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Genetic variability was examined at 16 putative allozymic loci in the narrow endemic fern Polystichum otomasui. Although this species is distributed in only a few valleys within an approximately 10 km×6 km area on the Kyusyu Island of Japan, there are a relatively large number of individuals in this area. The percentage of polymorphic loci (P), the number of alleles per locus (A), the observed heterozygosity (HO) and the expected heterozygosity (HE) were 61.9, 1.93, 0.166 and 0.177, respectively, at the population level, and P, A and HE were 81.3, 2.69 and 0.199, respectively, at the species level, indicating that P. otomasui has extremely high allozymic variation for a fern species. The GST value among the 10 populations examined within the range was 0.108, suggesting that the interpopulation gene flow is high enough to impede genetic structuring. The mating system estimates, Wright's fixation index and the intragametophytic selfing rate, indicate that the species is outcrossing. High genetic variability, in spite of narrowness of the distribution, may have resulted from a recent rapid decline in the population and/or the large effective population size resulting from the extensive gene flow among the populations.

Genetic variation in an endangered tree species, Chionanthus retusus, was examined using enzyme electrophoresis. This species occurs in East Asia from Japan to Taiwan and southern China. In Japan, however, it occurs only in two restricted areas: at the northernmost tip of Tsushima Island between Japan and Korea, and in the eastern Gifu Prefecture (Tono region) of central Honshu. In the Tono region, the habitat of C. retusus is becoming fragmented under the influence of human activity and each stand contains a few individuals of C. retusus, while the population on Tsushima consists of approximately 1000 individuals. From the fossil evidence, C. retusus has been distributed continuously including the both two regions, and the present distribution is apparently relic in Japan. In contrast to the Tono population, the population of Tsushima seems to be stable. Comparing the genetic diversity and differentiation of the populations between these two regions should shed light on how a relic woody long-lived plant keeps and/or looses its genetic diversity, and how a population differentiates from other disjunct populations. Allozyme electrophoresis of 18 loci for the Tono region indicated that 22.2% of the loci are polymorphic (P) with a gene diversity of (h) 0.087. The population of Tsushima has 38.9% polymorphic loci and a gene diversity of 0.149. We could not find any spatial genetic structure of C. retusus in the Tono region by spatial autocorrelation analysis. These results suggest that considerable genetic variation is still present in the Tono region and the influence of the recent habitat fragmentation seems not so large, yet. Because C. retusus is a long-lived tree, the population history may hinder the effect of the fragmentation at present. The genetic diversity (GST) between the populations of the Tono and Tsushima is 0.280, showing the genetic differentiation between these two regions has occurred.

Using starch gel and polyacrylamide gel electrophoresis, we examined allozyme diversity in six island and seven mainland populations of Aster spathulifolius Maxim., a plant species occurring in the coastal regions of Korea and Japan. We estimated four parameters of genetic variability: percentage of polymorphic loci (P), mean number of alleles per locus (A), mean expected frequency of heterozygotes (he), and mean observed frequency of heterozygotes (ho). Genetic diversity within island populations (P = 35.6, A = 1.36, he = 0.103, and ho = 0.097) was not significantly less than within mainland populations (P = 37.1, A = 1 .37, he = 0.102, and ho = 0.092). The proportion of total genetic diversity found among the island populations (GST), among the mainland populations, and the total sample were 0.480, 0.427, and 0.491, respectively, indicating the number of migrants per generation (Nm) were 0.270, 0.335, and 0.259, respectively. This indicates that gene flow among the populations was highly restricted. Gen...

The spatial genetic structure within a population of an endangered plant, Cerastium fischerianum var. molle, was examined using spatial autocorrelation analysis. All individuals in 22 × 15 m area in a population were mapped and genotyped by three allozyme loci. Many spatial autocorrelation indices (Moran's I) were significantly larger than the expected values and their averages across three marker loci examined were positive in the short distance classes and the opposite pattern was shown in the larger distance classes, suggesting that individuals located nearly each other tend to have similar genotypes and pairs of individuals located far from each other tend to have different genotypes. Because the marker loci are considered to be neutral and the linkage disequilibria were not detected, the spatial genetic structure observed in this study seems to result from the restricted gene flow because of predominant selfing of C. fischerianum var. molle.

