The Arabidopsis Seed Loader (VP 725ZB-3) is a third generation device used by plant geneticists to simplify the task of placing tiny Arabidopsis seeds (0.3 mm by 0.5mm) into 96 well microplates.  By making the loading holes the right shape/diameter/depth and lubricity the seeds fall easily into the holes when the seeds are swirled on the loading plate or "swept" across it.   The dimensions of the holes is very important to achieve only one seed/hole. 

The application of the prototype Arabidopsis Seed Loader is described by Dr. Patrick Krysan in an article describing "Ice-Cap".  A High-Throughput Method for Capturing Plant Tissue Samples for Genotype Analysis."

Click here for a list of published articles that cite the products on this page.

VP 725ZB-3

The VP 725ZB-3 Loading Plate on the right illustrates Arabidopsis seeds in the process of being loaded into the holes.  Gently "sweeping" the seeds over the loading holes ensures that there is only one seed per hole. 

In order to maintain the seeds in the device while loading the holes, a depression is machined into the device to contain the seeds on 3 sides and locate the microplate.  The 4th side is level and the seeds are swept off of it into a catch basin.  

The VP 725ZB-3 consists of 2 plates, a top loading plate with a 96 pattern of loading holes drilled completely through it and a second spring loaded plate that has 96 tiny pins that project into the loading holes.  In the expanded spring condition the pin retreats far enough for one seed to load/hole.  In the depressed spring condition the pin projects through the hole and pushes the seed out.

The Photo to the right illustrates a close-up of the Arabidopsis seeds on the loader plate.   When all the holes are filled, the excess seeds are removed by gently brushing with an artist's paint brush.  This brushing action also removes the top seed from holes that have 2 small seeds in them.

The arrows on the image to the right indicate the plate hole pattern at 9 mm apart. 

The photo on the right illustrates the loading holes after the excess seeds have been brushed away.

Once the VP 725ZB-3 is loaded, a microplate is placed upside down on top and indexed into the blind end of the loader and then both loader and plate are inverted (flipped) and many of the seeds just fall out of the holes and onto agar in the bottom of the wells.

The Plate in the photo is a 1 ml deep well Nunc Plate without a frit and sold as Nunc Part #278012.  In Dr. Krysan's Ice Cap method the frit is replaced by an agar plug which is used to provide nourishment to the seed after it germinates.  This plate can be used without the agar plug to transfer the seeds to other microplates.  This is necessary as the "top print of the Nunc part #278012 is narrower than most microplates (which will not fit in the loader).

Some of the seeds remain in the holes and need to be physically pushed out.  As shown in the photo to the right, when the bottom of the VP 725ZB3 seed loader is pressed, the spring loaded pins push the remaining seeds out of the holes and onto the agar in the microplate wells.    Easy as 1, 2, 3.

Press the play button below to watch an instructional video which demonstrates VP 725ZB3 in action.

Download video (mpeg movie- 30MB)

Press the play button to view the video in a flash format, flash must be installed, or click the download link to download a mpeg version.

We also make drop loaders and flip loaders to dispense balls, disks, bars, dowels and Stir StiXs into 96 and 384 microplates.  We have even made loaders to dispense tiny stir bars (0.0762 mm diameter, 1.00 mm long - VP 718) that are used by NASA to stir colloids in zero gravity.  If we can make these devices, then custom seed loaders for other plant species or microplates can also be made.