Identifying conservation units is crucial for the effective conservation of threatened species. Previous cases are almost exclusively based on large-scale but coarse sampling for genetic structure analyses. Significant genetic structure can occur within a small range, and thus multiple conservation units may exist in narrowly distributed plants. However, small-scale genetic structure is often overlooked in conservation planning especially for wind-pollinated and wind-dispersed trees, largely due to the absence of dense and elaborate sampling. In this study, we focused on a representative endangered relict plant, Metasequoia glyptostroboides. Using both nuclear microsatellites (nSSRs) and chloroplast DNA (cpDNA) fragments, we sampled across the narrow distribution range of this species and determined its conservation units by exploring its genetic structure and historical demography. cpDNA haplotypes were classified into two groups, but mixed in space, suggesting that the existent wild trees of M. glyptostroboides cannot be divided into different evolutionarily significant units. However, using nSSRs, we detected strong spatial genetic structure, with significant genetic differentiation and weak gene flow between the samples in the east of the species' distribution range and other samples. The divergence between the two nSSR groups was dated to the Last Glacial Maximum (c. 19.6 kya), suggesting that such spatial genetic structure has been maintained for a long term. Therefore, these two nSSR groups should be considered as different conservation units, that is, management units, to protect intergroup genetic variations, which is likely to be the outputs of local adaptation. Our findings highlight the necessity to reveal small-scale genetic structure and population demography to improve the conservation strategies of evolutionary potential of endangered plants.

Enhalus acoroides is the largest tropic seagrass, occurring in the shallow coastal areas. In this study, we characterized the complete chloroplast genome sequence of this species. The whole chloroplast genome was 176,211 bp in length with a typical quadripartite structure, including one large single-copy (LSC) region (89,851 bp), one small single-copy (SSC) region (2150 bp), and a pair of inverted repeats (IRs) (42,105 bp). The guanine-cytosine (GC) content of this genome was 38.4%. A total of 142 genes were found in this genome, including 95 protein-coding genes, 39 tRNA genes, and 8 rRNA genes. The phylogenetic analysis indicated that E. acoroides and Thalassia hemprichii formed a distinct clade.

Ostrya rehderiana is a critically endangered plant species with only five natural individuals remaining in Tianmu Mountain,Zhejiang Province,China.To explore the seed dormancy and germination of O.rehderiana,the seeds were collected from the natural individuals in November 2008 and 2009 and manipulated in illumination incubator in different treatments.Results showed that these seeds have a water absorption rate of 20%after immerging in water for 4 h(p<0.05),indicating it was not physical dormancy(PY).The seeds have higher cumulative germination rates after short low temperature storage(4 weeks v.s.16 weeks;p<0.05), suggesting low temperature might induce seeds dormancy of O.rehderiana.To break dormancy, relative longer times(median length of germination time=54 d) of temperature above 15℃ were needed,indicating the seeds may belong to physiological dormancy(PD).The most favorable germination condition was 15/25℃ employing 400 or 600 mg?L~(-1) GA.We conclude that seeds treated with GA should be sown in a fitting condition immediately to germinate well in the ex situ conservation of O.rehderiana.In addition,it is a feasible method that seeds germinate in the nature with added GA artificially.

Metasequoia glyptostroboides is a famous living fossil. It is one of the most successfully recovered endangered species based on the number of extant individuals and the distribution range. However, previous studies have revealed low genetic variation in restored populations. This paper evaluates the natural regeneration ability of the natural and restored populations. The seed masses and germination rates of restored populations were found to be significantly lower than those in natural populations, indicating decreased regeneration ability in the restored populations. The decreased germination rate in the restored populations may be due to inbreeding depression. Very low seed germination rates show that it is very difficult for the restored populations to regenerate naturally, consistent with field surveys. This is the first report on a species that has successfully produced hundreds of millions of individuals but has difficulty in regenerating naturally. Our study highlights the role of population viability analysis in delisting or downlisting species under protection. (C) 2012 Elsevier Ltd. All rights reserved.

Premise of the study: We developed polymorphic microsatellite primers in Castanopsis sclerophylla (Lindley & Paxton) Schottky (Fagaceae), a dominant canopy tree, to provide markers for further studies on the genetic structure and mating system of this species.Methods and Results: Ten polymorphic microsatellite loci were isolated and successfully amplified in three C. sclerophylla populations (Huangshanjian, Shilin, and Guanmiao) from Chun'an, Zhejiang Province, China. The number of alleles per locus in these populations ranged from 3 to 17. The observed and expected heterozygosities were 0.100-0.977 and 0.294-0.916, respectively.Conclusions: These microsatellite loci displayed moderate or high levels of polymorphism within the examined populations, showing the utility of primers in studying the genetic variation, parentage, and mating system of C. sclerophylla.

Ruppia maritima L. (Ruppiaceae), a monoecious seagrass, is widely distributed in temperate and tropical regions. In this paper, we reported ten polymorphic microsatellite loci developed for this species. The number of alleles per locus ranged from 2 to 7, and the expected heterozygosity ranged from 0.240 to 0.701. No locus pair showed significant linkage disequilibrium. These polymorphic SSR primers will be useful in population genetic studies and clone identification of R. maritima L.

Metasequoia glyptostroboides is an endangered plant endemic to China. Eleven polymorphic microsatellite loci were successfully isolated from M. glyptostroboides . The number of alleles per locus ranged from 2 to 6. The observed ( H O ) and expected ( H E ) heterozygosities ranged from 0.1842 to 0.8421 and 0.2389 to 0.6639, respectively. Polymorphism information content ranged from 0.2172 to 0.5901. No significant linkage disequilibrium was observed between the loci. Four loci showed significant deviations from Hardy–Weinberg equilibrium. These 11 effective primer pairs are expected to be useful for further studies on population genetics, mating system analysis, and conservation genetics in M. glyptostroboides.

Pollinating fig wasps and their hosts establish a paradise for coevolution and sex ratio studies. High polymorphic molecular markers would be a great assistance for such studies. We developed 15 microsatellite markers from Wiebesia pumilae, the obligate pollinator of Ficus pumila, and estimated the polymorphism with 22 individual wasps from Yongjia County, Zhejiang of China. A total of 74 alleles were detected in the 15 loci and the alleles per locus ranged from 2 to 9. The observed (H O ) and expected (H E ) heterozygosities were 0.190–0.727 and 0.483–0.831, respectively. Significant deviation from Hardy–Weinberg equilibrium was found at seven loci due to heterozygote deficits. No locus pair showed significant linkage disequilibrium. These microsatellite markers will provide a useful tool for studying the genetic structure of W. pumilae, and its coevolution with the host F. pumila.