Plant Water Dynamics Sensor Using Resistance Probe for Xylem Positioning

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Solution Overview

Problem

Current water dynamics sensors are unable to accurately measure water movement in fine points of plants, such as the distal end of new branches, without causing damage, which is crucial for optimizing crop productivity and quality.

Innovation Solution

A plant water dynamics sensor with integrated electrical resistance and temperature probes that detect the xylem position, allowing for precise placement and minimizing plant damage, enabling high-accuracy measurement of water flow rates and directions without the need for drilling or cutting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If rod-shaped temperature sensors and heater-equipped sensors are arranged in holes formed in the trunk with a drill, then sap flow rate measurement is enabled, but the plant structure is damaged and epidermis is chipped off

Engineering Contradiction:
Improvesap flow rate measurementVSAvoidplant structure damage
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention extracts only the necessary sensing function from the traditional drill-based sensor installation. By using a flat sensor that contacts the stem surface without penetrating deep into the plant, it takes out the measurement capability while eliminating the harmful drilling and epidermis removal processes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flat sensor design concentrates the measurement function at a localized surface contact point rather than requiring deep penetration into the plant stem. This local quality approach allows measurement without widespread structural damage, as the sensor only interacts with the outer stem surface.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If sensors with diameter of 2 to 3 mm or more and length of 2 to 3 cm or more are used, then temperature difference measurement is accurate, but the device cannot be applied to plants with stem diameter of less than 20 cm

Engineering Contradiction:
Improvetemperature difference measurementVSAvoidapplicability to small-stemmed plants
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The invention changes the critical parameters of the sensor design: reducing the sensor dimensions from rod-shaped (2-3 mm diameter, 2-3 cm length) to flat configuration, and changing the installation method from internal insertion to external surface contact. This allows accurate temperature measurement on plants with stem diameters less than 20 cm while maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If holes are formed in the tree with a drill and sensors are inserted, then sap flow rate measurement is possible, but several days must elapse after installation and the testing is destructive

Engineering Contradiction:
Improvesap flow rate measurementVSAvoidtime elapsed after installation
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The flat sensor is designed to be pre-configured for immediate surface contact measurement. No preliminary drilling or insertion time is needed, as the sensor can be directly placed on the stem surface and begin measurement immediately, eliminating the several-day waiting period required for traditional drill-based installation.

Inventive Principle:
Principle #10Preliminary action

4Measurement precision

If thin-film temperature-measurement metallic resistive elements and heater are inserted into a cut formed in the stem, then stem liquid flow measurement is enabled with reduced adverse effect, but the plant tissue is still damaged

Engineering Contradiction:
Improvestem liquid flow measurementVSAvoidplant tissue damage
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The invention extracts the measurement function from invasive internal insertion and relocates it to non-invasive external surface contact. By taking out the need for cuts and internal placement, the sensor enables stem liquid flow measurement without damaging plant tissue.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flat sensor acts as an intermediary that measures temperature on the external stem surface without requiring direct internal contact with plant tissues. This intermediary approach provides measurement data while avoiding the harmful effects of cutting and inserting sensors into the plant interior.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables long-term monitoring of water dynamics in plants, facilitating appropriate water and nutrient supply based on the plant's growing status, enhancing crop productivity and quality.

Implementation Method 1

electrical resistance probe that detects the position of a xylem

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Implementation Method 2

temperature probe that is arranged downstream of the heater-equipped temperature probe in the direction of water flow in the plant, and measures a temperature difference between the heater-equipped temperature probe and the temperature probe

Methodology Applied
Scientific EffectTemperature difference: Temperature Gradient

Implementation Method 3

heater-equipped temperature probe that is arranged upstream of the temperature probe in the direction of water flow in the plant, and measures a temperature difference between the heater-equipped temperature probe and the temperature probe

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 4

measuring movement of water (specifically, water dynamics) in a fine point of a plant

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentEP3104135B1Plant moisture movement state sensor
Publication Date: 2020.03.18 KAGAWA UNIVERSITY
  • EP3104135B1 patent drawingFigure 1
  • EP3104135B1 patent drawingFigure 2
  • EP3104135B1 patent drawingFigure 3

AI summary

To provide a plant water dynamics sensor usable for measuring the dynamics of water flowing in a fine point of a plant such as a distal end of a new branch or a pedicel. The plant water dynamics sensor comprises: a heater-equipped temperature probe 10 including a temperature sensor 11 and a heater 12; a temperature probe 20 including a temperature sensor 21; an electrical resistance probe 30 including an electrical resistance measurement electrode 33; and a support 80 that supports the probes 10, 20, and 30 while the probes are aligned parallel to each other. The position of a xylem XY can be detected based on an electrical resistance measured at the electrical resistance probe 30, so that each of the temperature sensors 11 and 21 can be arranged correctly in a position at a phloem PH or at the xylem XY. This facilitates attachment of a plant water dynamics sensor 1 and water dynamics in a plant can be measured with high accuracy.