库尔勒香梨春季施用15N-尿素的吸收、分配和利用特性

以6年生库尔勒香梨为试材,在春季香梨萌芽前施用¹⁵N尿素,研究香梨施用¹⁵N尿素的吸收、分配和利用特性.结果表明:不同生育期香梨吸收的¹⁵N在各器官的分配率存在显著差异,盛花期¹⁵N优先分配在根中,其Ndff(从肥料中吸收的¹⁵N量对该器官全氮量的贡献率)最高,新稍次之;新梢旺长期和果实膨大期根部吸收的¹⁵N优先向新生器官(叶和新稍)运转,根部¹⁵N的分配率不断下降;果实成熟期果实成为新的分配中心,其Ndff最高,果实累积的¹⁵N量占香梨树体总的¹⁵N吸收量的19.8%.香梨树体对土施¹⁵N-尿素肥料的当季利用率随生育期的推进而不断提高,到果实成熟期达到最大值(18.5%).

Characteristics of absorption,utilization, and distribution of 15N-urea for Korla fragrant pear in spring.

Six-year-old Korla fragrant pear trees were fertilized with ¹⁵N-labelled urea before early bud stage to examine the absorption, distribution, and utilization of urea. Results showed that there was a significant difference of ¹⁵N distribution rate in organs at different growth stages. ¹⁵N was pre-ferentially distributed in the roots , with Ndff (¹⁵N amount absorbed from the fertilizer contribution rate of the total nitrogen organ) being the highest in roots following by new shoots at full-bloom stage. During new shoot growing and fruit expanding stages, ¹⁵N absorbed in roots preferentially moved to new organs (leaves and new shoots), with ¹⁵N distribution rate to roots being continuously decreased. Fruits became the new distribution center with highest Ndff at harvest stage. The amounts of absorbed ¹⁵N in fruits accounted for 19.8% of total absorbed ¹⁵N in the tree. The utilization rate of ¹⁵N-labelled urea at current season increased gradually with the growth stages. The maximum value of utilization rate was 18.5%, which was observed at harvest stage.