WPS phenotyping platforms combine a range of unique plant growth and conveyance systems, state-of-the-art imaging stations, high-precision watering and weigh stations. Collectively these features allow clients to quantify plant tolerance and/or vulnerability to a range of induced abiotic stress conditions (e.g. drought, salinity, nutrition and heavy metal stress). Further, the WPS plant growth and conveyance systems encapsulate strategies for imaging changes in both root and shoot phenotypes.
Typical abiotic stress experiments performed on WPS phenotyping platforms include:
- Drought Tolerance and Drought Stress: The WPS watering and weighing module allows the user to accurately deliver water to individual plants or groups of plants according to a schedule of pre-set amounts and delivery options. This allows the user to precisely define and apply strict water regimes within an experiment, and thus have the potential to objectively quantify the effects of various watering regimes on both individual plants and plant groups. Furthermore, the WPS system is able to provide and quantify various watering delivery methods to individual plants or whole populations. This includes application of water directly to pot saucers, the top of plant pots, or through mimicking rain conditions.
To gain valuable insight into plant performance under controlled and simulated drought conditions, WPS can provide physiological assessments such as:
I. RGB Morphometric Imaging that can be reliably used to assess plant growth dynamics, biomass development, plant architecture and leaf curling or drooping in response to adverse abiotic stress conditions such as progressive drought. Chlorophyll fluorescence kinetics provides a key tool for identifying the precise point at which plants begin to respond to stress conditions and the degree to which these conditions inhibit photochemical efficiency.
II. NIR Imaging for monitoring and comparing the water status of plants, or for assessing variations of the water status within different plant tissues. Plants that are adequately hydrated show high absorbance of NIR light in this spectral range 900 and 1700 nm (and low reflectance), whereas those subject to dehydration show greater reflectance in the band. Applying a false color palette to the images allows the researcher to quickly identify plants that are drying rapidly compared to those that are maintaining a healthier water status. In this respect, NIR imaging is important when studying dynamic responses to drought stress and screening for plants with enhanced Water Use Efficiency. WPS Experimental Control Software allows users to track individual plants through an imposed drought cycle so that a time-course of the onset of drought stress and dynamics of response to re-watering can be monitored and quantified.
III. Thermal Imaging uses a sensor to examine water status and stomatal aperture dynamics. Researchers can assess a plant’s responses to heat load and water deprivation through understanding the regulation of stomatal apertures, characterize drought avoidance and self-cooling mechanisms often used under extreme conditions.
IV. Hyperspectral Analysis can be used to quantify water content in water-limited plants.
For example, changes in light-adapted photosynthetic parameters during increasing water deficit can be monitored via chlorophyll fluorescence imaging and used as an early indicator for the rapid identification, assessment and comparison of the relative viability of plants during progressive drought conditions.
- Nutrient Stress: The WPS watering and weighing module is able to deliver a variety of test solutions, for specific applications such as Nitrogen Use Efficiency and Nitrogen Uptake Deficiency. WPS offers multi-sensor analysis to detect color changes that correlate to changes in chlorophyll content, altered growth rates and other morphometric transformations. Changes to root and shoot growth can also be captured.
- Heavy Metal Stress: Environmental pollution can adversely affect plant metabolism (e.g. through damage to the chloroplast and disruption of photosynthesis). Using the WPS phenotyping platforms, heavy metal stress can be examined over a plants entire growth cycle. Stress tolerance and metal homeostasis can be analyzed through RGB imaging. For example, examination of chlorophyll biosynthesis or color changes due to necrosis or through chlorophyll fluorescence kinetic studies to investigate induced structural and functional modifications of photosynthetic machinery within plants.
- Salt Stress: Salinity is a significant factor limiting the productivity of many agricultural crops, with adverse effects on germination, plant vigor and crop yield. The WPS watering and weighing modules allow delivery of precise and accurate levels of water and salt solutions. Senescence, chlorosis, necrosis are all able to be reliably quantified in both the shoot and root biomass.
- Flooding and Water-logging: Water-logging occurs when roots cannot respire due to excess water in the soil profile leading to arrested development and root tissue decomposition. Changes to root and shoot development may be temporally quantified. Further, the suite of WPS imaging solutions allows the recording of effects on both root development whilst concurrently investigating phenotypic changes in the shoot.