Ultraviolet-B radiation leads to a reduction in free polyamines in Phaseolus vulgaris L.

Increasing levels of UV-B radiation (UV-B) at the Earth's surfaceare among a suite of anthropomorphic stresses that influence plant growth anddevelopment. Several stress reactions have been shown to occur in response toUV-B, including a stimulation of antioxidant pathways and altered or increasedpigmentation. Polyamines, plant growth regulators that have been shown toincrease during stress, have also been implicated in the UV-B response. Weinvestigated the effects of UV-B radiation on the UV-B sensitive legumePhaseolus vulgaris L. Top Crop over atwo-week period. Total free polyamines showed marked decreases in response toUV-B radiation, primarily due to a decrease in putrescine. The reduction infreepolyamines was correlated with UV-B induced chlorophyll loss.