Biochemical defense strategies in sterilized seedlings of Nymphoides peltatum adapted to lead stress.
In order to study potential antioxidant defense mechanisms, the effects of increasing concentrations of lead (Pb) on polyamines (PAs), various thiols, vitamins C and E, and proline contents in sterilized seedlings of Nymphoides peltata (S.G. mel.) Kuntze were investigated after 5 days of exposure. The levels of total putrescine (Put), spermidine (Spd), and spermine (Spm) decreased significantly, while the ratio of (Spd + Spm)/Put first increased but then declined as the concentration of Pb increased. The trends for free, perchloric acid soluble-conjugated (PS-conjugated), and perchloric acid insoluble-bound (PIS-bound) PAs were similar to the trend seen for total PAs. Moreover, reduced glutathione (GSH), nonprotein thiols (NP-SH), phytochelatins (PCs), and vitamin C were induced at high Pb concentrations. No significant change was observed in vitamin E. An initial decline in proline content was followed by an increase as the Pb concentration rose. The reduced level of Put and elevated contents of GSH, NP-SH, PCs, vitamin C, and proline were found to be associated with antioxidant efficiency, which supports the hypothesis that they could play a significant role in the adaptation mechanisms of N. peltatum under Pb stress.
Jiangsu Key Lab of Biodiversity and Biotechnology, College of Life Science, Nanjing Normal University, No. 1 Wenyuan Road, 210046, Nanjing, Jiangsu, People's Republic of China.
Xuqiang
X
Qiao
Guoxin
G
Shi
Xiaoke
X
Yang
Zhenzhen
Z
Zheng
Xiaoying
X
Xu
Haiyan
H
Yang
D000222:Adaptation, Physiological; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007854:Lead / Q000633:toxicity*; D019684:Magnoliopsida / Q000187:drug effects* / Q000378:metabolism; D054811:Phytochelatins / Q000378:metabolism; D011073:Polyamines / Q000378:metabolism*; D011392:Proline / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism; D013095:Spermidine / Q000378:metabolism; D013096:Spermine / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014810:Vitamin E / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D000975:Antioxidants; D011073:Polyamines; D013438:Sulfhydryl Compounds; D014874:Water Pollutants, Chemical; D014810:Vitamin E; D013096:Spermine; D007854:Lead; D054811:Phytochelatins; D011392:Proline; D005978:Glutathione; D001205:Ascorbic Acid; D013095:Spermidine