The effect of postharvest pre-storage temperature on the wound healing of potato minitubers grown in an aeroponic system was evaluated, and its possible mechanisms were also explored. Potato mini-tubers (cv. Tongshu 1’) free from artificial damage were pre-stored at 4, 15 or 25 ℃ (86%–88% relative humidity) in a dark environment for 20 days. Mass loss rate was measured during pre-storage, the accumulation of suberin and cork in periderm cells was observed, the degree of suberization was examined, and the changes in phenylpropane and reactive oxygen species metabolism in potato tuber periderm were also analyzed. Results showed that pre-storage at 15 ℃ significantly promoted the accumulation of suberin polyphenolics (SPP) and suberin polyaliphatics (SPA) and the degree of suberization in periderm tissue. On the fifth day of pre-storage, the accumulation of SPP and SPA and the degree of suberization in potato tubers prestored at 15 ℃ were higher than those at 4 and 25 ℃ by 50.90% and 26.94% (P < 0.05); 44.89% and 30.23% (P < 0.05); and 27.66% and 8.18%(P < 0.05), respectively. Pre-storage at 15 ℃ also significantly increased phenylalanine ammonia lyase (PAL) activity (P < 0.05), and augmented the contents of total phenols, flavonoids and lignin. On day 5, PAL activity in potato tubers prestored at 15 ℃ was 34.46% and 12.64% higher than that at 4 and 25 ℃, respectively (P < 0.05). The contents of total phenols and flavonoids were 11.93% and 40.05% higher than those at 4 ℃, and 2.72% and 15.50% higher than those at 25 ℃, respectively. On the 20th day, the content of lignin in potato tubers prestored at 15 ℃ was 24.50% and 8.24% higher than that at 4 and 25 ℃, respectively (P < 0.05). In addition, pre-storage at 15 ℃ significantly increased the contents of H2O2 and superoxide anion and peroxidase (POD) activity in periderm tissue. The findings suggested that postharvest pre-storage at 15 ℃ can accelerate the wound healing of potato minitubers grown in an aeroponic system through activating phenylpropane and reactive oxygen species metabolism in periderm tissue, and increasing the accumulation of SPP and SPA and the degree of suberization.
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The aim of this study was to evaluate the effect of exogenous abscisic acid treatment on periderm suberification of postharvest potato mini-tuber from aeroponic system, and to further explore its mechanism.
The original seed potato mini-tubers of Tongshu No. 1, free of artificial damage, were pre-stored at 15℃ (RH86-88%) respectively in dark environment for wound healing after dipping in exogenous abscisic acid (ABA) for 10 min. The weight loss rate of tuber during wound healing was measured, the accumulation of suberin and cork in pericardium cells was observed, and the phenylpropane and reactive oxygen metabolism in pericardium tissue of potato tuber were also analyzed.
25 mg∙L-1 ABA treatment and prestorage at 15℃ significantly reduced weight loss rate of microtuber, accelerated the accumulation of suberin and corkification in perituber tissue. Further studies showed that the key enzyme activities of phenylpropane metabolism and the content of total phenols, flavonoids and lignin of tuber tissues were significantly increased after ABA treatment, the enzyme activities of phenylalnine ammonia-lyase (PAL), 4-coumarate coenzyme A ligase (4CL), cinnamic acid 4-hydroxylase (C4H) and cinnamyl alcohol dehydrogenase (CAD) were significantly increased by 79.02%, 3.21%, 12.99% and 11.54%, respectively, compared with that of the control 21 days after storage. At the same time, ABA treatment decreased cell membrane permeability and malondialdehyde content, and increased
Postharvest ABA treatment could promote the accumulation of suberin and corkification in perituber tissue by activating the metabolism of phenylpropanoid and reactive oxygen species in periderm tissue, and accelerated the postharvest suberification process of aeroponic cultivated micro-potato tubers.
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