Effects of Exogenous Glycine Betaine on the Physiological Characteristics of Tobacco Seedlings under Low Temperature Stress

PurposeAim to explore the effects of exogenous glycine betaine (GB) on the physiological characteristics and polyphenol metabolism of flue-cured tobacco seedlings under low temperature stress.

MethodThe experiment was carried out with Hongda and K326 as materials, and normal temperature (25 ℃) growth without the application of exogenous GB was used as a positive control (CK), a negative control (CK₀) was performed at a low temperature of 4 ℃ without the application of exogenous GB. Five concentrations of glycine betaine (0.0125, 0.0500, 0.1000, 0.1500 and 0.2000 mol/L) were set for rooting of flue-cured tobacco seedlings under low temperature (4 °C) stress, and the contents of permeate, activity of antioxidant enzymes, polyphenol metabolism related enzymes and total phenol content were measured.

ResultThe application of exogenous GB could affect a series of physiological indexes of tobacco under low temperature stress, including increasing the activities of peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) and polyphenol oxidase (PPO); increasing polyphenol content and phenylalanine ammonia lyase (PAL) activity; increasing the accumulation of soluble sugar and soluble protein; and inhibiting the content of malondialdehyde (MDA) and superoxide anion (O₂⁻) and electrolyte leakage.

ConclusionUnder low temperature stress of 4 °C, 0.1500 mol/L and 0.1000 mol/L of exogenous GB had the greatest alleviation effect to Hongda and K326, respectively.