[Morphological and TLC identification on Tibetan medicine Asteris Flos].

Tibetan medicine Asteris Flos is the flowers of Aster souliei, A. flaccidus, and A. asteroides, with the function of clearing away heat and toxic matter, relieving cough, and removing phlegm. In order to control the quality of Asteris Flos, the morphological and chemical methods were established for identification of three origins. The morphological features of three species were described and photographed, and the microscopic characteristics of three drug powders were also described in detail and pictured. The results showed that three origins of Asteris Flos could be easily distinguished by their macro- and micro-morphologic features, and a key for distinguishing the three origins was given. Moreover, a TLC method, with apigenin-7-O-ß-D-glucurono pyranoside and chlorogenic acid as chemical references, was also established for the identification of three origins. The results showed that the TLC chromatograms of the flowers of A. souliei and A. flaccidus were very similar, but different from that of A. asteroides. The established macroscopic, powder microscopic and TLC methods for identification of three origins of AF were simple, accurate, and reproducible, and also effective and easy to operate.

Cytotype distribution at a diploid-hexaploid contact zone in Aster amellus (Asteraceae).

BACKGROUND AND AIMS: The present study aims to assess the diversity and distribution of cytotypes of Aster amellus in central and eastern Europe, contributing with data to improve understanding of the evolutionary dynamics of the contact zone between diploids and hexaploids of this polyploid complex. METHODS: Large-scale cytotype screening of 4720 individuals collected in 229 populations was performed using 4',6-diamidino-2-phenylindole (DAPI) flow cytometry. Fine-scale cytotype screening was performed in the mixed-ploidy population. Reproductive variables, such as number of florets per flower head, seed set and seedling emergence, as well as ploidy level of seeds and seedlings were recorded in this population. KEY RESULTS: The diploid-hexaploid contact zone is large and complex, reaching the Czech Republic in the west, Austria in the south, Poland in the north-east and Romania in the extreme east of the surveyed areas. Most populations presented only one cytotype, either diploid or hexaploid. In several areas of the contact zone both cytotypes were found to grow in parapatry. One mixed-ploidy population of diploids and hexaploids was detected for the first time, but no signs of hybridization were detected. In this population, diploids had a significantly lower reproductive success, and significantly higher production of intercytotype offspring, being in reproductive disadvantage in comparison with hexaploids. CONCLUSIONS: The contact zone of diploid and hexaploid A. amellus in central and eastern Europe seems to be highly dynamic and diffuse, with both primary and secondary contacts being possible. The obtained results suggest the origin of hexaploids through diploids, overall supporting previous hypotheses that this species is autopolyploid. Data from the only mixed-ploidy population detected so far suggest that the minority cytotype exclusion is an important evolutionary mechanisms driving the prevalence of single-cytotype populations, and thus contributing to the current distributional patterns of the cytotypes of A. amellus.