子瓜果实贮存期细胞壁超显微结构及相关成分的变化

以大板黑瓜子子瓜为材料,西农8号西瓜为对照,测定和观察不同贮藏期果实硬度、果皮、果肉细胞壁超显微结构、中果皮果胶及其相关酶的变化,研究子瓜果实耐贮性机理。结果表明,贮藏前期子瓜果实硬度较大、中果皮原果胶含量呈上升趋势,25d后平缓下降,西农8号西瓜中果皮果胶酶(PE)、多聚半乳糖醛酸酶(PG)活性在贮藏期存在明显的高峰,子瓜相应酶的活性变化趋势平缓,果皮果肉组织相关细胞结构解离,破坏时期与程度早于、重于子瓜,至实验结束时,已基本丧失其原有的结构,而子瓜还维持一定程度的完整性。由此认为,子瓜贮存期原果胶含量较高,PE、PG活性变化平缓,细胞壁和细胞膜系统超显微结构相对稳定可能与耐贮性有关。

Changes in cell wall ultra-structure and components of seed-used watermelon fruit in storage

Fruit of seed-used watermelon cultivars Dabanhiezi and watermelon cultivar Xinong 8# were used as materials to study changes of fruit firmness, cell wall ultra-structure, pectin content and activity of pectin-degrading enzyme of middle fruit skin in storage. The results showed that the fruit firmness was relatively high at early storage, propectin content went up before 25 days, then dropped gently; changes of pectinmethy lesterase (PE) and polygalacturonase (PG) activity were gentle in seed-used watermelon cultivar; Propectin content was lower, cell wall, cell membrane et al of watermelon cultivar Xinong 8# were decomposed more seriously and earlier than that of seed-used watermelon cultivar. There was a peak in the changes of PE and PG activity of watermelon cultivar. Thus it can be considered that the higher propectin content, gentle changes of PE and PG activity, relatively stable cell wall and cell membrane ultra-structure probably related with longer storage time of seed-used watermelon fruit.