Changes of chlorophyll fluorescence in different internodes during Phyllostachys edulis stem development

Abstract

To reveal the chlorophyll fluorescence characteristics of different internodes in the rapid growth period of Phyllostachys edulis, P. edulis shoots and stems were used as materials. The changes of the photosynthetic pigment content and chlorophyll fluorescence parameters for different internodes were studied by using a non-modulated chlorophyll fluorescence (YZQ-500) and the JIP-test data analysis method. Results showed that the content of chlorophyll a, chlorophyll b, and carotenoid in P. edulis stems significantly decreased (P < 0.05) with an increase of internodes. Light energy captured per unit area (TRo/CSo), quantum yield of electron transport per unit area (ETo/CSo), quantum yield of PS Ⅱ reaction center absorbing light energy for electron transfer (φEo), photosynthetic performance index (PIABS), and number of reaction centers (RC/CSo) significantly decreased (P < 0.05). Quantum for heat dissipation ratio (φDo), heat dissipation per unit area (DIo/CSo), and unit reaction center of wasted energy (DIo/RC) significantly decreased (P < 0.05). Since growth and development of the top and bottom internodes of P. edulis revealed activity in the middle and lower internodes having a stronger PS Ⅱ reaction center, a higher light energy conversion efficiency, and less energy dissipation enabling faster growth rates, and since photosynthetic functions of upper internodes were relatively weak meaning growth was slower, this study could be used as a reference value for clarifying the growth mechanism of P. edulis.