Scenarios of genes to metabolites in Artemisia annua remain uninvestigated. Here, we report the use of an integrated approach combining metabolomics, transcriptomics, and gene function analyses to ...charac- terize gene-to-terpene and terpene pathway scenarios in a self-pollinating variety of this species. Eightyeight metabolites including 22 sesquiterpenes （e.g., artemisinin）, 26 monoterpenes, two triterpenes, one diterpene and 38 other non-polar metabolites were identified from 14 tissues. These metabolites were differentially produced by leaves and flowers at lower to higher positions. Sequences from cDNA libraries of six tissues were assembled into 18 871 contigs and genome-wide gene expression profiles in tissues were strongly associated with developmental stages and spatial specificities. Sequence mining identified 47 genes that mapped to the artemisinin, non-amorphadiene sesquiterpene, monoterpene, triterpene, 2-C- methyl-D-erythritol 4-phosphate and mevalonate pathways. Pearson correlation analysis resulted in network integration that characterized significant correlations of gene-to-gene expression patterns and gene expression-to-metabolite levels in six tissues simultaneously. More importantly, manipulations of amorpha-4,11-diene synthase gene expression not only affected the activity of this pathway toward artemisinin, artemisinic acid, and arteannuin b but also altered non-amorphadiene sesquiterpene and genome-wide volatile profiles. Such gene-to-terpene landscapes associated with different tissues are fundamental to the metabolic engineering of artemisinin.
Grafting is a widely used practice in fruit-bearing vegetables. However, why grafting affects plant growth, fruit yield, and quality, especially from the aspect of mineral nutrition, remains unclear. ...In this study, watermelon cultivar ‘Zaojia 8424’ was grafted onto bottle gourd ‘Jingxinzhen1’（Lagenaria siceraria） and pumpkin ‘Qingyanzhen 1’（Cucurbita maxima × C. moschata）. Non-grafted plants were used as the control. Results show that rootstock grafting significantly increases plant growth and single fruit weight of watermelon. Watermelon grafted onto rootstocks, especially pumpkin, exhibits significantly higher root volume, root surface area, and number of root tips and forks in comparison with non-grafted plants. Fruit flesh, rind firmness, and rind thickness were enhanced by grafting. However, fruit soluble solids and taste significantly decreased in plants grafted onto pumpkin. The total uptake(mg · plant-1) and concentration(mg · g-1DW) of N, K, Ca, Fe, Mg, and Mn in root, stem, leaf,fruit rind, and flesh were generally higher in grafted plants compared to non-grafted ones, especially for N of pumpkin rootstock-grafted plants.The total uptake of nutrients of plants grafted onto bottle gourd and pumpkin was increased by 30.41% and 49.14% at fruit development stage and by 21.33% and 47.46% at fruit maturation stage, respectively, compared with non-grafted plants. We concluded that watermelon grafting onto suitable rootstocks can increase the uptake of mineral nutrition, especially for N in the pumpkin rootstock grafted plants, thereby affecting plant growth, fruit yield, and quality.
An experimental study of condensation nuclei formation for the system of SO$\sb2$-O$\sb3$-NO$\sb2$-water vapor-zero grade air at one atmosphere and room temperature has been conducted. In the ...experiments, nitrogen dioxide and ozone were mixed to generate NO$\sb3$ and N$\sb2$O$\sb5$; the O$\sb3$/NO$\sb2$/NO$\sb3$/N$\sb2$O$\sb5$ mixture and sulfur dioxide and water vapor were introduced into a specially designed sheath flow reaction vessel in which the oxidation of sulfur dioxide by NO$\sb3$ and N$\sb2$O$\sb5$ occurred to produce condensation nuclei which were quantitatively determined. The results of several series of experiments accomplished at different concentrations of each of the reactants are presented. The correlations of observed concentrations of condensation nuclei to concentrations of sulfur dioxide, nitrogen dioxide, ozone and water vapor are evaluated. A model of the mechanism of condensation nuclei formation is established in terms of the following chemical reaction sequence:(UNFORMATTED TABLE OR EQUATION FOLLOWS)$$\eqalign{\rm NO\sb2&+ \rm O\sb3 \to NO\sb3 + O\sb2\cr\rm NO\sb3&+ \rm NO\sb2 + M \to N\sb2O\sb5 + M\cr\rm SO\sb2&+ \rm NO\sb3 \to SO\sb3 + NO\sb2\cr\rm SO\sb2&+ \rm N\sb2O\sb5 \to SO\sb3 + N\sb2O\sb4\ (or\ 2\ NO\sb2)\cr\rm SO\sb3&+ \rm H\sb2O + M \to CN + M\cr}$$(TABLE/EQUATION ENDS) The last reaction accounts in a non-specific manner for the formation of condensation nuclei (CN). From the kinetic analysis of the experimental results, estimates are derived for the rate constants of the following reactions:(UNFORMATTED TABLE OR EQUATION FOLLOWS)$$\eqalign{&\rm SO\sb2 + NO\sb3 \to SO\sb3 + NO\sb2,\ k \le 4.5 \times 10\sp{-21}\ cm\sp3\ molecule\sp{-1} sec.\sp{-1}\cr&\rm SO\sb2 + N\sb2O\sb5 \to SO\sb3 + N\sb2O\sb4,\ k = 9.1 \times 10\sp{-24}\ cm\sp3\ molecule\sp{-1} sec.\sp{-1}\cr}$$(TABLE/EQUATION ENDS)at 26.5$\sp\circ$C, which are below the upper limit values reported previously.
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