Ríos-Rojas Liliana, Tapia Franco, Gurovich Luis A
Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Chile.
Universidad de Santiago de Chile, Chile.
J Plant Physiol. 2014 Jun 15;171(10):799-806. doi: 10.1016/j.jplph.2014.02.005. Epub 2014 Mar 4.
Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a continuous signal with daily maximum and a minimum EP of similar magnitude in time, with zero slope. This plant electrical behavior is proposed for the development of a sensor measuring real-time plant water status.
本文介绍了一种基于结果木本植物电生理行为的实时植物水分胁迫传感器的开发与评估。在不同灌溉方案下，对树干中的连续电位进行测量，从而诱导出不同的水分胁迫条件；结合传统传感器连续测定的土壤含水量和微大气蒸发需求，对结果进行讨论，并将这些信息与树木电位测量结果相关联。给出了两种果树水分胁迫和非胁迫树木电位的系统且可区分的模式。利用这些电生理传感器还可以监测水分胁迫条件的早期检测和恢复动态，从而实现全年高效灌溉调度的连续无损测量。该实验在温室区域的法拉第笼中，在可控条件下对鳄梨和李子植株进行。使用电容传感器控制土壤湿度变化，通过位于实验场地的微型农业气象自动站中的精确气象传感器，连续记录太阳辐射、温度、相对湿度、风速和风向。电生理传感器有两个不锈钢电极（测量电极/参考电极）插入茎中；使用高精度吉时利2701数字万用表测量植物电信号；用MatLab(®)编写的算法可将信号与环境变量相关联。在实验植株中观察到电循环行为（昼夜周期）。对于未灌溉的植株，电信号呈现出一个随时间上升的斜率，然后在整个较长的恢复过程中，重新开始灌溉后出现负斜率，直至达到斜率为零的稳定电信号。浇水良好的植株呈现出一个连续信号，每日最大值和最小值的电势能在时间上幅度相似，斜率为零。这种植物电行为被用于开发一种测量实时植物水分状况的传感器。
