Morphophysiological and biochemical responses of Zinnia elegans L. seedlings to exogenous proline following chilling exposure.

Exogenous proline at 10 mM improves post-chilling recovery of Zinnia elegans seedlings by enhancing growth, water status, and antioxidant responses.

• Why it matters: Low-temperature stress during early growth stages can significantly impair Zinnia elegans, an ornamental species sensitive to chilling, limiting its cultivation and aesthetic value.
• What they did: A factorial experiment applied foliar proline at 0, 5, and 10 mM to seedlings exposed to 3 ± 1 °C for five days, assessing morphological, physiological, and biochemical responses.
• The result: Proline treatment alleviated chilling-induced declines in plant height, root development, water content, and photosynthesis, with 10 mM often yielding the most beneficial effects, indicating improved stress resilience.