Empirical relationships between land use/cover and estuarine condition in the Northeastern United States   总被引：1，自引：0，他引：1  

Wilfrid Rodriguez  Peter V. August  Yeqiao Wang  John F. Paul  Arthur Gold  Norman Rubinstein 《Landscape Ecology》2007,22(3):403-417

Land–water interactions were examined in three regions in the Virginian Biogeographic Province; the southern shore of Cape Cod, Massachusetts; the Hudson/Raritan region of New York; and the eastern shore of the Delmarva (Delaware/Maryland/Virginia) Peninsula. Cumulative distribution functions were used to evaluate similarity in environmental condition among estuaries. Spatial-setting variables (location in a river, coastal lagoon, or in open waters) were associated with variation for some measures of estuarine condition. Patterns of coastal urban and agriculture gradients were measured and their relationship with indicators of estuarine condition was modeled statistically. When estuaries were pooled, the highest variation explained by spatial-setting variables was found for dissolved oxygen (DO, R ² = 0.44) and salinity (R ² = 0.58), with DO decreasing in river locations and salinity decreasing with rainfall and sampling locations near rivers. The explanatory power for the other indicator variables was low and varied from 6% to 27%. Rainfall explained some of the variation (R ² = 0.23) in total suspended solids. Moderate (0.4 < | r | < 0.7) to strong (| r | ≥ 0.7) linear associations were found between total urban area and measures of estuarine condition. Within regions, total urban area was positively associated with Silver (r = 0.59), Cadmium (r = 0.65), and Mercury (r = 0.47) in Cape Cod, and inversely related to DO (r = −0.65) in the Hudson/Raritan region. No associations were found in the Delmarva Peninsula study area. Total area of agriculture showed a moderate association with Arsenic in Cape Cod, but no other associations were found in the other two regions. Our analyses show a measurable impact of urban land use on coastal ecosystem condition over large areas of the northeastern United States. This pattern was most evident when many different landscapes were considered simultaneously. The relationship between urban development and estuarine condition were weaker within the individual regions studied. The use of land use/cover models for predicting estuarine condition is a challenging task that warrants enhancements in the type, quantity, and quality of data to improve our ability to discern relationships between anthropogenic activities on land and the condition of coastal environments.  相似文献   

Habitat selection and breeding success in a forest-nesting Alcid,the marbled murrelet,in two landscapes with different degrees of forest fragmentation     

Yuri Zharikov  David B. Lank  Falk Huettmann  Russell W. Bradley  Nadine Parker  Peggy P.-W. Yen  Laura A. Mcfarlane-Tranquilla  Fred Cooke 《Landscape Ecology》2007,22(5):791-791

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A theory greyer than grey     

Mohan K. Wali 《Landscape Ecology》2007,22(2):319-322

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Parasitism of <Emphasis Type="Italic">Trichoderma</Emphasis> on <Emphasis Type="Italic">Meloidogyne javanica</Emphasis> and role of the gelatinous matrix     

Edna Sharon  Ilan Chet  Ada Viterbo  Meira Bar-Eyal  Harel Nagan  Gary J. Samuels  Yitzhak Spiegel 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(3):247-258

Trichoderma (T. asperellum-203, 44 and GH11; T. atroviride-IMI 206040 and T. harzianum-248) parasitism on Meloidogyne javanica life stages was examined in vitro. Conidium attachment and parasitism differed beween the fungi. Egg masses, their derived eggs and second-stage juveniles (J2) were parasitized by Trichoderma asperellum-203, 44, and T. atroviride following conidium attachment. Trichoderma asperellum-GH11 attached to the nematodes but exhibited reduced penetration, whereas growth of T. harzianum-248 attached to egg masses was inhibited. Only a few conidia of the different fungi were attached to eggs and J2s without gelatinous matrix; the eggs were penetrated and parasitized by few hyphae, while J2s were rarely parasitized by the fungi. The gelatinous matrix specifically induced J2 immobilization by T. asperellum-203, 44 and T. atroviride metabolites that immobilized the J2s. A constitutive-GFP-expressing T. asperellum-203 construct was used to visualize fungal penetration of the nematodes. Scanning electron microscopy revealed the formation of coiling and appressorium-like structures upon attachment and parasitism by T. asperellum-203 and T. atroviride. Gelatinous matrix agglutinated T. asperellum-203 and T. atroviride conidia, a process that was Ca²⁺-dependent. Conidium agglutination was inhibited by carbohydrates, including fucose, as was conidium attachment to the nematodes. All but T. harzianum could grow on the gelatinous matrix, which enhanced conidium germination. A biomimetic system based on gelatinous-matrix-coated nylon fibers demonstrated the role of the matrix in parasitism: T. asperellum-203 and T. atroviride conidia attached specifically to the gelatinous-matrix-coated fibers and parasitic growth patterns, such as coiling, branching and appressoria-like structures, were induced in both fungi, similarly to those observed during nematode parasitism. All Trichoderma isolates exhibited nematode biocontrol activity in pot experiments with tomato plants. Parasitic interactions were demonstrated in planta: females and egg masses dissected from tomato roots grown in T. asperellum-203-treated soil were examined and found to be parasitized by the fungus. This study demonstrates biocontrol activities of Trichoderma isolates and their parasitic capabilities on M. javanica, elucidating the importance of the gelatinous matrix in the fungal parasitism.  相似文献   

