نتایج جستجو برای: venturia canescens
تعداد نتایج: 892 فیلتر نتایج به سال:
387 W ith his usual foresight, J.B.S. Haldane argued nearly 50 years ago that 'a non specific parasite is a powerful competitive weapon' 1. One species can be a superior competitor simply by harbouring and transmitting a pathogen to a more vulnerable species. This is 'apparent' competition, which is mediated via a shared pathogen, and contrasts with 're-source' competition, in which there can b...
Seven pyrrolizidine alkaloids (PAs) have been isolated from Lithospermum canescens and their structures determined by spectroscopical methods. Besides the known lycopsamine, O7-acetyl-lycopsamine and O7-acetylintermedine four new PAs were found. Their structures are O7-(3-hydroxy-3-methyl-butanoyl)-O9-(+)-trachelanthoyl-heliotridine (= O7-(3-hydroxy-3-methyl-butanoyl)-rinderine = canescine), O7...
ارایهی روشی دقیق، سریع و کم هزینه برای تعیین تولید گیاهان مرتعی یکی از اهداف بوم شناسان به ویژه مرتعداران است که همیشه علاقهمند به دانستن میزان تغییرات این ویژگی گیاهی هستند. هدف اصلی این تحقیق، تعیین روابطی بین متغیرهای سطح تاجپوشش، حجم و ارتفاع با تولید گونههای atriplex canescens، acanthophyllum squarrosum، lactuca orientalis، astragalus meshedensis و stipa barbata در مراتع جنوب بیرجند ...
As plants have been shown to accumulate organic compounds from contaminated sediments, there is a potential for long-lasting ecological impact as a result of contaminant accumulation in riparian areas of wetlands, particularly the accumulation of non-biodegradable contaminants such as perfluorooctanoic acid (PFOA). In this study, commonly found riparian wetland plants including reeds, i.e., Xan...
Two skeletons of the large compsognathid Sinocalliopteryx gigas include intact abdominal contents. Both specimens come from the Jianshangou Beds of the lower Yixian Formation (Neocomian), Liaoning, China. The holotype of S. gigas preserves a partial dromaeosaurid leg in the abdominal cavity, here attributed to Sinornithosaurus. A second, newly-discovered specimen preserves the remains of at lea...
While Hymenoscyphus fraxineus causes dieback of the European ash (Fraxinus excelsior), flowering ash (F. ornus) appears resistant to the pathogen. To date, contributions of endophytic fungi to host resistance are unknown. The following hypotheses were tested: (i) endophytic fungi enhance the resistance of F. excelsior to the pathogen; (ii) resistance of F. ornus relies on its community of endop...
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