Acid Rain and its effect on the growth of sunflowers

[Cricket12381]

Hello all. i know this is probably a very basic question, but I am interested in what effects acid rain normally has on the growth of sunflowers. i have been searching for websites on what a "standard" maybe for the effects of pH 2 and pH4 on the plants. I have come up with nothing. We did a lab for my biology class and from our teachers reactions all of your results are seemingly backwards.

I am hoping that someone can post a link for helpful information on the subject.

Thank you.

[mith]

How did you do your lab? Are you putting acid on the plants or is it mainly affecting soil?

[Cricket12381]

We sprayed the plants as well as pured 50 mL into the soil

[Cat]

I would like to know what acid did you use and if you observed any detrimental effect to sunflowers (if you did what was it). Also, was it one time treatment or was it over some period of time?

[Cricket12381]

I know it was HCL (likely diluted). We did this Monday, Tuesday, and Wednesday over 8 weeks. Around week 5 we had spring break so the greenhouse staff used normal water - everyday. Week 6 we had contamination because someone had continued watering them through at least tuesday.

pH 4 grew the biggest over time. pH 6 was the smallest and showed the most damage. pH 2 responded pretty well in comparison. All three did not grow as much as others or as would be expected. One of my lab partners found some information saying Sunflowers like pH 6 - pH 8.5, but then one of my partners found information stating they have a natural pH 4. When we cut them open and tested the liquid inside 2 had pH 6 and one pH 7. The soil was pH 6 for all three. Our teacher was not sure if the soil has some sort of pH control in hit. He for one did not like using the sunflowers but we had an abundance of sees.

I have continued to search more and more for any information on how they should have reacted since posting this but still have not found any.

[MichaelXY]

The pH of the soil will surely affect the results. A high alkaline soil would neutralize the acidic H2O. My question would be, were your results consistant with the other lab groups. I would think the pH of the soil should have been tested prior to the experiment.

[mith]

The volume of soil used would also affect the effects of the acid. Generally speaking acidic soil gives up more metal ions which is good for growth, however if the plants are well "fed" already this should cause no significant effects. I'd also like to know what kind of damage was observed.

http://209.85.173.104/search?q=cache:_j ... ient=opera

According to this article, the sunflower is one of the more hardy plants(probably why the teach didn't like the choice) and actually your pH applications should not have any significant effects on it.

[MichaelXY]

Good find on the reference Mith.

[Cricket12381]

Other lab groups plants actually died mostly. Only one or two faired better than ours.

If the soil was test beforehand we were not made aware. We were just told to go in fill three pots and plant three to four seeds. It is a very basic experiment really.

The teacher said he prefers using tomato plants. I will pass this information on to my partners. Thanks so much for all your help.

[Cat]

Several things to note:

Sunflower is a lot more hardy than tomato. In my experience with hydroponic responses it shows drastic reaction only to Ca++ deficiency. Also, it would help to note that various cultivars of sunflowers have different soil pH requirements.

Another thing is soil type used. Potting soil that comes with time release fertilizer usually is buffered so the acid poured into it did not do a thing.
The "liquid inside" sunflower is a mixture of phloem (pH 7.3-8) or xylem (pH 5-6.5) exudates. Your pH depends which one you isolated most.

Finally, I would not have expected your experiment to produce any results. You have given your plants a day or two to recover between the treatments.

Here is the web site that should give you some idea about how the experiment should have been conducted and results you should have expected:
http://abacus.bates.edu/~ganderso/biolo ... hotos.html
By the way, HCl is not the best choice for acid rain simulation either.