PREMISE OF THE STUDY: We posed two hypotheses for broad scenarios of postglacial recolonization of Korea by the warm-temperate vegetation: (1) that extant Korean populations are derived from a single refugium, or (2) that they are derived from multiple refugia. We chose a homosporous fern typical of East Asian warm-temperate vegetation, Selliguea hastata, to test which of the two scenarios is more likely and to check whether Japan contained putative glacial refugia. METHODS: Using 16 allozyme loci, we obtained genotypes of 756 individuals from 20 populations, representative of the whole distribution area in Korea (including Jeju Island), Japan, and Taiwan. We assessed genetic variability within and among populations, Wright's F-statistics, and conducted analysis of molecular variance, model-based Bayesian clustering, and bottleneck tests. KEY RESULTS: We found no allozyme variation within populations of S. hastata in mainland Korea, whereas genetic polymorphism was detected for populations from Jeju Island, Japan (in particular a population from southeastern Shikoku), and Taiwan. The levels of inbreeding within populations were high, consistent with the potential of S. hastata for intragametophytic selfing. CONCLUSIONS: Data on allelic richness together with Bayesian clustering methods suggest a pattern of postglacial recolonization of mainland Korea from a single refugium, probably located either on Jeju Island or in Japan. Jeju Island should merit the highest priority for conservation biogeography, as it played a role as a Quaternary refugium for arctic-alpine, boreal, temperate as well as warm-temperate plants, as suggested here.

We analyzed variations in chloroplast DNA (cpDNA) in the widespread herbaceous species Hosta sieboldiana and Hosta albomarginata across large portions of their geographic ranges in the Japanese archipelago. Our objective was to compare the phylogeographic histories and phylogeographic structures of the two congeneric species in the Japanese archipelago. The location of the study is Japanese archipelago. We sequenced 1380 bp of noncoding cpDNA from 45 populations of H. sieboldiana (n = 362) and 55 populations of H. albomarginata (n = 436) to assess genetic variations within and among populations across almost the entire distributions of the species in Japan. Extant patterns of geographic structure were analyzed using statistical parsimony networks and spatial analysis of molecular variance (SAMOVA). We also used Monmonier's algorithm to detect genetic barriers between regions. Relationships between the populations were examined using a neighbor-joining (NJ) method. Four haplotypes were found for H. sieboldiana, whereas eight haplotypes were identified for H. albomarginata. Total genetic haplotype diversity (hT) and within-population haplotype diversity (hS) for H. sieboldiana were 0.352 and 0.040, respectively, while the values for H. albomarginata were 0.529 and 0.085, respectively. The population differentiations (GST) for H. sieboldiana and H. albomarginata were 0.839 and 0.886, respectively. The SAMOVA analysis revealed two clusters in H. sieboldiana and four clusters in H. albomarginata. Differentiations between and among the clusters were supported by the BARRIER analysis and the NJ tree. We detected differences in the population genetic structure between the two species. We found that H. sieboldiana had lower haplotype diversity than H. albomarginata. These results may be partially explained by the difference in ecological habitats and geographic distributions between the species. Hosta albomarginata is more widely distributed than H. sieboldiana in East Asia including Russia, and this large distribution range would enable more chances to intraspecific gene flow.

We sampled 17 populations of a rare autotetraploid Aster kantoensis (Asteraceae) from three river systems located in central Japan, and studied them for allelic variation at 22 enzyme loci. There was no significant correlation between the actual population size and three genetic diversity parameters, suggesting that the effective population size was very small even for the large populations, i.e., even large populations may still have a high probability of being of recent origin and remain influenced by the founder effect. Compared to other autotetraploid species, the total genetic variation of A. kantoensis is small. The number of alleles and gene diversity of a population were not significantly different among the river systems, although the percentage of polymorphic loci was different. Genetic differentiation among river systems was larger than between populations within the river systems, thereby indicating that gene flow between river systems is small, especially between the Kinu River system and Tama or Sagami River systems.

Plant size and flower production were compared between female and hermaphroditic plants of two gynodioecious Chionographis. Frequency distribution of size and minimum size class of flowering plants were not different between two sex morphs in both Chionographis. In C. japonica ssp. hisauchiana, females produced more ovuliferous flowers than hermaphrodites, although the total number of flowers were not significantly different between two sex morphs. In contrast, hermaphrodites of C. japonica var. kurohimensis exceeded females in the total number of flowers, whereas the number of ovuliferous flowers was not significantly different between two sex morphs. Reproductive effort at flowering season is not different between females and hermaphrodites. These little differences in secondary sex characters, compared with dioecious species, are probably due to the selfing of hermaphrodites and weaknesses in gender specialization. Keywords: Chionographis, flower production, gynodioecy, plant size, secondary sex characters.

