Competencies and Facilities

Micro Respiration
Our Unisense MicroResp equipment is frequently used to assess tissue O₂ consumption in root or shoot segments. It provides reliable O₂ consumption rates for tissue samples as small as 10 mg fresh mass, allowing us to resolve gradients in O₂ consumption along a root. The system can process up to eight samples simultaneously, each incubated in a micro-cuvette with a volume ranging from 0.5 to 4 mL. An optical O₂ sensor moves between cuvettes, and the software calculates O₂ consumption between two time points.

Root anatomy
We have a state-of-the-art Leica VT1200-S vibrating microtome, enabling us to produce high-quality cross-sections of fresh root material. Additionally, we employ histological staining techniques to visualize cell wall components such as lignin and suberin. These cross-sections are then examined using our Nikon Ci-L microscope, which is equipped with LED fluorescence and the relevant excitation and emission filters.

Root architecture
Root architecture is a key trait that responds to abiotic stress but is inherently difficult to assess accurately. However, with our Epson Expression 13000XL Pro, we can scan root systems at up to 1200 × 4800 DPI and process these high-resolution images using RhizoVision. This allows us to classify roots into different categories, calculate root surface area, and perform various other analyses (see here for examples).

Leaf gas films
Leaf hydrophobicity, or leaf gas film formation, is a key trait that contributes to submergence tolerance in many wetland plants, including rice. We have specialized equipment to measure gas film thickness, typically ranging from 5 to 30 µm, using a buoyancy-based approach. Check out this YouTube video, where we explain the measurement process and the required equipment.

Underwater net photosynthesis
Underwater net photosynthesis in submerged plants, including terrestrial species, supplies carbohydrates and O₂ during submergence, making it a critical trait for survival during flood events. We use a vertically rotating incubator with full-spectrum daylight to measure net photosynthesis rates in leaf segments incubated in glass vials under ambient conditions or elevated CO₂ or light. The approach relies on O₂ evolution during the incubation, which is measured with an optical O₂ sensor. Check out this YouTube video if you are curious to see how it works!

Photosynthesis in air
Our group has a brand-new LI-6800 photosynthesis IRGA, which is used to measure net photosynthesis in air. Unlike underwater net photosynthesis, which is based on O₂ evolution, the IRGA measures CO₂ uptake or production. The LI-6800 is portable and suitable for field measurements; however, we primarily use it in our constant-temperature rooms or glasshouse.

Our Li-Cor CO₂ and CH₄ analyzer is one of our most frequently used instruments. We utilize it to assess plant-mediated greenhouse gas fluxes in custom-built flux chambers designed to accommodate our standard pots for both hydroponic and soil-based rice cultures. Additionally, we have developed a system that enables this device to measure soil CO₂ and CH₄ concentrations - an analysis typically conducted using gas chromatography.