气候变化下中国八种梧桐属树种潜在适生区模拟

中国梧桐属（Firmiana）在世界梧桐属中占比较大,且除梧桐外其余种均为中国特有且分布范围狭窄的植物种,灭绝风险大,研究气候变化对中国梧桐属树种的影响对于维护生物多样性具有重要的意义。结合多时期第六次国际气候耦合模式比较计划（CMIP6）气候变量数据和中国八种梧桐属树种的分布数据,基于R语言kuenm程序包优化的最大熵（Maxent）模型模拟分析中国八种梧桐属树种在多尺度下的潜在适生区,得出梧桐属最适宜的模拟尺度、潜在适生区的面积变化和迁移方向、梧桐属多样性保护关键区域及保护空缺。结果表明：（1）梧桐属最适宜的模拟尺度为亚洲;（2） Maxent模型的接收者操作特征曲线下面积（AUC）值均大于0.9,表明模型对梧桐属潜在适生区预测结果具有较高准确度;（3）气候变化影响下除云南梧桐（Firmiana major）外其它树种的潜在适生区都将在未来有所扩大;（4）中国八种梧桐属树种潜在适生区迁移方向主要为东西向,南北向大跨度迁移较少,纬度变化不大;（5）丹霞梧桐（Firmiana danxiaensis）的稳定潜在适生区最小;（6）中国梧桐属多样性保护关键区域主要分布于广西壮族自治区及云南、广东、海南等省区;（7）中国梧桐属多样性保护空缺区域主要分布于广西壮族自治区中部及海南省北部;（8）梧桐属多样性保护关键区域正在为人造地表所侵蚀。研究分析气候变化对中国八种梧桐属树种的影响及其潜在适生区变化、中国梧桐属多样性保护状态,可为中国梧桐属建立多样性保护廊道提供相关建议,为制定多样性保护规划及相应措施提供参考。     

Firmiana (Malvaceae: Sterculioideae) fruits from the Upper Miocene of Yunnan,Southwest China

A new species of Firmiana Marsili is recognized and described based on capsules from the Late Miocene Lincang flora of Yunnan, China. Firmiana yunnanensis nov. sp. is represented by opened, dehiscent, membranous follicles with a weak, sinuous midvein, obtuse secondary veins and thick marginal vein. The follicles conform in shape and venation with those of extant species of Firmiana, a genus now distributed in eastern Africa, Indo-Malaysia, and eastern and southeastern Asia. This fossil species occurred within the native distribution of extant Firmiana species. It provides new information on fossil history, paleoecology, as well as on the plant diversity of the Lincang flora.     

Genetic variability of the narrow endemic Rhamnus persicifolia Moris (Rhamnaceae) and its implications for conservation

Rhamnus persicifolia Moris is an endemic small tree belonging to the Rhamnus cathartica group, growing along mountainous streams of Central-Eastern Sardinia (Italy). ISSR markers were used to detect the genetic diversity within and among six populations representative of the species distribution range. In spite of the limited distribution of this endemic taxon, fairly high levels of genetic diversity were detected. Percentage of polymorphic bands (PPB), gene diversity (H_S and H_T) and Shannon information measure (Sh) were calculated both at population (PPB = 30.70%, H_S = 0.1105, Sh = 0.1646) and at species level (PPB = 68.42%, H_T = 0.2066, Sh = 0.3139).The existence of a spatial distribution of genetic diversity in R. persicifolia was revealed by a low gene flow, a fairly high level of genetic differentiation (G_ST = 0.4583) among populations and a positive correlation between genetic and geographic distances (Mantel test, r = 0.71, p = 0.016). The spatial genetic structure was also confirmed with BAPS analysis. Our results show that a certain level of isolation by distance and sex-ratio bias may explain the distribution of genetic diversity among populations.Conservation measures are suggested on the basis of the genetic diversity detected, by implementing an integrated in situ and ex situ conservation program for each population, in order to ensure effective protection for this endemic species.     

