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Bulletin of Botanical Research ›› 2022, Vol. 42 ›› Issue (6): 1052-1061.doi: 10.7525/j.issn.1673-5102.2022.06.015

• Physiology and Ecology • Previous Articles     Next Articles

Quantitative Analysis of Leaf Photosynthetic Heterogeneity Based on Chlorophyll Fluorescence Imaging and Distribution Characteristics of Fluorescence Parameters

Wenhai HU1,2, Yi’an XIAO1,2   

  1. 1.School of Life Sciences,Jinggangshan University,Ji’an 343009
    2.Key Laboratory for Biodiversity Science and Ecological Engineering,Ji’an 343009
  • Received:2021-11-03 Online:2022-11-20 Published:2022-11-22
  • About author:HU Wenhai(1973—),male,professor,PhD,mainly engaged in research of physiological ecology of horticultural plants.
  • Supported by:
    Natural Science Foundation of China(41961005)

Abstract:

Leaf photosynthesis has high spatial heterogeneity, and chlorophyll fluorescence imaging technology provides convenience for the study of leaf photosynthetic heterogeneity, however, the analytical method for quantifying photosynthetic heterogeneity has not been widely used yet. In this study, the chlorophyll fluorescence images for the sunny and shady leaves of Ficus microcarpa in the mid subtropical region during overwintering period were obtained by using the PAM chlorophyll fluorescence imaging system(Walz, Germany), and the photosynthetic heterogeneity characteristics of sunny and shady leaves were quantitatively analyzed respectively. The results showed that the degree of photosynthetic heterogeneity and photoinhibition of sunny leaves were significantly higher than those of shady leaves for F. microcarpa during overwintering, and the coefficient of variation(CV) could be used as a quantitative index of photosynthetic heterogeneity. For sunny leaves 4.30% necrotic areas, 53.30% severe photoinhibition areas(0<Fv/Fm<0.627) and 42.27% mild photoinhibition leaf areas(0.627≤Fv/Fm<0.800) were observed under low temperature but high light condition, respectively. On the other hand, for shady leaves lesser photoinhibition and leaf necrosis were observed under low temperature and low light condition. Furthermore, the quantitative analysis of other fluorescence parameters, such as effective quantum yield of photosynthetic system Ⅱ(PSⅡ) photochemistry(Y(Ⅱ)), quantum yield of regulated energy dissipation(Y(NPQ)) and quantum yield of non-regulated energy dissipation (Y(NO)), showed that the sunny leaves possessed relatively higher photochemical ability, while the shady leaves had relatively higher heat dissipation capacity. In addition, although in winter the high light would lead to the serious accumulation of excitation pressure of the PSⅡ in sunny leaves, which indicated potential risk of serious photoinhibition stress, the necrotic areas were not large, and there were still some low-risk areas with low excitation pressure in sunny leaves. However, the shady leaves under low temperature and low light were mainly low-risk areas with low excitation pressure.

Key words: chlorophyll fluorescence imaging technology, photosynthetic heterogeneity, photoinhibition, Ficus microcarpa

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