水稻种子耐干性机理的研究

STUDY ON MECHANISM OF DESICCATION TOLERANCE OF RICE SEEDS

以籼稻C38、粳稻京21、杂交稻秋优3为材料,进行种子超干储藏特性的研究,进而探讨种子耐干性的机理。通过超干水稻种子生活力和活力的比较,发现籼稻C38耐干性较强。超干有利于保持种子抗氧化酶系统的完整性,因此超干能提高种子的耐储性。对超干种子可溶性糖含量与组分进行分析,结果表明随着种子含水量的降低,蔗糖含量增高,多糖和葡萄糖含量降低,籼稻C38的蔗糖含量明显低于粳稻京21和杂交稻秋优3。用热重仪测定的种子含水量与烘干法得到的数据相吻合,用差示热量扫描仪测定束缚水/自由水的比例和玻璃化转变温度Tg,发现籼稻C38的Tg高于粳稻京21和杂交稻秋优3,籼稻C38束缚水/自由水比例大于粳稻京21和杂交稻秋优3,而束缚水/自由水的比例与耐干性成正相关。由此表明,耐干性在不同的水稻品种间有明显的差异,籼稻C38的耐干性较强。

We selected rice seeds of Indica rice （C38）, Japonica rice （Jing21）, hybrid rice （Qiuyou3） as material for research of seed ultradry storage and further discovered mechanism of seed desiccation tolerance. By comparing viability and vigor of ultradry rice seed, thus we found Indica rice （C38） had better desiccation tolerance. Ultradryness can help maintain integrity of antioxidase systems, so as to improve storability of rice seeds. The analysis of content and sorts of soluble sugar demonstrated that sucrose content was increased, amylase and glucose was decreased along with reduction of moisture content, furthermore, the sucrose content of Indica rice （C38） was obviously less than Japonica rice （Jing21） and hybrid rice （Qiuyou3）. Seed moisture content determine by temperature gravity instrument in accord with that by drying method. The proportion of bind/free water and converse temperature of vitrification（Tg） were determined by differential scanning calorimetry（DSC）, the result showed the Tg and proportion of bind/free water of Indica rice （C38） were more than Japonica rice （Jing21） and hybrid rice （Qiuyou3）. Moreover, the proportion of bind/free water with desiccation tolerance had a positive correlation. The final results showed that desiccation tolerance had obvious difference in different rice varieties and Indica rice （C38） had better desiccation tolerance.