Zn concentration in rice grain among three cultivars.

<p>(A) Zn concentration in brown rice. (B) Zn concentration in polished rice. Error bars indicate standard errors of the means (n = 4). Different letters indicate significant difference among Zn treatments according to LSD test (P<0.05).</p

The amount of bioavailable Zn in the polished rice among three cultivars.

<p>Error bars indicate standard errors of the means (n = 4). Different letters indicate significant difference among Zn treatments according to LSD test (P<0.05).</p

Effect of different forms of foliar Zn fertilization on Zn concentration in rice grain.

<p>(A) Zn concentration in brown rice. (B) Zn concentration in polished rice. Error bars indicate standard errors of the means (n = 4). Different letters indicate significant difference among Zn treatments according to LSD test (P<0.05).</p

Effect of different forms of foliar Zn fertilization on the grain protein, phytic acid, Fe and Ca contents of three rice cultivars.

a<p>Different letters after number in the same column designated significant difference by LSD_P<0.05.</p>b<p>Significant effects: NS  =  not significant at P>0.05;</p>*<p>at P<0.05;</p>**<p>at P<0.01;</p>***<p>at P<0.001.</p

Effect of different forms of foliar Zn fertilization on the percentages of solubility, retention, transported and uptake efficiency of Zn among three rice cultivars.

a<p>Different letters after number in the same column designated significant difference by LSD_P<0.05.</p>b<p>Significant effects: NS  =  not significant at P>0.05;</p>*<p>at P<0.05;</p>**<p>at P<0.01;</p>***<p>at P<0.001.</p

Selected physical and chemical properties of the soils.

<p>Selected physical and chemical properties of the soils.</p

Transcriptomic Analysis of Cadmium Stress Response in the Heavy Metal Hyperaccumulator <i>Sedum alfredii</i> Hance

<div><p>The <i>Sedum alfredii</i> Hance hyperaccumulating ecotype (HE) has the ability to hyperaccumulate cadmium (Cd), as well as zinc (Zn) and lead (Pb) in above-ground tissues. Although many physiological studies have been conducted with these plants, the molecular mechanisms underlying their hyper-tolerance to heavy metals are largely unknown. Here we report on the generation of 9.4 gigabases of adaptor-trimmed raw sequences and the assembly of 57,162 transcript contigs in <i>S. alfredii</i> Hance (HE) shoots by the combination of Roche 454 and Illumina/Solexa deep sequencing technologies. We also have functionally annotated the transcriptome and analyzed the transcriptome changes upon Cd hyperaccumulation in <i>S. alfredii</i> Hance (HE) shoots. There are 110 contigs and 123 contigs that were up-regulated (Fold Change ≧2.0) and down-regulated (Fold Change ≦0.5) by chronic Cd treatment in <i>S. alfredii</i> Hance (HE) at q-value cutoff of 0.005, respectively. Quantitative RT-PCR was employed to compare gene expression patterns between <i>S. alfredii</i> Hance (HE) and non-hyperaccumulating ecotype (NHE). Our results demonstrated that several genes involved in cell wall modification, metal translocation and remobilization were more induced or constitutively expressed at higher levels in HE shoots than that in NHE shoots in response to Cd exposure. Together, our study provides large-scale expressed sequence information and genome-wide transcriptome profiling of Cd responses in <i>S. alfredii</i> Hance (HE) shoots.</p></div

Shoot and root biomass of <i>S. alfredii</i> affected by zinc and <i>SaMR12</i> treatment.

<p>Bars plot mean ± SD of three replicate experiments. The different letters above the bars indicate significant differences among treatments at the <i>P</i><0.05 level.</p

Nitrate Shaped the Selenate-Reducing Microbial Community in a Hydrogen-Based Biofilm Reactor

To study the effect of nitrate (NO₃^–) on selenate (SeO₄^2–) reduction, we tested a H₂-based biofilm with a range of influent NO₃^– loadings. When SeO₄^2– was the only electron acceptor (stage 1), 40% of the influent SeO₄^2– was reduced to insoluble elemental selenium (Se⁰). SeO₄^2– reduction was dramatically inhibited when NO₃^– was added at a surface loading larger than 1.14 g of N m^–2 day^–1, when H₂ delivery became limiting and only 80% of the input NO₃^– was reduced (stage 2). In stage 3, when NO₃^– was again removed from the influent, SeO₄^2– reduction was re-established and increased to 60% conversion to Se⁰. SeO₄^2– reduction remained stable at 60% in stages 4 and 5, when the NO₃^– surface loading was re-introduced at ≤0.53 g of N m^–2 day^–1, allowing for complete NO₃^– reduction. The selenate-reducing microbial community was significantly reshaped by the high NO₃^– surface loading in stage 2, and it remained stable through stages 3–5. In particular, the abundance of α-Proteobacteria decreased from 30% in stage 1 to less than 10% of total bacteria in stage 2. β-Proteobacteria, which represented about 55% of total bacteria in the biofilm in stage 1, increased to more than 90% of phylotypes in stage 2. Hydrogenophaga, an autotrophic denitrifier, was positively correlated with NO₃^– flux. Thus, introducing a NO₃^– loading high enough to cause H₂ limitation and suppress SeO₄^2– reduction had a long-lasting effect on the microbial community structure, which was confirmed by principal coordinate analysis, although SeO₄^2– reduction remained intact

Zinc concentration in the plant affected by <i>SaMR12</i> and the zinc treatment.

<p>Bars plot mean ± SD of three replicate experiments. Letters show significance as for <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0106826#pone-0106826-g001" target="_blank">Figure 1</a>.</p