Color Rendering Index over 95 Achieved by Using Light Recycling Process Based on Hybrid Remote-Type Red Quantum-Dot Components Applied to Conventional LED Lighting Devices.

Red color conversion materials have often been used in conventional white LEDs (light-emitting diodes) to enhance the insufficient deep-red component and thus improve the color-rendering property. Quantum dots (QDs) are one of the candidates for this due to their flexibility in controlling the emission wavelength, which is attributed to the quantum confinement effect. Two types of remote QD components, i.e., QD films and QD caps, were prepared and applied to conventional white LED illumination to improve the color-rendering properties. Thanks to the red component near 630 nm caused by the QD components, the color rendering indices (CRIs) of both Ra and R9 could be increased to over 95. It was found that both the diffusing nature of the reflector and the light recycling process in the vertical cavity between the bottom reflector and the top optical films play important roles in improving the color conversion efficiency of remote QD components. The present study showed that the proper application of remote QDs combined with a suitable optical cavity can control the correlated color temperature of the illumination over a wide range, thus realizing different color appearances of white LED illumination. In addition, a high CRI of over 95 could be achieved due to the sufficient excitation from fewer QDs, due to the strong optical cavity effect.

Phosphorylation of the zinc finger transcriptional regulator ZAT6 by MPK6 regulates Arabidopsis seed germination under salt and osmotic stress.

C(2)H(2)-type zinc finger proteins (ZFPs) play diverse roles in plant response to abiotic stresses. ZAT6, an Arabidopsis C(2)H(2)-type ZFP, has been reported to regulate root development and nutrient stress responses. However, its roles in regulation of abiotic stress response are incompletely known. Here, we demonstrate that salt or osmotic stress triggers a strong increase in ZAT6 expression in leaves. Transgenic plants overexpressing ZAT6 showed improved seed germination under salt and osmotic stress. Intriguingly, ZAT6 interacts with a stress-responsive mitogen-activated protein kinase MPK6 in vitro and in planta. ZAT6 is phosphorylated by both recombinant and plant endogenous MPK6. Serine 8 and serine 223 in ZAT6 were identified as the sites phosphorylated by MPK6. In contrast to wild-type form of ZAT6, overexpression of phosphorylation mutant form did not display significantly enhanced salt and osmotic stress tolerance. Altogether, our results suggest that phosphorylation by MPK6 is required for the functional role of ZAT6 in seed germination under salt and osmotic stress.