نتایج جستجو برای: stipa hohenackeriana trin
تعداد نتایج: 810 فیلتر نتایج به سال:
مطالعه تغییرات پوشش گیاهی تحت شرایط عدم چرای دام در رویشگاههای مرتعی، از اهمیت ویژه ای برخوردار است. تصور بر این است که حفاظت مرتع از چرای دام موجب گرایش آن به طرف مرحله کلیماکس و بهبود وضعیت مرتع میگردد. قسمت بیشتر مراتع کشور ما در مناطق خشک و نیمه خشک قرار دارد. نوسان و تغییر سال به سال بارندگی از عوامل عمدهای است که پوشش گیاهی را تحت تأثیر قرار میدهد. در سالهای خشک که بارندگی کاهش مییاب...
به منظور درک مکانیسم تنوع زیستی الگوهای اکولوژیکی در اکوسیستمها و پایه ای برای حفاظت و مدیریت تنوع زیستی، تولید و غنای گونهای طی یک سال در مراتع تنگ چنار استان یزد اندازه گیری شد و منحنی پاسخ خصوصیت غنای گونههای گیاهی در امتداد شیب تغییرات تولید بررسی شد. از آنالیز رگرسیون خطی و غیرخطی جهت بررسی رابطه بین غنای گونهای به عنوان متغیر وابسته و تولید به عنوان متغیر مستقل استفاده شد. میزان متوس...
Forage production of rangelands differs during different times of grazing season and in the same month of different years. In range management projects, grazing capacity calculated once during the grazing season, which coincides with the maximum production of rangeland species. This may cause more livestock entry into the rangeland during the grazing season, leading to more degradation. Th...
Feedbacks between plants and soil biota are increasingly identified as key determinants of species abundance patterns within plant communities. However, our understanding of how plant-soil feedbacks (PSFs) may contribute to invasions is limited by our understanding of how feedbacks may shift in the light of other ecological processes. Here we assess how the strength of PSFs may shift as soil mi...
Stipa robusta (= Stipa vaseyi) is a perennial grass found in certain areas of the southwestern United States. It is commonly known as sleepygrass, as horses that ingest this grass may become profoundly somnolent or stuporous for periods of time lasting up to several days. In an attempt to determine the active principle(s), fractionation of a methanolic extract of sleepygrass infected with an Ac...
Plants depend upon both genetic differences and phenotypic plasticity to cope with environmental variation over different timescales. The spatial variation in foliar δ(13)C levels along a moisture gradient represents an overlay of genetic and plastic responses. We hypothesized that such a spatial variation would be more obvious than the variation arising purely from a plastic response to moistu...
An understanding of the factors controlling plant community composition will allow improved prediction of the responses of plant communities to natural and anthropogenic environmental change. Using monitoring data from 1980 to 2009, we quantified the changes in community composition in Leymus chinensis and Stipa grandis dominated grasslands in Inner Mongolia under long-term grazing-exclusion an...
PREMISE OF THE STUDY Stipa breviflora (Poaceae) is one of the dominant species of the desert steppe in the eastern Eurasian grasslands. Simple sequence repeat (SSR) markers were developed for use in genetic diversity studies of this species. METHODS AND RESULTS A total of 1954 potentially polymorphic loci were obtained by comparing transcriptome data of eight different S. breviflora individua...
Triple Refined Indeterminate Neutrosophic Set (TRINS) a case of the refined neutrosophic set was introduced in [8]. The uncertain and inconsistent information which are available in real world is represented with sensitivity and accuracy by TRINS. Better precision is provided in handling indeterminacy; by classifying indeterminacy (I) into three, based on membership; as indeterminacy leaning to...
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