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The role of iron in nodulation and nitrogen fixation in Lupinus angustifolius L
Author(s) -
TANG CAIXIAN,
ROBSON ALAN D.,
DILWORTH MICHAEL J.
Publication year - 1990
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.1469-8137.1990.tb00388.x
Subject(s) - nitrogen fixation , leghemoglobin , chlorosis , lupinus angustifolius , iron deficiency , biology , symbiosis , shoot , nitrogenase , nodule (geology) , phosphorus deficiency , rhizobia , actinorhizal plant , botany , nitrogen deficiency , nitrogen , horticulture , nutrient , root nodule , chemistry , ecology , bacteria , medicine , paleontology , genetics , organic chemistry , anemia
SUMMARY The effects of iron concentration in solution on nodulation and symbiotic N 2 fixation in lupins ( Lupinus angustifolius L. ev. Yandee) were studied in solution culture in the glasshouse by comparing plants supplied with NH 4 NO 3 with those reliant on N 2 fixation. At very low iron supply, adding NH 4 NO 2 did not increase shoot growth. Under moderate iron deficiency, where plants were pale green, adding NH 4 NO 3 increased shoot growth, implying that moderate iron deficiency was, operationally, nitrogen deficiency. Higher iron concentrations in solution were required for maximum growth of plants reliant on symbiotic N 2 fixation than for those supplied with NH 4 NO 3 Iron deficiency depressed nodule initiation earlier than host plant growth, resulting in decreased nodule number and mass. Alleviating iron deficiency enhanced leghaemoglobin production in nodules and increased nitrogen concentrations in the shoots. Iron concentration in the youngest fully expanded leaves provided a good indication of the severity of iron deficiency‐caused chlorosis. The results suggest that iron is involved in symbiotic N 2 fixation through effects on both nodule initiation and nodule function, and that the symbiosis has a higher iron requirement than that needed for host plant growth.