14C-寡糖在西瓜幼苗植株体内吸收传导和分布

应用同位素示踪技术研究了14C-寡糖在西瓜幼苗植株体内的吸收、传导和分布行为.自显影结果显示,寡糖通过处理叶部或根部后能够被西瓜幼苗植株快速吸收,在叶片中的传导表现为从叶缘向叶片中心分布的趋势.将叶部处理8h和根部处理24h后,14C-寡糖即可以传导和分布到西瓜幼苗的整个植株体内,证明14C-寡糖在西瓜幼苗植株体内具有较强的扩散和向基或向顶传导特征.结果表明,处理叶部4～120h时,根系、茎与未被直接处理的叶片等其它部位的放射性比活度分别由0.18×105和23.08×105Bq/kg变化为0.32×105和3.02×105Bq/kg,总体上表现出向基传导和分布的态势.处理根部4～120h时,西瓜幼苗植株根系、茎部、子叶和真叶中放射性比活度分别由22.23×105,2.23×105,8.33×105和12.78×105Bq/kg变化为431.11×105,42.23×105,65.57×105和78.89×105Bq/kg,表现出14C-寡糖在西瓜幼苗植株体内向顶传导作用和在地上部的积累态势很强.

Uptake, Translocation and Distribution of 14C-Labelled Oligosaccharides in Watermelon Seedling

Uptake, translocation, and distribution of 14C-labelled oligosaccharides in watermelon seedling were investigated by the means of radioactive isotope tracer. The autoradiograph experiment showed that oligosaccharides could fast be absorbed by the watermelon seedling after it was supplied through leaf or root. The translocation of the oligosaccharides in leaf trended from the margin to the center. After treatment by leaf-dripping for 8 h and treatment by root-dipping for 24 h, the oligosaccharides translocated and distributed in whole watermelon seedling, indicating that 14C-labelled oligosaccharides have a strong ability to spread and translocate downwards or upwards in the seedling. During 4 h to 120 h after the treatment by leaf-dripping, the specific activity of root, others(stem and indirectly treated leaf in the whole seedling) transformed from 0.18×105 and 23.08×105 Bq/kg to 0.32×105 and 3.02×105 Bq/kg, respectively. As a whole, the trend of distribution and downward translocation was weak. During 4 h to 120 h after the treatment by root-dipping, the specific activity of root, stem, cotyledon, and true leaf transformed from22.23×105, 2.23×105, 8.33×105 and 12.78×105 Bq/kg to 431.11×105, 42.23×105, 65.57×105 and 78.89×105 Bq/kg, respectively, suggesting a strong accumulation trend above the ground and upward translocation activity of 14C-oligosaccharides in watermelon seedling.