Contribution to the taxonomy and phylogeny of Sarcocapnos DC. (Fumariaceae)

Abstract

Abstract. To solve problems concerning the status of the taxa described in the genus Sarcocapnos, we have conducted a study using morphological, pollen morphology (light microscopy), cytogenetic and molecular techniques. Focusing on the last technique, we have sequenced ITS-1 and ITS-2 of nuclear rDNA. The species differ basically according to 5 morphological traits (leaf shape, flower spur, corolla colour, corolla size, and crest of the stigmatic surface). The cytogenetic analyses indicated n ¼ 16 to be the standard chromosome number. The ITS analyses showed that the genus is monophyletic, defining two main well-supported clades, one containing S. saetabensis and S. enneaphylla, and one containing the rest of the species. In this second clade, S. speciosa, S. pulcherrima, and S. baetica subsp. ardalii are related, as are S. integrifolia, S. crassifolia subsp. crassifolia, and S. crassifolia subsp. atlantis; S. baetica subsp. baetica forms a trichotomy with the foregoing groups. S. speciosa is shown to be a species separate from S. crassifolia subsp. crassifolia, as in the case of S. baetica with respect to S. integrifolia. Palynologically, the parameters used enabled us to establish clear differences between the taxa, often corroborating the macromorphological and genetic data. The flower spur has been reduced several times in different groups of the genus, for which the classifications established on the basis of this trait are paraphyletic.

Concerted evolution of satellite DNA in Sarcocapnos: a matter of time

“…Several studies link phylogeny with satellite DNA divergence both in plants (Schmidt and Kudla 1996;Gao et al These results are compatible with molecular phylogeny of the genus Sarcocapnos based on nuclear internal transcribed spacer (ITS) sequences (Salinas et al 2003). The ITS analyses defined two main clades, one containing S. saetabensis and S. enneaphylla, and one containing the rest of the species.…”

“…In fact, we found that this satellite DNA is genus-specific and, as such, it recently originated according to the recent diversification of the genus Sarcocapnos. Assuming a mean rate of change in plant nuclear DNA of 0.6% per site per million years (Gaut 1998) and using nuclear ITS mean distance estimates data of Salinas et al (2003), we might estimate the origin of this genus at about 7 million years ago (mya) and the diversification and differentiation between some species pairs at less than 0.5 mya. Figure 2 summarizes the ITS data in relation to the phylogeny of the group and the satellite-DNA data.…”

“…All seven species are chasmophytes inhabiting overhanging cliffs with reduced population sizes and reduced number of disjunct populations, this ensuring the lack of gene flow between populations Salinas-Bonillo and Suárez-Santiago 2002). Moreover, all species show a high interspecific differentiation with strong reproductive isolation barriers (Lidén 1986 (Salinas-Bonillo and Suárez-Santiago 2002;Salinas et al 2003). Four of these species (S. baetica, S. integrifolia, S. pulcherrima and S. speciosa) show a narrow distribution area restricted to the Betic Mountains in the south of Iberian Peninsula.…”

X-ray Free Electron Lasers

“…Recently, several techniques have been proposed for achieving even shorter pulse durations. They rely on three different approaches: (i) selection of single radiation spikes employing the statistical properties of the radiation [50], (ii) use of energy-chirped electron bunches [51,52] and (iii) local energy modulation of the electron beam by a strong optical laser pulse [38,[53][54][55].…”

“…If a very short optical pulse is used, with only a few cycles, and a carrier-envelope phase adjusted such that the peak electric field coincides with the envelope peak, a strong local energy modulation is imposed on the electron beam, larger than the FEL bandwidth. Therefore, the FEL undulator can be tuned such that it amplifies only within a small fraction of the optical cycle and produces ∼0.3 fs x-ray pulses [38,53,54]. This method can be modified by adding a magnetic dispersion section enhancing the electron density periodically at the frequency of the optical laser [55].…”