Aquatic plant's leaves turned dark

[Jackson Tiong]

Hi, I just bought my aquarium plant a few days ago. This morning, when I checked the plant, I found that quite a number of its leaves have turned dark, they also seemed to be rather weak and not as sturdy as the other leaves. Are these signs that the plant is withering? What should I do to it? I'm guessing its the lightning because I am using a normal desk lamp instead of a fluorescent tube

[Urban Aquaria]

Without knowing what that plant is... i'd guess its just part of the process of the plant adapting to the new tank conditions.

Some plants take longer to adapt than others, especially if they were purchased in emersed form from the LFS, those will usually shed the older emersed leaves while eventually growing new healthy submersed leaves.