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A nutrient solution culture experiment was conducted in the greenhouse to investigate the effects of selenium (Se) on biomass and the mineral nutrient efficiency of macroelements phosphorus, potassium, calcium and magnesium (P, K, Ca and Mg) and microelements iron, manganese, copper and zinc (Fe, Mn, Cu and Zn) in wheat at the seedling stage using a set of recombinant inbred lines (RILs). Quantitative trait locus (QTL) analysis was also performed for all 60 traits. The results showed that 0.1 μmol/L Se can significantly affect the phenotypic traits relation to biomass and nutrient efficiency and the corresponding QTLs. A total of 260 QTLs were located on 19 chromosomes, and 96.54% of these QTLs were only detected in one treatment. A total of 23 important QTL clusters and 31 cooperative uptake and utilization (CUU) loci that colocalized with QTLs for nutrient uptake and/or utilization of at least two elements were also identified. These CUU loci involved 190 out of the 248 QTLs (76.66%) for nutrient efficiency traits, indicating that CUU-QTLs were common for macroelements (P, K, Ca and Mg) and microelements (Fe, Mn, Cu and Zn). Additionally, these loci may be hot spots for genetic control of mineral nutrient efficiency traits. [ABSTRACT FROM AUTHOR]

Objective To evaluate the effects of ultrasonic scaling and compound iodophenol on molar furcation disease. Methods One hundred molars with Class II furcation diseases were treated with uhrasonic scaling or uhrasonic scaling combined compound iodophenol. Bleeding on probing, probing depth and attachment level were assessed before and 1 months after the treatments. Results There was statistically significant difference before and after operation between experiment group and control group. However, in class D furcation disease, uhrasonic scaling combined compound iodophenol showed statistically significant better effects as compared with uhrasonic scaling. Conclusion Uhrasonic scaling combined with compound iodophenol may serve as a nonsurgieal periodontal therapy for Class II molar furcations disease. [ABSTRACT FROM AUTHOR]

Objective The aim was to explore whether the cervical muscle imbalance affect the growth and development of condyle or not. Methods Eighteen 4-week-old male rats were randomly divided into three groups: the experimental group (surgically induced unilateral sternocleidomastoid removal), the contralateral sides group, and the blank control group (nooperation). The rats were killed at intervals up to 5 weeks after surgery, then the morphological changes of condyle were observed by histological observation, and the proliferation and apoptosis of cartilage cells were observed using immunohistochemistry and TUNEL. Results There were significant differences in PCNA positive cell count among three groups in three weeks after operation. However, there was no significant difference in apoptotic cell count among groups. Conclusion Cervical muscle imbalance had effects on condylar cartilage cell proliferation in some degree, while no effects on the growth of condyle. [ABSTRACT FROM AUTHOR]

Microbial residues are an important component of soil organic carbon (SOC). It is unclear how long-term thinning affects the accumulation characteristics of microbial residue carbon (C). We analyzed the differences in soil physicochemical properties, microbial communities, extracellular enzyme activities, and microbial residue C in topsoil (0-10 cm) and subsoil (20-30 cm) in Picea asperata plantation of non-thinned (control, 4950 trees·hm -2 ) and thinned for 14 years (1160 trees·hm -2 ) stands, aiming to reveal the regulatory mechanism of thinning on microbial residue C accumulation. The results showed that thinning significantly increased SOC content, total nitrogen content, available phosphorus content, the proportion of particulate organic C, soil water content, C-cycle hydrolase, and acid phosphatase activities, but significantly reduced the proportion of mineral-associated organic C. Thinning significantly affected the content of fungal and microbial residue C, and the contribution of microbial residue C to SOC, and these effects were independent of soil layer. The content of fungal and microbial residue C was 25.0% and 24.5% higher under thinning treatments. However, thinning significantly decreased the contribution of microbial residue C to SOC by 12.3%, indicating an increase in the proportion of plant-derived C in SOC. Stepwise regression analysis showed that total nitrogen and soil water content were key factors influencing fungal and micro-bial residue C accumulation. In summary, thinning promoted microbial residue C sequestration by altering soil pro-perties and changed the composition of SOC sources.

Stand age is a key factor affecting carbon stocks and fluxes of forest ecosystem. Quantification of the changes in forest productivity with stand development is critically important for optimizing forest age structure, facilitating maximum utilization of resources, and better realizing the role of forests in regulating the uptake, storage, and emission of CO 2 . In this study, using space for time substitution approach, we established 12 chronosequence plots in the broadleaf-Korean pine forests of Lushuihe. Using a locally parameterized Biome-BGC model, we simulated the dynamics of net primary productivity (NPP) with stand development and examined the changes with stand development in NPP of broadleaf-Korean pine forests under four developmental scenarios. Results showed that the biomass in broadleaf-Korean pine forests of different age-classes ranked in the order of young stand < mid-age stand < mature stand < over-mature stand, with the average value of (224.35±20.68), (237.23±39.96), (259.16±19.51), and (357.57±84.74) t·hm -2 , respectively. Modelled NPP in broadleaf-Korean pine forests of different developmental stages varied in the range of 489.8-588 g C·m -2 ·a -1 , which were consistent with the observed data of MODIS NPP, highlighting the adequacy and accuracy of Biome-BGC model in simulating the carbon flux of broadleaf-Korean pine forests. Simulated NPP displayed a pattern of initial increase and later decrease with stand development, reaching peak in the mid-age stand and being smallest in the over-mature stand. Simulations of NPP in broadleaf-Korean pine forest under four developmental scenarios showed that, for the two scenarios with planted Korean pine forests experiencing either natural development or controlled cutting, NPP was highest in the mature stage; whereas for the two scenarios with initial natural secondary birch forests experiencing either natural development or controlled cutting, NPP was highest in the young stage.

