Application of chlorophyll fluorescence as a useful tool for evaluating the influence of a gamma ray on some horticultural crops.

With the data reported in this paper, we demonstrate how the chlorophyll fluorescence analysis can be utilized in evaluating the influence of gamma rays on plants. When seedlings of five horticultural vegetables, Chinese cabbage, cucumber, tomato, lettuce, and red pepper, were irradiated with an acute dose of 50 Gy . h(-1) for 4 It, they didn't show noticeable changes in the phenotype and the maximum photochemical efficiency of photosystem II, Fv/Fm. However, the performance index (PI) of photosynthesis which is based oil the OJIP induction kinetics of chlorophyll fluorescence, was decreased in the irradiated leaves of all the plant species tested, especially in those of tomato and red pepper. Similarly, the buildup of the non-photochemical quenching (NPQ) was suppressed by the gamma irradiation. The marked inhibition of the NPQ in the irradiated leaves Of cucumber. tomato, and pepper was easily distinguishable in the respective chlorophyll fluorescence images. These data suggest that the PI and NPQ are radiation-sensitive biological parameters applicable to the plant ecological monitoring Of natural or artificial radiation environments.