Aloe ring spot,a new disease of aloe caused by <Emphasis Type="Italic">Haematonectria haematococca</Emphasis> (Berk. &; Broome) Samuels &; Nirenberg (anamorph: <Emphasis Type="Italic">Fusarium</Emphasis> sp.)     

Yuuri Hirooka  Takao Kobayashi  Jun Takeuchi  Tsuyoshi Ono  Yasunori Ono  Keiko T. Natsuaki 《Journal of General Plant Pathology》2007,73(5):330-335

A ring spot disease of Aloe vera was found on leaves of potted seedlings of Aloe vera in Hachijojima and Chichijima Islands, Tokyo. From tissue of ring spot lesions, a fungus producing Fusarium-type conidia was consistently isolated. After 1 month, reddish perithecia of nectriaceous fungus had formed on the colonies of this isolate on PDA. These nectriaceous and Fusarium fungi were identified as Haematonectria haematococca and Fusarium sp., respectively. From a single ascospore isolation, the former was confirmed to be the teleomorph of the Fusarium sp. Typical ring spot lesions were reproduced by artificial inoculations using single ascospore and single conidium isolates. Inoculations of five species of genus Aloe revealed that they were highly susceptible except for A. arborescens. This is the first report of a disease on Aloe caused by H. haematococca (anamorph: Fusarium sp.) in Japan, and it was named aloe ring spot.  相似文献   

Relating plant and pathogen development to optimise fungicide control of phoma stem canker (<Emphasis Type="Italic">Leptosphaeria maculans</Emphasis>) on winter oilseed rape (<Emphasis Type="Italic">Brassica</Emphasis><Emphasis Type="Italic">napus</Emphasis>)     

Julie M. Steed  Andreas Baierl  Bruce D. L. Fitt 《European journal of plant pathology / European Foundation for Plant Pathology》2007,118(4):359-373

In winter oilseed rape experiments at Rothamsted in 2000/01 to 2002/03 growing seasons, the severity of phoma stem canker epidemics in summer depended on the timing of phoma leaf spot epidemics in the previous autumn, and hence on the timing of Leptosphaeria maculans ascospore release. The first major release of L. maculans ascospores was earlier in 2000 (26 September) and 2001 (18 September) than in 2002 (21 October). Consequently, the autumn phoma leaf spot epidemic was also earlier in 2000 and 2001 than in 2002. The resulting stem canker epidemics were severe by harvest (July) in 2001 and 2002 but not in 2003. No correlation was found between the severity or duration of phoma leaf spotting (lesion days or lesion °C-days) and the subsequent severity of phoma stem canker epidemics. Rates of leaf production and loss were similar in the three growing seasons. Out of ca. 25 leaves produced on plants during each season, leaf numbers 10–14 generally remained on plants for the longest. Treatment with flusilazole + carbendazim in autumn decreased the severity of phoma leaf spotting for several weeks after treatment, decreased the severity of stem canker the following summer and increased yield significantly in 2001 and 2002 but not in 2003. The most effective timings for flusilazole + carbendazim application were when leaves 7–11 were present on most plants and at least 10% of plants were affected by phoma leaf spot. Two half-dose applications of fungicide reduced phoma stem canker and increased yield more than a single full dose application when phoma leaf spot epidemics were early (<800 °C-days after sowing).  相似文献   

Genomic analysis of antifungal metabolite production by <Emphasis Type="Italic">Pseudomonas fluorescens</Emphasis> Pf-5     

Joyce E. Loper  Harald Gross 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(3):265-278

