Hi Ranjith,

Greetings!!

What about the 'explant' age? For example, young leaf vs. old leaf. Were these two experiments you conducted using the similar-aged leaf explants? There are some reports saying the 'age' may be a factor. I attached one such paper for your reference. It also mentions that the positions of explants from the donor plants may also be a factor.

Best!

I also want to attach this paper (2009) for you. You can see the paragraph " Effect of age of leaf segment". The results in Table 2. showed that the older the leaf, the less percentage of callus induced.

Plant cells are biological individual. They might behave differently although they are from the same genotype. Sometime there will have some variation from different batch of culture. This might be due to many factors, such as age of explants as mentioned by Yuan Yeu, long-term culture that cause low regeneration capacity of cells, seasonal plant, growth conditions (although in in vitro condition), culture medium, stress factors, etc. 

Hi Ranjith,

As it is pointed out the physiological age is crucial in cell culture or in any other tissue culture for that matter. However once you obtained high regenerating cells you could use the same reserved cells for repeated culture to certain extent since it is same genotype species etc. I used to monitor the physiological age by noting down the germination time or for axillary buds, the bud break time and the explant position in case of leaf.

All the factors mentioned are important, even part of leaf used for explant. For some more you can read "Plant Propagation by Tissue Culture: Volume 1. The Background" edited by Edwin F. George, M. A. Hall, Geert-Jan de Klerk. Springer Science & Business Media, Oct 24, 2007 

Hi Simon

Are you taking the explants from the same plant?? how about age of the plant?? Even in vitro that may be a factor.

Isidro