VSI Growth Pouch Systems. Pouch systems, using plants grown vertically on germination paper, are suitable for screening root system architectures (RSA) of large numbers of seedlings in a rapid and cost-effective manner - allowing for high-throughput (HT) root phenotyping. Lengths, branching and angles of different root types can be measured, which form the basis of models to generate RSAs of crop genotypes and estimate soil exploration and resource uptake.
Growth pouch systems have been successfully applied to seedling screens for many years and species - including bean, maize, wheat, oilseed rape, and pearl millet. The measurement of root traits such as seminal, nodal root numbers and branching angles has shown to hold predictive value for breeding crops with greater yields and stress tolerance. Read more on the application potential of growth pouches.
Vienna Scientific Instrument offers two different growth pouch systems for high throughput, soil-free root phenotyping platforms:
VSI Growth Pouch "Type 1". In this cost-effective and efficient growth pouch system a central acrylic plate (black) is used to hold two germination paper in plastic sleeves (on either site of the plate). Hooks at the top of the acylic plate allow to hang the pouch system into storage containers/boxes with water/nutrient solution ("PhenoRacks"), allowing the germination paper to re-wet. Shading panels prevent light from reaching the roots. Please complete the Growth Pouch Type 1 configuration form for custom pouch designs or get an instant quote for two standard sets (see below).
For Custom designs please send per email: Growth Pouch Type 1 Configuration form (pdf, above) .
VSI Growth Pouch "Type 1" Sets. Two standard sizes of Growth Pouches (Type 1) are currently available. Custom sizes are available on request (Configuration Form). In the sets, 20-30 Pouch Positioning Panels are placed in a storage container equipped with a rail system (see figure; read more: Pouch PhenoRacks). Growth Pouches can be placed on either side of the central acrylic (black, 4mm) positioning panels. Shading panels (1mm, black) fit snugly over the outer surfaces of the pouches; they are slightly narrower to avoid tension at the sides and shorter to match the height to the seed position. Two fixing systems can be used to attach the growth pouches & shading panels to the positioning system, 'rubber bands' or office binder clips (see illustrations). The Positioning Plates have a special zig-zag pattern on the top to hold the rubber bands securely in place. When hanging, the position plates are spaced ~1 cm apart (to avoid disturbing/crushing roots). If desired, germination papers can be tapped into the water/nutrient solution at the bottom of the PhenoRacks, or, when using closed plastic sleeves, a small amount of water/nutrient solution can be stored at the bottom of each pouch.
SET 1 (22.5 x 30 cm)
The "Type 1" Set 1 (suitable for A4 size germination paper) contains:
SET 2 (29 x 38 cm)
The "Type 1" Set 2 (suitable for e.g. 10 x 15 inch germination paper) contains:
Consumables such as germination paper (e.g. from Anchor) and clear plastic sleeves (e.g. from "office depot") can be sourced locally. Contact us or complete the Configuration Form to discuss bespoke growth pouch phenotyping systems (e.g. adapted to different germination paper sizes, species etc.).
Some researchers use growing paper-based pouch systems with acrylic plates and spacers to enclose the germination paper and developing root system. Here, a system frequently used for corn root phenotyping is exemplified, using three to four layers of germination paper and 10 mm spacers - providing sufficient growing space (for large diameter roots), ventilation, and good mechanical protection for the developing root systems. A potentially enhanced version of this rigid growth pouch system, providing some resistance to the growing root system, are root phenoboxes.
VSI Rigid Growth Pouch "Type 2" Set. The standard size of these rigid phenotyping pouches (Type 2) is 25 cm wide x 30.5 cm high - fitting 10 x 12 inch germination paper. Custom sizes are available. For example, ~20x "Type-2-pouches" can be placed in a 40 x 30 x 32 cm storage container. Layers of germination paper can be placed between the acrylic (black) positioning panel (back) and a clear, transparent front panel with spacers attached (screws); standard space between panels is 8 mm (spacers) + germination paper layer thickness. The spacers can be (subsequently) changed by the customer to adapt the phenotyping system to other seed sizes / different numbers of germination papers as required (e.g. fitting 4mm or 10mm spacers). Germination papers are held securely in place by the front panels with spacers pressed against the back panels (using either office binders or rubber bands) - with the paper in between. Additional spacers at the center top / bottom of pouches, preventing the paper from curling/currogating, are optional (and can be positioned as discussed). A shading panel fits snugly over the transparent front panel. The rear and front panels have a special zig-zag pattern to hold rubber bands securely in place. Optional cut-outs (1 x 0.5 cm) at the base of the back panel allow the system to stand in the storage container while the germination paper reliably tap into water or nutrient solution.
The standard "Type 2 " Set (suitable for e.g. 10 x 12-15 inch germination paper) contains:
Consumables such as germination paper (e.g. from Anchor) and clear plastic sleeves ("office depot") can be sourced locally. Contact us to discuss growth pouch phenotying systems (e.g. different sizes, height, storage solutions, etc.).
VSI PhenoRacks. The PhenoRacks are designed to provide space-efficient, protected and dark storage for Growth Pouches, hanging (Type 1) or standing (Type 2) in sturdy storage containers with a rail system. PhenoRacks hold 20-30 Growth Pouches depending on size. Continue reading on PhenoRacks.
VSI Manipulation Stands. Two types of manipulation stands are available for working with Growth Pouches:
In brief, the vertical growth pouch stand is particularly useful when pouches are stored on hanging rails (PhenoRacks) and need to be removed from the containers for set-up, imaging and manipulation. The 30° angled stand (from horizontal, 60° from vertical) reduce the risk of damaging shoots - protruding from the top of pouches. The stand is thus particularly useful for placement during imaging/manipulation. Continue reading on growth pouch manipulation stands.
How are growth pouches generally used? While the exact procedure differs depending on the applied pouch system and species, in brief, seeds are placed on the wetted germination paper, or seeds are fixated between papers and acrylic plates, and then water or a liquid fertilizer solution is added to the bottom of storage containers or sealed pouches. Usually thick creped paper-types are used. Most seeds can be grown in growth pouch systems. In general it is advisable to moisten the paper well before and after placing the seeds. Seeds of some species should be pre-germinated / soaked before being placed. Anyhow, eventually, the paper pouch is (en-)closed within a plastic sheet/envelope (type growth pouch type "one") or acylic cover (e.g. for corn, growth pouch type "two" above) and the growth pouch is placed in an upright (90°) position - the protruding base of the germination paper often taps into a bottom reservoir of water or nutrient solution to re-moist. Growth pouch system dimensions should be chosen according to the seed size, the expected root growth during the experimental period, and the germination paper available. Finally, all types of pouches must be covered by shading panels, dark plastic foil and/or placed in darkend boxes etc. to prevent light reaching the root systems. It is important to work clean (i.e. towards sterile conditions) when preparing the seeds and pouches - as the system is, in the absence of natural antagonists in soil, prone to fungal and bacterial contamination. To minimize fungal growth, it may be helpful to surface sterilize seeds and acylic plates, the germination paper is generally not reusable. Darkend pouches are placed under plant lamps or in growth chambers / rooms. Regularly, root systems are imaged with cameras/scanners or root growth is measured manually; exposure to light should be as brief as possible.