How to Arasystem
By carefully following the instructions in this user's manual, the Arasystem will help you to keep your Arabidopsis seed stocks pure and will save you a great amount of time and labor.
Note that plants that do not grow happily without the Arasystem will also fail to do so with the Arasystem. Therefore it is very important to grow your Arabidopsis plants in optimal conditions.
How to grow your Arabidopsis plants with the Arasystem?
Arabidopsis seeds can be germinated directly in soil or can be transferred to soil after germination in a germination medium. [Recommended soil: a 2/1 mixture of potting compost and sandy soil with artificial moisturing agent. Keep the soil constantly humid.] Plants that have been grown for 3 to 4 weeks on a sucrose medium prior to transfer to soil generally develop better than soil-germinated plants.
Araflats contain 51 pots with an ideal soil volume for growing Arabidopsis to maturity. For optimal aeration of the rosettes, it is advisable to space neighboring Araflats a few centimeters apart.
By using Arabaskets, little baskets that fit into the pots of the Araflats, individual Arabidopsis plants can be moved around at all times.
Aratrays placed underneath the Araflats allow flooding of the plants in growth chamber racks. They also make transportation of plants grown in Araflats more convenient.
How to apply the ARASYSTEM?
The Arasystem is extremely simple to use. At its core is the Aracon, consisting of an Aratube and Arabase. The Aratubes come as plastic sheets that need to be folded into tubes before you can use them. Perhaps it looks difficult at first, but once you have practiced with one or two you will easily fold several hundred in an hour. [Tip: ask undergraduate students in your lab to help folding; alternatively you can easily fold a box of 720 Aracons during a 30 minute coffee break with about 5-6 colleagues.]
Grow Arabidopsis plants until they have a fully matured rosette and the flowering stem is about 10cm high. Once the flowering stem has been formed, the rosette will no longer grow significantly. Generally, the bigger the rosette, the more seeds the plant will produce. In our experience substantially larger rosettes will be formed by keeping the plants in colder conditions (±18 - 20°C) and shorter daylight cycles. The temperature can then be slightly elevated to initiate lowering and seed set.
After the flowering stem is about 10 cm high (and not before), place the Aracon base over the rosette, leaving at least 1cm between the rosette leaves and the bottom of the base. Do not press the Aracon base too firmly onto the rosette. Allow the flowering stem to grow about 10-15 cm out of the top of the inverted cone of the base part of the Aracon.
Now place the folded Aracon tube into the base over the Arabidopsis plant. The tube should be placed so that the two small ventilation holes are placed just above the edge of the Aracon base. The ventilation holes in the tubes are placed asymmetrically, so that aligning all the tubes in the same direction will prevent stems that occasionally grow through these holes from growing into the surrounding tubes.
Allow the plant to grow to maturity, watering the plants regularly by flooding from below. Make sure no water leaks into the Aracons. If greenhouse facilities do not allow flooding of the plants, then use Aratrays. Keep the soil moist but do not leave the plants constantly flooded. Rather, water them once or twice a week, leaving about 1 cm of water in the Aratray. When an Arabidopsis plant starts to grow out of the top of an Aracon tube, decapitate the plant.
When seed set is finished, allow the plants to dry completely. The desiccation process can be enhanced by increasing the temperature a few degrees. Seeds should not be harvested when the plants and the siliques are still green. The immature seeds will adhere to the septa of the siliques and will not fall down easily.
When the plant is completely dry and brown, cut the stem just above the rosette, under the Aracon base. Remove the plant from the Aracon in a pulsating fashion. All the seeds will fall into the Aracon base. Invert the Aracon base over a sheet of paper or over a sieve to separate the seeds from dead silique parts. Collect the seeds in a suitable holder.
Try to prevent insect infestations at all time, as described above. In case of insect infestations, never spray insecticides into the Aracon tubes. The insecticides often contain sticky components that will make seeds stick to the Aracon and which can have a negative effect on Arabidopsis growth.
Avoid condensation in the Aracon at all times. The ventilation holes prevent condensation in normal growth conditions, but condensation can occur in case of high relative humidity, drastic temperature changes, cold air movements and insect infections. Therefore always avoid these conditions in your greenhouse or growth room.