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Photosynthesis, carbohydrate levels and chlorophyll fluorescence‐estimated intercellular CO 2 in water‐stressed Casuarina equisetifolia Forst. & Forst.
Author(s) -
SÁnchezRodrÍguez J.,
PÉrez P.,
MartÍnezCarrasco R.
Publication year - 1999
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1046/j.1365-3040.1999.00447.x
Subject(s) - photosynthesis , c4 photosynthesis , fructose 1,6 bisphosphatase , chloroplast stroma , botany , chlorophyll fluorescence , stomatal conductance , chemistry , biology , chlorophyll , fructose , chloroplast , biochemistry , thylakoid , gene
The effect of long‐term water stress on photosynthetic carbon metabolism in Casuarina equisetifolia Forst. & Forst. was analysed by measuring CO 2 assimilation, stomatal conductance, the quantum yield of photosystem II ( Φ PSII ), enzyme activities, and the levels of photosynthetic intermediates and carbohydrates. CO 2 assimilation decreased under water stress while the intercellular CO 2 concentration ( C i ) as estimated by gas exchange measurements remained high. However, the estimates of C i from measurements of Φ PSII suggest that the decrease in photosynthesis can be explained in terms of stomatal closure. Water stress decreased total stromal fructose‐1,6‐bisphosphatase activity and did not alter the activities and activation states of ribulose bisphosphate carboxylase oxygenase and NADP‐dependent malate dehydrogenase (NADP‐MDH). The concentration of photosynthetic metabolites, glucose, fructose and sucrose decreased, whereas starch concentrations increased under drought conditions.