[Effects of Conservation Tillage on Herbicide Residues in Maize Field Soil].

It is well known that conservation tillage can improve soil quality, such as soil organic matters. However, limited information on the conservation tillage impacts on pesticides has been reported, which is important to food security. To explore the specific effects of conservation tillage on herbicide residues in soils, parallel soil samples from seven sites under traditional tillage and conservation tillage were collected, respectively, in Jilin Province, Northeast China. The soil properties and characteristics of three herbicides(acetochlor, atrazine, and MCPA-Na) were measured. The results showed that conservation tillage significantly increased total organic carbon(TOC) content, soil water content, and the average particle size of soil aggregates[(2.1±0.1)%, (19.1±1.2)%, and (82.2±3.0) µm increased to(2.9±0.3)%, (22.3±1.5)%, and (97.2±4.2) µm, respectively]. The results also showed that different herbicides were correlated with different soil properties. For example, TOC content and soil water content were positively correlated with atrazine, whereas micro-aggregate content was negatively correlated with acetochlor. Therefore, the effects of conservation tillage on the three herbicide residues were different. For instance, conservation tillage significantly increased the residual amount of atrazine[from(3.8±0.3) ng·g-1 to (17.7±3.0) ng·g-1] in the Dongfeng site by increasing TOC content, whereas it significantly reduced the residual amount of acetochlor[from (50.6±10.3) ng·g-1 to (9.2±2.5) ng·g-1] in the Dehui site by increasing the average particle size of soil aggregates. Generally, this study suggests conservation tillage indeed affected herbicide residues in soils by affecting soil properties. However, the influence of conservation tillage on herbicide residue was dependent on the types of herbicides due to the complex effects of different soil properties on herbicide migration and degradation.

Induced defense and its cost in two bryophyte species.

PREMISE: Current knowledge about defense strategies in plants under herbivore pressure is predominantly based on vascular plants. Bryophytes are rarely consumed by herbivores since they have ample secondary metabolites. However, it is unknown whether bryophytes have induced defenses against herbivory and whether there is a trade-off between growth and defense in bryophytes. METHODS: In an experiment with two peatland bryophytes, Sphagnum magellanicum Brid. and S. fuscum (Schimp.) H. Klinggr., two kinds of herbivory, clipping with scissors and grazing by mealworms (Tenebrio molitor L.) were simulated. At the end of the experiment, we measured growth traits, carbon-based defense compounds (total phenolics and cellulose) and storage compounds (total nonstructural carbohydrates) of these two Sphagnum species. RESULTS: Grazing but not clipping increased total phenolics and C:N ratio and reduced biomass production and height increment. A negative relationship between biomass production and total phenolics was found in S. magellanicum but not in S. fuscum, indicating a growth-defense trade-off that is species-specific. Grazing reduced the sugar starch content of S. magellanicum and the sugar of S. fuscum. Either clipping or grazing had no effect on chlorophyll fluorescence (including actual and maximum photochemical efficiency of photosystem II) except that a significant effect of clipping on actual photochemical efficiency in S. fuscum was observed. CONCLUSIONS: Our results suggest that Sphagnum can have induced defense against herbivory and that this defense can come at a cost of growth. These findings advance our knowledge about induced defense in bryophytes, the earliest land plants.

[Simulation of multimedia fate of phenanthrene in the Yangtze estuary].

A Level III fugacity model is used to simulate the concentration distribution of phenanthrene in air, water, sediment and plants in the Yangtze estuary. Based on simulation results, transfer fluxes among-phase are calculated, and also, the key model parameters are determined by means of sensitivity analysis. The results indicated that the advection of air is the main source of phenanthrene in this area, while the main disappeared way from the study region is the advection of air and water. The degradation of phenanthrene in air is the most and the degradation in sediment is the least. The air is the major store of phenanthrene, where phenanthrene was found accounts for 86.36% of the total amount, however, the phenanthrene concentrations is only 0.5 x 10(-7) mol x m(-3). The phenanthrene concentrations are higher in sediment and plants which are 1.5 x 10(-6) mol x m(-3) and 4.4 x 10(-6) mol x m(-3), respectively. The distribute coefficient and the sedimentation rate of the phenanthrene control the distribution of the phenanthrene in each medium.

[The follow-up study on P50 auditory sensory gating in naïve schizophrenia].

