NAA EXPERMENT -- our final exam
     Last term, our biologic final exam was to write a paper about biology. Dong Xi and I chose this problem: How much NAA does young corn need?


NAA is one kind of vegetal hormone. Of course, it increases the growth of plants. It's widely used, although it has a shortcoming: too much NAA will decrease the growth. But how much is too much? We don't know.


In order to work it out, we prepared some corn seeds and 25g of NAA. It was easy to grow corn in test tubes (the only thing to do is to put sand and water in it). But it's not so easy to solve enough NAA with cold water. The teacher told us we should solve it with alcohol first, then solve this alcohol with water. But when we practised, a lot of sediment suddenly appeared. We tried to drip water slowly drop by drop, but we could not keep it slow enough because we always lost patience. After all, we did it by force: put it directly into water and then boil it with a large electric furnace! Force is really forceful, and NAA does not hate water so much. After the water cooled, we found that NAA solved after an hour of trying!


After this preparation, we put solution of different strength (from 0.005ppm to 500ppm) in each tube. After a week, we measured their length. The corn which got 0.5ppm solution had the longest culm while the corn which got 0.05ppm solution had the longest root.
But our experment is not very exact. If you want to renew our solution, please contact with us.