Interaction between water-soluble carbohydrate reserves and defoliation severity on the regrowth of perennial ryegrass (Lolium perenne L.)-dominant swards     

J. M. Lee  D. J. Donaghy†  P. Sathish‡  J. R. Roche 《Grass and Forage Science》2009,64(3):266-275

A field-study was undertaken in Hamilton, New Zealand to determine if there was an interaction between water-soluble carbohydrate (WSC) reserve content and defoliation severity on the regrowth of perennial ryegrass-dominant swards during winter. Perennial ryegrass plants with either low or high WSC content were obtained by varying the defoliation frequency. At the third defoliation at the one-leaf stage and at the first defoliation at the three-leaf stage (harvest H₁), swards were mown with a rotary lawnmower to residual stubble heights of 20, 40 or 60 mm. All swards were then allowed to regrow to the three-leaf stage before again defoliating to their treatment residual stubble heights (H₂). Frequently defoliated plants contained proportionately between 0·37 and 0·48 less WSC in the stubble after defoliation, depending on the severity of defoliation. There was no interaction between WSC content and defoliation severity for herbage regrowth between harvests H₁ and H₂. Herbage regrowth was lower from swards containing low WSC plants compared with high WSC plants (2279 vs. 2007 kg DM ha⁻¹). Furthermore, swards defoliated to 20 or 40 mm had greater herbage regrowth compared with those defoliated to 60 mm (2266, 2249 and 1914 kg DM ha⁻¹ for swards defoliated to residual stubble heights of 20, 40 and 60 mm, respectively). Regrowth of perennial ryegrass was positively correlated with post-defoliation stubble WSC content within defoliation severity treatment, implying that WSC contributed to the defoliation frequency-derived difference in herbage yield. However, the effect of defoliation severity on herbage regrowth was not associated with post-defoliation stubble WSC content.  相似文献   

Inhibitory Effect of N,N-Didesmethylgrossularine-1 on Inflammatory Cytokine Production in Lipopolysaccharide-Stimulated RAW 264.7 Cells     

Taiko Oda  Jong-Soo Lee  Yuta Sato  Yasuaki Kabe  Satoshi Sakamoto  Hiroshi Handa  Remy E. P. Mangindaan  Michio Namikoshi 《Marine drugs》2009,7(4):589-599

N,N-Didesmethylgrossularine-1 (DDMG-1), a compound with a rare α-carboline structure, was isolated from an Indonesian ascidian Polycarpa aurata as responsible for the observed inhibitory activity against TNF-α production in lipopolysaccharide-stimulated murine macrophage-like RAW264.7 cells. DDMG-1 inhibited the mRNA level of mTNF-α, IκB-α degradation, and binding of NF-κB to the target DNA site in LPS-stimulated RAW 264.7 cells. Moreover, DDMG-1 had an inhibitory effect on the production of IL-8, which is produced in CD14⁺-THP-1 cells stimulated by LPS. DDMG-1 is thus a promising drug candidate lead compound for the treatment of chronic inflammatory diseases, such as rheumatoid arthritis.  相似文献   

Preparation and acid dye adsorption behavior of polyurethane/chitosan composite foams     

Ho Cheon Lee  Young Gyu Jeong  Byung Gil Min  Won Seok Lyoo  Sang Cheol Lee 《Fibers and Polymers》2009,10(5):636-642

We prepared a series of polyurethane(PU)/chitosan composite foams with different chitosan content of 5∼20 wt% and investigated their adsorption performance of acid dye (Acid Violet 48) in aqueous solutions with various dye concentrations and pH values. It was observed that PU/chitosan composite foams exhibited well-developed open cell structures. Dye adsorption capacities of the composite foams increased with the increment of chitosan content in composite foams, because amine groups of chitosan serve as the binding sites for sulfonic ions of acid dyes in aqueous solutions. In addition, dye adsorption capacities of composite foams were found to increase with decreasing the pH value, which stems from the fact that the enhanced chemisorption between protonated amine groups of chitosan and sulfonic ions of acid dye is available in acidic solutions. The dye adsoption kinetics and equilibrium isotherm of the composite foams were well described with the pseudo-second order kinetic model and Langmuir isotherm model, respectively. The maximum adsorption capacity (q _max) for the PU/chitosan composite foams with 20 wt% chitosan content is evaluated to be ca. 30 mg/g.  相似文献   

Endosperm-Specific Expression of Serotonin <Emphasis Type="Italic">N</Emphasis>-Hydroxycinnamoyltransferase in Rice   总被引：1，自引：0，他引：1  

