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资助项目
GST,p < 0.001) and low levels of seed-based gene flow. C. debaoensis (Cycadaceae) is an endangered species restricted to the border of Guangxi and Yunnan province in southwest China. This species has been classified into two types: sand and karst, according to the soil matrix they grow on. We examined chloroplast sequence variation of the cpDNA sequences from 11 populations of this species. Significant population genetic differentiation was detected (GST= 0.684 and FST = 0.74160). There was marked genetic differentiation between populations in the sand and karst regions and no expansion was detected. Climate changes during glacial periods have had significant effects on the current distribution of cycads. The molecular phylogenetic data, together with the geographic distribution of the haplotypes, suggest that C. debaoensis experienced range contraction during glacial periods, and that the current populations are still confined to the original refugia in southwest China which have favorable habitats in glacial period. These results imply that small refugia were maintained in both sand and karst regions during the LGM (last glacial maximum). This species had no postglacial recolonization and only stayed in these refugia up to now. The low within-population diversity of C. debaoensis suggests that there were strong bottleneck events or founder effects within each separate region during the Quaternary climatic oscillations. Relatively high genetic and haplotype diversities were detected in the newly discovered populations, which located at intermediate locality of sand regions and had morphological variation; this is probably the consequence of the admixture of different haplotypes colonizing the area from separate sources. C. micholitzii occurs in the Annan Highlands in central Vietnam near the Laos border. C. bifida occurs in North Vietnam; its distribution extends across the border into adjacent localities in Guangxi and Yunnan in China. For the comparability between them,theywere considered as the same species C. micholitzii by many academicians. The cpDNA sequences from 11 populations showed that these very controversial species, C. micholitzii and C. bifida, is paraphyletic and should belong to the same species C. micholitzii. AMOVA analysis showed that the component of among-population within region/species (76.46%) was unexpectedly larger than the among-species/region component (14.97%), which also indicates that there is no justification for recognizing two species as C. micholitzii and C. bifida. This hypothesis was also supported by the geological data, especially the neotectonic history of the indo-china block, which started to move south since Oligocene and cause the geographic isolation of these two groups. Therefore, the most likely explanation to the phenotypic similarities between these two groups may be the retention of ancestral polymorphisms in the paraphyletic group due to incomplete lineage sorting. Furthermore, the similarities may also be ascribed to pollen-mediated gene flow among geographically proximate populations and/or phenotypic convergence under similar selection schemes in the same region. C.micholitzi had the higest genetic diversity (HT = 0.980,) and genetic differentiation (GST = 0.830, NST = 0.915) among the C. micholitzii complex. The high genetic diversity might be attributed to its long evolutionary history, highly diverse habitats. The ineffective mode of seed dispersal and dramatic neotectonic movement in the distribution range of this species could result in the high genetic differentiation. 2. Phylogeographic analysis based on nuclear ribosomal sequences, We sequenced the nrDNA ITS in all 27 populations sampled, 7 haplotypes were identified, among which C. micholitzii had 6, while C. multipinnata, C. longipetiolula and C. debaoensis shared the remaining one. Compared to chloroplast genes, nuclear genes had higher correlation between genetic and geographical distance, but lower interspecies differentiation (54.42% vs 25.24%). Phylogeographical structure of C. micholitzii and C.bifida based on ITS Variation was consistent with the morphology differentiation. This similar in nuclear gene should be ascribed to pollen-mediated gene flow among geographically proximate populations.Long-distance gene flow over the two groups was clearly interrupted, which brought on the nrDNA genetic differenciation between the geographically isolated groups, to a certain extent affected the morphological variation. 