To examine the response of pollinating bees to size and sexual phases of flowers, we constructed an artificial population ofCampanula having large flower variation and presented it to potentially pollinating bees in nurseries. The pollinating bee groups (halictid, megachilid and bumble bees) responded differentially to both the flower size and to the sexual phases of the flowers. Whereas visitation rate of megachilid bees increased with the flower size, those of halictid bees and bumble bees did not show particular trends; for example, bumble bees visited almost all of the flowers consistently. Visitation frequencies to male-and female-phased flowers were significantly different between megachilids at Tokyo and halictids. This study indicates that pollinator attraction could not solely explain the evolution of the flower size inCampanula, and that other factors such as pollen transfer efficiency, should be considered.

Background During glacial periods, glacial advances caused temperate plant extirpation or retreat into localized warmer areas, and subsequent postglacial glacial retreats resulted in range expansions, which facilitated secondary contact of previously allopatric isolated lineages. The evolutionary outcomes of secondary contact, including hybrid zones, dynamic hybrid swarm, and resultant hybrid speciation, depends on the strengths of reproductive barriers that have arisen through epistatic and pleiotropic effects during allopatric isolation. The aim of this study was to demonstrate refugia isolation and subsequent secondary contact between two perennial Asclepioid species and to assess the genetic consequences of the secondary contact. We modeled the range shift of two ecologically distinct Vincetoxicum species using the species distribution model (SDM) and assessed the genetic consequences of secondary contact by combining morphological and genetic approaches. We performed morphometric analysis (592 individuals) and examined 10 nuclear microsatellites (671 individuals) in V. atratum, V. japonicum, and putative hybrid populations. Results Multivariate analysis, model-based Bayesian analysis, and non-model-based discriminant analysis of principal components confirmed the hybridization between V. atratum and V. japonicum. High pollen fertility and a lack of linkage disequilibrium suggested that the hybrid populations may be self-sustaining and have persisted since V. atratum and V. japonicum came into contact during the post-glacial period. Moreover, our findings show that the pattern of hybridization between V. atratum and V. japonicum is unidirectional and differs among populations. Geographically-isolated hybrid populations exist as genetically distinct hybrid swarms that consist of V. atratum-like genotypes, V. japonicum-like genotypes, or admixed genotypes. In addition, Bayesian-based clustering analysis and coalescent-based estimates of long-term gene flow showed patterns of introgressive hybridization in three morphologically ‘pure’ V. japonicum populations. Conclusion In this study, we demonstrated that climatic oscillations during the Quaternary period likely led to species range shift and subsequently secondary contact. Hybrid populations may be self-sustaining and have persisted since V. atratum and V. japonicum came into contact during the post-glacial period. Pattern of hybridization between V. atratum and V. japonicum is unidirectional and differs among populations. We concluded that these differences in the genetic consequences of secondary contact are caused by historical colonization processes and/or natural selection. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0587-2) contains supplementary material, which is available to authorized users.

Flooding in general, especially the urban flash flooding is one of the most destructive nature hazards. Rainfall estimates from radar network are often used as input to various hydrol ogical models for further flood warning and mitigations. The X-band dual-polarization radar network developed by the United States National Science Foundation Engineering Research Center (NSF-ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA) has shown great improvement to radar based Quantitative Precipitation Estimation (QPE), through many years of experimental validation studies. QPE and rainfall nowcasting are important goals of CASA X-band dual-polarization radar networks. This paper presents an overview of CASA QPE and nowcasting methodology. In addition, 20 rainfall events collected from the Oklahoma test best during the past 3 years are used to evaluate the networked radar rainfall products. Cross validation with a gauge network using these 20 events’ data shows that the estimates of instantaneous rain rate, 5-minute,10-minute, and hourly rainfall have normalized standard error of about 47.57%, 40.03%, 34.61% and 24.78% , respectively, whereas a low bias of about -3.83%, -2.83%,-2.77% and -3.4 5% respectively. These evaluation results demonstrate great improvement compared to the current state-of-the-art. The paper also deals with the potential role of these high-resolution rainfall products for flash floods warning and mitigation. Keywords