Lee K  Kang K  Park M  Woo YM  Back K 《Plant foods for human nutrition (Dordrecht, Netherlands)》2008,63(2):53-57

Serotonin N-hydroxycinnamoyltransferase (SHT) is a key enzyme in the synthesis of feruloylserotonin (FS) and 4-coumaroylserotonin (CS). These serotonin derivatives show strong antioxidant activity, making them valuable for both nutritional and pharmacological use in humans. Ectopic expression of SHT under the control of the endosperm specific-glutelin and prolamin promoters from rice was produced via Agrobacterium-mediated transformation. SHT expression was confirmed by Southern blot analysis, followed by Northern blotting and SHT enzyme activity analyses using total RNA and protein, respectively, extracted from transgenic seeds. The glutelin A3 (GluA3) promoter produced low SHT mRNA expression in rice seeds, whereas the prolamin promoter expressed high levels of SHT mRNA. In spite of the ectopic expression of SHT in rice seeds, both transgenic genotypes accumulated levels of serotonin derivatives similar to those found in wild-type rice. Furthermore, our data suggest that serotonin, rather than phenylpropanid-CoAs, is the rate-limiting substrate in the biosynthesis of serotonin derivatives in SHT-overexpressing transgenic rice seeds.  相似文献   

Modeling mid-rotation fertilizer responses using the age-shift approach     

Colleen A. Carlson  Thomas R. Fox  H. Lee Allen  Timothy J. Albaugh  Forest Nutrition Cooperative 《Forest Ecology and Management》2008,256(3):256

Growth and yield modelers have incorporated mid-rotation fertilizer responses by: modifying site index; developing new models to include fertilizer responses directly; using multipliers or additional terms to scale existing models. We investigated the use of age-shifts to model mid-rotation fertilizer responses. Age-shift prediction models were constructed from 43 installations of a nitrogen (0, 112, 224 and 336 kg ha⁻¹ elemental) by phosphorus (0, 28 and 56 kg ha⁻¹ elemental) factorial experiment established in mid-rotation loblolly (Pinus taeda L.) pine stands in the southeastern US. Age-shifts for dominant height and basal area increased with time after fertilization, to a maximum and then either remained fairly constant, or declined. The initial rate of increase, maximum age-shift and decline were functions of the rate and combinations of fertilizers applied, as well as stand density and age at fertilization. Volume age-shifts increased linearly throughout the 10-year measurement period for most treatments with the rate of increase being a function of the elements applied, stocking, site index and age at fertilization. A mid-rotation fertilizer application of 224 and 28 kg ha⁻¹ elemental N and P, respectively, resulted in age-shifts of 1.1, 1.9 and 2.4 years for dominant height, basal area and volume, respectively, 10 years after fertilization. The age-shifts were incorporated into growth and yield models.  相似文献   

Estimation of fire severity by use of Landsat TM images and its relevance to vegetation and topography in the 2000 Samcheok forest fire   总被引：1，自引：0，他引：1  

Byungdoo Lee  Seon Young Kim  Joosang Chung  Pil Sun Park 《Journal of Forest Research》2008,13(4):197-204

The severity of the 2000 Samcheok forest fire was classified by using Landsat TM images, and the effects of vegetation structures and topographic conditions on fire severity were analyzed. The estimated normalized difference vegetation index differences between the pre and post-fire Landsat TM images were used as the criteria in determining the levels of fire severity–low, moderate, and extreme. According to the results from fire severity estimation, of the 10,600 ha forest stands, 28% was severely damaged by crown fires, 38% was moderately damaged, and the remaining 34% was damaged slightly by surface fires. The overall accuracy of the fire severity classification was 83% (Kappa coefficient = 0.76). The results of χ ²-tests showed that fire severity differed significantly with the vegetation and topographic conditions as follows. The coniferous stands, compared with the mixed and broad-leaved, were more vulnerable to fire damage; the higher the slope of fire sites, the greater the fire damage; the south was the most vulnerable aspect; fire severity of coniferous forest stands increased with increasing elevation. However, in the study area it was found that fire severity of broad-leaved forest stands were negatively related to the elevation of the corresponding fire sites and affected more by vegetation conditions rather than by topographic conditions.  相似文献   

创造性地铺装——转变传统观念，在您的庭院铺装中注入设计元素     

张劲农  李·安妮·怀特 《广东园林》2008,30(1):67-68

铺装是庭院里最实用的元素之一,若是能在铺装中注入设计元素,您的庭院将会别具一格。  相似文献   

Attraction and antennal response of the common wasp,Vespula vulgaris (L.), to selected synthetic chemicals in New Zealand beech forests     

