LSA-2050

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Handheld Device for non-invasive Leaf Analysis

What is the LSA-2050?

The LSA-2050 is a portable chlorophyll content meter that goes far beyond chlorophyll. In a single, non-destructive measurement, it determines chlorophyll content, the maximum quantum yield of photosystem II (F_V/F_M), and the UV screening capacity of the leaf epidermis - three independent indicators of plant health captured in seconds.

This combination makes the LSA-2050 unique among handheld leaf analyzers: while conventional chlorophyll meters provide only a single parameter, the LSA-2050 delivers a comprehensive physiological fingerprint of the leaf - ideal for plant phenotyping, stress screening, and precision agriculture.

Who is it for?

The LSA-2050 is designed for plant physiologists, crop scientists, agricultural consultants, and environmental researchers who need fast, reliable data in the field. It enables high-throughput phenotypping of crops, research plants, and natural vegetation - from nitrogen management in agriculture to stress monitoring in ecology.

Research Questions the LSA-2050 Can Answer

The LSA-2050 measures multiple complementary physiological parameters rather than a single parameter. By combining chlorophyll content, Photosystem II efficiency, UV screening, and geo data, it provides a comprehensive picture of plant health and stress status - making it a powerful tool for plant research, crop management, and environmental monitoring.

When and how much nitrogen does each part of the field need?

The Nitrogen Balance Index (NBI) combines chlorophyll and flavonoid data to indicate leaf nitrogen status helping optimize fertilization timing and rate across the field.

When is the optimal harvest date?

Monitoring anthocyanin and flavonoid accumulation during fruit ripening enables objective, non-destructive tracking of maturation across the field.

Where exactly is the crop under stress?

F_V/F_M detects photoinhibition, heat damage, and drought stress before visible symptoms appear. GPS-tagged measurements create stress maps of entire fields.

Does the plant protect itself against UV radiation?

The LSA-2050 is the only handheld device that quantifies UV-B screening - revealing how well the epidermis shields the photosynthetic tissue from harmful radiation.

Which variety performs best under field conditions?

Comparing chlorophyll content, F_V/F_M, and UV screening across cultivars identifies genotypes with superior stress tolerance and photosynthetic performance. A rapid, non-destructive approach to field phenotyping.

How does water availability affect photosynthesis?

Combining F_V/F_M with UV screening changes reveals the interplay between water stress and photosynthetic capacity at each measurement location.

What does the LSA-2050 measure?

Chlorophyll Content

The LSA-2050 determines chlorophyll concentration optically via leaf transmittance, following the Cerovic method. Unlike SPAD-type chlorophyll meters, this approach maintains high accuracy even at high chlorophyll concentrations. Chlorophyll content is a direct indicator of photosynthetic capacity and leaf nitrogen status.

Maximum Quantum Yield of PSII

Using the saturation pulse method of PAM fluorometry, the instrument measures the maximum photochemical efficiency of Photosystem II after dark adaptation (F_V/F_M). This is one of the most widely used parameters in plant science - a sensitive, early indicator of photoinhibition, heat damage, drought stress, herbicide effects, and other physiological disturbances.

Radiation Screening Parameters

By exciting chlorophyll fluorescence at various wavelengths, the LSA-2050 quantifies protective screening in the UV and visible range. Distinct excitation wavebands target specific pigment groups, including hydroxycinnamic acids (UV-B) and flavonoids (UV-A), carotenoids (blue), and anthocyanins (green). This allows assessment of protective pigment accumulation and light acclimation.

Nitrogen Balance Index (NBI)

The Nitrogen Balance Index (NBI) is widely used in crop science for nitrogen management and fertilization monitoring and is an important indicator of crop growth. Since nitrogen-deficient plants accumulate more flavonoids while chlorophyll decreases, the NBI provides a reliable, non-destructive indicator of leaf nitrogen status. The parameter can be used to determine the optimal time for nitrogen fertilisation.

