Organic acids in apple trees and their effects on zinc uptake and distribution under zinc deficiency

【目的】研究缺锌大田富士苹果树、苹果幼树和苹果树常用砧木平邑甜茶[Malus hupehensis (Pamp.) Rehd.]幼苗有机酸与锌吸收分配的关系,探讨有机酸影响锌吸收分配的作用机理。【方法】采用盛果期苹果树大田栽培、两年生幼树砂培和平邑甜茶幼苗溶液培养法进行试验。【结果】萌芽期小叶病树根系R0-1.5、R1.5-3、R3-5和R5-15锌和有机酸浓度呈现高于正常树的趋势,盛花期二者的浓度呈现低于正常树的趋势,生理落果期小叶病树根系R0-1.5、R1.5-3、R3-5和R5-15锌浓度显著大于正常树。与正常树相比,有机酸浓度小叶病树R0-1.5和R1.5-3中下降,R3-5和R5-15呈现升高的趋势,小叶病树根系锌吸收利用和有机酸代谢运输节奏发生改变,大田和水培试验发现,苹果树根系有机酸的水平与锌水平有关。缺锌导致盆栽幼树吸收根有机酸含量的升高。与pZn2+ 10.7相比,水培平邑甜茶pZn2+ 11.3处理1 d,根中锌浓度显著下降,根和茎中草酸和苹果酸的浓度升高了1.09―1.35倍,有机酸向根系的分配比例增加,根系锌吸收速率显著增加;处理20 d,平邑甜茶植株中的锌浓度和有机酸浓度及叶中有机酸的分配比例均显著下降。【结论】缺锌改变了苹果根系锌吸收和有机酸的代谢运输节奏,促进了有机酸向地下部的分配,有机酸在促进锌吸收分配方面起重要作用。 【Objective】 To explore the functional mechanism of the effect of organic acids on Zn uptake and distribution, organic acids in apple cultivar ‘Fuji’ in the field, two-year old ‘Fuji’ and rootstock Malus hupehensis (Pamp.) Rehd. seedlings were detected, and their effects on Zn uptake and distribution under Zn deficiency was studied. 【Method】 ‘Fuji’ was sampled at bud, florescence and physiological fruit dropping stages in the field, two