A Technology for Rapid Reconstruction of Moss-Dominated Soil Crusts

Reconstruction of moss-dominated soil crusts is crucial for ecological restoration. A desert moss Tortula desertorum (Broth.), the main component of biological soil crusts in the Gurbantunggut desert, was used to build a procedure for construction of moss-dominated crust. Micropropagation of desert mosses is a core technology to build biological soil crusts. Although the micropropagation of mosses has been extensively studied, little is known about that of desert mosses. Effects of media, explants, and culture temperature on regeneration potential of T. desertorum were investigated respectively in this study. The factors such as relative humidity, light intensity, and photoperiod, which might take an important role in the regeneration and development of the desert moss T. desertorum, were optimized through an orthogonal test design. The life cycle of the desert moss T. desertorum in cultivation was also investigated according to several factors affecting asexual reproduction. The results showed the explants cultivated with in situ soil had produced more protonema and shoots than those cultivated with other media. Detached leaves as explants yielded more biomass per gametophyte. It was found that a slightly higher temperature facilitated shoot growth. It should be pointed out that the favorable period for T. desertorum asexual reproduction occurred mainly in early summer, which contributes to the efficient protection of biological soil crusts. Based on the life cycle of T. desertorum in cultivation, a procedure for artificial reconstruction of moss-dominated soil crusts was established and assessed. A large number of protonema were induced to grow by breeding detached green leaves in agar-solid Knop medium after 1 month as day/night temperature and humidity were set at 20/10 degrees C and 60-85%, respectively. Moss-dominated crusts formed through transplanting protonema into sand supplemented with liquid Knop medium under day/night temperatures of 25/15 degrees C after another month.