to which physical defences made consumption difficult. In all, 96 distinct techniques for leaf processing were identified, but two species with defended leaves (Ficus asperifolia and F. exasperata) required 2.5 as many techniques as did any of the six undefended species. Moreover, chimpanzees made more multiple leaf detachments, and made more subsequent modifications of the leaves, when dealing with the leaves of these two Ficus species, compared with the undefended leaf species. This greater complexity was associated with evidence of flexible, hierarchical organization of the process: iteration of modules consisting of several processing elements, facultative omission of modules, or substitutions of alternative modules. Comparison with data from mountain gorillas is made, and is consistent with similar cognitive architecture in the two species. We consider that, not only is hierarchical organization currently associated with mechanical difficulty in food processing, but that over evolutionary time-scales difficulties in food processing may have selected for cognitive advance. [source]

Chemical variability of the leaf oil of 113 hybrids from Citrus clementina (Commun) × Citrus deliciosa (Willow Leaf)

FLAVOUR AND FRAGRANCE JOURNAL, Issue 3 2008
Félix Tomi
Abstract Essential oils of 113 Citrus clementina (Commun) × Citrus deliciosa (Willow Leaf) hybrids were obtained from leaves collected on trees located in the same orchard. Their chemical composition was investigated by capillary GC, GC,MS and 13C-NMR and the results were submitted to statistical analysis. Three chemical compositions were characterized. The crossing between clementine and mandarin produces mainly leaf oils characterized by a composition similar to those of the parents (sabinene/linalool or methyl N-methylanthranylate). However, several samples exhibited an original composition (,- terpinene/linalool). Copyright © 2008 John Wiley & Sons, Ltd. [source]

Leaf and peel volatile compounds of an interspecific citrus somatic hybrid [Citrus aurantifolia (Christm.) Swing. + Citrus paradisi Macfayden]

FLAVOUR AND FRAGRANCE JOURNAL, Issue 6 2002
Anne-Laure Gancel
Abstract The volatile compounds from leaves and peels of an interspecific citrus somatic hybrid, Citrus aurantifolia (Christm.) Swing. + Citrus paradisi Macfayden, obtained by fusion of protoplasts from lime, Citrus aurantifolia (cv. Mexican Lime) and grapefruit, Citrus paradisi (cv. Star Ruby), were extracted by pentane : ether (1 : 1) from liquid nitrogen ball-milled leaves and flavedo and examined by GC,MS in comparison to those of its parents. The hybrid quantitatively retained the ability of the lime parent to synthesize in its leaves the major monoterpene aldehydes (neral, geranial) the monoterpene alcohols (nerol, geraniol), and their acetates, and also the capacity of the grapefruit parent to produce a sesquiterpene aldehyde (,-sinensal) in its leaves and nootkatone in its peel. Conversely, synthesis of most sesquiterpene hydrocarbons and long chain aliphatic aldehydes, which are present in the lime parent leaves and peel, was strongly inhibited in the hybrid, as in the grapefruit parent. In comparison to its parents, the hybrid overproduced citronellal in its leaves and ,-sinensal and ,-sinensal in its peel. Based on these results, the future prospects for a better understanding of the inheritance mechanisms with regards to aroma biosynthesis in citrus leaves and peels are discussed. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Modelling canopy CO2 fluxes: are ,big-leaf' simplifications justified?

GLOBAL ECOLOGY, Issue 6 2001
A. D. Friend
Abstract 1The ,big-leaf' approach to calculating the carbon balance of plant canopies is evaluated for inclusion in the ETEMA model framework. This approach assumes that canopy carbon fluxes have the same relative responses to the environment as any single leaf, and that the scaling from leaf to canopy is therefore linear. 2A series of model simulations was performed with two models of leaf photosynthesis, three distributions of canopy nitrogen, and two levels of canopy radiation detail. Leaf- and canopy-level responses to light and nitrogen, both as instantaneous rates and daily integrals, are presented. 3Observed leaf nitrogen contents of unshaded leaves are over 40% lower than the big-leaf approach requires. Scaling from these leaves to the canopy using the big-leaf approach may underestimate canopy photosynthesis by ~20%. A leaf photosynthesis model that treats within-leaf light extinction displays characteristics that contradict the big-leaf theory. Observed distributions of canopy nitrogen are closer to those required to optimize this model than the homogeneous model used in the big-leaf approach. 4It is theoretically consistent to use the big-leaf approach with the homogeneous photosynthesis model to estimate canopy carbon fluxes if canopy nitrogen and leaf area are known and if the distribution of nitrogen is assumed optimal. However, real nitrogen profiles are not optimal for this photosynthesis model, and caution is necessary in using the big-leaf approach to scale satellite estimates of leaf physiology to canopies. Accurate prediction of canopy carbon fluxes requires canopy nitrogen, leaf area, declining nitrogen with canopy depth, the heterogeneous model of leaf photosynthesis and the separation of sunlit and shaded leaves. The exact nitrogen profile is not critical, but realistic distributions can be predicted using a simple model of canopy nitrogen allocation. [source]

