Demographic expansion of two Tamarix species along the Yellow River caused by geological events and climate change in the Pleistocene.

The geological events and climatic fluctuations during the Pleistocene played important roles in shaping patterns of species distribution. However, few studies have evaluated the patterns of species distribution that were influenced by the Yellow River. The present work analyzed the demography of two endemic tree species that are widely distributed along the Yellow River, Tamarix austromongolica and Tamarix chinensis, to understand the role of the Yellow River and Pleistocene climate in shaping their distribution patterns. The most common chlorotype, chlorotype 1, was found in all populations, and its divergence time could be dated back to 0.19 million years ago (Ma). This dating coincides well with the formation of the modern Yellow River and the timing of Marine Isotope Stages 5e-6 (MIS 5e-6). Bayesian reconstructions along with models of paleodistribution revealed that these two species experienced a demographic expansion in population size during the Quaternary period. Approximate Bayesian computation analyses supported a scenario of expansion approximately from the upper to lower reaches of the Yellow River. Our results provide support for the roles of the Yellow River and the Pleistocene climate in driving demographic expansion of the populations of T. austromongolica and T. chinensis. These findings are useful for understanding the effects of geological events and past climatic fluctuations on species distribution patterns.

[Analysis on Cistanche tubulosa that parasites on different Tamarixs by RAPD].

OBJECTIVE: To study genetic difference of Cistanche tubulosa that parasites on different Tamarixs and give a reference to select host of C. tubulosa. METHOD: Sixteen selected primers by random amplified polymorphic DNA (RAPD) markers were used to analyze genetic distance of C. tubulosa that parasites on eight different hosts. RESULT: Sixty-six point seven percent of the total bands were polymorphic, that proved the genetic diversity level in different C. tubulosa types was relatively high, especially the two that parasites on Tamarix hispida and T. chinensis. Cultural areas had more remarkable influence on genetic distance of Cistanche tubulosa than the hosts, and introduction was helpful to maintain the more genetic diversity in different C. tubulosa types. Genetic difference in different C. tubulosa types was far less than that between different species in Cistanche. CONCLUSION: C. tubulosa types which parasite on different Tamarixs have high genetic diversity.

[Inoculation experiments of Cistanche tubulosa on 8 introduced Tamarix species].

OBJECTIVE: To analyze the inoculation ratio and echinacoside content of Cistanche tubulosa and provide theoretical basis for Tamarix introduction, resource protection and screening of C. tubulosa. METHOD: 8 Tamarix species were introduced in the North China Plain and inoculation of C. tubulosa was conducted on all species. Phenylethanoid glycosides fingerprinting and echinacoside content of C. tubulosa were analyzed by using HPLC. RESULT: The adaptability of 8 Tamarix species were significantly different, phenylethanoid glycosides component of C. tubulosa on T. gansuensis and T. austromongolica were basically identical in contrast to T. chinensis, echinacoside content showed no obvious difference in C. tubulosa plant growing 4 months. CONCLUSION: T. gansuensis and T. Austromongolica are suitable for the host introduction plant of C. tubulosa resource protection and screening in North China Plain.

[The determination of echinacoside and acteoside in herbs of Cistanche tubulosa].

OBJECTIVE: To analyse the echinacoside and acteoside content of Cistanche tubulosa, collected from different hosts and different size of the cultivated, which is compared to the wilding by RP-HPLC method. METHOD: An Agilent Eclipse XDB-C18(4.6 mm x 250 mm, 5 microm) column was used and a mixture of methanol-acetonitrile-1% acetic acid (15:10:75) was used as the mobile phase at a flow rate of 0.6 mL x min(-1). The column temperature was 30 degrees C and the UV detection wavelength was 334 nm. RESULT: The calibration curves of echinacoside and acteoside were in good linearity over the range of 0.904-9.04 microg (r = 0.999 9), and 1.27-12.7 microg (r = 0.999 9) respectively and the average recoveries of echinacoside (and acteoside) were 98.9% (n = 5, RSD 1.9%), and 97.0% (n = 5, RSD 0.97%). CONCLUSION: The method is simple, quick, acurate. In all of the samples, the contents of echinacoside is markedly more than that of acteoside, the content of the two active component in the wilding is higher than that in the planting. The content of sample in the different sizes gradually increase from the big to the small, and the contents of samples collected from the different hosts vary markedly. These results are useful for the quality evaluation of medicinal materials of C. tubulosa.