3. Interspecies relationships among Cycas micholitzii complex, We analysed chloroplast sequence variation of the atpB-rbcL and psbA-trnH intergenic spacers in 27 populations sampled of C. micholitzii complex, AMOVA analysis showed that the component of among-species/region component (59.21%). However, phylogenic analysis showed that the haplotypes of C. micholitzii complex couldn`t grouped into four clusters closely corresponding to the narrowly defined C. micholitzi, C. multipinnata, C. debaoensis and C. longipetiolula. We concluded that the conflict may result from several factors: firstly incomplete lineage sorting of C. micholitzii; secondly hybridization/introgression of sympatrically cycads, which would be supported by evidence base on nrDNA ITS sequences; thirdly intramolecular recombination in cpDNA of cycads; eventually the neotectonic movement in the distribution range of this 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Fah Luang University","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3AMae%5C+Fah%5C+Luang%5C+University"},{"jsname":"Mae Fah Luang University[592010200112]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3AMae%5C+Fah%5C+Luang%5C+University%5C%5B592010200112%5C%5D"},{"jsname":"Mae Fah Luang University[60201000201]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3AMae%5C+Fah%5C+Luang%5C+University%5C%5B60201000201%5C%5D"},{"jsname":"Mae Fah Luang University[666713]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3AMae%5C+Fah%5C+Luang%5C+University%5C%5B666713%5C%5D"},{"jsname":"Mushroom Research Foundation (MRF), Chiang Rai, Thailand","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3AMushroom%5C+Research%5C+Foundation%5C+%5C%28MRF%5C%29%2C%5C+Chiang%5C+Rai%2C%5C+Thailand"},{"jsname":"National Natural Science Foundation of China[31571709]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3ANational%5C+Natural%5C+Science%5C+Foundation%5C+of%5C+China%5C%5B31571709%5C%5D"},{"jsname":"National Natural Science Foundation of China[31670337]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3ANational%5C+Natural%5C+Science%5C+Foundation%5C+of%5C+China%5C%5B31670337%5C%5D"},{"jsname":"National Natural Science Foundation of China[31700285]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3ANational%5C+Natural%5C+Science%5C+Foundation%5C+of%5C+China%5C%5B31700285%5C%5D"},{"jsname":"National Science Foundation of China (NSFC)[31750110478]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3ANational%5C+Science%5C+Foundation%5C+of%5C+China%5C+%5C%28NSFC%5C%29%5C%5B31750110478%5C%5D"},{"jsname":"National Science Foundation of China (NSFC)[41761144055]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3ANational%5C+Science%5C+Foundation%5C+of%5C+China%5C+%5C%28NSFC%5C%29%5C%5B41761144055%5C%5D"},{"jsname":"National Science Foundation of China (NSFC)[41771063]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3ANational%5C+Science%5C+Foundation%5C+of%5C+China%5C+%5C%28NSFC%5C%29%5C%5B41771063%5C%5D"},{"jsname":"Plant Germplasm Resources Innovation Project of Chinese Academy of Sciences[ZSZC-012]","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3APlant%5C+Germplasm%5C+Resources%5C+Innovation%5C+Project%5C+of%5C+Chinese%5C+Academy%5C+of%5C+Sciences%5C%5BZSZC%5C-012%5C%5D"},{"jsname":"Plants respond to unpredictable alpine environments by a high degree of specialization in the structural and functional aspects of their flowers and pollination. However, few original data about the reproductive biology of these plants has been documented, particularly in the species-rich Himalaya-Hengduan Mountain regions. Incarvillea Juss. is notable for being a temperate and herbaceous member in the primarily tropical and woody family Bignoniaceae. Most species of the genus occur in alpine areas of the Himalaya-Hengduan Mountain regions. We investigated the reproductive biology of two alpine species, I. mairei and I. lutea. Incarvillea mairei was highly self-compatible, but depended on pollinators for seed production. The main pollinators were Halictus sp and Apis sp. at low altitude, and bumblebee at high altitude. Seed production was severely limited by pollinators, as indicated by supplemental hand-pollination experiments. The extended floral longevity and stigma receptivity greatly compensated for pollinator limitation. Outcrossing rates were high from 0.834 to 0.988 with altitude and cumulative inbreeding depression was 0.088, indicating a predominant outcrossing mating system. The combination of floral traits (approach herkogamy, sensitive stigma, anther appendages) and