PREMISE OF THE STUDY: Microsatellite markers were developed for Tiarella polyphylla in Korea and Japan to study the genetic diversity and genetic structure of the species. METHODS AND RESULTS: We successfully isolated a total of nine polymorphic simple sequence repeat loci. These nine loci contained from two to eight alleles per locus. The observed and expected heterozygosities ranged from 0.000 to 0.250 and 0.000 to 0.974, respectively. CONCLUSIONS: The markers developed in this study may be used to estimate genetic diversity, genetic structure, and historical and recent gene flow in T. polyphylla, which requires conservation and management.

降雪レーダー観測を新庄盆地においておこなった.3.2cmの在来型レーダーを使用した.この研究は降雪の地形的な相違,特に風上側の丘陵地帯を越えて盆地に進入する降雪雲についておこなった一連の観測研究の1986年の解析結果である. 冬期季節風下で,極気団からの吹き出しがあるとき,日本海に面した庄内平野では降雪雲は一般に東に向かって移動する.その後出羽丘陵(山頂で海抜600から800m)を越えるか最上川峡谷を通過して新庄盆地に至る. 解析結果は,1)レーダービーム高度における雪雲のレーダー反射強度を積算した降水の水平分布が丘陵上に降る降雪と峡谷上に降る降雪に何等意味ある差異を示さなかった事である.この観測事実は降雪エコーが高度の高い丘陵より高度の低い峡谷を通り易いという傾向が無い事を示しているだろう.2)また,降雪が風下側の丘陵東麓に集中するときは,上層に逆転層が存在し,重力波による強い下降流に支配されている場合であり,他方降雪が盆地の奥深くまで活発なときは,気層が不安定で積雲活動が盆地上空まで維持される場合であると考えられる. これらの知見は一つのそして重要な観測事実であろう.

Weigela coraeensis var. coraeensis is a deciduous shrub species distributed in Japan on the mainland, Honshu, whereas its variety W. coraeensis var. fragrans is endemic to the Izu Islands located south of Honshu. We isolated eight polymorphic microsatellite loci from the species and characterized these loci for 20 individuals from a population in Honshu. The number of alleles per locus ranged from 7 to 15 and the observed and expected heterozygosities ranged from 0.60 to 0.90 and from 0.65 to 0.90, respectively. These eight polymorphic microsatellites will be useful for examining intraspecific genetic differentiation in W. coraeensis.

The spatial structure of allele frequencies for three polymorphic enzyme loci was examined in a gynodioecious population of Chionographis japonica var. kurohimensis. Spatial autocorrelation indices (Moran's I) were significantly larger in the shortest distance class than expected value, indicating that genetic similarity is shared among near-neighbor individuals. Because spatial patterns of the three loci examined showed a similar pattern, and significant linkage disequilibrium was not found among pairwise combinations of these loci, the population substructure detected in this study probably resulted from restricted gene flow because of predominant selfing in the hermaphrodites.

Intrapopulation and interpopulation variations in floral sex ratio in hermaphrodites of gynodioeciousChionographis japonica var.kurohimensis (Liliaceae) were examined. The relative ratio of male flowers to total flowers (male and perfect flowers) decreased with plant size, suggesting size-dependent gender modification. The relative ratio of male flowers per population-basis is negatively correlated with the mean number of perfect flowers. Since the number of perfect flowers proportionally increased with plant size, populations showing low maleness consist of relatively bigger plants and are considered to be in high-quality environment. On the other hand, the relative ratio of male flowers per population basis is independent of female frequency in the population. Plasticity in gender expression probably plays an important role of maintenance of gynodioecy inC. japonica var.kurohimensis.

Inter- and intrapopulation pollen-mediated gene flow was estimated in a population of Cynanchum grandifolium var. nikoense by paternity analysis of all the seeds set in 1990. By the simple exclusion procedure, the rate of genes migrating by pollen into this population was estimated to be 0.083; this value is lower than that estimated in most previous studies. Frequency distributions of intrapopulation pollen-mediated gene flow distances estimated by different methods of paternity analysis were platykurtic, and the estimated distances of realized gene flow were smaller than the interplant distance.

