Impact of additional green light and deficit in cryptochrome 1 on photosynthetic activity and pro-/antioxidant balance in Arabidopsis thaliana

The light spectral composition acting through a set of photoreceptors, such as cryptochromes and phytochromes, plays an important role in maintaining sustainable photosynthesis. An impact of cryptochrome 1 deficiency and additions of green light (GL) against the background of red (RL) and blue (BL) (different ratios of RL:BL:GL) on the activity of the photosynthetic apparatus, the content of photosynthetic pigments, pro-/antioxidant balance, and expression of some genes in the leaves of 23-d-old Arabidopsis thaliana hy4 mutant plants was studied. The deficiency of cryptochrome 1 at RL/BL ratio of 4:1 led to a decrease in the rate of photosynthesis, photosystem II activity, and activity of ascorbate peroxidase and total peroxidase but to an increase in the content of products reacting with thiobarbituric acid. However, in the presence of additional GL, this difference for photosynthetic parameters either decreased or was absent, likely due to a GL-induced decrease in the content of active cryptochrome.

Automated summary

The composition of light spectrum, acting through photoreceptors, is crucial for sustainable photosynthesis. In this study, the effects of cryptochrome 1 deficiency and additions of green light (GL) with different ratios of red light (RL) and blue light (BL) were investigated. The results showed that deficiency of cryptochrome 1 decreased photosynthesis rate, activity of photosystem II, and antioxidant enzyme activity, while increasing the content of oxidative products. However, the presence of additional GL offset these effects, possibly due to a decrease in active cryptochrome content.