【作者】 李园园；

【导师】 金鹏；

【作者基本信息】 南京农业大学 ， 农业推广硕士（专业学位）， 2017， 硕士

【摘要】 本文以“红艳”草莓为试材,研究了 2,4-表油菜素内酯浸泡处理对草莓果实采后品质和抗病性的影响,从活性氧代谢、苯丙烷类代谢以及病程相关蛋白的角度探讨2,4-表油菜素内酯处理诱导草莓果实抗病机理,结果如下:1.探究了 2,4-表油菜素内酯浸泡处理抑制草莓果实腐烂的最佳浓度,发现5.0μmol/L 2,4-表油菜素内酯处理效果最佳,2.5 μmol/L和10 λmol/L 2,4-表油菜素内酯处理对抑制果实腐烂的作用都达不到最佳效果。通过分析不同浓度的2,4-表油菜素内酯处理对草莓果实的腐烂指数和腐烂率的显著性的影响,和测定草莓果实相关抗氧化物质含量,筛选出5.0μmol/L浓度的2,4-表油菜素内酯处理更适用于草莓果实保鲜。2.探究了 2,4-表油菜素内酯浸泡处理对采后草莓果实品质、膜脂质过氧化程度、活性氧相关酶活性和次生代谢产物的影响。结果表明5.0 μmol/L 2,4-表油菜素内酯处理能有效抑制草莓果实腐烂,一定程度地延缓了果实中TSS含量下降,降低了膜脂质过氧化程度,从而维持果实品质,延长贮藏期限。此外,5.0μmol/L2,4-表油菜素内酯处理还显著提高了果实中活性氧代谢相关酶活性,例如超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、抗坏血酸过氧化物酶(APX)的提高,使果实保持较高的总酚、花色苷、类黄酮含量,维持较高的抗氧化活性。3.探究了 2,4-表油菜素内酯处理诱导草莓果实抗病性的机理,发现5.0μmol/L 2,4-表油菜素内酯处理能通过调控果实中苯丙烷类代谢相关酶活性,例如苯丙氨酸解氨酶(PAL)、4-香豆酸CoA连接酶(4-CL)和肉桂酸羧化酶(C4H),诱导提高果实中的抗氧化物质含量。通过抑制果实中超氧阴离子产生速率来降低果实中MDA含量,减少膜脂过氧化程度。另外,在生物胁迫作用下利用5.0 μmol/L2,4-表油菜素内酯处理能显著提升几丁质酶(CHT)和β-1,3葡聚糖酶(GLU)的活性。结果表明,5.0 μmol/L 2,4-表油菜素内酯处理调控了采后草莓果实苯丙烷类代谢以及病程相关蛋白活性来延缓果实成熟衰老、抑制果实腐烂。更多还原

【Abstract】 Freshly harvested strawberry fruits ’HongYang’ were treated with 5.0 μmol/L 2,4-epibrassionolide.To investigate the effects and potential mechanism of 2,4-epibrassionolide on postharvest physiology and quality,and disease resistant ability of strawberry,the active oxygen metabolism,phenylpropanoid metabolism and induced disease resistance of fruits were analyzed.The results were as follows:1.We explored the effects of 2,4-epibrassionolide different treatment on decay of strawberry fruits,and found that the 2,4-epibrassionolide at 5.0 μmol/L could suppress the occurrence of strawberry fruit rot.When the concentration of 2,4-epibrassionolide was reached 2.5 μmol/L and 10 μmol/L,the inhibition effect was weakened.In addition,2,4-epibrassionolide concentration at 5.0 μmol/L could effectively maintain the antioxidant content.Compared to the decay and quality of strawberry fruit treated by different concentration,these results suggest that the 2,4-epibrassionolide at 5.0 pmol/L has a positive effect in preservation of strawberry.2.To investigate the effects of 2,4-epibrassionolide immersion on postharvest quality,the level of membrane peroxidation,the activity of antioxidant enzymes and the secondary metabolites of phenylpropanoid metabolism were analyzed.The results indicated that 2,4-epibrassionolide treatment at 5.0 μmol/L for 5 minutes significantly inhibited fruit decay,delayed the decreases of TSS,reduced membrane peroxidation and thus maintained fruit quality.Moreover,2,4-epibrassionolide treatment 5.0 μmol/L also effectively enhanced the activity of antioxidant enzymes,like superoxide dismutase,catalase and ascorbate peroxidase,induced the accumulation of total phenolic,anthocyanin and flavonoid,and kept high level of antioxidant activity.Therefore,our results suggested that 5.0 μmol/L 2,4-epibrassionolide treatment had a potential use for preserving postharvest quality and maintaining high antioxidant activity of strawberry fruit.3.We analyzed the effect of 2,4-epibrassionolide treatment in delaying ripening,senescence and disease-resistance of strawberries,and found that the 2,4-epibrassionolide treatment at 5.0 μmol/L could improve the activity of phenylpropanoid metabolism enzymes like PAL,4-CL and C4H in fruit,maintain the higher content of vitamine C,total phenol,total flavonoid and total anthocyanins.Inhibit the increase of O2·-content and the accumulation of MDA content.Besides,2,4-epibrassionolide treatment at 5.0 μmol/L effectively increased the activity of disease resistance related enzymes like GLU and CHT.These results suggest that 2,4-epibrassionolide treatment at 5.0 μmol/L can delay fruit senescence and inhibit fruit decay through maintaining the activity of phenylpropanoid metabolism related enzymes and enhancing disease resistance in postharvest strawberry fruit.更多还原