about one year ago, i took part in a laboratory class where we learned various methods related to artificial plant reproduction.
one of the exercises was to create meristem cultures from a carnation plant (dianthus sp.), under sterile conditions.
from each shoot of the plant, we removed the developing leaves on the tip, almost down to the meristem (the few primary cells that constantly divide into more cells). we stopped the exraction at the smallest primordial leaves, placed the tiny piece of plant material on culture medium (in test tubes, under sterile conditions), added a cap to the tube, and sealed it with parafilm.
the following weeks, it was positioned beneath a daylight lamp, and after the experiment was finished, i asked if i could take one specimen home with me.
considering that it’s an almost completely closed system, i didn’t expect little william the carnation to last this long: the plant grew and grew until it reached the top, and i’ve just recently placed it upside down, so that it could grow “upwards” again.
most people don’t consider that, in darkness, plants need to “breathe” just as animals do (as in: use O2 and release CO2), so the gas contents are probably still OK, if only limited. (also, i’m assuming that parafilm isn’t able to stop slow diffusion of gas molecules completely.)
supposedly getting low on fresh nutrients, the plant seems to have given up on the lower leaves so that it could develop new ones. the old, withered leaves do not decompose since there aren’t any microorganisms in the system.