What may cause my lettuce leaves to look like in these pictures?
I don't find any literature in my language (Bahasa Indonesia) that explain this phenomenon or find any similar images on the internet. The room temperature is about 25 degrees Celcius and the relative humidity around 55 - 65% during cultivation. The light was 24 hours straight.
I actually have two hydroponic systems that have the same lighting system. The first one I planted with lettuce that I planted on 7 September 2020 and the second one was on 3 September 2020. The picture I post was the lettuce that planted on 3 September 2020.
I don't find any problems with the younger lettuce. Their leaves are fine. But the older ones all look like in these pictures.
I thought its variety not suitable for these growing conditions, but I don't really know the variety because it's in Korean, but my supervisor called it "Bun". I attached the seed pack if you want to know. I have planted red rapid lettuce and also get this condition, but not as worse as Bun variety. Other lettuce have different problem but let's not focus on that.
I thought the lettuce bolts because they get 24 hours of light. One of the reasons for lettuce bolts because of the light duration not suitable for growth. Or because there is sometimes the water system not work well and causes the root system dry.
Can anyone shed any light on whether my assumptions are correct or not, and is there any way to not make my plant turned like this again?
Bun Lettuce with white LED light