Transformation of Al Species on Carbon Surfaces: Effects of Al Species and Carbon Surface Oxygen Groups

Control of residual Al is critical, owing to its high tendency to accumulate in drinking water distribution systems and its potential risks to human health. Herein, the effects of surface properties of activated carbon (AC) on intercepting different Al species (including monomeric Al and polymeric Al species-Al13) are evaluated. The results showed that Al in the form of monomers was considerably adsorbed by AC; whereas Al in the form of polymeric Al13 was held to a much lower degree by AC, and the effluent Al concentration was even higher than that without AC. By comparing virgin AC and hydrogen thermal treated AC, the surface oxygen functional groups on the AC were proposed to play a critical role in the transformation of Al species. The oxygen functional groups on the AC surface can directly form complexes with monomeric Al, thereby inducing the binding of monomeric Al on the AC surface. However, the AC surface oxygen groups could not bind to polymeric Al13, and the interaction between AC surface oxygen groups and polymeric Al13 partially transforms Al13 into monomeric Al species, which inhibited the self-aggregation of Al13. This study aims to provide new insights into the control of residual Al in water treatment plants to ensure drinking water safety

Salt Stress Effects on Secondary Metabolites of Cotton in Relation to Gene Expression Responsible for Aphid Development

<div><p>Many secondary metabolites have insecticidal efficacy against pests and may be affected by abiotic stress. However, little is known of how plants may respond to such stress as pertains the growth and development of pests. The objective of this study was to determine if and how salt stress on cotton plants affects the population dynamics of aphids. The NaCl treatment (50mM, 100mM, 150mM and 200mM) increased contents of gossypol in cotton by 26.8–51.4%, flavonoids by 22.5–37.6% and tannic by 15.1–24.3% at 7–28 d after salt stress. Compared with non-stressed plants, the population of aphids on 150 and 200 mM NaCl stressed plants was reduced by 46.4 and 65.4% at 7d and by 97.3 and 100% at 14 days after infestation. Reductions in aphid population were possibly attributed to the elevated secondary metabolism under salt stress. A total of 796 clones for aphids transcriptome, 412 clones in the positive- library (TEST) and 384 clones in the reverse-library (Ck), were obtained from subtracted cDNA libraries and sequenced. Gene ontology (GO) functional classification and KEGG pathway analysis showed more genes related to fatty acid and lipid biosynthesis, and fewer genes related to carbohydrate metabolism, amino acid metabolism, energy metabolism and cell motility pathways in TEST than in Ck library, which might be the reason of aphids population reduction. A comparative analysis with qRT-PCR indicated high expression of transcripts <i>CYP6A14</i>, <i>CYP6A13</i>, <i>CYP303A1</i>, NADH dehydrogenase and fatty acid synthase in the TEST group. However, <i>CYP307A1</i> and two ecdysone-induced protein genes were down regulated. The results indicate that genes of aphids related to growth and development can express at a higher level in reaction to the enhanced secondary metabolism in cotton under salinity stress. The expression of <i>CYP307A1</i> was positively correlated with the population dynamics of aphids since it was involved in ecdysone synthesis.</p></div

The effect of different NaCl stress on secondary metabolites of two cotton cultivars at 7 days after infestation (DAI).

<p>(A) Gossypol contents of SCRC28 and K638; (B) Total flavonoids contents of SCRC28 and K638; (C) The Tannin contents of SCRC28and K638. For each treatment, error bars represent standard deviation. Bars bearing different letters are significantly different at <i>P</i><0.05.</p

KEGG pathway annotation of differentially expressed genes obtained from the subtracted cDNA library.

<p>KEGG pathway annotation of differentially expressed genes obtained from the subtracted cDNA library.</p

Population dynamics of aphids on the cotton cultivars, SCRC28 and K638 under NaCl stress.

<p>Observation was started from aphid infestation. Error bars represent ±SD. Bars bearing different letters are significantly different at <i>P</i><0.05.</p

Sequence of primers used in qRT-PCR.

<p>Sequence of primers used in qRT-PCR.</p

Histogram of Gene Ontology classification from the subtracted cDNA libraries.

<p>The results are summarized in three main categories: biological process, cellular component and molecular function.</p

Effect of Emamectin Benzoate on Root-Knot Nematodes and Tomato Yield

<div><p>Southern root-knot nematode (<i>Meloidogyne incognita</i>) is an obligate, sedentary endoparasite of more than 3000 plant species, that causes heavy economic losses and limit the development of protected agriculture of China. As a biological pesticide, emamectin benzoate has effectively prevented lepidopteran pests; however, its efficacy to control <i>M</i>. <i>incognita</i> remains unknown. The purpose of the present study was to test soil application of emamectin benzoate for management of <i>M</i>. <i>incognita</i> in laboratory, greenhouse and field trials. Laboratory results showed that emamectin benzoate exhibited high toxicity to <i>M</i>. <i>incognita</i>, with LC₅₀ and LC₉₀ values 3.59 and 18.20 mg L^-1, respectively. In greenhouse tests, emamectin benzoate soil application offered good efficacy against <i>M</i>. <i>incognita</i> while maintaining excellent plant growth. In field trials, emamectin benzoate provided control efficacy against <i>M</i>. <i>incognita</i> and resulted in increased tomato yields. Compared with the untreated control, there was a 36.5% to 81.3% yield increase obtained from all treatments and the highest yield was received from the highest rate of emamectin benzoate. The results confirmed that emamectin benzoate has enormous potential for the control of <i>M</i>. <i>incognita</i> in tomato production in China.</p></div

Nematode mortality (%) and lethal concentrations (LC₅₀ and LC₉₀) (mg L^-1) of emamectin benzoate and cadusafos against <i>Meloidogyne incognita</i> (Kofoid and White, 1919) Chitwood, 1949 juveniles (J2, after 48h).

<p>Nematode mortality (%) and lethal concentrations (LC₅₀ and LC₉₀) (mg L^-1) of emamectin benzoate and cadusafos against <i>Meloidogyne incognita</i> (Kofoid and White, 1919) Chitwood, 1949 juveniles (J2, after 48h).</p

Effect of emamectin benzoate and cadusafos on plant height, nematodes control and tomato marketable yields in two field trials.

<p>^<i>a</i> Plant height was determined from 10 plants per plot at 30 and 50 days after transplanting (DAT) in the two field trials.</p><p>^<i>b</i> Nematodes (<i>Meloidogyne incognita</i> (Kofoid and White, 1919) Chitwood, 1949) in 100 cm³ soil were counted at 20, 40 and 60 DAT using a standard sieving and centrifugation procedure in both growing seasons.</p><p>^<i>c</i> Nematode root galling index determined at 14 WAT obtained using a 0–10 scale where 0 = no galls and 10 = 100% of roots galled.</p><p>^<i>d</i> Data are arithmetic means of ten replications and means separated with Student-Newman-Keuls test (<i>P</i> < 0.05). Numbers in the same column followed by the same letter are not significantly different according to Student-Newman-Keuls test (<i>P</i> < 0.05).</p><p>Effect of emamectin benzoate and cadusafos on plant height, nematodes control and tomato marketable yields in two field trials.</p