Parsimoniously modelling perennial vegetation suitability and identifying priority areas to support China's re-vegetation program in the Loess Plateau: Matching model complexity to data availability     

Tim R. McVicar  Tom G. Van Niel  LingTao Li  ZhongMing Wen  QinKe Yang  Rui Li  Feng Jiao 《Forest Ecology and Management》2010,259(7):1277-1290

The Chinese Central government's policy to re-vegetate large areas of the Loess Plateau is currently being rapidly implemented at the provincial, prefecture, county, township, and village levels of government. Managers at these five levels of government need access to information to assist them to plan the land use change prior to performing on-ground activities. To this end, the suitability of 38 predominately native species in the 113,000 km² Coarse Sandy Hilly Catchments (CSHC) has been mapped at a 100 m resolution. In this data-sparse region, this was achieved by using a five-variable spatial overlay approach as we were able to readily access the required environmental variables and rule-set defining the species’ requirements (or tolerances). As the rules did not consider optimal growth they were possibly ‘too inclusive’, so the spatial extent of areas suggested for re-planting was refined by defining ‘target areas’ for trees, shrubs and grasses based on precipitation, aspect, landform, and slope. In the land-use planning criteria developed here we suggest that hill-slopes and gullies with slopes greater than or equal to 15° (defined from a 100 m resolution DEM) be left for natural succession. Due to lateral flow of water, sediment and nutrients from these steep slope and gullies, further prioritising re-vegetation target areas to the zone adjacent to and down slope from these steep portions of the landscape reduces sediment entering the river network with a minimal decrease of regional stream flow. These two functions (mapping species suitability and locating where priority and target re-vegetation activities should be undertaken) are available at a 100 m resolution for the entire CSHC by accessing a bilingual decision support tool called ReVegIH (Re-Vegetation Impacts on Hydrology). Finally, an ecohydrological model was used to simulate changes in average annual stream flow originating from the CSHC based on implementing the ‘target’ and ‘priority’ area re-vegetation activities within the constraints of two land limits.  相似文献   

Reactions on Nicotiana species to potato viruses A,X and Y and tobacco mosaic virus in relation to their taxonomy and geographical origin     

P. Van Dijk  C. Cuperus 《European journal of plant pathology / European Foundation for Plant Pathology》1989,95(6):343-356

When testing the response of species of the genusNicotiana to 14 isolates of potato viruses A (PVA), X (PVX) and Y (PVY) and tobacco mosaic virus (TMV), sections and section parts of the genus could be divided into five groups according to the overall reaction of their species. Species from arid regions of australia and belonging to the sectionSuaveolentes (subgenusPetunioides) were most sensitive and least resistant, whereas the sectionsPaniculatae (subgenusRustica),Tomentosae (Tabacum) andNoctiflorae (Petunioides) appeared least sensitive and most resistant. Sixty-one percent of the accessions of the latter sections proved resistant to at least two of the viruses. The most resistant species have their main geographical distribution in the central Andes (southern Peru, Bolivia and north-western Argentina), where the viruses may have originated. One other resistant species wasN. africana (Suaveolentes) indigenous to south-western Africa. The most sensitive American sections, viz.Genuinae (Tabacum) andTrigonophyllae, Alatae, Acuminatae andBigelovianae (Petunioides), were generally more sensitive than species of theSuaveolentes section from outside the arid regions of Australia. The remaining part of the genus, viz. the American sectionsThyrsiflorae andRusticae (Rustica) andUndulatae, Repandea andNudicaules (Petunioides) was intermediate between the latter group ofSuaveolentes species and the resistant group of sections with regard to sensitivity and resistance, but had a high rate of tolerance to PVA, PVX and PVY and of hypersensitivity-associated resistance to TMV. The results indicate that the viral respons in the genusNicotiana is mainly determined geographically and to a lesser extent taxonomically.Samenvatting Na inoculatie van een grote collectieNicotiana-soorten met 14 isolaten van de aardappelvirussen A (PVA), X (PVX) en Y (PVY) en tabaksmozaïekvirus (TMV), konden de secties of sectiedelen van het genus op basis van de gemiddelde reactie van hun soorten in vijf groepen worden verdeeld. Soorten uit Australische woestijngebieden en taxonomisch behorend tot de sectieSuaveolentes (subgenusPetunioides) bleken het meest gevoelig en het minst resistent, terwijl de sectiesPaniculatae (subgenusRustica),Tomentosae (Tabacum) enNoctiflorae (Petunioides) het minst gevoelig en het meest resistent waren. Van de collectienummers van de laatstgenoemde secties bleek 61% resistentie tegen minstens twee van de virussen te bezitten. De meest resistente soorten hebben hun verspreidingsgebied vooral in het centrale deel van het Andesgebergte (het zuidelijk deel van Peru, Bolivia en noord-westelijk Argentinië). Mogelijk is dit het ontstaansgebied van deze virussen. De einge andere resistente soort wasN. africana (Suaveolentes) uit zuid-westelijk Afrika. De meest gevoelige Amerikaanse secties, te wetenGenuinae (Tabacum) enTrigonophyllae, Alatae, Acuminatae enBigelovianae (Petunioides), waren gemiddeld gevoeliger danSuaveolentes-soorten die niet uit de Australische woestijnen afkomstig zijn. Het resterende deel van het genus, bestaande uit de Amerikaanse sectiesThyrsiflorae enRusticae (Rustica) enUndulatae, Repandae enNudicaules (Petunioides), stond met betrekking tot gevoeligheid en resistentie tussen laatstgenoemd deel van de sectieSuaveolentes en de groep resistente secties in, maar vertoonde in hoge mate tolerantie voor PVA, PVX en PVY en met overgevoeligheid samengaande resistentie voor TMV. Uit de resultaten blijkt dat de reacties van het genusNicotiana op virussen vooral geografisch bepaald zijn en in mindere mate taxonomisch.  相似文献   

