The effects of petroleum-contaminated soil on photosynthesis of Amorpha fruticosa seedlings

A pot experiment was conducted to monitor the dynamic response of photosynthesis of Amorpha fruticosa seedlings to different concentrations of petroleum-contaminated soils from April to September. The results showed that the photosynthetic rates, stomatal conductance and transpiration rate of seedlings significantly decreased in 5-20 g kg(-1) petroleum-contaminated soil during the three given sampling period of July 31 (early), August 30 (mid-term) and September 29 (late). However, the intercellular CO2 concentration significantly increased in 10 g kg(-1) contaminated soil, while declined in 20 g kg(-1) contaminated soil during the early sampling period as well as in 20 g kg(-1) contaminated soil during the late sampling period. The leaf relative water content of seedlings significantly increased in 20 g kg(-1) contaminated soil during the early sampling period, while it dropped dramatically in 15-20 g kg(-1) contaminated soil during the late sampling period. The contents of chlorophyll a, chlorophyll b and the total chlorophyll of seedlings showed a sharp decline during the three sampling periods in contaminated soil. Comprehensively, considering the negative effects of petroleum on the photosynthesis, growth performance and remediation effect on petroleum of A. fruticosa seedlings, this plant was tolerant of petroleum-contaminated soil and was potentially useful for the phytoremediation of petroleum-contaminated sites in northern Shaanxi, China.