Help with a HW problem....?

Question

A student read that plants require several essential elements for healthy growth and decided to fertilize his yellowing begonia. When he mixed the plant food, he made the solution 3 times as concentrated as the directions suggested. The next day his plant was not only yellow, but also wilted.


Can you help the student understand his error and suggest a remedy?????

Answer 1

This is really quite easy. The error is in mixing the plant food at triple concentration. This is osmotically hyperconcentrated relative to the osmolality of the intracellular space of the plant's cells, causing water to be osmotically drawn out of the plant cells, causing wilting. This is like spilling too much granular fertilizer on your lawn, causing the grass in that area to die. The remedy is to apply huge amounts of pure water to reduce the osmolality of the soil moisture down to a level that can allow the plant cells to again be able to absorb water.

Answer 2

The plant food puts a greater concentration of hydrophilic material outside the plant than inside. Osmotic pressure will cause the water to move from inside the plant to outside, hydrating the plant food, and making the plant appear wilted.

He's going to have to overwater the plant to compensate (and maybe wash some excess plant food out the bottom of the flowerpot).

Your teacher won't want to hear this, but: begonias are delicate. Sorry, the plant's most likely going to die.

Answer 3

Adding too much food made the soil too acidic, so that the plant could no longer absorb Nitrogen. To restore the proper PH the soil should be flushed with water a few times a week to remove built up salts, and do not fertilize for awhile until the leaves return to a normal color.

Answer 4

I'd tell the student(and you)to study harder and take better notes in class