Relationships among Genome Size, Environmental Conditions and Geographical Distribution in Natural Populations of NW Patagonian Species of Berberis L. (Berberidaceae)

Abstract

Variation in genome size of 24 populations belonging to 11 NW Patagonian species of Berberis was analysed as a function of the environment and geographical location. The variation showed three levels of discontinuity, two of which corresponded to diploid species (2n 28) while the third corresponded to polyploid species (2n 56). Diploids with DNA content ranging from 1 . 463 pg to 1 . 857 pg included Berberis cabrerae, B. chillanensis, B. montana, B. serrato-dentata and B. bidentata. Diploids with DNA content ranging from 2 . 875 pg to 3 . 806 pg included B. linearifolia, B. darwinii, B. parodii and B. empetrifolia. The genome size of the polyploid species B. buxifolia and B. heterophylla ranged from 5 . 809 pg to 6 . 844 pg. Principal component analysis (PCA) was applied to represent the variability of environmental conditions. The eigenvectors of the principal component axes showed that PC1 discriminates the populations according to rainfall, types of vegetation and geomorphology; altitude and latitude, on the other hand, contribute to PC2 and PC3, respectively. From these results it is concluded: (1) that diploids with lower DNA content grow in high-elevation sites having greater rainfall but lower water availability; (2) diploids with higher DNA content are associated with half-elevation forests where the vegetative period is longer, the water availability is greater and the temperatures are higher; and (3) the distribution pattern of polyploids is considerably wider than that of diploids, which are geographically and ecologically restricted to forest areas. These results suggest that the C-value plays an important role in the ability of the species to adapt to dierent growing conditions. # 2000 Annals of Botany Company

Evolution of Genome size in Hawaiian Endemic Genus Schiedea (Caryophyllaceae)

“…[3]. Genome increase due to polyploidization was shown for Cerastium, another representative of the subfamily Alsinoideae [4], as well as for many other genera from more distant families (e.g., Berberis, [5]; Hordeum, [16]; Veronica, [1]). However different species of Schiedea and Honckenya have similar chromosome numbers.…”

“…Correlations between genome size evolution and ecology or reproductive biology have been shown for some plant genera (e.g., Berberis, [5]; Hordeum, [16]; Veronica, [1]), although the general adaptive role of genome size is still debated as genome size-dependent constraints acting on metabolic efficiency may not exist within seed plants [2]. The absence of a correlation between the relative DNA content of Schiedea species and their reproductive biology, habit or habitat suggests that genome increase in younger Schiedea species has not played a role in their specialization.…”

DNA C‐values and chromosome numbers inFuchsiaL. (Onagraceae) species and artificial hybrids

“…amongst the american species there does not appear to be any obvious correlation between C-value and geographical distribution, and whether there is an ecological or evolutionary relationship with DNa content in Fuchsia is difficult to ascertain. There is variation in DNa amount across geographically different regions (New Zealand and South/Central america), but whether this is correlated with environment, as previously reported in many genera (Grime & Mowforth 1982;Bottini et al 2000;Palomino & Sousa 2000), is unknown as detailed information on the ecology of the species is not readily available.…”

Karyological and Nuclear DNA Variation in Iranian Endemic Muskmelon (Cucumis melo var. inodorus)

“…There is a positive correlation between latitudes and genome size (Bennett 1976, Bottini et al 2000. Bennett (1976) compared the distribution of cereal, pasture and pulse species with varying C-values over the range of northern latitudes where the crops are cultivated.…”