生物结皮对3种荒漠草本植物光合生理特性的影响

通过人工去除生物结皮实验，研究古尔班通古特沙漠生物结皮对3种荒漠草本植物生理特性的影响，根据生物结皮对土壤养分和水分的影响，综合分析生物结皮对3种草本植物光合生理特性的影响。结果表明，生物结皮对3种荒漠草本植物光合生理的影响基本一致，在植物生长早期，生物结皮区的尖喙牻牛儿苗（Erodium oxyrrhynchum M.Bieb.）、条叶庭荠（Alyssum linifolium Steph.ex Willd.）和琉苞菊（Hyalea pulchella（Ldb.） C.Koch）的叶片相对含水量（RWC）、净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（E）、水分利用效率（WUE）、PSⅡ最大光化学量子效率（F_v/F_m）、PSⅡ实际光化学效率（φ_PSⅡ）和叶绿素（Chl）含量均高于去除生物结皮区；但是，在植物生长后期，却是去除生物结皮区的各项生理指标高。生物结皮对3种荒漠草本植物光合生理过程的影响与其对植物生长的影响基本一致，这与土壤养分和水分状况的变化密切相关。

Effects of biological soil crusts on the photosynthetic characteristics of three desert herbs in Gurbantunggut Desert

We examined the influence of biocrusts on the photosynthetic physiology of three habitat-typical desert herbs (Erodium oxyrrhynchum M.Bieb.,Alyssum linifolium Steph.ex Willd.and Hyalea pulchella(Ldb.) C.Koch) from Gurbantunggut Desert in northwest China by biocrust removal.Based on soil nutrients and water distribution,the influence of biocrusts on plant photosynthetic characteristics was synthetically analyzed.Results showed that the effect of biocrusts on the photosynthetic characteristics of the three plant species was the same.The leaf relative water content (RWC),photosynthesis (P _n),stomatal conductance (G _s),transpiration rate (E),water use efficiency (WUE),PSⅡ photochemical efficiency (F _v/F _m),PSⅡ quantum yield (φ_PSⅡ),and chlorophyll content (Chl) of the three species in crusted soils were higher than those in uncrusted soils in the early growth period,but lower in the later growth period.Our findings indicated that the effects of biocrusts on the photosynthetic parameters of the three ephemeral species were consistent with those on growth,possibly through their effects on soil nutrients and moisture.