نتایج جستجو برای: koeleria cristata
تعداد نتایج: 446 فیلتر نتایج به سال:
فنولوژی پنج گونه مرتعی festuca ovina, koeleria macrantha, koeleria phleoides, melica cupani, melica jacquemontii در ایستگاه تحقیقات مراتع همند آبسرد در 70 کیلومتری شرق تهران در سالهای 82 تا 84 مورد مطالعه قرار گرفت. در این مطالعه از هر گونه تعداد20 پایه انتخاب و در فصل رویش هر هفته یکبار و در فصل غیر فعال هر 15 روز یکبار، از مراحل شروع رویش و رشد رویشی، ظهور ساقه گلدار، ظهور خوشه یا سنبله، ش...
Parental body mass changes during the nesting period were analysed for Thekla Larks, Galerida theklae, and Lesser Short-toed Larks, Calandrella rufescens. Body mass of female Thekla Larks declines from the start of incubation until the chicks fledge; laying date, interpreted as the number of renesting attempts, also has a negative effect. Body mass of female Lesser Short-toed Larks was not rela...
Communication depends on reliability. Yet, the existence of stable honest signalling presents an evolutionary puzzle. Why should animals signal honestly in the face of a conflict of interest? While students of animal signalling have offered several theoretical answers to this puzzle, the most widely studied model, commonly called the 'handicap principle', postulates that the costs of signals st...
Evolution of diabroticite rootworm beetle (Chrysomelidae) receptors for Cucurbita blossom volatiles.
The diabroticite rootworm beetles coevolved with plants of the family Cucurbitaceae as demonstrated by their feeding dependence on the tetracyclic triterpenoid cucurbitacins. These beetles also exhibit strong attraction to phenylpropanoid volatile components of Cucurbita blossoms. A mixture of 1,2,4-trimethoxybenzene, indole, and (E)-cinnamaldehyde, all blossom components, is highly attractive ...
Relationships within and between the principally North American, malvaceous genera A noda and Periptera are assessed through analysis of chromosomal and hybridization data. Chromosome numbers are reported for ten species of Anoda and one of Periptera, and observations on meiosis in hybrid and non hybrid plants are presented . The results indicate: I) that Anoda and Periptera are closely related...
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