顽拗性板栗种子成熟前后褐变与可溶性糖的关系

试图揭示板栗种子褐变与脱水敏感性和可溶性糖含量之间的关系。板栗种子成熟脱落时，脱水敏感性相对较弱，子叶和胚轴中棉籽糖和水苏糖含量达最高峰，电导率和紫外吸收值最低，总酚含量与POD活性较低。种子脱落后，脱水敏感性上升，子叶和胚轴中棉籽糖和水苏糖含量下降，膜渗漏物质增多，总酚含量及POD活性急剧上升，从而导致褐变发生。胚轴中总酚含量与POD活性存在显著的正相关(r=0.999)，而棉籽糖含量分别与POD活性和总酚含量存在显著的负相关(r分别为－0.998和－0.995)。结果表明，可溶性糖的组分及其含量可能与板栗种子脱水敏感性大小有关，板栗种子脱落后还原性糖麦芽糖含量的上升与褐变的发生趋势一致，而非还原性糖特别是棉籽糖可能在抑制褐变方面具有一定作用。

Relationship between browning and soluble sugar of recalcitrant seeds of chestnut in front of and behind maturation

This study aims to discover the relationship among browning, the contents of soluble sugars and desiccation sensitivity in chestnut seeds. When the seeds matured, the desiccation sensitivity of the seeds was low relatively, the contents of raffinose and stachyose in cotyledons and embryonic axes reached maximum and the relative electric conductivity and ultraviolet absorption value were lowest. The contents of total phenolics and the activity of POD were low in cotyledons and embryonic axes before abscission, then increased remarkably after abscission. After abscission the chestnut seeds were stored in sands. The desiccation sensitivity increased, the contents of raffinose and stachyose in cotyledons and embryonic axes declined, the leakage increased, and the contents of total phenolics and the activity of POD were sharply increased, flowed by browning. The contents of total phenolics were obviously positive correlated to POD activity (r=0.999) and the raffinose contents were obviously negative correlated to POD activity and total phenolics contents respectively (r=-0.998 and r=-0.995) in embryonic axes. The results indicated that the ingredients and the contents of soluble sugars were related to the desiccation sensitivity of chestnut seeds. After maturation, the increasing of the deoxidized sugars (maltose) contents consistent with the browning and the non-deoxidized sugars (raffinose) restrain the browning possibly.