title: The effect of lichen-dominated biological soil crusts on growth and physiological characteristics of three plant species in a temperate desert of northwest China.
abstract: Biocrusts (biological soil crusts) cover open spaces between vascular plants in most arid and semi-arid areas. Information on effects of biocrusts on seedling growth is controversial, and there is little information on their effects on plant growth and physiology. We examined impacts of biocrusts on growth and physiological characteristics of three habitat-typical plants, Erodium oxyrhynchum, Alyssum linifolium and Hyalea pulchella, growing in the Gurbantunggut Desert, northwest China. The influence of biocrusts on plant biomass, leaf area, leaf relative water content, photosynthesis, maximum quantum efficiency of PSII (F(v)/F(m)), chlorophyll, osmotic solutes (soluble sugars, protein, proline) and antioxidant enzymes (superoxide dismutase, catalase, peroxidase) was investigated on sites with or without biocrust cover. Biomass, leaf area, leaf water content, photosynthesis, F(v)/F(m) and chlorophyll content in crusted soils were higher than in uncrusted soils during early growth and lower later in the growth period. Soluble sugars, proline and antioxidant enzyme activity were always higher in crusted than in uncrusted soils, while soluble protein content was always lower. These findings indicate that biocrusts have different effects on these three ephemeral species during growth in this desert, primarily via effects on soil moisture, and possibly on soil nutrients. The influence of biocrusts changes during plant development: in early plant growth, biocrusts had either positive or no effect on growth and physiological parameters. However, biocrusts tended to negatively influence plants during later growth. Our results provide insights to explain why previous studies have found different effects of biocrusts on vascular plant growth.
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.|Xinjiang Normal University, Urumqi, China.
authors.forename: W W
authors.initials: WW
authors.lastname: Zhuang
authors.affiliation: Department of Biological Science, Boise State University, Boise, ID, USA.
authors.forename: M
authors.initials: M
authors.lastname: Serpe
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China.
authors.forename: Y M
authors.initials: YM
authors.lastname: Zhang
mesh_terms: D019659:Asteraceae; D018533:Biomass; D019607:Brassicaceae; D002681:China; D003889:Desert Climate; D017753:Ecosystem; D031314:Geraniaceae; D008011:Lichens; D019684:Magnoliopsida / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D010788:Photosynthesis; D012987:Soil / Q000737:chemistry*; D012988:Soil Microbiology; D014867:Water
chemical_list: D012987:Soil; D014867:Water
keywords: Biological soil crusts; growth; physiological characteristics; temperate desert; vascular plant