|
|
|
|
|
|
|
|
|
|
|
|
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.citation.indexedby_filter&advanced=false&query1=GERMINATION&&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+the%5C+pollinators%5C+were%5C+required%5C+during%5C+the%5C+pollination%5C+process.%5C+The%5C+most%5C+frequent%5C+effective%5C+floral%5C+visitor%5C+was%5C+only%5C+beautiful%5C+fly%5C+%5C%28Chrysomyia%5C+megacephala%5C%29.%5C+Fruit%5C+set%5C+and%5C+seed%5C+set%5C+in%5C+natural%5C+condition%5C+were%5C+56.67%C2%B13.85%EF%BC%85%5C+and%5C+6.26%C2%B10.75%EF%BC%85%2C%5C+respectively.%5C+Therefore%2C%5C+lack%5C+of%5C+pollinators%2C%5C+low%5C+pollination%5C+efficiency%2C%5C+unavoidable%5C+geitonogamous%5C+pollination%5C+and%5C+partial%5C+self%5C-compatibility%5C+and%5C+inbreeding%5C+in%5C+small%5C+populations%5C+may%5C+account%5C+for%5C+the%5C+low%5C+fruit%5C+set%2C%5C+especially%5C+seed%5C+set.Variations%5C+in%5C+seed%5C+traits%2C%5C+seed%5C+germination%2C%5C+and%5C+seedling%5C+growth%5C+characters%5C+among%5C+six%5C+Craigia%5C+yunnanensis%5C+populations%5C+were%5C+evaluated.%5C+All%5C+seed%5C+and%5C+seedling%5C+traits%5C+exhibited%5C+significant%5C+differences%5C+among%5C+populations%5C+%5C%28P%5C+%3C%5C+0.05%5C%29.%5C+The%5C+fitness%5C+of%5C+seed%5C+as%5C+assessed%5C+by%5C+seed%5C+size%2C%5C+seed%5C+germination%5C+and%5C+seedling%5C+trait%5C+was%5C+independent%5C+of%5C+population%5C+size%2C%5C+except%5C+for%5C+the%5C+number%5C+of%5C+seeds%5C+per%5C+capsule%5C+%5C%28r%5C+%3D%5C+0.93%EF%BC%8CP%5C+%3C%5C+0.01%5C%29.%5C+Correlations%5C+between%5C+geo%5C-climatic%5C+variables%5C+of%5C+seed%5C+origin%5C+and%5C+seed%5C+and%5C+seedling%5C+related%5C+characters%5C+were%5C+insignificant%5C+%5C%28P%5C+%3E%5C+0.05%5C%29.%5C+For%5C+some%5C+populations%2C%5C+germination%5C+capacity%5C+in%5C+12%5C-h%5C+photoperiod%5C+was%5C+significantly%5C+higher%5C+than%5C+that%5C+in%5C+completed%5C+darkness%EF%BC%88W%5C-FD%5C%3A%5C+P%5C+%3C%5C+0.01%2C%5C+W%5C-JD%5C%3A%5C+P%5C+%3C%5C+0.05%EF%BC%89.Genetic%5C+variation%5C+within%5C+and%5C+among%5C+six%5C+populations%5C+was%5C+assessed%5C+using%5C+AFLP%5C+markers.%5C+Genetic%5C+diversity%5C+was%5C+higher%5C+at%5C+species%5C+level%5C+%5C%28PPL%5C+%3D%5C+69.19%25%2C%5C+HE%5C+%3D%5C+0.221%5C%29%5C+than%5C+at%5C+population%5C+level%5C+%5C%28PPL%5C+%3D%5C+26.22%25%2C%5C+HE%5C+%3D%5C+0.095%2C%5C+Is%5C+%3D0.140%5C%29%2C%5C+and%5C+populations%5C+in%5C+southeast%5C+Yunnan%5C+were%5C+strongly%5C+differentiated%5C+from%5C+those%5C+in%5C+southwest%5C+Yunnan%5C+%5C%28Nei%E2%80%99s%5C+GST%5C+%3D%5C+0.575%5C%3B%5C+FST%5C+%3D%5C+0.655%5C%29.%5C+UPGMA%5C+analysis%5C+demonstrated%5C+a%5C+clear%5C+genetic%5C+division%5C+between%5C+the%5C+two%5C+populations%5C+from%5C+DeHong%5C+%5C%28SW%5C+Yunnan%5C%3B%5C+D%5C-JD%5C+and%5C+D%5C-HG%5C%29%5C+and%5C+the%5C+four%5C+from%5C+WenShan%5C+%5C%28SE%5C+Yunnan%5C%3B%5C+W%5C-FD%2C%5C+W%5C-LH%2C%5C+W%5C-ML%2C%5C+and%5C+W%5C-MG%5C%29.%5C+Within%5C-population%5C+genetic%5C+variation%5C+was%5C+significantly%5C+correlated%5C+with%5C+population%5C+isolation%5C+%5C%28r%5C%28PPL%5C%29%5C+%3D%5C+%5C-0.94%2C%5C+P%5C+%3D%5C+0.006%5C%3B%5C+r%5C%28HE%5C%29%5C+%3D%5C+%5C-0.85%2C%5C+P%5C+%3D%5C+0.032%5C%3B%5C+r%5C%28Is%5C%29%5C+%3D%5C+%5C-0.87%2C%5C+P%5C+%3D%5C+0.025%5C%29%2C%5C+but%5C+not%5C+with%5C+population%5C+size%5C+%5C%28r%5C%28PPL%5C%29%5C+%3D%5C+0.63%2C%5C+P%5C+%3D%5C+0.178%5C%3B%5C+r%5C%28HE%5C%29%5C+%3D%5C+0.54%2C%5C+P%5C+%3D%5C+0.268%5C%3B%5C+r%5C%28Is%5C%29%5C+%3D%5C+0.56%2C%5C+P%5C+%3D%5C+0.249%5C%29."},{"jsname":"lastIndexed","jscount":"2024-04-25"}],"资助项目","dc.project.title_filter")'>
|
|
|
|
|
