Lead and cadmium induced alterations of cellular functions in leaves of Alocasia macrorrhiza L. Schott.
Alocasia macrorrhiza is a fast growing and propagating herbaceous species commonly found in South China. To determine its physiological responses to Pb and Cd stresses, the biochemical, histochemical and cytochemical changes under PbAC2 and CdCl2 phytotoxicity were detected using leaf discs as an experimental model. After leaf discs were infiltrated in different concentrations of PbAC2 and CdCl2 solutions (0, 50, 100, 150, 200 microM) for 72 h, the formation of reactive oxygen species (H2O2 and O2-) in plant tissue were found to be exaggerated together with elevated OH concentration and cell death. Changes in chlorophyll fluorescence (Fv/Fm, PhiPSII, qP and NPQ) imaging colours/areas of leaf discs indicated decreased photosystem II functions by both heavy metal treatments and positive reactions of antioxidants under Pb2+ stress. Results showed that fluorescent detection of hydroxylated terephthlate using terephthalic acid as OH trap is a simple, yet valuable and specific method for monitoring OH generation in plant tissue under heavy metal stresses. As compared with Cd2+, Pb2+ was found to be less toxic, indicating that A. macrorrhiza tissue might have a potential tolerance to Pb.
Liu
Nan
N
South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
Lin
Zhi-Fang
ZF
Lin
Gui-Zhu
GZ
Song
Li-Ying
LY
Chen
Shao-Wei
SW
Mo
Hui
H
Peng
Chang-Lian
CL
D031055:Alocasia / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D002734:Chlorophyll / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000633:toxicity*; D005470:Fluorometry; D007854:Lead / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D010788:Photosynthesis / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D018675:Toxicity Tests
D004785:Environmental Pollutants; D017382:Reactive Oxygen Species; D002104:Cadmium; D002734:Chlorophyll; D007854:Lead