苹果树体氮含量与氮累积量的年周期变化

以"富士"苹果树为试材,对树体生物量及不同器官氮含量和氮累积量的变化规律进行了研究。结果表明,3月26日至4月30日,树体和树冠的生物量变化较小,4月30日以后迅速增加;3月26日至7月30日,根系生物量几乎没有变化,7月30日以后快速增加。果树新生器官(果实、叶片和新梢)中氮含量均表现为物候期前期较高,中后期较低;成龄器官(枝、干、根系)中氮含量呈"V"字变化。3月26日到4月30日,器官建造时树体氮累积量逐渐增加;4月30日到7月30日,树体氮累积量稳定变化;7月30日至1月15日,树体氮累积量明显增加。年周期内不同时期各器官中氮累积量差异较大,树冠氮累积量始终高于根系。

Annual change of nitrogen content and accumulation in apple tree

"Fuji" apple trees were as the materials.Biomass,nitrogen content and accumulation in different parts of apple trees were studied in this paper.The results showed that biomass of tree and tree crown changed slowly from Mar 26 to Apr 30;and increased quickly after Apr 30.But biomass of roots system had no change from Mar 26 to Jul 30,and increased quickly after Jul 30.Nitrogen content in new organs(fruits,leaves and shoots) during early spring was higher than that in other time.The curve of nitrogen content in old organs(branch,trunk and root) assumed "V".From Mar 26 to Apr 30,nitrogen accumulation of tree increased slowly,kept stabilization during Apr 30 to Jul 30,and increased clearly after Jul 30.Nitrogen accumulation in different organs of apple tree changed largely in different time.And nitrogen accumulation in tree crown was higher than that in roots system any time.