Project
Stomatal basis for leaf water use efficiency
Understanding plant responses to climate change requires understanding how the key biological controls on water use, the stomatal pores on leaf surfaces, actually respond to climate and are influenced by their genetically coded structural features. These features can vary based on environment, but their influence on water use and efficiency is still not clear. We combined measurements, modelling and meta-analysis to shed more light on this in different crops and lineages.
Project description
The minimum and maximum stomatal conductance is determined by the structural features of the stomata. Operationally, stomatal pore size changes to determine conductance, limited by size and scaled by density, but the different size-density combinations determine how much structure influences pore dynamics. A log-negative relationship between size and density has been established that is based on leaf tendency to invest in stomatal gas exchange versus the energy costs needed to operate stomatal pore changes, with consensus emerging that high density is best for high gas exchange. However, some studies have found different stomatal anatomical combinations make them more sensitive to drought and dry air, leading to higher water use efficiency but at expense of productivity.
Furthermore, the impact of the stomata on crop and ecosystem function is still described in models primitively but linking anatomy to empirical functions can add more detail into this and provide the starting for extra complexity developing for ecosystem and crop models.
Hence, this project aims to test the effect of changes in stomatal anatomy on water use efficiency specifically based on allometric relationship of leaf size investment and underlying economics, and take this knowledge into anchoring how variation in water use efficiency can be explained as an inherent trait linked to stomatal anatomy, highlighting possible trade-offs. To do this, a combination of microscopic measurements and already existing data, plus a significant meta analysis will be carried out to test these questions in different lineages and crops.
Franks & Beerling, 2009
Objectives and methods
Key questions:
- Do higher stomatal density and smaller size lead to higher conductance? And Photosynthesis?
- And does that correspond with high WUE for all lineages and crops?
- How do different density/size combinations affect stomatal sensitivity to humidity and changes in CO2?
- And can we scale those effects to simulate the effect of anatomy on crop growth or ecosystem function?
- What are the trade-offs and possible future determinants of these allometric relationships, and other anatomical investments, especially with other indicators like LMA.
Key Measurements:
- Stomatal density
- Stomatal size
- Epidermal cell size
- Subsidiary cell size
- Modelling stomatal optimality
- Calculating maximum stomatal conductance
- Modelling Photosynthesis and Transpiration based on stomatal anatomy
- Leaf mass per area and gas exchange from meta-analysis.
Expectations
Student should be willing and capable, after appropriate training, to conduct sampling and data collection by themselves in the lab and understand simple modelling techniques and principles.
Required skills
Understanding of general physiological and ecological principles of plants, alongside willingness to work in the lab and conducting analysis and modelling for a large section of time.
Types of research / work
Work with microscopes and microscope slides, meta-analysis and modelling.
Period
June 2025 - open.
Location
Wageningen campus: Radix Nova and in silico.