Abstract Quince (Cydonia oblonga Mill.) represents an examplar rootstock in modern training programmes to escalate pear production worldwide because of its dwarfing characteristic and precocity. However, iron deficiency often poses a hard hurdle to overcome for developing quince grafted pears in calcareous and alkaline soils. In North China, we observed that the high-quality pear cultivar Huangguan (Pynus bretschneideri Rehd.) grafted onto quince A (Hardy as interstock, defined as HG-QA) suffered iron deficiency chlorosis in calcareous soils in early spring, even more severe during late spring to early summer. In contrast, Huangguan grafted onto Pyrus betulifolia (Hardy as interstock, defined as HG-PB) did not suffer it. We were inspired to design this field experiment to figure out iron mobilization/uptake in the two rootstocks and the two scion-rootstock combinations. Our results showed that the soil plant analysis development (SPAD) values of quince A (24.7) and HG-QA (13.7) were much lower than that of Pyrus betulifolia (41.6) and HG-PB (36.1). The root length density and surface area density of quince A and HG-QA were more than 2-fold higher than those of Pyrus betulifolia and HG-PB. The rhizosphere pH of quince A and HG-QA was more than 0.20 units lower than that of Pyrus betulifolia and HG-PB respectively, whereas we didn’t detect any obvious differences in the root ferric-chelate reductase activity, iron concentrations in leaves and roots, and iron transport ratio. These results strongly suggest that the iron efficiency of HG-PB is attributed to an iron activation mechanism in leaves. The deciphering of the mechanisms that how rootstock influences the iron acquisition system inside the leaf of the scion and changes the efficiency of iron utilization will facilitate making effective solutions for iron deficiency induced chlorosis, popularizing and planting Huangguan grafted onto quince A in pear production.

中文翻译：

---

梨品种对比铁黄化耐受性分析。'黄冠'嫁接到钙质土壤中生长的桦木和木瓜A上

摘要 榅桲 (Cydonia oblonga Mill.) 因其矮化特性和早熟性而代表了现代培训计划中提高全球梨生产的示范砧木。然而，缺铁通常是在钙质和碱性土壤中开发木瓜嫁接梨的难以克服的障碍。在华北地区，我们观察到优质梨品种黄​​冠（Pynus bretschneideri Rehd.）嫁接在榅桲A（Hardy as interstock，定义为HG-QA）上早春钙质土壤缺铁性黄化，在春末夏初。相比之下，嫁接在桦木梨（Hardy as interstock，定义为HG-PB）上的黄冠没有受到影响。我们受到启发设计了这个田间试验，以找出两种砧木和两种接穗砧木组合中铁的动员/吸收。我们的结果表明，木瓜 A (24.7) 和 HG-QA (13.7) 的土壤植物分析发展 (SPAD) 值远低于 Pyrus betulifolia (41.6) 和 HG-PB (36.1)。榅桲 A 和 HG-QA 的根长密度和表面积密度比 Pyrus betulifolia 和 HG-PB 高 2 倍以上。榅桲 A 和 HG-QA 的根际 pH 值分别比 Pyrus betulifolia 和 HG-PB 低 0.20 个单位，而我们没有检测到根铁螯合还原酶活性、叶片中铁浓度和根和铁转运比。这些结果强烈表明 HG-PB 的铁效率归因于叶子中的铁激活机制。破解砧木如何影响接穗叶片内铁吸收系统并改变铁利用效率的机制，将有助于有效解决缺铁性缺绿问题，促进黄冠嫁接在梨生产中的推广和种植。