广东报春苣苔属一新种——黄进报春苣苔

该文报道了在广东丹霞山发现的报春苣苔属一新种——黄进报春苣苔(Primulina huangjiniana),并对其进行了描述。该新种与同属物种短序报春苣苔(P. depressa)最为相似,但两者在形态特征上能够很好地区别:黄进报春苣苔具有更短的、长2.5～6 mm的苞片(vs. 短序报春苣苔具有长15～30 mm的苞片,顺序下同); 花萼裂片等长(vs. 不等长),花丝基部附近膝状突起,中部以上具腺毛(vs. 于中部膝状突起且无毛); 柱头倒三角形,深2裂成2线形裂片(vs. 片状,稍2浅裂,裂片为三角形),侧膜胎座(vs. 中轴胎座)。加上该新种在内,丹霞山目前共记录有6种报春苣苔属植物,其中丹霞小花苣苔(P. danxiaensis)和该新种均为丹霞地貌特有植物。黄进报春苣苔目前在丹霞山的两个地方有发现,成年植株不超过200株,根据IUCN红色名录标准,属于极危种。     

Genetic diversity of the endangered Chinese endemic plant Monimopetalum chinense revealed by amplified fragment length polymorphism (AFLP)

Monimopetalum chinense Rehd. is an endangered woody vine endemic to eastern China. Using amplified fragment length polymorphism (AFLP) markers, we examined levels of genetic variation within and among eleven populations located across the species’ distribution. Although modest levels of heterozygosity were detected, other measures of genetic diversity registered relatively high levels of variability, both at the species level (P = 91.0%, H_E = 0.232, I_S = 0.365) and at the population level (P = 53.0%, H_E = 0.155, I_S = 0.239). Populations also exhibited high levels of genetic differentiation (Nei’s genetic diversity analysis, G_ST = 0.330), corresponding to isolation-by-distance and hierarchical population structure. These results indicate that, despite low levels of gene flow, populations of M. chinense still harbor substantial amounts of genetic diversity. Management plans for the species should include measures that ensure genetic diversity remains high within and among extant populations.     

The impact of climate change on the distribution of rare and endangered tree Firmiana kwangsiensis using the Maxent modeling

The upsurge in anthropogenic climate change has accelerated the habitat loss and fragmentation of wild animals and plants. The rare and endangered plants are important biodiversity elements. However, the lack of comprehensive and reliable information on the spatial distribution of these organisms has hampered holistic and efficient conservation management measures. We explored the consequences of climate change on the geographical distribution of Firmiana kwangsiensis (Malvaceae), an endangered species, to provide a reference for conservation, introduction, and cultivation of this species in new ecological zones. Modeling of the potential distribution of F. kwangsiensis under the current and two future climate scenarios in maximum entropy was performed based on 30 occurrence records and 27 environmental variables of the plant. We found that precipitation‐associated and temperature‐associated variables limited the potentially suitable habitats for F. kwangsiensis. Our model predicted 259,504 km² of F. kwangsiensis habitat based on 25 percentile thresholds. However, the high suitable habitat for F. kwangsiensis is only about 41,027 km². F. kwangsiensis is most distributed in Guangxi''s protected areas. However, the existing reserves are only 2.7% of the total suitable habitat and 4.2% of the high suitable habitat for the plant, lower than the average protection area in Guangxi (7.2%). This means the current protected areas network is insufficient, underlining the need for alternative conservation mechanisms to protect the plant habitat. Our findings will help identify additional F. kwangsiensis localities and potential habitats and inform the development and implementation of conservation, management, and cultivation practices of such rare tree species.     

