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    • The three Japanese Nuphar species were well distinguished by

    2020-07-27

    The three Japanese Nuphar species were well distinguished by patterns of allele frequencies and PCO analysis (Table 2, Fig. 3). Although N. japonica had species-specific Cy3 carboxylic acid (non-sulfonated) with low frequencies, N. oguraensis and N. subintegerrima had diagnostic loci and were distinguishable. Although a recent taxonomic study of Nuphar worldwide treated N. subintegerrima as a synonym of N. japonica (Padgett et al., 1999, Padgett et al., 2002), the present results indicate that these two species differed in genetical features. Several isozymes in our study (MDH, PGI and TPI) revealed duplicated loci (Fig. 2). Isozyme duplication has also been reported in isozyme studies of N. pumila var. ozeensis (Miki) H.Hara and intermediate plants, identified as “N. subintegerrima” (, Murayama et al., 1998). discussed that intermediate populations of Nuphar in Japan are of hybrid origin based on allozyme data of in which enzyme loci of an intermediate population are duplicated. However, our allozyme analysis revealed that isozyme duplication was not restricted to intermediate plants, but also occurred in MDH, PGI and TPI in N. japonica, N. oguraensis and N. subintegerrima. Furthermore, these isozymes were also duplicated in N. pumila (Shiga and Kadono, 2007a). Although the Nuphar species have been considered diploid (Langlet and Søderberg, 1927, Okada and Tamura, 1981), these isozyme duplications suggest that sect. Nuphar is genetically polyploid. It is probable that these duplications occurred early in the evolution of the genus Nuphar.
    Acknowledgments
    Introduction Understanding the characteristics of the Amazonian Dark soils “Terras Pretas de Índio” (TPIs) is of ecological importance, because the TPI soils represent a residue-based model for tropical sustainable agriculture (Sombroek et al., 2003, Neves et al., 2003, Cohen-Ofri et al., 2006, Cohen-Ofri et al., 2007, Falcão et al., 2003, Glaser, 2007). The TPI sites are identified by the presence of ceramics and by their deep black horizons, generally down to 1m in depth (Fraser et al., 2011). The dark color comes from the high content of black carbon (BC), which are here defined as stable charcoal particles present in the terrestrial ecosystems (Lian et al., 2006, Liang et al., 2008). In the case of the TPI soil, the black carbon is pyrogenic, produced by the Indians when burning residues. Almost no black carbon or ceramics are detectable in immediately surrounding soils, already below 20cm in soil depth (Glaser et al., 2001). The TPI soils sequester up to 70 times more carbon than the surrounding soils, and it is chemically and microbially stable (Glaser et al., 2001, Steiner et al., 2004). Consequently, the microbial community in the TPI is different from those in the surrounding soils (Grossman et al., 2010, Glaser and Birk, 2012). The TPI pyrogenic black carbon (TPI-BC) is made of sp2-ordered carbon nanocrystallites with lateral dimensions of La∼3–8nm (Jorio et al., 2012, Ribeiro-Soares et al., 2013). Despite a structural complexity, the TPI-BC dimensionality (La) has been investigated as a critical parameter defining the stability vs. reactivity properties of the soil (Jorio et al., 2012, Ribeiro-Soares et al., 2013, Archanjo et al., 2014, Archanjo et al., 2015). To be able to reproduce charcoal structures similar to the TPI-BC, for the use as a soil conditioner, it is necessary to understand whether the TPI-BC structure (mostly La) found today was generated by the char and burning, or whether the time exposure to complex physical, chemical and biological degradation played a role. Some authors are discussing how the microbial communities inhabiting the soil may influence its structure (Kabir et al., 1998, Oehl et al., 2005, Talbot et al., 2008, Eilers et al., 2012). While the elemental composition of the TPI has been largely studied (Glaser and Birk, 2012, Schaefer et al., 2004, Kern and Kampf, 2005, Cunha et al., 2009), few works addressed the microbiological composition (Grossman et al., 2010, Glaser and Birk, 2012).