【目的】探究不同时期喷施不同浓度磷酸二氢钾(KH₂PO₄)对娜塔栎(Quercus texana)叶片呈色的影响,阐明磷、钾元素与叶色变化的关系,为娜塔栎在长江流域的景观应用提供理论依据与技术支撑。【方法】以6年生娜塔栎实生苗为试材,在不同时期对其叶面喷施不同浓度的KH₂PO₄溶液。采用色差仪测定叶片L^*、a^*、b^*色差空间参数(CIE),计算明亮度(ΔL^*)、红度值(Δa^*)、黄度值(Δb^*);同步测定叶绿素、花色素苷及可溶性糖含量,综合分析生理指标与叶色的关联性。【结果】① 8月30日喷施0.4% KH₂PO₄处理的叶片娜塔栎叶片ΔL^*(明亮度)提升最高;8月30日喷施0.6% KH₂PO₄处理的叶片Δb^*(黄度)增加最高;9月15日喷施0.4%KH₂PO₄处理的叶片Δa^*(红度)增幅最大。② 随生育期推进,叶绿素含量持续下降,花色素苷含量及花色素苷含量与叶绿素含量比值(K值)整体上升,可溶性糖含量呈先升后降趋势。③ 指标相关性分析表明:b^*值与L^*值呈显著正相关(P<0.05),a^*值与花色素苷含量呈显著正相关(P<0.05),花色素苷含量与叶绿素含量呈负相关,花色素苷/叶绿素比值与叶绿素含量呈显著负相关(P<0.05),花色素苷含量与可溶性糖含量呈极显著正相关(P<0.01)。④ 主成分分析提取2个主成分,累计贡献率79.8%,其中PC1贡献率52.6%。基于隶属函数法综合评价显示,9月15日喷施0.8% KH₂PO₄处理的综合效果最优(D值最高)。【结论】通过生理指标与叶色参数的关联分析,确定9月15日叶面喷施0.8% KH₂PO₄为最佳处理方案,可显著提升娜塔栎秋季叶色表现。

【Objective】The study aims to explore the effects of spraying potassium dihydrogen phosphate (KH₂PO₄) at different concentrations and periods on the leaf color of Quercus texana. The relationship between phosphorus and potassium nutrition and leaf color change is elucidated, thereby providing a theoretical basis and technical support for the landscape application of Q. texana in the Yangtze River Basin.【Method】Six-year-old seedlings of Q. texana were sprayed with different concentrations of potassium dihydrogen phosphate solution at different growth stages. The CIE L^*, a^* and b^* color space parameters of leaves were measured using a colorimeter, and the brightness difference (ΔL^*), red-green difference (Δa^*), and yellow-blue difference (Δb^*) were then calculated. Concurrently, the contents of chlorophyll, anthocyanin and soluble sugar were determined. Finally, the correlations between physiological indexes and leaf color was comprehensively analyzed.【Result】(1) The ΔL^* (brightness) increase was maximized by spraying 0.4% KH₂PO₄ on August 30, and the Δb^* (yellowness) increase was maximized by spraying 0.6% KH₂PO₄ on August 30, whereas the Δa^* (redness) enhancement was maximized by spraying 0.4% KH₂PO₄ on September 15.(2) As the growth period progressed, a decline in chlorophyll content was observed, accompanied by an increase in anthocyanin content and the anthocyanin/chlorophyll ratio (K value). The soluble sugar content initially increased and then decreased. (3) The researchers found signifficantly positively correlated between the b^* value and the L^* value (P<0.05), as well as a significant positive correlation between the a^* value and the anthocyanin content (P<0.05). In addition, a negative correlation was observed between anthocyanin and chlorophyll (P<0.05), and a significant positive correlation was observed between anthocyanin and soluble sugar content (P<0.01). (4)Principal component analysis (PCA) extracted two principal components, with a cumulative contribution rate of 79.8%, of which the first component (PC1) contributed 52.6%. The comprehensive evaluation, based on the membership function method, showed that the comprehensive effect of spraying 0.8% KH₂PO₄ on September 15 was the best (with the highest D value).【Conclusion】Through the correlation analysis of physiological indexes and leaf color parameters, it was determined that the optimum treatment scheme for significanlty improve the leaf color performance of Q. texana in autumn was through the application of 0.8% KH₂PO₄ on September 15.