Are more productive varieties of Paspalum dilatatum less tolerant to drought?

GRASS & FORAGE SCIENCE, Issue 3 2010
L. L. Couso
Abstract Paspalum dilatatum Poir., is a perennial C4 grass widely distributed in the Argentinean Pampas. The response to water availability for materials developed with forage-production purposes is unknown. We hypothesized that genetic differences between commercial varieties are reflected in their regrowth capacity under water stress. The effect of five levels of constant water supply on three plant varieties (two derived from apomictic materials: ,Relincho' and ,Alonso' and one from sexually-derived material: ,Primo') were examined in the greenhouse. Leaf- and plant-response traits were followed during 38 d after a single defoliation event. Seven response variables were measured: three of them were morphogenetic (leaf elongation rate, leaf appearance rate and leaf elongation duration) and four were structural (number of live leaves, lamina length, tiller biomass and tiller production). The sexual material showed higher values for growth variables than the apomictic varieties (leaf elongation rate, leaf length and tiller biomass) across the environmental range. Apomictic varieties showed a proportionally similar drought response to the sexual material for the seven variables. No intra-specific trade-off (statistical interaction) was found between growth under high water availability conditions and drought tolerance. [source]

Nanoporous Gold Leaf: "Ancient Technology"/Advanced Material,

ADVANCED MATERIALS, Issue 21 2004
Y. Ding
A free-standing nanoporous gold (NPG) membrane is made by dealloying commercially available white-gold leaf in nitric acid (see Figure). This porous material has an unusual combination of characteristics in that it is metallic with a continuous crystal lattice throughout the porous network, and has a pore size that is adjustable via simple room-temperature post-processing. This ultra-high-surface-area material is potentially very useful for applications such as electrocatalysis and sensing. [source]

Leaf Associated Microbial Activities in a Stream Affected by Acid Mine Drainage

INTERNATIONAL REVIEW OF HYDROBIOLOGY, Issue 5-6 2004
Jeanette SchliefArticle first published online: 23 NOV 200
Abstract Microbial activity was assessed on birch leaves and plastic strips during 140 days of exposure at three sites in an acidic stream of the Lusatian post-mining landscape, Germany. The sites differed in their degrees of ochre deposition and acidification. The aim of the study was (1) to follow the microbial activities during leaf colonization, (2) to compare the effect of different environmental conditions on leaf associated microbial activities, and (3) to test the microbial availability of leaf litter in acidic mining waters. The activity peaked after 49 days and subsequently decreased gradually at all sites. A formation of iron plaques on leaf surfaces influenced associated microbial activity. It seemed that these plaques inhibit the microbial availability of leaf litter and serve as a microbial habitat by itself. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Response of Photosynthesis and Water Relations of Rice (Oryza sativa) to Elevated Atmospheric Carbon Dioxide in the Subhumid Zone of Sri Lanka

