Temperature rather than N availability determines root exudation of alpine coniferous forests on the eastern Tibetan Plateau along elevation gradients.

Root exudation fulfills fundamental roles in regulating carbon (C)-nutrient cycling in forest ecosystems, yet the main ecological drivers of root exudation and underlying mechanisms in forests under natural gradients remain poorly understood. Here, we investigated the intraspecific variation of root exudation rates in two alpine coniferous forests (Abies faxoniana Rehder et Wilson and Abies georgei Orr) along two elevation gradients on the eastern Tibetan Plateau. Meanwhile, the fine root traits and associated climate and soil parameters were assessed to examine the effects of elevation-dependent changes in climatic and soil nutrient conditions on root exudation. Results showed that root exudation rates decreased with increasing elevation and were positively correlated with mean air temperature. However, the relationships of root exudation with soil moisture and soil nitrogen availability were not significant. The structural equation model (SEM) further revealed that air temperature affected root exudation both directly and indirectly through the effects on fine root morphology and biomass, implying that the adaption of root C allocation and fine root morphological traits to low temperatures primarily resulted in declined root exudation at higher elevations. These results highlight the perceived importance of temperature in determining the elevational variation of root exudation in alpine coniferous forests, which has foreseeably great implications for the exudate-mediated ecosystem C and nutrient processes in the face of drastic warming on the eastern Tibetan Plateau.

Thiophanate-methyl resistance in Sclerotinia homoeocarpa from golf courses in China.

Sclerotinia homoeocarpa causes dollar spot disease on many turfgrass species and is a significant problem worldwide. Thiophanate-methyl (TM), a methyl benzimidazole carbamate (MBC) fungicide, has been used for over forty years to manage dollar spot. Here we describe genetic mutations linked to three distinct TM fungicide resistance phenotypes: sensitive (S), moderately resistant (MR) and highly resistant (HR). These were established using multiple doses of TM, compared to previous studies using single discriminatory doses. In total, 19 S, 3 MR and 22 HR isolates were detected. Analysis of the ß-tubulin gene revealed the MR isolates had a point mutation from T to A at codon 200 changing phenylalanine (TTC) to tyrosine (TAC). Twenty HR isolates had a mutation at codon 198 changing glutamic acid (GAG) to alanine (GCG) and two HR isolates had a mutation at codon 198 changing glutamic acid (GAG) to lysine (AAG). Allele-specific PCR assays were developed for rapid detection of these mutations in isolates of S. homoeocarpa. In addition, our results suggest a two-dose system for in vitro screening provides useful information for monitoring the development of resistance.

Effects of biochar and nitrogen addition on nutrient and Cd uptake of Cichorium intybus grown in acidic soil.

Biochar is an organic amendment used for soil remediation, there are only a few studies documenting the effects of nitrogen on the role of biochar in contaminated soils. A pot experiment was conducted to investigate the impacts of biochar (0%, 1%, and 2.5%, w/w) and nitrogen (0, 100, and 200 mg N kg-1) on plant growth, nutrient and cadmium (Cd) uptake of Cichorium intybus. N, P, Ca, Mg, and Cd concentrations increased with N level in 0% and 1% biochar treatments. In plants treated with 2.5% biochar, 200 mg N kg-1 addition caused significant reductions of N, P, Ca, Mg, and Cd concentrations in comparison to 100 mg N kg-1 treatments. Nitrogen promoted shoot biomass at all biochar treatments, while biochar had no effect on shoot biomass in 0 and 200 mg N kg-1 addition treatments. Nitrogen also significantly increased N, P, K, Ca, Mg, and Cd contents in the 0% and 1.5% biochar addition treatments. Although soil DTPA-extractable Cd concentration showed the lowest values in 1% biochar in combination with 100 and 200 mg N kg-1 addition treatments, lowest shoot Cd concentration, and relatively high shoot biomass occurred in the 2.5% biochar + 200 mg N kg-1 treatment. Based on these results, biochar application at its highest rate (2.5%) in combination with high N supply (200 mg N kg-1) contributed to both crop yield and agricultural product safety. N input alone might increase the risk of human health, and the optimum N dose should be determined during phytostabilization process.

