Biology Class?

[armenharoutunian]

In biology class we learned that in certain plants if you touch them it stunts their growth, Now i would like to do a science fair project about this, any ideas on how and what i could do it about, and is it true, what is it called and what can i do to experiment. 10th grader.
I WANT TO KNOW IF IT IS TRUE OR NOT, I KNOW ALL MY VARIABLES, ETC. Just want to know is it specific plants or no...

[hahaha]

maybe you could try designing and performing an experiment on this. Find out which plants they're talking about, and try it yourself. Record everything and prsent it at the fair

[Matthew M]

Great idea for a project!

First of all, identify the types of plants that you hypothesize to have this behavior (or phenotype). Then identify some plants that you know don't have that behavior.

You'll need to buy some representative members of these plants, three of the same species should do the trick.

You also need to buy plants that you know will not have their growth stunted by touching them. Pick one species like that, and buy six of them.

Thus:

You have three sets of three plants (9 plants) total.
Set 1: supposed to have it's growth stunted when you touch it (this is your hypothesis).

Set 2: not supposed to be affected when you touch it.

Set 3: a set of plants that you will never touch
(the plants you use should be the same species as those in Set 2)

The experiments might go something like this:

Before you start, measure the length of the stems of all the plants with a piece of string and a ruler (make sure not to touch the plants in Set 3 while you measure, use gloves). Also weigh all the plants in their pots.

Grow the plants all under the same conditions. This means the same amount of water everyday (measure it with a measuring cup), the same size pots, the same amount of sunlight, everything is the same.

Everyday you touch all the plants in Set 1 in a specific way that you will define (i.e. with your whole hand for five seconds). Everyday you also touch the plants in Set 2. But, don't ever touch the plants in Set 3.

After a week or so, again measure the length of the stems of all the plants with a piece of string and a ruler (make sure not to touch the plants in Set 3 while you measure, use gloves). Also weigh all the plants in their pots. Collect data again after the second week doing all the same things you were doing before (same water, touching everyday, etc...).

Congrats, now your done and ready to analyze your data. Find the change in length and weight of the plants between each collection point. Divide the change by the original lengths and weights of the plants to find a percent increase in growth. Average the numbers in Set 1. Average the numbers in Set 2. Average the numbers in Set 3.

Comparing the data from Set 2 and Set 3 should tell you if touching the plant makes a difference in plants you know shouldn't respond to touching. Comparing data in Sets 1 & 2 tells you how much touch stunts the growth of the plants you are interested in.

For sets 2 and 3 try tomato plants (as long as you can cite a book that says touching them doesn't stunt their growth). For Set 1, I think you are look for mustard plants (Arabidopsis). Good luck!