水培环境下的作物养分吸收多参数检测系统研究

Study on Multi-parameter Detection System of Plant Nutrient Uptake Under Hydroponic Environment

在水培环境下对植物根系养分吸收的动力学主要利用耗竭曲线和系列含量法进行研究,而依靠人工间隔性的采样过程不但耗费人力而且影响效率。为解决这一问题,利用离子选择电极和图像传感器分别测定植物根系在水培环境下养分吸收时的离子含量和根系表面积,结合Michaelis-Menten方程获得植物动力学特征参数;系统硬件以STM32F407ZGT6微处理器作为主控单元,给出具有精密电化学传感器接口的信号调理与数据采集电路;在上位机系统中完成数据通讯、校准以及建模处理等。经测试表明,溶液校准后不同价态离子的能斯特斜率转换率分别在80%或90%以上;该系统与WinRHIZO获得的根系表面积相比,2组数据的线性相关性为0.97。该系统能够稳定的获取植株全根系的吸收临界浓度(Cmin)、最大吸收速率(Imax)、米氏常数(Km)等特征多参数,可为农作物营养的科学研究及水培环境下的养分吸收监测提供技术支撑。

The kinetics of nutrient uptaking by plant roots under hydroponic environment has been studied mainly by conventional depletion curve and series concentration methods,and because of relying on a manual interval sampling process,it is not only labor-intensive but also affects the efficiency.To solve this problem,the ion concentration and phenotype area of plant roots during nutrient uptake in hydroponic environment were measured using ion selective electrode and image sensor,respectively.Michaelis-Menten equation was combined to obtain plant kinetic characteristics parameter.The system hardware took STM32F407ZGT6 microprocessor as the main control unit,and signal conditioning and data acquisition circuit with precision electrochemical sensor interface was given.The data communication,calibration and modeling processing were done in the upper computer system.The experimental results showed that the energy-strength slope conversion rates of different valence ions after solution calibration were above 80%or 90%,respectively.The linear correlation between the root phenotypic area by proposed system and WinRHIZO root analysis software was 0.97.The system obtained the characteristic parameters such as the critical concentration of uptake(Cmin),the maximum uptake rate(Imax),and the Michaelis constant(Km)of the whole root system of the plant stably,which could be used for scientific research on crop nutrition and nutrient uptake under hydroponic environment technical support for monitoring.