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Objective: A method for the simultaneous determination of 6 plant growth regulator (PGR) residues in bean sprout was developed by ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). 6-Benzylaminopurine, isopentennyladenine, 4-chlorophenoxyacetic acid, 4-fluorophenoxyacetic acid, indole-3- acetic acid and indole-3-butyric acid were concerned., Methods: Bean sprout samples were extracted by acetonitrile and QuEChERS extraction kit, purified by C18 powers. After centrifugation, the sample liquids was diluted 10 times by ultrapure water. The chromatographic analysis was carried out on an waters acquity UPLC BEH C18 column( 100 mm x 2.1 mm, 1.7 microm). The analyzer confirmed and quantified by mass spectrum of triple quadrupole in the multiple reaction monitoring (MRM) mode and quantified by matrix-matched external standard method., Results: The calibration curves showed good linearity in each range with correlation coefficients greater than 0.998. 3 levels spiked recoveries were carried out using blank bean sprout extraction as substrate, the recoveries ranged from 84.2% to 107.5%, the relative standard deviations (RSDs) ranged from 3.08% to 12.71%. The qualitative limits of detections (S/N = 3) were 0.03-3.0 microg/kg and the quantitative limits(S/N = 10) were 0.1-10.0 microg/kg for the 6 PGRs., Conslusion: The method is simple and easy to operate, with less organic reagent, high sensitivity and good stability. It is suitable for the detection of 6 kinds of plant growth regulators in bean sprouts.

Objective: This study aimed to investigate the diversity of endophytic bacteria isolated from rice seeds, and screen indole acetic acid secrecting srtains., Method: Conventional culture-dependent methods were used to isolate the endopytic bacteria from rice seeds. Phylogenetic analysis was done based on partial 16s rRNA gene sequences. The ability to indole acetic acid secretion of tested strains was analyzed qualitatively and quantitatively by colorimetry., Result: In total 66 isolates were identified as belonging to 26 species of 15 genera of 5 phyla. Of them 26 strains were chosen to test indole acetic acid secretion. Four isolates had more ability of indole acetic acid secretion; they belonged to the genera of Staphylococcus, Rhizobium, Microbacterium and Methylobacterium., Conclusion: The endophytic bacteria in rice seeds are diverse. Some of them could produce indole acetic acid.

The changes in three endogenous hormones, phytohormones gibberrelic acid (GA3), indoles-3-acid (IAA) and abscisic acid (ABA), were studied around germination and under tress of different density of Pb2+ between two species of Ammopiptanathus. It was found that (1) around germination, in Xinjiang Ammopiptanthus the rate IAA decreased 77.80%, and the rate of ABA decreased 98.90%; and in Mongolia Ammopiptanthus the rate of IAA decreased 75.80%, the rate of ABA decreased 66.20%, and the GA3 contents in both had no big change. (2) With the increase in Pb2+ concentration (20-1 500 mg x L(-1)), the IAA decreased significantly; and only under the high density (more than 1 000 mg x L(-1)) of Pb2+, the GA3 was affected by it; the ABA did not change regularly. So the three endogenous hormone levels of Mongolia Ammopiptanthus were higher than those of Xinjiang Ammopiptanthus. (3) the distributions of Pb2+ in Ammopiptanthus seedlings are the root > stems > leaves. (4) the stress of high concentration of Pb2+ damages irreversibly the leaf cells of Ammopiptanthus. This study can provide the basis of reference data for further research on the growth characteristics, resilience and the mechanism of specific broad-leaved evergreen shrubs-Ammopiptanthus in desertification area.

