Currently, greenhouse soil has cadmium (Cd) pollution problems, causing serious Cd accumulation in various crops, including cucumber. Grafting is now widely used in greenhouse cucumber production, but the role and mechanism of grafting in regulating Cd accumulation and tolerance of cucumber merits further investigated. We used popular planted cucumber varieties ‘Jinchun No 4’ (Cj) and ‘Lvguan’ (Cl) as scions and the pumpkin varieties ‘Yemu Yixiong’ (Py) and ‘Jingangzuan F1’ (Pj), which are characterized by strong tolerance, weak absorption and low transport capacity of Cd, as rootstocks, to investigate the effect of grafting on Cd tolerance and accumulation in cucumber and its mechanism. Compared with self-rooted cucumber, cucumber grafted onto Py and Pj rootstocks exhibited significantly reduced Cd concentrations in scions and fruits, with improved biomass and fruit quality. There was a slight reduction in Cd concentrations in scions after self-grafting compared to self-rooted cucumber, and this reduction was more significant when Pj was the rootstock. Thus, the reduction effect of grafting was mainly dominated by rootstock effects. Grafting significantly increased the proportions of cell wall Cd, pectate- and protein-bound Cd (FNaCl), and undissolved phosphate-sequestrated Cd (FHAc) of cucumber, whereas it decreased the proportions of Cd in the soluble fractions and organelles as well as inorganic (FE) and water-soluble (FW) Cd. Therefore, grafting cucumber onto ‘Jingangzuan F1’ and ‘Yemu Yixiong’ alleviated Cd accumulation and improved Cd tolerance of cucumber by increasing compartmentalization of Cd in cell walls and promoting conversion of Cd to low-toxicity forms.

中文翻译：

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嫁接对黄瓜Cd耐受性和积累特性的影响


目前，温室土壤存在镉 （Cd） 污染问题，导致包括黄瓜在内的各种作物中 Cd 积累严重。嫁接目前在温室黄瓜生产中应用广泛，但嫁接在调节黄瓜 Cd 积累和耐受性中的作用和机制有待进一步研究。以广受欢迎的种植黄瓜品种'金春四号'（Cj）和'绿关'（Cl）为接穗，以耐镉性强、吸收弱、转运能力低的南瓜品种'野目益雄'（Py）和'金钢钻F1'（Pj）为砧木，研究嫁接对黄瓜镉耐受性和积累能力的影响及其机制。与自根黄瓜相比，嫁接到 Py 和 Pj 砧木上的黄瓜在接穗和果实中表现出显著降低的 Cd 浓度，生物量和果实品质得到改善。与自根黄瓜相比，自嫁接后接穗中 Cd 浓度略有降低，当 Pj 为砧木时，这种降低更为显着。因此，嫁接的减少效应主要由砧木效应主导。嫁接显著提高了黄瓜细胞壁 Cd、果胶酸盐和蛋白质结合的 Cd （FNaCl） 和未溶性磷酸盐螯合的 Cd （FHAc） 的比例，而降低了可溶性组分和细胞器以及无机 （FE） 和水溶性 （FW） Cd 的比例。因此，将黄瓜嫁接到'金港钻F1'和'野木益雄'上，通过增加Cd在细胞壁中的区室化，促进Cd转化为低毒形式，减轻了黄瓜的Cd积累，提高了黄瓜的Cd耐受性。