Question

Design an experiment that would directly test the hypothesis of the following scenario. Identify the control group, independent variable, and dependent variable.

Hypothesis: The plant species Acidicus plantus grows best at pH 2-4.

Answer 1

ANSWER :-

AIM : To check the optimum temperature for the growth of plant species Acidicus plantus. (Acidic)

HYPOTHESIS :

1. Null Hypothesis : There is no statistically significant relationship between growth rate / germination rate of plant and acidic pH (ranging from 2-4).

2. Alternate Hypothesis : There is a statistically significant relationship between plant growth rate / germination rate and acidic pH value.

REQUIREMENTS :

• Agar plates with plant growth media having pH 2, 4, 7, 10 and 12.
• Petri plates
• Seeds for germination (Acidicus plantus)
• Microscope
• HCL and NaOH (for adjusting pH values)

PROCEDURE :

1. The experiment is carried out at 5 different pH each requiring a set of petriplate provided with agar containing plant growth media.
2. pH can be manipulated by means of addition of NaOH or HCL. The seeds (kept in conditions suitable to overcome dormancy) / saplings are placed in different petriplates with different pH. Equal number of seeds are added (lets consider 20 seeds in each petriplates)
3. The plates are covered and sealed and placed in Plant growth chambers (specifically used to study plant growth).
4. Plants are checked for germination every week and kept under observation. Temperature is kept between 25 to 28 ℃ depending upon CO2 levels.
5. The data observed can be used to calculate the seed germination rate in order to check the optimum pH in which maximum germination occurs.

VARIABLES :

1. Independent Variable : pH can be stated as the independent variable as it can be manipulated.

2. Dependent Variable : Germination rate / Growth rate can be considered as dependent Variable.

3. Control : Seeds grown in agar media having pH 7 can be considered as control group as it is the neutral value whereas other pH are the experimental groups which have either an acidic or an alkaline pH.

​​​​​STATISTICAL TEST TO CHECK THE HYPOTHESIS

This is carried out ( Chi square test ) in order to check whether the null Hypothesis is accepted or rejected depending upon p-value and level of significance.

CONCLUSION : If the null Hypothesis is accepted, the optimum pH for growth is not acidic. If the null Hypothesis is rejected, the plant species grows well at acidic pH of 2-4.

Seed Germination can be considered as an aspect of plant growth as it is the initial step to initiate further growth and flowering in plants that develops from buds. The experiment can also be performed using saplings instead of seeds and can be kept in containers of medium size containing either soil or other growth medium containing substrate followed by keeping the saplings in plant growth chamber. Remaining experiment remains same except the dependent variable becomes growth rate and not germination rate. The growth rate can be calculated by measuring the length of the stem taking an average to find out the optimal pH for growth. This can be represented in terms of hypothesis as mentioned. There is inclusion of alkaline parameters to have better evaluation of the results.