My dead cress

[Doobuzz]

Ok, the background. At school we were tasked with a simple experiment to investigate the effect of fertilisers on plant growth, and have been issued with two (singular) cress plants, one as a control and another to be fed on ammonium sulphate. The problem came about an hour after the lesson when I realised that the (NH4)SO4 one had "keeled over" so to speak. Thinking that perhaps the stem had broken I went back to the lab and replaced it with a fresh stalk. However, upon arriving home I realised that it had done exactly the same thing again. The control is growing quite happily, so what's going on? My best guess is that although I mixed the fertiliser as per the instructions it has somehow poisoned the plant. But if so why?

 

http://picasaweb.google.co.uk/davidcomley.doobuzz/06June28th2007SchoolAndCressPlants/photo#5081231276956772546

 

http://picasaweb.google.co.uk/davidcomley.doobuzz/06June28th2007SchoolAndCressPlants/photo#5081231311316510930

 

I was planning to add gibberellic acid to another sample. Does anyone have any immediate thoughts on what might result? (my best guess is that it will either A. grow slightly larger/faster than a normal plant or more likely B. die) I've found an article detailing an experiment which used mustard seed (http://www.springerlink.com/content/l12w453g31153104/) so I assume it is compatible with the plant in some way.

 

Any ideas?

[ecoli]

out of curiosity... did you mean (NH4)SO3, or ammonium sulfate, which is (NH4)SO4.

[Doobuzz]

did you mean (NH4)SO3, or ammonium sulfate, which is (NH4)SO4.

 

Yep, sorry my mistake - ill edit it in

[Doobuzz]

Ok, the (NH4)SO4 one has started to come back to life

 

Still, any idea what might have caused the problem. I was discussing it with other people at school and they have all had simpilar problems. Does anyone have any idea what might happen to the acid one?

 

Thanks

[Doobuzz]

Duplicate post - please delete