The selfing rate of hermaphrodites, inbreeding depression, and relative fecundity of females compared to hermaphrodites were estimated for a gynodioecious population of Chionographis japonica var. kurohimensis to test the models for the evolution of gynodioecy. In spite of the high level of selfing of hermaphrodites, significant amounts of inbreeding depression were found in seed germination and seedling growth. In addition, females produced more fertilized ovules than hermaphrodites. Nevertheless, the conditions theoretically required for maintaining gynodioecy were not satisfied even if the combined effect of these two factors was considered. Additional causes for the evolution of gynodioecy, including biparental inbreeding, are discussed. In some populations of flowering plants, females coexist with hermaphrodites, a condition known as gynodioecy. Because females reproduce sexually only by seeds, they must have some advantage to stably coexist with hermaphrodites. What these advantages are remains an open question in plant evolutionary biology. A number of theoretical works consider the basis for the evolution of gynodioecy. Lloyd (1975, 1976), Charlesworth and Charlesworth (1978), and Charlesworth and Ganders (1979) showed by evolutionarily stable strategy models that gynodioecy can evolve if the product of selfing rate of hermaphrodites (s) and inbreeding depression (d) is over 0.5 when nuclear genes control male sterility. Because viability of selfed progeny is known to be lower

This research investigates mechanisms of drifting snow accumulation, and of strong wind associated with snow clouds (developed cumulus). Detailed structure of snow drifting close to the ground was observed at several sites by use of snow particle counters (SPC), visibility meters and other meteorological instruments, simultaneously with observations of wind structure in the lower atmosphere using Doppler radar and radiosonde. Areal distributions of drifting snow were also observed as a function of time. Primary results include the following. (1) The intensity of drifting snow was found to have a strong correlation with fetch distance. Of obstacles to windward of the observation point, a river interfered with drifting snow more effectively than did a hamlet. (2) The areal distribution of drifting snow is explained fully. (3) Visibility, reflectivity and wind velocity at ground level are strongly related to drifting snow patterns.

カワラノギクの保全生物学的研究の一環として, 種子の段階の動態について検討した。多摩川で最大の生育地である秋川市草花地区の7つの個体群について, 種子捕食者であるツツミノガ属の一種の幼虫による食害を考慮して, 1991年12月 (一部は翌年12月) に開花個体密度, 個体当りの頭果数などから有効なシードレイン (単位面積当りの種子生産量) を調査した。最大の個体群において, 埋土種子の数の変化を1992年と翌年に調べた。有効なシードレインは1, 200～11,000粒/m2であった。発芽時期の後には埋土種子は少数しか残っていなかったので, 埋土種子集団の個体群の維持に対する貢献は小さいことが判明した。

The mechanisms of strong winds associated with snow clouds, and the relationship between strong winds and blowing/drifting snow, were investigated. A snowstorm occurred with a typical L-mode snow band which was generated and organized longitudinally during a continental cold-air outbreak over the Sea of Japan. Doppler radar observations revealed that the snow band consisted of small echo cells arranged along the direction of the snow band. When one of the echo cells passed, blowing/drifting snow was generated and intensified by a snow cloud-induced gust, and the horizontal visibility near the ground surface was significantly decreased. Doppler radar and radiosonde data showed that the gust was due to the cold air outflow (CAO) from the snow clouds. The leading edge of the CAO was about 9 km ahead of the center of the snow cloud and the depth of the CAO was about 600 m near the forward flank of the snow cloud. The CAO was caused by a downdraft at the center of the snow cloud, which was initiated at a height of about 1.3 km and with a velocity in excess of 1 ms−1. The observed CAO speed was explained by the theory of the gravity current.

