Suresh prepares slides with pollen grains in different sugar concentrations (0%, 2.5%, 5%, 7.5%, 10%) to study the germination of pollen.
What are the different hypotheses which can be tested using this set-up?
Using Suresh's set-up with pollen grains in different sugar concentrations (0%, 2.5%, 5%, 7.5%, 10%), several hypotheses can be tested. The primary hypothesis is whether sugar concentration affects the germination of pollen.
Additionally, we can test if there is an optimal sugar concentration for germination among the provided variations. Another testable hypothesis is whether pollen can germinate in the complete absence of sugar, which can be observed in the 0% concentration slide.
What parameters should be kept the same in this set-up?
To ensure a fair and accurate experiment, several parameters must be kept the same across all the slides. Since the only variable being changed is the sugar concentration, the type of pollen grains used must be identical for every slide.
Furthermore, the volume of the solution placed on each slide, the temperature at which the slides are kept, and the time allowed for the pollen to germinate before observation must all remain constant. Keeping these parameters the same ensures that any observed differences in germination are solely due to the sugar concentration.
Explanation
The question tests the student's understanding of experimental design, specifically regarding forming hypotheses and identifying controlled variables. Since the setup varies the sugar concentration to study pollen germination, the logical hypotheses must relate sugar concentration to the rate or success of germination. For the parameters to be kept the same, students must identify all factors other than the independent variable (sugar concentration) that could affect the dependent variable (germination), such as the source/type of pollen, temperature, time, and volume of solution, ensuring a fair test.