Selenium hyperaccumulation offers protection from cell disruptor herbivores     

Colin F Quinn  John L Freeman  Ray JB Reynolds  Jennifer J Cappa  Sirine C Fakra  Matthew A Marcus  Stormy D Lindblom  Erin K Quinn  Lindsay E Bennett  Elizabeth AH Pilon-Smits 《BMC ecology》2010,10(1):19

Background  

Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores and pathogens. Previous research has shown that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium hyperaccumulating plants sequester Se in discrete locations in the leaf periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus against two cell disrupting herbivores, the western flower thrips (Frankliniella occidentalis) and the two-spotted spider mite (Tetranychus urticae).  相似文献   

Folate Polyglutamylation is Required for Rice Seed Development   总被引：1，自引：0，他引：1  

Nampeung Anukul  Riza Abilgos Ramos  Payam Mehrshahi  Anahi Santoyo Castelazo  Helen Parker  Anne Diévart  Nadège Lanau  Delphine Mieulet  Gregory Tucker  Emmanuel Guiderdoni  David A. Barrett  Malcolm J. Bennett 《Rice》2010,3(2-3):181-193

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Distinguishing Cyperus rotundus from Some Related Species     

C. Parker 《国际虫害防治杂志》2013,59(4):477-482

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The Effect of Numerous Herbicides on the Germination of Orobanche aegyptiaca and Striga hermontheca     

L. Kasasian  C. Parker 《国际虫害防治杂志》2013,59(4):471-481

Abstract

Two hundred and thirty seven chemicals were tested to determine their effect on the germination of Orobanche aegyptiaca and Striga hermontheca. From their activity in these tests and a knowledge of their general properties the following are regarded as being the most promising for the pre-em. control of (1) Orobanche — oryzalin, dichlobenil, chlorthiamid, nitralin and chloramben. (2) Striga — 2, 4-D, MCPA and a range of other phenoxy compounds, chlorfenac, with MON 097, prynachlor, PH 40–21, PRB-8, RU 12068 and U 27658 showing the most interesting activity among the newer compounds.  相似文献   

The Experimental Application of Insecticides from a Helicopter for the Control of Riverine Populations of Glossina tachinoides in West Africa. II. Calibration of Equipment and Insecticide Dispersal     

C. W. Lee  J. D. Parker  D. A. T. Baldry  D. H. Molyneux 《国际虫害防治杂志》2013,59(4):404-422

Abstract

Trials were carried out in Upper Volta to assess equipment for the application of insecticides as aerosol from helicopters for the control of riverine tsetse flies (G. tachinoides). Flying techniques were developed to direct aerosols in the downwash of the helicopter to tsetse breeding sites close to the water's edge. Good penetration of droplets below the riverine canopy was achieved during the late afternoon and early morning when weather conditions were very stable.  相似文献   

Plant Disease Control     

C. W. Lee  J. D. Parker  B. Philippon  D. A. T. Baldry 《国际虫害防治杂志》2013,59(1):92-94

Abstract

Experiments have been carried out in the Ivory Coast to assess the performance of a prototype rapid release system to apply larvicides for the control of S. damnosum, the vector of onchocerciasis. The equipment was fitted to a Pilatus Porter aircraft and was used to apply Abate larvicide to a large river during conditions of low water level. It was shown that the equipment could accurately deliver volumes of larvicide between one and 50 l and that these quantities could be placed exactly along chosen points in the river, provided the aircraft was flown along the direction of the watercourse. Satisfactory control of S. damnosum larvae was achieved at three sites using a dosage rate of 0.05 ppm/10 min of waterflow. However, it was recommended that a dosage of 0.1 ppm/10 min be adopted in future work because some of the more extensive sites treated were underdosed. It was not possible to assess the biological effectiveness of the equipment for treating small rivers, but physical tests were carried out which suggest that the system should be suitable for applying larvicide to rivers as narrow as five metres width. Recommendations were made to improve the reliability of the equipment for use in an operational onchocerciasis programme.  相似文献   

