5
$\begingroup$

Is the empty space inside a bamboo stem a xylem? And why is the space so large?

$\endgroup$
8
$\begingroup$

No, its not xylem. Bamboo is a grass, and the stem (culm) of many grasses are hollow in the middle (see e.g. Grass Structures from Oregon state for some more info).

The exact reason for why Bamboo have hollow stems is most likely due to evolutionary contingencies. However, from a mechanical stability point of view, a hollow stem is much more rigid and stable than a solid (but much thinner) stem composed of the same amount of biomass (Niklas & Spatz, 2012, p. 191ff). So from the perspective of efficiency, the hollow stems of grasses are very useful. The solid node discs found in grass stems (and in other plants with hollow stems) are however really important for increasing overall stability and ability of stems to resist deformations, while only contributing to a very small amount of the total biomass.

$\endgroup$
  • 2
    $\begingroup$ Interesting. But why is it hollow? $\endgroup$ – AliceD Dec 23 '14 at 11:37
  • 2
    $\begingroup$ @ChrisStronks Because that is the growth pattern of the ancestor of grasses along with current grasses. Why do oaks lack a hollow core? Why do you have 2 ears and not 4? Why do octopus have 8 arms and not 10? Most explanations for these kind of evolutionary contingencies do not have a clear explanation, and most possible explanations will be rather speculative and tentative. $\endgroup$ – fileunderwater Dec 23 '14 at 20:55
  • 3
    $\begingroup$ I'd also suggest that having a hollow stem allows for height to be obtained much more quickly (and therefore access to sunlight in a forest/jungle). A solid stem at the same rate of biomass addition would be about 1/3rd the height of the hollow stem. $\endgroup$ – Frank H. Dec 24 '14 at 6:08

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.