Dear Andew Bae ,

Based on the symptoms you've described, it sounds like the plants may be experiencing some sort of hormonal imbalance or overproduction of growth hormones. This could be caused by a number of factors, such as a nutrient deficiency, disease, or pest infestation.

One possible cause of thickening of the stem and root could be a deficiency in micronutrients such as magnesium or zinc. Necrosis of new shoots and old leaves could be caused by a fungal or bacterial infection.

Another potential cause could be the presence of plant growth regulators (PGRs) in the growth medium. PGRs, such as cytokinins and auxins, are naturally occurring hormones that regulate plant growth and development. Overuse or improper application of PGRs can lead to abnormal growth and development.

It would be beneficial to conduct further testing to confirm the cause of the problem, such as nutrient analysis, disease and pest identification, and testing for the presence of PGRs. In the meantime, it may be helpful to adjust the growth conditions and medium composition to improve plant health.

Dear Nicolò M. Villa

thank you for your reply

I also thought that those causes caused the problem.

However, even after testing, I couldn't figure out the cause.

The same problem occurs with MS basic medium without PGR.

also, The amount of medium was sufficiently increased to reduce the deficiency of trace elements, but Not resolved.

It was not a problem of microbial contamination.

What I learned over a long period of time

This plant reacts very sensitively to light during the cultivation process.

And, the symptoms get worse after about a month of culturing the plant.

Are there other causes worth considering?

Yes, it is a light problem. Seeds germinate in dark or low light conditions, and after this, you need to ensure the roots are not exposed to light and stems and leaves to the correct light intensity and quality :)

The problem may be in not adjusting the growth environment for the plants, which led to an increase in the growth hormone in the plants .. Please make sure to adjust the temperature and lighting

Zainab Jasim

Do you mean the hormonal changes in plants according to temperature and light intensity?

That's what I suspect.

At first, it was speculated that high amounts of light might produce excessive auxin hormones in the plant.

However, the plants are grown in near-dark conditions.

then, Temperature may have an effect.

Could you explain more about the principle of what you mentioned?

Yes