采用盆栽实验，以0 mg·kg^-1硒酸钠为对照组，比较不同质量分数外源硒（5、10、15、20、25、30、35、40和45 mg·kg^-1硒酸钠）处理下核桃（Juglans regia Linn.）幼苗的生长和生理指标的差异，并对生长指标和生理指标间的相关性进行了分析。结果显示：与对照组相比，不同质量分数硒酸钠处理组核桃幼苗地径增长量总体显著升高，根尖数总体显著降低；苗高增长量、叶片数增长量、茎分枝数增长量、总叶面积、总根长、总根表面积、总根体积和根分叉数总体降低，但大部分处理组间无显著差异；茎鲜质量、茎干质量、根鲜质量和根干质量无显著变化。与对照组相比，10~20以及40 mg·kg^-1硒酸钠处理组核桃幼苗叶片超氧化物歧化酶（SOD）活性显著升高，5~15以及40和45 mg·kg^-1硒酸钠处理组的过氧化氢酶（CAT）活性显著升高，5、30和35 mg·kg^-1硒酸钠处理组的丙二醛（MDA）含量显著升高，15 mg·kg^-1硒酸钠处理的可溶性还原糖含量显著升高，10、20和45 mg·kg^-1硒酸钠处理组的可溶性蛋白质含量显著升高。相关性分析结果显示：核桃幼苗少数生长指标间的相关性达显著水平，其中，根分叉数与总根长、总根表面积、总根体积和根尖数呈极显著正相关，根鲜质量与总根长、总根表面积、总根体积、根尖数和根分叉数呈极显著正相关；生理指标间仅叶片超氧化物歧化酶活性与丙二醛含量呈显著负相关。综合研究结果显示：核桃幼苗生长和生理指标对不同质量分数外源硒的响应存在差异，外源硒对核桃幼苗地径有显著促进作用，对根尖数有显著抑制作用，对苗高增长量、叶片数增长量、茎分枝数增长量、总叶面积、总根长、总根表面积、总根体积和根分叉数有一定抑制作用，对茎和根质量无显著影响；适宜施用量的硒酸钠可显著提高幼苗叶片SOD和CAT活性以及可溶性还原糖和可溶性蛋白质含量。在开发富硒核桃产品时应根据实际需求施用硒肥。

  Taking 0 mg·kg^-1 sodium selenate as the control group, the differences in growth and physiological indexes of Juglans regia Linn. seedlings treated with different mass fractions of exogenous selenium (5, 10, 15, 20, 25, 30, 35, 40, and 45 mg·kg^-1 sodium selenate) were compared by using a pot experiment, and the correlations among growth indexes and physiological indexes were analyzed. The results show that compared with the control group, the ground diameter increment of J. regia seedlings in treatment groups of different mass fractions of sodium selenate significantly increase in general, while the number of root tip significantly decreases in general; the seedling height increment, leaf number increment, stem branching number increment, total leaf area, total root length, total root surface area, total root volume, and number of root bifurcation decrease in general, but there are no significant differences between most of the treatment groups; there are no significant variations in stem fresh mass, stem dry mass, root fresh mass, and root dry mass. Compared with the control group, the superoxide dismutase (SOD) activity in leaves of J. regia seedlings of 10-20 and 40 mg·kg^-1 sodium selenate treatment groups significantly increase, the catalase (CAT) activity of 5-15, 40, and 45 mg·kg^-1 sodium selenate treatment groups significantly increase, the malondialdehyde (MDA) content of 5, 30, and 35 mg·kg^-1 sodium selenate treatment groups significantly increase, the soluble reducing sugar content of 15 mg·kg^-1 sodium selenate treatment group significantly increases, and the soluble protein content of 10, 20, and 45 mg·kg^-1 sodium selenate treatment groups significantly increase. The correlation analysis result shows that there are significant correlations between a few growth indexes of J. regia seedlings, in which, the number of root bifurcation shows extremely significant positive correlations with total root length, total root surface area, total root volume, and number of root tip; the root fresh mass shows extremely significant positive correlations with total root length, total root surface area, total root volume, number of root tip, and number of root bifurcation; only SOD activity in leaves shows a significant negative correlation with MDA content between the physiological indexes. The comprehensive research result shows that there are differences in responses of growth and physiological indexes of J. regia seedlings to different mass fractions of exogenous selenium, and exogenous selenium has a significant promotion effect on ground diameter of J. regia seedlings, significant inhibitory effects on number of root tip, some inhibitory effects on seedling height increment, leaf number increment, stem branching number increment, total leaf area, total root length, total root surface area, total root volume, and number of root bifurcation, and no significant effect on stem and root masses of seedlings; suitable application amount of sodium selenate can significantly increase SOD and CAT activities in leaves of J. regia seedlings, as well as soluble reducing sugar and soluble protein contents. Selenium fertilizer should be applied according to actual needs when developing selenium-rich J. regia products.