活動詳細資訊 Event Information
活動詳細資訊 Event Information
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活動訊息最後更新時間 : 2017-08-31 15:04:57
開始日期 Starting Date:2017-09-08  15:30
結束日期 Ending Date:2017-09-08  16:30
會議狀態 State:確定 Definitive
主/協辦單位 Organizer:生物多樣性研究中心 Biodiversity Research Center
活動地點 Venue:跨領域科技研究大樓1 樓演講廳 Auditorium, 1st Floor, Interdisciplinary Research Building
活動備忘 Event Memo:

Abstract


        Elatostema (Urticaceae), consisting of about 500 species, is mainly distributed in the tropical to subtropical areas with a diversity center in tropical Asia. Elatostema has long been a taxonomically difficult group due to frequent homoplasy of morphological characters and numerous species with a wide distribution and complex sexual systems. The circumstances of generic delimitation among Elatostema, Elatostematoides, Pellionia and Procris are quite controversial, and the infrageneric grouping within Elatostema is also uncertain. A comprehensive phylogenetic analysis, comprising Elatostema and related Urticaceae taxa (Elatostematoides, Pellionia, and Procris), was conducted. The results showed that Elatostema s.l. can be divided into three well-supported genera: Procris, Elatostematoides and Elatostema s.a. Four strongly support subclades within Elatostema s.a. can be recognized, including Weddellia clade, Pellionia clade, Afroelatostema clade and core Elatostema clade. Homoplasy amongst the morphological characters used in this study makes it impossible to circumscribe genera using synapomorphies. Combined suites of characters, however, do enable the morphological diagnosis of Elatostema s.l. The evolutionary history of Elatostema s.a. involves in a variety of biogeographical scenarios. Two intercontinental dispersal events from Asia to Africa were identified, which are probably correlated with two warm phases peaking during Cenozoic Era, respectively. There are at least five major dispersal events within core Elatostema clade, including the two routes of origin from East Asia through Malesia to Australasia. In addition, based on previous field observation, E. cyrtandrifolium, E. oblongifolium and E. rivulare only have female individuals or female-biased species and still can produce seeds. In this study, these species are confirmed to be apomictic plants with polyploidy. The results of flow cytometric seed screen and embryogenesis further demonstrated that these species should belong to an infrequent case of obligate autonomous apomixis.



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