BACKGROUND: Ultraviolet B (UV-B) irradiation can influence many cellular processes. Irradiation with high UV-B doses causes @entity38 degradation, a decrease in the expression of genes associated with photosynthesis and its subsequent inhibition. On the other hand, sublethal doses of UV-B are used in post-harvest technology to prevent yellowing in storage. To address this inconsistency the effect of short, high-dose UV-B irradiation on detached @entity958 leaves was examined. RESULTS: Two different experimental models were used. After short treatment with a high dose of UV-B the @entity958 leaves were either put into darkness or exposed to constant light for up to 4  days. UV-B inhibited dark-induced @entity38 degradation in @entity958 leaves in a dose-dependent manner. The expression of photosynthesis-related genes, @entity38 content and photosynthetic efficiency were higher in UV-B -treated leaves left in darkness. UV-B treatment followed by constant light caused leaf yellowing and induced the expression of senescence-related genes. Irrespective of light treatment a high UV-B dose led to clearly visible cell death 3  days after irradiation. CONCLUSIONS: High doses of UV-B have opposing effects on leaves depending on their light status after UV treatment. In darkened leaves short UV-B treatment delays the appearance of senescence symptoms. When followed by light treatment, the same doses of UV-B result in @entity38 degradation. This restricts the potential usability of UV treatment in postharvest technology to crops which are stored in darkness.

The effect of UV-B on XXXX leaves depends on light conditions after treatment.

@entity958 :: ('3702', 'Species') :: ['Arabidopsis', 'Arabidopsis thaliana'] @entity38 :: ('MESH:D002734', 'Chemical') :: ['chlorophyll']
@entity958 :: (3702,Species) :: ['Arabidopsis']
