How Long Are The Roots Of A Plant ?

[modeller]

I read in a research paper that the total length of roots of a maize plant was 5 km.

It is true that there are thousands of root hairs which you can see under a optical microscope but being as they were each less than a thousanth of a cm in length , it would need 100 million to reach one km , let alone 5.

Even if you add in cells that are less than a billionth of a cm it would require countless billions of them just to add a few cms.

You see similar claims about nerve cells in the human body being 50km. How do they arrive at these figures ?

[Old_Geezer]

I suspect it would depend on the plant in question.

No expert, but the maize claim surprises me. But I guess this is about separating them and laying them end to end, yes ? In which case you wouldn't count cells. You just multiply the average length by the number of, well I want to say root branches, but you know what I mean. Similarly for nerves.

[mibn2cweus]

How long is the coastline of Great Britain?

[Teddio]

Somewhere between 5000 miles and infinity. Possibly something to do with fractals?

[wildwood]

I've read somewhere that if all the DNA in a human body was laid straight out end to end it would reach a distance equal to over 50 trips to the sun and back, s 5km for all the roots of a maize plant doesn't surprise me at all.

[heathfield]

The coastline measurement result depends on the length of your ruler, (work that one out), and yes, it comes down to fractals. I reckon these things are probably worked out by people sitting in offices with little else to do on a Friday afternoon!

[I_Hate_Infinity]

Depends what scale you use, if you count atoms or if you count threads. Nature's full of extra-ordinary conceptual comparisons that seem to defy logic, however if the research paper you read was credible, one must assume accurate measurements were taken and reasonable conclusions were drawn from averaging the data, allowing the author to invert the microscopic scale of root filaments, into an incedible sounding 5km Charity Fun Run length.

My favourite fact about plants is the wrong assumption that they grow from the ground. All the materials they use to build their form is captured from the air :)