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Elevated CO 2 enhances photosynthetic efficiency, ion uptake and antioxidant activity of Gynura bicolor DC . grown in a porous‐tube nutrient delivery system under simulated microgravity
Author(s) -
Wang M.,
Liu H.,
Dong C.,
Fu Y.,
Liu H.
Publication year - 2016
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/plb.12426
Subject(s) - photosynthesis , antioxidant , biology , rubisco , carboxylation , vitamin c , carotenoid , zoology , botany , food science , biophysics , horticulture , biochemistry , catalysis
It is well known that plants can grow under space conditions, however, perturbations of many biological phenomena have been highlighted due to the effect of altered gravity and its possible interaction with other factors ( e.g ., CO 2 , ion radiation, etc. Our aim was to test whether elevated CO 2 could provide ‘protection’ to Gynura bicolor against the damaging effects of simulated microgravity ( SM ) on photosynthesis, ion uptake and antioxidant activity. As compared to G. bicolor grown in ambient CO 2 with no SM ( ACO 2 ), growth and yield of the plants increased under elevated ambient CO 2 with no SM ( ECO 2 ) and decreased under ACO 2 + SM , whereas there was no significant effect on ECO 2 + SM . Reductions in the content of Chl a , carotenoids and Chl a+b were 17.9%, 20.7% and 17.9% under ACO 2 + SM , respectively, but under ECO 2 there was a significant effect on all photosynthetic pigments except Chl b , compared to ACO 2 . Photosynthesis was improved under ECO 2 with SM and such an improvement was associated with improved water use efficiency and instantaneous carboxylation efficiency. Furthermore, SM caused a reduction in ion absorption rate, except for Ca 2+ , while ECO 2 increased the uptake rate. Finally, the activity of SOD , POD and the content of MDA and H 2 O 2 were enhanced under SM treatments and were highest in ACO 2 + SM . In contrast, T‐ AOC activity and GSH content significantly declined in ACO 2 + SM compared to other treatments. These results suggest that ACO 2 is not sufficient to counteract SM impact, but the increase is usually caused by improvement in CO 2 nutrition in ECO 2 + SM in comparison with ACO 2 + SM .