Impacts of UV-A irradiation on laser-induced fluorescence spectra in UV-B damaged peanut (Arachis hypogaea L.) leaves.
Influence of ultraviolet A (UV-A) exerted on ultraviolet B (UV-B) damaged peanut leaves was examined by using the laser-induced fluorescence (LIF) method. The vitality index of the leaves was estimated from the measurement of the induction kinetics of chlorophyll fluorescence that was done in parallel with LIF spectra measurement. Visible ray irradiation of several hours to the UV-B damaged leaves recovered the vitality index of the leaves, while UV-A irradiation for the same period to the UV-B damaged leaves decreased the vitality index remarkably. No significant decrease of the vitality index was seen by the UV-A irradiation of several hours to the control (damage-less) leaves. It was understood that the UV-A irradiation to the UV-B damaged leaves causes the synergistic decrease of the vitality index. It is known that UV-absorbing pigments induced by UV-B irradiation are able to reduce not only UV penetration into the leaf but also photo-system II damage of the leaves. In this experiment, it is thought that the UV-absorbing pigments were decomposed by the UV-A irradiation and so further decreased in the vitality index of the leaves.
Fukucfi
K
K
Kisarazu National College of Technology, 2-11-1, Kiyomidai-Higashi, Kisarazu, Chiba 292-0041, Japan.
Takahashi
K
K
Tatsumoto
H
H
D010367:Arachis; D007834:Lasers; D010788:Photosynthesis; D018515:Plant Leaves; D013050:Spectrometry, Fluorescence; D014466:Ultraviolet Rays / Q000009:adverse effects*