12 research outputs found
Analysis of light scattering off photonic crystal slabs in terms of Feshbach resonances
Techniques to deal with Feshbach resonances are applied to describe resonant
light scattering off one dimensional photonic crystal slabs. Accurate
expressions for scattering amplitudes, free of any fitting parameter, are
obtained for isolated as well as overlapping resonances. They relate the
resonance properties to the properties of the optical structure and of the
incident light. For the most common case of a piecewise constant dielectric
function, the calculations can be carried out essentially analytically. After
establishing the accuracy of this approach we demonstrate its potential in the
analysis of the reflection coefficients for the diverse shapes of overlapping,
interacting resonances.Comment: 12 pages, 5 figure
Overexpression of UV-DAMAGED DNA BINDING PROTEIN 1 links plant development and phytonutrient accumulation in high pigment-1 tomato
Fruits of tomato plants carrying the high pigment-1 mutations hp-1 and hp-1w are characterized by an increased number of plastids coupled with enhanced levels of functional metabolites. Unfortunately, hp-1 mutant plants are also typified by light-dependent retardation in seedling and whole-plant growth and development, which limits their cultivation. These mutations were mapped to the gene encoding UV-DAMAGED DNA BINDING PROTEIN 1 (DDB1) and, recently, fruit-specific RNA interference studies have demonstrated an increased number of plastids and enhanced carotenoid accumulation in the transgenic tomato fruits. However, whole-plant overexpression of DDB1, required to substantiate its effects on seedling and plant development and to couple them with fruit phenotypes, has heretofore been unsuccessful. In this study, five transgenic lines constitutively overexpressing normal DDB1 in hp-1 mutant plants were analysed. Eleven-day-old seedlings, representing these lines, displayed up to ∼73- and ∼221-fold overexpression of the gene in hypocotyls and cotyledons, respectively. This overexpression resulted in statistically significant reversion to the non-mutant developmental phenotypes, including more than a full quantitative reversion. This reversion of phenotypes was generally accompanied by correlated responses in chlorophyll accumulation and altered expression of selected light signalling genes: PHYTOCHROME A, CRYPTOCHROME 1, ELONGATED HYPOCOTYL 5, and the gene encoding CHLOROPHYLL A/B-BINDING PROTEIN 4. Cumulatively, these results provide the missing link between DDB1 and its effects on tomato plant development