RESUMO
Lagerstroemiastenophylla, a new species from southeastern Shaanxi Province and northwestern Hubei Province of China is described. Morphologically, L.stenophylla resembles L.subcostata, but it differs in having 4-angular, subalate branchlets, elliptic-lanceolate, or narrowly elliptic leaves, and relatively larger flowers.
RESUMO
Feng Shui woodlands are naturally or artificially formed green areas in southern China. They are precious for maintaining ecosystem balance in modern semiurban environments. However, they are generally small and geographically isolated from each other, and the status of genetic diversity of the plant species within them has been almost neglected. Therefore, we studied the genetic diversity of the endangered Erythrophleum fordii in eight Feng Shui woodlands (a total of 1,061 individuals) in Guangzhou, a large city in southern China, using microsatellites. For comparison, one population with 33 individuals sampled in a nature reserve was also studied. Although our results indicate that significant demographic declines occurred historically in E. fordii, such declines have not resulted in consistent reductions in genetic variation over generations in Feng Shui populations in the recent past, and the levels of genetic variation in these populations were higher than or comparable to the genetic variation of the population in the nature reserve. In addition, our parentage and paternity analyses indicated widespread and potential long-distance pollen flow within one Feng Shui woodland, indicating the presence of an unbroken pollination network, which would at least partially alleviate the genetic erosion due to habitat fragmentation and the unequal gene contributions of E. fordii parents to their progenies when favorable recruitment habitats are absent under most of the parent trees. Overall, our results suggest that E. fordii in Feng Shui woodlands may not be driven to extinction in the near future. Nevertheless, uncontrolled fast urban development with a lack of awareness of Feng Shui woodlands will cause the local extinction of E. fordii, which has already happened in some Feng Shui woodlands.
RESUMO
The water logging has become the environmental problem of major cities with the sharp increase of impermeable urban pavement as the contributing cause. Abroad, the green roof has been widely used as a practical measure to intercept rainwater, yet the capacity of green roof to retain rainwater varies with climate conditions. As the hot and humid climate zone features high temperature, humidity and precipitation, it is meaningful to study the capacity of green roof to retain rainwater under such climatic condition. In this research, 3 plat forms were set up in Guangzhou in rainy and hot summer to test the capability of simple green roof to retain rainwater runoff, and the efficiency of green roof to retain rainwater under local climate conditions was worked out based on the meteorological observation and data measurement during the 13-month test period. The results showed that the simple green roof with a substrate thickness of 30, 50 and 70 mm could retain 27.2%, 30.9% and 32.1% of precipitation and reduce the average peak value by 18.9%, 26.2% and 27.7%, respectively. Given an urban built-up area of 1035.01 km2 in Guangzhou and a roof area percentage of approximately 37.3% and assuming the green roofs with 30 mm-thick substrate were applied within the area, the light, medium and heavy rain could be delayed at 72.8%, 22.6% and 17.4%, respectively. Accordingly, the rainwater retained could reach up to 14317×104 m3. It suggested the great potential of the simple green roof in retaining rainwater. The research could serve as reference for the hot and humid climate zone to alleviate water logging and visualize sponge city construction.