Study On Peristome Diversity And Distribution Of Mosses In Karst Fengcong Of Siya River

The peristome are found in the capsule of mosses and have the function of protecting and leading spore emission.The research on peristome at home and abroad mainly focuses on the determination and classification of the evolutionary status of mosses by using peristome structure.However,there are no systematic reports on the morphological and structural diversity of peristome and the process and mechanism of peristome controlling spore emission.The purpose of this paper was to explore the morphological and structural types and diversity of mosses in karst Fengcongs environment,to explore the relationship between peristome structure characteristics and environmental adaptation,and to reveal the process and mechanism of peristome controlling spore release.In this paper,three typical karst Fengcongs around the Siya River are selected as the field fixed-point sampling area.The experimental methods such as outdoor fixed-point observation and sampling,indoor anatomical observation and self-made equipment to control water wet movement are used.The species composition of mosses,the morphological and structural types and diversity of peristome,and the spore release process of capsule water were studied.The results were as follows:(1)Peristome types and species composition of mosses: there were 11 families,26 genera and 74 species of mosses in the study area,all of which were arthrodontae mosses,There were 26 species in acrocarpi-haplolepideae mosses,which are mainly Weissia(SDR:85.34%)of Pottiaceae,which is highly tolerant to drought environment.21 species in acrocarpi-diplolepideae mosses,is dominant in the genus Bryum(SDR:75.15%)of Bryaceae,which is born in humid environment.27 species in pleurocarpi-diplolepideae mosses,among which Brachythecium(SDR:96.79%)of Brachytheciaceae,which likes shade and dampness,is the most widely distributed.The dominant species are Weissia planifolia(SDR:100%),Bryum argenteum(SDR:62.62%),Weissia platyphylloides(SDR:60.86%),and Brachythecium garovaglioides(SDR:45.94%),Eurohypnum leptothallum(SDR:45.48%)and so on.(2)The distribution of environmental factors on the peristome type of mosses was obvious: the vegetation coverage of the three fengcong was fengcong?>fengcong ?> fengcong ?,and the light intensity of fengcong ? and ? was stronger than that of fengcong ?.The vegetation coverage of the three slope sections is the bottom > middle > top,and the humidity in the middle and top of the slope is lower than that at the bottom of the slope.The results showed that in the fengcong?with good environment,was dominated by the pleurocarpi-diplolepideae mosses,while in the fengcong ?,?with bad environment,were dominated by acrocarpi-haplolepideae mosses.At the bottom of the slope,the pleurocarpi-diplolepideae were the main type,while the middle and top of the fengcong was dominated by the acrocarpi-haplolepideae mosses.Redundancy analysis(RDA)showed that light intensity and ambient temperature were the main factors affecting the distribution of acrocarpi-haplolepideae,while the distribution of pleurocarpi-diplolepideae was strongly affected by relative humidity.(3)Morphological and structural characteristics of peristome of mosses: in this paper,three types of 7 typical arthrodontae mosses were selected as the object of study.The anatomical results of peristome showed that:(1)acrocarpi-haplolepideae: 32 peristome of Didymodon constrictus,long linear,2 ~ 3 cycles;16 peristome of Fissidens taxifoliusis,similar to the exostome tooth structure of diplolepideae,with transverse lamellae,can carry out hygroscopic movement.(2)acrocarpi-diplolepideae:the exostome tooth of Bryum argenteum were opposite to the endostome tooth,and the tip of the exostome tooth extends into the endostome tooth when closed.Dentium 16,with transverse lamellae 28 ~ 40,processus 16,with perforation,2 ~ 3 cilia;The exostome tooth opposite endostome tooth of Bryum algovicum,exostome tooth tip extending into endostome tooth when closed.Dentium 16,with transverse lamellae22 ~ 28,processus 16,with perforation,2 ~ 3 cilia;The exostome tooth opposite endostome tooth of Bryum funkii,spirally arranged along peristome mouth.Processus16,with transverse lamellae 20 ~ 22,processus 16,endostome tooth without perforation and cilia.(3)pleurocarpi-diplolepideae: the exostome tooth and endostome tooth of Brachythecium garovaglioides were alternate,and the exostome tooth wrapped the endostome tooth when closed.Dentium 16,with transverse lamellae 9~13,Pitch width,processus 16,with long perforation,without cilia;The exostome tooth of Brachythecium perminusculum are opposite to the endostome tooth.when the exostome tooth are closed,the tip of the exostome tooth extends into the endostome tooth.Dentium 16,obvious transverse lines under microscope,,processus 16,with long perforation,cilia 1~2,degenerated.(4)The hygroscopic movement experiment of Bryum algovicum showed that the peristome closed when the environment was humid,and when the humidity?65%RH,the peristome opened and the spores popped out.The spores were scattered in the form of flat throwing movement,the horizontal initial velocity was 0.23 m/s,and the horizontal distance was 13.98 mm.the scattered spores formed a wide 11.54 mm ring around the peristome.The average number of spores per dispersal was 457,and it took about 503 times to disperse the spores by peristome movement alone.The distribution of different peristome mosses in karst fengcong is different under the influence of light intensity,environmental humidity and environmental temperature,therefore,the distribution of mosses in different slope sections of fengcong showed regularly with the gradient of relative humidity.There are some differences in the peristome structure with the same peristome type mosses,which provide a reliable basis for the classification of mosses.Humidity provides the power for the opening and closing of the peristome,and together with the peristome structure controls the distance,cycle and number of spores released,thus ensuring the activity of the spores.The peristome structure determines the sporulation mode of mosses,and humidity regulates the sporulation process of peristome,both of which affect the growth and distribution of mosses.Because of this,the distribution of different peristome types of mosses on karst fengcong is obviously different.