Biological reasons for being unable to bury rhizome

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Marconis

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We recently had two lectures on plants in my biology course, and the topic of rhizomes came up very briefly. As I was studying, I stopped to wonder, "Why will some plants slowly die if you bury their rhizome?" Obviously, different plants have different rhizomes. Many ferns, as we know, have above ground rhizomes. What makes them so different than those that grow underground?

Well, I emailed my professor. He barely didn't really answer my question and told me that underground rhizomes tend to specialize more in plant propagation, whereas the above ground rhizomes tend to serve as a base point for fronds to grow off of. This makes sense, but it still doesn't answer my question. He told me to come in and look at botany books; when I arrived, he actually seemed irritated (I guess he was busy) when I posed the question about the biological differences between the rhizomes, he didn't really seem like he wanted to talk about it. In the end, he pretty much said, "That's just the way it works."

This answer for me, is not sufficient. I have done countless variations of google searches, and continually find "Just don't bury the rhizome" without any explanation as to why, biologically, the plant will die if you do so. It is frustrating me that I cannot find such information, especially when there must be an answer out there. If the above ground rhizome merely serves as a horizontal stem for leaf/frond growth, why would this function be inhibited underneath the substrate? The leafs are still getting light, and can still grow, so what in the rhizome stops this when buried? Are there respiratory surfaces on a rhizome that I am unaware of, and if so, why are they absent in an underground rhizome? Is there an adaptive value to having an above ground vs below ground rhizome?

If anyone has any information on this, please, share it! Also, if the answer is simple, slap me in the face with it! I just need to know. Thanks!
 
Healthy rhizomes and bulbs
One common problem in the aquarium is rhizomes and bulbs rotting due to lack of oxygen. This is caused when it is buried in the substrate where there is heavy accumulation of decaying organic matter. You can avoid this by leaving the bulb or rhizome above the substrate or burying only enough to keep it rooted.

Robert Paul Hudson's AB Blog

I found a little something.
 
Reading through the article, it basically says that a rhizome is where the crypt stores its energy.

In the wild, crypts grow in places that flood and dry out. Crypt melt and a rhizome allow the crypts to survive. When the conditions change, the leaves melt so the crypt isn't wasting energy by supporting leaves that aren't suited for the new conditions. It uses the energy to grow new leaves that are more efficient.

My knowledge of botany and the chemical processes by which a plant grows is limited, so I don't know what role oxygen plays, other than maybe to stave off other compounds that might damage the crypt.
 
Awesome, thanks BigJim. Would you mind taking a look at my recent thread in general discussion? I highly value your opinion.

Thanks.
 
I always assumed that the material that makes up above ground rhizomes contain chloroplasts, which need light for photosynthesis. If you bury the parts of the plants that contain chloroplasts, no photosynthesis can take place, which means no glucose is produced, which means respiration cannot take place, which would lead to it eventually dieing (much like plant leaves die if not subjected to enough light). Underground rhizomes are not photosynthetic, and are more like a root... they are not green (because they don't contain any chlorophyll thanks to their lack of chloroplasts).
 
Yeah, see, I wasn't aware they contained cells with chloroplasts, as I didn't think they had a reason to. Leaves have chloroplasts as well, as you know. There must be something more going on than chloroplasts/stomatal openings and what not. Stomata on the rhizome is extremely unlikely in an aquatic plant I'd assume. Maybe, though, that would explain the slow decay of the plant as opposed to a rapid dying.

I need to find a botany book with some physiology of rhizomes outlined.

You should have been there during photosynthesis lecture last semester!
 
My line of thinking was if the rhizome is green there is chlorophyll, which means there are chloroplasts.
 
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