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资助项目
0.05). For some populations, germination capacity in 12-h photoperiod was significantly higher than that in completed darkness（W-FD: P < 0.01, W-JD: P < 0.05）.Genetic variation within and among six populations was assessed using AFLP markers. Genetic diversity was higher at species level (PPL = 69.19%, HE = 0.221) than at population level (PPL = 26.22%, HE = 0.095, Is =0.140), and populations in southeast Yunnan were strongly differentiated from those in southwest Yunnan (Nei’s GST = 0.575; FST = 0.655). UPGMA analysis demonstrated a clear genetic division between the two populations from DeHong (SW Yunnan; D-JD and D-HG) and the four from WenShan (SE Yunnan; W-FD, W-LH, W-ML, and W-MG). Within-population genetic variation was significantly correlated with population isolation (r(PPL) = -0.94, P = 0.006; r(HE) = -0.85, P = 0.032; r(Is) = -0.87, P = 0.025), but not with population size (r(PPL) = 0.63, P = 0.178; r(HE) = 0.54, P = 0.268; r(Is) = 0.56, P = 0.249).","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.type_filter&advanced=false&query1=Root%2BFormation&&fq=dc.project.title_filter%3ACraigia%5C+yunnanensis%5C+W.%5C+W.%5C+Smith%5C+%5C%26%5C+W.%5C+E.%5C+Evans%5C+%5C%28Tiliaceae%5C%29%5C+is%5C+an%5C+endangered%5C+deciduous%5C+tree%5C+species%5C+which%5C+has%5C+high%5C+scientific%5C+and%5C+economic%5C+value.%5C+C.%5C+yunnanensis%5C+is%5C+seriously%5C+threatened%5C+and%5C+has%5C+been%5C+pushed%5C+to%5C+the%5C+verge%5C+of%5C+extinction%5C+due%5C+to%5C+vegetation%5C+destruction%5C+in%5C+China%5C+and%5C+consequent%5C+contraction%5C+of%5C+its%5C+distribution.%5C+Hence%2C%5C+it%5C+was%5C+listed%5C+as%5C+a%5C+nationally%5C+rare%5C+and%5C+endangered%5C+plant%5C+in%5C+1999%5C+and%5C+has%5C+also%5C+been%5C+proposed%5C+as%5C+a%5C+second%5C-ranked%5C+plant%5C+for%5C+national%5C+protection%5C+in%5C+China%5C+and%5C+included%5C+in%5C+IUCN%5C+red%5C+list.%5C+As%5C+a%5C+scientifically%5C+important%5C+and%5C+valued%5C+tree%5C+species%5C+with%5C+endangered%5C+status%2C%5C+the%5C+wild%5C+populations%5C+of%5C+C.%5C+yunnanensis%5C+therefore%5C+represent%5C+is%5C+a%5C+genetic%5C+resource%5C+that%5C+must%5C+be%5C+conserved.%5C+To%5C+provide%5C+basic%5C+information%5C+for%5C+its%5C+conservation%2C%5C+the%5C+population%5C+dynamics%5C+and%5C+population%5C+size%5C+structures%2C%5C+pollination%5C+biology%5C+and%5C+breeding%5C+system%2C%5C+eleven%5C+fitness%5C-related%5C+characters%5C+and%5C+the%5C+genetic%5C+variability%5C+based%5C+on%5C+AFLP%5C+were%5C+comprehensively%5C+studied.%5C+The%5C+main%5C+results%5C+are%5C+summarized%5C+as%5C+follows%5C%3A%5C+A%5C+total%5C+of%5C+six%5C+wild%5C+populations%5C+of%5C+C.%5C+yunnanensis%5C+were%5C+found%5C+in%5C+two%5C+disjunct%5C+regions%5C+of%5C+Yunnan%2C%5C+i.e.%5C+WenShan%5C+%5C%28SE%5C+Yunnan%5C%29%5C+and%5C+DeHong%5C+%5C%28SW%5C+Yunnan%5C%29%2C%5C+from%5C+2005%5C+to%5C+2007.%5C+Additionally%2C%5C+in%5C+all%5C+but%5C+one%5C+of%5C+the%5C+populations%5C+we%5C+detected%2C%5C+mature%5C+trees%5C+were%5C+felled%5C+between%5C+2005%5C+and%5C+2007%2C%5C+so%5C+destruction%5C+of%5C+most%5C+of%5C+these%5C+populations%5C+is%5C+ongoing.