Identification,development, and application of 12 polymorphic EST-SSR markers for an endemic Chinese walnut (Juglans cathayensis L.) using next-generation sequencing technology

The Chinese walnut (Juglans cathayensis L.), valued for both its nut and wood, is an ecologically important tree species endemic temperate southern China. Investigation of the genetic diversity of Chinese walnut has been limited to natural population genetics and genetic germplasm resources. Here, we describe the development of 12 polymorphic microsatellite markers using next-generation sequencing to screen 96 Chinese walnut individuals collected from 11 natural populations. The number of alleles per locus ranged from 5 to 12. The observed heterozygosity (0.288–0.748) overlapped well with the expected heterozygosity (0.337–0.751). This species has high genetic diversity and gene flow among different populations (F_ST = 0.075, Nm = 3.088). These markers will be useful for future studies on population genetic structure, evolutionary ecology, and genetic breeding of this walnut tree or other Juglans species.     

Isolation and characterization of microsatellite markers for Cycas hainanensis C. J. Chen (Cycadaceae)

Cycas hainanensis is an endangered cycad species endemic to Hainan Island, China. To enrich our scientific conservation for this species, we developed eight microsatellite markers using repetitive DNA enriched libraries. The number of alleles per microsatellite locus varied from 8 to 17. The expected (H _E ) and observed (H _O ) heterozygosities varied from 0.4754 to 0.8846 and from 0.3636 to 0.9600, respectively. These markers will be employed to determine whether the ex situ C. hainanensis individuals in Sourh China Botanical Garden capture a representative portion of genetic diversity of the wild populations.     

Genetic diversity of the endangered Chinese endemic herb Dayaoshania cotinifolia (Gesneriaceae) revealed by simple sequence repeat (SSR) markers

Dayaoshania cotinifolia W.T. Wang is a critically endangered perennial herb endemic to southern China. Simple sequence repeat (SSR) markers were employed to assess genetic diversity in two populations of D. cotinifolia. Eight primer pairs generated a total of 36 alleles, with a mean of 4.5 alleles per locus. The expected heterozygosity (H_e = 0.416) and observed heterozygosity (H_o = 0.508) indicated a moderate level of genetic diversity, though the genetic differentiation between the populations was low (F_st = 0.014), a result that was supported by a higher gene flow (N_m = 18.000). No severe bottleneck effect was detected in the two populations. Thus, the endangered status of this species is most likely due to anthropologic effects rather than a lack of genetic diversity. In situ conservation strategies should be promoted, and the sizes of the populations should be increased through artificial breeding.     

Genetic diversity within and among populations of the endangered and endemic species Primula merrilliana in China

Primula merrilliana Schltr. is an endangered and narrowly-distributed endemic species of southern Anhui Province in China. In this study, the level of genetic variation and the pattern of genetic structure in six natural populations of P. merrilliana were assessed by using ISSR (inter-simple sequence repeats) markers. Based on ten primers, 137 clear and reproducible DNA fragments were generated, of which 109 were polymorphic. The statistical results indicated that there was a relatively low genetic diversity within populations, and a high genetic differentiation among populations (G_ST = 0.53, Φ_ST = 0.49). The level of population genetic diversity was correlated to habitat type and the gene flow (N_m) was low with only 0.45. The unexpected genetic structure of P. merrilliana may be explained by limited gene flow that was caused by habitat fragmentation and limited seeds and pollen dispersal ability, self-compatible breeding system and biennial life form.     

Allozyme diversity levels in two congeneric Dioon spp. (Zamiaceae, Cycadales) with contrasting rarities

Allozyme diversity and population genetic structure studies were conducted in populations of two Mexican cycad species occurring in adjacent and closely related biogeographic regions. We evaluated if rarity traits in Dioon caputoi, a micro-endemic species, and Dioon merolae, a regional endemic with a wider distribution, influence levels of genetic diversity in different ways. We also explored if genetic structure differs in these species, considering that they have similar population histories. Our results indicate that D. caputoi harbors lower levels of genetic diversity and allelic richness (H _E = 0.358, P = 76.9, A _r = 1.86) than D. merolae (H _E = 0.446, P = 92.3, A _r = 2). However, genetic structure does not differ between the two species despite their contrasting geographic distributions (F _ST = 0.06 vs. 0.07; D. caputoi and D. merolae, respectively). The comparison of population genetic structure information with historical and geographical aspects of the populations suggests that the rarity of D. caputoi might be due to relatively recent local ecological factors.     

