油菜（Brassica napus L.）种子脱水耐性获得过程中肌醇半乳糖苷合成酶活性与可溶性糖含量的变化

在这个研究中测量不同发育时期的油菜种子中可溶性糖含量与肌醇半乳糖苷合成酶（galactinol synthase,GOLS）活性,将二者的变化趋势与种子脱水耐性获得的过程相比较并对结果进行相关性分析。结果显示油菜种子脱水耐性获得过程中,葡萄糖和果糖含量均随着发育期的延长而下降,蔗糖则保持较高水平;肌醇含量下降而肌醇半乳糖苷含量上升;棉子糖系列寡糖（raffinose familyolig osaccharides,RFO）含量随着种子发育而上升,特别是水苏糖,在成熟种子中可以达到相当高的浓度。油菜种子发育中期,细胞内GOLS活性开始上升,至贮藏物积累完成时达到最大。GOLS活性变化与种子肌醇半乳糖苷积累速度、RFO含量及种子的脱水耐性呈一定的正相关关系。我们认为GOLS促使RFO积累,从而对种子脱水耐性的获得产生重要影响。

Galactinol Synthase Activity and Soluble Carbohydrate Contents during Acquisition of Seed Desiccation Tolerance in Brassica napus L.

In this research, soluble carbohydrates concentrations and galactinol synthase activity in rapeseeds of different developing stages were determined. Their changing trends were also compared with the acquisition of seed desiccation tolerance. During development, concentrations of glucose and fructose declined, while sucrose content was always in a relatively high level. Inositol concentration decreased and galactinol concentration increased as seed development progressed. Raffinose family oligosaccharides （RFOs） levels in seeds were elevated during development, especially stachyose. Activity of galactinol synthase in seeds began to rise at middle stage of development and peaked when the reserve accumulation finished. Activity of galactinol synthase, accumulation of galactinol, concentration of RFO and acquisition of desiccation tolerance were all positively associated in developing seeds. We propose that galactinol synthase promotes the synthesis and accumulation of RFO, and thus deeply affected the acquisition of desiccation tolerance ofBrassica napus seeds.