The role of leaf water potential in the temperature response of mesophyll conductance
2019; Wiley; Volume: 225; Issue: 3 Linguagem: Inglês
10.1111/nph.16214
ISSN1469-8137
AutoresYong Li, Xin Song, Si Li, William T. Salter, Margaret M. Barbour,
Tópico(s)Photosynthetic Processes and Mechanisms
ResumoSummary Variation in temperature ( T ) is usually accompanied by changes in leaf water potential (Ψ leaf ), which may influence mesophyll conductance ( g m ). However, the effects of Ψ leaf on g m have not yet been considered in models of the g m response to temperature. Temperature responses of g m and Ψ leaf and the response of g m to Ψ leaf were studied in rice ( Oryza sativa ) and wheat ( Triticum aestivum ), and then an empirical model of Ψ leaf was incorporated into an existing g m – T model. In wheat, Ψ leaf was dramatically decreased with increasing T , whereas in rice Ψ leaf was less sensitive or insensitive to T . Without taking Ψ leaf into account, g m for wheat showed no response to T . However, at a given Ψ leaf , g m was significantly higher at high temperature compared with low. After incorporating the function of Ψ leaf into the g m – T model, we suggest that the g m – T relationship can be influenced by the activation and deactivation energy for membrane permeability, Ψ leaf gradient between temperatures, and the sensitivity of g m to Ψ leaf , below a threshold (Ψ leaf,0 ). The data presented here suggest that Ψ leaf plays an important role in the g m – T relationship and should be considered in future studies related to the temperature response of g m and photosynthesis.
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