The bionomics ofLiriomyza Trifolii on Gypsophila and Bean Leaves     

Jeanine H. W. M. Van Elferen  Shoshana Yathom 《Phytoparasitica》1989,17(4):241-250

A study was carried out to determine the distribution of feeding and oviposition punctures made byLiriomyza trifolii Burgess on gypsophila(Gypsophila paniculata ) and bean(Phaseolus vulgaris) leaves, and the development times of the immature stages on these plants. The absolute number of punctures per leaf area was much greater on bean leaves than on gypsophila leaves. The number of mines per leaf was also higher on beans than on gypsophila, but the ratio of mines/punctures was higher on gypsophila. Gypsophila leaves were punctured on both sides, but most of the punctures were on the distal third of the upper leaf side. On beans the punctures were dispersed uniformly on the upper side of the leaf. The larval period (±SE) at temperatures of 20, 25 and 30°C was 9.9±0.2, 4.4±0.1 and 3.7±0.1, and 5.5±O. l, 3.7±0.1 and 2.4±0.1 days, on gypsophila and bean, respectively. The pupal period at 17, 20, 25 and 30°C lasted 19.9±0.2, 14.7±0.1, 10.4±0.1 and 7.8±0.1 days, respectively.  相似文献   

Effect of the fungicide imazalil on hepatic microsomal cytochrome P-450 and cytochrome P-450 dependent activities in the Bobwhite quail (Colinus virginianus)     

Karel Lavrijsen  Jos Van Houdt  Dirk Van Dyck  Willem Meuldermans  Jos Heykants 《Pest management science》1990,29(1):47-56

Bobwhite quails were treated with imazalil for 8 weeks. The fungicide was given admixed in the food at 0, 100, 300, 500 and 1000 mg kg^?1. Even at the highest dose tested, imazalil did not affect the liver weight or the hepatic microsomal protein content. In treated quails, no significant induction of cytochrome P-450 or NADPH-cytochrome c-reductase activity was observed. Furthermore, imazalil did not induce or inhibit 7-ethoxyresorufin or 7-ethoxycoumarin O-deethylase in quail microsomes. Only a slight but significant increase by 35% and 49% in aniline hydroxylase activity was measured for the 500- and 1000-mg kg^?1 dose levels, respectively. After a drug-free period of one week, aniline hydroxylase activity returned to control values, indicating that the effect was fully reversible. It is concluded that imazalil does not induce or inhibit drug-metabolizing enzymes in the quail, even at doses which exceed by far the maximum levels currently used to dress seed under field conditions (100 mg kg^?1).  相似文献   