pollinator activities ensure a remarkably efficient pollination mechanism, as well as make it possible to ensure reproduction success in alpine habitats. Incarvillea lutea is self-compatible, but depends on insects for seed production. Both the fruit and seed set were high under natural conditions. The main pollinator is Halictus sp. The larger floral displays of I. lutea received more visitations, but facilitated geitonogamous pollination simultaneously. The cumulative inbreeding depression was 0.373. The corolla tube changed color with age from yellow to red. Young yellow flowers had a significant greater pollen and nectar reward. The co-occurrence of the change in amount of reward and flower color enabled I. lutea to direct pollinators to visit reproductive, highly rewarding yellow flowers. We suggest floral color change in I. lutea may serve as a mechanism for reducing geitonogamous pollination and increasing the efficiency of pollen transfer to enhance plant fitness.","jscount":"1","jsurl":"/simple-search?field1=all&field=dc.project.title_filter&advanced=false&query1=Cat%2BBa&&fq=dc.project.title_filter%3APlants%5C+respond%5C+to%5C+unpredictable%5C+alpine%5C+environments%5C+by%5C+a%5C+high%5C+degree%5C+of%5C+specialization%5C+in%5C+the%5C+structural%5C+and%5C+functional%5C+aspects%5C+of%5C+their%5C+flowers%5C+and%5C+pollination.%5C+However%2C%5C+few%5C+original%5C+data%5C+about%5C+the%5C+reproductive%5C+biology%5C+of%5C+these%5C+plants%5C+has%5C+been%5C+documented%2C%5C+particularly%5C+in%5C+the%5C+species%5C-rich%5C+Himalaya%5C-Hengduan%5C+Mountain%5C+regions.%5C+Incarvillea%5C+Juss.%5C+is%5C+notable%5C+for%5C+being%5C+a%5C+temperate%5C+and%5C+herbaceous%5C+member%5C+in%5C+the%5C+primarily%5C+tropical%5C+and%5C+woody%5C+family%5C+Bignoniaceae.%5C+Most%5C+species%5C+of%5C+the%5C+genus%5C+occur%5C+in%5C+alpine%5C+areas%5C+of%5C+the%5C+Himalaya%5C-Hengduan%5C+Mountain%5C+regions.%5C+We%5C+investigated%5C+the%5C+reproductive%5C+biology%5C+of%5C+two%5C+alpine%5C+species%2C%5C+I.%5C+mairei%5C+and%5C+I.%5C+lutea.%5C+Incarvillea%5C+mairei%5C+was%5C+highly%5C+self%5C-compatible%2C%5C+but%5C+depended%5C+on%5C+pollinators%5C+for%5C+seed%5C+production.%5C+The%5C+main%5C+pollinators%5C+were%5C+Halictus%5C+sp%5C+and%5C+Apis%5C+sp.%5C+at%5C+low%5C+altitude%2C%5C+and%5C+bumblebee%5C+at%5C+high%5C+altitude.%5C+Seed%5C+production%5C+was%5C+severely%5C+limited%5C+by%5C+pollinators%2C%5C+as%5C+indicated%5C+by%5C+supplemental%5C+hand%5C-pollination%5C+experiments.%5C+The%5C+extended%5C+floral%5C+longevity%5C+and%5C+stigma%5C+receptivity%5C+greatly%5C+compensated%5C+for%5C+pollinator%5C+limitation.%5C+Outcrossing%5C+rates%5C+were%5C+high%5C+from%5C+0.834%5C+to%5C+0.988%5C+with%5C+altitude%5C+and%5C+cumulative%5C+inbreeding%5C+depression%5C+was%5C+0.088%2C%5C+indicating%5C+a%5C+predominant%5C+outcrossing%5C+mating%5C+system.%5C+The%5C+combination%5C+of%5C+floral%5C+traits%5C+%5C%28approach%5C+herkogamy%2C%5C+sensitive%5C+stigma%2C%5C+anther%5C+appendages%5C%29%5C+and%5C+pollinator%5C+activities%5C+ensure%5C+a%5C+remarkably%5C+efficient%5C+pollination%5C+mechanism%2C%5C+as%5C+well%5C+as%5C+make%5C+it%5C+possible%5C+to%5C+ensure%5C+reproduction%5C+success%5C+in%5C+alpine%5C+habitats.%5C+Incarvillea%5C+lutea%5C+is%5C+self%5C-compatible%2C%5C+but%5C+depends%5C+on%5C+insects%5C+for%5C+seed%5C+production.%5C+Both%5C+the%5C+fruit%5C+and%5C+seed%5C+set%5C+were%5C+high%5C+under%5C+natural%5C+conditions.%5C+The%5C+main%5C+pollinator%5C+is%5C+Halictus%5C+sp.%5C+The%5C+larger%5C+floral%5C+displays%5C+of%5C+I.%5C+lutea%5C+received%5C+more%5C+visitations%2C%5C+but%5C+facilitated%5C+geitonogamous%5C+pollination%5C+simultaneously.%5C+The%5C+cumulative%5C+inbreeding%5C+depression%5C+was%5C+0.373.%5C+The%5C+corolla%5C+tube%5C+changed%5C+color%5C+with%5C+age%5C+from%5C+yellow%5C+to%5C+red.%5C+Young%5C+yellow%5C+flowers%5C+had%5C+a%5C+significant%5C+greater%5C+pollen%5C+and%5C+nectar%5C+reward.%5C+The%5C+co%5C-occurrence%5C+of%5C+the%5C+change%5C+in%5C+amount%5C+of%5C+reward%5C+and%5C+flower%5C+color%5C+enabled%5C+I.%5C+lutea%5C+to%5C+direct%5C+pollinators%5C+to%5C+visit%5C+reproductive%2C%5C+highly%5C+rewarding%5C+yellow%5C+flowers.%5C+We%5C+suggest%5C+floral%5C+color%5C+change%5C+in%5C+I.%5C+lutea%5C+may%5C+serve%5C+as%5C+a%5C+mechanism%5C+for%5C+reducing%5C+geitonogamous%5C+pollination%5C+and%5C+increasing%5C+the%5C+efficiency%5C+of%5C+pollen%5C+transfer%5C+to%5C+enhance%5C+plant%5C+fitness."},{"jsname":"lastIndexed","jscount":"2024-04-15"}],"资助项目","dc.project.title_filter")'>
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