Which of the following statements best describes road salt injury signs on plants?

• A. Injury on the roots only.
• B. Leaves turning blue in color.
• C. Stem cankers on the root crown only.
• D. Signs may include witches' broom and stem cankers on sides exposed to salt spray.

Answer: (D)

Road salt injury is an abiotic stress from salt spray that shows up where the plant is directly exposed to the salt. Because the spray hits the side of the plant nearest the road, the signs are most obvious on that exposed side. The best description picks up two common responses to this salt stress: witches’ broom, an abnormal proliferation of shoots giving a broomlike look, and stem cankers, damaged, necrotic areas on stems where salt buildup is greatest. These symptoms together reflect the localized above‑ground damage caused by road salt spray.

Other options don’t fit as well because injury from road salt isn’t confined to roots only, and blue coloration isn’t a typical salt‑injury sign. Limiting symptoms to the root crown misses the above‑ground effects on the exposed side, and the specific combination of witches’ broom and stem cankers on the sprayed side provides the most accurate description of road salt injury.