Vegetative growth is largely controlled by light; optimum light causes internodes to be

Vegetative growth is largely controlled by light; optimum light causes internodes to be

• A. Longer internodes
• B. No change in internodes
• C. Shorter internodes
• D. Fewer leaves

Answer: (C)

Adequate light signals the plant to grow in a compact, sturdy form, so the spaces between leaves (internodes) become shorter. When light is sufficient, the plant doesn’t need to stretch its stem toward the light, and energy is used to develop leaves and overallstructure, resulting in shorter internodes. This plant response is driven by light receptors that detect intensity and the red to far-red light ratio; the signals under good light conditions actively suppress elongation. In low light, the opposite happens—the plant elongates its stem to try to reach more light, producing longer internodes. Longer internodes, or no change in internode length, don’t fit the idea that optimum light promotes a compact form, and fewer leaves focuses on leaf number rather than stem spacing.

Adequate light signals the plant to grow in a compact, sturdy form, so the spaces between leaves (internodes) become shorter. When light is sufficient, the plant doesn’t need to stretch its stem toward the light, and energy is used to develop leaves and overallstructure, resulting in shorter internodes. This plant response is driven by light receptors that detect intensity and the red to far-red light ratio; the signals under good light conditions actively suppress elongation. In low light, the opposite happens—the plant elongates its stem to try to reach more light, producing longer internodes. Longer internodes, or no change in internode length, don’t fit the idea that optimum light promotes a compact form, and fewer leaves focuses on leaf number rather than stem spacing.