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Colonization of wheat para ‐nodules by the N 2 ‐fixing cyanobacterium Nostoc sp. strain 2S9B
Author(s) -
GANTAR M.,
ELHAI J.
Publication year - 1999
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 - 10.1046/j.1469-8137.1999.00352.x
Subject(s) - cyanobacteria , nostoc , strain (injury) , nitrogen fixation , botany , biology , nodule (geology) , nitrogenase , acetylene , bacteria , chemistry , anatomy , paleontology , genetics , organic chemistry
The treatment of wheat roots with 2,4‐dichlorophenoxyacetic acid (2,4‐D) led to the formation of tumour‐like structures, para ‐nodules, which were readily colonized by cyanobacteria. The amount of cyanobacteria found on 2,4‐D treated roots was 3.6 times higher than that found on untreated roots. Cyanobacteria penetrated the para ‐nodules by migrating in between loosely arranged cells that covered their surfaces or by penetrating the space at the junction of root and para ‐nodule. In plants treated with 2,4‐D and co‐cultivated with cyanobacteria in medium without combined nitrogen, the rate of acetylene reduction was three times that seen in untreated but colonized roots. Addition of 2,4‐D itself did not change the rate of acetylene reduction in free‐living culture of Nostoc sp. strain 2S9B. In plants treated with 2,4‐D and co‐cultivated with Nostoc sp. strain 2S9B in medium without combined nitrogen the nitrogen content of roots but not shoots was significantly increased.