Isolation and characterization of twelve polymorphic microsatellite markers in the endangered Hopea hainanensis (Dipterocarpaceae)

Microsatellite markers were isolated and characterized for Hopea hainanensis Merrill & Chun, an endangered tree species with scattered distribution in Hainan Island and northern Vietnam. Twenty‐six microsatellite markers were developed based on next‐generation sequencing data and were genotyped by capillary electrophoresis on an ABI 3730xl DNA Analyzer. Twelve markers were found to be polymorphic in H. hainanensis. GENODIVE analyses indicated that the number of alleles ranged from 2 to 6 per locus, and the observed and expected heterozygosity varied from 0 to 0.755 and from 0.259 to 0.779, respectively. Primer transferability was tested with Hopea chinensis Hand.‐Mazz. and Hopea reticulata Tardieu, in which 3 and 7 microsatellite markers were found to be polymorphic, separately. The results showed that H. reticulata and H. hainanensis had similar levels of genetic diversity. A neighbor joining dendrogram clustered all individuals into two major groups, one of which was exclusively constituted by H. hainanensis, while the other consisted of two subgroups, corresponding to H. reticulata and H. chinensis, respectively. The 12 polymorphic microsatellite markers could be applied to study genetic diversity, population differentiation, mating system, and fine‐scale spatial genetic structures of H. hainanensis as well as its close relatives, facilitating the conservation and restoration of these endangered but valuable Hopea species.     

Genetic diversity in Mentha cervina based on morphological traits,essential oils profile and ISSRs markers

Morphological, phytochemical and genetic differences were studied to evaluate the level and distribution of diversity in twelve populations of the Portuguese endangered medicinal plant Mentha cervina L. Morphological variation was correlated with ecological conditions at the site of origin. Pulegone was the major essential oils compound in all of the populations collected at full flowering (68–83%), in different growing conditions (51–82%), and for all the developmental stages studied (47–82%). Although clusters were defined, the analysis revealed a high chemical correlation among all populations (S_corr ≥ 0.95%). Inter-simple sequence repeats markers were used to assess the population structure and genetic variation. Populations exhibited a relatively low genetic diversity (PPB = 14.3–64.6%, H_e = 0.051–0.222, I = 0.076–0.332), with high structuring between them (G_ST = 0.51). However, the genetic diversity at species level was relatively high (PPB = 97.7%; H_e = 0.320). The levels and patterns of genetic diversity were assumed to result largely from a combination of evolutionary history and its unique biological traits, such as breeding system, clonal growth, low capacity of dispersion and habitat fragmentation. The relatively low genetic diversity in the populations analyzed indicates that the maintenance of their evolutionary potential is at risk if population sizes are maintained and if there is no protection of the habitats.     

Genetic diversity and population structure of endangered endemic Paeonia jishanensis in China and conservation implications

Paeonia jishanensis, one of the most important ancestral species of cultivated tree peonies, is an endangered ornamental and medicinal plant endemic to China. A total of 236 individuals of P. jishanensis from 10 extant populations were analysed using 21 EST-SSR markers to assess their genetic diversity and population structure. Moderate genetic diversity levels (H_E = 0.340) and high genetic differentiation among populations (F_ST = 0.335) were revealed. Combining the results of STRUCTURE, PCoA and neighbour-joining analyses, the 10 populations were divided into four genetic groups that were significantly related to their geographical origins, which was further supported by hierarchical AMOVA showing the highest variation of 17.9% among groups. The Mantel test showed a significant positive correlation between genetic distance and geographic distance among populations (r = 0.873, P < 0.0001). The genetic structure of P. jishanensis may be due to limited gene flow hindered by vicariance and its breeding system: facultative vegetative reproduction. This study carries significant implications for the conservation and utilization of this endangered species.     

