西瓜种子内源β-半乳甘露聚糖酶活性与分布以及与萌发速度的关系

Activity and distribution of endo-β-mannanase during germination of watermelon seeds and its relationship with germination rate

利用单粒种子凝胶扩散法研究了β-半乳甘露聚糖酶在西瓜种子萌发过程中的分布以及与西瓜种子萌发速率的关系。结果发现,在胚根尖突破种皮前吸胀的西瓜种子中,内源β-半乳甘露聚糖酶主要分布于种子的胚膜套中,并起到减弱外种皮和胚膜套细胞壁对胚根伸出的机械阻力的作用。对具有不同萌发速率的品种以及引发处理和未处理的西瓜种子中酶活性的检测证明,β-半乳甘露聚糖酶活性与西瓜种子萌发速度相关。固体基质引发三倍体西瓜种子过程中β-半乳甘露聚糖酶的活化和种皮阻力的减弱,是引发种子提高了萌发速度和萌发能力的原因之一。

Activity and distribution of endo-β-mannanase during germination of watermelon seeds was measured and the relationship with germination rate were investigated by using single-seed gel-diffusion. The results show that endo-β-mannanase activity is mostly distributed in perisperm-endosplerm（PE）envelope during seed imbibing prior to radicle emergence and play an important role in weakening cell wall of PE envelope and testa and lower their mechanical resistance for radicle emergence. The investigation with two varieties of watermelon seeds which are in different germination rate and capacity as well as primed and unprimed seeds indicate that there＇s a positive correlation between watermelon seed germination rate and endo-β-mannanase activity. PE envelope weakening and endo-β-mannanase activity are initiated during priming of triploid watermelon seeds is one of the reasons of enhancement of germination rate and germination capacity for primed seeds.