关键词: 苹果, 平邑甜茶, 有机酸, 锌, 吸收分配

Abstract:

【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-year old ‘Fuji’ in sand culture, Malus hupehensis (Pamp.) Rehd. seedlings were grown hydroponically and two treatments (pZn2+ 11.3, pZn2+ 10.7) were conducted for 1 d and 20 d before determination of organic acids. 【Result】 In R0-1.5, R1.5-3, R3-5 and R5-15, Zn and organic acids concentrations were mostly significantly higher in rosette tree than that in normal tree at bud stage while mostly lower at florescence stage, however, at physiological fruit dropping stage, Zn concentration of root was higher in rosette tree than that in normal tree, organic acids concentrations decreased in R0-1.5 and R1.5-3 while mostly increased in R3-5 and R5-15 of rosette tree. The rhythm of Zn absorption and organic acid metabolism were changed, organic acid levels were highly related to the total Zn levels in root of ‘Fuji’ in field and of hydroponical Malus hupehensis (Pamp.) Rehd. The organic acids concentrations in absorbing roots of two-year old ‘Fuji’ rose under Zn deficiency. The hydroponical Malus hupehensis (Pamp.) Rehd experiment showed that compared with pZn2+ 10.7, pZn2+ 11.3 treatment for 1 d, Zn concentration in root decreased significantly, while oxalic acid and malic acid concentrations in stem and root increased by 1.09-1.35 fold, the distribution proportion of root organic acid elevated, Zn uptake rate significantly increased. While treatment for 20 d, Zn and organic acids concentrations, organic acid distribution proportion of leaf significantly decreased.【Conclusion】 The rhythm of Zn absorption and utilization and organic acid metabolism and transportation were changed by Zn deficiency, which promoted organic acids transport from shoot to root. Organic acids play an important role in promoting Zn uptake and distribution.

Key words: apple, Malus hupehensis (Pamp.) Rehd, organic acid, Zn deficiency, uptake and distribution