JOURNAL OF AGRONOMY AND CROP SCIENCE, Issue 2 2003
W. A. J. M. De Costa
Abstract The objective of the present paper is to determine the response of the physiological parameters related to biomass production and plant water relations in a standard Sri Lankan rice (Oryza sativa) variety (BG-300) to elevated CO2 (i.e. 570 µmol/mol). During two seasons, rice crops were grown under three different experimental treatments; namely, at 570 µmol/mol (i.e. ,elevated') and 370 µmol/mol (,ambient') CO2 within open top chambers, and at ambient CO2 under open field conditions. Leaf net photosynthetic rate in the elevated treatment increased by 22,75 % in comparison to the ambient. However, the ratio between intercellular and ambient CO2 concentrations remained constant across different CO2 treatments and seasons. CO2 enrichment decreased individual leaf stomatal conductance and transpiration rate per unit leaf area, and increased both leaf and canopy temperatures. However, the overall canopy stomatal conductance and daily total canopy transpiration rate of the elevated treatment were approximately the same as those achieved under ambient conditions. This was because of the significantly greater leaf area index and greater leaf,air vapour pressure deficit under CO2 enrichment. The leaf chlorophyll content increased significantly under elevated CO2; however, the efficiency (i.e. photochemical yield) of light energy capture by Photosystem II (i.e. Fv/Fm) in chlorophyll a did not show a significant and consistent variation with CO2 enrichment. [source]

Effect of Maturity Stages and Drying Methods on the Retention of Selected Nutrients and Phytochemicals in Bitter Melon (Momordica charantia) Leaf

JOURNAL OF FOOD SCIENCE, Issue 6 2009
Min Zhang
ABSTRACT:, The purpose of this study was to investigate the nutrient and phytochemical composition of bitter melon leaves under varying maturity levels and drying techniques. Fresh, oven-dried, and freeze-dried leaves were evaluated over 3 maturity stages. In fresh leaves at various stages, crude fat, crude protein, and soluble dietary fiber contents ranged from 4.2% to 13.6%, 6.4% to 23.1%, and 0.04% to 3.50% on dry-weight basis, respectively. The contents of K, Ca, Mg, Fe, and Zn ranged from 1850.8 to 2811.8, 837.4 to 4978.2, 317.3 to 512.4, 8.4 to 16.7, and 4.1 to 5.9 mg/100 g dry-weight basis, respectively. Vitamin C, ,-carotene, and lutein contents ranged from 397.4 to 1275.1, 154.2 to 422.8, and 737.6 to 1304.6 ,g/g dry-weight basis. The major flavonoids and phenolic acids were rutin, gentistic acid, and,o -coumaric acid, which ranged from 7.57 to 12.75, 2.53 to 10.11, and 4.24 to 9.75 mg/g dry-weight basis, respectively. In oven-dried samples, 40.2% to 52.3% of vitamin C, 35.4% to 55.4% of ,-carotene, 25.6% to 71.6% of lutein, 26.4% to 84.0% of rutin, trace to 11.4% of gentistic acid, and 7.4% to 46.6% of,o -coumaric acid were retained, while the retainment ratios of these components in freeze-dried samples were 84.7% to 99.0%, 76.4% to 99.3%, 90.4% to 96.1%, 39.8% to 99.3%, 24.1% to 68.4%, and 75.8% to 87.0%, respectively. The data showed that freeze-drying better preserves the nutrient and phytochemical quality of bitter melon leaves in comparison to oven-drying. Bitter melon leaf is a rich source of selected nutrients and phytochemicals. [source]

Genetic Mapping of Magnaporthe grisea Avirulence Gene Corresponding to Leaf and Panicle Blast Resistant QTLs in Jao Hom Nin Rice Cultivar

JOURNAL OF PHYTOPATHOLOGY, Issue 6 2009
Tanee Sreewongchai
Abstract The avirulence characteristic of Magnaporthe grisea isolate TH16 corresponding to Jao Hom Nin (JHN) rice cultivar was studied by mapping population of 140 random ascospore progenies derived from the cross between B1-2 and TH16 isolates. Segregation analyses of the avirulence characteristic performing on JHN rice at the seedling and flowering stages were performed in this mapping population. We used the reference map of Guy11/2539 to choose microsatellite DNA markers for mapping the avirulence gene. The genetic map of this population was constructed from 39-microsatellite markers. The genetic map was spanned by covering seven chromosomes with an average distance of 11.9 cM per marker. In mapping population the distribution of pathogenic and non-pathogenic progenies on JHN rice were found to be fitted to 1 : 1 ratio for two of the rice stages, seedling and flowering stages. The Quantitative Trait Loci (QTL) analysis for avirulence genes corresponding to two rice stages were located at the same region on chromosome 2 between markers Pyms305 and Pyms435. The LOD score and percentage of phenotypic variance explained (PVE) on two rice stages were 5.01/16.69 and 6.73/20.26, respectively. These loci were designated as Avr-JHN(lb) and Avr-JHN(pb) corresponding to leaf and panicle blast characteristics. The findings of this study can be the initial step for positional cloning and identifying any function of avirulence genes corresponding to leaf and panicle blast characteristics. [source]

