This study was conducted to assess the potentiality of physiological and biochemical characteristics of the tree at urban habitat using the potable chlorophyll meter (SPAD-502). Urbanization has given rise to many problems, especially air pollution caused by automobile is one of the major risk to human and nature. Although air pollutant concentrations are measured numerically, the data could not explain the synergistic or antagonistic effect of pollutants mixture on various ecosystem. Bio-monitoring using the roadside tree can provide comprehensive information about environmental pollution effect on urban ecosystem. An urban forest and a six-lane roadside area were selected as an experimental site. In this study, 5 parameters including total chlorophyll (Chl), carotenoid (Car), ascorbic acid (AsA) content, relative ion leakage, and leaf temperature were investigated. Chl and Car were extracted from the 0.1g of leaf fresh mass and their contents were calculated by the method of Arnon(1949). For measuring AsA, the supernatant was mixed with reaction mixture and absorptions were measured with a spectrophotometer at 525 nm. Electrolyte leakage was measured using electrical conductivity meter and leaf temperature was monitored by thermal imaging infrared camera. Statistical analysis of the data was performed using SPSS 21.0.
Results/Conclusions
The relationships between the SPAD readings and Chl and Car concentration showed high positive association both G. biloba (Chl: r2=0.9225, Car: r2=0.8462) and P. occidentalis (Chl: r2=0.8843, Car: r2=0.8120). However, a negative linear relationship was observed between the SPAD readings and other tree physiological parameters including AsA content, relative ion leakage and leaf temperature. There was strong nagative relationships between the SPAD readings and relative ion leakage both G. biloba (r2=8338) and P. occidentalis (r2=8239). The relationships between the SPAD readings and AsA and leaf temperature also showed negative association both G. biloba (AsA: r2=0.4635, leaf temperature: r2=0.5946) and P. occidentalis (AsA: r2=0.5608, leaf temperature: r2=0.6151). In conclusion, SPAD-502 could be used as a reliable tool to diagnose potentiality of the photosynthetic efficiency and cell membrane damage in both G. biloba and P. occidentalis. Moreover, the SPAD-502 gives indirect measurement of plant activity with non-destructive and convenient manner. Therefore, the potable chlorophyll meter can help to assess the urban ecosystem health condition.