【目的】探究增温促花后,施用氮磷钾复合肥对观赏海棠‘长寿冠’(Chaenomeles speciosa ‘Changshouguan’)生理特性的影响,为观赏海棠增温促花后的复壮栽培提供理论依据。【方法】以‘长寿冠’海棠5年生嫁接苗为材料,采用氮、磷、钾3因素的二次回归正交施肥试验设计,在‘长寿冠’海棠当年开花后2个月进行根部施肥试验,测定叶片可溶性糖、可溶性蛋白、内源激素含量及保护酶活性。【结果】①与对照相比,各氮磷钾复合肥处理下‘长寿冠’叶片可溶性糖和蛋白质含量均显著提高(P<0.05),以处理3(N₃P₃K₂)效果最佳,其叶片可溶性糖和蛋白质含量比对照分别增加40.60%和25.89%;②各配比氮磷钾复合施肥处理下,叶片过氧化物酶(POD)、超氧化物歧化酶(SOD)活性有不同程度的增加,丙二醛(MDA)含量降低,其中处理2(N₃P₂K₁)和处理3(N₃P₃K₂)效果较好,均与对照差异显著(P<0.05);③各配比氮磷钾复合施肥处理对‘长寿冠’内源激素脱落酸、生长素、赤霉素、玉米素(ABA、IAA、GA₃、ZR)含量均影响显著;适当的施肥处理提高了叶片IAA、GA₃、ZR含量,降低了ABA含量,处理组IAA、GA₃及ZR的总含量与ABA含量的比值均不同程度地提高。相关性分析表明,IAA、GA₃、ZR含量与叶片可溶性糖、蛋白质含量以及POD、SOD活性之间极显著正相关,而与MDA含量极显著负相关。ABA与叶片生理特性的相关性与其他激素相反;④方差分析表明,氮是肥料3因素中影响‘长寿冠’叶片生理特性的首要因素;多重比对分析表明,氮素水平对‘长寿冠’各项生理指标均产生显著影响,磷和钾对各指标显著性影响有所不同;隶属函数综合分析表明,改善‘长寿冠’叶片生理功能的最佳氮磷钾肥配施方案为N₃P₃K₂处理,即每株施氮肥1.2 g、磷肥0.3 g、钾肥0.4 g。【结论】施用适宜的氮磷钾复合肥能有效改善增温促花后‘长寿冠’海棠叶片的营养功能,增强其抗氧化能力;配方施肥的调节作用或与植株内源激素的调控有关。

【Objective】 The physiological characteristics of Chaenomeles speciosa ‘Changshouguan’ were investigated under nitrogen, phosphorus and potassium (N, P and K) compound fertilization to provide a theoretical basis for its rejuvenation cultivation after warming and promotion of flowering. 【Method】 In this study, a quadratic regression orthogonal fertilization experiment design was adopted using five-year-old grafted seedlings of ‘Changshouguan’, along with N, P, K factors. The root fertilization experiment of ‘Changshouuan’ was performed two months after flowering in the same year, and soluble sugar and protein, endogenous hormone, and protective enzyme activities were determined in the plant leaves. 【Results】 (1) Compared with the control, the soluble sugar and protein concentrations in leaves under combined N, P and K fertilizer treatments increased significantly (P<0.05), and the concentrations in leaves under treatment 3 (N₃P₃K₂) were 40.60% and 25.89% higher than those in the control, respectively. (2) The POD and SOD activities in leaves increased, whereas the MDA content decreased when different proportions of N, P and K compound fertilization were applied. Treatments 2 and 3 (N₃P₂K₁ and N₃P₃K₂) were more effective than control (P<0.05). (3) The combined application of N, P and K fertilizer had a significant effect on the endogenous hormone concentrations (ABA, IAA, GA₃ and ZR) of ‘Changshouguan’. Although appropriate fertilization increased the contents of IAA, GA₃ and ZR in leaves, it decreased the ABA content. The ratio of total IAA, GA₃ and ZR contents to that of ABA in treatment groups increased by varying degrees. Correlation analysis revealed that the concentrations of IAA, GA₃ and ZR were correlated positively with those of soluble sugar and protein and the activities of POD and SOD in leaves, whereas negatively with those of MDA. The correlation between ABA and the physiological characteristics of leaves was opposite to that between ABA and other hormones. (4) Anova indicated that N was the most important factor affecting leaf physiological characteristics among the three fertilizer factors. Multiple comparative analyses exhibited that the N level had significant effects on all physiological indexes, while P and K had varyingly significant effects on them. Comprehensive analysis of subordinate function revealed that the best combination of N, P and K fertilizer for improving leaf physiological function was N₃P₃K₂ treatment, that is, 1.2 g N, 0.3 g P, and 0.4 g K per plant. 【Conclusion】 Appropriate N, P, K compound fertilization can effectively improve the nutritional function and the antioxidant capacity of ‘Changshouguan’ leaves after warming and flowering promotion, which may be related to the regulation of endogenous hormones.