Population studies of the citrus psylla,trioza erytreae: factors influencing dispersal     

M. A. Van Den Berg  Susan H. Anderson  Valerie E. Deacon 《Phytoparasitica》1991,19(4):283-289

More adults of the citrus psylla,Trioza erytreae (Del Guercio) (Hemiptera: Triozidae), dispersed when the number of eggs, nymphs or adults on the citrus increased (positive correlations) and also when new leaves that were present decreased (negative correlation). More psylla were trapped close to high obstacles than in an open area, even though the obstacles were at a distance from the psylla-infested orchard.  相似文献   

Contaminant and formulation analysis of MSMA using high-pressure liquid chromatography — graphite furnace atomic absorption spectrophotometry     

Frans E. Pick  Pieter R. De Beer  Susan M. Prinsloo  Louis P. Van Dyk 《Pest management science》1987,21(1):45-49

High-pressure liquid chromatography with an ion-exchange column combined with graphite furnace atomic absorption spectrometry was used to analyse commercial formulations of sodium hydrogen methylarsonate (MSMA). No arsenite or arsenate salts or dimethylarsinic acid were detected as contaminants in the formulations, and the MSMA concentrations were found to be in accordance with the concentrations given on the containers.  相似文献   

Postponed germination of Puccinia recondita urediospores deposited on wheat seedlings. II. Infectivity of urediospores after postponed germination     

E. M. Van Hees-Boukema  J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1986,92(2):71-80

Urediospores ofPuccinia recondita f.sp.tritici were applied to wheat seedlings. Inoculated plants were placed in a growth chamber to expose the spores to dry periods from zero to nine days at near-optimal temperatures (ca 18 °C). The dry period was followed by a wet period varying from 2 to 24 hours for germination of spores and infection of plants. Infection results were subjected to analysis of variance. The main effects dry period, wet period, and temperature were highly significant. The dry period×wet period interaction was significant. The interaction implied that the effects of post-detachment, ripening of germinable spores appeared in their resulting infectivity. There were two forms of post-detachment ripening, a slow ripening during the dry period and a faster ripening during the wet period. The two forms of ripening showed a non-additive compensatory interaction. The effect of post-detachment ripening on infectivity of germinated spores was more pronounced at 15 than, at 18 or 20 °C; the effect was strongest during the first day of the dry period. At dry periods of over 6 days, infectivity of germinated spores decreased, especially at the higher temperatures. Prolonged exposure, of spores to a dry period apparently damages the spores even though they are still able to germinate.Samenvatting Uredosporen van de bruine roest van tarwe (Puccinia recondita f.sp.tritici) werden over het eerste blad van tarwekiemplanten verstoven. De aldus geïnoculeerde planten werden in een klimaatkamer geplaatst bij ca. 18 °C om de sporen bloot te stellen aan droge perioden van 0 tot 9 dagen. De droge perioden werden gevolgd door natte perioden van 2 tot 24 uur om de sporen te laten kiemen en de planten te infecteren. Na de natte periode werden de planten bij verschillende temperature geplaatst om de latente periode en de vorming van sporenhoopjes te bepalen. De hoofdeffecten op de vorming van sporenhoopjes waren zeer significant: duur van de droge periode, duur van de natte periode en temperatuur. Twee vormen van sporenrijping werden gevonden bij rijping vnn sporen, die los op het blad lagen (rijping, buiten de sporenhoopjes), een langzame rijping tijdens de droge periode en een snelle rijping tijdens de natte periode. Deze twee vormen van rijping vertoonden statistische interactie met enige wederzijdse compensatie. Het effect van deze sporenrijping (buiten de sporenhoopjes) op de infectiviteit van gekiemde sporen was bij 15 °C duidelijker dan bij 18 en 20 °C; het effect was het sterkst tijdens de eerste dag van de droge periode. Bij droge periodes langer dan 6 dagen daalde de infectiviteit, vooral bij de hogere temperaturen.  相似文献   

