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Flash
439055.  Wed Nov 12, 2008 5:02 pm Reply with quote

There was a thread a while ago which considered the issue of how much bigger than an acorn an oak tree is, and wondered where all the additional material comes from. I think this idea could be developed, but I can't find the thread. Anybody?

 
Sheriff Fatman
439087.  Wed Nov 12, 2008 5:48 pm Reply with quote

Minerals and nutrients from the soil and sugars made by photosynthesis in the trees leaves that are used by the cells in the sapling that comes from the acorn using the internal food sources contained within itself, to help make all the new types of cells that make up the tree.

 
Celebaelin
439267.  Thu Nov 13, 2008 7:47 am Reply with quote

Mind boggling but true - very nearly all the carbon in any plant you care to mention from lowly moss to a giant sequoia comes from carbon dioxide in the air.

A small amount of carbonate ( CO3- ) is drawn up through the roots but that will not be used to form sugars. Sugars in turn are used to form plant polymers, chiefly cellulose and (after some modification) lignin.

 
Flash
439595.  Thu Nov 13, 2008 5:08 pm Reply with quote

So, are we saying that what an acorn does is to conjure up an oak tree literally out of thin air?

 
Celebaelin
439597.  Thu Nov 13, 2008 5:11 pm Reply with quote

Pretty much, yes. There was a famous experiment, or an experiment by a famous person, along these lines but I'll have to look it up to remind myself of who it was who did it; I'm thinking Priestly (the oxygen guy) but maybe not.

Priestly did discover carbon dioxide and oxygen (though he didn't really understand oxygen) amongst other things (and he invented soda water). Can't find a source for him conducting the experiment I meant however.

Quote:
For this invention of soda water, he was elected to the French Academy of Sciences in 1772 and received a medal from the Royal Society in 1773.

Jan Baptist Van Helmont carried out an experiment in which he assigned the increase in mass of a Willow tree grown in a tub over a number of years to water alone. Obviously there is some water but most of the water taken up by plants is lost through transpiration. The increase in dry weight is due almost entirely to carbon dioxide taken from the air (the rest is salts taken from the soil).

Priestly showed that plants consumed carbon dioxide and produced oxygen and I seem to recall it being mentioned that he (re-)interpreted the 'tree in a tub' experiment to indicate that most of the mass comes from CO2 in the air. Maybe you could ask Adam Hart-Davis for a source (I think I remember him as being the presenter of a prog that mentioned it)...

http://en.wikipedia.org/wiki/Joseph_Priestley
http://home.nycap.rr.com/useless/priestly/priestly.html
http://en.wikipedia.org/wiki/Jan_Baptist_van_Helmont

Neither of the Priestly articles are very accurate tbh Priestly's 'dephlogistigated air' was air with the oxygen removed (ie Nitrogen for the most part) not oxygen itself as the Wiki article suggests and the other article confuses Respiration with Photosynthesis; Photosynthesis is this one.

Quote:
Priestley became the first person ever to observe the respiration of plants - the fact that they take in carbon dioxide and release oxygen.


<E> Edits to expand on the poorly remembered experiment and correct typos I spotted.


Last edited by Celebaelin on Thu Nov 13, 2008 6:45 pm; edited 4 times in total

 
Flash
439599.  Thu Nov 13, 2008 5:16 pm Reply with quote

Well, if you find it, let me know, because I think that's a Banker for the show.

 
npower1
439622.  Thu Nov 13, 2008 6:02 pm Reply with quote

Quote:
So, are we saying that what an acorn does is to conjure up an oak tree literally out of thin air?


An answer of yes was given but that can be disputed. There is a symbiosis between trees and bacteria that 'help' the tree extract nutrients from the soil. CO2 from the atmosphere may be a major component that is used but how much of the energy generated by sunlight is attributed to the the capture of carbon by the tree or by the symbiotic bacteria does not appear to have been resolved (and probably varies between tree species).

(Sorry, no sources, but I think my thoughts come from a Singapore forest study.)

 
Celebaelin
439629.  Thu Nov 13, 2008 6:13 pm Reply with quote

See above for more on the experiment - can't find any evidence that anyone ever conducted that experiment and got the interpretation right.

