
TY  - JOUR
A1  - Escalona, J. M. 
A1  - Flexas, J. 
A1  - Medrano, H. 
T1  - Stomatal and non-stomatal limitations of photosynthesis under water stress in field-grown grapevines
JF  - Functional Plant Biology
JO  - Functional Plant Biol.
Y1  - 2000
VL  - 27
IS  - 1
SP  - 87
EP  - 87
KW  - drought, photosynthesis, stomatal and non-stomatal limitations. fluorescence, Coffea arabica, coffee, gas exchanges, photoinhibition, photosynthetic acclimation, xanthophyll cycle.
UR  - https://doi.org/10.1071/PP99019_CO 
N2  - Long-term induced water stress in field-grown grapevine leads to a progressive decline of stomatal conductance, accompanied by a decrease in CO 2 assimilation (40%). The apparent quantum yield also decreases (59%), which may reflect a relative increase in alternative processes for electron consumption. There is also a shift to non-stomatal regulation, as judged from significant depletions (37%) in maximum photosynthesis rate at saturating CO 2 related to limited ribulose biphosphate (RuBP) regeneration, whereas small, non-significant effects are observed on carboxylation efficiency. A high correlation (87%) between photosynthesis and stomatal conductance is observed for all experimental data and declines in intercellular CO 2 concentration parallel reductions in stomatal conductance. The data show that field response of grapevines to increasing soil water deficit involves stomatal and non-stomatal effects but, due to gradually induced drought, regulation mechanisms able to adjust mesophyll capacity to the average CO 2 supply. The non-stomatal adjustment seems to be exerted mainly in metabolic pathways related with the RuBP regeneration. Contrasting characteristics were observed for both cultivars. Tempranillo exploited the non-stressful conditions successfully, whereas Manto Negro, responding to its reputation as more drought resistant, showed a higher intrinsic water use efficiency, particularly for low water availability. This advantage seems to be due to lower non-stomatal limitations. 
ER  -

