RESUMO
Brandisia is a shrubby genus of about eight species distributed basically in East Asian evergreen broadleaved forests (EBLFs), with distribution centers in the karst regions of Yunnan, Guizhou, and Guangxi in southwestern China. Based on the hemiparasitic and more or less liana habits of this genus, we hypothesized that its evolution and distribution were shaped by the development of EBLFs there. To test our hypothesis, the most comprehensive phylogenies of Brandisia hitherto were constructed based on plastome and nuclear loci (nrDNA, PHYA and PHYB); then divergence time and ancestral areas were inferred using the combined nuclear loci dataset. Phylogenetic analyses reconfirmed that Brandisia is a member of Orobanchaceae, with unstable placements caused by nuclear-plastid incongruences. Within Brandisia, three major clades were well supported, corresponding to the three subgenera based on morphology. Brandisia was inferred to have originated in the early Oligocene (32.69 Mya) in the Eastern Himalayas-SW China, followed by diversification in the early Miocene (19.45 Mya) in karst EBLFs. The differentiation dates of Brandisia were consistent with the origin of keystone species of EBLFs in this region (e.g., Fagaceae, Lauraceae, Theaceae, and Magnoliaceae) and the colonization of other characteristic groups (e.g., Gesneriaceae and Mahonia). These findings indicate that the distribution and evolution of Brandisia were facilitated by the rise of the karst EBLFs in East Asia. In addition, the woody and parasitic habits, and pollination characteristics of Brandisia may also be the important factors affecting its speciation and dispersal.
RESUMO
To accurately and quantitatively evaluate the mass and particle size distribution of water-soluble and water-insoluble particulate matters (PM) on the surface of tree leaves, which would help to improve the accuracy of quantitative assessment of the retention ability of urban trees to atmospheric particles, we collected leaf samples from three broadleaved tree species [Ginkgo (Ginkgo biloba), Chinese scholar tree (Sophora japonica) and weeping willow (Salix babylonica)] and two conifer species [Chinese pine (Pinus tabuliformis) and China savin (Sabina chinensis)] 14 d after the rain (rainfall>15 mm). The PMs retained on leaves were collected by a succeeding procedure of washing + brushing (WC+BC) and ultrasonic cleaning (UC). Then, the extracts at each step were divided into water-soluble and water-insoluble PMs through centrifuge. The mass of water-soluble and water-insoluble particles were dry weighted. Then, the water-soluble and water-insoluble particles were dissolved by anhydrous ethanol and deionized water to measure the particle size distribution. The mass of water-soluble and water-insoluble particles with different particle sizes was calculated. Results showed that the mass (proportion) of water-soluble PMs retained on leaf surfaces of broad-leaved and conifer species were 480.61 (52.3%) and 438.91 (47.7%) mg·m-2, respectively, while that for water-insoluble PMs were 97.93 (12.0%) and 715.84 (88.0%) mg·m-2, respectively. The particle size distribution of water-soluble particles on the leaves of the five tree species showed the unimodal curve with mean size of 40.36 µm. Water-insoluble particles on leaves showed multimodal distribution, with mean size of 105.65 µm. S. japonica and G. biloba had higher PM retention ability in regions suffering with more water-soluble PM pollution, while S. chinensis had higher retention ability to water-insoluble PMs.
