【目的】通过研究典型黑土区水土保持树种生态化学计量特征,明确其养分利用特征及其生理适应策略。【方法】从物质分配角度,以典型黑土区常用的水土保持树种小叶锦鸡儿(Caragana microphylla)、榆叶梅(Prunus triloba)、白桦(Betula platyphylla)、糖槭(Acer saccharinum)、红皮云杉(Picea koraiensis)和樟子松(Pinus sylvestris var. mongholica)为研究对象,包括常绿乔木、落叶灌木和落叶乔木3种生活型,测定其叶、皮、枝、干、细根和粗根的碳、氮、磷质量分数[分别以c(C)、c(N)、c(P)表示],分析碳氮磷化学计量比及其异速生长关系。【结果】总体来看,碳的稳定性大于氮和磷,且落叶树种地下部分碳稳定性大于地上部分;氮的稳定性在3种生活型中均表现为地上大于地下;磷则在灌木的叶片中有最大的变异系数。c(C)表现为地上总量大于地下总量,氮、磷具有一致的分配策略,均表现为细根中含量大于粗根中含量。相关性分析表明,乔木树种的c(C)与c(N)呈正相关,与c(P)的相关性不显著;灌木树种的c(C)与c(N)呈极显著负相关,与c(P)呈显著负相关。C-N和C-P在不同器官间具有显著异速生长关系,C的积累速度大部分表现为小于N和P的积累速度;而N-P在器官间的异速生长关系差异明显,常绿乔木除皮和细根外表现为等速生长,落叶灌木的叶呈等速生长,落叶乔木的6种器官间均呈等速生长关系,且N的积累速度均小于P,落叶灌木的干和粗根以及落叶乔木的N积累速度接近于P的积累速度。【结论】植物各器官对养分元素的吸收利用具有一定的协同性,且联系紧密,可以通过研究元素之间的耦合效应来研究植物的适应策略,但限制性元素N和P的生理代谢过程在不同生活型幼苗间存在差异,因其物种本身特性差异的影响,会形成不同的营养元素分配模式及化学计量比特征。本研究结果可为水土保持植物的科学培育和典型黑土区的水土保持林营造提供理论依据。

【Objective】This study aimed to clarify the nutrient-use characteristics and physiological adaptation strategies of six commonly used soil and water conservation tree species in a typical black soil region.【Method】From the perspective of biomass allocation, six species were selected: Caragana microphylla, Prunus triloba, Betula platyphylla, Acer saccharinum, Picea koraiensis, and Pinus sylvestris var. mongholica, representing three life forms (evergreen arbors, deciduous shrubs, and deciduous trees). Mass fractions of carbon (C), nitrogen (N), and phosphorus (P) were measured in leaves, bark, branches, stems, fine roots, and coarse roots. Stoichiometric ratios (C/N, C/P, N/P) were calculated, and correlation analyses and allometric models were applied to examine relationships among element concentrations and their accumulation rates across organs.【Result】Carbon mass fractions exhibited greater stability than N and P; for deciduous species, belowground carbon stability exceeded that of aboveground parts. Nitrogen stability was consistently higher aboveground than belowground across all life forms, while the coefficient of variation for P was highest in shrub leaves. Total C mass fraction was greater in aboveground than belowground organs, whereas both N and P followed the same allocation strategy, with fine-root concentrations exceeding those in coarse roots. In tree species, C and N concentrations were positively correlated (P < 0.05), while C-P correlations were not significant; in shrub species, C correlated very significantly negatively with N (P < 0.01) and significantly negatively with P (P < 0.05). Significant allometric relationships were found for C-N and C-P across organs, with C accumulation rates generally lower than those of N and P. In contrast, N-P allometries varied by life form: evergreen arbors showed isometric growth between N and P in all organs except bark and fine roots; deciduous shrubs exhibited isometry only in leaves; deciduous trees displayed isometric N-P relationships across all six organs, with N accumulation rates consistently lower than those of P, while in stems and coarse roots of deciduous shrubs and across organs of deciduous trees, N accumulation rates were close to those of P. 【Conclusion】Nutrient uptake and utilization across plant organs are coordinated and tightly coupled, but the physiological metabolism of limiting elements N and P differ among seedlings of different life forms. Species-specific traits give rise to distinct nutrient-allocation patterns and stoichiometric characteristics. These findings provide a theoretical basis for the scientific cultivation of soil and water conservation species and the establishment of conservation forests in the typical black soil region of China.