Doppler radar analysis and a cloud-resolving storm simulator (CReSS) are used to investigate the enhancement mechanism of a localized intense precipitation system that occurred over Jeju Island, Korea, on 30 June 2006. Rain gauge data revealed intensive rainfall (> 80 mm in 100 min) over northwest of Jeju Island, and relatively low rainfall (≤ 20 mm) over the northeast of the island. The environment of the precipitation system consisted of near-saturated air (relative humidity (RH): ∼ 95%) from the surface to 700 hPa and a low lifting condensation level of 951 hPa. Doppler radar analysis revealed enhancement of the precipitation system on the northwestern lateral side (in this study, the term ‘lateral side’ refers to the sides of the mountain other than the lee-side and windward side) of Mt. Halla, the central mountain on the island (1950 m). In the region of enhancement, low-level convergence (7 × 10 − 4 s − 1 ) induced by orographic blocking with a relatively low Froude number (0.55) was observed. These observations were well simulated by a control run (CNTL) using CReSS. The simulated precipitation system was enhanced over the northwestern part of the island due to wind passing around Jeju Island, low-level convergence (1.6 × 10 − 3 s − 1 ) due to orographic blocking, and high RH (∼ 95%). In order to clarify the influence of topography and the low-level moist environment on enhancement of the precipitation system, numerical sensitivity experiments were conducted. The NOTR (no terrain) experiment produced straightforward wind without low-level convergence over the topography. Associated with these features, the CNTL rainfall amount on the northwestern lateral side of the island was 30.6% more than that produced in NOTR. A comparison of RH-controlled experiments and CNTL revealed that increasing moisture in the low-level environment resulted in greater intensity of the precipitation system. A reduction in low-level RH by as little as 2% could result in a 20.8% reduction in rainfall amount. Therefore, land areas with small, narrow, but steep topographic features, such as Jeju Island, could determine the intensity and location of the precipitation system under a moist environment during the rainy season.

In Japanese Chionographis, populations are either hermaphroditic or gynodioecious, and diploid or tetraploid. The average level of inbreeding was compared among these populations by estimating Wright's fixation index. The estimates were significant in all gynodioecious populations irrespective of ploidy level, and hermaphrodites in gynodioecious populations are considered to be selfing. In hermaphroditic populations, f values were not significant in diploid taxa but were significant in tetraploid taxa. These results suggest that gynodioecy evolved only in selfing populations and support a traditional view that the outcrossing advantage of females plays an important role in the evolution of gynodioecy. Estimates of various genetic diversity measures suggest that tetraploid hermaphroditic populations experienced population bottlenecks, and females may have been lost historically.

We conducted a molecular phylogenetic analysis of a coastal sea lavender in NW Pacific using ITS sequences of nrDNA. As a result, the ITS sequences of populations on the oceanic Daito Islands were considerably different from conspecific others in nine apomorphic substitutions. This finding indicates a distance-independent geographical structure of the genetic variation among islands in NW Pacific. The calibrated rate of nucleotide substitutions in the ITS regions within L. wrightii (average: 1.41 × 10 −8 substitutions per site per year) was higher than any other instances of substitution rates in flowering plants.

Background Nuclear genes determine the vast range of phenotypes that are responsible for the adaptive abilities of organisms in nature. Nevertheless, the evolutionary processes that generate the structures and functions of nuclear genes are only now be coming understood. The aim of our study is to isolate the alcohol dehydrogenase (Adh) genes in two distantly related legumes, and use these sequences to examine the molecular evolutionary history of this nuclear gene. Results We isolated the expressed Adh genes from two species of legumes, Sophora flavescens Ait. and Wisteria floribunda DC., by a RT-PCR based approach and found a new Adh locus in addition to homologues of the Adh genes found previously in legumes. To examine the evolution of these genes, we compared the species and gene trees and found gene duplication of the Adh loci in the legumes occurred as an ancient event. Conclusion This is the first report revealing that some legume species have at least two Adh gene loci belonging to separate clades. Phylogenetic analyses suggest that these genes resulted from relatively ancient duplication events.

Plant MADS-box genes encode transcriptional regulators that are critical for a number of developmental processes, such as the establishment of floral organ identity, flowering time, and fruit development. It appears that the MADS-box gene family has undergone considerable gene duplication and divergence within various angiosperm lineages. SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1)/Tomato MADS-box gene 3 (TM3)-like genes are members of the MADS-box gene family and have undergone repeated duplication events. Here, we isolated and characterized the SOC1/TM3-like gene TrcMADS1 from Trillium camtschatcense (Trilliaceae) to infer the ancestral function of SOC1/TM3-like genes. The alignment of SOC1/TM3-like genes revealed the presence of a highly conserved region in the C-terminal of predicted protein sequences, designated the SOC1 motif. Phylogenetic analysis indicated that TrcMADS1 is at the basal position of the SOC1/TM3-like gene family. The TrcMADS1 mRNA was detected in both vegetative and reproductive organs by RT-PCR. Our results suggest that duplicated copies of SOC1/TM3-like gene evolved to become variously functionally specialized.