湖南丹霞地貌区的苔藓植物多样性

丹霞地貌是一种特殊的红层地貌,拥有独特的植被和植物区系组成。苔藓植物在丹霞地貌植被演替中具有重要的生态意义,但其基本的种类组成和分布却不清楚。通过野外考察和标本鉴定,共发现湖南丹霞地貌区苔藓植物53科96属174种(包括变种和亚种),其中苔类植物21科24属36种,藓类植物32科72属138种,其中台湾曲柄藓(Campylopus taiwanensis)、芒尖毛口藓(Trichostomum zanderi)、小火藓(Schlotheimia pungens)、中华细枝藓(Lindergiasinensis)、疏叶叶苔(Jungermannia laxifolia)和刺叶拟蒴囊苔(Saccogynidium irregularispinosum)等6种为中国特有种;铜绿净口藓(Gymnostomum aeruginosum)、稀枝钱苔(Riccia huebeneriana)、羽枝片叶苔(Riccardia multifida)等30个种为湖南新记录种。在174种中,稀有种为87种,如梨蒴珠藓(Bartramia pomiformis)、小火藓、毛枝藓(Pilotrichopsisdentata)等,这些种大多生态幅狭窄,对生境要求较苛刻,常见种(22种)和非常常见种(30种)共52种,多为生境广泛种或世界广布种,如地钱(Marchantia polymorpha)等。文中还提供了详细的湖南丹霞地貌苔藓名录及其凭证标本信息,并建议优先保护崀山无底洞和万佛山三十六湾两个苔藓丰富的小区。     

Genetic diversity of Astragalus nitidiflorus, a critically endangered endemic of SE Spain,and implications for its conservation

Inter-simple sequence repeats (ISSR) markers were used to assess the genetic diversity and population structure in five populations of Astragalus nitidiflorus, a critically endangered species endemic to southeast Spain. Eight primers amplified 78 bands with 40 (51.3%) being polymorphic. Statistical results indicated a low genetic diversity at the population and species level, with percentages of polymorphic bands (PPB) ranging from 28.2 to 37.2% (an average of 31.8%), and means of gene diversity (H_E) of 0.129 and 0.171 respectively. The Shannon’s index (SI) ranged from 0.160 to 0.214 at the population level and was 0.260 at the species level. A low level of genetic differentiation among populations was detected, based on the Shannon’s information index (0.297), the coefficient of genetic differentiation between populations (G_ST = 0.2418) and AMOVA analysis (Φ_ST = 0.255). The estimated gene flow (Nm) was 0.789. The high genetic connectivity found among populations of A. nitidiflorus is an evidence of a recent habitat fragmentation. In addition, a bottleneck event in the past has been revealed, with a subsequent reduction of population size and a loss of genetic variation. Based on these results, the conservation strategy of A. nitidiflorus was proposed.     

湖南丹霞地貌区蕨类植物多样性

丹霞地貌是有别于石灰岩地貌和花岗岩地貌的特殊地貌类型,发育着较为独特的植被类型和植物区系。我们于2007-2010年间对湖南新宁崀山、茶陵浣溪、平江石牛寨、资兴程江口、浏阳达浒、通道万佛山、沅陵五强溪夸父山、溆浦思蒙等地丹霞地貌的蕨类植物进行了广泛调查,报道了湖南丹霞地貌区蕨类植物31科66属183种的详细名录。其中,无腺姬蕨(Hypolepis polypodioides)、隐囊蕨(Notholaena hirsuta)、仙霞铁线蕨(Adiantum juxtapo-situm)、百山祖短肠蕨(Allantodia baishanzuensis)、肉质短肠蕨(A.succulenta)、骨碎补铁角蕨(Asplenium ritoense)、钝齿耳蕨(Polystichum deltodon var.henryi)、无盖耳蕨(P.gymnocarpium)、单羽耳蕨(P.simplicipinnum)、二型肋毛蕨(Ctenitis dingnanensis)等9种为湖南新记录种。湖南丹霞地貌的蕨类植物种类组成主要有鳞毛蕨科、蹄盖蕨科、水龙骨科、金星蕨科、卷柏科、铁角蕨科等较大科及鳞毛蕨属(Dryopteris)、卷柏属(Selaginella)、铁角蕨属(Asplenium)、短肠蕨属(Allantodia)和凤尾蕨属(Pteris)等较大属。生态适应特点分析表明丹霞地貌既有喜钙质土的种类,也有喜酸性土的种类,仙霞铁线蕨和无盖耳蕨可能是丹霞地貌的特有植物,因而具有石灰岩地貌蕨类植物区系和花岗岩地貌蕨类植物区系之间的过渡性特点。建议将垫状卷柏(Selaginella pulvinata)、福建观音座莲(Angiopterisfokiensis)、仙霞铁线蕨、骨碎补铁角蕨、鞭叶蕨(Cyrtomidictyum lepidocaulon)、无盖耳蕨等种类列为丹霞地貌蕨类植物中的优先保护种类,将通道万佛山三十六湾、湖南沅陵夸父山列为丹霞地貌蕨类植物的优先保护地区。     

