By Paul D. Pruitt
M.A. University of Pennsylvania, Biology, 1986

Introduction

I was reading the Wikipedia articles on Jasmonate, and they do seem to fit the role I had made for Auxin, being the indicator of excess sugar.  This is shown by Jasmonic Acid being involved in tuber formation and de-chlorophylling leaves.  Presumably both these events occur because of an excess of sugar.  So if this is true, perhaps the eight hormone scheme described previously needs rearranging again.

So here's the break down:
Jasmonic Acid - excess sugar indicator.
Gibberellin - sugar deficiency indicator.

Salicylic Acid - excess water indicator.
Abscic Acid - water deficiency indicator.

Cytokinin - excess mineral indicator.
Brassinosteroid - mineral deficiency indicator.

Auxin - excess oxygen (and carbon dioxide?) indicator.
Ethylene - anoxia: oxygen (and carbon dioxide deficiency?) indicator.

One of the problems with this scheme is the Wikipedia Article on Brassinosteroid indicates that Brassinosteroid is transported acropetally.  However, we should expect instead for it to be transported from shoot apex to root.  If I understand what acropetally means, it is traveling in the wrong direction, because mineral deficiency presumably develops in the region furthest from the source of minerals, which would be the apex leaves.

Another problem seems apparent that salicylic and jasmonic acid are not needed to produce a growing callus in tissue culture as one might expect. Neither does it seem to me seem to be involved in crown gall formation as we would anticipate if these hormones were crucial indicator "green lights" for the plant's estimation of whether resources were correct for cell division.  Admittedly, my knowledge of the literature is 20 years old and only updated by Wikipedia...not a very expert position to be in to judge this issue.

Paul D Pruitt - 01/07/2008