Growth Pouches for High-Throughput Root Phenotyping

Vienna Scientific Instrument offers two different root pouches / germination pouch types:

1. Growth pouch positioning system (classical, "low cost", plastic sleeve Type 1), &
2. Growth pouches with rigid cover panel (Type 2),

Growth Pouch "Type 1". In this cost-effective and efficient root phenotyping growth pouch system, a central acrylic plate (black) is used to hold two germination paper in plastic sleeves (on either site of the Positioning Panel). Hooks at the top of the acrylic panel allow hanging the root pouch system into storage containers/boxes with water/nutrient solution ("PhenoRacks"), allowing the germination paper to re-wet and providing a space effective and organized storage solution. Shading panels prevent light from reaching the roots. Please complete the Growth Pouch Type 1 configuration form (pdf) below for custom root pouch designs, get an instant quote for standard root growth pouch sets (see below), or buy pouch phenotyping sets online. 

Growth Pouch "Type 1" Sets. Two standard sizes of Root Pouches (Type 1)  and custom dimensions are available. 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 of 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 zigzag 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.

Rigid Growth Pouch "Type 2". Some researchers use growing paper-based root pouch systems with acrylic front panels 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 8-10 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 root pouch system, providing some resistance to the growing root system, are root phenoboxes - with a spongy middle layer.

PhenoRacks, designed to provide space-efficient, protected and dark storage for Growth Pouches, hanging (Type 1) or standing (rigid Type 2) in sturdy storage containers with a rail or rack system. PhenoRacks hold 20-30 Root Growth Pouches (one-sided; 40-60 if using both sides of Type 1-positioning panels) depending on size. Continue reading on root PhenoRacks.

Pouch Manipulation Stands, 30° angled (from horizontal), or ~90° (nearly upright). In brief, the vertical growth pouch stand is used when root 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) reduces the risk of damaging shoots - protruding from the top of pouches. The stand is thus used for placement during root sampling, imaging and manipulation. Continue reading on root growth pouch manipulation stands.

How are root pouches / germination paper-based root phenotyping systems generally used? While the exact procedure differs depending on the applied growth pouch system and plant species, in brief, seeds are placed on the wetted germination paper, or seeds are fixated between creped paper and acrylic plates, and then water or a liquid fertilizer solution is added to the bottom of storage containers or bottom 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. Continue reading

Anyhow, eventually, the paper pouch is (en-)closed within a plastic sheet/envelope (growth pouch type "one") or acylic cover (growth pouch type "two") 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. Alternatively, closed plastic envelopes hold a small water reservoir per plant - avoiding cross contamination but requiring more careful watering than bottom reservoirs. Seed germination pouch dimensions should be chosen according to the seed size, the expected root growth (depth and lateral) during the experimental period, and the germination paper-size available. Finally, all types of pouches should be covered by shading panels, dark plastic or aluminum 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; e.g. in a laminar flow cabinet) 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 autoclave germination papers. Darkend root phenotyping pouches are placed under plant lamps or in growth chambers / rooms. Regularly, root systems are imaged with cameras/scanners or root growth and root architecture is measured manually; exposure to light should be as brief as possible. 

Continue to read on how to study rhizobia / nodules in germination pouch phenotyping systems.