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The impact of elevated ozone and carbon dioxide on young Acer saccharum seedlings
Author(s) -
Gaucher Catherine,
Costanzo Nadine,
Afif Dany,
Mauffette Yves,
Chevrier Normand,
Dizengremel Pierre
Publication year - 2003
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 - 10.1034/j.1399-3054.2003.00046.x
Subject(s) - phosphoenolpyruvate carboxylase , sugar , carbon dioxide , photosynthesis , rubisco , ozone , carbon fixation , saccharum , botany , chemistry , horticulture , zoology , biology , food science , organic chemistry
The effects of high O 3 (200 nl l −1 during the light period) and high CO 2 (650 μl l −1 CO 2 , 24 h a day) alone and in combination were studied on 45‐day‐old sugar maple ( Acer saccharum Marsh.) seedlings for 61 days in growth chambers. After 2 months of treatment under the environmental conditions of the experiment, sugar maple seedlings did not show a marked response to the elevated CO 2 treatment: the effect of high CO 2 on biomass was only detected in the leaves which developed during the treatment, and assimilation rate was not increased. Under high O 3 at ambient CO 2 , assimilation rate at days 41 and 55 and Rubisco content at day 61 decreased in the first pair of leaves; total biomass was reduced by 43%. In these seedlings large increases (more than 2‐fold) in glucose 6‐phosphate dehydrogenase (G6PDH, EC 1.1.1.49) activity and in anaplerotic CO 2 fixation by phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) were observed, suggesting that an enhanced reducing power and carbon skeleton production was needed for detoxification and repair of oxidative damage. Under high O 3 at elevated CO 2 , a stimulation of net CO 2 assimilation was observed after 41 days but was no longer observed at day 55. However, at day 61, the total biomass was only reduced by 21% and stimulation of G6PDH and PEPC was less pronounced than under high O 3 at ambient CO 2 . This suggests that high CO 2 concentration protects, to some extent, against O 3 by providing additional carbon and energy through increased net assimilation.