| As pioneer plants,bryophytes have found a set of coping strategies in extreme environments through the long-term evolution,such as the response of functional traits to the environment.In karst rock desertification ecosystems,the carbonate rock surface is a harsh habitat with intermittent strong drought and high ultraviolet radiation.With selecting the Huajiang Karst Rocky Desertification Exemplary Areas as the research area,this paper takes the epilithic bryophytes as the research object and studies it through the field investigations,samplings,identifications,experiments,species compositions,dominant groups,life forms,and floristic geographical components of stony.In this paper,combining with the investigation of rocky desertification environmental factors,the adaptability characteristics of epilithic bryophytes,which are based on functional characters to karst rocky desertification environment,are discussed through the microscopic examination and detection experiments of moss functional characters.The main results are as follows:(1)The difference in environmental factors leads to the difference in moss species composition in different scales of habitats in the Huajiang area.In this study,there are 9 families,12 genera,and 20 species,which were collected totally from the Huajiang rocky desertification area.And it have 7 families,10 genera,and 12 species in the north bank of the canyon and 8 families,11 genera,and 17 species in the south.In this region,the dominant families are Pottiaceae Hampe and Entodontaceae Kindb.,the most dominant species is the Erythrodontium julaceum(Schw(?)gr.)Paris.Meanwhile the life forms are mainly turfs and wefts,and the temperate tropical nature coexists in terms of flora.(2)The analysis of morphological characters of lithophytic bryophytes in the study area showed that the location,shading and coverage of bryophytes had significant correlation with morphological and anatomical characters.Environmental factors all have different effects on the characteristics of bryophytes such as altitude,rocky desertification grade,high temperature,humidity,light,rock temperature and rock inclination of the epiphytic surface.In terms of morphology,most stony bryophytes in the region have cuculled leaves and involuted leaves which are usually found during the drought times.Beside this,many species have papillose,serrate and yellowish green leaves.(3)The changes of peroxidase and proline contents reflect the adaptation of bryophytes to karst rocky desertification environment.By analyzing the relationships in the chlorophyll fluorescence,SPAD,proline(Pro),peroxidase(POD)of physiological traits and environmental factors,it was found a significant correlation in the SPAD,POD,Pro and chlorophyll fluorescence of lithophytic bryophytes with the banks,altitude,rock temperature,atmospheric temperature and habitat location of environmental factors.Overview the whole rock,the base part of the rock stores more soil particles flowing from the upper part,therefore its water and nutrition conditions are the best.The SPAD of the rock form the top part is low for its open and flat,and the formation of chlorophyll is inhibited by strong light with higher rock temperature.The content of Pro also showed an increasing trend with the increase of altitude,which reflected the stress resistance response of antioxidant enzymes in stony moss to the rocky desertification environment.The study is one of the important contents of revealing the ecological process of rock desertification in the response of functional traits of rock surface bryophytes to the succession process of rock desertification.Based on that,this study provides basic data for the future research on the response and adaptability of bryophytes to degraded ecological environment and even global changes,and provides basic data and theoretical support for the study of rocky desertification ecological process.It also provides scientific support for further theoretical research on vegetation restoration in rocky desertification ecosystem. |
PDF Full Text Request