Question

Some plants can detect increased levels of light reflected from leaves of encroaching neighbors. This detection elicits stem elongation, production of erect leaves, and reduced lateral branching. How do these responses help the plant compete?

Short answer

The elongation of the stem would expose the upper leaves to sufficient sunlight. The erection of leaves and reduction of lateral branching would further enhance sunlight exposure and reduce shading from neighbors.

Step-by-step solution

Ecology

Ecology can be defined as the biological branch in which the organisms are studied along with the abiotic conditions of their habitat. It also includes the study of how abiotic factors affect organisms and how different species or the same species affect each other’s survival.

Photosynthesis

Photosynthesis is the physiological mechanism through which the plants prepare organic food molecules by utilizing an inorganic carbon sources and water and light energy from the sun.

This process takes place at the chlorophyll-rich leaf parts of the plant and requires sufficient raw materials (water, carbon dioxide, and sunlight).

Plant response to low sunlight

The leaves of the neighboring plant reduce the exposure to sunlight by reflecting most of the sunlight and creating a shadow; as sunlight is essential for all plants to photosynthesize, the shadowed plant modifies itself to reduce competition for sunlight.

The shadowed plant elongates its stem, changes the orientation of its leaves to erect position, and significantly reduces lateral branching of the plant. These modifications reduce the shadowing of the plant from the neighboring plant’s leaves and enhance sunlight exposure, which ultimately reduces resource competition.