Study: The effect of far red on microgreen mustard

Heliospectra's Light Test team is set up to test the effect of different wavelengths and spectrum compositions on different types of crops. In a new experiment, they test different light quality on Microgreen Mustard.

Place and duration: Heliospectra PlantLab
Species: Microgreen Mustard (Brassica juncea) cultivar “Red frills”
Lamps: Heliospectra Lightbar
PAR/Intensity: Varied between 200 and 180 µmol/m2/s
Photoperiod: 18 hours
The objective of the experiment: To test different light quality on microgreen mustard.
Results: The mustard grown with far-red were taller than that grown without far-red. Mustard grown without far-red had a darker leaf color and a stronger spicy taste.

Method
Mustard, Red Frills, were sown on the 31st of January and kept in the germination area under 24 h light for 3 days. The mustard was then moved into a vertical installation at the Heliospectra PlantLab.

The vertical set-up was built up in a growth unit of a 1.4-m2 (15-ft2) open area with reflective curtains and an open front. The photoperiod was 18 hours and the temperature was set point Day/Night 22/17 °C and humidity set to 60 %.

Two spectra were tested using the Heliospectra Lightbar, a combination of blue (450nm), red (660nm) and white LEDs (5700K), and a light intensity of 200 µmol/m2/s1. The second spectrum had an additional far-red (735nm) and a light intensity of 180 µmol/m2/s1.

Crop grown under LED treatments for 8 days, 11 days after seeding.

After 19 days, 22 days after seeding, the plants had become a bit overgrown and the differences between the treatments were visible.

Results
Far-red light has an effect on extension growth of the plant. Far-red influences the height of the plant by influencing the length of stems and the size of leaves. This was visible in the mustard grown with far-red which was taller than the plants grown without FR. The plants grown without far-red was darker in leaf color. One observation was that the plants without far-red had a stronger spicy taste. Further investigation on far-red effect on plants, not only size but other quality aspects like taste and texture, is needed.

Crop grown under LED treatments at harvest 19 days, 22 days after seeding. Left: crops without far-red; right: with far-red.

For more information:

Heliospectra
Box 5401 SE-402 29 Göteborg Sweden
Phone: +46 31 40 67 10
Fax: +46 31 83 37 82
info@heliospectra.com
www.heliospectra.com