Bryophytes and the symbiotic microorganisms, the pioneers of vegetation restoration in karst rocky desertification areas in southwestern China

Abstract

In karst rocky desertification areas, bryophytes coexist with algae, bacteria, and fungi on exposed calcareous rocks to form a bryophyte crust, which plays an irreplaceable role in the restoration of karst degraded ecosystems. We investigated the biodiversity of crust bryophytes in karst rocky desertification areas from Guizhou Province, China. A total of 145 species in 22 families and 56 genera were identified. According to frequency and coverage, seven candidate dominant mosses were screened out, and five drought-resistant indexes of them were measured. Hypnum leptothallum, Racopilum cuspidigerum, and Hyophila involuta have high drought adaptability. We explored the interactions between two dominant mosses (H. leptothallum, H. involuta) and the structure of microbial communities in three karst rocky desertification types. Microbial diversity and function analysis showed that both moss species and karst rocky desertification types affect microbial communities. Moss species much more strongly affected the diversity and changed the community composition of these microbial groups. Bacteria were more sensitive in the microbiome as their communities changed strongly between mosses and drought resistance factors. Moreover, several species of fungi and bacteria could be significantly associated with three drought-resistant indexes: Pro (free proline content), SOD (superoxide dismutase activity), and POD (peroxidase activity), which were closely related to the drought adaptability of mosses. Our results enforced the potential role of moss-associated microbes that are important components involved in the related biological processes when bryophytes adapted to arid habitats, or as one kind of promoters in the distribution pattern of early mosses succession in karst rocky desertification areas.

The Pioneering Role of Bryophytes in Ecological Restoration of Manganese Waste Residue Areas, Southwestern China

“…As the earliest plants on land, bryophytes are comprised of three large phyla: mosses, liverworts, and hornworts [38,39]. For a long time, bryophytes have been regarded as the pioneers of vegetation restoration with the function of water retention and pedogenesis [30,40]. As the important component of biological crusts, bryophytes have been widely studied in desert ecological restoration and karstification [40][41][42].…”

“…Mosses provide nutrient substance for the colonization of a large number of Acidobacteria in manganese waste residue areas. Proteobacteria includes four classes: α, β, c, and δ, and the ratio of the phylum was differentially varied across the different hosts [27,30,[52][53][54]. e proportion of each class varied according to the species of moss, and the relative abundance of α and c classes was greater.…”

“…e sample quadrat was set according to the actual investigation situation, and each quadrat was 1 m × 1 m. All kinds of bryophytes samples with about 2 cm thick growth substrate were collected and put in valve bags. e samples were placed in a portable freezer and transported back to the laboratory for storage at 4°C [30].…”

“…e bryophytes and their coverage areas were recorded in each quadrat [25,31]. Dominant bryophytes species were determined according to the following criteria: (1) frequency, it means the number of quadrats a species is in/the total number of quadrats × 100 [30]; and (2) S a /S t , the ratio was the meaning of coverage of each species in all quadrats. e total quadrats in this study are 20 m 2 .…”

“…e research about bryophytes and symbiotic bacteria mainly concentrated on deserts, forests, grasslands, and degraded karst areas [26][27][28][29]. Microorganisms such as bacteria and fungi that are symbiotic with bryophytes are related to its arid habitats [30].…”