| Belonging to Toona genus Meliaceae, Toona ciliata var. pubescens is deciduous, broad-leaved,fast-growing tree species. As a rare and endangered species, and with economic values and brightprospect for development. Based on investigation and analysis, ecological characteristics,phenotypic variation, genetic diversity and spatial genetic structure were studied. The main resultsare showed as follows:1. T. ciliata var. pubescens is distributed in southern China, including Zhejiang, Guodong, Guoxi,Fujian, Yunnan, Guizhou, Jiangxi, Sichuan, Anhui, Hunan and Hubei. The distribution range isbetween E 100°16′～119°40′and N24°21′～30°31′. Due to the environmental change,deforestation and low ability of recruitment, T. ciliata var. pubescens is considered as anendangered tree species. Natural populations are few in China, which mainly distribute in provincesof Jiangxi, Yunnan, Zhejiang and Anhui. The climate in distributing region is center and southernsubtropical climate. The seedlings of T. ciliata var. pubescens grow fastly in sunny place.Physiognomy is mountain and highland in distributing region. Phenotypic characteristics werestudied, including florescence, fructiferous time, leaves, fruits, seeds, seedlings. Florescence isdifferent from south to north. It blooms between the beginning of March and April in Yunnan, but atMay and June in Jiangxi and Zhejiang. The fruits mature at the middle of May and the middle ofJune in Yunnan, while at October and Novemer in Jiangxi and Zhejiang. The length of leafstalks,the length of leaves, the width of leaves, the size of fruits were analyzed. The results showed thatthese characters vary from population to population with significant differences. The weight of onehundred seeds is little and seeds have two wings, which are helpful to spread. The analysis ofgrowing traits of T. ciliata var. pubescens seedlings, such as seedling height, seedling grounddiameter, dry weight of roots, dry weight of stems, ratio of root and stem, length of roots, surfacearea of roots and volume of roots, showed a variation between families with significantdifferences. This indicated a noticeable potential for improvement. The population structure of T.ciliata var. pubescens is close to normal school. Young and old individuals are less, which showedthat the species is decaying now. Height above sea level of distributing region is between220～1800m.2. Genomic DNA was successfully extracted from fresh leaves of T. ciliata var. pubescens usingCTAB method. Microsatellite DNA was isolated from genomic DNA with improved method ofstreptavitin beads. The genomic library which enriched with microsatellite was constructed. After sequencing the positive clones, we found seventeen positive clones enriched with microsatellite.Seventeen SSR primer pairs were designed and synthesized. The factors which affected on the SSRreaction of T.ciliata var. pubescens were studied. The results showed that the optimizedconcentration of DNA is 30ng; that of dNTP is 1.5m mol·L-1 and that of primers 0.3μmol·L-1.Through above PCR system, repetitive and steady SSR reaction system was constructed.3. The study of population genetic diversity should be essential to conserve it effectively.Population genetic diversity of eight natural populations of T.ciliata var. pubescens was studiedwith 8 microsatellite loci. The results showed that a low level genetic diversity was detected in thepopulations of T.ciliata var. pubescens. Average number of alleles and effective number of alleleswere 6.4 and 2.8 respectively. The mean expected heterozygosity was 0.61. The major of geneticvariation occurred within populations, which could be concluded from the coefficient of geneticdifferentiation(FST=0.2092). The level of gene flow(Nm=0.9821) was low. Dendrogram BasedNei's (1972) Genetic distance was analyzed with UPGMA, the eight population was divided intothree subkinds.4. Population spatial genetic structure of T.ciliata var. pubescens was analyzed with 8 pairsmicrosatellite markers. The spatial genetic structure of T.ciliata var. pubescens populations wasmeasured using spatial autocorrelation coefficients to reveal fine-scale spatial patterns of geneticstructure for guiding collection in ex situ conservation. Individual plants (209) of three naturalpopulations were sampled and their specific locations mapped. Spatial autocorrelation analysissuggested that there was significant spatial genetic structure in natural population of Yifeng. Spatialautocorrelation coefficient was calculated, which revealed significant spatial structure of geneticvariation within populations of Yifeng (with significant positive autocorrelation over 0～240m).The genetic variation was found to be randomly distributed in populations of Binchuan and Shizong.The reasons for spatial genetic structure in Yifeng may be restricted seed dispersal, heterogeneity ofmicroenvironment and density of population.5. Genetic diversity of the poplations with different age and different altitude was studied usingSSR molecular markers. The results showed that genetic diversity of populations with different agewas different, the levels of diversity were Pop3(the oldests)＞Pop2(adults)＞Pop1(juveniles). Thelevel of genetic diversity was highest at the altitude of 610m. The lowest genetic diversity occuredin the population at the altitude of 300m.6. Fingerprint map of Toona Poem. was established with four pairs of SSR molecular markers. Thisis the base to classify the species of Toona Roem.7. The reason causing the species endangering probably are habitat fragmentation, immoderateexploitation and low ability of recruitment. Conservation strategies were put forward based on them, such as strengthening management, observating the change of habits, conservating rare resources.
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