High concentrations of defects are introduced into nanoscale ZnO through non‐equilibrium processes and resultant blue emissions are comprehensively analyzed, focusing on defect origins and broad controls. Some ZnO nanoparticles exhibit very strong blue emissions, the intensity of which first increase and then decrease with annealing. These visible emissions exhibit strong and interesting excitation dependences: 1) the optimal excitation energy for blue emissions is near the bandgap energy, but the effective excitation can obviously be lower, even 420 nm (2.95 eV < Eg = 3.26 eV); in contrast, green emissions can be excited only by energies larger than the bandgap energy; and, 2) there are several fixed emitting wavelengths at 415, 440, 455 and 488 nm in the blue wave band, which exhibit considerable stability in different excitation and annealing conditions. Mechanisms for blue emissions from ZnO are proposed with interstitial‐zinc‐related defect levels as initial states. EPR spectra reveal the predominance of interstitial zinc in as‐prepared samples, and the evolutions of coexisting interstitial zinc and oxygen vacancies with annealing. Furthermore, good controllability of visible emissions is achieved, including the co‐emission of blue and green emissions and peak adjustment from blue to yellow.

A weak acid selective etching strategy was put forward to fabricate oxide-based hollow nanoparticles (HNPs) using core/shell nanostructures of active metal/oxide nanoparticles as sacrificial templates. ZnO-based HNPs, including pure ZnO, Au/ZnO, Pt/ZnO, and Au/Pt/ZnO HNPs with diameter below 50 nm and shell thickness below 6 nm has been first achieved at low temperature. The diameter, thickness, and even sizes of ZnO and noble metal ultrafine crystals of HNPs can be well adjusted by the etching process. Synchronous with the formation of HNPs, the internal metal-semiconductor interfaces can be controllably eliminated (Zn-ZnO) and reconstructed (noble metal-ZnO). Excitingly, such microstructure manipulation has endued them with giant improvements in related performances, including the very strong blue luminescence with enhancement over 3 orders of magnitude for the pure ZnO HNPs and the greatly improved photocatalytic activity for the noble metal/ZnO HNPs. These give them strong potentials in relevant applications, such as blue light emitting devices, environment remediation, drug delivery and release, energy storage and conversion, and sensors. The designed fabrication procedure is simple, feasible, and universal for a series of oxide and noble metal/oxide HNPs with controlled microstructure and improved performances.

To identify the effect of nitrogen (N) nutrition on photosynthetic efficiency and mesophyll conductance of rice seedlings (Oryza sativa L., cv. 'Shanyou 63' hybrid indica China), hydroponic experiments with different concentrations of N were conducted in a greenhouse. Although leaf N concentration on a dry mass basis increased with increasing supply of N, no significant differences in seedling biomass were observed. A higher light-saturated CO(2) assimilation rate (A) with a high concentration of supplied N was associated with a higher carboxylation efficiency (CE), but not a higher apparent quantum yield (alpha). Based on classic photosynthetic models, both the Rubisco content and the ribulose bisphosphate (RuBP) regeneration rate were sufficient for light-saturated photosynthesis in rice seedlings; the estimated chloroplastic CO(2) concentration (C(c)) and mesophyll conductance (g(m)) demonstrated that a low C(c) was the ultimate limiting factor to photosynthetic efficiency with a higher N supply. Due to a greater chloroplast size (i.e. a shorter distance to the plasma membrane) with a higher supply of N, the CO(2) transport resistance in the liquid phase (g(liq)) in high-N leaves was lower than that in low-N leaves, which resulted in higher g(m) and C(c) in high-N leaves. Although CE(A/Ci) was higher with a high supply of N, there were no differences in CE(A/Cc) between plants grown with different concentrations of N, indicating that the carboxylation capacity of Rubisco between plants grown at different N concentrations was constant. The enhanced photosynthetic rate with supply of a high N concentration was attributed to a higher CO(2) concentration in the chloroplasts, related to a higher mesophyll conductance due to an increased chloroplast size.

