Leaf physiological traits of plants from the Qinghai-Tibet Plateau and other arid sites in China: Identifying susceptible species and well-adapted extremophiles.

Extreme environments, such as deserts and high-elevation ecosystems, are very important from biodiversity and ecological perspectives. However, plant physiology at those sites has been scarcely studied, likely due to logistic difficulties. In the present study, leaf physiological traits in native plants were analyzed from arid zones across an elevational transect in Western China, from Turpan Basin to the Qinghai-Tibet Plateau (QTP) at Delingha. The aim of this study was to use leaf physiological traits to help identifying potentially threatened species and true extremophiles. Physiological measurements in the field, and particularly in situ measurements of gas exchange and chlorophyll fluorescence, have been determined to be useful to determine the current state of plants at a given environment. Using this approach plus a combination of leaf traits, several species performing particularly well at the QTP were identified, e.g. Hedysarum multijugum, as well as at Manas drylands, e.g. Peganum harmala and Setaria viridis. On the other hand, several species showed marked signs of severe stress, in particular a very low photosynthetic rate over its potential maximum, as well as other negative traits, like low water and/or nitrogen-use-efficiency, which should be considered in conservation plans. Interestingly, all C4 species studied except Setaria viridis were among the most stressed species. Despite their higher water use efficiency and drought-tolerance reputation, they presented a much larger photosynthesis depression than most C3 species. This is an intriguing and interesting observation that deserves further studies.

[Effect of Different Locations and Genotypes on Yield and Accumulation of Bioactive Constituents in Salvia miltiorrhiza].

Objective: The root yield and active constituent contents were analyzed from four Salvia miltiorrhiza cultivars grown at three different locations( Zhuyang, Changqing, and Taian, Shandong Province) to determine the influence of environmental conditions and cultivars. . Methods: Phenolic acids and tanshinones were analyzed by HPLC method. Total phenolic acids content were analyzed by FolinCiocalteu method. Klason method was used to determine the content of lignin. Results: The root yield and the active constituent contents were significantly affected by different environments and cultivars of Salvia miltiorrhiza. The root yield was negatively correlated with active constituent contents. Salvia miltiorrhiza of Zhuyang location had the highest active constituent content, but it had the lowest root yield. Salvia miltiorrhiza of Taian location had the lowest active constituent contents, while it had the highest root yield. Salvia miltiorrhiza of Changqing location had relatively higher bio-yields of phenolic acids and tanshinones, which made it suitable for Salvia miltiorrhiza cultivation. Furthermore, compared with three other cultivars,105 cultivar could remain the salvianolic acid B stable, which indicating that 105 cultivar was possible related to resistances. Conclusion: The research provides a theoretical basis for the selecting of the optimal cultivar and the optimal environmental condition.