Soil acidification of large areas of paddy fields in southern China has become an important problem in rice production. Therefore, how to ameliorate or remedy the acidifying paddy soil and to exposit its mechanism has important theoretical and practical significance for rebuilding healthy soils and guaranteeing national food security. Although lime has already been extensively used to remedy acidified soils, long-term application of a large amount of lime would not only cause the soil to harden, but also disturb the balance between calcium, potassium and magnesium in the soil. Given the advantages of lower solubility and comprehensive nutrient supply, fertilizer of calcium silicon magnesium potassium (CSMP) may be used as an alternative. The aim of this study was to clarify the functions of CSMP and its effects on soil acidification in paddy fields. A four-year field experiment was conducted to investigate the dynamics of soil pH, exchangeable acidi-ty, exchangeable base cation and available silicon, as well as 0~30 cm pH buffer capacity (pHBC), net base production under CSMP fertilization in the paddy soil. There were five treatments, i.e. CK (traditional fertilization practice of the local farmers), treatment I (CK plus 750 kg·hm -2 CSMP); treatment II (CK plus 1125 kg·hm -2 CSMP), treatment III (CK plus 1500 kg·hm -2 CSMP), and treatment IV (CK plus 1875 kg·hm -2 CSMP). The results showed that the traditional fertilization practice of the local farmers resulted in a decline of soil pH, soil exchangeable base cation and base saturation year by year, but soil exchangeable acid was increased with year. Conversely, CSPM fertlization significantly raised soil pH, with the magnitude of increases positively depending on the number of application times or application rate. Continuous and repeated application of CSMP effectively promoted the accumulation of exchangeable base cation and the consumption of soil exchangeable acid in paddy soil, especially for the accumulation of soil exchangeable Ca 2+ , Mg 2+ and the consumption of soil exchangeable Al 3+ . Furthermore, the more amount of CSPM application resulted in the more accumulation or consumption, but with relatively slower rate. The exchangeable base cation and alkali released by CSMP contributed 108.8% to the total reduction of soil exchangeable acid, suggesting that it was the main path to reduce soil exchangeable acid. Meanwhile, CSMP application improved soil acidity in paddy field, with the content of available silicon increased year by year and the increase amplitude became larger with the more amount of CSMP application. The traditional fertilization of local farmers resulted in soil acidification, with a acidification rate was 2.86 kmol H + ·hm -2 ·a -1 . CSMP application could effectively control soil acidification, producing a lot of alkalinity with net alkalinity production of 9.93-13.82 kmol OH - ·hm -2 ·a -1 . CSPM could release Ca 2+ , Mg 2+ and alkali, which would mitigate soil acidification in paddy fields.

An atrazine-degrading strain HB-5 was used as a bacteria for biodegradation. Treatments of soil with nitrogen single, phosphate single and nitrogen phosphate together with HB-5 were carried out for degradation and eco-toxicity test; then, relationship between atrazine degradation rate and soil available nitrogen, available phosphorus were discussed. Atrazine residues were determined by HPLC; available nitrogen was determined with alkaline hydrolysis diffusion method; available phosphorus was determined with 0.5 mol/L-NaHCO3 extraction and molybdenum stibium anti-color method, and toxicity test was carried out with micronucleus test of Vicia faba root tip cells. The results showed that: After separately or together application, nitrogenous and phosphorous fertilizers could significantly accelerate atrazine degradation than soil with HB-5 only. On day 5, the order of atrazine degradation was ANP > AP > AN > A; 7 days later, no statistically significant differences were found between treatments. The available nitrogen and phosphorus level in soil reduced as the degradation rate increased in the soil. The soil of eco-toxicity test results indicated that the eco-toxicity significantly reduced with the degradation of atrazine by HB-5, and the eco-toxicity on treatments of soil with fertilizer were all below the treatments without fertilizer. On day 5, the order of eco-toxicity was ANP < AP < AN < A; 7 days later, all treatments were decreased in control levels. So, adjusting soil nutrient content could not only promote atrazine degradation in soil but also could reduce the soil eco-toxicity effects that atrazine caused. All these results could be keystone of atrazine pollution remediation in contaminated soil in the future.