Immunolocalization and Histocytopathological Effects of Xanthomonas arboricola pv. pruni on Naturally Infected Leaf and Fruit Tissues of Peach (Prunus persica L. Batsch)

JOURNAL OF PHYTOPATHOLOGY, Issue 6 2008
J. Aarrouf
Abstract Immunofluorescence and cytohistochemical studies have been performed to understand the host,parasite relationships in the pathosystem: peach,Xanthomonas arboricola pv. pruni (Xap). Using a commercial immunodetection kit, Xap cells were specifically identified in tissues from infected leaves and fruits. Sections from infected leaves showed that the pathogen penetrates the mesophyll via stomata and develops in the intercellular spaces where it degrades the cell wall components. This leads to cell collapse and consequently to the formation of necrotic lesions. The same events have been noted in sections from infected fruits. However, the contaminated zones of mesocarp parenchyma exhibited cell dedifferentiation and generated somatic embryo-like structures. Sections from midrib samples collected at different distances from infected lamina revealed the presence of Xap cells in the sieve tubes and xylem suggesting a systemic trafficking of the pathogen. The results are discussed in terms of cytological effects and epidemiology of Xap. [source]

Components of Partial Disease Resistance in Wheat Detected in a Detached Leaf Assay Inoculated with Microdochium majus using First, Second and Third Expanding Seedling Leaves

JOURNAL OF PHYTOPATHOLOGY, Issue 4 2006
R. A. Browne
Abstract The use of first, second and third expanding seedling leaves of wheat (L1, L2 and L3 respectively), inoculated with conidial suspensions of Microdochium majus (syn. Microdochium nivale var. majus) in a detached leaf assay, for detecting components of partial disease resistance (PDR) was investigated across a range of wheat cultivars. Incubation periods (period from inoculation to first appearance of symptoms; a dull grey,green water-soaked lesion) and latent periods (period from inoculation to the first appearance of sporodochia) were longest and lesions smallest on L3. The expression of PDR components on L2 was intermediate to those on L1 and L3. The longer latent periods on L3 typically occurred after leaf senescence contrasting with latent periods on L1 and L2 where sporulation most frequently occurred on relatively green leaf tissue. Cultivar differences in the first appearance of symptoms, incubation period, which occurred before any leaf senescence was observed, correlated significantly across all leaf positions. Similarly cultivar differences in latent period were correlated for L1 and L2. However, latent periods on L3, which were the least consistent between cultivars across experiments, were not correlated with those of L1 or L2 in any experiment. The results indicate that due to the delay in sporulation until after leaf senescence, observations on latent period in L3 are less representative of what occurs in the whole plant where infection of living tissue is of greatest interest. This work indicates that the selection of the first or second expanding leaf of wheat is optimal for the use in the detached leaf assay using M. majus for studying components of PDR. [source]

Osmoprotectant , -alanine betaine synthesis in the Plumbaginaceae: S -adenosyl- l -methionine dependent N -methylation of , -alanine to its betaine is via N -methyl and N,N -dimethyl , -alanines