The plant growth promoting bacteria are closely associated to plant. The bacteria are used to adhering to plant rhizoplane, promoting plant growth by fixing nitrogen from atmosphere, secreting stimulating substances or producing antagonistic to plant pathogens. It was indicated that the biological nitrogen fixation played an important role in plant growth promoting function. In fact, it was verified recently by overall research that IAA does it. Therefore research of IAA production and biosynthetic pathway of plant growth-promoting bacteria is much more important. The various ways of IAA production indicated the strong or weak promoting function of bacterium to plants in general. The purpose of this paper is to determine whether IAA exists in cultured medium of Klebsiella axytoca SG-11 and biosynthetic pathway of IAA, in order to opimize cultural conditions for IAA production. Klebsiella axytoca SG-11 is a plant growth promoting bacterium, isolated from rice rhizoplane, which can fix nitrogen. The supernatant of SG-11 cultured medium determined by HPLC showed that 47.4 mg/L of IAA existed in LB medium and 1.2 mg/L of IAA, in basal medium. IAA in metabolite was identified by GC/MS as well. The intermediate determination of tryptamine, indole-3-acetamide, tryptophol and indole-3-acetonitrile indirectly indicated that IAA was biosynthesized in a pathway of indole-3-pyruvic acid. Meanwhile, tryptophol in metabolite of SG-11 was verified by GC/MS. The direct intermediates of indole-3-pyruvic acid and indole-3-acetaldehyde in the pathway can not be determined, because both are unstable under normal condition. As reversible conversion existed between indole-3 pyruvic aldehyde and tryptophol, the presence of tryptophol also proved the pathway of indole-3-pyruvic acid in the synthesis of IAA by Klebsiella axytoca SG-11. The results laid basis for further research of plant growth-promoting function of the bacterium.

Immuno-gold localization of IAA in cells of the graft union in the explant internode graft of Cucurbita pepo/Cucurbita moschata were investigated with electron microscopy. In parenchyma cells near the graft union, the gold particles were mainly accumulated in nucleus, plastid and endoplasmic reticulum, while no gold particles was detected in Golgi body, mitochondrion, cell wall and vacuoles. In the differentiating xylem element, the gold particles were labeled in secondary wall and cytoplasm. In the sieve element gold particles were found in the sieve plate, sieve pore and cytoplasm. There was a dense label of the gold particles in the companion cell. The role of IAA in the differentiation of the vascular elements was discussed.

A method for the direct determination of auxins, indole acetic acid (IAA), indole-butyric acid (IBA) and naphthylacetic acid (NAA), by gas chromatography with wide-bore capillary column is described. The gas chromatographic conditions were as follows: HP-1 capillary column, 5 m x 0.53 mm i.d., 2.65 microns film, the column temperature 180 degrees C, the temperature of injector 250 degrees C, the temperature of FID detector 260 degrees C, carrier gas: N2 20 mL/min and dibutyl phthalate was used as internal standard. All components and internal standard were separated in 3 min. The relative standard deviations were from 0.61% to 1.14%. The method is simple, rapid, sensitive, good reproducible and satisfactory.

Objective: To study the plant hormones produced by 5 species of endophytic fungi isolated from medicinal plants and to illustrate the mechanism on endophytic fungi stimulating the growth of plants., Methods: Extracting plant hormones from mycelia and its culture solution with organic solvent, and detecting them by HPLC., Results: One or more plant hormones [GA3 (Gibberellin), IAA (Indoleacetic acid), ABA (Abscisic acid), Z (Zeatin), ZR (Zeatin riboside)] were detected from the mycelia and its culture solution., Conclusions: The plant hormones produced by the endophytic fungi are important materials that may be used to reveal the mechanism of endophytic fungi stimulating the growth of medicinal plants (Orchidacea).

It is important for separation and determination of plant growth regulators in the research of plant physiology. A study of the separation of five plant growth regulators, such as abscisic acid (ABA), gibberellic acid (GA), indole-butyric acid (IBA), indole acetic acid (IAA) and naphthaleneacetic (NAA) by micellar electrokinetic chromatography (MEKC) is presented. The effects of pH, SDS concentration, applied voltage and organic additives on migration behavior were investigated. Results showed that satisfactory separation was achieved on optimization of electrophoretic condition: 80 mmol/L SDS, 10 mmol/L borate-phosphate, 5% isopropanol, 18 kV applied voltage, pH 8.0. The SDS concentration and organic additives played an important role in separating plant growth regulators, and the applied voltage and pH gave less effect. The detection limit of ABA, GA, IBA, IAA and NAA were 5.0 x 10(-3), 3.0 x 10(-3), 5.8 x 10(-4), 1.5 x 10(-4) and 1.4 x 10(-4) g/L respectively. Increasing of the SDS concentration or organic additives would change separation factor (alpha) and result an improvement of the resolution of difficult separation pairs ABA-GA and IAA-NAA.