From wiki, a list of plant responses to ethylene. Thanks for bringing it up dude, I learned all kinds of new stuff, including how the overwatering response is triggered by ethylene:
Seedling triple response, thickening and shortening of hypocotyl with pronounced apical hook. This is thought to be a seedling's reaction to an obstacle in the soil such a stone, allowing it to push past the obstruction.
In pollination, when the pollen reaches the stigma, the precursor of the ethylene, ACC, is secreted to the petal, the ACC releases ethylene with ACC oxidase.
Stimulates leaf and flower senescence
Stimulates senescence of mature xylem cells in preparation for plant use
Inhibits shoot growth except in some habitually flooded plants like rice
Induces leaf abscission
Induces seed germination
Induces root hair growth – increasing the efficiency of water and mineral absorption
Induces the growth of adventitious roots during flooding
Stimulates epinasty – leaf petiole grows out, leaf hangs down and curls into itself
Stimulates fruit ripening
Induces a climacteric rise in respiration in some fruit which causes a release of additional ethylene. This can be the one bad apple in a barrel spoiling the rest phenomenon.
Affects neighboring individuals
Affects gravitropism
Stimulates nutational bending
Disease/wounding resistance
Inhibits stem growth outside of seedling stage
Stimulates stem and cell broadening and lateral branch growth also outside of seedling stage
Synthesis is stimulated by auxin and maybe cytokinin as well
Ethylene levels are decreased by light
The flooding of roots stimulates the production of ACC which travels through the xylem to the stem and leaves where it is converted to the gas
Interference with auxin transport (with high auxin concentrations)
Inhibits stomatal closing except in some water plants or habitually flooded ones such as some rice varieties, where the opposite occurs (conserving CO2 and O2)
Where ethylene induces stomatal closing, it also induces stem elongation
Induces flowering in pineapples
Yea, that big list of functions is daunting. I can see a little being beneficial to get germination rocking. But I believe I did too much Ethylene. And changing the hormone ratios has domino effects.
