Effect of crude oil contamination on biomass and chlorophyll biosynthetic pathway pigments and elements content of Avicennia marina seedling

Mangrove ecosystems of Iran, located in the shores of the Persian Gulf, near one of the busiest oil shipping routes, are exposed to petroleum pollution. To assess the effects of petroleum contamination of sediments on morphophysiological characteristics of mangrove (Avecennia marina) seedlings, a randomized block factorial experiment was conducted with three replicates. Biomass and pigment contents (including chlorophyll a, b, protoporphyrin IX, Mg-protoporphyrin IX, protochlorophyllide and total carotenoids) of leaves were assessed in 4-month old seedlings grown on pots containing 500 g of soil exposed to different amounts of Iranian crude oil (2.5, 5, 7.5 and 10% w/w) under ambient conditions. Results showed that the biomass and leaves pigment contents of treated plants,  especially chlorophyll b were reduced compared to non-treated control plants and the initiation of new leaves ceased. In addition, elemental composition of leaves and roots including Ca, K, Mg and Fe in plants grown on 5% oil-contaminated soil were changed compared to control plants.. Our study indicated negative effect of crude oil contamination on growth, development, photosynthesis and nutrition of mangroves.