PHYSIOLOGIA PLANTARUM, Issue 3 2000
Bala Rathinasabapathi
, -Alanine betaine is an osmoprotective compound accumulated by most members of the plant family Plumbaginaceae. Leaf and root tissues of Limonium latifolium known to accumulate , -alanine betaine readily convert supplied , -alanine to , -alanine betaine. To identify the intermediates and the enzymes involved in , -alanine betaine synthesis, radiotracer experiments using [ C] formate were employed. These studies demonstrate that , -alanine betaine is synthesized from , -alanine via N -methyl and N,N- dimethyl , -alanines. A rapid and sensitive radiometric assay was developed to measure N -methyltransferase (NMT) activities by using [methyl- 14C] or [methyl- 3H] S -adenosyl- l -methionine (AdoMet) as the methyl donor. Leaf extracts from , -alanine betaine accumulators ,Armeria maritima, L. latifolium and L. ramosissimum, had detectable NMT activities while none were found in L. perezii, a species that does not accumulate , -alanine betaine. The NMT activities were further characterized from the leaves of L. latifolium. The activities had a pH optimum of 8.0, were soluble and inhibited by S -adenosyl- l -homocysteine. Extractable activities were similar from plants grown under control and salinity stress conditions. Radiolabeling with [ C] l -aspartic acid indicated that, unlike in bacteria, decarboxylation of l -aspartic acid is not the source of , -alanine in the Plumbaginaceae. [source]

Leaf, floret and seed infection of wheat by Pyrenophora semeniperda

PLANT PATHOLOGY, Issue 4 2003
M. A. Campbell
Infection processes of Pyrenophora semeniperda on seedling and adult wheat leaves and wheat ears were investigated. Almost 100% germination of conidia occurred on seedling leaves, compared with 20,30% on adult leaves. Appressoria formed over the anticlinal epidermal cell walls and haloes always accompanied infection. Sometimes papillae formed within the leaves as a resistance mechanism. Infection hyphae ramified through the intercellular spaces of the mesophyll resulting in cellular disruption. The infection processes on floral tissues were similar to those observed on leaves; however, no infection occurred on anther, stigmatic or stylar tissues. Infection of ovarian tissue occurred both with and without appressoria formation. Hyphae grew mainly in the epidermal layers and appeared unable to breach the integumental layer as no growth was observed in endosperm or embryo tissues. The optimum dew period temperature for conidial germination was 23·6°C, compared with 19·9°C for lesion development, 20·4°C for the production of infection structures on seedling leaves and 23·7°C for floret infection. Leaf disease development occurred in a logistic manner in response to dew period, with maximum infection observed after 21 h compared with > 48 h in seeds. An initial dark phase during the dew period was necessary for infection and temperature after the dew period had an effect, with significantly more numerous and larger lesions being formed at 15°C compared with 30°C. Seedling leaves were found to be more susceptible than older leaves, under both field and controlled environment conditions. Infection of wheat seeds following inoculation of ears, or after harvest burial of inoculated disease-free seeds, was demonstrated. In the latter, 3-week-old seedlings were slightly stunted, whereas older plants were unaffected. The apparent unimportance of this plant pathogen as a cause of leaf disease in relation to its poor adaptation to dew periods and dew period temperature is discussed, along with the importance of its seed borne characteristics. [source]

Influences of Northern Leaf Blight on corn silage fermentation quality, nutritive value and feed intake by sheep

ANIMAL SCIENCE JOURNAL, Issue 4 2010
Peng WANG
ABSTRACT This study examined the differences between non-inoculated (control) corn and Northern Leaf Blight (NLB)-damaged corn (inoculated corn); dry matter (DM) yield, silage fermentation quality, nutritive value and feed intake by sheep were compared. Leaf, stem and grain dry weights and gross yield of inoculated corn were significantly (P < 0.05) decreased compared with control corn. The contents of water-soluble carbohydrate and nitrogen-free extract (NFE) were decreased in inoculated corn compared with control corn. Silage made from both inoculated and control corn showed good fermentation quality. The digestibility of DM, organic matter, ether extract, NFE, and energy of silage made from inoculated corn were significantly (P < 0.05) lower, and contents of total digestible nutrients (TDN) and digestible energy (DE) were also significantly (P < 0.05) lower compared with silage made from the control corn. DM intake showed no significant discrepancy between the two types of silage. TDN and DE intakes from inoculated silage were significantly (P < 0.05) lower compared with control silage. From the above results it was shown that NLB caused a decrease in DM yield and NFE content in corn and a decrease in the nutritive value and feed intake of silage. [source]

Protein Fractionation of Cowpea (Vigna unguiculata (L.) Walp) Leaf, Flower and Seed by Capillary Electrophoresis and Its Potential for Variety Identification

