Subject: Can you answer a question or two?

From: [email-masked] (Stuart Blood)
Date: 27 Jul 1995 11:52:35 -0700

A friend referred me to this address for a question I have about
plant chemistry.  Can you help me, or tell me who can?

There's a group in my town that's working on building a small 
garden plot at the elementary school.  The idea is that it will be a great
educational tool, and it will involve the community.  We're
planning on building a raised bed in front of the school, not far 
>from  the main driveway.  One of the people involved in the planning
raised the concern about exhaust from buses, which will be idling
next to the garden.  The question is, is there a problem with 
toxins from the exhaust being taken up by plants, either through 
the leaves or the roots?

This first question reminds me of another that I'm not able to
answer.  Some friends who recently moved to the suburbs outside of
Boston were concerned about lead in the soil near there new home
(I don't know if the supposed source is lead paint chips, discarded
building materials, or what.)  They have a small child.  The 
question they had was, are there plants that can absorb heavy 
metals through their roots and concentrate them in the leaves or 
fruit.

Thanks in advance for any information you can offer.
_________________________________________________________________
Stuart Blood
RR1 Box 29 
Thetford Center, VT 05075
(802) 785-4950
[email-masked]

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From: Nicholas Skelton <[email-masked]>
Date: 1 Aug 1995 12:20:15 GMT

I hope this helps
It is only off the top of my head

>exhaust from buses, which will be idling

No not really. There is likely to be more damage caused by wind, soot
coating the leaves and being run over. 

>lead in the soil near there new home......are there plants that can absorb heavy 
metals through their roots and concentrate them in the leaves or 
fruit.
This can happen to a small extent but it would be irrelevant in this
case. I sugest a thick layer of topsoil, not growing vegetables and not
composting. 

I hope this is of interest to you. 

Nick

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From: [email-masked] (Bill Purves)
Date: 2 Aug 1995 04:35:48 GMT

In article <[email-masked]>,
>coating the leaves and being run over. 

... and Nick followed with some very good information.  But it should
be noted that the exhaust DOES present at least one problem itself,
namely ethylene.  Ethylene is among the ingredients of automotive
emissions, and it does affect plants.  The "triple response" to
ethylene includes an inhibition of stem elongation, a screwing up
of gravitropic orientation, and a thickening of the stem.

(bill)

William K. Purves
Department of Biology
Harvey Mudd College
Claremont, CA 91711
[email-masked]