The food sector related to agriculture and land use is a major nexus of greenhouse gas (GHG) emissions. Previous studies estimated regional and global emissions, or provided spatial details but for sub-sectors using different methodologies. This study takes the next step forward by providing spatially explicit production-and consumption-based GHG emissions worldwide from plant-and animal-based human food in circa 2010 with a model-data integration approach that ensures full consistency between sub-sectors. Global GHG emissions from the production of food is 17,150 ± 1,760 Tg CO 2 eq/yr, to which the production of animal-based, including livestock feed, contributes 58%, the production of plant-based foods contributes 29%, and the remaining 13% of emissions are caused by other utilizations. Emissions from farmland management activities (38%) and land-use change (30%) are major contributors to total emissions. Rice (12%) and beef (27%) are the largest contributing plant-and animal-based commodities. South and Southeast Asia and South America are the largest emitting regions of production-based emissions.

Rubisco activase (RCA) catalyzes the activation of Rubisco in vivo and plays a crucial role in photosynthesis. However, until now, little was known about the molecular genetics of RCA in soybean (Glycine max), one of the most important legume crops. Here, we cloned and characterized two genes encoding the longer a-isoform and the shorter b-isoform of soybean RCA (GmRCAa and GmRCAb, respectively). The two corresponding cDNAs are divergent in both the translated and 3# untranslated regions. Analysis of genomic DNA sequences suggested that the corresponding mRNAs are transcripts of two different genes and not the products of a single alternatively splicing pre-mRNA. Two additional possible a-form RCA-encoding genes, GmRCA03 and GmRCA14, and one additional b-form RCA-encoding gene, GmRCA11, were also isolated. To examine the function and modulation of RCA genes in soybean, we determined the expression levels of GmRCAa and GmRCAb, Rubisco initial activity, photosynthetic rate, and seed yield in 184 soybean recombinant inbred lines. Correlation of gene expression levels with three other traits indicates that RCA genes could play an important role in regulating soybean photosynthetic capacity and seed yield. Expression quantitative trait loci mapping revealed four trans-expression quantitative trait loci for GmRCAa and GmRCAb. These results could provide a new approach for the modulation of RCA genes to improve photosynthetic rate and plant growth in soybean and other plants.

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Si nanoparticles are synthesized through the “green” (noncontamination) laser ablation method. The size control can be realized by choosing different liquid media. Through comparison of the samples acquired in different liquid media, it is found that ultrafine and well-dispersed Si nanoparticles can be prepared in pure ethanol. Furthermore, such obtained colloid can be further classified by the centrifugation method to obtain certain sized Si nanoparticles. Liquid media also have an effect on the microstructure of the obtained Si nanoparticles. The influence of laser fluence on the mean size of Si nanoparticles is also investigated. As laser fluence increased, the mean size decreased, which is explained in detail. This investigation is crucial in understanding the role of liquid media in the nanoparticles formation process during laser ablation and also has important potential applications in some areas where certain sized Si nanoparticles are needed.

Composite Pt/ZnO porous nanocages with ultrathin porous ZnO shell layers and ultrafine embedded Pt nanoparticles were facilely fabricated by ultrasonic irradiation-assisted two-step etching of Zn/ZnO core/ shell nanoparticle colloids. The Pt cluster size can be well adjusted by the applied ultrasonic power. These Pt/ZnO nanocages exhibit excellent photocatalytic performance and can be further improved by the control of the embedded noble metal nanoparticles, which can be attributed to the abundant nanoscale Schottky contacts in the Pt-ZnO metal-semiconductor interfaces as well as to the large specific surface area due to the unique porous structure. The selective etching route used here could be of considerable universality for fabrication of a series of noble metal/oxide porous nanostructures as photocatalysts, such as the (Au, Ag, Pt, Pd)/(ZnO, TiO 2 ) system.