Connection between root and branch

[Jimmy Snyder]

It is rather well known that the color of flowers on Hydrangea depends upon the pH of the soil in which it is planted. Low pH in the soil means blue flowers and high pH means pink. Here is a quote from the Texas A&M site on Hydrangea:

Sometimes a single plant may have shades of both pink and blue at the same time due to varying pH in the soil around the plant.

http://aggie-horticulture.tamu.edu/county/smith/homegardens/Shade/hydrangeas.html

Note that the flowers aren't colored a blend of pink and blue, but rather some flowers are pink and some are blue. Could you map the conduits in the plant by selectively altering the pH around individual roots? Does this mean that there is a conduit that goes directly from root to branch? If so, is this true of plants in general? I am thinking of Maple trees in particular. I have a Norway Maple in my yard with a single branch that still has green leaves on it while the rest of the tree is naked. What could cause that?

 

[gerben]

Water in plants is transported from the roots to the leaves through xylem tissue, this consists of long capillaries that go from root to leaf, so different leaves are connected to different parts of the roots and may thus get their water from different regions in the soil.

 

[Jimmy Snyder]

Thanks for the link gerben. I am aware of the xylem and how it acts as a pipe for water. But are these pipes linked up so that there is a one to one relationship between root and branch. If I chop off half the roots of my Norway Maple, will half the branches die?

 

[gerben]

But are these pipes linked up so that there is a one to one relationship between root and branch.

It depends on what exactly you call "one root/branch", but basically yes.

If I chop off half the roots of my Norway Maple, will half the branches die?

yes

 

[Jimmy Snyder]

yes

Thanks for making this clear. Can you point me to a website or book where I can verify this?

 

[gerben]

I think any plant physiology book should make that clear. I did some googling to see if I could find something specific, but did not find much. Here is a quote from a site that did mention something about it:

http://www.floridaplants.com/Reprints/dispelling.htm
...Damaging roots on one side of a tree may cause branch dieback on that side only, or at random throughout the crown. Roots on one side of trees such as oaks and mahogany generally supply the same side of the crown with water and nutrients absorbed through the roots. When roots on one side of a tree are injured, branches on that side often will drop leaves. On other trees such as the maples and rosewood, damage on one side of the root system may cause branch death anywhere in the crown of the tree...