Partitioning and Modeling of Biomass in Caatinga Legume Seedlings in Different Water Conditions

ABSTRACT The accumulation of dry biomass, its partitioning and the adjustment of equations were assessed for the initial growth of Piptadenia stipulacea (Benth) Ducke and Anadenanthera colubrina (Vell.) Brenan under water availability variation. The experiment was conducted in pots arranged in a completely randomized design with three replicates. Water conditions were evaluated using the percentages of reference evapotranspiration. Samples of the biomass were taken at 10-day intervals and used for the achievement of partitioning data and model adjustments. The short period of water scarcity in the initial growth phase of P. stipulacea and A. colubrina does not affect the establishment of these species, but different water regimes alter their root growth dynamics. The A. colubrina allocates more dry matter to the roots, while P. stipulacea sends more dry matter to the aerial part. The Gaussian, Lorentzian, Log-Normal and Gompertz models had excellent adjustments for the biomass variables of the P. stipulacea species, whereas for A. colubrina, we recommend the Exponential model.

摘要：本研究针对水分可利用性变化条件下，柄荚腺蕊木（Piptadenia stipulacea (Benth) Ducke）与阔荚合欢（Anadenanthera colubrina (Vell.) Brenan）的初始生长过程，对其干生物量积累、生物量分配及方程拟合效果展开评估。本试验采用完全随机设计，以盆栽方式开展并设置3次重复。水分条件以参考作物蒸散量百分比进行量化表征。每10天采集一次生物量样品，用于获取生物量分配数据并开展模型拟合。柄荚腺蕊木与阔荚合欢初始生长阶段的短期缺水并不会影响其种群建植，但不同水分处理会改变二者的根系生长动态。阔荚合欢会将更多干物质分配至根系，而柄荚腺蕊木则将更多干物质分配至地上部分。高斯（Gaussian）模型、洛伦兹（Lorentzian）模型、对数正态（Log-Normal）模型及冈珀茨（Gompertz）模型对柄荚腺蕊木的生物量变量均具有极佳的拟合效果；而对于阔荚合欢，本研究推荐使用指数（Exponential）模型。