Scientists reported that a fungal pathogen, may negatively a!ect the growth of soybeans (Glycine max). Soybean growth decreased during three years of high rainfall, and the soybean roots were poorly developed. Close relatives of R. anaerobis are plant pathogens and grow in the soil. A lectin-like protein was found in the soil around the soybean roots. is protein may have been secreted by the fungus. Lectins induce mitosis in some root apical meristem tissues. In many instances, rapid cell divisions weaken plant tissues. You have been asked to investigate whether the fungal pathogen lectin a!ects the number of cells undergoing mitosis in a di!erent plant, using root tips.• What is your experimental hypothesis? Your null hypothesis? Are these the same?• How would you design an experiment with onion bulbs to test whether lectinsincrease the number of cells in mitosis?• What would you measure, and how would you measure it?• What would be an appropriate control for your experiment?Your teacher will provide you with untreated and lectin-exposed roots. You should be comfortable identifying cells in mitosis or in interphase before you begin examining the chromosome squashes.

What is your experimental hypothesis?

Experimental hypothesis: If we introduce lectins into the root systems of plants, then they will cause rapid cell division, mitosis, to begin in the root apical meristem tissues which will weaken plant tissues.

Your null hypothesis?

Null hypothesis: If we introduce lectins into the root systems of plants, then there will be no initiation of mitosis in the root apical meristem tissues and the plants will not weaken as a result.

Are these the same?

These are not the same, the experimental hypothesis states that lectin will have an effect on the rate of cell division within the plants which will cause the plant to be weaker, however, the null hypothesis states that lectin will have no effect on the rate of cell division and therefore will not affect the plants overall strength. The null hypothesis is the opposite of the experimental and we are testing the experimental hypothesis to decide whether to accept or reject the null hypothesis.

How would you design an experiment with onion bulbs to test whether lectins increase the number of cells in mitosis?

Assuming these onion bulbs have roots, we would get multiple untreated onions and isolate them by putting them into a controlled environment within a lab by using soil obtained from a store, steady LED light from the room, watered 2 times a day with 2 cups (480 ml) each time and finally isolated the same lab room. The only testable variable in this experiment will be whether the onions are given the lectin or not. In one group we would have the control group, the water they are given would be purely distilled water, however, in another group we would have the experimental group, which would be treated with water mixed with lectin. We are looking to study if there is a change, more specifically an increase, in the cell division of the onion within the treatment/experimental group.

What would you measure, and how would you measure it?

We would need to observe pictures taken of the onion cells under a microscope in order to count the cells in each phase of mitosis. If more cells are visibly undergoing mitosis, and more are present in the picture (density), then we can know that the lectin is causing an increase in rapid cell division. We will compare the amount of cells in each phase with that of the onion which was used as a control.

What would be an appropriate control for your experiment?

An untreated onion that is given distilled water as a treatment, a placebo, which allows us to compare no treatment to the effects of the treatment in the experimental group.

Explanation: I hope the answers are very thorough :) you're welcome future AP Bio students.