生物结皮对古尔班通古特沙漠3种荒漠草本植物生长特性与元素吸收的影响

Effects of Biological Soil Crusts on Growth and Nutrient Uptake in Three Desert Herbs in the Gurbantunggut Desert,Northwestern China

生物结皮有可能通过物理、水文、养分循环影响与之相邻的维管植物,但二者相互关系尚存在着争议。本文以新疆古尔班通古特沙漠广泛分布的地衣结皮为研究对象,分析了生物结皮对3种荒漠草本植物:尖喙牻牛儿苗(Erodium oxyrrhynchum)、条叶庭芥(Alyssum linifolium)和琉苞菊(Hyalea pulchella)的生长及其对元素吸收的影响。研究结果表明:(1)生物结皮对3种荒漠草本植物生长的影响在生长期不同阶段存在差异。在前期,生物结皮的存在促进了植物生物量的累积;而后期,生物结皮却抑制了植物生长。生物结皮的存在显著影响了荒漠草本植物生物量的累积和冠根比。(2)生物结皮的存在显著增加了3种荒漠草本植物对N和K的吸收,而对P的吸收没有显著影响。生物结皮对3种植物Cu、Ca、Mg、Na、Cl的吸收存在种间差异。本研究结果将为该荒漠生态系统潜在的植被演替方向提供重要的科学根据。

As an important component for desert ecosystem, biological soil crusts （biocrusts） may possibly attect adjacent vascular plants via hydrology, soil erosion and nutrient cycling, while experimental evidences are still scarce and controversial. In the present research, we attempted to experimentally investigate whether and how biocrusts affect growth and nutrient uptake in vascular plants of the Gurbantunggut Desert. We conducted the experiments to examine the effects of biocrusts on growth and nutrient uptake in three widely distributed species of Erodium oxyrrhynchum, Alyssum linifolium and Hyalea pulchella. The results showed that the effects of biocrusts on the growth of three desert vascular plants were different in differem growing phases. The biomass the three species in crusted soils were higher than those in uncrusted soils in the early growth period and lower in the later part of the growing period. While biocrusts did not significantly affect the biomass allocation between shoot and root. Biocrusts also influenced nutrient uptake by plants, especially promoting uptake of N and K, while did not affect the uptake of P. The influence on uptake of other elements（Cu, Ca, Mg, Na, Cl） was species-specific. We expect to provide important scientific basis on the potential vegetation succession direction in this desert ecosystem.