In uk.rec.gardening Oz wrote:

: There have been many studies to show that when plants are attacked by
: pests, levels of toxins rise significantly.

: Even better if one is attacked, it notifies others by emitting
: signalling vapours resulting in unattacked plants jacking their toxin
: level up even though they are not being attacked (yet).

: The diversion of energy into toxins slows plant growth and it is
: believed (like strongly) that this is one reason why fungicide treated
: plants yield more than untreated even in the absence of disease.

: Given that many toxins taste bad (bitter and so on) this may be one
: reason why 'typical' organic veg are reputed taste stronger than non-
: organic. For example mustard oil (a horribly carcinogenic and toxic
: brassica toxin) does taste like very strong mustard.

The brassica toxins normally protect against cancer. They are the reason
broccoli and watercress protect against cancer.

Mustard oil - and especially heated mustard oil - in excess can cause
cancer - e.g.:

http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

....but smaller doses are protective - e.g.:

http://www.ncbi.nlm.nih.gov/entrez/q...&dopt=Abstract

....and the overall effect of brassica toxins on cancer is overwhelmingly
negative.

The problem with the toxins in mustard and its relatives are usually
gastro-intestinal irritation, thyroid problems and possibly anaemia -
rather than cancer.
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|im |yler http://timtyler.org/