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Severe cimate changes in Korea have caused an increase in average
temperature and a decrease in ozone by as much as -3.8% per decade, which
can lead to increased ultraviolet (UV)-B radiation. UV-B radiation plays an
important role in photomorphogenesis. However, excessive UV-B radiation can
also decrease photosynthesis as well as cause damage to cellular DNA.

The effect of two different light sources, UV-B and natural light, were
evaluated by subjecting 18 day-old soybean plants (Glycine max Merr. var
Seoritae) to each of the two light sources. Plants were then harvested and
pigment contents, chlorophyll fluorescence, and proteomic changes were
evaluated. Carotenoids and anthocyanin content increased significantly in
plants subjected to excessive UV-B radiation. Moreover, several proteins
including ATP synthase and oxygen-evolving enhancer proteins were found to
be up-regulated in soybean leaves exposed to excessive UV-B.

However, excessive UV-B light also led to a dramatic reduction in
photosynthetic efficiency when compared to control plants. Fluorescence
imaging system determined that UV-B caused irreversible damage to
Photosystem II. These findings could help future researches in which plants
can harness the positive effects of UV-B while minimizing, if not
eliminating the unfavorable effects of UV-B.

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