Details

Autor(en) / Beteiligte

• CANO, F. JAVIER
• LÓPEZ, ROSANA
• WARREN, CHARLES R

Titel

Implications of the mesophyll conductance to CO₂ for photosynthesis and water‐use efficiency during long‐term water stress and recovery in two contrasting Eucalyptus species

Ist Teil von

• Plant, cell and environment, 2014-11, Vol.37 (11), p.2470-2490

Ort / Verlag

Oxford: Blackwell Scientific Publications

Erscheinungsjahr

2014

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• Water stress (WS) slows growth and photosynthesis (Aₙ), but most knowledge comes from short‐time studies that do not account for longer term acclimation processes that are especially relevant in tree species. Using two Eucalyptus species that contrast in drought tolerance, we induced moderate and severe water deficits by withholding water until stomatal conductance (gₛw) decreased to two pre‐defined values for 24 d, WS was maintained at the target gₛw for 29 d and then plants were re‐watered. Additionally, we developed new equations to simulate the effect on mesophyll conductance (gₘ) of accounting for the resistance to refixation of CO₂. The diffusive limitations to CO₂, dominated by the stomata, were the most important constraints to Aₙ. Full recovery of Aₙ was reached after re‐watering, characterized by quick recovery of gₘ and even higher biochemical capacity, in contrast to the slower recovery of gₛw. The acclimation to long‐term WS led to decreased mesophyll and biochemical limitations, in contrast to studies in which stress was imposed more rapidly. Finally, we provide evidence that higher gₘ under WS contributes to higher intrinsic water‐use efficiency (iWUE) and reduces the leaf oxidative stress, highlighting the importance of gₘ as a target for breeding/genetic engineering.