Page 160 - 《广西植物》2026年第2期
P. 160

3 5 4                                  广  西  植  物                                         46 卷
                 Abstract: To investigate the effects of different nitrogen applications on the growth and leaf nutrient uptake of Ochroma
                 lagopus plantationsꎬ one ̄ and a ̄half ̄year ̄old O. lagopus trees were used as experimental materials. Five treatments set
                                    ̄2                   ̄2                  ̄2
                 up: 0 (N0)ꎬ 50 kghm urea (N1)ꎬ 100 kghm urea (N2)ꎬ 50 kghm slow ̄release nitrogen fertilizer (PCU1)ꎬ
                              ̄2
                 and 100 kghm slow ̄release nitrogen fertilizer (PCU2)ꎻ tree heightꎬ diameter at breast height (DBH)ꎬ and leaf
                 carbon (C)ꎬ nitrogen (N)ꎬ phosphorus (P)ꎬ chlorophyllꎬ and non ̄structural carbohydrates (NSC) contents were
                 measured. The results were as follows: (1) Compared with the N0 treatmentꎬ tree heightꎬ DBHꎬ chlorophyll aꎬ
                 chlorophyll bꎬ and chlorophyll (a+b) contents were significantly increased by 28.66%ꎬ 50.72%ꎬ 50.17%ꎬ 50.71%ꎬ and
                 50.25%ꎬ respectivelyꎬ under the N2 fertilization treatment (P<0.05). (2) Compared with the N0 treatmentꎬ leaf N
                 content significantly increased by 60.16% (P<0.05) under the N2 fertilization treatmentꎻ P content showed a decreasing
                 trend. Under the N0 treatmentꎬ leaf N/ P<14ꎬ indicating that O. lagopus growth was limited by N element. After nitrogen
                 additionꎬ N/ P > 14ꎬ indicating that nitrogen fertilization altered the N ̄element limitation on O. lagopus growth. (3)
                 Compared with the N0 treatmentꎬ leaf soluble sugar and NSC contents were significantly increased by 78.98% and
                 52.49%ꎬ respectivelyꎬ under the N2 fertilization treatment (P<0.05). (4) Under urea applicationꎬ the leaf soluble
                 sugar content showed significant positive correlations with N contentꎬ C/ Pꎬ and N/ Pꎬ and a significant negative
                 correlation with P contentꎻ under slow ̄release fertilizer applicationꎬ the leaf starch content showed a significant negative
                 correlation with P content and a significant positive correlation with N/ Pꎻ under nitrogen applicationꎬ the leaf soluble
                 sugar and starch contents showed significant positive correlations with N content and N/ P. (5) The phenotypic plasticity
                 indices for leaf Nꎬ N/ Pꎬ C/ Pꎬ soluble sugar contentꎬ and soluble sugar/ starch were all relatively high. The cumulative
                 variance contribution rates of principal component 1 ( PC1) and principal component 2 ( PC2) were 66. 3%. In
                 summaryꎬ nitrogen addition significantly promotes the growth of O. lagopus and leaf nutrient absorptionꎬ with the N2
                 fertilization treatment yielding the best resultsꎻ nitrogen addition alleviates the limiting effect of nitrogen on O. lagopus

                 growthꎻ O. lagopus promotes growth by increasing chlorophyll contentꎬ improving leaf utilization efficiency of nitrogen
                 and phosphorusꎬ and thereby altering the distribution of leaf soluble sugar and starch contents.
                 Key words: Ochroma lagopusꎬ nitrogen additionꎬ chlorophyllꎬ soluble sugarꎬ starchꎬ correlation



                施肥作为调控植物营养吸收与生长发育的关                            素ꎬ其供应水平直接影响叶绿素的生物合成过程ꎬ
            键措施ꎬ通过养分供应的精准干预ꎬ可影响植物对                             因此氮添加通常可促进植物叶片叶绿素含量的增
            土壤营养元素的吸收与利用ꎬ并为植物生长发育                              加ꎬ并提高叶片氮含量ꎬ这种生理响应进一步通过
            提供氮、磷等必需营养物质( 何相玉ꎬ2023)ꎮ 不同                        优化光系统结构、增强酶活性等途径调节植物光
            施肥处理对植物生长发育的调控效应具有显著的                              合性能ꎬ最终实现植物生长状况的有效改善ꎮ 近
            双向性特征:当施肥量处于适宜水平时ꎬ可有效促                             几年ꎬ我国对关于施肥的研究进展迅速ꎬ在树木生
            进植物营养代谢与光合生理过程ꎬ表现为植株生                              长、养分动态和生理特征等方面均有长足发展ꎮ
            长健壮、枝叶繁茂ꎻ然而ꎬ过量施肥则易引发植物                             如何合理施用肥料ꎬ既能提高森林生产力ꎬ又能提
            碳氮代谢失衡ꎬ导致碳同化产物积累不足ꎬ进而造                             高肥料利用率ꎬ还能保障生态环境的可持续发展
            成茎秆机械组织发育滞后ꎬ抗倒伏能力降低且伴                              是林木施肥研究的一个重要方向ꎮ
            随病虫害易发生等负面效应(Wang et al.ꎬ 2019)ꎮ                       叶片作为植物光合作用的核心功能器官ꎬ其
            在林木生态系统中ꎬ氮素作为主要限制性营养因                              形态特征通过直接决定光合有效面积与光能截获
            子ꎬ对林木生长发育有显著的促进作用ꎬ尤其对速                             效率ꎬ成为影响植物光合生产力的关键结构性因

            生树 种 的 生 长 促 进 效 应 更 为 显 著 ( 文 程 敬 等ꎬ              素ꎬ而叶绿素作为光合作用中光能吸收、传递与转
            2025)ꎮ 贾瑞丰等(2012)研究表明ꎬ氮添加可通过                       化的核心色素ꎬ其含量不仅是衡量植物光能转化
            增强植物羧化效率与光能捕获能力ꎬ显著提升植                              效率的关键生理指标ꎬ更能敏感反映植物的营养
            株的株高生长量、胸径增量及生物量累积速率ꎻ同                             吸收状态与整体生长活力ꎬ是植物生理代谢水平
            时ꎬJi 等(2015)认为ꎬ氮添加对植物光合生理具有                        的直观表征( 陈梦秋等ꎬ2023ꎻ杨涛等ꎬ2023)ꎮ 在
            显著调控作用ꎬ氮作为叶绿素分子的核心组成元                              植物生理代谢的宏观框架中ꎬ碳( C)、氮( N)、磷
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