Answer:
a. Lower
b. Stimulates
In negative geotropism of shoots, auxin is redistributed to the lower side of the cell, where the amyloplasts have accumulated, where it stimulates cell elongation.
Explanation:
Geotropism can be defined as the direction the various parts of a plant grows toward due to the stimulus which in this case is the force of gravity. Geotropism in plants can be negative or positive.
Negative geotropism occurs when the shoots of a plant grows upwards against the force of gravity.
Answer: downward or lower side : triggers and stimulates
Explanation: In negative geotropism, plant stem tends to move away from gravity. The stem bends upwards against the downward gravitational pull.
Plants stems have hormones called auxins which settle at the bottom/lower part of the cells and allow plants to sense gravity. The auxin also triggers elongation and growth in plant cells.
