A novel, pleiotropic sweet orange (Citrus sinensis L. Osbeck) mutant, 'Hong Anliu', is described. This mutation causes carotenoid accumulation, high sugar, and low acid in the fruits. Gas chromatographic analysis revealed that high sugar and low acid in the fruit were caused by the accumulation of sucrose and the deficiency of citric acid. The dominant carotenoid accumulated in albedo, segment membranes, and juice sacs is lycopene, which can reach levels that are a 1000-fold higher than those in comparable wild-type fruits. This mutation does not affect the carotenoid composition of leaves. Carotenoid concentration and biosynthetic gene expression of albedo, segment membranes, and juice sacs were dramatically altered by the mutation. Lycopene accumulation in the juice sacs was regulated by co-ordinate expression of carotenoid biosynthetic genes. However, in albedo and segment membranes, the expression of downstream carotenogenic genes seems to be feedback induced by lycopene accumulation. This implies that there must be at least two modes regulating lycopene accumulation in 'Hong Anliu' fruit. Taken together, these results suggest that massive amounts of lycopene might be synthesized in the juice sacs and then transported to the segment membrane and the albedo, which leads to lycopene accumulation there.

Citrus is an important fruit crop as regards accumulation of carotenoids. In plant carotenoid biosynthesis, phytoene synthase gene (Psy) plays a key role in catalyzing the head-to-head condensation of geranylgeranyl diphosphate molecules to produce colorless phytoene. In the present paper, we reported the phytoene contents determination and characterization of Psy during fruit ripening of "Washington" navel orange and its red-fleshed mutant "Cara Cara". Results showed that phytoene was exclusively accumulated in peel and pulp of "Cara Cara". Although phytoene was observed accumulating with fruit ripening of "Cara Cara", the contents in pulp were 10 times higher than those in peel. The isolated two Psy cDNAs were both 1520 bp in full length, containing 436 deduced amino acid residues, with a different amino acid at 412th. Genomic hybridization results showed that one or two copies might be present in "Cara Cara" and "Washington" genomes. During "Cara Cara" and "Washington" fruit coloration, expression of Psy was observed to be up-regulated, as revealed by tissue specific profiles in the flavedo, albedo, segment membrane and juice sacs. However, Psy expression in albedo of "Cara Cara" was higher than that in "Washington", as evidenced by phytoene accumulation in the peel.

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Electric toroidal dipolar response has been achieved by metamaterial based on sun-like aperture element at microwave frequency. It is confirmed numerically by scattered powers that the electric toroidal dipolar moment dominates over other moments at the corresponding resonance. This proposed metamaterial exhibits resonant transparency under linearly polarized incidence caused by destructive interference between magnetic dipole and electric toroidal dipole. Notably, it also provides circular cross-polarization conversions between left-handed circularly polarized wave and right-handed circularly polarized wave at the same frequency. These properties associated with elusive electric toroidal dipolar moment offer an avenue for various potential applications in microwave devices.

In this paper, a broadband metamaterial absorber (MA) based on a multi-layer structure is presented. The advantages of this MA are the small periodic unit size, they are thin, have excellent polarization characteristics and are adaptive for wide angles of oblique incident electromagnetic waves. The unit cell of the broadband MA is composed of three dual-band sub-cells; each presents two resonant frequencies so as to form a wide absorptive spectrum when stacked. The sandwiched dual-band sub-cell is composed of one metallic annular patch and one metallic circular patch each etched on a lossy substrate. The radii of the metallic patches forming each sub-cell are different so as to appear to have different resonant frequencies. In the design of the unit cell there are metallic circular patches and an air layer at the bottom of each sub-cell to form magnetic coupling and avoid coupling between sub-cells. The broadband MA presents good absorptivity above 80% between 8.8 and 10.8 GHz, with a full width at half maximum (FWHM) absorption bandwidth of 2.3 GHz and a relative FWHM absorption bandwidth of 23%.