Abstract The effectiveness of post-harvest foliar-applied Fe(II)-sulfate was assessed and indices were tested for precocious prognosis of Fe-chlorosis in field-grown pear trees. In a commercial pear (Abbé Fétel/BA 29) orchard, Fe-induced chlorotic trees were sprayed in early autumn with a Fe(II)-sulfate heptahydrate solution and compared with water-sprayed control trees. Leaf Fe concentration was higher in senescent and abscised leaves of Fe-sprayed trees, indicating that Fe was taken up. However, phytotoxic symptoms occurred and leaves fell earlier than in untreated trees. Fe(II)-sulfate spray increased Fe concentration of flower buds and fruiting spur leaves as well as leaf Chl values. Yield was increased in sprayed trees by about 13%, mostly associated with a higher fruit number per tree rather than fruit size, indicating an improved fruit set. We hypothesize that a fraction of the absorbed Fe contributed to sustain Fe requirements of the newly formed organs as from growth resumption. Summer leaf SPAD readings were positively correlated with Fe concentration of flower buds, fruiting spur leaves and, in particular, with senescent and abscised leaves. Our findings suggest the effectiveness of the post-harvest foliarly applied Fe(II)-sulfate to improve Fe nutrition of pear trees the following season. Rather than inducing a temporary re-greening, our approach is based on the fact that high Fe-rates sprayed before leaf fall may contribute to increase Fe pools within perennial organs. We propose utilizing leaf Fe concentration of senesced and abscised leaves as a predictive tool for the diagnosis of the Fe-chlorosis occurrence in pear trees.

中文翻译：

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收获后叶面喷施 Fe(II)-硫酸盐促进钙质土壤中梨树的铁营养

摘要 评价了收获后叶面喷施硫酸铁（II）的有效性，并测试了对田间梨树中铁萎黄病早熟预后的指标。在商业梨 (Abbé Fétel/BA 29) 果园中，早秋用 Fe(II)-硫酸盐七水合物溶液喷洒 Fe 诱导的褪绿树木，并与喷水的对照树木进行比较。喷铁树的衰老和脱落叶片中的Fe浓度较高，表明Fe被吸收。然而，发生了植物毒性症状，叶子比未经处理的树木更早掉落。Fe(II)-硫酸盐喷雾增加了花芽和结果刺叶的Fe浓度以及叶Chl值。喷洒树木的产量增加了约 13%，主要与每棵树的果实数量增加而不是果实大小有关，表明坐果得到改善。我们假设从生长恢复开始，一部分吸收的 Fe 有助于维持新形成的器官对 Fe 的需求。夏季叶片 SPAD 读数与花蕾、结果刺叶，特别是衰老和脱落叶片的 Fe 浓度呈正相关。我们的研究结果表明，收获后叶面喷施硫酸铁 (II) 可有效改善下一季梨树的铁营养。我们的方法不是诱导暂时的重新绿化，而是基于这样一个事实，即在落叶前喷洒高铁率可能有助于增加多年生器官内的铁库。我们建议利用衰老和脱落叶片的叶 Fe 浓度作为诊断梨树中 Fe 萎黄病发生的预测工具。