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15 N 2 FIXATION AND MOLYBDENUM ENHANCEMENT OF ACETYLENE REDUCTION BY LOBARIA SPP.
Author(s) -
HORSTMANN JUDITH L.,
DENISON W. C.,
SILVESTER W. B.
Publication year - 1982
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1982.tb03381.x
Subject(s) - lichen , botany , acetylene , nitrogenase , biology , chemistry , nitrogen fixation , organic chemistry , nitrogen
SUMMARY The lichens Lobaria pulmonaria and Lobaria oregana were assayed for 15 N 2 assimilation in order to confirm previous rates of nitrogenase activity measured by acetylene reduction. In addition, the effect of molybdenum on acetylene reduction activity was studied in both species. The molar conversion ratio (acetylene reduction rate divided by 15 N 2 fixation rate) was 4.27 for Lobaria pulmonaria and 4.78 for Lobaria oregana. The rate of 15 N 2 uptake decreased over time in both species. Addition of 1 p.p.m. molybdenum enhanced acetylene reduction by 180% in Lobaria pulmonaria and by 50% in Lobaria oregana. Optimum enhancement in Lobaria oregana was obtained with 1 p.p.m. molybdenum, while 10 p.p.m. may be inhibitory.