measuring pH of roots

Vikram Prabhu prabhuv at
Tue Mar 14 16:48:59 EST 1995

Amy J. Harris (ajharris at wrote:

: I am doing research on determining how much plants(grasses) change the pH 
: of the soil around their roots.  I am currently using a standard pH meter 
: and probe.  I am curious if anyone else has done anything like this.  I 
: have read in the literature about microelectrodes but I don't know 
: anything about them.  The hypothesis is that one grass that I 'm studying 
: can pump protons to acidify the surrounding soil so as to make it 
: "easier" to take up minerals such as phosphorous (PO4).  If you have any 
: information about this topic please send it to my e-mail address.

: Thank you,
: ajharris at

Theres plenty of literature on this subject, especially see work by Horst 
Marschner and colleagues. Some very elegant pH experiments have been 
done. Also see the importance of proton pumps etc in Fe nutrition by the 
same group. Many grasses have been shown to excrete phytosiderophores as 
a response to Fe deficiency, which is related to the pH of the rhizosphere.

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