Grassland community composition drives small-scale spatial patterns in soil properties and processes     

Sophie S. Parker  Eric W. Seabloom  Joshua P. Schimel 《Geoderma》2012

The presence and activity of individual plants can affect soil resource availability and microbial processes, and can influence the spatial scale over which soil properties vary. While soils have been found to differ under plants of differing growth form (i.e. grasses vs. trees), few studies have focused on small-scale soil differences under comparably-sized species. Here we investigate how two types of C-3 grasses influence patterns in soil properties and processes at scales of less than one meter in a California grassland. To understand how native perennial grasses differ from invasive annual grasses in their effects on soils, we used cross-semivariogram analysis to quantify the degree and scale of spatial heterogeneity in soil properties and processes in experimentally-seeded grasslands. We then used mapping techniques to correlate spatial patterns of soil properties and processes with the cover of annual and perennial grasses aboveground. We found that many soil properties and processes belowground were spatially-correlated with the aboveground presence of annuals or perennials. Soil moisture became more heterogeneous with increasing amounts of perennial cover, suggesting that perennial bunchgrass individuals take up more water and produce zones of resource depletion in comparison with soils directly under annual grasses. The association of belowground resources and activity with the two types of grass suggests that the historical shift from perennial to annual dominance in California grasslands led to changes in the small-scale spatial structure of soil properties and processes in these systems. These changes may alter ecosystem function and could potentially perpetuate invasive annual grass dominance.  相似文献   

Helpful hints in the cutting and planting of seed potatoes     

Albert G. Fradkin  George F. Dow  M. W. Parker 《American Journal of Potato Research》1963,40(3):103-107

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Effect of the Medium Replacement Interval on the Viability,Growth and In Vitro Maturation of Isolated Caprine and Ovine Pre‐Antral Follicles     

DM Magalhães  DD Fernandes  MBS Mororó  CMG Silva  GQ Rodrigues  JB Bruno  MHT Matos  CC Campello  JR Figueiredo 《Reproduction in domestic animals》2011,46(1):134-140

The aim of the present study was to evaluate the effects of different medium replacement intervals on the viability, antral cavity formation, growth and in vitro maturation (IVM) of oocytes from caprine and ovine pre‐antral follicles. Pre‐antral ovarian follicles (≥150 μm) were isolated from the ovarian cortex of goats and sheep and were individually cultured for 24 days using two different medium replacement intervals [2 days (T₁) or 6 days (T₂)]. Follicle development was evaluated on the basis of antral cavity formation, increases in follicular diameter and the presence of healthy cumulus oocyte complexes and fully grown oocytes. For caprine species, results showed a higher percentage (p < 0.05) of viable follicles in T₁ than T₂ from day 6 until the end of the culture. In addition, when comparing both treatments after the same culture duration, the rate of antrum formation was significantly higher in T₁ than in T₂ from day 12 onwards. Yet, in ovines, when both treatments were compared on day 24 of the culture, there were more viable follicles in T₂ than in T₁ (p < 0.05). In the caprine species, percentages of fully grown oocytes (≥110 μm) acceptable for IVM after 24 days of culture were significantly higher in normal follicles cultured in T₁ (30.0%) than in T₂ (6.7%; p < 0.05). On the other hand, in ovines, at the end of the culture, the percentage of oocytes destined for IVM was higher in T₂ than in T₁ (23.5% vs 2.9%; p < 0.05). In conclusion, under the same conditions, the frequency of medium replacement significantly affected the in vitro development of caprine and ovine pre‐antral follicles. To improve the efficiency of the culture system, the medium must be replaced every 2 and 6 days for goat and sheep pre‐antral follicles, respectively.  相似文献   

Pathology in practice. Histomoniasis     

Brinson DL  Williams SM  Parker WA  Armour NK  Collett SR 《Journal of the American Veterinary Medical Association》2011,238(8):987-989

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