OBJECTIVE: To understand the variations of sensory gating P50 in naïve schizophrenia during follow-up and the relations with positive and negative symptom scale (PANSS). METHODS: The data of auditory evoked potential P50 were recorded by USA Nicolet Brova instrument from 58 naïve schizophrenia patients (Sch) and 108 normal controls (NC) at baseline, Months 1, 2 and 3 after treatment. And a simultaneous assessment of PANSS was made. RESULTS: (1) At baseline, as compared with NC, Sch group had a sensory gating deficit, reflected by a higher S2/S1 (Cz: NC: 0.43 (0.27, 0.58); Sch: 0.77 (0.58, 1.04); Z = -9.23, P < 0.01), lower S1-S2 (Cz: NC: 2.65 (1.55, 4.79) microV; Sch: 0.92(-0.13, 2.32) microV; Z = -6.01, P < 0.01) and decreased more (1-S2/S1) (Cz: NC: 0.57 (0.43, 0.73); Sch: 0.23 (-0.04, 0.42); Z = -10.61, P < 0.01). (2) During follow-up, Sch group still had a sensory gating deficit. Compared with NC, Sch group had a more elevated S2-P50 amplitude, higher S2/S1, lower S1-S2 and (1-S2/S1) at Cz, Fz and Pz brain sites (P < 0.05 - 0.01), and no significantly differences with S2-P50 amplitude, S2/S1, S1-S2 and (1-S2/S1) during follow-up (P > 0.05). At baseline, Sch group had a much lowered S1-P50 amplitude than NC group at Cz and Fz brain sites (Cz: Sch: 4.1 microV +/- 2.1 microV, NC: 5.6 microV +/- 3.3 microV, t = -1.47, P = 0.001; Fz: Sch: 3.9 microV +/- 2.1 microV, NC: 5.6 microV +/- 3.9 microV, t = -1.63, P = 0.003). At Month 3, Sch group showed an improved S1-P50 amplitude to normal level at Cz brain site, but S1-P50 amplitude improved at Fz brain site but it was lower than NC group (Sch: 3.9 microV +/- 1.9 microV, NC: 5.6 microV +/- 3.9 microV, t = -1.62, P = 0.03). (3) At Month 3, Sch group showed a much lowered PANSS scale, positive symptom scale, negative symptom scale and general psychiatric symptoms scale than that at baseline (baseline: 138 +/- 15, 33 +/- 7, 41 +/- 5, 65 +/- 8; Month 3: 80 +/- 15, 17 +/- 4, 24 +/- 4, 38 +/- 9 respectively, P < 0.01). Spearman correlation revealed that P50 was not correlated with PANSS at baseline (P > 0.05). After treatment S2/S1 and (1-S2/S1) correlated with positive symptom scale and thought disorder and S1-S2 positively with thought disorder in schizophrenia (P < 0.05). CONCLUSION: Sensory gating deficit is closely related with thought disorder in naïve schizophrenia. And it may be an important pathogenesis of naïve schizophrenia. P50 sensory gating deficit is probably a diathesis marker in schizophrenia.

[Association between depression and G72 gene polymorphism].

OBJECTIVE: To investigate the association between G72 gene polymorphisms and depression,and to probe the difference of G72 gene polymorphisms between depression with and without mixed family history. METHODS: The polymorphisms of G72 gene (rs947267 and rs2181953) were detected by PCR technique in 100 depressive patients without mixed family history, 50 depressive patients with mixed family history and 86 normal controls. RESULTS: (1) The frequencies of rs947267 genotypes and alleles in female depressive patients without mixed family history were significant different to the controls (P=0.017 and P=0.008), the OR scores were 0.300 (A/A, P=0.010), 0.456(A, P=0.008) and 2.195(C, P=0.008) respectively; but in male patients there were no significant differences to the controls (P>0.05). (2) The frequencies of rs2181953 genotypes and alleles in the depressive patients without mixed family history were not significantly different to the controls regardless of sex (P>0.05). (3) The frequencies of rs947267 and rs2181953 genotypes and alleles in the depressive patients with mixed family history were not significantly different to the controls regardless of sex (P>0.05). CONCLUSION: The G72 gene polymorphism may be associated with female depressive patients without mixed family history,C allele of rs947267 may be the risk factor.