# Ascorbic Acid Priming Boosts Cotton Seed Chilling Tolerance via Membrane Stability and Antioxidant Cycles

## TL;DR

Ascorbic acid treatment helps cotton seeds tolerate cold temperatures by boosting antioxidants and improving germination.

## Contribution

This study reveals how ascorbic acid priming enhances cotton seed chilling tolerance through antioxidant systems and growth-defense trade-offs.

## Key findings

- AsA priming at 50 mg/L for 24 h significantly improved germination metrics under chilling stress.
- AsA-primed seeds showed increased antioxidant enzyme activities (POD, SOD, CAT) and root growth.
- AsA priming activated the Ascorbate–Glutathione cycle and induced a growth-defense trade-off.

## Abstract

Low-temperature stress severely restricts cotton seed germination and seedling establishment, especially in early spring. Ascorbic acid (AsA) priming is a promising strategy to enhance stress tolerance, yet its mechanisms in cotton remain unclear. This study examined the effects of AsA priming on seed germination at 15 °C. Seeds were treated with 0, 25, 50, or 100 mg/L AsA for 3, 6, 12, or 24 h. Results showed that 50 mg/L AsA for 24 h significantly improved germination potential, rate, index, and promptness index (p < 0.05). Compared with water-primed seeds, AsA-primed seeds exhibited greater radicle length (+17.67%) and fresh weight (+136.26%) under chilling stress. This treatment markedly increased antioxidant enzyme activities, including POD (+196.74%), SOD (+43.81%), and CAT (+49.43%), while also promoting the accumulation of Ascorbate–Glutathione cycle-related enzymes and metabolites, thereby reinforcing the antioxidant defense system. Multidimensional statistical analyses further indicated that AsA enhanced root growth by stimulating antioxidant defenses while inducing a trade-off that slightly reduced fresh weight, suggesting a balance between growth and oxidative protection. Overall, AsA priming improves cotton seed cold tolerance by activating enzymatic and non-enzymatic antioxidant systems and mediating a growth–defense trade-off, underscoring its potential as an effective priming agent for early sowing under low-temperature stress.