Ashraf M El‐Sayed  Lee‐Anne Manning  C Rikard Unelius  Kye Chung Park  Lloyd D Stringer  Nicola White  Barry Bunn  Andrew Twidle  David M Suckling 《Pest management science》2009,65(9):975-981

BACKGROUND: The common wasp, Vespula vulgaris (L.), and the German wasp, Vespula germanica (F.), are significant problems in New Zealand beech forests (Nothofagus spp.), adversely affecting native birds and invertebrate biodiversity. This work was undertaken to develop synthetic attractants for these species to enable more efficient monitoring and management. RESULTS: Seven known wasp attractants (acetic acid, butyl butyrate, isobutanol, heptyl butyrate, octyl butyrate and 2,4‐hexadienyl butyrate) were field tested, and only heptyl butyrate and octyl butyrate attracted significantly higher numbers of wasps than a non‐baited trap. Accordingly, a series of straight‐chain esters from methyl to decyl butyrate were prepared and field tested for attraction of social wasps. Peak biological activity occurred with hexyl butyrate, heptyl butyrate, octyl butyrate and nonyl butyrate. Polyethylene bags emitting approximately 18.4–22.6 mg day^?1 of heptyl butyrate were more attractive than polyethylene bags emitting approximately 14.7–16.8 mg day^?1 of heptyl butyrate in the field. Electroantennogram (EAG) studies indicated that queens and workers of V. vulgaris had olfactory receptor neurons responding to various aliphatic butyrates. CONCLUSION: These results are the first to be reported on the EAG response and the attraction of social wasps to synthetic chemicals in New Zealand beech forests and will enable monitoring of social wasp activity in beech forests. Copyright © 2009 Society of Chemical Industry  相似文献   

Classification of Dry-Milled Maize Grit Yield Groups Using Quadratic Discriminant Analysis and Decision Tree Algorithm     

Kyung-Min Lee  Timothy J. Herrman  Scott R. Bean  David S. Jackson  Jane Lingenfelser 《Cereal Chemistry》2007,84(2):152-161

A genetically and environmentally diverse collection of maize (Zea maize L.) samples was evaluated for physical properties and grit yield to help develop a standard set of criteria to identify grain best suited for dry-milling. Application of principal component analysis (PCA) reduced a set of approximately 500 samples collected from six states to 154 maize hybrids. Selected maize hybrids were placed into seven groups according to their dry-milled grit yields. Regression analysis explained only 50% of the variability in dry-milling grit yield. Patterns of differences in the physical properties for the seven grit yield groups implied that the seven yield groups could be placed into two or three groups. Using two pattern recognition techniques for improving classification accuracy, quadratic discriminant analysis and the classification and regression tree (CART) model, dry-milled grit yield groups were predicted. The estimated correct classification rates were 69–80% when the samples were divided into three yield groups and 81–90% when samples were divided into two yield groups. The results indicated the comparable success of both techniques and the superiority of the decision tree algorithm to quadratic discriminant analysis by offering higher accuracy and clearer classification rules in differentiating among dry-milled grit yield groups.  相似文献   

Induction, Regulation, and Role in Pathogenesis of Appressoria in Monilinia fructicola     

Lee MH  Bostock RM 《Phytopathology》2006,96(10):1072-1080

ABSTRACT Monilinia fructicola, which causes brown rot in stone fruit, forms appressoria on plant and artificial surfaces. On nectarine, the frequency of appressoria produced by conidial germlings depends to a large degree on the stage of fruit development, with numerous appressoria formed on immature (stage II) nectarine fruit, and no appressoria observed on fully mature fruit (late stage III). On polystyrene surfaces, appressorium formation was increased from <10% of germinated conidia to >95% of germinated conidia when the conidia were washed to remove residual nutrients and self-inhibitors. M. fructicola appressorium formation also appears to be regulated by the topography of the plant surface. On fruit, appressoria formed on stomatal guard cell lips, on the grooves of lateral cells adjacent to stomata or between two epidermal cells, and on the convex surfaces of epidermal cells. Pharmacological effectors indicate that cyclic AMP-, MAP kinase-, and calcium/calmodulin-dependent signaling pathways are involved in the induction and development of appressoria. KN-93, an inhibitor of calmodulin-dependent protein kinase II, did not inhibit conidial germination but did inhibit appressorium formation and brown rot development on flower petals, suggesting that appressoria are required for full symptom development on Prunus spp. petals.  相似文献