Observe the figure and answer the following questions.

a. What changes do you observe in the growth of root and stem in a plant, if it is kept

stationary as shown in the figure for a few days. Why?

b. If the system is rotated continuously and slowly, what change would you observe in its root and stem?

a) If the given setup is kept stationary for a few days then we would observe the growth in the roots downwards.

Because of positive geotropic movement in the roots whereas the stem grows away from the gravity, i.e. shows negative geotropism.

b) If the setup is rotated continuously then there will be no net change in the position of root and stem.

When the system is placed at one position, the roots will start growing downwards. But if the system is rotated, suppose by 180^o, the roots just after rotation will face opposite to the ground. They will again start growing downwards, but after sometime they will again be rotated. Thus, there will be no net change in the position of root and stem, and they will remain parallel to the ground.