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Product LifeRaft
banana potato
By clicking on the pictures you can see them enlarge.
Left Hand Side - banana explants, 4 wks growth;
Right Hand Side - potato microtubers - 5 wks

General Applications:


Multiplication & Elongation and Growth
LifeRaft floats and rafts constitute a unique liquid medium growth system for all forms of plant tissue culture, including multiplication and elongation of nodules, meristem or shoot clumps, microtubers, bulbs and hairy root culture.

Measurement of Secondary Metabolite Production
The liquid medium is easily available for sampling for secondary metabolite production, while the plant material is growing. It may be transferred to a vessel containing fresh medium to continue metabolite production.

Biolistics Regeneration of Callus and other Tissue
The raft support is also excellent for biolistics work, as it provides higher rates of callus and other tissue regeneration, especially in cultures which exhibit strong generation of phenolics at or near the wound site.

How Does LifeRaftTM Work?
A schematic diagram of the LifeRaft system is shown in Figure 1. It consists of three parts:

Figure 1
Figure 1


In addition, to help arrange the plant material on the raft, and keep the base of the culture material in firm contact with the membrane:

The Raft:
The membrane raft, consists of a submicron, microporous membrane film welded to a polypropylene plastic frame. It serves as a floating platform for growth, and assures that the culture has excellent aeration and easy access to nutrients, as shown in Figure 1. The raft is kept afloat slightly above the surface of the liquid medium, by the buoyant float below. Culture material resting on the surface of the membrane draws its nutrients through the liquid filled pores.

Membrane Pore Size:
Two pore sizes of membranes are available:

Physical Size of the Raft:
Both pore size rafts are available in two sizes:
[606 030] [606 250] , or,
  • 90mm x 90mm for LifeGuard vessels.
    • [600 030], [600 250]
    See :Membrane rafts catalog

    The decision on which to use depends on the amount of culture desired for a single vessel.

    Membrane Sterilization and Wetting:
    All of the above mentioned membrane rafts are fully autoclavable and reusable products, which can be autoclaved at 120 C for 20 min.

    Due to the hydrophobic (water repelling) nature of the polypropylene 0.3 micron membrane material, the membrane pores are impregnated with a small amount of a proprietary wetting agent (Osmowet) at the factory. New rafts therefore come ready for sterilization and immediate use. However, after cleaning and drying, these rafts must be treated with wetting agent each time, prior to autoclaving and reuse. Instructions for this procedure are given in the Instruction Manual.     [Raft Instruction Manual]


    The Float:
    As seen in Figure 1, the raft and culture are placed on the Float, which keeps the raft floating at the liquid/air surface as long as the culture weight is within its rated load range. Partly for this reason, the system is called an "interfacial membrane raft".
    A Demo On "interfacial membrane raft"
    When the raft is seated on the corners of the Float, the assembly will float out of the liquid, like a catamaran. By pressing the membrane bottom into contact with the liquid medium, the pores of membrane become filled with liquid, and the membrane surface now "sticks" to the surface of the liquid. The sticking force is provided by the surface tension of the liquid, which acts like a spring, and pulls the membrane film towards it. The float buoyancy is pushing the raft away from the surface, and the resulting balance of forces stretches the surface of the liquid in contact with the raft above the level of the rest of the liquid. For liquid to enter the raft, it has to be literally pulled against gravity by the culture material.

    Float Size and Load Range:
    Floats are made to operate with its size raft (either 55 mm or 90mm square).

    Each is rated for a culture weight load range in which it will keep the raft at the liquid level. Eg. Float     [606 005] , meant for the 55 mm raft, has a rating of 0-5 g, and will stay at the liquid surface from an empty condition up to a total weight of 5 grams of culture.

    In the 90 mm rafts, Float     [602 005] ] has a range of 0 10g . This Float should be used for light culture of up to 2g total weight which is expected to grow up to 7-9 grams over its growth period.

    Float     [602 010]is meant for heavier culture material, with a minimum initial weight of 10g and which is meant to double in weight over the growth period.
    See :Rafts Floats catalog

    The Size of Raft, Culture Container, and Vented Container Lid
    The plant culture container is an important component for successfully using the LifeRaft system. The recommended model size to use depends on the purpose of the work:

    Research
    For many small, different trials, the 55 mm square raft is ideal. Use Magenta GA-3 or 7 type vessel, depending on quantity of medium to be used and anticipated size of the plant.

    Plant Production
    Plant production requires a balance between the number of plants per box (cost of handling, washing, etc) versus the loss incurred if a box becomes contaminated. For plant production, 90mm rafts with LifeGuard Vessels are recommended.
    Vented Lids
    Good aeration is the key to successful growth in most cases, and prevents hyperhydricity (vitrification). The importance of using membrane vented lids together with rafts cannot be overstated.

    The size vent to use again depends on a balance of requirements. By using the largest diameter vent possible, aeration is increased. However, with slow growing plants (> 6 weeks),very high aeration leads to loss of liquid over time and can require the raft to be transferred to a box of fresh medium. The 16 or 22 mm vent diameters are usually desirable for the Magenta size vessel, and 22 or 47 mm diameters are generally optimal for the LifeGuard size vessels.

    Plant Culture Support Accessories (PCSA)
    The PCSA Base Unit is a lightweight polycarbonate plastic form containing a matrix of small culture holder wells, which sits on the membrane surface. It is used to prevent the culture material from falling over, thereby losing good contact between the culture material base and the membrane. It is shown in Figure 2. Two sizes of Base Unit are available:

    PSCA
    Figure 2

    [610 100]
  • 16 sockets in a 4 x 4 matrix for 55 mm rafts
    • [620 100]

    If the culture material is long and spindly in shape, a PCSA cover plate with holes is used with the PCSA. The culture is placed through the hole in the cover plate and stands upright in the well, as shown in     Figure 3. These plates are available with different size holes for each size of Base Unit:

    [610 004]
  • 5 x 5 matrix of 6mm holes
    • [610 006]
  • 4 x 4 matrix of 4 mm holes
    • [620 004]
    See :Rafts Accessories catalog

    PSCA PSCA
    Figure 3



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