ON THE CONTRIBUTION OF MESOPHYLL RESISTANCE TO CO₂ DIFFUSION TO PHOTOSYNTHESIS LIMITATION DURING WATER AND SALT STRESS

We estimated from simultaneous measurements of fluorescence and gas exchange the mesophyll conductance to CO₂ diffusion and the CO₂ concentration in the chloroplasts of spinach leaves exposed to water and salt stress.
Both stresses caused a reduction of mesophyll conductance with respect to controls.
Because of the simultaneous reduction of mesophyll and stomatal conductance the CO₂ concentration in the chloroplasts was also lower than in controls.
Photosynthesis responses to chloroplast CO₂ concentration suggest that diffusive resistances are mainly responsible for photosynthesis limitation of stressed plants at ambient CO₂. However, low photosynthesis in salt stressed leaves at CO₂ higher than ambient indicates that metabolic limitations likely take place when the stress is heavy.

II International Symposium on Irrigation of Horticultural Crops

F. Loreto, S. Delfine, A. Alvino

Resistances to CO₂ diffusion, electron transport, fluorescence, gas exchange, Spinacia oleracea

https://doi.org/10.17660/ActaHortic.1997.449.58