根区土壤氧气检测技术与方法研究进展

根区氧胁迫问题在滞涝区域、城市地面硬化区域尤为常见，根区土壤氧气含量高低是判断植物是否承受低氧胁迫的重要依据，其检测技术与分析方法的研究对农林生产和生态保护具有指导意义。为明确根区土壤氧气检测现状及发展方向，该研究概括了国内外土壤氧气分布检测方法和分析策略，将现有获取根区土壤氧含量时空分布的技术手段归纳为氧传感器点位检测法、土壤氧扩散模型分析法和荧光成像法，并剖析比较了各方法的优缺点和适用场景。基于氧传感器等领域最新进展，结合各类氧气运输模型，总结了根区土壤氧气分布检测技术和建模方法的研究重点与发展方向如下：1）氧传感器呈现小型化和集成化趋势，引入新型材料，提高氧传感器的灵敏度和耐久性能；2）模型的精度将不断提高，更多地考虑多尺度和多因素交互作用，以全面分析根区土壤氧环境的复杂性；3）开发可持续的荧光染料，提高荧光成像技术的分辨率和深度，以实现对更小、更深层次结构的清晰成像；4）分析植物蒸腾作用中的水氧关系，通过茎干氧浓度反映植物对根区氧环境变化的生理适应能力。研究可为植物根区土壤氧气分布检测提供思路与借鉴。

Advances in oxygen detection technologies and methods for the root zone soil

Continuous and stable oxygen supply is very necessary for plant tissues to maintain their normal metabolism. The evaluation of oxygen environment in the root zone can also serve to assess whether or not trees and plants are experiencing hypoxic stress. Research on detection and analysis technology is of great significance for the development of agroforestry and the environmental conservation. This study aims to summary the detection and analysis strategies of soil oxygen distribution. The current technologies were also reviewed to obtain the spatial and temporal distribution of soil oxygen in the root zone, such as the fluorescence imaging, the oxygen sensor point detection, and the soil oxygen diffusion analysis. The future directions were clarified on the root zone soil oxygen detection. The buried oxygen sensor was utilized to monitor the oxygen environment in the soil. Three categories of detection were divided: the zirconia, the electrochemical approach, and the fiber optic sensing. It is difficult to capture the oxygen content of the entire root zone, leading to disrupt the structure of the soil and then cause harm to the root system of the plant. However, the high level of accuracy was obtained for the detection of oxygen concentrations and time resolution. It is possible to acquire the soil oxygen concentration gradient in a short amount of time by modelling soil oxygen diffusion. According to the physical and chemical features of the soil, the gradient can also be obtained to estimate the soil oxygen environment where the plant roots are located. The structure and parameters of the model were closely connected to the chemical and physical characteristics of the soil. It is very necessary to modify the model suitable for the specific situation using the reliable input data from the soil sampling spots. The fluorescence in-situ imaging approach can be used to acquire the real-time distribution of the oxygen concentration in the soil rhizosphere. The non-invasive monitoring can also be employed to uncover the interactions that occur between organisms and the environment in the similar natural conditions. The procedure can be carried out in a laboratory setting to predict the field. The latest advances were compared under the different applicable scenarios in the field of oxygen sensors combined with various types of oxygen transport models. The hot topics and development directions were finally summarized on the detection techniques and models of soil oxygen distribution in the root zone: 1) Oxygen sensors can be the promising trend of miniaturization and integration, and the new types of materials can also be introduced to improve the sensitivity and durability of the oxygen sensors; 2) The accuracy of the models can be continuously improved to consider the multi-scale and multi-factor interactions under the complex soil oxygen environment in the root zone; 3) Sustainable fluorescent dyes can be developed to improve the resolution and depth of fluorescence imaging for the clear imaging of smaller and deeper structures; 4) The water-oxygen relationship can be further analyzed in the plant transpiration. The physiological adaptive capacity of plants can be used to reflect the oxygen environment in the root zone using the oxygen concentration in the xylem. The finding can provide a strong reference for the soil oxygen environment in the root zone of plants.