The cycloidea (CYC) gene controls floral symmetry in snapdragon (Antirrhinum majus). We investigated the evolution of CYC-like genes in some species of legumes that have zygomorphic flowers. Two to four CYC-like genes were isolated from a single species. The results of NJ and ML analyses indicate that CYC-like genes in legumes group into two monophyletic clades; one group consists of eight CYC-like genes (Clade 1) and the other contains three CYC-like genes and TB1 of maize (Clade 2). These phylogenetic trees and the Shimodaira-Hasegawa test suggest that Clade 1 is a sister of the original CYC group (Clade 3). Moreover, the result of the GeneTree analysis showed that the CYC-like genes experienced repeated duplication events during the evolution of legumes. We herein speculate as to the role of CYC-like genes in legumes and discuss the evolutionary processes that these genes have undergone.

Approximately one-fourth of Japan's native plant species are threatened with extinction. To conserve these species, it is critical to evaluate genetic diversity at species-level and population-level. Some factors, including population size and geographic distribution, are known to influence the population genetic diversity of wild plant species. This article briefly reviews the population genetic studies that have been conducted on wild threatened plants in Japan. A large population size or wide geographic distribution does not always lead to large genetic diversity, suggesting that historical factors such as speciation processes and population expansion often play more important roles in determining genetic diversity than the number of remnant individuals. The mating system of a species also affects genetic diversity; predominantly selfing species tend to have smaller genetic diversity than outcrossing congeners. Another issue of concern in the conservation genetics of wild plants in Japan is the genetic diversity of insular endemics, because Japan consists of many islands, and the insular flora contains many endemic and threatened species. Previous studies on endemic plants on the Bonin and the Ryukyu Islands are reviewed. Compared to the cases of the Bonin Islands or other oceanic islands, there is much larger genetic diversity in plants endemic to the Ryukyu Islands. This difference is probably the result of the differences in the geological history of these islands.

To examine the evolution of gynodioecy under biparental inbreeding, we developed a new theoretical model and tested it by estimating paramaeters incorporated in the model in a gynodioecious population ofChionographis japonica var.kurohimensis. The model and the results showed biparental inbreeding affects the evolution of gynodioecy, but the effect is very small.

Since Darwin’s observations on the biota of the Galapagos, the evolution of island plants has attracted the attention of many investigators (Carlquist, 1974). Adaptive radiation of organisms on oceanic islands continues to be one of the most interesting topics in evolutionary biology. Opportunities for studying evolution are excellent on islands because of the high levels of variation. The development of the theory of island biogeography has offered a basis for the study of the ecology and evolution of island biotas in relation to neighboring continents (MacArthur and Wilson, 1967; MacArthur, 1972). The theory predicts that the number of species on an island will decrease with distance from the mainland and that species with greater colonizing ability are more likely to establish on a given island. Plant species on islands may evolve through interactions with flora and fauna that are different from those on the nearby mainland.

Nuclear genes determine the vast range of phenotypes that are responsible for the adaptive abilities of organisms in nature. Nevertheless, the evolutionary processes that generate the structures and functions of nuclear genes are only now be coming understood. The aim of our study is to isolate the alcohol dehydrogenase (Adh) genes in two distantly related legumes, and use these sequences to examine the molecular evolutionary history of this nuclear gene. We isolated the expressed Adh genes from two species of legumes, Sophora flavescens Ait. and Wisteria floribunda DC., by a RT-PCR based approach and found a new Adh locus in addition to homologues of the Adh genes found previously in legumes. To examine the evolution of these genes, we compared the species and gene trees and found gene duplication of the Adh loci in the legumes occurred as an ancient event. This is the first report revealing that some legume species have at least two Adh gene loci belonging to separate clades. Phylogenetic analyses suggest that these genes resulted from relatively ancient duplication events.

Etude de l'effet a l'aide d'un modele numerique 1D ou le refroidissement advectif horizontal a ete parametrise au moyen de l'analyse du bilan de chaleur et du profil en loi de puissance, de la t de l'air. On trouve que le refroidissement nocturne dans le bassin (profondeur 500 m) est 15% en hiver et 25% en ete, plus eleve qu'en terrain plat. Il est 40% en hiver et 90% en ete, plus eleve qu'au sommet de la montagne ou des collines