Effects of different fertilizers on growth and nutrient uptake of Lolium multiflorum grown in Cd-contaminated soils.

This study aimed to explore the effects of different fertilizers and their combinations on growth and nutrient and Cd uptake of Lolium multiflorum. Compared with control treatment, chemical fertilizer, organic manure, and their conjunctions with biofertilizer increased shoot biomass. Biofertilizers were found to cause significant reductions in shoot biomass of plants grown in organic manure-treated and control soil. Decreased soil-available N and P and shoot N and K concentrations in biofertilizer amendment treatments indicated that plant growth and nutrient absorption might be negatively affected under nutrient deficiency conditions. Elevated shoot biomasses contributed to the highest shoot Cd contents in chemical fertilizer and chemical fertilizer + biofertilizer treatments among all treatments. But the maximum translocation efficiency occurred in biofertilizer + chemical fertilizer + organic manure treatment, followed by organic manure and chemical fertilizer + organic manure treatments. Based on the results, we can conclude that the application of only the biofertilizer Bacillus subtilis should be avoided in nutrient-limited soils. Chemical fertilizer application could benefit the amount of Cd in shoots, and organic manure application and its combinations could result in the higher translocation efficiency.

The pretreatment thrombocytosis may predict prognosis of patients with colorectal cancer: a systematic review and meta-analysis.

AIM: Recently, several studies have reported that thrombocytosis may be associated with the poor prognosis of colorectal cancer (CRC). Nevertheless, their conclusions were still controversial. Results & methodology: We searched PubMed, Embase, Cochrane Library and Web of Science up to April 2016. A total of 30 studies including 9129 patients were included in this meta-analysis. Thrombocytosis had a close relationship with the poor overall survival of CRC compared with normal platelet counts, with the pooled hazard ratios being 1.89 (95% CI: 1.45-2.47; p < 0.00001) and 1.83 (95% CI: 1.33-2.53; p = 0.0002), with univariate and multivariate analyses, respectively. DISCUSSION & CONCLUSION: This meta-analysis indicated that thrombocytosis may be a cost-effective and noninvasive indicator for poor prognosis of patients with CRC, especially for overall survival.

The prognostic role of pretreatment platelet-to-lymphocyte ratio as predictors in patients with colorectal cancer: a meta-analysis.

AIM: This meta-analysis was designed to analyze and evaluate the prognostic role of preoperative or pretreatment platelet-to-lymphocyte ratio (PLR) in patients with colorectal cancer (CRC). METHOD: We searched PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, Chinese Biomedical Literature Database and WanFang Database up to April 2016. RESULTS: A total of 16 studies (n = 5068 participants) were included for this meta-analysis. Elevated PLR has a close relationship with the poor overall survival of CRC, with the pooled hazard ratio being 1.88 (95% CI: 1.50, 2.36; p < 0.00001). CONCLUSION: This meta-analysis indicated that pretreatment PLR may be a cost-effective and noninvasive serum biomarker for poor prognosis for patients with CRC.

Fourier transform infrared investigation on the state of water in reverse micelles of quaternary ammonium gemini surfactants C12-s-C(12).2Br in n-heptane.

The state of water in the reverse micelles of C12-s-C(12).2Br homologues has been investigated by Fourier transform infrared spectroscopy. The results showed that the solubilized water had four states: the quaternary ammonium head-group-bound, the Br--bound, the bulklike, and the free water. With increasing W0, the number of bulklike water per surfactant (nb) rapidly increased, which indicated swelling of the reverse micelle. The number of the head-bound water per surfactant (nN+) gradually increased. This was attributed to a reduction of the interfacial curvature, which permitted more water molecules to associate with the ionic heads of surfactants and also led to a part of n-hexanol being expelled from the interface and thus water filled up. Owing to the existence of n-hexanol in the interface, the head-bound water of the present system was smaller than that of AOT system at the same W0. The number of counterion-bound water per surfactant (nBr-) remained unchanged with W0. This was due to much smaller dissociation of the head of C12-2-C(12).2Br than that of AOT. With increasing s, unchanged nN+ is attributed to the comprehensive effects of enlarged head, which promotes the hydration, increased ionization degree, and reduced size of the water pool. Owing to increased ionization degree, nBr- increases with s.