Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 2015

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Adaptative strategy of leaf traits to drought conditions: Quercus aliena var. acuteserrata forest (The Qinling Mts. China)

Wang M., Wan P., Chai Y., Guo Y., Zhang X., Yue M.

Polish Journal of Ecology

2015

Vol. 63, nr 1

77--87

In a climax community where all species are sharing relatively similar and stable habitat, there are differences in leaf traits between deciduous trees and shrubs and dominant species and companion species, especially in leaf lifespan (LLs). What are the differences of relationships among leaf traits between deciduous trees and shrubs? What are the mechanisms of this phenomenon? Here, we presented a one-year observation and recorded the LLs followed a modified method in a Quercus aliena var. acuteserrata forest in the north slope of the Qinling Mountains, China. We found that (i) Different species in the same stand performed quite differently in their LLs (P <0.005). Average LLs of shrubs was slightly longer (P = 0.05) than that of deciduous trees. (ii) LLs showed a significant negative correlation with specific leaf area (SLA) and leaf nitrogen content (LNC) (P <0.05) in deciduous trees, however, a significant positive correlation with LNC and leaf carbon content (LCC) (P <0.05) was detected in shrubs. (iii) The comparison of the traits between dominant and companion species in arbor layer and shrub layer showed that there was no significant difference in LLs, LCC and LNC, except SLA in arbor layer. Our study indicated that the amount of light, at the community scale, might be a main factor determining the LLs of wood plants in deciduous forest. The difference between trees and shrubs in relationships among leaf traits suggests that deciduous trees and shrubs may take different strategies to adapt to the environment. SLA is likely to be a marker trait to distinguish dominant and companion species in arbor layer of deciduous broad leaved forest

Identification and differentiation of major flavonoids in two kinds of Epimedium extracts and rat plasma by rapid-resolution liquid chromatography combined with time-of-flight mass spectrometry

Lv L., Zhao L., Wang X., Zhang H., Zhu Z., Chai Y., Zhang G.

Acta Chromatographica

2015

Vol. 27, no. 2

331--353

Epimedium pubescens Maxim. and Epimedium koreanum Nakai. are two common and confused species of Herba Epimedii in Chinese Pharmacopoeia 2010 edition. Different species and growing conditions lead to chemical differences between the two species which may result in the improper clinical usage. In this work, a new method based on rapid-resolution liquid chromatography combined with time-of-flight mass spectrometry (RRLC/TOFMS) has been developed for identification and differentiation of major flavonoids in two kinds of Epimedium extract and rat plasma. The compounds were identified effectively based on the accurate extract masses and formulae acquired by RRLC/TOFMS. The fragmentation rules deduced by collision-induced dissociation (CID) were successfully implemented in distinguishing some of the isomers, further validating the results. By using the combined analytical techniques, a total of 40 major flavonoids in extracts of two kinds of Epimedium were identified within 30 min, including 31 common components and 9 characteristic components. After oral administration, three prototype compounds in rat plasma were detected by comparing the constituents measured in vitro with those in vivo, and five metabolites were identified by contrasting the fragmentation rules. The identification and structural elucidation of the chemical constituents provided essential data for further pharmacological and clinical studies on different species of Epimedium.