Re: [aroid-l] juvenile vs. adult

Dear fellow (I coudn't find your name in the message),

Here follows my contributions to your question. Probably you will get much more then this.


1) Does this happen only to vining aroids?
Nope. Noticeable changes in leaf form also occurs in terrestrial tuberous plants. Leaves in Taccarum warmingii are triangular hastate when young, then it has pinatelly compound leaves. Spathantheum usually have a cordate leaf when young, that are usually deeply incised in mature plants. Sometimes, adult plants can even keep cordate leaves. However, I think that most of the incredible changes occurs in vining aroids, like shingle plants (Monstera).

2) Besides lots of light, does this also require lots of heat and numidity?
I can see no direct relationship, but if you have more heat and humidity, you plant will grow faster! In my experience, if you give a good support for the growing plants (i.e., a totem or a nice tree), it will change from a juvenile plant to an adult plant, whatever the time it takes. I really think that the presence of a stem attached to the substrate is more important than the light. Climbing plants growing with full sun, but no totem, usually will not yield adult stems.

3) So can this be done indoors under home conditions without a greenhouse?
Yes, if you have enough light and a proper totem to climb. Room enough as well!

Can this be done in a greenhouse? Is this strictly for outdoors in >tropical climates?
It CAN be done in a greenhouse, but it is not easy, because some time it needs a lot of growing space. BGs like Kew or Missouri have an interesting apparatus for make climbers grow freely in their scientific collection, but it is not easy and some plants will need usually much more than we can give in a greenhouse.

4) What actually are the basic trigger and mechanism of this change?
Nobody knows exactly. "We" are suspicious that the diameter of the stem is the trigger for the changes in leaf shape (as well for triggering the flowering proccess), but we do not know the trigger for change in diameter. I think that the presence of "excited roots", i.e., roots that were in contact with a substrate and were able to embrace it have a positive effect on the rise of diameter. "Non-excited roots" usually shrinks and probably "say" something to the stem concerning "ok, we do not have a totem, so you better keep slender, long and look for a decent substrate to climb".

5) What is the advantage of this change in evolutionary terms?
There is a real environmental change from the forest ground (where most climbers germinate) to the high canopy. If a plant is able of using better each level That would be a paramount to success in this habitat.

6) Is there a particular book that everybody else learned all this from
already?
I would love to know. If you find it, let me know!


Very best wishes!

Eduardo.


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