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Diurnal variations of chlorophyll fluorescence and CO 2 exchange of biological soil crusts in different successional stages in the Gurbantunggut Desert of northwestern China
Author(s) -
Zhang Jing,
Zhang YuanMing
Publication year - 2014
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-013-1122-1
Subject(s) - photosynthesis , lichen , moss , biological soil crust , chlorophyll fluorescence , chlorophyll a , algae , botany , biology , chlorophyll , environmental chemistry , chemistry
Biological soil crusts (BSCs) formed by different combinations of photosynthetic algae, cyanobacteria, lichens and mosses are well‐developed in the Gurbantunggut Desert of northwestern China. To investigate the different responses of BSCs to environmental factors, the diurnal variations of chlorophyll fluorescence and CO 2 exchange of BSCs in different successional stages were measured following artificial rehydration in the field. Results showed that the maximum potential quantum efficiency of PSII ( F v / F m ), the actual PSII efficiency (Φ PSII ) and the relative rate of electron transport as well as net photosynthesis of the different successional BSCs varied similarly and changed markedly with diurnal fluctuations in light and temperature. Further analyses indicated that CO 2 exchange and photosynthetic pigment content of chlorophyll (Chl) a , Chl b and carotenoids increased with the developmental level of BSCs, from cyanobacterial crust to lichen crust to moss crust. The differences in responses of BSCs to environmental factors and photosynthetic pigment content may be partially attributed to differences in species composition and morphological characteristics of the various BSCs. Overall, moss crust is better adapted to a wide range of irradiance and higher temperatures than lichen and cyanobacterial crusts. Therefore, BSCs in a later successional stage are expected to play a more important role in desertification control than those of the earlier stages.