Keywords:
Rheum (plant)
Polygonaceae
Polygonaceae
Rheum (plant)
Polygonum
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Polygonaceae
Rheum (plant)
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Rheum (plant)
Polygonaceae
Polygonum
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Rheum moorcroftianum (Polygonaceae) was recorded for the first time in Kashmir Himalayas region. The species was identified using morphological and molecular (DNA-barcode) data. R. moorcroftianum can be distinguished from the other Rheum species on the basis of absence of stem, 3‒7 or more basal leaves, inflorescence in branched panicle, rachis papilliferous, perianth yellow-white, anthers pinkish-red, and seeds red, 3-winged.
Polygonaceae
Perianth
Rheum (plant)
Eudicots
Panicle
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Rheum neyshabourense Baradaran & Jafari from northeastern Iran (Khorassan Razavi Province) is newly described. It is similar to R. ribes but differs in the number of prominent leaf veins, the position of the joint on the pedicle, fruit shape, epidermal cell shape and the type of stele in the inflorescence axis. A key to Rheum species in Iran is also provided.
Polygonaceae
Rheum (plant)
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Rheum khorasanicum B. Baradaran & A. Jafari is described and illustrated as a new species from NR Iran. It is morphologically very close to R. ribes, both of them belonging to sect. Rheum. Some features that differentiate R. khorasanicum from R. ribes are the presence of bracts, different surface of inflorescence, the pedicle joint position and the epidermal cell shape.
Polygonaceae
Rheum (plant)
Ribes
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Rheum (plant)
Polygonaceae
Polygonum
Magnolol
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Rapid putative radiations of Rheum might be caused by the recent uplifts of the Qinghai–Tibetan Plateau and the quaternary climate oscillations. To better understand the molecular adaptation associated with Rheum radiation, in this study, the adaptive evolution of the chloroplast rbcL gene was analysed using the Phylogenetic Analysis Program. The results showed that two amino acid residues (75F, 203I) were under positive selection. The spatial analysis indicated that the site (75F) was located in the β-sheet of the N-terminal loops involved in subunit interactions in the L8S8 molecule, and the site (203I) was in the α/β-barrel active centre located on the C-terminal domain of the large subunit of Rubisco. These results suggest that potential positive selection in rbcL might have played an important role in the adaption of Rheum species to the extreme environments in Qinghai–Tibetan Plateau regions, and different species lineages might have been subjected to different selective pressures.
Polygonaceae
Rheum (plant)
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مورفولوژی دانه گرده جنس Rheum L. (Polygonaceae) در ایران با استفاده از میکروسکوپ نوری (LM) و میکروسکوپ الکترونی نگاره (SEM) مطالعه شد. دانه‌های گرده در نمای قطبی معمولا دارای تقارن محوری، در دو قطب مشابه، وسه شیاری اند در حالی که در نمای استوایی دایره‌ای شکل‌اند. تزیینات سطح اگزین متغیر است و به شکل‌های با منافذ پراکنده تا منفذ‌دار، میخچه‌های پراکنده (Rh. turkestanicum)، منافذ کشیده، میخچه دار (Rh. ribes) و یا منافذ نوک سوزنی- با تراکم بالایی از میخچه‌ها (Rh. persicum) دیده می‌شوند. بر اساس صفات کمی و کیفی مطالعه شده کلید شناسایی گونه‌های ایران ارایه می‌شود.
Polygonaceae
Rheum (plant)
Ribes
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Polygonaceae
Rheum (plant)
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Citations (3)