%5C+Across%5C+the%5C+six%5C+populations%5C+of%5C+extant%5C+C.%5C+yunnanensis%5C+found%5C+during%5C+our%5C+study%2C%5C+the%5C+total%5C+number%5C+of%5C+mature%5C+%5C%28reproductive%5C%29%5C+individuals%5C+detected%5C+was%5C+584%5C+in%5C+2007%EF%BC%8Cplus%5C+larger%5C+numbers%5C+of%5C+seedling%5C+and%5C+resprouts%5C+from%5C+cut%5C+trunks.%5C+The%5C+result%5C+of%5C+surveying%5C+Population%5C+structure%5C+showed%5C+that%5C+there%5C+are%5C+two%5C+regeneration%5C+types%5C+which%5C+are%5C+seedlings%5C+and%5C+sprouts.%5C+Seedlings%5C+occurred%5C+abundantly%5C+in%5C+gaps%5C+or%5C+open%5C+areas%5C+and%5C+the%5C+size%5C+class%5C+frequency%5C+distributions%5C+were%5C+often%5C+discontinuous%2C%5C+and%5C+the%5C+same%5C+general%5C+pattern%5C+occurred%5C+in%5C+all%5C+the%5C+investigated%5C+populations%5C+for%5C+juveniles%5C+and%5C+adults.%5C+The%5C+numbers%5C+of%5C+seed%5C-origin%5C+individuals%5C+did%5C+however%5C+decline%5C+sharply%5C+with%5C+increasing%5C+size%2C%5C+indicating%5C+a%5C+high%5C+mortality%5C+rate%5C+going%5C+from%5C+seedling%5C+to%5C+sapling%5C+stage%5C+may%5C+be%5C+a%5C+problem%5C+for%5C+this%5C+species.%5C+Additionally%2C%5C+the%5C+cash%5C+crop%5C+cultivation%5C+and%5C+logging%5C+seriously%5C+threaten%5C+the%5C+survival%5C+of%5C+the%5C+species.%5C+We%5C+conducted%5C+field%5C+observations%5C+and%5C+artificial%5C+pollination%5C+experiments%5C+on%5C+the%5C+floral%5C+biology%2C%5C+pollination%5C+process%5C+and%5C+breeding%5C+system%5C+of%5C+Craigia%5C+yunnanensis%5C+in%5C+Fadou%2C%5C+Xichou%5C+county%5C+of%5C+Yunnan%5C+province.%5C+The%5C+lifespan%5C+of%5C+a%5C+single%5C+hermaphrodite%5C+flower%5C+is%5C+approximately%5C+3%5C-4%5C+days.%5C+A%5C+cyme%5C+has%5C+2%5C-9%5C+flowered.%5C+The%5C+flowering%5C+period%5C+of%5C+an%5C+inflorescence%5C+is%5C+usually%5C+5%5C-14%5C+days.%5C+The%5C+flowers%5C+of%5C+C.%5C+yunnanensis%5C+were%5C+protandrous.%5C+The%5C+stamens%5C+were%5C+within%5C+petal%5C-like%5C+staminodes%5C+in%5C+the%5C+opening%5C+flowers%5C+until%5C+the%5C+flower%5C+withered.%5C+Without%5C+touchment%2C%5C+the%5C+bractlike%5C+staminodes%5C+can%E2%80%99t%5C+open.%5C+Self%5C-pollination%5C+was%5C+partially%5C+avoided%5C+by%5C+temporal%5C+and%5C+spatial%5C+isolation%5C+of%5C+male%5C+and%5C+female%5C+organs%5C+within%5C+the%5C+same%5C+flower.%5C+However%2C%5C+autogamous%5C+and%5C+geitonogamous%5C+pollination%5C+is%5C+unavoidable%5C+because%5C+of%5C+the%5C+large%5C+number%5C+of%5C+flowers%5C+on%5C+a%5C+single%5C+tree%5C+and%5C+the%5C+action%5C+of%5C+pollinators.%5C+The%5C+values%5C+of%5C+both%5C+OCI%5C+%5C%28%E2%89%A54%5C%29%5C+and%5C+P%5C%2FO%5C+%5C%281381%5C%29%5C+and%5C+the%5C+results%5C+of%5C+bagging%5C+tests%5C+indicated%5C+there%5C+was%5C+no%5C+apomixes%5C+in%5C+C.%5C+yunnanensis%5C+and%5C+the%5C+breeding%5C+system%5C+of%5C+the%5C+species%5C+was%5C+outcrossing%5C+with%5C+partial%5C+self%5C-compatibility%5C+and%5C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