Host-associated genetic differentiation in rice grasshopper, Oxya japonica, on wild vs. cultivated rice

Rice grasshopper, Oxya japonica, is one of the most important pests in south China, mainly inhabiting fields of wild rice (Oryza rufipogon) and cultivated rice (Oryza sativa). In this study, we used AFLP marker to investigate the genetic diversity and population structure of rice grasshoppers collected from south China, with emphasis on testing the hypothesis that there was significant genetic differentiation among grasshopper populations associated with different hosts (i.e. wild vs. cultivated rice). Seven populations consisting of 104 individuals were sampled from Hainan Island and the mainland of south China. Eight primer combinations produced 564 reliable bands, of which 563 were polymorphic. O. japonica showed considerable genetic variation at population level, with gene diversity (H_E) ranging from 0.1103 to 0.2035. Genetic diversity were studied on seven populations, and generally three populations from wild rice had higher levels of genetic diversity (H_E = 0.1635) than the other four populations feeding on cultivated rice (H_E = 0.1327). We observed high population differentiation, with F_st ranging from 0.4172 to 0.7652 among the seven populations. However, Mantel test detected no significant correlation between genetic distance and geographical distance (r = 0.3541; p = 0.0689). By contrast, we found significant genetic differentiation between groups collected from different hosts. These data suggested that the anthropogenic activity in cultivated rice fields (i.e. pesticides, fertilization and cultivation) could have played an important role in shaping the genetic structure of O. japonica.     

Genetic diversity of four new species related to southwestern Sichuan buckwheats as revealed by karyotype,ISSR and allozyme characterization

The genetic diversity of four new species related to southwestern Sichuan buckwheats was examined using karyotypes, allozymes and intersimple sequence repeats (ISSR). Karyotype analysis showed that Fagopyrum wenchuanense, F. qiangcai and F. pugense are diploid (2n = 2x = 16) while F. crispatofolium is tetraploid (2n = 4x = 32). The karyotype evolutionary trend of buckwheat indicated that F. crispatofolium, F. gracilipes var. odontopterum and F. gracilipes seemed to be more advanced than F. wenchuanense, F. qiangcai, F. pugense, F. esculentum, F. cymosum and F. tataricumare. Three polymorphic enzyme systems were used for the examination of variation, including peroxidase, esterase and superoxide dismutase. Consistent banding patterns were obtained for esterase and superoxide dismutase, while peroxidase produced a large number of sharp bands. A total of 18 ISSR primers were selected for the analysis and showed high variations among the species. Allozymes and ISSR markers were utilized to estimate the genetic distance among accessions and to draw phylogenetic trees. Our data provide evidence of a high degree of genetic diversity among southwestern Sichuan buckwheats. In addition, both cultivars and wild types showed a high degree of divergence suggesting a complex domestication process in this crop. This study provides a better understanding of evolutionary mechanisms and genetic relationships in four new species of buckwheat.