Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Diurnal dynamics of photosynthetic parameters of Norway spruce trees cultivated under ambient and elevated CO2
T2 - the reasons of midday depression in CO2 assimilation
AU - Spunda, V.
AU - Kalina, J.
AU - Urban, O.
AU - Luis, V. C.
AU - Sibisse, I.
AU - Puertolas Simon, Jaime
AU - Sprtova, M.
AU - Marek, M. V.
PY - 2005/5
Y1 - 2005/5
N2 - Diurnal courses of net CO2 assimilation, non-assimilatory processes, electron transport rate, photosystem (PS) II photochemical efficiency, and pigment composition were investigated during summer days for sun exposed needles of Norway spruce trees grown under ambient (AC) and/or elevated (EC; 700 mu mol (CO2) mol(-1)) atmospheric carbon dioxide concentration ([CO2]). Daily courses of net CO2 assimilation (AN c,) documented significantly higher values for trees cultivated under EC conditions at irradiances above 250 mu mol m(-2) s(-1). In comparison with the AC variant, EC treatment led to the diminution of midday photosynthesis depression that was predominantly caused by stomatal closure and subsequent decrease of intercellular [CO2] (Ci). A partial recovery of assimilation ability of AC shoots correlated with the partial restoration of stomatal conductivity during the afternoon hours. On the contrary, maximum depression of light-saturated assimilation rate (A(Nmax)), permanent decrease of assimilation capacity (A(Nsat)) over the day and an atypical daily course of gross photosynthesis (P-act) suggested an increased contribution of non-stomatal processes in a down-regulation of carboxylation efficiency in EC shoots during the noon and afternoon hours. The relatively high potential quantum yield of PS II photochemistry (F-V/F-M >= 0.8), estimated on both AC and EC dark adapted needles throughout the day, confirmed that PS II photoinhibition was not the primary reason of the midday depression of photosynthesis. However, the feedback effects of enhanced down-regulation of photosynthesis under EC induced: (a) slight inactivation of PS II and reduction of PS II electron transport rates, (b) enhanced demand on xanthophyll dependent non-radiative dissipation of excess light energy (accumulation of deepoxidized antheraxanthin and zeaxanthin), (c) adjustment of the light harvesting complexes (increase of chlorophyll a/b ratio). (c) 2005 Elsevier Ireland Ltd. All rights reserved.
AB - Diurnal courses of net CO2 assimilation, non-assimilatory processes, electron transport rate, photosystem (PS) II photochemical efficiency, and pigment composition were investigated during summer days for sun exposed needles of Norway spruce trees grown under ambient (AC) and/or elevated (EC; 700 mu mol (CO2) mol(-1)) atmospheric carbon dioxide concentration ([CO2]). Daily courses of net CO2 assimilation (AN c,) documented significantly higher values for trees cultivated under EC conditions at irradiances above 250 mu mol m(-2) s(-1). In comparison with the AC variant, EC treatment led to the diminution of midday photosynthesis depression that was predominantly caused by stomatal closure and subsequent decrease of intercellular [CO2] (Ci). A partial recovery of assimilation ability of AC shoots correlated with the partial restoration of stomatal conductivity during the afternoon hours. On the contrary, maximum depression of light-saturated assimilation rate (A(Nmax)), permanent decrease of assimilation capacity (A(Nsat)) over the day and an atypical daily course of gross photosynthesis (P-act) suggested an increased contribution of non-stomatal processes in a down-regulation of carboxylation efficiency in EC shoots during the noon and afternoon hours. The relatively high potential quantum yield of PS II photochemistry (F-V/F-M >= 0.8), estimated on both AC and EC dark adapted needles throughout the day, confirmed that PS II photoinhibition was not the primary reason of the midday depression of photosynthesis. However, the feedback effects of enhanced down-regulation of photosynthesis under EC induced: (a) slight inactivation of PS II and reduction of PS II electron transport rates, (b) enhanced demand on xanthophyll dependent non-radiative dissipation of excess light energy (accumulation of deepoxidized antheraxanthin and zeaxanthin), (c) adjustment of the light harvesting complexes (increase of chlorophyll a/b ratio). (c) 2005 Elsevier Ireland Ltd. All rights reserved.
KW - elevated CO2
KW - PHOTORESPIRATION
KW - WHOLE-PLANT LEVEL
KW - xanthophyll cycle activity
KW - dynamics of acclimation depression of photosynthesis
KW - XANTHOPHYLL CYCLE
KW - daily course of photosynthesis
KW - CHLOROPHYLL FLUORESCENCE
KW - RETAINED ZEAXANTHIN
KW - stomatal and non-stomatal limitation
KW - photochemical efficiency of photosystem II
KW - GAS-EXCHANGE
KW - ACCLIMATION
KW - LONG-TERM EXPOSURE
KW - LEAVES
KW - DIFFERENT RESPONSES
U2 - 10.1016/j.plantsci.2005.02.002
DO - 10.1016/j.plantsci.2005.02.002
M3 - Journal article
VL - 168
SP - 1371
EP - 1381
JO - Plant Science
JF - Plant Science
SN - 0168-9452
IS - 5
ER -