TReSpire - a biophysical TRee Stem respiration model.
TReSpire - a biophysical TRee Stem respiration model.
复制标题
TReSpire - 生物物理 TRee Stem 呼吸模型。
作者：
R. Salomón;Linus De Roo;J. Oleksyn;D. D. De Pauw;K. Steppe
植物呼吸的机制模型仍然不完善，特别是在茎和木本组织中，对二氧化碳外排的测量不一定反映局部呼吸活动。我们建立了一个基于过程的茎呼吸模型，该模型在器官水平上将水和碳通量结合在一起。为此，在枫树中测量了树液流、茎直径变化、木质部和土壤水势、茎温度、茎二氧化碳外排和非结构性碳水化合物，同时在辅助树中监测了木质部二氧化碳浓度和额外的茎和木质部直径变化，以验证模型。TReSpire现实地描述了：(1)膨胀压力以区分生长代谢和非生长代谢；(2)基于阿伦尼乌斯动力学和氮含量的木质部和外组织维持支出；(2)径向CO2扩散率和CO2在树液中的溶解度和输运。韧皮部卸载速率和糖-淀粉相互转化的共线性问题建议平行子模型来关闭茎碳平衡。TReSpire在详细（每小时）时间分辨率的茎水和碳通量建模方面取得了突破。TReSpire是从汇驱动的角度进行校准的，有可能促进我们对不同物种和物候阶段的茎生长动力学、二氧化碳通量和潜在呼吸生理的理解。这篇文章受版权保护。版权所有。
Mechanistic models of plant respiration remain poorly developed, especially in stems and woody tissues where measurements of CO2 efflux do not necessarily reflect local respiratory activity. We built a process-based model of stem respiration that couples water and carbon fluxes at the organ level (TReSpire). To this end, sap flow, stem diameter variations, xylem and soil water potential, stem temperature, stem CO2 efflux, and nonstructural carbohydrates were measured in a maple tree, while xylem CO2 concentration and additional stem and xylem diameter variations were monitored in an ancillary tree for model validation. TReSpire realistically described: (1) turgor pressure to differentiate growing from non-growing metabolism; (2) maintenance expenditures in xylem and outer tissues based on Arrhenius kinetics and nitrogen content; and (2) radial CO2 diffusivity and CO2 solubility and transport in the sap solution. Collinearity issues with phloem unloading rates and sugar-starch interconversion suggest parallel sub-modelling to close the stem carbon balance. TReSpire brings a breakthrough in the modelling of stem water and carbon fluxes at a detailed (hourly) temporal resolution. TReSpire is calibrated from a sink-driven perspective, and has potential to advance our understanding on stem growth dynamics, CO2 fluxes and underlying respiratory physiology across different species and phenological stages. This article is protected by copyright. All rights reserved.