4 research outputs found

    USING SUNFLOWER WILD SPECIES TO IMPROVE RESISTANCE OF CULTIVATED SPECIE TO THE PARASITE BROOMRAPE (OROBANCHE CUMANA WALLR.)

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    The parasitic plant Orobanche cumana (broomrape) is the most important biotic constraint to the production of sunflower, in all countries around the word. The aim of our study was evaluation of populations of some wild Helianthus species to broomrape populations that are highly virulent in Romania. All resistant interspecific population derived from crosses with annual specie Helianthus debilis and perennial specie Helianthus maximiliani. Testing of this interspecific populations indicate the possibility to obtain sources of resistance to broomrape populations present in Romania, but also in countries situated around Black Sea region

    Forested riparian buffers change the taxonomic and functional composition of stream invertebrate communities in agricultural catchments

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    Riparian zones form the interface between stream and terrestrial ecosystems and play a key role through their vegetation structure in determining stream biodiversity, ecosystem functioning and regulating human impacts, such as warming, nutrient enrichment and sedimentation. We assessed how differing riparian vegetation types influence the structural and functional composition (based on species traits) of stream invertebrate communities in agricultural catchments. We characterized riparian and stream habitat conditions and sampled stream invertebrate communities in 10 independent site pairs, each comprising one “unbuffered” reach lacking woody riparian vegetation and a second downstream reach with a woody riparian buffer. Forested riparian buffers were associated with greater shading, increased gravel content in stream substrates and faster flow velocities. We detected changes in invertebrate taxonomic composition in response to buffer presence, with an increase in sensitive Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa and increases in key invertebrate species traits, including species with preference for gravel substrates and aerial active dispersal as adults. Riparian vegetation independently explained most variation in taxa composition, whereas riparian and instream habitat together explained most variation in functional composition. Our results highlight how changes in stream invertebrate trait distributions may indirectly reflect differences in riparian habitat, with implications for stream health and cross-ecosystem connectivity

    Genetic Variation of Juniperus squamata var. morrisonicola Based on ISSR Markers

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    玉山圓柏(Juniperus squamata var. morrisonicola)生長在海拔3,000公尺以上高山,是台灣針葉樹種分布最高者,群落的形態有極大差異,生長型的變異範圍由匍伏灌木至直立喬木。以13個ISSR引子研究玉山圓柏10個族群160個個體,共得到173個條帶,其中83為多型性條帶(48.98%)。AMOVA分析顯示,地理區域間變方成分佔3.85%(P=0.0933),地區內族群間佔9.06%(P < 0.001),族群內個體間變方成分佔87.09%(P <0.001)。POPGENE的分析結果顯示,各族群內之基因歧異度值由0.294- 0.372,總的Nei’s基因歧異度(Ht)為0.384,遺傳分化係數(Gst)為0.117,基因流(Nm)為3.765。由這些結果看來,玉山圓柏族群基因流暢通,族群間分化程度與一般針葉樹相近。比較關山族群喬木與灌木兩種不同生長型個體,發現兩種生長型間無顯著遺傳差異。南湖大山地區的南湖池直立喬木族群與南湖大山北峰匍伏灌木族群間,有顯著的遺傳分化。Juniperus squamata var. morrisonicola is distributed in mountains above 3,000m in altitude and is the conifer species with highest altitudinal distribution in Taiwan. The species is highly variable in growth forms, ranging from low procumbent to tall tree. One hundred and sixty individuals from ten populations were studied for ISSR variation. One hundred and seventy-three bands were observed using 13 primers. Eighty-three (48.98%) were polymorphic bands. AMOVA analysis revealed that the percentages of variance components attributable to variation among regions, among populations within regions, and among individuals within populations were 3.85% (p=0.0933), 9.06% (p<0.001), and 87.09% (p<0.001), respectively. The result indicated that there was a slight but signification differentiation among populations. However, the major variation existed among individuals within populations. POPGENE analysis revealed that the total gene diversity (Ht) of the species was 0.384 and the gene diversities of populations ranged from 0.294 to 0.372. The population genetic diversity index (Gst) was 0.117 while the gene flow index (Nm) was 3.765. The result indicated that the gene flow among populations was relatively unrestricted. Population differentiation was similar to other conifer species. No genetic differentiation between shrub and tree growth forms was observed in Kuanshan population. However, a significat genetic differentiation existed betweet tree-form Nanhuchi population and shrub-form Nanhutashanbefeng population in Nanhutashan region.中文摘要----------------------------------------------Ⅰ 英文摘要----------------------------------------------Ⅱ 壹、前言---------------------------------------------- 1 貳、前人研究------------------------------------------ 3 參、材料與方法----------------------------------------12 肆、結果--------------------------------------------- 22 伍、討論--------------------------------------------- 35 陸、結論--------------------------------------------- 46 柒、引用文獻----------------------------------------- 4

    CELLDEX2018

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    Data and code associated with the manuscript: SD Tiegs, DM Costello, MW Isken, G Woodward, PB McIntyre, MO Gessner, E Chauvet, NA Griffiths, AS Flecker, et al. Global patterns and drivers of ecosystem functioning in rivers and riparian zones
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