Identification of barley yellow mosaic virus by immuno-electron microscopy in barley but not in Polymyxa graminis or Lagena radicicola     

Willem G. Langenberg  Derk Van Der Wal 《European journal of plant pathology / European Foundation for Plant Pathology》1986,92(3):133-136

Samenvatting Gerstegeelmozaïekvirus (BaYMV) werd in een perceel wintergerst (cv. Igri) gevonden by Wittem in Limburg, Nederland. Het virus werd met immuno-elektronen-microscopie geïdentificeerd in bladweefsel als BaYMV. In de wortels van geïnfecteerde planten werden alle vormen die van de schimmel-vector (Polymyxa graminis Led.) bekend zijn aangetroffen nl. cystosori, plasmodia en zoosporangia. Inwendig kon geen BaYMV worden aangetoond of waargenomen inPolymyxa ofLagena spp.Cooperative investigation of the ARS, USDA, the Nebraska Agricultural Experiment Station, and the Plant Protection Service, Wageningen. Research conducted under Project 21-12. Published as Paper No. 7787, Journal Series, Nebraska Agricultural experiment Station. Mention of a trademark or proprietary product does not constitute a guarantee or warranty by the U.S. Department of Agriculture and does not imply its approval to the exclusion of other products that may also be suitable.  相似文献   

Molecular modifications of benzylphenol and benzyl-1,3-benzodioxole types of insect chemosterilants     

Gyrgy Matolcsy  Ren Feyereisen  Herman Van Mellaert  gnes Pl  Lszl Varjas  Ivn Blai  Pter Kulcsr 《Pest management science》1986,17(1):13-24

Rationally planned structural modifications were carried out on benzylphenols and benzyl-1,3-benzodioxoles described as fly chemosterilants and as anti-juvenile hormones. The introduction of a prop-2-ynyloxy group at various sites of the molecule resulted in compounds with a moderate inhibitory action on cytochrome P-450 mono-oxygenases, as measured by aldrin epoxidation. One compound, 5-(4-methoxybenzyl)-6-prop-2-ynyloxy-1,3-benzodioxole, revealed chemosterilant activity on Phormia regina, but its activity was less than that of the parent compounds. 2,4-Di-tert-butyl-6-[4-(3-methoxy-3-methylbutoxy)benzyl]phenol, which possessed a juvenoid structure, revealed no juvenile hormone (JH) activity but showed a high sterilant effect against Dysdercus cingulatus. In contrast to the parent substances, none of the tested compounds showed a detectable anti-JH effect in the Galleria assay. 8-Methoxy-2,3-methylenedioxydibenz[b,e]oxepine, a hitherto undescribed fused heterocyclic ring system, was devoid of activity, indicating the importance of free rotation and/or molecular flexibility. In spite of the moderate activities of these compounds, the manifold biological potential of the quinone-methide mechanism justifies further research on these lines.  相似文献   

Dispersal of Phytophthora nicotianae on tomatoes grown by nutrient film technique in a greenhouse     

G. Van Voorst  E. A. Van Os  J. C. Zadoks 《European journal of plant pathology / European Foundation for Plant Pathology》1987,93(4):195-199

Tomatoes were grown in a greenhouse by nutrient film technique (NFT). They were inoculated withPhytophthora nicotianae either by direct inoculation of roots or by adding fungal spores to a container with recirculating nutrient solution. In the first case, the resulting epidemic seemed to be polycyclic, in the second case monocyclic. In both cases, inoculum freely circulated through the NFT system and was present in the nutrient solutions for at least 6 days after inoculation.Samenvatting Kastomaten werden gekweekt met behulp van voedingsfilmtechniek. Zij werden geinoculeerd metPhytophthora nicotianae hetzij door directe besmetting van wortels, hetzij door een sporensuspensie toe te voegen aan het voorraadvat met voedingsoplossing. In het eerste geval leek een polycyclische epidemie te volgen. In het tweede geval ontstond een monomcyclische epidemie. In beide gevallen werd schimmelinoculum door het gehele gotensysteem rondgepompt. Inoculum bleef gedurende tenminste 6 dagen na inoculatie aantoonbaar in de voedingsoplossing.  相似文献