Chin J Plant Ecol ›› 2014, Vol. 38 ›› Issue (9): 978-989.DOI: 10.3724/SP.J.1258.2014.00092

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Physiological and biochemical responses of Syntrichia caninervis at a snowfall event in different desert habitats

YIN Ben-Feng1,2,ZHANG Yuan-Ming1,*()   

  1. 1Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, ürümqi 830011, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2014-04-01 Accepted:2014-06-24 Online:2014-04-01 Published:2014-09-22
  • Contact: ZHANG Yuan-Ming

Abstract:

Aims Water is the most constraining factor to the growth of plants in arid and semiarid regions of China. Biological soil crusts (BSCs) develop well in Gurbantünggüt Desert and Syntrichia caninervis is a dominant species in the moss crusts of this cold desert. Compared to other desert ecosystems, the Gurbantünggüt desert is home to stable and abundant snow cover in winter. The moisturizing and warming effects of snow cover provide the desert mosses with optimal growth conditions. Our objective in this study was to determine how S. caninervis shoots utilize the special snow resources under different microhabitats in early winter.
Methods The experiments were conducted from prior to the snowfall and until following the snow thawing at a long-term study site of the Gurbantünggüt Desert. We measured the physiological and biochemical characteristics in S. caninervis in three habitats: the live shrub, the dead shrub, an exposed area. The shoot water content, chlorophyll fluorescence, proline content, soluble sugar content, soluble protein content, malonyldialdehyde (MDA) content, peroxidase (POD) and superoxide dismutase (SOD) activity were compared.
Important findings The results showed that snowfall increased moss water content, the maximal photochemical efficiency of PSII (Fv/Fm), soluble sugar content, SOD and POD activity. The content of proline and MDA were reduced with snow melting. Microhabitats influenced the physiological characteristics in S. caninervis, with the effects varying with snowfall event. The water content and chlorophyll fluorescence activity were significantly higher in samples under the living shrub, while in the exposed area S. caninervis had lower water content and chlorophyll fluorescence activity regardless of the snowfall cover. These findings suggested that the S. caninervis plants under the loving shrub experienced the least stress and had the best physiological performance but weak resistance, and that those in exposed area were more stress tolerant and had poorer physiological performance. Following the snowfall, proline content, MDA content, POD and SOD activity all had significantly negative correlations with plant water content; whereas the soluble sugar and protein content displayed significantly positive correlations with plant water content. The results indicated that snowfall reduced the water stress in S. caninervis, and enhanced their physiological performance and photosynthesis, with the effects being facilitated by the low temperature of the early winter.

Key words: Gurbantünggüt Desert, microhabitats, physiological and biochemical characteristics, snowfall, Syntrichia caninervis