Opportunities for improving leaf water use efficiency under climate change conditions

Area of Science:

• Plant physiology and genetics
• Agricultural science
• Environmental science

Background:

• Intrinsic water use efficiency (WUEi) is vital for plant productivity, especially under changing climate conditions with increased drought and temperature.
• Semi-arid regions face significant challenges to food supply due to climate change, necessitating improved water use efficiency in crops.
• WUEi is a complex trait influenced by multiple physiological processes, making its improvement a multi-disciplinary challenge.

Purpose of the Study:

• To identify leaf traits strongly correlated with intrinsic water use efficiency (WUEi) using a meta-analysis of over 200 C3 plant species/varieties.
• To outline potential biotechnological targets for enhancing WUEi in plants.
• To introduce innovative technologies, such as Unmanned Aerial Vehicles (UAVs), for assessing plant water status at various scales.

Main Methods:

• A meta-analysis was conducted on a dataset comprising over 200 species/varieties and 106 genera of C3 plants.
• Leaf traits related to net photosynthesis (A) and stomatal conductance (gs) were analyzed to determine their correlation with WUEi.
• Emergent technologies, including UAVs with remote sensors, were considered for upscaling water status assessment.

Main Results:

• Increases in the ratios of mesophyll conductance to stomatal conductance (gm/gs) and maximum carboxylation velocity to stomatal conductance (Vcmax/gs) were systematically linked to higher WUEi.
• This relationship was consistent across various species, habitats, and environmental conditions.
• Interactions between photosynthesis, respiration, and metabolomics present further opportunities for WUEi improvement.

Conclusions:

• The study confirms key leaf traits (gm/gs, Vcmax/gs) that can be targeted for enhancing intrinsic water use efficiency (WUEi).
• Biotechnological approaches and advanced technologies like UAVs are promising for improving plant water use efficiency in agriculture.
• The development of 'smart' agriculture, integrating technology for efficient water management and cultivar selection, is emerging as a critical strategy for future food security.