Several conservation programs have been started for the critically endangered Sichou oak(Quercus sichourensis) since 2007.These programs include detailed field investigations,seedling cultivation and research on the f...Several conservation programs have been started for the critically endangered Sichou oak(Quercus sichourensis) since 2007.These programs include detailed field investigations,seedling cultivation and research on the fruit biology of the species.In this study,we first report on the five mature individual trees found in our 9-year field investigation.Thus far,a total of 10 mature individuals have been recorded.All Q.sichourensis trees are healthy and most produce healthy acorns.Acorns of Q.sichourensis are large with dry masses of 8.0-14.0 g.These acorns had high moisture contents at collection and died shortly after(7-28 d) when dried with silica gel.Characteristics of Q,sichourensis acorns varied between populations.Compared with the acorns from Funing,the acorns collected from Ceheng were bigger,more viable(germination percentage was up to 96%),less sensitive to desiccation,and germinated faster.Q.sichourensis occurs in regions with a distinct 5-6 month dry season.Habitat degradation is largely responsible for the rareness of Quercus sichorensis,but desiccation sensitivity of the acorns may also limit the regeneration of the species and potentially lead to its continued rareness.As a species with extremely small populations(PSESP),Q.sichourensis is facing high risk of extinction and should be defined as a Critically Endangered species in the global IUCN Red List.展开更多
Hibiscus aridicola is an endangered ornamental shrub of the family Malvaceae that is endemic to the dryhot valleys of Jinsha River in southwestern China.This species is a typical plant species with extremely small pop...Hibiscus aridicola is an endangered ornamental shrub of the family Malvaceae that is endemic to the dryhot valleys of Jinsha River in southwestern China.This species is a typical plant species with extremely small populations(PSESP).To support and monitor future conservation,develop management measures,and genotype this species,we performed extensive field studies together with genetic analyses.Specifically,we screened eleven microsatellite loci of 69 individuals of H.aridicola from four accessions.The population genetics analyses indicated that H.aridicola possesses high genetic diversity at both the population(0.6962-0.7293)and species level(0.7837)compared to other endemic/endangered species in China.The low differentiation of populations(Fst=0.0971)and the high gene flow between populations of H.aridicola(Nm=2.3236)could be due to its distribution along rivers in the hot-valleys of the Jinsha River and the wind-mediated dispersal of its seeds.Furthermore,the genetic diversity of H.aridicola is slightly positively correlated with geographic distance.Two populations are undergoing a genetic bottleneck,and require more specific attention from conservationists.Additionally,our analyses of the population genetics of H.aridicola demonstrate that the declines in populations are not the result of the internal genetics of these populations but due to external human activities over the past decades.展开更多
Buddleja macrostachya (Buddlejaceae) is a widespread shrub native to the Sino-Himalayan mountains and beyond. It has been found to occur at two ploidy levels, hexaploid, 2n=6x=114 and dodecaploid, 2n= 12x=228. To de...Buddleja macrostachya (Buddlejaceae) is a widespread shrub native to the Sino-Himalayan mountains and beyond. It has been found to occur at two ploidy levels, hexaploid, 2n=6x=114 and dodecaploid, 2n= 12x=228. To determine if morphological characters might be used as indicators of ploidy levels, we measured floral and fruit length, relative and absolute leaf size, trichome density on both leaf surfaces, and stomatal density and length in different populations orB. macrostachya. In general, flower and fruit length, absolute leaf size, and stomatal length in,eased with an increase at ploidy level (P〈0.01), whereas adaxial cell and stomatal density decreased with an increase at ploidy level (P〈0.01). We found no conspicuous differences in relative leaf size (P〉0.05) in different populations. Other characters studied such as trichome type, cuticular membrane and ornamentation of stomata, cell and stomatal shape, and anticlinal wall pattern were quite constant in this species. Thus it appears that flower and fruit length, absolute leaf size, and stomatal frequency and length can be used to distinguish hexaptoid from dodecaploid cytotypes either in the field or in herbarium specimens.展开更多
