果梅幼树对春施^(15)N-硫铵的吸收与分配

Studies on the Absorption and Distribution of 15N-labelled Ammonium Calcium Applied to Prunus mume Trees in Spring

以盆栽3年生细叶青梅/毛桃为试材,研究了早春施用^(15)N-(NH_4)_2SO_4条件下,果梅对^(15)N的吸收分配规律。结果表明:由于春季土温较低,限制了植株对肥料氮的利用率。在新梢旺长期,植株从肥料氮中吸收的氮素营养主要用于新生器官的建造,且新梢成为^(15)N的主要分配中心,其次即为果实,再其次为细根。至花芽分化期,植株的生长中心已发生转移和分散,但春施氮对促进当年生枝的花芽分化和维持叶片正常光合功能仍有重要作用,此期亦是根系生长的关键时期之一,且与贮氮相比,春施氮更有利于当年新根的萌发和根系的扩大。

Three-year-old trees of Prunus mume /Primus persica were fertilized with 15N-labelled ammonium calcium via soil in early spring for studying the absorption and distribution. The results showed the utilization ratio of N fertilizer was quite low due to low soil temperature. During shoot rapid-growing period, much more N was mobilized to new shoots, fruit and rootlets; the NDFF was higher in new shoots than in fruit, and in fruit higher than in rootlets. Later on the growing center in tree transferred and decentralized. N application in early spring promoted flower-bud differentiation on current branches and preserved leaves in normal physiological action. The flower-bud differentiation stage was one of the crux stages of new root development. N application in spring was more advantage to root-growth and root-expanding than storage N.