CHINESE JOURNAL OF CHEMISTRY, Issue 4 2010
Sirithon Siriamornpun
Abstract The proteins of different faction of cowpea [Vigna unguiculata (L.) Walp] were fractionated by capillary electrophoresis (CE). The extracting solvent system was one of the most critical factors in the optimization exercise. To improve reproducibility, seed samples needed to be defatted with chloroform/methanol (V:V=2:1) as preferred prior to protein extraction. Proteins were extracted from seeds, leaves and flowers with 50% aqueous 1-propanol and separated on a 50 (m×20 cm fused silica capillary column using a UV detector at 200 nm. Separation was conducted at constant voltage (10 kV, 40°C), using iminodiacetic acid (pH 2.5) containing 0.05% hydroxypropylmethylcellulose (HPMC) and 20% acetonitile. The results showed that proteins extracted from all fraction of cowpea were successfully separated by CE in less than 20 min. Seed extracts provided the greatest number of eluted protein peaks, followed by flower and leaf, respectively. The seed-protein extracts provided unique CE patterns for different varieties; hence the seed was the tissue chosen as being most suitable for variety identification. As a result, an optimized procedure was developed to provide rapid identification of cowpea varieties, based on capillary electrophoregram patterns. [source]

Accumulation and solubility of metals during leaf litter decomposition in non-polluted and polluted soil

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 4 2009
S. Scheid
Summary The decomposition of alder (Alnus glutinosa) and poplar (Populus tremula) leaf litter placed in direct contact with non-polluted and metal-polluted soil was investigated over 25 months in a controlled model-ecosystem experiment using the litterbag method. In addition to mass loss, we monitored the total and soluble concentrations of carbon, Cu, Zn, Cd and Pb. Leaves from trees grown on polluted soil had larger initial Zn, Cd and dissolved organic carbon concentrations. Neither the origin of the leaves (from trees grown on non-polluted or polluted soil) nor the placement of the leaves in polluted or unpolluted soil affected the decomposition process. Total metal contents increased in leaves placed on polluted soil over time. The solubility of metals in the leaf litter decreased over time, indicating that leaves acted as a temporary pool for metals from the soil in direct contact with the leaves. The sorbed metals were strongly bound in the litter even after two years of decomposition. The strong binding and thus reduced bioavailability of the metals provides an explanation for why they had no observable effects on litter decomposition. [source]

The End of an Era: Lyman Wynne Leaves the Family Process Board of Directors

FAMILY PROCESS, Issue 1 2000
Robert G. Ryder President
No abstract is available for this article. [source]

Leaf fungi of two wild plants in Assiut, Egypt

FEDDES REPERTORIUM, Issue 7-8 2004
S. K. Hemida
Leaves of two wild species of the flora of Egypt: Calotropis procera (Ait.) Ait., Asclepiadaceae and Chrozophora plicata (Vahl) A.Juss. ex Spreng., Euphorbiaceae have been studied morphologically and mycologically, in addtion to air borne fungi. Fifty five species and two varieties belonging to 26 genera of phyllosphere and phylloplane fungi were isolated from both plant species on glucose- and cellulose-agar media. Mycological analysis was done monthly over six months (July to December, 2003). Alternariaalternata, Aspergillus fumigatus, A. flavus and A. niger were the basic fungal species found on leaf surfaces. Phylloplane of C. plicata caught specifically Chaetomiumglobosum, C.,spirale, Cochliobolus lunatus, Drechslera halodes, Fusarium incarnatum, F. oxysporum, Memnoniella echinata and Papulaspora sepedonioides. The total counts of phyllosphere fungi of C.,plicata were nearly twice as much as those of C.,procera regardless medium's type. Forty species and one variety belonging to 22 genera of air borne fungi were recovered all over the experimental period (six months). Alternaria, Aspergillus, Cladosporium and Penicillium were the most frequently isolated species. The presented results revealed that, leaf shape and density (hair density and type) may be the most important factors of the biodiversity of the fungal species on the studied taxa. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Die Blätter zweier Wildarten aus der Flora Ägyptens: Calotropis procera (Ait.) Ait., Asclepiadeceae, und Chrozophora plicata(Vahl) A.Juss. ex Spreng., Euphorbiaceae, wurden in Bezug auf ihre Morphologie und Mykologie untersucht sowie zusätzlich auf ihre "luftgeborenen" Pilze. Auf beiden Arten wurden auf einem Glukose- bzw. Cellulose-Medium insgesamt 55 Arten und zwei Varietäten aus 26 Gattungen phyllosphärer und phylloplaner Pilze nachgewiesen. Die mykologischen Analysen wurden über einen Zeitraum von sechs Monaten (Juli bis Dezember 2003) durchgeführt. Alternariaalternata, Aspergillus fumigatus, A. flavus und A. niger waren die Basis-Pilzarten, die auf den Blattoberflächen ermittelt wurden. Auf C. plicata waren Chaetomiumglobosum, C. spirale, Cochliobolus lunatus, Drechslera halodes, Fusarium incarnatum, F. oxysporum, Memnoniella echinata und Papulaspora sepedonioides die häufigsten phylloplanen Arten. Ungeachtet des Mediumtyps war die Anzahl phyllosphärischer Pilze auf C. plicata etwa zweimal so hoch wie auf C. procera. Über die gesamte Versuchszeit von sechs Monaten wurden 40 Arten und eine Varietät aus 22 Gattungen "luftgeborener" Pilze beobachtet. Mit Alternaria, Aspergillus, Cladosporium und Penicillium fanden sich die am häufigsten isolierten Arten. Aus den erzielten Ergebnissen kann man ableiten, dass Blattform und Haare (Dichte und Typ) die wichtigsten Faktoren für die Biodiversität der untersuchten Pilzarten sind. [source]

