基于白刺个体大小的生态化学计量模型

生态化学计量的提出为认识C、N、P耦合循环特征、驱动力及机制等提供了新方法,但植物在生长过程中的生态化学计量变化尚缺乏相关报道。本研究以唐古特白刺为对象,通过对白刺分株2017年当年生枝、2年生枝、大于2年生枝、叶、根和压条生物量及营养元素的测定,拟合了基于构件大小的元素总量,并推导了白刺各构件及整株依赖于个体大小的生态化学计量模型。结果表明: 推导模型能够反映植物在生长过程中的生态化学计量动态,老枝和压条均具有较高的N∶P与C∶P,叶、当年生枝和根均具有较低的N∶P与C∶P,白刺整株3种元素含量在生长过程中的累积速率为P>N>C。本研究结果符合现有的生长速率假说和异速生长理论,同时也可从侧面印证养分重吸收现象,该方法可作为分析植物生长过程中元素计量动态特征的一种有效途径。

An ecological stoichiometry model based on the size of Nitraria tangutorum

Ecological stoichiometry provides a new method for understanding the characteristics, driving forces and mechanisms of C, N and P coupled cycles. However, there are few reports on the variation in ecological stoichiometry of plants during their growth. In this study, we fitted the total elemental mass of different module based on the size of Nitraria tangutorum, and derived the ecological stoichiometry models of different module and whole ramet by measuring the biomass and nutrient concentrations of the current-year stems in 2017, 2-year-old stems, more than 2-year-old stems, leaves, roots and layerings of N. tangutorum ramet. Our results showed that the derivation model could well reflect the changes in ecological stoichiometry during plant growth. The old stems and the layering had higher N:P and C:P, while leaves,current-year stems, and roots had lower N:P and C:P. The whole plant nutrient elements cumulative rate was P>N>C during the growth process. These results were consistent with the growth rate hypothesis and allometric theory, and provide evidence for nutrient reabsorption. This model could be used as an effective way to analyze the dynamic characteristics of elements in plant growth.