Phylogenetic studies have increased in recent years,largely due to rapid developments in sequencing techniques (Tucker et al.,2017).However,molecular phylogenetic studies rely on collecting biomaterials,which limits t...Phylogenetic studies have increased in recent years,largely due to rapid developments in sequencing techniques (Tucker et al.,2017).However,molecular phylogenetic studies rely on collecting biomaterials,which limits their applicability to many,especially small,rare plants,or inaccessible plants.Recently.展开更多
Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four po...Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four populations of Stemona tuberosa from 2011–2016, we demonstrate that hornets are the primary seed dispersers of S. tuberosa and play an important role in "long-distance" seed dispersal in this species. Furthermore, some ant species act as secondary dispersers and may transport the seeds to safe sites.Hornets and ants provide complementary seed dispersal at different spatial scales. This unique example of insect-plant mutualism may be an underestimated but important strategy to ensure "long-distance" seed dispersal in other myrmecochorous plants.展开更多
Flowers or inflorescences often deploy various signals, including visual, olfactory, and gustatory cues,that can be detected by their pollinators. In many plants,these cues and their functions are poorly understood.De...Flowers or inflorescences often deploy various signals, including visual, olfactory, and gustatory cues,that can be detected by their pollinators. In many plants,these cues and their functions are poorly understood.Deciphering the interactions between floral cues and pollinators is crucial for analyzing the reproductive success of flowering plants. In this study, we examined the composition of the fetid floral scents produced by several Stemona species, including nine S. tuberosa populations from across China, using dynamic headspace adsorption, gas chromatography, and mass spectrometry techniques. We compared variations in floral phenotype,including floral longevity, nectar rewards, pollinator behavior, and flower length and color among the Stemona species. Of the 54 scent compounds identified,the major compounds include fetid dimethyl disulfide,dimethyl trisulfide, 1-pyrroline, butyric acid, p-cresol,isoamyl alcohol, and indole. We detected striking differentiation in floral scent at both the species and population level, and even within a population of plants with different colored flowers. Floral characteristics related to sapromyophily and deceptive pollination,including flower color mimicking livor mortis and a lack of nectar, were found in five Stemona species, indicating that Stemona is a typical sapromyophilous taxon. Species of this monocot genus might employ evolutionary tactics to exploit saprophilous flies for pollination.展开更多
基金supported by NSFCYunnan joint fund to support key projects (No. U1302262 and U1502231)
文摘Several conservation programs have been started for the critically endangered Sichou oak(Quercus sichourensis) since 2007.These programs include detailed field investigations,seedling cultivation and research on the fruit biology of the species.In this study,we first report on the five mature individual trees found in our 9-year field investigation.Thus far,a total of 10 mature individuals have been recorded.All Q.sichourensis trees are healthy and most produce healthy acorns.Acorns of Q.sichourensis are large with dry masses of 8.0-14.0 g.These acorns had high moisture contents at collection and died shortly after(7-28 d) when dried with silica gel.Characteristics of Q,sichourensis acorns varied between populations.Compared with the acorns from Funing,the acorns collected from Ceheng were bigger,more viable(germination percentage was up to 96%),less sensitive to desiccation,and germinated faster.Q.sichourensis occurs in regions with a distinct 5-6 month dry season.Habitat degradation is largely responsible for the rareness of Quercus sichorensis,but desiccation sensitivity of the acorns may also limit the regeneration of the species and potentially lead to its continued rareness.As a species with extremely small populations(PSESP),Q.sichourensis is facing high risk of extinction and should be defined as a Critically Endangered species in the global IUCN Red List.
