Phytech News

October 21, 2004

PTM-48M Phytosynthesis and Transpiration Monitor

A new all-in-one instrument for monitoring plant state and environment

Overview

PhyTech’s PTM-48M Monitor is the most comprehensive system for analysis of plant status under normal environmental conditions available today. The system performs continuous monitoring and recording of plant’s photosynthesis and transpiration rate integrated with leaf temperature, sap flow rate, stem microvariations, stem and fruit growth sensors. The PTM-48 features 12 sensor ports. Four input ports are dedicated to the self-clamping leaf chambers and additional eight ports are used for other sensors, both environmental (PAR, Air Temperature and Humidity, Soil Moisture) and Phytomonitoring (Leaf Temperature, Sap Flow Rate, Stem Microvariations, Fruit Growth, and Stem Auxanometer). The leaf chamber features a novel, self-clamping design with two channels for measuring both reference (i.e. ambient) and sample (i.e. leaf chamber) CO2 concentration. In addition, a daily transpiration rate may be evaluated by comparing the amount of water accumulated in the air dehumidifier (frigistor) water trap tubes. The standard chamber has a 20 cm2 aperture suitable for a wide variety of broad-leaf plants. The leaf chambers remain normally open operating sequentially in order that only one of the leaf chambers is closed at any given time. This ensures that continuous long-term monitoring does not impact upon leaf state.

The PTM-48 Monitor provides fully automatic continuous operation controlled by a builtin microprocessor. Sampling rate can be selected from 15, 30 and 60 minutes. The RS-232 and RS485 ports are used for communicating with the PC. The Terminal Emulator software allows controlling system setup and operation as well as data downloading and export in TXT or CSV format for further processing and analysis.

Application

The PTM-48M Monitor can be used for continuous monitoring under a wide range of environmental conditions. Outdoor applications are limited only by preventing water ingress inside leaf chambers that require protection against rain and other water jets. The instrument can be used for the following research purposes: • Effect of environmental factors on productivity, water relationships and growth of plants • Short-term estimation of plant productivity • Investigation of the productivity long-term trend • Estimating contribution of different leaves to a whole plant productivity • Comparison of the productivity of different plant varieties • Investigation of different treatments effect on productivity • Disclosing a factor that limits productivity

Specifications

Number of inputs for LC-4A chamber: 4 Standard aperture of LC-4A leaf chamber: 20 cm2 CO2 Measurement principle: Non-Dispersive Infrared CO2 concentration measurement range: 0-1000 ppm Signal noise: 2 ppm pk-pk @ 350 ppm (with signal typical averaging) Air flow range: 0.1-1 LPM Nominal air flow range: 0.5-0.9 LPM Nominal measurement range of CO2 exchange**: -20 to 20 µmolCO2m-2s-1 Number of inputs for optional sensors: 8 Input range: 0-2 Vdc Sampling rate (selectable): 15, 30, or 60 minutes. Power supply for optional sensors: +15 Vdc; -15 Vdc; +5 Vdc @ 0.3A Power requirements: 220/110/100 VAC; 50/60 Hz @ 150 W *Specifications subject to change without notice **Corresponds to about 15% divergence of a sample CO2 concentration from the reference one.

Ordering information

Typical composition of the PTM-48M Monitor: 1 x System console 4 x LC-4A leaf chambers 8 x 6 m PVC hose 2 x 1-m stainless steel tripods for leaf chambers and optional sensors 1 x PIR-1 Photosynthetic radiation sensor 1 x ATH-2 Air Temperature and Humidity sensor Software (English interface for Windows 98 and above) User’s manual (English)

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