Abstract:

The change of chlorophyll fluorescence quenching characteristics in leaves of 8～11 years old of seven coniferous and broadleaved species was measured in different light intensities by a LI-COR photosynthesis system. The results showed that the changing patterns of photochemistry quenching (q_P) and non-photochemistry quenching (NPQ) could be expressed by equation y=a+b[1-EXP(-cx)] (x: light intensity; y: q_P or NPQ). q_P was negative relation with NPQ. It was suggested that the turning point of NPQ-light response curve could be regarded as the initial point of photoinhibiton, and the corresponding light intensity could be regarded as an index for estimating the capability against photoinhibition and the adaptability for strong light. The greater value of turning point stood for the higher capacity against strong light damage. The order of the adaptability to strong light from weak to strong among seven species was Picea meyeri, Hippophae rhamnoides, Fraxinus pennsylvanica, Platycladus orientalis, Pinus tabulaeformis, Populus alba cv. Pyramidalis, Ulmus pumila.

Key words: Coniferous and broadleaved species, chlorophyll fluorescence quenching, photoinhibition, regression equation