浙江大学学报. 农业与生命科学版 (Feb 2022)
Effects of melatonin and epibrassinolide on the regeneration of long-term subcultured callus of Zoysia matrella (L.) Merr. under simulated drought stress
Abstract
In this study, we explored the effects of exogenous melatonin (MEL) and epibrassinolide (EBL) on the regeneration of callus subcultured for 17 years of Zoysia matrella (L.) Merr. under simulated drought stress, aiming to select the optimal MEL or EBL concentrations that improved the regeneration capacity of callus, and obtain plants with strong drought resistance. The results showed that 0.20 mmol/L MEL markedly promoted the regeneration of callus, and the regeneration rate was 61.1%. Different degrees of drought stress significantly affected the regeneration capacity of callus, and the regeneration rate decreased as polyethylene glycol (PEG) concentration increased. Under 5% and 10% PEG-6000 stress, the regeneration plants of Z. matrella with strong drought tolerance could be obtained. Under 5%-15% PEG-6000 stress, addition of 0.05-0.20 mmol/L MEL or 0.05-0.50 μmol/L EBL promoted the recovery of callus regeneration. Under 10% PEG-6000 stress, 0.20 mmol/L MEL was the best treatment to promote the callus regeneration, and the regeneration rate was as high as 55.6%. High concentrations of MEL and EBL inhibited callus regeneration rates. Moreover, when adding 0.05-0.20 mmol/L MEL under 5% or 10% PEG stress, catalase activity of callus increased markedly; when adding 0.05-0.10 μmol/L EBL, peroxidase, superoxide dismutase activities of callus significantly increased, and the two exogenous hormones evoked response of different antioxidant enzymes during the regeneration of Z. matrella callus. It can be seen that, 0.05-0.20 mmol/L MEL or 0.05-0.10 μmol/L EBL notably promote the regeneration capacity of Z. matrella callus. This study provides new pathways for improving the regeneration capacity of callus in long-term subculture and drought-resistant selection of Z. matrella.
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