In this poster, I will show how many questions of plant physiology can be simply explained. Auxin is seen as made when there are good shoot growing conditions: when any cell is receiving a good supply of sugar, CO2, and O2. Conversely gibberellin (GA) is seen as made in cells under poor shoot conditions: the scarcity of a supply of sugar, CO2, and O2. Cytokinin is seen as made under good root conditions: a good supply of water and minerals. Conversely abscisic acid is seen as made under bad root conditions: a scarcity of water and minerals. Ethylene, as is well accepted, is seen as being made under overall stress conditions. Conversely, I add that brassinosteroid is made under good overall non-stressful conditions. I postulate that positive feedback loops exist which are responsible for both apical dominances and senscence. It has been shown that IAA induces the attraction of all nutrients and hormones, and I postulate that this causes apical dominance. The effect is produced because a bud experiencing excellent growing conditions, will start attracting nutrients and, as mentioned above, this will induce more auxin production, which will induce more nutrient uptake etc. One bud soon dominates this competition, but is kept from starving the rest of the plant of all nutrients because the nutrients follow the "auxin train" down the phloem to the roots. Also ABA, GA, an ethylene induced in secondary buds by their nutrient starvation, may "back" inhibit the auxin production. I believe plants using cytokinin in a similar process, induce apical dominance in the roots. I postulate a positive feedback loop also exists for senescence, because ABA, GA and or ethylene, push nutrients out of cells and the more nutrients pushed out, the more ABA, GA, and ethylene are made. My full paper can be seen at http://www.op.net/~socrtwo/plants.htm.

Key words: Plant Hormone Theory, auxin, cytokinin, ehtylene, abscisic acid, gibberellin