采后外源脱落酸处理对雾培微型马铃薯周皮木栓化的影响及其机理

【目的】研究采后外源脱落酸处理对雾培微型马铃薯周皮木栓化的效果，并进一步探讨其促进木栓化的机理。【方法】以‘通薯1号’雾培马铃薯原原种为试材，在无损伤的条件下，用外源脱落酸(ABA)浸泡10 min，于15℃(RH 86%-88%)黑暗环境中预贮。测定贮藏期间块茎的失重率，观察块茎周皮细胞中软木脂和木质素的积累，分析块茎周皮组织苯丙烷和活性氧代谢的变化。【结果】采后25 mg·L^-1 ABA处理后15℃预贮能显著降低雾培微型马铃薯块茎的失重率，加速块茎周皮组织处软木脂和木质素的积累。ABA处理后块茎组织中苯丙代谢关键酶活性显著提高，总酚、类黄酮和木质素含量增加，在贮藏21 d时，处理块茎的苯丙氨酸解氨酶(phenylalnine ammonia-lyase,PAL)、4-香豆酸辅酶A连接酶(4-coumarate coenzyme A ligase,4CL)、肉桂酸-4-羟化酶(cinnamic acid 4-hydroxylase,C4H)和肉桂醇脱氢酶(cinnamyl alcohol dehydrogenase,CAD)活性分别较对照提高了79.02%、3....

Effects of Exogenous Abscisic Acid Treatment on Periderm Suberification of Postharvest Mini-Tuber Potato from Aeroponic System and Its Possible Mechanisms

【Objective】 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. 【Method】 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. 【Result】 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 $\mathrm{O}_2^{\bar{.}}$ and H₂O₂ content and enzyme activities of NADPH oxidase (NOX), super oxide dismutase (SOD), catalase (CAT) and peroxidase (POD), the enzyme activities of NOX, SOD, CAT and POD in treated tubers were increased by 47.33%, 8.61%, 27.27% and 14.50%, respectively, 21 days after storage. In addition, ABA treatment also activated antioxidant system AsA-GSH cycle and effectively maintained the intracellular redox balance. 【Conclusion】 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.