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Effects of atmospheric SO 2 on Azolla and Anabaena symbiosis
Author(s) -
Hur JaeSeoun,
Wellburn Alan R.
Publication year - 1993
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1993.tb01761.x
Subject(s) - azolla , anabaena , violaxanthin , botany , heterocyst , biology , fern , antheraxanthin , symbiosis , nitrogenase , lutein , cyanobacteria , nitrogen fixation , carotenoid , bacteria , zeaxanthin , genetics
The water fern Azolla pinnata R. Br. was fumigated for 1 week with either 25, 50 or 100 nl 1 −1 SO 2 . The symbiosis of Azolla with Anabaena azollae (spp.) was severely damaged by atmospheric SO 2 even at concentrations as low as 25 nl 1 −1 , with significant reductions in growth, reduction of C 2 H 2 , NH 3 assimilation, protein synthesis, and heterocyst development. These disturbances appear to be mainly responsible for the extreme sensitivity of this fern to atmospheric SO 2 . Changes in violaxanthin/antheraxanthin and epoxy‐lutein/lutein ratios also indicate that free radical products are induced by atmospheric SO 2 . These results suggest that the Azolla‐Anabaena symbiotic system is a very responsive and reliable lower plant model to study the detailed effects of total sulphur deposition upon the balances between various important plant metabolic processes.