Dear friends,

In the last weeks/months we have been investigating the plant stress issue, mainly focusing on the LED light spectrum.

Always comparing to the fluorescent tube standard.

Surprisingly, also the fluorescent tube setup shows same plant stress issues!

Which was not the case in the very beginning when we have tested and decided for the new type of soil.

See picture attached to this mail:

Phytotron: #21

Soil: Gramoflor2006; not sieved; with perlite

Light: Fluorescent tubes; LD

Watering: Flooding twice a week

Left side of the tray: WUXAL treated plants (once, after 1 month, 2ml/L)

Right side of the tray: untreated plants

Our new hypothesis focuses on the soil.

In particular, on the soil composition and the available nutrients.

From today’s point of view, it looks like the composition of the soil might have changed over the last months (without informing us); but this needs further investigation.

The automated watering system (flooding) also eventually contributes negatively to the problem by washing out nutrients; twice a week.

Also sieving might be suboptimal.

Red leaves are known to be a symptom for Phosphor/Phosphate deficiency.

We are in touch with the soil supplier and with APPN soil scientist from the BOKU to find a long-term solution.

As a quick fix

• you can fertilize your plants with WUXAL fertilizer which is available in the Facility (once after ~1month; 2ml/L; watering from the top).
• Use a long-term fertilizer (OSMOCOTE)
• Use the old type of soil ED63

Please contact Anneliese in case of questions for the quick fix.

We will keep you posted on further steps and present you soon our final results and the long-term solution.

Looking forward to your valuable feedback on your quick-fix results.

Best wishes, yours PlantS Team

Jakub Jez Head, Plant Sciences Facility T +43 1 7962324 7090 M +43 664 8084 77090 jakub.jez@vbcf.ac.at

Vienna BioCenter Core Facilities GmbH Dr. Bohr-Gasse 3 1030 Vienna Austria www.vbcf.ac.at

Chair, Austrian Plant Phenotyping Network (APPN) and Support Group Member of ESFRI EMPHASIS project

Twitter: @VBCF_PlantS

LinkedIn: www.linkedin.com/in/jezjakub

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