Effect of cold acclimation on low-temperature stress in Vicia sativa

To explore the physiological and molecular response mechanisms of common vetch (Vicia sativa) with different cold tolerances to cold acclimation, ‘Lanjian No.1’ (cold sensitive) and ‘Lanjian No.3’ (cold-tolerant) strains were used as experimental materials. Low temperatures were simulated using an artificial climate machine, and one-week-old common vetch seedlings were subjected to 4 ℃ cold stress and 10 ℃ cold acclimations at different times in a turn. The effects of cold acclimation on chlorophyll fluorescence, antioxidant properties, and cold response-related gene expression of common vetch seedlings were investigated. The results showed that, after cold treatment, the chlorophyll fluorescence of the seedling leaves of common vetch decreased. The amounts of malondialdehyde (MDA), soluble sugar (SS), and superoxide dismutase (SOD) and LCHA5 gene expression in ‘Lanjian No.1’ were higher than those in the control group; and the SS, AHP1, LCHA5, IAA14, and FNR gene expressions were significantly (P < 0.05) higher than those in the cold treatment group. The amounts of MDA, SOD, and peroxidase in ‘Lanjian No.3’ were higher than those in the control group, and the gene expressions of MDA, CAT, AHP1, LCHA5, IAA14, and FNR were significantly higher than those in the cold treatment group (P < 0.05). After cold acclimation, the chlorophyll fluorescence F_v/F_m value of ‘Lanjian No.3’ was significantly higher than that of ‘Lanjian No.1’ (P < 0.05); the amounts of MDA, SOD, and CAT of ‘Lanjian No.3’ were also significantly higher than those of ‘Lanjian No.1’ (P < 0.05). IAA14 and FNR gene expressions were also higher in ‘Lanjian No.3’ than in ‘Lanjian No.1’. In conclusion, ‘Lanjian No.3’ showed good osmotic regulation ability during cold acclimation, maintaining high antioxidant enzyme activity and cold-responsive gene expression. The effects of cold acclimation on physiological characteristics were revealed, providing valuable information regarding the anti-cold mechanism of common vetch.