Lead transformation in arbuscular mycorrhizal assistant constructed wetlands

Meijun Chen

Master's thesis

Abstract:

Heavy metal pollution in water has gained many focuses in recent years. But arbuscular mycorrhizal fungi (AMF) assist plants to remove heavy metals from water in constructed wetlands (CWs) has been rarely studied, and the heavy metal transformation in wetlands with AMF has been poorly reported. This study investigated how lead (Pb) transformed in wetlands with the assistance of AMF. Eighteen pots experiment were settled at the campus of the Czech University of Life Science (CULS). Iris wilsonii were planted in pots in May 2019. Plant samples were collected in November. The results showed AMF colonization decreased by 7.11%–50.9% under Pb stress, but still sufficient enough to be functional for plants. AMF significantly increased plant growth, with root length, shoot height, root weight, shoot weight, phosphorus concentration, and potassium concentration increased by 19%–39%, 3%–16%, 44%–67%, 20%–86%, 11%–23%, and 11%–19%, respectively. AMF increased photosynthesis properties of plants such as photochemical efficiency and leaf chlorophyll contents, by 4%–65% and by 6%–39% under Pb stress respectively. The enzyme activities of POD, SOD and soluble protein contents were enhanced by 0.5%–457%, 27%–89%, and 36%–103% respectively, and MDA and O2.- were decreased by 8%–44% and 19%–42% respectively. These findings suggested AMF could protect plants from oxidative stress through increasing activities of antioxidative enzymes to remove reactive oxygen species (ROS). Furthermore, AMF increased Pb accumulation in roots by 1%–19%, but decreased in shoots and substrates (by 45%–53% and 11%–26% respectively). AMF bound most of Pb in roots, declined the transformation from roots to shoots and decreased the accumulation in substrates, which decreased the heavy metal contamination in wetlands. Therefore, AMF played an important role in assisting the Pb transformation of plants in CWs.

Keywords

Arbuscular mycorrhizal fungi, Pb transformation, Constructed wetlands, Heavy metals pollution, Reactive oxygen species, Antioxidative enzymes

Language used: English

Date on which the thesis was submitted / produced: 26. 6. 2020

Thesis defence

• Supervisor: doc. Zhongbing Chen
• Reader: Bo Hu, MSc

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / field:
Geology / Environmental Geosciences