Re: How come washing powder can affect the growth of duckweeds?

Hi, 

I am not sure how your duckweeds "met" the washing powder. If the washing 
powder is dissolved, its little molecules will form little micelles, there 
are also salt ions in the solution. Once meet plant cell, the salt will 
distruct the osmotic gradient which is required for cell living, the "little 
micelles" will destroy the cell membrane. Therefore whatever you are 
planting, it will be influenced by the chemicals such as wash powder, 
detergent.

On the other hand, the pollution on the earth is very complex, not only some 
toxic salt, but also sulphite dioxite, chloride gas, nitrate, etc. There are 
different mechanisms on plant, maybe make distruction on cell membrane, 
chloroplast or mitochodia, but all destroy the plant's growth.

Hope it is still helpful.