Pigment Changes During Fruit Ripening

The LSA-2050 enables non-destructive monitoring of secondary pigment accumulation, such as anthocyanins and flavonoids, during fruit maturation. This allows objective tracking of ripening processes in fruits such as berries and grapes. For bulky samples, the removable FR/NIR emitter module facilitates flexible measurements.

Geospatial and Positional Data

Every measurement includes GPS coordinates, leaf angle, and sun angle - recorded automatically by built-in accelerometer, gyroscope, and magnetometer. This links every physiological data point to its precise location and orientation, enabling georeferenced field mapping and transect analysis.

How does it work?

The LEAF-STATE-ANALYZER LSA-2050 integrates optical absorption measurements for chlorophyll determination with PAM fluorescence analysis of Photosystem II and multi-wavelength excitation for pigment and UV screening assessment. This unique combination allows simultaneous structural and functional characterization of leaves. Each measurement takes only seconds and is non-invasive.

Designed for Efficient Field Work

The LSA-2050 is built around practical details that make a difference during long measurement sessions. The illuminated display, intuitive button layout, and ergonomic clip mechanism allow fast, comfortable operation, even over hundreds of measurements per day. Unlike instruments with automated triggering, the dedicated start button encourages checking the measurement position before each recording, reducing errors and improving data quality. Researchers who have switched from other handheld leaf analyzers consistently highlight the improved handling and measurement workflow as a significant advantage in practice.

The following data demonstrate how the LSA-2050 reveals differences in leaf acclimation between field-grown and greenhouse-grown plants. Four-week-old bean seedlings (Phaseolus vulgaris cv. Saxa) were measured on upper and lower leaf sides under both growing conditions. he visible light intensity in the greenhouse was about one third of the field intensity, and UV radiation was virtually absent. The results show clear differences in UV screening efficiency, chlorophyll content, and F_V/F_M. This illustrates how the LSA-2050 captures the physiological fingerprint of light acclimation in a single, non-invasive measurement.

UV-B screening (Apparent Transmittance at 310 nm). Upper and lower leaf sides were investigated (see x-axis labels). Mean values of four plants per treatment are shown (error bars show 95% confidence intervals). UV-B screening was most efficient (10%) on the upper side of field-grown leaves.

Agri-PV systems combine renewable energy production with traditional agriculture, but raise a central question for perennial crops: how do trees physiologically adjust to life under solar modules? Reduced incident light and filtered UV-A change the cues that leaves use to regulate their pigment composition – and these changes can be tracked quickly and non-destructively at the leaf level.

At the Obstinformationszentrum Fränkische Schweiz in Hiltpoltstein, the LSA-2050 Leaf-State-Analyzer was used to characterise sweet cherry trees grown under two Agri-PV light regimes (33 % and 48 % light transmission) and compare them to an open-field control representing conventional cultivation. Within a single growing season, the trees showed a precise, multi-pigment acclimation.

Multi-pigment acclimation

Chlorophyll investment – chlorophyll a content decreased with shading, significantly so under the 33 % variant. Less incoming light, less pigment per leaf area.
Epidermal UV screen – flavonol content was highly significantly reduced under both Agri-PV variants (p < 0.01). With modules filtering UV-A, the protective investment is scaled back.
Stress markers – anthocyanins remained unchanged. No acute stress response was triggered.

Together, these three readings from a single non-destructive measurement let researchers distinguish acclimation from stress – essential for evaluating Agri-PV systems, screening cultivars for shade tolerance, and supporting orchard management decisions under changing light environments. The LSA-2050 delivers all three pigment values in seconds, on attached leaves, with no extraction or laboratory follow-up required.

