苦瓜果实不同发育时期细胞壁组分及相关酶活性的差异分析

Differences of Cell Wall Components and Related Enzyme Activities in Momordica charantia Fruits at Different Development Stages

摘要:

为了解苦瓜(Momordica charantia)果实品质差异的原因，以厚肉型种质‘LX1-3’和薄肉型种质‘ZK54’为材料，对果实发育过程中细胞壁组分含量及相关酶活性进行了分析。结果表明，花后17 d，‘LX1-3’果实的横径(FD)、腔径(FLD)、果肉厚度(PT)、单瓜鲜质量(FFW)和干质量(FDW)均超过‘ZK54’。细胞壁组分和酶活性表现品种间差异，水溶性果胶含量整体水平表现为厚肉型高于薄肉型，且与PT、FFW和FDW呈显著正相关；花后17~23 d ‘LX1-3’的半纤维素(HCE)和纤维素(CE)含量均高于‘ZK54’；花后3 d，两种质的β-半乳糖苷酶(β-Gal)和β-木糖苷酶(β-Xyl)活性显著高于其他3个时期，多聚半乳糖醛酸酶(PG)、β-Gal和果胶酶变化趋势与离子型果胶和共价型果胶含量的变化一致。β-Gal、β-Xyl和纤维素酶活性与5个生长性状间呈极显著/显著负相关，PG与FD、FLD和PT呈极显著/显著负相关。因此，细胞壁组分和酶活性与果实发育密切相关，β-Xyl和β-Gal在苦瓜早期发育中发挥主要效应，而HCE和CE对果实中后期发育影响较大。

Abstract:

In order to understand the causes of fruit quality differences in Momordica charantia, the contents of cell wall components and related enzyme activities in thick flesh-type ‘LX1-3’ and thin flesh-type ‘ZK54’ were studied during fruit development. The results showed that diameter (FD), lumen diameter (FLD)，pulp thickness (PT), fresh weight (FFW) and fresh weight (FDW) of fruit in ‘LX1-3’ were all higher than those in ‘ZK54’ at 17 days after flowering (DAF). The contents of cell wall components and related enzyme activities were different among cultivars. the content of water-soluble pectin in ‘LX1-3’ was higher than that of ‘ZK54’, and it was significantly positively correlated with PT, FFW, FDW. The contents of hemicellulose (HCE) and cellulose (CE) in ‘LX1-3’ were higher than those in ‘ZK54’ at 17-23 DAF. The activities of β-Gal and β-Xyl of both cultivars at 3 DAF were higher than those at the other three stages. The variation trend of PG, β-Gal and pectinase activities was consistent with that of ionic pectin and covalent pectin. The activities of β-Gal, β-Xyl and cellulase had (extremely) significantly negatively correlated with 5 growth traits, as well as PG with FD, FLD and PT. Therefore, cell wall components and enzyme activities were closely related to fruit development. β-Xyl and β-Gal played major roles in early fruit development, while HCE and CE had great influence on middle and later fruit developments.