Deni Bown, Aroids, Century Press, London, 1988.
A couple of days ago I noticed that something was emerging from the sheath (I suppose it is called that way) of my Alocasia... and in fact here it is, the spadix. It is about 4 cm long for the moment, and it is growing quite quickly as far as I can tell. (Is it because of the splendid- though glacial- weather we are experiencing?)
Apparently it was Jean-Baptiste Pierre Antoine de Monet, Chevalier de Lamarck (1744-1829) who noticed for the first time in 1778 (a propos Arum Italicum, in the Flore Francaise, vol. 3, ch. 358) the phenomenon of thermogenesis, i.e. the raising in temperature of the flower in order to attract pollinators. Not that the temperature alone does the trick: when artificially heated but scentless spadices have been used, the insects did not react. The temperature is apparently a way to improve the dispersion of the scent so as to attract pollinators.
Now I do not know if this is going to be the case for my 'Polly', but from a quick search on the Net a number of its cousins (from Alocasia Macrorrhizos to Colocasia Esculenta), not to mention a number of other Aroids, exhibit this type of behavior. Apparently the best way to bring this into evidence is to use liquid crystals to paint the spadix- changes in temperature will then cause changes in color. Would be nice to have some chemistry background...
And by the way, the plants spend an enormous amount of energy increasing the temperatures of their spades- Philodendron Bipinnatifidum apparently uses as much oxygen during the process as a hummingbird. A hummingbird! In order to go through thermogenesis, these plants use the carbohydrates and in some cases lipids (!) stored in the rhizome. This fact may explain the conventional wisdom of eliminating the spadix as soon as it forms, in order for the plant to continue producing the foliage which is the main object of interest for us.
On an Aroid-unrelated note, also my Peperomia Caperata seems to be in high spirits, and has produced what I also would call spadices (if you have a better term for that thing, please let me know what the correct name is.)
There's three of those spadices; here I show two of them. Funny that it seems in such high spirits- recently I had sort of neglected it and let it dry up a bit, and the result were some brownish spots on the tips of the leaves. Must be not too unhappy though...
1 comment:
The part about the energy use was interesting...
Brown spots could be overwatering? I just killed my Janet Craig compacta that way. :( Watered it, and overnight (it was perfectly fine before), the next day every single leaf had huge brown splotches on it and the stem had decayed 70% to the top.
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