نتایج جستجو برای: plant species
تعداد نتایج: 871061 فیلتر نتایج به سال:
شبدرکوهسری یا شبدر کوهستان (trifolium radicosum (boiss. & hohen گونه ای است علفی و چند ساله که در اقلیم سرد مدیترانه ای البرز میانی رشد می نماید. استقرار این گونه در عرصه های کوهستانی سردو برف گیر، مرتفع و شیب دار، باعث حفاظت خاک عرصه مستعد فرسایش گردیده و از اهمیت منحصر بفرد مرتعی و اکولوژیک برخوردار است. شیب تند رویشگاه، تولید علوفۀ قابل توجه، شدت چراو باعث گردیده تا این گونه بشدت در معرض...
Prunus eburnea (Spach) Aitch. & Hemsl. is an endemic plant species of Iran-Afghanestan, which has medicinal and nutritional value and distributed in extensive parts of arid and semi-arid ecosystems of Iran. The aims of this study were to investigate the life forms and chorology of associated perennial plant species and biodiversity indices in 52 habitats. Habitats were divided into ten main reg...
in arid and semi-arid rangelands, grazing as one of the natural or human induced processes has direct and indirect effects on structure and dynamics of plant community and ecosystems. a study was done to analyze the effects of grazing on plant species diversity and plant functional types‘ (pfts) diversity of arid and semi-arid rangelands. we analyzed plant richness and diversity data from 75 sa...
A taxonomic survey was carried out to assess the diversity of plant genetic resources in the Horticultural farm of Bangladesh Agricultural University, Mymensingh. The data were collected during April 2004 to March 2005. A total of 25328 (including unidentified plant species) species were recorded in which trees, shrubs, herbs, climbers and woody grasses were 51.56, 27.60, 7.81, 10.41, and 2.61%...
Ferula stenocarpa from Apiaceae family is a perennial plant with about 2 meters height, which grows in the high temperature of sudanian regions. This research was aimed to investigate the autecology of an endemic plant to Iran, Ferula stenocarpa, in Khuzestan province. Initially, the habitat map was prepared and characteristics of the species habitat including topography, climate, soil properti...
fauna of the the aphid parasitoids at southern parts of the zagros submountains, and their host associations have been investigated. a total of 24 parasitoid species were identified in association with 30 aphids on 36 host plant species, representing more than 80 tritrophic associations (parasitoid-aphid-plant). aphidius avenae haliday is newly reported from iran. generally, the area of souther...
based on the latest records of typhlops vermicularis merrem, 1820 from iran, this species is distributed in the northern and southern regions of the country. in this study, new records of typhlops vermicularis are presented and it is shown that distribution range of this species is extended towards the eastern and western iran, and according to the new distribution map, it can be assumed that t...
The origin of new homoploid species via hybridization is theoretically difficult because it requires the development of reproductive isolation in sympatry. Nonetheless, this mode is often and carelessly used by botanists to account for the formation of species that are morphologically intermediate with respect to related congeners. Here, I review experimental, theoretical, and empirical studies...
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