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Symbiotic relationships with microbes may influence how plants respond to environmental change. In the present study, we tested the hypothesis that symbiosis with the endophytes promoted salt tolerance of the native grass. In the field pot experiment we compared the performance of endophyte-infected (E+) and endophyte-uninfected (E−) Leymus chinensis, a dominant species native to the Inner Mongolia steppe, under altered neutral and alkaline salt stresses. The results showed that under both neutral and alkaline salt stresses, endophyte infection significantly increased plant height, leaf length and fibrous root biomass. Under neutral salt stress, endophyte infection decreased Na+ content and Na+/K+ ratio (p=0.066) in the leaf sheath while increased Ca2+ and Mg2+ content in the rhizome. Under alkali salt stress, endophyte infection tended to increase K+ content in the fibrous root, enhance Mg2+ content in the fibrous root while reduce Na+/K+ ratio in the leaf blade in the 100 mmol/L alkali salt treatment. Although endophyte-infected L. chinensis cannot accumulate Na+ high enough to be halophytes, the observed growth promotion and stress tolerance give endophyte/plant associations the potential to be a model for endophyte-assisted phytoremediation of saline-alkaline soils.

A pharmacokinetic study on enrofloxacin (ENR) following different administration regimes (i.e. intramuscular, oral and bath administrations) was carried out for the Chinese mitten-handed crab (Eriocheir sinensis) at 17 °C water temperature. Muscle and hepatopancreas samples were collected at each sampling time of 1 and 10 min and 0.5, 1, 2, 8, 16, 24, 48, 72 and 168 h for intramuscular administration and 0.25, 0.5, 1, 2, 4, 6, 8, 12, 24, 48, 72 and 168 h for oral and bath administration. The levels of ENR and ciprofloxacin (CIP) were simultaneously determined (n=5) by high-performance liquid chromatography. The results showed that similar absorption and elimination patterns of ENR level in muscle and hepatopancreas were observed for oral administration and bath treatment; however, the trend in ENR level changes in muscle and hepatopancreas after intramuscular administration was quite different from oral and bath treatments. Meanwhile, the level of ENR in hepatopancreas was much higher than that in muscle for the same administration regimes. The concentration–time data were analysed with the Practical Pharmacokinetics Program (3P97), and the kinetic profiles of ENR in the hepatopancreas and muscle conformed to two-compartment models. The absorption and elimination of ENR in hepatopancreas for bath treatment were faster than those for oral and intramuscular administrations. However, the pattern was quite different in muscle. The fastest absorption and elimination of ENR in muscle were seen for intramuscular administration.

The aim of this study was to reduce the loss of preliminary treatment of sample such as deriva-tives and emulsification,to enhance the maneuverability and accuracy of method,to promote the in stabil-ity of detection.Residues of pentachlorophenol and its sodium salt in edible tissues of crucian,freshwater shrimp,cod and chinese mitten crab were determined by gas chromatography using internal standard method.Such factors as derivation method,Whether n-hexane was blowed or not for pentachlorophenol and its sodium salt were compared in this paper.Moreover,the chromatographic conditions were surveyed and optimized for detection of the residues of pentachlorophenol and its sodium salt in edible tissues.The target compounds were first extracted two times with n-hexane in an acidic medium,and then back ex-tracted with potassium carbonate solution.The extract was derived with acetic anhydride,and the deriva-tive was extracted with n-hexane.The HP-5MS(30 m×0.32 mm×0.25 μm) column and the micro-cell elec-tron capture detector was used for the determination.This method chooses 2,4,6-TBP as internal standard substance.The working curves were linear(R2=0.9996) in the range of 0.2-20.0 μg/L.When spiked with 2.0,5.0,10.0,50.0 μg/kg of pentachlorophenol and 50 μg/kg of 2,4,6-tribromophenol,the average recov-eries were 85.8%-109.0% and the RSD were 0.8%-9.3%.The detection limit was 0.6 μg/kg.