Floral traits influence pollen vectors' choices in higher elevation communities in the Himalaya-Hengduan Mountains.

BACKGROUND: How floral traits and community composition influence plant specialization is poorly understood and the existing evidence is restricted to regions where plant diversity is low. Here, we assessed whether plant specialization varied among four species-rich subalpine/alpine communities on the Yulong Mountain, SW China (elevation from 2725 to 3910 m). We analyzed two factors (floral traits and pollen vector community composition: richness and density) to determine the degree of plant specialization across 101 plant species in all four communities. Floral visitors were collected and pollen load analyses were conducted to identify and define pollen vectors. Plant specialization of each species was described by using both pollen vector diversity (Shannon's diversity index) and plant selectiveness (d' index), which reflected how selective a given species was relative to available pollen vectors. RESULTS: Pollen vector diversity tended to be higher in communities at lower elevations, while plant selectiveness was significantly lower in a community with the highest proportion of unspecialized flowers (open flowers and clusters of flowers in open inflorescences). In particular, we found that plant species with large and unspecialized flowers attracted a greater diversity of pollen vectors and showed higher selectiveness in their use of pollen vectors. Plant species with large floral displays and high flower abundance were more selective in their exploitation of pollen vectors. Moreover, there was a negative relationship between plant selectiveness and pollen vector density. CONCLUSIONS: These findings suggest that flower shape and flower size can increase pollen vector diversity but they also increased plant selectiveness. This indicated that those floral traits that were more attractive to insects increased the diversity of pollen vectors to plants while decreasing overlap among co-blooming plant species for the same pollen vectors. Furthermore, floral traits had a more important impact on the diversity of pollen vectors than the composition of anthophilous insect communities. Plant selectiveness of pollen vectors was strongly influenced by both floral traits and insect community composition. These findings provide a basis for a better understanding of how floral traits and community context shape interactions between flowers and their pollen vectors in species-rich communities.

In vitro and in vivo anti-cancer activity of formononetin on human cervical cancer cell line HeLa.

Worldwide, cervical cancer (CC) is the third most common malignancy in women, and it remains a leading cause of cancer-related death of women. Genomic studies indicate that phosphoinositide 3-kinase (PI3K)/AKT signaling is one of the most frequently deregulated pathways in several human cancers, including CC. This signaling pathway has an important role in cancer cell proliferation, survival, motility, and metabolism, and therefore could be an attractive therapeutic target. In a previous study, we used a sensitive and high-speed homogeneous assay for the detection of kinase activity and for screening of PI3K/AKT signaling inhibitors in a high-throughput screening (HTS) format and then obtain formononetin, as an O-methylated isoflavone existed in a number of plants and herbs like Astragalus membranaceus. We showed that formononetin inhibited the phosphorylation of AKT and induced the apoptosis of CC cell line HeLa in a dose-dependent manner. Furthermore, formononetin suppressed xenograft tumor growth in nude mice. Our results indicated that formononetin may be used as an anti-cancer drug for cervical cancer in the future.