Colonization of beech leaves by two endophytic fungi in northern Japan

FOREST PATHOLOGY, Issue 2 2000
N. Sahashi
Summary Leaves of Japanese beech (Fagus crenata) were collected monthly during the vegetation period at five sites in the Tohoku district in Japan to isolate endophytic fungi. Leaves were also collected only once at two additional sites. Two endophytic fungi were dominant, a Discula species and a sterile mycelium. This result strongly suggests that these two fungi are generally associated with leaves of the Japanese beech at different sites. At most sites the isolation frequency of Discula sp. was greatest in June and gradually decreased from July to October whereas the isolation frequency of the sterile mycelium increased during the vegetation period and remained at a high isolation frequency in October. Spores of Discula sp. were released for a very short time in late May, just after the disappearance of the snow cover on the forest floor. These spores may be important for the infection of newly sprouting leaves. [source]

Interactions between fauna and sediment control the breakdown of plant matter in river sediments

FRESHWATER BIOLOGY, Issue 4 2010
SIMON NAVEL
Summary 1. A substantial portion of particulate organic matter (POM) is stored in the sediment of rivers and streams. Leaf litter breakdown as an ecosystem process mediated by microorganisms and invertebrates is well documented in surface waters. In contrast, this process and especially the implication for invertebrates in subsurface environments remain poorly studied. 2. In the hyporheic zone, sediment grain size distribution exerts a strong influence on hydrodynamics and habitability for invertebrates. We expected that the influence of shredders on organic matter breakdown in river sediments would be influenced strongly by the physical structure of the interstitial habitat. 3. To test this hypothesis, the influence of gammarids (shredders commonly encountered in the hyporheos) on degradation of buried leaf litter was measured in experimental systems (slow filtration columns). We manipulated the structure of the sedimentary habitat by addition of sand to a gravel-based sediment column to reproduce three conditions of accessible pore volume. Ten gammarids were introduced in columns together with litter bags containing alder leaves at a depth of 8 cm in sediment. Leaves were collected after 28 days to determine leaf mass loss and associated microbial activity (fungal biomass, bacterial abundance and glucosidase, xylosidase and aminopeptidase activities). 4. As predicted, the consumption of buried leaf litter by shredders was strongly influenced by the sediment structure. Effective porosity of 35% and 25% allowed the access to buried leaf litter for gammarids, whereas a lower porosity (12%) did not. As a consequence, leaf litter breakdown rates in columns with 35% and 25% effective porosity were twice as high as in the 12% condition. Microbial activity was poorly stimulated by gammarids, suggesting a low microbial contribution to leaf mass loss and a direct effect of gammarids through feeding activity. 5. Our results show that breakdown of POM in subsurface waters depends on the accessibility of food patches to shredders. [source]