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Does elevated CO 2 ameliorate the impact of O 3 on chlorophyll content and photosynthesis in potato ( Solanum tuberosum )?
Author(s) -
Donnelly Alison,
Craigon Jim,
Black Colin R.,
Colls Jeremy J.,
Landon Geoff
Publication year - 2001
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.1399-3054.2001.1110410.x
Subject(s) - photosynthesis , stomatal conductance , carbon dioxide , chlorophyll , horticulture , chemistry , carboxylation , ozone , respiration , chlorophyll fluorescence , chlorophyll a , solanum tuberosum , botany , zoology , biology , biochemistry , organic chemistry , catalysis
This study examined the impact of season‐long exposure to elevated carbon dioxide (CO 2 ) and ozone (O 3 ), individually and in combination, on leaf chlorophyll content and gas exchange characteristics in potato ( Solanum tuberosum L. cv. Bintje). Plants grown in open‐top chambers were exposed to three CO 2 (ambient, 550 and 680 μmol mol −1 ) and two O 3 treatments (ambient and elevated; 25 and 65 nmol mol −1 , 8 h day −1 means, respectively) between crop emergence and maturity; plants were also grown in unchambered field plots. Non‐destructive measurements of chlorophyll content and visible foliar injury were made for all treatments at 2‐week intervals between 43 and 95 days after emergence. Gas exchange measurements were made for all except the intermediate 550 μmol mol −1 CO 2 treatment. Season‐long exposure to elevated O 3 under ambient CO 2 reduced chlorophyll content and induced extensive visible foliar damage, but had little effect on net assimilation rate or stomatal conductance. Elevated CO 2 had no significant effect on chlorophyll content, but greatly reduced the damaging impact of O 3 on chlorophyll content and visible foliar damage. Light‐saturated assimilation rates for leaves grown under elevated CO 2 were consistently lower when measured under either elevated or ambient CO 2 than in equivalent leaves grown under ambient CO 2 . Analysis of CO 2 response curves revealed that CO 2 ‐saturated assimilation rate, maximum rates of carboxylation and electron transport and respiration decreased with time. CO 2 ‐saturated assimilation rate was reduced by elevated O 3 during the early stages of the season, while respiration was significantly greater under elevated CO 2 as the crop approached maturity. The physiological origins of these responses and their implications for the performance of potato in a changing climate are discussed.