Pollution Induced Alterations of Cellular Structures and Functions in Leaves of Subtropical Forest plants

Environmental pollution has caused soil, water and air quality to degradate and plant diversity to decline in terrestrial ecosystems. According to previous studies, the response strategy and degree of toxicity to environmental pollutions are different among plant species but the exact toxicity mechanisms in plant cells have not been fully elucidated. Therefore, changes in cellular structures and functions of subtropical forest plants under air pollution (such as SO2) and heavy metals (such as Pb and Cd) were investigated by Dr. LIU Nan and Prof LIN Zhifang in South China Botanical Garden, Chinese Academy of Sciences.

It is revealed that chloroplast of a dominant species, A. acuminatissima, in the late succession stage of a subtropical forest in South China, was less sensitive to SO2 byproduct HSO3-. Conversely, the photosynthetic apparatus of P. massoniana, the pioneer heliophyte species, was susceptible to HSO3-. From the forest development and succession point of view, when this subtropical forest suffers from SO2 pollution, the replacement of understory P. massoniana seedlings by adult A. acuminatissima tree and other forest plants might be accelerated.

Alocasia macrorrhiza is a fast growing and propagating herbaceous species commonly found in subtropical forests. After treated by different concentrations of Pb2+ and Cd2+, the formation of reactive oxygen in plant tissue was found to be exaggerated. Under higher concentration of Pb2+, plant leaves still held a fairly cell viability and photosystem II functions. It is deduced that A. macrorrhiza could be a Pb tolerant species.

Contrasting researches can help us to understand the differences of forest plant sensitivities to environmental pollutions and to predict the potential effects of soil, water and air pollution on forest structure and understory plant diversity. These scientific findings have been published on environmental science journals, Ecotoxicology, and Ecotoxicology and Environmental Safety.