Zhaoyong Shi

Diversity and distribution of arbuscular mycorrhizal fungi along altitudinal gradients in Mount Taibai of the Qinling Mountains

Elevational patterns of plant and animal diversity have been studied for centuries; however, the effects of land elevation on arbuscular mycorrhizal (AM) fungal diversity remains unclear. We examined AM fungal diversity and distribution along 19 elevation belts in Mount Taibai of the Qinling Mountains, with the aim to assess the altitudinal diversity patterns. In total, 63 AM fungal taxa belonging to 12 genera were discovered. Mycorrhizal colonization rates on roots; AM fungal spore density; and fungal species richness, evenness, and diversity had different patterns in terms of the changes of elevation. Root colonization followed a cubical parabolic pattern, with a peak and a foot at an elevation of about 2000 and 3000 m above sea level, respectively. Species richness decreased monotonically from the lowest to the highest elevations. Spore density and α-diversity exhibited a unimodal pattern and peaked at an elevation of 2107 and 1350 m, respectively. Species evenness increased monotonically at an elevation of between 1050 and 2250 m. β-Diversity also presented a basically incremental pattern along altitudinal gradients. Our findings suggest that elevation changes were the main factor governing the patterns of AM fungal diversity.

Arbuscular mycorrhizal fungi improved plant growth and nutrient acquisition of desert ephemeral Plantago minuta under variable soil water conditions

Desert ephemeral plants play an important role in desert ecosystem. Soil water availability is considered as the major restrictive factor limiting the growth of ephemeral plants. Moreover, arbuscular mycorrhizal fungi (AM fungi) are widely reported to improve the growth of desert ephemerals. The present study aimed to test the hypothesis of that AM fungi could alleviate drought stress of desert ephemeral Plantago minuta, and AM fungal functions reduced with the improvement of soil water content. A pot experiment was carried out with three levels of soil water contents (4.5%, 9.0%, and 15.8% (w/w)), and three AM inoculation treatments (Glomus mosseae, Glomus etunicatum and non-inoculation). The results indicate that mycorrhizal colonization rate decreased with the increase of soil water availability. Inoculation improved plant growth and N, P and K acquisition in both shoots and roots regardless water treatments. When comparing the two fungi, plants inoculated with G. mosseae performed better than those inoculated with G. etunicatum in terms of plant growth and nutrient acquisition. These results showed that ameliorative soil water did not suppress arbuscular mycorrhizal fungal functions in improving growth and nutrient acquisition of desert ephemeral Plantago minuta.

Forest soil autotrophic and heterotrophic respiration under different mycorrhizal strategies and their responses to temperature and precipitation

Mycorrhizal symbiosis between plant roots and mycorrhizal fungi are almost ubiquitous. These interactions contribute a largely to soil autotrophic respiration (RA), influence soil heterotrophic respiration (RH) and respond strongly to such climatic changes as temperature and precipitation. The aim of the present study was to explore how variation of temperature and precipitation influence RA and RH in global forest ecosystems that are classified by the mycorrhizal type of the dominant plants. The results show slight variation for RA and significant change for RH among different mycorrhizal strategy types. In forests with predominating arbuscular mycorrhiza (AM) the RA and RH are trifling higher than in non-AM type forests. The responses of RA and RH to temperature and precipitation were highly variable among different mycorrhizal strategies. For example, the changes of RA and RH are more dependent on precipitation than temperature in AM-forest, and temperature accounted more for their variations in forests of the other three mycorrhizal types. As far as we know, this study was the first to evaluate the influence of different mycorrhizal strategies on forest RA and RH and their response to temperature and precipitation.