Abstract: Chlorophyll fluorescence parameters are often used to evaluate stress status and plant physical response to stresses. To explore guidelines for nitrogen fertilization, nitrogen deficiency degree should be measured and estimated sensitively. Therefore, items including individual plant dry matter, nitrogen content and fluorescence parameters of leaves were measured among tea cultivars with different nitrogen use efficiencies. The dry matter of roots, stems, leaves and nitrogen content in leaves were declined sharply under low nitrogen stress. Compared with the low nitrogen sensitive tea cultivar ‘Benshan’, the root, stem and leaf dry weights (DW) of ‘Huangdan’ were higher under low nitrogen stress. Fo, Y(NPQ), non-photochemical quenching coefficients (NPQ) and Y(NO) increased under low nitrogen, and the fluorescence parameters of ‘Benshan’ under low nitrogen were higher than Huangdan. The maximum (Fm), primary maximum photochemical efficiency of PSⅡ(F_v/F_m), actual photosynthetic efficiency Y(Ⅱ) and coefficient of photochemical quenching (qP and qL) decreased under low nitrogen, and the fluorescence parameters of ‘Benshan’ under low nitrogen were lower than those of ‘Huangdan’. The relative high nitrogen-utility tea cultivar can reduce the damage caused by the low nitrogen stress and maintain a relatively high photosynthetic efficiency. Therefore, tea cultivar with relative high nitrogen-utility had higher yields than cultivar with low nitrogen-utility under low nitrogen stress.

Key words: low nitrogen, tea cultivar, photochemical efficiency, chlorophyll fluorescence