TY - JOUR
T1 - Does ammonium nitrogen affect accumulation, subcellular distribution and chemical forms of cadmium in Kandelia obovata?
AU - Chai, Minwei
AU - Li, Rongyu
AU - Shen, Xiaoxue
AU - Tam, Nora Fung Yee
AU - Zan, Qijie
AU - Li, Ruili
N1 - Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2018/10/30
Y1 - 2018/10/30
N2 - Heavy metals and nutrients are commonly found in mangrove sediments, but the effect of nutrients on heavy metals in mangrove plants is not clear. A study quantifying the effects of ammonium nitrogen (NH4 +-N) on the accumulation, subcellular distribution and chemical forms of cadmium (Cd) in Kandelia obovata seedlings were conducted. The experiment consisted of four levels of NH4 +-N (0, 10, 50 and 100 mg L−1) in each of which consisted of four Cd levels (0, 1, 5 and 10 mg L−1). The results showed that NH4 +-N magnified the Cd toxicity due to reduced plant biomass, especially with 10 mg L−1 Cd and 100 mg L−1 NH4 +-N supply. NH4 +-N, especially at 100 mg L−1, enhanced the concentration and accumulation of Cd in root but its role on Cd translocation from root to stem and leaf was limited, probably due to low translocation factor. At subcellular level, Cd mainly accumulated in root cell wall but its fractionation depended on Cd levels. Under the stress of 1 and 5 mg L−1 Cd, 50 mg L−1 NH4 +-N supply improved transfer of Cd from root cell wall into cell, and increased pectate and protein integrated forms of intracellular Cd to alleviate Cd toxicity. Under the stress of 10 mg L−1 Cd, NH4 +-N supply promoted the deposition of Cd on root cell wall to restrain its transfer to root cell, which was verified by the reduced levels of pectate and protein integrated forms of Cd in root cell. Thus, NH4 +-N supply improved immobilization of Cd in roots and alleviated Cd toxicity through integration with pectate and protein as well as cell wall combinations in root of K. obovata.
AB - Heavy metals and nutrients are commonly found in mangrove sediments, but the effect of nutrients on heavy metals in mangrove plants is not clear. A study quantifying the effects of ammonium nitrogen (NH4 +-N) on the accumulation, subcellular distribution and chemical forms of cadmium (Cd) in Kandelia obovata seedlings were conducted. The experiment consisted of four levels of NH4 +-N (0, 10, 50 and 100 mg L−1) in each of which consisted of four Cd levels (0, 1, 5 and 10 mg L−1). The results showed that NH4 +-N magnified the Cd toxicity due to reduced plant biomass, especially with 10 mg L−1 Cd and 100 mg L−1 NH4 +-N supply. NH4 +-N, especially at 100 mg L−1, enhanced the concentration and accumulation of Cd in root but its role on Cd translocation from root to stem and leaf was limited, probably due to low translocation factor. At subcellular level, Cd mainly accumulated in root cell wall but its fractionation depended on Cd levels. Under the stress of 1 and 5 mg L−1 Cd, 50 mg L−1 NH4 +-N supply improved transfer of Cd from root cell wall into cell, and increased pectate and protein integrated forms of intracellular Cd to alleviate Cd toxicity. Under the stress of 10 mg L−1 Cd, NH4 +-N supply promoted the deposition of Cd on root cell wall to restrain its transfer to root cell, which was verified by the reduced levels of pectate and protein integrated forms of Cd in root cell. Thus, NH4 +-N supply improved immobilization of Cd in roots and alleviated Cd toxicity through integration with pectate and protein as well as cell wall combinations in root of K. obovata.
KW - Ammonium nitrogen
KW - Cadmium speciation
KW - Kandelia obovata
KW - Mangrove root
UR - http://www.scopus.com/inward/record.url?scp=85050107611&partnerID=8YFLogxK
U2 - 10.1016/j.ecoenv.2018.07.031
DO - 10.1016/j.ecoenv.2018.07.031
M3 - Article
C2 - 30015189
AN - SCOPUS:85050107611
SN - 0147-6513
VL - 162
SP - 430
EP - 437
JO - Ecotoxicology and Environmental Safety
JF - Ecotoxicology and Environmental Safety
ER -