Spore Germination And Culture Of Twelve Liverworts

Liverworts are the most primitive group of higher plants.The spore germination and protonema development is a necessary stage in the life cycle of liverworts.The study on the spore germination plays an important role in revealing inter-taxon relationship and the phylogeny of liverworts.To understand spore germination patterns and protonema development of liverworts also provides theoretical basis in exploring the artificial culture of liverworts for the large-scale exploitation and utilization.In addition,the aseptic materials can promote a deepened research of bryophyte biology and its related subjects.Therefore,this study is of great significance.In order to presents different conditions used in the sterilization of spores,the germination patterns of spore as well as the development of protonemata,four species of thalloid liverworts and eight species of leafy liverworts were included in the present study.Eight species are studied for the first time.The main results are as follows:1.By the sterilization of capsules(ruptured)from four liverworts(Asterella wallichiana(Lehm.)Grolle,Dumortiera hirsuta(Sw.)Nees),Plagiochasma appendiculatum Lehm.,and Reboulia hemisphaerica(L.)Raddi)by 0.05% sodium hypochlorite solution(1.50 m L)and 0.10% sodium hypochlorite solution(1.00 mL)respectively and cultivation in modified Knop Medium,the spore germination rate of the four species was higher than 70.00%,with a maximum of 95.72%.Three aseptic plants of Asterella wallichiana,Plagiochasma appendiculatum and Reboulia hemisphaerica were obtained within 30 days,but Dumortiera hirsuta costed 49 days.The spore germination and protonema development of eight species of leafy liverworts have been shown successfully by the sterilization of capsules(unruptured)in 0.05% sodium hypochlorite solution(5 s)and then cultivation in modified Knop medium.2.The patterns of sporeling of 12 liverwort species were observed continuously.The results showed that 1)the sporeling pattern of Asterella wallichiana,Plagiochasma appendiculatum and Reboulia hemisphaerica belongs to Reboulia type with polar spores;2)the sporeling pattern of Dumortiera hirsuta belongs to Marchantia type with apolar spores;3)the sporeling pattern of Cololejeunea raduliloba Steph.,Cololejeunea inflectens(Mitt.)Benedix,Lejeunea flava(Sw.)Nees,Lejeunea anisophylla Mont.,Colura tenuicornis(A.Evans)Steph.is of Lejeunea type;4)the sporeling pattern of Allorgella zantenii(Grolle)Bechteler belongs to Ceratolejeunea type;5)the sporeling patterns of Radula cavifolia Hampe ex Gottsche,Lindenb.et Nees and Chilocyphus cuspidatus(Ness)J.J.Engel & R.M.Schust.belong to Radula type and Nardia type,respectively.3.The spores of four thalloid species all germinated within 10 days and differentiated into gametophytes within 50 days.The spores of the eight species leafy liverworts all germinated within 6 days,and the development of protonemata in each species lasted for different periods counting from 16 days(Colura tenuicornis)to 40 days(Lejeunea anisophylla).All species were differentiated into gametophytes within 50-60 days.In the process of gametophyte differentiation,the underleaves were first differentiated,then followed by the rhizoids.4.In the same sporeling pattern no difference was found in the early germination of the spores,particularly from the spore stage to protonema stage.However,differences occurred when the development of protonema stage was into gametophyte stage.This finding indicated that the differentiation among species started in the later stage of protonama development.5.The same genus has the same sporeling pattern.However,a slight difference was observed in the development of protonemata within the same genus.