tripsis Posted October 15, 2009 (edited) I've been thinking about vegetative reproduction in cacti recently and how certain clones such as 'Eileen' and 'Yowie', etc are widely distributed and grown. I think it's pretty amazing that a single plant (in terms of genetics) can become so successful due to human interaction. What may have become a single 6m+ giant in its life instead has managed to become probably much larger when adding up all the separate plants which have been cloned of it. Anyway, I'm getting side-tracked here... So with mushrooms, cultures will, over time, undergo senescence and become old, slow and weak, eventually leading to death. Cloning that culture does not lead to fresh vigour as the cells can only undergo division so many times until they die. They are not germ/stem cells and thus do not have the capacity for unlimited division. With plants senescence also plays various roles, from leaf abscission to the hardening of seeds coats, etc. This is somewhat different to the process above though, as it is programmed into specific cells as part of plant growth, leading to apoptosis (programmed cell death) as opposed to ageing. Plants cells are totipotent, meaning most cells within a plant, bar those that are already highly differentiated, are capable of differentiating into any other cell type. This is why any part of the plant can be used to create a callous when culturing and eventually, with the aid of hormones, an entire plant. Germ cells, stem cells and cancer cells all have the ability to keep dividing ad infinitum, as their chromosomes have the ability to continually repair their telomeres, preventing them from senescence. What I'd like to know though, is whether a clone of a specific cactus is more or less immortal, or whether at some point down the line the cells have undergone so much division that they are no longer capable of continuing and thus the clone dies? I'm assuming that plants having totipotent cells does not mean they are like stem cells, as all plants eventually die. But perhaps being able to reproduce asexually bypasses that problem if the right conditions are given? Edited October 16, 2009 by tripsis Share this post Link to post Share on other sites
