The Qinghai-Tibetan Plateau (QTP), also known as the 'Roof of the World' or the 'Third Pole,' is famous for its extreme weather and the ecological system is extremely fragile. Due to the short growing season, low temperature and infertile soil, vegetation restoration and reconstruction is very difficult in this region.
The construction of the Qinghai-Tibet expressway will inevitably lead to the destruction of the ecological system. In this case, vegetation restoration plays a key role in environmental protection. Although many studies have reported that arbuscular mycorrhizal fungi (AMF) can promote plants to grow, improve crop resistance under stressful conditions, whether or not AMF can be used for vegetation restoration in expressway slope is still unclear, especially in cold regions, such as Qinghai-Tibetan Plateau. Therefore, we choose three species of AMF and three plant species to conduct indoor and field experiments to investigate (1) the effects of AMF on plants growth (2) the effects of AMF on plant nutrition, and to answer if AMF can be used for vegetation restoration.
Approximately 30 seeds of Puccinellia tenuiflora,Elymus dahuricus Turcz and Festuca sinensis Keng received inoculum of Glomus mosseae (GM), Glomus etunicatum (GE), and Glomus constrictum (GC) separately for inoculation treatments were sown in the pots with soil samples. The indoor experiments were conducted in a controlled greenhouse with 25oC and 14-15 h light, while the field experiments were carried out on highway slope in QTP. Plant shoots and roots were harvested separately after 8 weeks. AFM colonization rate, plant height and dry weights of shoots and roots were measured. Also, the concentrations of total Nitrogen, total Phosphorus, total K in soil and plant were analyzed.
AFM successfully colonized the three plants. The colonization rates of GM were higher significantly than GE and GC. Furthermore, AFM increased the plant height significantly compared with control. Plant height of Puccinellia tenuiflora, Elymus dahuricus Turcz and Festuca sinensis Keng was increased by 38.0%-73.5%, 32.4%-58.9% and 63.5%-98.7% individually. Moreover, mycorrhizal colonization increased both shoot and root biomass significantly for all the tested plant species. In addition, total N, P and K contents in shoots of all test plants were increased substantially by AFM treatments.
In order to prevent biological invasion, the plants used in present study are native species and the AMF are isolated from crop soils in the QTP. Although AMF improved plant growth significantly, filed results showed that the extreme environmental conditions of the QTP have brought great inhibitory effect on plant growth, compared with plant height of indoor experiments. In addition, both indoor and field experiments were carried out without fertilizer application. However, fertilizers are widely used in this region to increase vegetation yields. Therefore, the interaction of fertilizer and AMF on plant growth needs to be done in the further study.
The three AMF improve plant growth significantly by mutualistic symbiosis. The use of AMF shows great promise for vegetation restoration of expressway slope in QTP.