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REDUCTION OF ACETYLENE AND NITROGEN BY FIELD‐GROWN SOYBEANS
Author(s) -
MAGUE T. H.,
BURRIS R. H.
Publication year - 1972
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.1469-8137.1972.tb04074.x
Subject(s) - acetylene , nitrogen , nitrogen fixation , chemistry , respiration , horticulture , agronomy , botany , biology , organic chemistry
S ummary Acetylene reduction by soybean nodules started without a lag and remained linear with time for about 80 minutes. There was no apparent injury to nodules from evacuation. Rates of reduction of acetylene increased with increasing pO 2 to 1 atm; respiration did not seriously deplete the available O 2 from bottles in which nodules occupied less than 20% of the volume of the bottles. Reduction of acetylene decreased markedly in nodules soaked in water. About 0.2 atm acetylene supported the most rapid reduction of acetylene, and nodules 3–5 mm in diameter were most active. Intact soybean plants, nodulated roots and detached nodules fixed nitrogen at relative rates of approximately 100/46/23. The soybean plants exhibited a diurnal cycle of acetylene reduction dependent upon light intensity and air temperature. The observed ratio of acetylene reduced to N 2 reduced was approximately 2.0 rather than the often assumed theoretical value of 3.0. There was a dramatic difference among soybean varieties in the date of onset and termination of acetylene reduction. Acetylene reduction was most vigorous in plants inoculated with a mixture of effective strains of Rhizobium japonicum.