Abstract: Enhanced UV-B radiation can cause damage to plants, and melatonin can enhance plant resistance. At present, there is no research report on the effect of melatonin on potatoes under UV-B radiation, so this experiment measured plant height, photosynthetic parameters(Pn, Gs, Ci, and Tr), fluorescence parameters(Fv/Fm, ETR, qP, and NPQ), 1, 5-bisphosphate ribulose carboxylase(Rubisco) and phosphoenolpyruvate carboxylase(PEPC), to analyze the effect of melatonin on the photosynthetic and fluorescence characteristics of potatoes under UV-B radiation, provide scientific basis for revealing the defense mechanism of melatonin against potato plants under UV-B radiation. The potato variety Hezuo 88 planted in greenhouse was used as experimental material. The concentrations of melatonin were set at 0, 25, 50, 100, 150, 200 μmol/L respectively under natural light(CK) and three enhanced UV-B radiation((2.5, 5.0, 7.5 KJ/(m²·d)).The plant height, Rubisco, PEPC, photosynthetic parameters and fluorescence parameters (except NPQ) of potato decreased after exposure to enhanced UV-B radiation, but increased after exposure to melatonin.Melatonin can improve the resistance of potato to UV-B radiation, increase the plant height and enhance its photosynthetic capacity. However, the trend of these indicators rising first and then decreasing also indicates that excessive melatonin concentration will also cause certain damage to plants.

Key words: Potato, Melatonin, UV-B radiation, Photosynthetic and fluorescent properties, Rubisco PEPC

CLC Number: 

• S532.01