Abstract:

In recent years， the artificial biological soil crusts applied in land desertification has been developed to be a technology of new and green in the environment protection particular in fixing moving sand and the study of ecological restoration of desert areas. However， the yield of desert cyanobacteria and other organisms used for the cultivation of artificial biological soil crusts is a bottleneck that limits the large-scale application of this technology. Thereby， to explore the growth characteristics of mass-cultivation of desert cyanobacteria and their effect factors， seven predominated species isolating from Tengger Desert cyanobacteria crusts， including Microcolus vaginatus， Anabaena sp.， Nostoc sp.， Phormidium sp.， Scytonema sp.， Tolypothrix sp. and Scytonema javanicum， were selected as subjects. Results showed that the dry weight of desert cyanobacteria firstly quickly increased after inoculation and then slowly tend to stabilize. And， the dry weight of desert cyanobacteria under the disturbance of 6- and 12-hours was higher than that of the disturbance of 3 hours in the later cultivation. What's more， the total masses of desert cyanobacteria under the disturbance of 3-， 6- and 12-hours were 0.858-， 0.940- and 0.841-kg·pond^-1， respectively. Under the disturbance of 3- and 12-hours， the dry weight of desert cyanobacteria had a significant binomial relationship with varying temperature and a negative relationship with changes in the light intensity and the photosynthetically active radiation； also， the total mass of desert cyanobacteria was significantly positively correlated with the effective accumulated temperature. In conclusion， disturbance of 6 hours not only produced the highest total mass of desert cyanobacteria but developed the higher growth ratio of desert cyanobacteria very differently than under the disturbance of 3 hours； in the meantime， the consuming energy of desert cyanobacteria under the disturbance of 6 hours was less than that under the disturbance of 12 hours. Therefore， this study hints the disturbance duration during the growth period of desert cyanobacteria should be set to 6 hours and the effective accumulated temperature should be ≥145 ℃.

Key words: artificial biological soil crust, desert cyanobacteria, scale cultivation, disturbance duration, effective accumulated temperature