Seed Dormancy Characteristies Of Cyperaceae Brassicaceae And Caryophyllaceae In The Aipine Meadow On The Eastern Qinghai-Tibet Plateau

A vast amount of information related to germination and dormancy of plant seed has accumulated,but the studies reported on seed germination and dormancy community were done in tropical or temperate zone,and there was rare investigation on alpine meadow.Thus,we investigated the seeds dormancy of species in an alpine meadow on the eastern Qinghai-Tibet plateau,which might be the important supplement to the field on inter-specific seed germinability.In this experiment,the effects of phylogenetie development,seed size,light intensities,habitat and altitude on seed dormancy were investigated.The effects on dormancy levels of 93 Qinghai一Tibet plants plateau,(3 families) occurring in a aipine meadow on the eastern were studied.The results showed:1) Among the studied of three families,15 species nearly did not germinate in the Cyperaceae,over half of the species in this family were dormant,and physiological dormancy was the most important;the degree of seed dormancy were lower in the Caryophyllaceae and Cruciferae;2) The dormancy of plants in the same genus have significant relationship and the dormancy of plants in different genus in the same family have more significant relationship;3) More than 1/3 of the studied species need light but not strong light to germination,and less than 1/4 of them have the lowest dormancy percentage under strong light,only five species break their dormancy easier under totally dark than under light,and light restrain their germination;The seed dormancy of Cyperaceae is sensitive to the light;4) There was significant positive correlation between percent dormancy and seed size in families,the bigger seed,the higher percent dormancy;5) There was more significant relationship between habitats and seed dormancy in the same family than in the same genus;and there was no significant relationship between habitats and seed dormancy in all the same genus below;In the factors of affecting seed dormancy hereditary mechanism,The light difference in habitats of collection sites may not be included;6) Among the studied of three families,there was only significant difference in seed dormant proportion of Caryophyllaceae among altitudes,and significant in the genuses of Draba and Stellaria.In summary,phylogenetic relatedness had the greatest contribution to the variation in mean dormancy rate in three families,and all the life-history traits could explained lower of the variation in mean germination time among the species in the alpine meadow.Thus,seed germination and dormancy in the alpine meadow on the eastern Qinghai-Tibet plateau were affected by phylogenetic,life-history and environment factors.The ecological and phylogenetic factors should be taken into account when we discussed the difference of species.