‘紫柄籽银桂’桂花种子脱水耐性与抗氧化系统的关系

Changes on Physiological Characteristics of Osmanthus fragrans ‘Zibing Ziyingui’ Seeds During Dehydration

通过测定‘紫柄籽银桂’桂花种子在自然脱水过程中生理生化的变化,研究种子的脱水敏感性。结果表明:‘紫柄籽银桂’种子不耐脱水,种子生活力随着含水量的下降而降低,种子含水量下降到11.6%时,生活力仅为6%;自然脱水过程中,种子细胞膜系统受到损伤,相对电导率不断上升;种子内SOD活性随着含水量下降而呈总体下降的趋势;POD先波动上升,脱水12h时达到最大值,之后急剧下降。种子O2.-含量在脱水12h之前随含水量的下降而下降,12h之后随含水量的下降而急剧上升;随着脱水的进行细胞膜质过氧化程度加剧,MDA含量增加,导致种子丧失生活力。

The physiological characteristics changes of Osmanthus fragrans ＇Zibing Ziyingui＇ seeds during natural dehydration were measured to study the seed desiccation sensitivity. The results showed that O. fragrans seeds were desiccation-sensitive as the seed viability declined to 6% when the seed moisture content was reduced to 11.6%. The seed electrical conductivity increased with the declining moisture content, a sign, which was caused by increasing cell membrane cleavage. Superoxide dismutase （SOD） activity decreased rapidly during desiccation; But peroxidase （POD） activity increased to the maximal value when dehydration for 12 h, then declined rapidly when seeds were dehydrated more than 12 h. Superoxide anion radical content decreased with the declining moisture content, but it would increase rapidly when seeds were dehydrated more than 12 h. Malondialdehyde （MDA） content increased as seed moisture content declined, indicating that membrane peroxidation was accelerated and the seed viability would be lost.