well, not sure what exactly you guys are trying to do with this...but, tissue culture isnt some 'store mothers away for a rainy day' thing, you're not ceasing metabolic processes, and no, it wouldnt be useful for cloning really.
Tissue culture is (normally) used either for micropropagation of plants, or to regenerate transformed plant pieces (explants) used in biotechnology and plant physiology labs. Not trying to sound like a snobby know it all, it's just that this is what I do for a living. Honestly, it really wouldnt serve much purpose for us.
For one, you need a way to sterilize the materials. You'll need a pressure cooker and some sort of laminar flow hood. You'll need to be able to create a sterile growing medium (that 'jelly' is agar, with a specific formulation of sugars, salts, hormones, and probably some housekeeping antifungals) sterile tools, and you'll need to change them to new media every month.
I dont really get what people would want to do with this, if for example you wanted to take a small piece of tissue and regenerate it into a new plantlet...well you could, but the time and trouble (about 3 months from small tissue sample to small regenerating plantlet) hardly seems worth it. You'll need some knowledge of specific hormone ratios to create either roots or shoots, you'll need to subculture the explants at least 3 times before you're done...all the while keeping them absolutely sterile. Even in the lab, with all the equipment and perfect working conditions, we still lose material to contamination.
anyways, if you guys want to know more just ask, i'll be happy to share any info I can.