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Cadmium Effects on the Nitrogen Fixation System of Red Alder
Author(s) -
Wickliff Carlos,
Evans Harold J.,
Carter Kevin R.,
Russell Sterling A.
Publication year - 1980
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1980.00472425000900020002x
Subject(s) - nitrogenase , nitrogen fixation , alder , chemistry , shoot , cadmium , horticulture , nitrogen , nutrient , botany , nitrate reductase , zoology , biology , organic chemistry
Red alder ( Alnus rubra Bong.) was grown in sand culture in the greenhouse to obtain data on the effects of cadmium (Cd) on a symbiotic nitrogen (N) fixation system which contributes to the fertility of forest soils. Treatment of red alder seedlings for 11 weeks with 0.545 to 136 µ M CdCl 2 in N‐free nutrient solution decreased in situ nitrogenase activity 25 to 89%, N fixation 23 to 98%, and the number of nodules per plant 29 to 74%, when compared to plants receiving no Cd. Similar reductions were observed in plant growth. Treatment with 0.054 to 0.545 µ M CdCl 2 decreased nitrogenase activity 6 to 31%. When non‐nodulated A. rubra seedlings were inoculated in the presence of 0.054 and 0.109 µ M CdCl 2 , N fixation decreased 52 and 89%, respectively. Plant growth decreased in a similar fashion. When non‐nodulated seedlings were given 0.545 µ M CdCl 2 and 6 mM NH 4 NO 3 or Ca(NO 3 ) 2 , nitrate reductase activity decreased 22 and 24%, respectively, when compared to plants receiving no CdCl 2 . Nitrogen accretion and plant dry weights were decreased by treatments in which plants were supplied with Ca(NO 3 ) 2 and 0.273 and 0.545 µ M CdCl 2 , when compared to controls without CdCl 2 . These results suggest that Cd can inhibit nitrogenase activity and therefore N fixation. Growth, nodulation, and nitrate reductase activity are also inhibited by Cd.