The effects of urban impervious surfaces on eco-physiological characteristics of Ginkgo biloba: A case study from Beijing, China

Accelerated urbanization continues to convert natural lands to impervious surfaces, resulting in serious impacts to the environment, and affecting the growth of urban plants. In this study, we evaluated eight environmental factors, and nine eco-physiological characteristics of Ginkgo biloba planted on two types of impervious surface (totally impervious surface and partly impervious surface), and one non-impervious surface (grass land). Results showed that the primary effect of the impervious surfaces on the environment were increasing air temperature (Ta) and soil temperature (Ts), and decreasing relative humidity of air (RH) and soil moisture content (SMC). G. biloba net photosynthetic rate (Pn) on totally impervious surfaces (TIS), and partly impervious surfaces (PIS) was 39% and 22% lower than trees on an urban grass land (GL). Tr and Gs also showed similar reductions. Compared to GL, FV/Fm on TIS and PIS decreased 7% and 6%, respectively, and ΦPSII decreased 32% and 41%, respectively. Water use efficiency (WUE), light use efficiency (LUE), and CO2 use efficiency (CUE) of G. biloba growing on impervious surfaces were 20-40% less than those on the grass land. Redundancy analysis (RDA) indicated the combination of environmental factors explained 66% of the variation of G. biloba eco-physiological responses. This study revealed the eco-physiological responses and variation of G. biloba to different substrates. Results indicated it is vital to improve plant environmental quality, and enhance urban green ecological services. Our study provides a scientific reference for urban greening, and ecological land construction.