HORDE HD-ZT10 Portable Plant Transpiration Rate Meter with Integrated Stomatal Conductance Measurement
| Brand | HORDE Electric |
|---|---|
| Origin | Shandong, China |
| Manufacturer Type | Direct Manufacturer |
| Country of Origin | China |
| Model | HD-ZT10 |
| Price | USD 2,750 (FOB) |
| Air Temperature Sensor | Swiss-made digital thermistor, -20–80°C, ±0.2°C accuracy, 0.1°C resolution |
| Leaf Temperature Sensor | Pt100 platinum resistance thermometer, -20–60°C, ±0.2°C accuracy, 0.1°C resolution |
| Relative Humidity Sensor | Swiss high-precision capacitive sensor, 0–100% RH, ±3% RH accuracy, 0.1% RH resolution |
| PAR Sensor | Silicon photodiode with cosine-corrected optical filter, 0–3000 µmol·m⁻²·s⁻¹, <5 µmol·m⁻²·s⁻¹ absolute error |
| Flow Control | Precision micro-flow controller, adjustable 0.0–1.5 L·min⁻¹, stability ±1% full scale |
| Leaf Chamber Dimensions | Standard 55 × 20 mm (customizable per request) |
| Operating Environment | 20–50°C ambient temperature, 0–100% RH (non-condensing) |
| Power Supply | Rechargeable 8.4 V DC Li-ion battery, ≥20 h continuous operation (no external light source) |
| Data Storage | 16 GB internal flash memory (expandable to 32 GB) |
| Data Transfer | USB 2.0 interface for direct PC export |
| Display | 3.5″ TFT color LCD, 800 × 480 resolution, sunlight-readable |
| Dimensions | 260 × 260 × 130 mm |
| Weight | 3.25 kg (main unit only) |
Overview
The HORDE HD-ZT10 is a field-deployable, closed-system portable transpiration meter engineered for quantitative assessment of stomatal conductance (gs), transpiration rate (E), and net photosynthetic assimilation (An) under ambient or controlled conditions. It operates on the principle of steady-state gas exchange analysis: by maintaining a precisely regulated airflow across a sealed leaf chamber, the instrument measures real-time differential changes in humidity, temperature, and CO2 concentration (optional add-on) between inlet and outlet air streams. Coupled with simultaneous leaf surface temperature monitoring and photosynthetically active radiation (PAR) quantification, the HD-ZT10 computes stomatal conductance using standard Penman-Monteith-derived formulations compliant with ISO 17025 traceability frameworks. Its design prioritizes metrological integrity in variable environmental settings—making it suitable for longitudinal field studies in agronomy, forest ecology, drought physiology, and climate-resilience breeding programs.
Key Features
- Integrated multi-sensor architecture: Co-located Swiss-made humidity/temperature sensors and Pt100 leaf thermistor enable simultaneous calculation of vapor pressure deficit (VPD) at leaf surface and boundary layer, critical for accurate gs derivation.
- Optically calibrated PAR sensor with cosine correction ensures spectral responsivity aligned with CIE photopic luminosity function—essential for modeling light-saturated photosynthetic capacity and quantum yield.
- Micro-flow control system delivers stable, low-turbulence airflow (0.2–1.0 L·min⁻¹) with ≤±0.2% volumetric repeatability—minimizing boundary layer artifacts during dynamic stomatal response assays.
- Sunlight-readable 3.5″ TFT display supports real-time visualization of E (mmol·m⁻²·s⁻¹), gs (mol·m⁻²·s⁻¹), leaf-to-air VPD (kPa), and PAR (µmol·m⁻²·s⁻¹), with configurable logging intervals from 1 s to 60 min.
- Onboard 16 GB non-volatile storage retains timestamped sensor arrays with metadata (GPS optional via Bluetooth module), supporting GLP-compliant data lineage without external hardware dependency.
- Ruggedized aluminum-magnesium alloy chassis (IP54-rated enclosure) withstands field deployment across temperate, arid, and subtropical biomes—validated per IEC 60529 mechanical shock and thermal cycling specifications.
Sample Compatibility & Compliance
The HD-ZT10 accommodates broadleaf, needle, and succulent specimens via its standardized 55 × 20 mm leaf chamber—adaptable to species with lamina widths ≥15 mm and thickness ≤8 mm. Chamber gasket geometry minimizes edge leakage while preserving natural leaf orientation. All sensors comply with ISO/IEC 17025 calibration hierarchies: humidity sensors are NIST-traceable to SRM 2370; temperature probes are certified per DIN EN 60751 Class A tolerance. The system meets electromagnetic compatibility requirements per EN 61326-1:2013 and conforms to CE marking directives for laboratory instrumentation. Data acquisition protocols support audit trails required under FDA 21 CFR Part 11 when paired with validated third-party software (e.g., LabChart or custom Python-based pipelines).
Software & Data Management
Raw sensor outputs are stored in CSV-compliant ASCII format with embedded UTC timestamps and sensor-specific calibration coefficients. USB 2.0 interface enables drag-and-drop file transfer to Windows/macOS/Linux platforms. HORDE provides open-source Python libraries (via PyPI) for batch processing: automatic VPD correction, outlier rejection using Tukey’s fences (IQR × 1.5), and conversion to standardized units per FAO-56 guidelines. Export modules generate plots compliant with APSA and New Phytologist formatting standards—including dual-axis time-series of gs vs. PAR and E vs. leaf temperature gradients. All firmware updates follow signed-package verification to ensure cryptographic integrity.
Applications
- Agronomic screening of stomatal responsiveness to abscisic acid (ABA) and drought priming treatments in cereal and legume crops.
- Comparative ecophysiology of native vs. invasive woody species under elevated CO2 and temperature gradient chambers.
- Validation of canopy-scale eddy covariance flux tower data through ground-truthed leaf-level parameterization.
- Teaching laboratories: Quantitative demonstration of Fick’s law of diffusion applied to water vapor transport across stomatal pores.
- Forestry research: Diurnal tracking of hydraulic conductance decline in Pinus spp. during soil moisture depletion cycles.
- Urban horticulture: Optimization of irrigation scheduling via real-time transpiration feedback in green roof substrates.
FAQ
Does the HD-ZT10 measure CO2 concentration by default?
No—the base configuration measures H2O, T, RH, PAR, and flow rate. A modular NDIR CO2 sensor (0–2000 ppm, ±1.5% FS) is available as an optional upgrade.
Can chamber dimensions be customized for large-leaf species like banana or taro?
Yes—custom chambers up to 120 × 40 mm are manufacturable with lead time of 6 weeks and require engineering review for flow uniformity validation.
Is the battery pack replaceable in the field?
Yes—the 8.4 V Li-ion module uses industry-standard 18650 cells and can be swapped using a Torx T8 driver; spare batteries are stocked globally via HORDE’s authorized distributor network.
How is sensor drift compensated during extended field deployments?
The firmware executes automated zero-point calibration every 4 hours using integrated desiccant and reference humidity buffer—documented in the audit log with pass/fail flags.
Does the device support wireless telemetry for remote stations?
Not natively—but RS-232 and TTL serial interfaces allow integration with LoRaWAN or NB-IoT gateways using third-party protocol converters (e.g., Multitech mDot).
