The technical feasibility of bio-fixation of extra CO₂ into plants was investigated in this study using biogas slurry as CO₂ carrier and lettuce as the model plant. CO₂ was absorbed into 5-times-concentrated-biogas-slurry (5-CBS) to act as the hydroponic solution for lettuce cultivation while chemical nutrient solution was tested as a control. Effects of these solutions on lettuce cultivation performance such as lettuce growth and nutrient absorption were compared. Also, mechanisms of CO₂ bio-fixation from biogas slurry into the lettuce was explored by exposing lettuces to different drought stress. Results showed that CO₂-rich 5-CBS can cultivate the lettuce for achieving similar growth performance (main-root length, plant height, stem diameter and biomass) to the chemical nutrient solution, confirming its low phytotoxicity to lettuce. CO₂ introduction in form of HCO₃⁻ into biogas slurry can enhance N, P and K absorption performance of the lettuce, which is 42.53 %, 167.87 % and 18.03 % higher than that of chemical nutrient solution, respectively. Furthermore, CO₂ in form of HCO₃⁻ from the hydroponic solution was mainly fixed into the lettuce stem through being involved in the lettuce epidermal photosynthesis. HCO₃⁻ can be decomposed to generate water for compensating the internal water deficient environment and CO₂ for protecting the photosynthetic system of lettuce from injury caused by the drought stress. Due to the utilization of HCO₃⁻, the whole carbon utilization rate of lettuce can be maintained about 14.13 μmol−HCO₃⁻/(m²·s) under the drought stress, which is higher than the photosynthetic rate for the case without the drought stress.

本研究以沼液为CO ₂载体，以生菜为模型植物，研究了将多余的CO ₂生物固定在植物上的技术可行性。将CO ₂吸收到5倍浓度沼气浆液（5-CBS）中，作为莴苣栽培的水培溶液，同时测试化学营养液作为对照。比较了这些溶液对莴苣栽培性能如莴苣生长和养分吸收的影响。此外，通过使生菜暴露于不同的干旱胁迫下，探索了从沼液到生菜中的CO ₂生物固定机制。结果表明，CO ₂富含5-CBS的莴苣可以种植以达到与化学营养液相似的生长性能（主根长度，植物高度，茎直径和生物量），从而证明其对莴苣的低植物毒性。CO ₂引入HCO的形式₃ ^-成沼气浆料可提高生菜，这是42.53％，167.87％和18.03％比化学营养液的更高，分别为N，P和K的吸收性能。此外，CO ₂在HCO的形式₃ ^-从水培溶液中主要是通过被卷入莴苣表皮光合作用固定在莴苣干。HCO ₃ ^-可以分解产生的水来补偿内部缺水的环境，并分解CO ₂来保护生菜的光合系统免受干旱胁迫的伤害。由于HCO的利用率₃ ^- ，莴苣的整个碳利用率可以被保持在约14.13微摩尔-HCO ₃ ^- /（米² ·秒）的干旱胁迫，这比没有的情况下的光合速率更高下干旱压力。