Analysis of Active Nucleolus Organizing Regions in Polyploid Prairie Cordgrass (<i>Spartina pectinata</i> Link) by Silver Staining

Abstract

Summary Prairie cordgrass has recently gained attention as an important biotic component of stressed ecosystems. This polyploid species is distributed broadly across the U.S. More cytogenetic data are needed to investigate how increased ploidy levels influence chromosome changes and gene expression in order to understand the formation of stable cytotypes. Silver staining is the cytogenetic method commonly used to study the number and distribution of active nucleolar organizing regions (NORs) on chromosomes at metaphase, and the number and size of nucleoli in nuclei at interphase. Intensity and distribution patterns of silver stained NORs (AgNORs) reveal differential ribosomal gene expressions in plants and animals. The purpose of this study is to estimate the number of AgNORs, their locations, and their activities in metaphase chromosomes and to determine heteromorphic variation in size and number of nucleoli within interphase nuclei for tetra-, hexa-, and octoploid prairie cordgrass populations. Increases in mean numbers of AgNORs in each metaphase and interphase cell were observed as ploidy level increases. Although distribution patterns of silver stained NORs at metaphase cells of tetra-and octoploids reflect changes in ploidy, the neohexaploids did not follow the pattern, indicating that active NORs were not stable in early generation of formation of neo-hexaploidy. Collectively, these results suggest that distribution patterns of silver stained NORs in metaphase and number of silver stained nucleoli in interphase cells can be used as markers to detecting chromosome variations within and among ploidy levels and to determine when ploidy levels stabilize in prairie cordgrass.

Sea sandwort from Surtsey: chromosomal evidence of active evolution via wide-hybridization

“…rDNA transcription and rRNA maturation, and ribosome production (McKeown & Shaw 2009). The number of nucleoli in plants has been positively correlated with the ploidy level (Leven 2002;Kim et al 2015).…”

Kajian Poliploidi Ikan Sepat (Trichogaster trichopterus) pada Tiga Ketinggian Tempat Berbeda di Daerah Banyuwangi, Malang, dan Batu dengan Metode Penghitungan Nukleolus

“…Poliploidisasi secara alami terjadi akibat pencemaran perairan, radisasi sinar ultraviolet ataupun akibat hormon berlebihan, sehingga menyebabkan kasus nondisjungsi pada kromosom (Rottmann, Shireman, & Chapman, 1991). Selain itu, ketinggian tempat juga mempengaruhi poliploidi (Diallo, 2015;Ramsey & Ramsey, 2014; Xie-Kui, Cheng-Qi, Zhang, Chen, & Liu, 2008) Silver staining (AgNO3) merupakan metode sitogenetik yang umum digunakan untuk mempelajari jumlah, ukuran dan distribusi dari silver nucleolar organizer regions (AgNORs) saat metafase atau nukleoli pada interfase (Kim, Lee, & Rayburn, 2015).…”

“…Dengan prosedur pewarnaan perak, kita dapat mempelajari variasi maksimum pada AgNOR saat metafase dan nukeloli saat interfase (Kim et al, 2015).…”