RESUMO
The mountainous regions of southwest China are recognized as pivotal centers for the origin and evolution of Osmanthus species. Baoxing Osmanthus (Osmanthus serrulatus Rehder), a rare and endemic species known for its spring blooms, is sparsely distributed within the high altitude evergreen broad-leaved forests surrounding the southwestern Sichuan Basin. However, persistent anthropogenic disturbances and habitat fragmentation have precipitated a significant decline in its natural population size, leading to the erosion of genetic resources. To assess the genetic status of O. serrulatus and formulate effective conservation strategies, we conducted sampling across ten wild populations, totaling 148 individuals in their natural habitats. We employed two cpDNA fragments (matK and trnS-trnG) to elucidate the phylogeographic structure and historical population dynamics. The results revealed low species-level genetic diversity, alongside pronounced regional differentiation among populations (FST = 0.812, p < 0.05) and a notable phylogeographic structure (NST = 0.698 > GST = 0.396, p < 0.05). Notably, genetic variation was predominantly observed among populations (81.23%), with no evidence of recent demographic expansion across the O. serrulatus distribution range. Furthermore, divergence dating indicated a timeline of approximately 4.85 Mya, corresponding to the late Miocene to early Pleistocene. This temporal correlation coincided with localized uplift events in the southwestern mountains and heightened Asian monsoons, suggesting pivotal roles for these factors in shaping the current phylogeographic pattern of O. serrulatus. These findings support the effective conservation of O. serrulatus germplasm and offer insights into the impact of Quaternary climate oscillations on companion species within evergreen broad-leaved forests. They also enhance our understanding of the origin and evolution of these forests in the southwestern mountains, aiding biodiversity conservation efforts in the region.
RESUMO
Scalable and roll-to-roll compatible processing methods have become pressing needs to transfer organic solar cells (OSCs) to realistic energy sources. Herein a new fabrication method of flexible microcomb printing is proposed. The microcomb is based on a PET sheet micromachined into comb teeth by a laser marker. A computational fluid mechanics simulation shows that the fluid flow around the microcomb teeth induces high shear as well as extensional strain rates, which enhance the molecular alignment and lateral mass transport. The PTQ10:Y6-BO OSCs printed by the flexible microcomb demonstrate a substantially increased degree of crystallinity and phase separation with a suitable domain size. Devices printed by the flexible microcomb in air achieve PCEs of up to 15.93%, higher than those of control devices spin-coated in the N2 glovebox. The flexibility of the PET film makes the microcomb teeth contact directly with the substrate without a suspended liquid meniscus, thus facilitating printing on soft or curved substrates. Printing of flexible OSCs and large-area devices are demonstrated. The flexible OSCs exhibit PCEs of up to 13.62%, which is the highest for flexible OSCs made by scalable printing techniques to date. These results make flexible microcomb printing a feasible and promising strategy toward the manufacture of efficient OSCs.