As regards genuine symbiosis of the sort you're implying (or inferring) that's quite rare (legumes mainly) but there are free living nitrogen-fixing bacteria which all plants take advantage of in that they absorb ammonium salts, nitrates and nitrites as a source of nitrogen. Their contribution to the mass of the plant is insignificant however compared with carbon dioxide being converted to sugars and particularly the structural polymers.

http://en.wikipedia.org/wiki/Root_nodule

 
npower1
439645.  Thu Nov 13, 2008 6:56 pm Reply with quote

Quote:

As regards genuine symbiosis that's quite rare (legumes mainly) but there are free living nitrogen-fixing bacteria which all plants take advantage of in that they absorb ammonium salts, nitrates and nitrites as a source of nitrogen. Their contribution to the mass of the plant is insignificant however compared with carbon dioxide being converted to sugars and particularly the structural polymers.


You are suggesting here that my interpretation and understanding of data is wrong. This is bad, of course I'm right. Me stepping back a bit. Oh, look, more information. I will modify my 'theory' to take account of this information. My extrapolation of the data I had was was not informed by later data.

Damn. Is that 'science' working again? Am I allowed to change my mind because I' have more information?

 
Twopints
439656.  Thu Nov 13, 2008 7:37 pm Reply with quote

This makes me wonder about the differences in size between the the size ofoffispring of an organism and it's parent organism at the moment that it seperates from the parent.

Obviously an acorn and a mature oak tree have many orders of magnitude difference in size.

What is the biggest percentage growth rate from "birth" to maturity. Would this be a tree or maybe some sort of fungus where the offspring is a microscopic spore or something completely different?

 
bobwilson
439666.  Thu Nov 13, 2008 8:00 pm Reply with quote

Quote:
As regards genuine symbiosis of the sort you're implying (or inferring) that's quite rare


Half-read this thread and half-remembered this point but - isn't there something about complex cells being a symbiosis of different organisms?

 
bobwilson
439667.  Thu Nov 13, 2008 8:02 pm Reply with quote

Quote:
What is the biggest percentage growth rate from "birth" to maturity. Would this be a tree or maybe some sort of fungus where the offspring is a microscopic spore or something completely different?


I bet it's that thing in Star Trek - the single cell the size of a planet.

 
Celebaelin
439671.  Thu Nov 13, 2008 8:06 pm Reply with quote

npower1 wrote:
Damn. Is that 'science' working again? Am I allowed to change my mind because I' have more information?

Absolutely not. You should adhere relentlessly to your initial view irrespective of any other information or opinion which is presented; that's how all the departmental heads do it.

Twopints wrote:
What is the biggest percentage growth rate from "birth" to maturity. Would this be a tree or maybe some sort of fungus where the offspring is a microscopic spore or something completely different?

How are you assessing growth? By the mass of the Giant Redwood or the sheer diameter of the Honey Fungus? For all I know the mass of the Honey Fungus may even be greater (although this would have to be a very rough guesstimate) but I somehow doubt it.

bobwilson wrote:
Half-read this thread and half-remembered this point but - isn't there something about complex cells being a symbiosis of different organisms?

That's the idea that mitochondria are derived from endocytosed proto-bacteria. We've talked about this before but my memory is sketchy - I've always had difficulty swallowing this (if you'll forgive the pun) but iirc there's quite a lot of supporting evidence been put forward. I'll see if I can find the thread again.

 
Celebaelin
439680.  Thu Nov 13, 2008 8:21 pm Reply with quote

OK, found it (them).

post 129943

post 80176

There is not enough evidence yet to overcome the remarkable footage I've seen tracing a mitochondrial 'strand' as it appeared through a cell and it appearing as essentially a strand of endoplasmic reticulum with cristae. I'll accept that the endosymbiont theory is a possibility but I have a (potentially unreasonable) suspicion that, like most things that people 'know' to be true without being rigorously certain, it probably isn't.

http://en.wikipedia.org/wiki/Endoplasmic_reticulum
http://en.wikipedia.org/wiki/Crista


Last edited by Celebaelin on Thu Nov 13, 2008 8:27 pm; edited 1 time in total

 
bobwilson
439681.  Thu Nov 13, 2008 8:22 pm Reply with quote

Ta -that's exactly what I was thinking of

 

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