Why callus induction was not so promising in leaf as compared to petiole explants?

Question

Why callus induction was not so promising in leaf as compared to petiole explants?If possible, give the link or website of the source...Kindly thanks to all of u^_^

Answer 1

Callus induction is not based so much on the age of the plant part (as indicated above), but on the process by which the cells of the plant differentiate when introduced to an environment where callus formation can occur.  Every type of plant has different levels of hormones in it that determines the portion of the plant that can be used for propagation.  Sometimes the leaf will have natural hormones in it that will only allow rooting to occur (petunia), other times the petiole will have the same (ficus).

While modern techniques like micropropagation and specialized hormone treatments address these issues, it all boils down to the fact that some parts of the plant just form callus better than others based on hormone concentration levels.

Answer 2

Petiole has actively dividing, young cells therefore when they are put into callus induction medium they continue to divide and form calli. They are very responsive to growth hormones. Whereas leaves (especially mature leaves) contain old and rarely dividing cells. Majority of leaf cells are fully differentiated to perform mainly photosynthesis but not cell division. This makes them unsuitable for callus studies. For some plants however younger, developing leaves can be used for callus induction. (Tobacco leaves for example)