The effect of arbuscular mycorrhizal fungi and biochar on the growth and Cd/Pb accumulation in Zea mays.

A greenhouse pot experiment was conducted to assess the effects of biochar (BC) and arbuscular mycorrhizal fungus (AMF)-Funneliformis mosseae (Fm), Glomus versiforme (Gv) and Rhizophagus intraradices (Ri) on the plant growth and Cd/Pb accumulation by corn grown in the soils artificially contaminated with 5 mg Cd and 300 mg Pb kg-1 soil. The single AMF inoculation and combined usage of AMF and BC evidently improved the P contents of maize. Furthermore, the combined use of AMF and BC produced pronounced positive effect on corn growth, and the shoot biomass in Gv + BC group was 9.85-fold higher than that of the control. Meanwhile, the single BC addition and combined utilization of AMF and BC significantly reduced Cd and Pb concentrations in maize, and the greater reduces were found in the combined utilization, and the lowest Cd concentration of shoot was appeared in Gv + BC group. The single BC addition and combined application of AMF and BC significantly increased soil pH, and reduced soil diethylenetriaminepentaacetic acid (DTPA)-extractable Cd/Pb. This study demonstrated a synergistic effect between AMF (Gv, Fm, Ri) and BC on improving maize growth and decreasing Cd/Pb accumulation in maize, and the combined use of Gv and BC brought the most pronounced effect, which could provide a feasible strategy for safe production of maize from Cd/Pb-polluted soils.

Combined application of arbuscular mycorrhizal fungi and steel slag improves plant growth and reduces Cd, Pb accumulation in Zea mays.

Little attention has been paid to the combined use of arbuscular mycorrhizal fungus (AMF) and steel slag (SS) for ameliorating heavy metal polluted soils. A greenhouse pot experiment was conducted to study the effects of SS and AMF-Funneliformis mosseae (Fm), Glomus versiforme (Gv) and Rhizophagus intraradices (Ri) on plant growth and Cd, Pb uptake by maize grown in soils added with 5 mg Cd kg-1 and 300 mg Pb kg-1 soil. The combined usage of AMF and SS (AMF + SS) promoted maize growth, and Gv + SS had the most obvious effect. Meanwhile, single SS addition and AMF + SS decreased Cd, Pb concentrations in maize, and the greater reductions were found in combined utilization, and the lowest Cd, Pb concentrations of maize appeared in Gv + SS. Single SS amendment and AMF + SS enhanced soil pH and decreased soil diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Pb concentrations. Furthermore, alone and combined usage of AMF and SS increased contents of soil total glomalin. Our research indicated a synergistic effect between AMF and SS on enhancing plant growth and reducing Cd, Pb accumulation in maize, and Gv + SS exerted the most pronounced effect. This work suggests that AMF inoculation in combination with SS addition may be a potential method for not only phytostabilization of Pb-Cd-contaminated soil but maize safety production.

Arbuscular mycorrhizal fungi alleviate Cd phytotoxicity by altering Cd subcellular distribution and chemical forms in Zea mays.

Arbuscular mycorrhizal fungus (AMF) can relieve Cd phytotoxicity and improve plant growth, but the mechanisms involved in this process have still been not completely known. In the present work, a pot experiment was conducted to examine productions of glutathione (GSH) and phytochelatins (PCs), and absorption, chemical forms and subcellular distribution of Cd in maize (Zea mays) inoculated with or without AMF (Rhizophagus intraradices (Ri) and Glomus versiforme (Gv)) in Cd-amended soils (0, 1 and 5 mg Cd kg-1 soil). In general, both Ri and Gv inoculation dramatically enhanced biomass production and reduced Cd concentrations in shoots and roots of maize when compared to the non-mycorrhizal treatment. Moreover, both Ri and Gv symbiosis obviously increased contents of GSH and PCs, both in shoots and roots. Subcellular distribution of Cd in maize indicated that most of Cd (more than 90%) was accumulated in cell wall and soluble fraction. In addition, Cd proportions in soluble fractions in shoots of maize inoculated with Gv or Ri were considerably increased, but reduced in cell wall fractions compared to non-mycorrhizal maize, indicating that mycorrhizal symbiosis promoted Cd transfer to vacuoles. Furthermore, proportions of Cd in inorganic and water-soluble forms were declined, but elevated in pectates and proteins-integrated forms in mycorrhizal maize, which suggested that Gv and Ri could convert Cd into inactive forms. These observations could provide a further understanding of potential Cd detoxification mechanism in maize inoculated with AMF.

[Clinical analysis of 108 cases with adenocarcinoma Barretts's esophagus].

OBJECTIVE: To investigate the prognostic factors and to analyze the efficacy of chemotherapy and/or radiotherapy for Barrett's esophageal adenocarcinoma after radical surgical resection. METHODS: The clinical data of 108 patients with adenocarcinoma Barrett's esophagus picking out from 783 esophageal adenocarcinoma patients surgically treated between June 1978 to June 2001 in the Shandong Provincial Hospital and Shandong Qianfoshan Hospital were analyzed retrospectively. 60Co gamma-irradiation or 6MVX-ray with conventional fraction were used for radiotherapy with a total volume dosage of 55-70 Gy. The chemotherapy was either FAM (iv infusion of 5-Fu 500 mg, d1-d5; ADM 50 mg d1; MMC 12 mg, d1) or CMF regimen (iv infusion of CTX 800 mg d1, d8; MTX 30 mg d1; 5-Fu 500 mg, d1-d5) for 4-6 cycles. The Kaplan-Meier amalysis was used to estimate the survival rate. Log rank test was used for comparison of the survival difference among different groups. RESULTS: In this series, 76 of 92 patients who underwent radical surgical resection received postoperative radiotherapy alone, and 16 received radiotherapy plus chemotherapy. Twelve of the other 16 patients who underwent palliative surgical resection received chemotherapy plus radiotherapy, the remaining 4 patients died of operative complications during surgery. The overall 1-, 3- and 5-year survival rate of this series was 81.5%, 51.9% and 22.2%, respectively. In the radical resection group, it was 15.8% for the patients received radiotherapy alone versus 75.0% for those treated by chemotherapy plus radiotherapy. The 5-year survival rate was 33.3% for the patients without extra-esophageal infiltration and 33.3% for the patients without lymph node metastasis, respectively. However, it was only 9.1% for the patients with extra-esophageal infiltration and 14.3% for those with lymph node metastasis, respectively. For the patients who had palliative surgical resection, though they received chemotherapy plus radiotherapy postoperatively, none of them survived longer than 5-year. Statistically significant difference among these groups was demonstrated by Log rank test (P < 0.05). CONCLUSION: Chemotherapy plus radiotherapy after radical surgical resection may improve the survival of patients with adenocarcinoma in Barrett's esophagus adenocarcinoma patient. The pathological stage, extra-esophageal infiltration, lymph node metastasis and postoperative chemotherapy plus radiotherapy are important prognostic factors.