冬枣果实硬核期对^(15)N-尿素吸收、分配及再利用特性研究

Absorption and distribution of nitrogen from ^(15)N labelled urea applied at core-hardening stage in winter jujube.

以盆栽冬枣为试材,研究了冬枣果实硬核期土施15N-尿素条件下N的吸收、分配和再利用特性.结果表明,果实膨大期,细根中的肥料氮比率(Ndff%)最高为10.64%,其次为新生营养器官.果实采收后,叶片和枣吊中的15N回撤;翌年萌芽前,粗根中的Ndff%最高(3.69%);盛花期,新生营养器官(当年生枣头枝、枣吊、叶片和花)中的Ndff%最高.果实硬核期施肥后,当年根系吸收的15N-尿素主要用于营养生长(叶片、枣吊、根系),回撤15N优先贮藏于根系,休眠季节根系(54.01%)贮藏15N略高于地上部器官(45.99%),主要的15N贮藏器官为粗根(38.61%).地上部枝干中的贮藏15N从采果后到萌芽前含量变化剧烈,可作为贮藏15N营养诊断的“靶器官”,同期粗根中贮藏15N变幅较小,属长期“库”.贮藏15N具有就近利用的特性,其分配随生长中心的转移而转移.

The study with pot experiment showed that at the rapid-swelling stage of winter jujube fruit, the percent of nitrogen derived from fertilizer （Ndff % ） was the highest （ 10.64 % ） in fine roots, followed by new-growth nutritire organs,The absorbed urea-^15N decreased in leaves and deciduous supers, and accumulated preferentially in root systems after harvest. The Ndff% in coarse roots was the highest （3.69 % ） before budding stage, while that in new-growth organs （new branches, deciduous supers, leaves and flowers） was the highest at full-blooming stage. The urea-^15N applied at core-hardening stage mainly allocated in nutritive organs （leaves, deciduous supers, roots） in the first year, with the distribution rate 54.01% in root systems in winter, which was higher than that in branches （45.99 % ）. The ^15N stored in main branches changed drastically from post-harvest to budding stage. Main branches could be regarded as the ＇target organs＇ of N storage, while coarse roots were the ＇long term sink＇ of N storage. The N reserve distributed preferentially in contiguity organs, and the distribution center changed with the growth and development of winter jujube in next spring.