E
Ernie
Guest
Saw a neat poster at the WOC. This might be common knowledge to the plant biologists (I'm a fish biologist by training now doing pharmacy stuff), but apparently salicylic acid plays a very important role in disease resitance in plants. It can be used to induce plants (ie orchids) to fight off viruses essentially by scaring their immune system much like an immunization does in mammals. A young lady presented a nicely done set of experiments at the WOC showing that salicylic acid in concentrations from 0.5-2.0 millimolar were equally very effective (damn near 100%) at preventing two clones of Phals from getting introduced virus over controls. The salicylic acid solution was applied BEFORE the plants were "infected" and then every couple weeks throughtout the experimental period.
What does this mean to us? Ever buy cut flowers and get a little packet of powder with them? That packet is basically ground aspirin.
Well, aspirin is acetylsalicylic acid and we can "break" of the acetyl group by simple hydrolysis (dissolving the aspirin in water). To get the aproximate amount of salicylic acid, one would use about one 81 mg aspirins per quart of water (~1 liter). This would give just over her lowest dose of 0.5 mM, BUT there is *no added benefit* from using the 2 mM dose other than wasting aspirins. I forget the exact timing of her administration, but I recall deciding spraying once a month would be about right from talking with her. I think her intended application was in large, high production commercial operations with a large in/outflux of plants. Less frequent application might be effective in hobby collections? Two things I asked her about were pH of the solutions and phytotoxicity. She did not measure pH, but sal acid is a weak acid and these are low concentrations- check pH before applying, I would NOT apply a solution to my plants if the pH was less than say 4.5 or 5.0. She did not notice any phytotox during the experimental period- doesn't mean years and years of applying aspirin won't catch up with the plants, the jury's still out. Will reduce the risk of heart attacks in your orchids though.
Note that "pure" salicylic acid was used in the original experiments and I have not tried the apsirin solution- I'm not endorsing this practice, just sharing what I read and my interpretation of a hobbyist application.
-Ernie
What does this mean to us? Ever buy cut flowers and get a little packet of powder with them? That packet is basically ground aspirin.
Well, aspirin is acetylsalicylic acid and we can "break" of the acetyl group by simple hydrolysis (dissolving the aspirin in water). To get the aproximate amount of salicylic acid, one would use about one 81 mg aspirins per quart of water (~1 liter). This would give just over her lowest dose of 0.5 mM, BUT there is *no added benefit* from using the 2 mM dose other than wasting aspirins. I forget the exact timing of her administration, but I recall deciding spraying once a month would be about right from talking with her. I think her intended application was in large, high production commercial operations with a large in/outflux of plants. Less frequent application might be effective in hobby collections? Two things I asked her about were pH of the solutions and phytotoxicity. She did not measure pH, but sal acid is a weak acid and these are low concentrations- check pH before applying, I would NOT apply a solution to my plants if the pH was less than say 4.5 or 5.0. She did not notice any phytotox during the experimental period- doesn't mean years and years of applying aspirin won't catch up with the plants, the jury's still out. Will reduce the risk of heart attacks in your orchids though.
Note that "pure" salicylic acid was used in the original experiments and I have not tried the apsirin solution- I'm not endorsing this practice, just sharing what I read and my interpretation of a hobbyist application. -Ernie
