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Key message: Compared with Magnolia biondii, higher anthocyanin content and higher expression level of related structural genes involved in flavonoids biosynthesis were detected in its variety M. biondii var. purpurascens. Magnolia plants are old species and have evolved a variety of flower colors. Color differences occur between Magnolia biondii (MB) and its variety M. biondii var. purpurascens (MBP). MB shows pink at the bottom and white at the top of petals, while MBP shows purple at the bottom and red at the top. To understand the underlying mechanism of color difference between these two Magnolia plants, the petal color phenotypic parameters, the composition and content of flavonoids, and the expression of related structural genes involved in flavonoids biosynthesis were compared and analyzed between MB and MBP. Generally, L* and b* values of MB were higher than those of MBP, and a* and C* values of MB were lower than those of MBP. Four anthocyanins and ten flavonols were identified in both MB and MBP. Total anthocyanin content (TA) in MBP was higher than that in MB at five developmental stages, while total flavonols content (TF) in MBP was higher than that in MB just at the soft bud stage. TA was significantly negatively correlated with L* value, but showed significant positive correlation with a* and C* values. Higher anthocyanin accumulation in MBP was related with high expression of many structural genes, but lower expression level of MbF3'H in MBP from soft bud stage to half blossom stage retards the increase of anthocyanins' accumulation. These results will provide a foundation for revealing the underlying mechanism of color difference between MB and MBP, and understanding flower color evolution in Magnolia plants. [ABSTRACT FROM AUTHOR]

The purpose of this study was to optimize the light delivery method in a prostate photoacoustic imaging system. A three dimensional (3D) optical model of the human prostate was developed, and the optical energy distribution in the prostate was estimated via three-dimensional Monte Carlo simulation. Then, the feasibility of prostate photoacoustic imaging (PAI) using two endoscopic light delivery methods was studied. Photoacoustic pressure generation and the corresponding photoacoustic images had been obtained and the comparisons were made between each other. Also, the results of cylinder diffusing light source with different lengths were compared. After that, phantom experiment was carried out to validate the simulation results. Our results would be significant in the optimizing photoacoustic imaging system for an accurate diagnosis of prostate cancer. [ABSTRACT FROM AUTHOR]