LSA-2050

Housing

Battery-powered handheld device consisting of a control unit and a sample clip, both made of painted polyamide 12 (PA 12). The control unit is equipped with a holder for four AAA-type batteries and a USB-C connector. Two metal flat springs press the clip jaws together. The lower clip jaw is removable

Display

Backlit transflective B/W LCD display, 48 x 27 mm, 128 x 64 pixel

Control

Six control keys plus a separate START key to start a measurement

Data memory

Flash memory, 8 MB, providing memory for more than 30,000 data sets

Data transfer

USB-C port

Power supply

4 AAA (Micro) rechargeable batteries (eneloop 1.2 V/2 Ah); 4 spare batteries, automatic power/off, battery charger (100 to 240 V AC, 50-60 Hz) for 4 batteries

Operating temperature

-5 to +45 °C, non-condensing

Dimensions

maximum 26.5 cm x 7.0 cm x 3.5 cm (L x W x H)

Weight

240 g (without batteries)

Viewing area

Disk with 10 mm diameter

Upper clip jaw

Five LEDs are circularly arranged around a PIN photodiode, which is shielded from LED emission by a long-pass filter. A quartz glass disk closes the LED/photodiode compartment. Measuring light consists of 10 µs pulses given at 15 Hz except for FM determinations (100 Hz). Typical maximum emission wavelength, full width at half maximum (FWHM), and integrated intensity at 15 Hz are: UV-B, 310 nm, 15 nm, 0.1 µmol m‑2 s‑1 (0.05 W m‑2). UV-A, 365 nm, 12 nm, 0.3 µmol m‑2 s‑1 (0.1 W m‑2). Blue, 450 nm, 14 nm, 0.1 µmol m‑2 s‑1. Green, 530 nm, 27 nm, 0.1 µmol m‑2 s‑1. Red, 630 nm, 24 nm, 0.1 µmol m‑2 s‑1. The UV LEDs are only activated in the presence of a fluorescing sample

Lower clip jaw

A far red LED (peak wavelength 715 nm, FWHM 25 nm) and a near infrared LED (peak wavelength 770 nm, FWHM 30 nm) are positioned in the center of the viewing are. The LEDs are covered by a light-diffusing disk and a quartz disk

Geospatial Data

A GPS receiver, plus accelerometer, gyro- and magneto-scope sensors add geospatial information to each measurement, including the angle at which sunlight impinges on the leaf

Design

Four position intelligent charger for AA or AAA Nickel Metal Hydride (NiMH) or Nickel Cadmium (NiCd) batteries

Design

Padded plastic case with handle

Dimensions

36.0 cm x 30.5 cm x 8.0 cm (L x W x H)

Weight

920 g

Accessories

General design

Set of three small, three medium and three large light-tight bags for dark acclimation of leaves of different sizes made of aluminum foil, colored on the outside. Each bag has a 2 cm diameter central hole for non-invasive determination of chlorophyll concentration with the LSA-2050. During dark acclimation, both sides of the hole are covered by metallized PET plastic flaps. The flaps magnetically attract each other which ensures that both lie tightly on the surface of the bag. The flaps are flexibly attached to the darkening bag at one end. The other, loose end is folded slightly outwards so that the sample clip of the LSA-2050 can be guided to the hole by folding open the flaps

Dimensions

100 mm x 70 mm, 150 mm x 100 mm, 180 mm x 120 mm (small, medium, and large size, respectively)

Weight

3 g, 4 g, 5 g (small, medium, and large size, respectively)

General design

One-piece construction made of polyamide (PA12), the two jaws of the clip are pressed together by the elasticity of the material and by two neodymium magnets, each jaw has a sliding shutter for pre-darkening and an 11 mm diameter opening for chlorophyll determination.

Dimension

86 mm x 25 mm x 35 mm (L x W x H)

Weight

10 g

General Features and Graphical User Interface

The LSA-2050 software runs as firmware on the processor of the LEAF-STATE-ANALYZER LSA-2050. All data acquisition and instrument settings are carried out using the keypad on the instrument. Acoustic signals indicate start and end of the measurement. Special Windows software converts the LSA-2050 data into an Excel file. The Excel file displays all key results in a clear manner. Without exception, all individual values, from which the results are derived, are easily accessible.