Another attempt at contractile roots

From: George Tinsley <gtinsley at netside.net> on 1997.09.10 at 03:57:04(1209) To put the contractile roots issue into layman's terms, here's my student-minded effort. First check out Krzysztof's page with the picture of the roots coming out of the tuber. http://ng.netgate.net/~kk/Araceae/Amorphophallus/bulbifer.HAM_136.html#bulbifer.HAM_136.3 The roots, which first grow out in length as the ones in KK's picture, have to anchor this big old leaf by themselves so what they do is grow in length to grab deeper into the soil. Then a portion of the roots contract a few millimeters to securely anchor the weight of the leaf above them. The roots grow in length, then contract enough to accomplish what they have to do, so the plant should always be anchored as much as it needs to be. The contraction occurs when cells in the cortex of the root expand sideways and achieve the "accordion look." The entire length of the root doesn't contract, though, so you'll see the bellows in only part of it, probably near the tuber itself. When the outer layer of the tuber rots away, the plant should adjust itself continuously as it needs to because the extra space isn't just created in a few minutes or a day, it takes a while. When the leaf collapses, the tuber doesn't have any reason to go down any farther or fall into a hole because the roots should have had it anchored down as tightly as it needed to be. If the tuber isn't dug up, it starts the process again the following growing season and the new roots anchor it even further as the weight of the leaf requires it. If anyone has anything else to add or correct, please feel free since there are far more knowledgable botany-types on this list. George Tinsley +More Miami, FL

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