Q36.1-3CC. - Campbell Biology

Question

If you prune a plant’s shoot tips, what will be the short-term effect on the plant’s branching and leaf area index?

 

Step-by-Step Solution

Answer

The pruning of the shoot tips would inhibit apical dominance and favor the growth of lateral shoots from the plant’s axillary buds. This pattern of branching would result in an increased leaf area index and a bushier plant.

Step 1: Apical dominance

In the context of plant biology, apical dominance can be described as the mechanism through which the growth of the plant’s central shoot is dominant over the growth of lateral shoots, and it accounts for the length-wise growth of the plant. The hormone auxin is associated with apical dominance in plants.

Step 2: Leaf area index

The leaves of the plant provide the main bulky appearance to the plant, and the arrangement of leaves determines if a plant has a bushier appearance or not. The leaf area index is a value that indicates the area covered by the plant leaves over a unit area of the ground.

Step 3: Effect of pruning the shoot axis

If the shoot axis of the plant is pruned, the plant will lose its ability of apical dominance; as a result, the growth of the central shoot of the plant would be inhibited, and the growth of the lateral plant branches from the plant’s axillary bud would be favored.

The enhancement of lateral plant branches would result in the bushier appearance of the plant, and it would also result in increasing the value of the leaf area index.