甘薯块根贮藏期间细胞壁成分及降解酶活性变化

Changes of cell wall components and degradation enzyme activity in sweetpotato storage roots during storage

为探明甘薯块根贮藏过程中细胞壁成分及酶活性与腐烂率的关系,以‘苏薯8号’、‘南薯88’和‘浙薯13’3个品种为材料,放置在温度为12℃,RH为85%的保鲜库中,贮藏期为102d,在0、7、15、30、45、60、81和102d分别取样,测定其细胞壁成分及酶活性。结果表明:3个品种甘薯块根贮藏期间可溶性果胶含量上升,原果胶含量下降,耐贮性好的‘苏薯8号’在贮藏当天有较高的纤维素含量66.53mg/g和木质素含量26.8mg/g,且木质素含量在贮藏期间变化波动小;贮藏45d,耐贮性差的‘南薯88’开始腐烂时,纤维素酶和半纤维素酶活性达到高峰值,分别是5 209.02和18 486.91μg/(g·h),β-半乳糖苷酶活性升高,贮藏102d,活性显著高于‘苏薯8号’2.5倍。相关性分析表明,腐烂率与失重率和β-半乳糖苷酶活性呈极显著正相关,与木质素含量呈极显著负相关,与纤维素酶活性呈显著正相关。耐贮性好的‘苏薯8号’甘薯块根中,木质素含量较高,半纤维素酶和纤维素酶活性较低,贮藏中后期β-半乳糖苷酶活性低且稳定。

To investigate the relationship between cell wall components,enzyme activity and decay rate during sweetpotato storage roots storage.The storage roots of’Sushu 8’,’Nanshu 88’and ’Zheshu 13’were used as materials and stored in a fresh-keeping storehouse at 12℃and a 85%humidity for 102 days.The cell wall components and enzyme activity were measured with samples taken at 0,7,15,30,45,60,81 and 102 d,respectively.The results showed that the soluble pectin content increased and the propectin content decreased during the storage period in the three varieties of sweetpotato storage roots.The content of cellulose(66.53 mg/g)and lignin(26.8 mg/g)of’Sushu 8’with good storage resistance were higher on the storage day,and the lignin content fluctuated little during the storage period.When the ’Nanshu 88’of poor storage resistance began to rot,the activity of cellulase and hemicellulase reached peak values,which were respectively 5 209.02 and 18 486.91μg/(g·h).Furthermore,when’Nanshu 88’was stored for 102 days,the activity ofβ-galactosidase was 2.5 times higher than that of’Sushu 8’.Correlation analysis results showed that the decay rate was significantly positively correlated withβ-galactosidase and weight loss rate,negatively correlated with lignin and positively correlated with cellulase.In conclusion,’Sushu 8’with good storage resistance has high lignin content,low hemicellulase and cellulase activity,and low and stable β-galactosidase activity in the middle and later stage of storage.