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Photochemical response to drought acclimation in two sunflower genotypes
Author(s) -
Maury Pierre,
Mojayad Fahima,
Berger Monique,
Planchon Claude
Publication year - 1996
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.1399-3054.1996.tb00675.x
Subject(s) - acclimatization , sunflower , photosynthesis , photosystem ii , turgor pressure , helianthus annuus , quenching (fluorescence) , photochemistry , chlorophyll fluorescence , chemistry , electron transport chain , horticulture , biology , agronomy , botany , fluorescence , physics , quantum mechanics
The effects of drought acclimation on CO 2 assimilation and light utilization were investigated in two sunflower genotypes ( Helianthus annuus L., T32 and Viki) in relation to water deficit and/or high light conditions. Drought interaction with PSII efficiency was observed in the genotype T32 with a sustained decrease in the potential photochemical efficiency of PSII, F n /F m . In response to drought acclimation, T32 displayed some tendency to accumulate closed PSII traps (higher value of 1‐qp) without an enhancement of thermal deactivation (Stem‐Volmer non‐photochemical quenching, NPQ). Irrespective of the growth conditions (growth chamber or greenhouse), only Viki was responsive to drought acclimation, with (1) increased net photosynthesis in well‐watered plants, (2) higher maintenance of photochemical electron transfer under water deficit and/or high light, (3) limited PSII inactivation (lower value of 1‐qp) through increased non‐photochemical energy dissipation (Stern‐Volmer NPQ) which was readily reversible even at low leaf water potentials, and (4) higher F v /F m recovery after high light treatment. Additionally, drought acclimation delayed turgor loss during subsequent water stress in Viki. Thus, the response to drought acclimation, with an adjustment of water relations and of energy utilization by PSII, was observed under both growth conditions and was mainly genotype dependent.