Budding is an important grafting technique to asexually propagate pecan (Carya illinoinensis (Wangenh.) K. Koch). To determine factors that might hamper successful budding of the species, a representative easy-to-survive cultivar ‘Pawnee’ and a typical difficult-to-survive cultivar ‘Jinhua’ were used for comprehensive analysis. Morphological observation showed that cells surrounding the secretory cells or sieve tube had collapsed in ‘Jinhua’ but not in ‘Pawnee’ during grafting. ‘Jinhua’ might suffer more hypoxia stress than ‘Pawnee’ as ‘Jinhua’ had higher catalase, superoxide dismutase, polyphenol oxidase, pyruvate decarboxylase (PDC), alcohol dehydrogenase (ADH) activities during grafting and contained greater levels of hydrogen peroxide 12 days after grafting (DAG). Transcriptions of PDC and ADH were also up-regulated significantly in ‘Jinhua’ whereas they were not significantly affected in ‘Pawnee’. Phenylalanine ammonia-lyase activities of ‘Jinhua’ were consistently lower than that of ‘Pawnee’. Initial phenol contents were similar between the two cultivars. Graft-promoting substances, including soluble sugar, soluble protein, and gibberellin (GA) were incompletely recovered in ‘Jinhua’ 12 DAG while fully restored in ‘Pawnee’. Increased levels of trans-zeatin riboside in ‘Jinhua’ were much smaller than in ‘Pawnee’ 3 DAG. The contents of indole-3-acetic acid were similar, and the dynamics of abscisic acid were the same between the two genotypes. Results suggest that hypoxia stress and shortages of sugar, protein, GA, and cytokinin during the healing process might be key factors limiting successful budding of pecan. The degree of scion-rootstock compatibility and the content of phenols might be excluded as constraints for successful budding.

芽接是无性繁殖山核桃（ Carya illinoinensis (Wangenh.) K. Koch）的重要嫁接技术。为确定影响该品种出芽成功的因素，对代表性易存活品种“波尼”和典型难存活品种“金花”进行了综合分析。形态学观察显示，嫁接过程中‘金花’分泌细胞或筛管周围的细胞已塌陷，而‘波尼’则没有塌陷。'金花'可能比'波尼'遭受更多的缺氧应激，因为'金花'在嫁接过程中过氧化氢酶、超氧化物歧化酶、多酚氧化酶、丙酮酸脱羧酶（PDC）、乙醇脱氢酶（ADH）活性较高，并且嫁接后12天含有较高水平的过氧化氢嫁接（DAG）。PDC和ADH的转录在“金华”中也显着上调，而在“波尼”中则没有显着影响。‘金花’的苯丙氨酸解氨酶活性始终低于‘波尼’。两个品种的初始苯酚含量相似。“金花”12 DAG 中的可溶性糖、可溶性蛋白和赤霉素 (GA) 等促接枝物质未完全恢复，而“波尼”则完全恢复。‘Jinhua’中反式玉米素核苷水平的增加远小于‘Pawnee’3 DAG。两种基因型之间吲哚-3-乙酸的含量相似，脱落酸的动态也相同。结果表明，愈合过程中缺氧应激和糖、蛋白质、GA 和细胞分裂素的缺乏可能是限制山核桃成功发芽的关键因素。接穗与砧木的相容性程度和酚类物质的含量可能被排除在成功出芽的限制因素之外。