The complete genomic sequences of several Pseudomonas spp. that inhabit the rhizosphere are now available, providing a new opportunity to advance knowledge of plant growth-promoting rhizobacteria (PGPR) through genomics. Among these is the biological control bacterium Pseudomonas fluorescens Pf-5. Nearly 6% of the 7.07 Mb genome of Pf-5 is devoted to the biosynthesis of secondary metabolites, including antibiotics toxic to soilborne fungi and Oomycetes that infect plant roots, and two siderophores involved in iron acquisition. Three orphan gene clusters, for which the encoded natural product was unknown, also were identified in the genome of Pf-5. The product synthesized from one of the orphan gene clusters was identified recently using a new ‘genomisotopic approach’, which employs a combination of genomic sequence analysis and isotope guided fractionation. Application of the genomisotopic approach to one orphan gene cluster in Pf-5 resulted in the discovery of orfamide A, founder of a new group of bioactive cyclic lipopeptides with a putative role in biological control of plant disease.  相似文献   

<Emphasis Type="Italic">Amaranthus leaf mottle virus</Emphasis>: 3′-end RNA sequence proves classification as distinct virus and reveals affinities within the genus <Emphasis Type="Italic">Potyvirus</Emphasis>     

Eduardo Segundo  Dietrich E. Lesemann  Germán Martín  María P. Carmona  Leticia Ruiz  Isabel M. Cuadrado  Leonardo Velasco  Dirk Janssen 《European journal of plant pathology / European Foundation for Plant Pathology》2007,117(1):81-87

Amaranthus leaf mottle virus (AmLMV) was classified as a member of the genus Potyvirus on the basis of its particle morphology, serology, and biological properties (Casetta et al., 1986). Based on these properties, an Amaranthus viridis-infecting virus isolated in Spain, causing mottle and leaf blistering as well as reduced growth has been identified as AmLMV. The 3′ terminal genomic region of this and a reference isolate from Italy has been sequenced and reveals a 95% nucleotide identity between the two isolates. The sequenced part comprises the coat protein with 281 amino acids and 315 nucleotides of the 3′ untranslated region (UTR) preceding a polyadenylated tail. Pairwise comparisons and phylogenetic analysis of the nucleotide and deduced amino acid sequences of the CP and 3′ UTR of the cloned cDNAs with those of other potyviruses shows that AmLMV is a distinct potyvirus closely related to Potato virus Y.  相似文献   

Variability in response to toosendanin in a laboratory colony of<Emphasis Type="Italic">Trichoplusia ni</Emphasis>     

Jennifer H. Cameron  Murray B. Isman  Mahesh K. Upadhyaya 《Phytoparasitica》2007,35(2):119-122

Laboratory rearing of insects for scientific research ensures a constant supply of insects. However, laboratory colonies may diverge genetically and/or phenotypically from wild populations due to selection pressures in their artificial environment. This study examined how variation in a colony ofTrichoplusia ni influenced reproducibility over time of bioassays of toosendanin (a limonoid extracted from the bark ofMelia azedarach). In four of five experiments insect growth was reduced significantly (P=0.05) by the presence of toosendanin in the diet. The fifth experiment showed the same trend, but the effect was not significant. Mean larval mass of both control and treated insects also varied greatly among experiments. The considerable variability observed in this population highlights the importance of replicating experiments in time, and not just space, to confirm reproducibility of treatment effects. http://www.phytoparasitica.org posting Jan. 23, 2007.  相似文献   

Detecting<Emphasis Type="Italic">Orobanche</Emphasis> species by using cpDNA diagnostic markers     

B. Román  C. I. González Verdejo  Z. Satovic  M. D. Madrid  J. I. Cubero  S. Nadal 《Phytoparasitica》2007,35(2):129-135

Some species of the genusOrobanche are among the most devastating parasitic weeds, causing extensive damage in agricultural fields. Considering the difficult control due to seed longevity in the soil, small seed size, high fecundity and a subterranean phase that allows them to parasitize the host before they emerge and become evident, the development of diagnostic markers is highly recommended. In our study we identified potential molecular diagnostic markers from the plastid genome in order to distinguish among the most importantOrobanche species attacking crops in Andalusia, the southern region of the Iberian Peninsula. The study has consideredO. crenata, O ramosa andO. cumana causing serious losses in legumes, solanaceous crops and sunflower fields, respectively, andO. minor that, although abundant in Andalusia, has to our knowledge not yet been found parasitizing agricultural hosts. We amplified a non-coding region from the plastid genome, studied sequence differences among the amplified fragments and digested those of the same length with selected restriction enzymes. Here, we propose a molecular protocol to distinguish the main parasitic plants in crop fields of southern Spain. Different applications such as identification ofOrobanche seeds in soil or crop seed lots are discussed in order to offer right crop recommendations or to prevent new infestation of parasite-free fields. Recommendations for further development of these diagnostic markers are also considered. http://www.phytoparasitica.org posting Jan. 15, 2007.  相似文献