I think that you should look at your plant model, the tissue from which suspension cells originated and obviously your protocol (mediu, , environemntal conditions, # subcultures....). I agree that is a challenging demand. Many you can ckeck in the literature in order to see if something is known for your plant. Have a nice work..........

Maintaining the plant suspension cultures requires lot of care to check the infection and to maintain viability of cells. If it is being maintained for the secondary metabolite production, it looses its quantity and biosynthetic potentiality with the passage of subculturings...... with what aim you want to maintain these cultures and of which plant that also depends.

The same question came to my mind before three years. long term management of suspension culture require proper scientific knowledge.

1. maintenance of stock culture in a specific medium

2. preservation techniques

3. proper subculture

4. proper physical and chemical environment management

5. periodical monitoring of cells

please read this article http://www.ncbi.nlm.nih.gov/pubmed/22289515

and Augereau et al (1986) long term storage of callus culture at low temprature or under mineral oil layer, plant cell report, 5; 372-376

may helpful to you.

how long a tree release O2? some of tree one year. some of tree 20 year. some of tree ....

goodluck..

I used to subculture the suspension cells once in five days, like this i have been maintaining this culture more than 2months (means more than 12 subcullture). Usually there will be some genetic variation in tissue culture but my question is does it affect the plant's main characters like disease resistance, stress tolerance or high yield giving?

I searched articles regarding this doubt but i couldnt get the clear answer,

We have to distinguish loss of regeneration capacity (if this is the aim, for example if you want to use the cell for genetic engineering) and somaclonal variation (SV). Both are depending on species/cultivar/culture method (high concentrations of PGRs are presumed to increseas SV) and even on the cell line. We observe for example that independent cell lines from the same clone differ a lot with respect to SV and loss of regeneration capacity.

Conclusion: you have to test the material regularly; And until now the regeneration of plants is still the only valid way (none of the molecular technique have proven useful to detect abnormalities).

Suggestion: if you would like to preserve your cell line for prolonged periods; use cryopreservation. We use cryopreservation as a standard method to store transformation competent banana cells.

Besides somaclonal variation, the cells may lose their regenerability in the long run. In some case the visual observation of cells under the microscope will give an indication of the viability of cells, the cells with large vacuole and abnormal shape wont be able to regenerate.

Depending on the species, you can maintain your plant for 2 months to 1 year provided you are good in subculturing.

Dear Ashok Kumar Murugesan,

You should confirm that there is a genetic variation or adaption of cells for suspension growth..

If there is a genetic variation that strongly affect the properties of plants. it may increase or decrease the properties.

Generally somaclonal variation occurs due to use of higher concentration of growth regulators for several subcultures.

you are the owner of your plant you should work and say, suspension culture of -------- plant can be maintained ---years without affecting genetic materials.

Dear. ashok Kumar, it depends upon the plant regeneration response of cell suspention culture. If the suspention shows high frequency plant regenration you can maintain it for along time by repeated subculturing at 15 d interval. However, it has been found that organogenic cultures remain viable for long time as compared to somatic embryogenic plants. You have to consider also the population effect in the suspension. Frequency of 50000-100000 cells/ml is OK but more no. of cells may show competitive inhibition on growth and maintenance of cultures.

Please follow the above comments then you may get your answer! And try to understand the objective of maintaining the culture and the ultimate intention of using this culture in your experimental system. So, you have to plan your experimental schedule according to your intention. Ultimate fates of the suspension cell vary even in a single species / CV depending upon the culture system.

Thanks for all. Actually i am going to construct cDNA Library from plant suspension, i planned like, construction of library when culture was one month old culture but because of some issue library construction is getting late. so now suspension cells are some three months old thats why i have this doubt, if i start library work now using this 3 months old culture, will the library represent the plant's actual properties? but ,i know that there will be some genetic variation between a plant and its suspension cells,

Thanks for your suggestion

.

Cryopreservation has been sucessfully developed for cell suspensions, using various methods like encapsulation-dehydration and encapsulatin-vitrification. Results showed that regenerative ability and other traits can be maintained in cryopreserved cells.

Regarding maintenance my own experience while working with cell suspension u canot generalize for time period one has to workout for his plant system.Repeated periodic subculture is good but standrise crupreservation!

I agree with dr. Wang. We systematically use cryopreservation to preserve transformation competent embryogenic cell suspensions of banana. We do this now for more than 10 years and have built up a stock of over 1000 tubes. We have proven that regeneration after 15 year of storage at -196°C is the same if they would have been stored for 1 h in the same conditions.

A simple and well working protocol for such cell suspenions is slow freezing using "Mr Frosty" in the presence of DMSO. For more info see http://www.musalit.org/pdf/IN110412_en.pdf;.

The property of the plants and the species are solely responsible for the maintainance of the suspension culture, you can maintain your plant for 2 months to 6 months by continuing subculture at regular interval