Dear all,
I would like to inform you about the results of the LED light survey and the planned measures.
We got in total only 18 forms back (11 GMI, 7 MFPL) which corresponds to around 14% of total facility users.
However, negative and positive feedback was reported; let us focus on the negative topics.
Two main issues have been identified in common:
- Too wet soil conditions and thus heavy algae growth on the soil surface
- Stressed plants (anthocyanins formation, early flowering, etc.)
Add. 1:
The phytotrons and the light quality were designed and optimized towards providing best plant growth conditions; this applies unfortunately also to algae.
We assume that the lack of heat radiation, by using LED light, does not dry the soil surface in the same manner like fluorescent tubes did in the past.
In the next weeks we will test measures that could be applied towards optimal watering conditions. This will include an adjustment in the watering regime from twice a week to
once in 5 days and adjustments in the watering holding time. It will be a challenge to find a compromise facilitating best watering conditions for young and older plants;
Arabidopsis and e.g. N. benthamiana or others.
In parallel we will test different soil/sand/perlite ratios to optimize (lower) the water-holding abilities of the substrate. In case you have any suggestions/experience please do not hesitate to contact
us.
We also suggest to not use the tray lids for young plants; or at least to reduce the time from one week to 2-3 days.
Add. 2.:
Here we assume that the plant stress is caused by a too high light intensity; especially by the portion of the blue spectral range. (The wet soil (1.) might also contribute the total stress reaction).
In short, the new data and calculations indicates that the originally set values of 42% (GMI) and 46% (MFPL) were most probably too high for some of your accessions/mutants/lines.
At least they are too high to be considered as an overall standard setting.
The measured total intensity (µMol*m-2*-1) of the LED light is NOT equal to the same total intensity value of fluorescent tubes. This is mainly caused by the fact of the two different light qualities and the
resulting different distribution of individual photons over the spectral range.
Our detailed spectral measurements suggest using a setting of 32% (GMI) and 38% (MFPL) as standard; especially in case of sensitive lines and/or experiments.
This settings will give you the same amount of photons belonging to the blue- and red spectral range as by using 4 fluorescent tubes.
All of you who are already happy with using higher values (60% and even 100%) can of course keep this settings. On the other hand, also lower settings might be meaningful in some cases.
We will also prepare a table/graph showing the relation of the set value to the total measured intensity.
Please feel free to test the suggested settings in your phytotron/shelves.
How to: press both buttons at the same time until the value starts flashing, set then the desired value by pressing plus or minus button. Wait until the new setting stops flashing.
Alternatively you can also ask the facility staff to change the settings for you.
We will ask you for your feedback on this new settings in the near future.
In case of any comments or questions please do not hesitate to contact us.
Best, Jakub
P.S.: The different settings for GMI and MFPL phytotrons results from the different distance between your plants and the light source.
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Jakub Jeż |
Vienna BioCenter Core Facilities GmbH |