不同大小辽东栎种子的脱水敏感性

以采自宁夏六盘山区的辽东栎种子为材料,在缓慢脱水和快速脱水条件下,研究了不同大小种子的脱水耐性。结果表明,轻度脱水对种子萌发具有促进作用,但种子萌发率随着脱水时间的延长和含水量的继续减少而显著降低;不论是缓慢脱水还是快速脱水,不同大小种子的萌发速率和萌发指数均随脱水时间的延长持续减小或波动性减小,且都在缓慢脱水36h后和快速脱水8h后显著降低;活力指数在缓慢脱水72h和快速脱水24h前的各脱水阶段均不同程度地增大,但在缓慢脱水120h和快速脱水48h后显著减小。大种子含水量和萌发率在脱水过程中始终显著高于小种子;尽管不同大小种子间的萌发率仅在脱水后期差异显著,但大种子萌发速率、萌发指数和活力指数均显著大于小种子,且在脱水处理后期所有萌发参数在不同大小种子间均差异显著。

The Desiccation Sensitivity of Quercus wutaishanica Seeds of Different Size

Taking Quercus wutaishanica seeds collected from Liupan Mountain of Ningxia as test materials,experiments were conducted to investigate the desiccation sensitivity of seeds of different size to slow and rapid drying rate.The results showed that the germination of Q.wutaishanica seeds were accelerated by slight desiccation of both slow and rapid drying treatments,while the germination percentage significantly declined with the delay of drying time and the decreasing of moisture content of seeds.The germination rates and germination indices of both large and small seeds decreased continually or fluctuatly with the extending of drying period regardless of slow or rapid desiccation treatment.Moreover,both of them decreased significantly after slow drying for 36 h and rapid drying for 8 h.The vigor indices increased in various degrees in different drying periods before being treated by slow drying 72 h and rapid drying 24 h,but declined markedly after slow desiccation for 120 h and rapid desiccation for 48 h.The moisture contents and germination percentages of large seeds were always significantly higher than those of small seeds during both slow and rapid drying periods.In spite of the fact that significant difference of germination percentage between large and small seeds was detected only in late stages of desiccation,the germination rate,germination indices and vigor indices of large seeds all higher significantly than those of small seeds,and significant difference in all germination parameters were found between large and small seeds at the period of desiccation treatments.