基金Support for this study was provided through grants from the NSFC (National Natural Science Foundation of China)-Yunnan Joint Funds to support key projects (Grant No. U1302262, No. U1602264)Yunnan Science and Technology Innovation Team Program for PSESP (Plant Species with Extremely Small Populations) Conservation and Utilization (Grant No. 2019HC015)the Young Academic and Technical Leader Raising Foundation of Yunnan Province (Grant No. 2015HB091)
文摘Hibiscus aridicola is an endangered ornamental shrub of the family Malvaceae that is endemic to the dryhot valleys of Jinsha River in southwestern China.This species is a typical plant species with extremely small populations(PSESP).To support and monitor future conservation,develop management measures,and genotype this species,we performed extensive field studies together with genetic analyses.Specifically,we screened eleven microsatellite loci of 69 individuals of H.aridicola from four accessions.The population genetics analyses indicated that H.aridicola possesses high genetic diversity at both the population(0.6962-0.7293)and species level(0.7837)compared to other endemic/endangered species in China.The low differentiation of populations(Fst=0.0971)and the high gene flow between populations of H.aridicola(Nm=2.3236)could be due to its distribution along rivers in the hot-valleys of the Jinsha River and the wind-mediated dispersal of its seeds.Furthermore,the genetic diversity of H.aridicola is slightly positively correlated with geographic distance.Two populations are undergoing a genetic bottleneck,and require more specific attention from conservationists.Additionally,our analyses of the population genetics of H.aridicola demonstrate that the declines in populations are not the result of the internal genetics of these populations but due to external human activities over the past decades.
基金supported by grants-in-aid from the National Natural Science Foundation of China (NSFC 30625004,40771073)the Yunnan Natural Science Foundation(2008CC013)
文摘Buddleja macrostachya (Buddlejaceae) is a widespread shrub native to the Sino-Himalayan mountains and beyond. It has been found to occur at two ploidy levels, hexaploid, 2n=6x=114 and dodecaploid, 2n= 12x=228. To determine if morphological characters might be used as indicators of ploidy levels, we measured floral and fruit length, relative and absolute leaf size, trichome density on both leaf surfaces, and stomatal density and length in different populations orB. macrostachya. In general, flower and fruit length, absolute leaf size, and stomatal length in,eased with an increase at ploidy level (P〈0.01), whereas adaxial cell and stomatal density decreased with an increase at ploidy level (P〈0.01). We found no conspicuous differences in relative leaf size (P〉0.05) in different populations. Other characters studied such as trichome type, cuticular membrane and ornamentation of stomata, cell and stomatal shape, and anticlinal wall pattern were quite constant in this species. Thus it appears that flower and fruit length, absolute leaf size, and stomatal frequency and length can be used to distinguish hexaptoid from dodecaploid cytotypes either in the field or in herbarium specimens.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program (2019QZKK0502 to H.S.)National Natural Science Foundation of China (Grant No. 32001230 to LT.)the Science and Technology Basic Resources Investigation Program of China (Grant No.2017FY100100 to W.S.)。
文摘Phylogenetic studies have increased in recent years,largely due to rapid developments in sequencing techniques (Tucker et al.,2017).However,molecular phylogenetic studies rely on collecting biomaterials,which limits their applicability to many,especially small,rare plants,or inaccessible plants.Recently.
基金Support for this study was provided by grants from the NSFC-Yunnan joint fund to support key projects(U1602266)the National Natural Science Foundation of China(31670322)the Young Academic and Technical Leader Raising Foundation of Yunnan Province(2015HB091)to G.Chen
文摘Vespicochory, seed dispersal by hornets, is a rare seed dispersal mechanism in angiosperms and, to date, there are few records of this phenomenon.Through field investigations and behavioral assays conducted in four populations of Stemona tuberosa from 2011–2016, we demonstrate that hornets are the primary seed dispersers of S. tuberosa and play an important role in "long-distance" seed dispersal in this species. Furthermore, some ant species act as secondary dispersers and may transport the seeds to safe sites.Hornets and ants provide complementary seed dispersal at different spatial scales. This unique example of insect-plant mutualism may be an underestimated but important strategy to ensure "long-distance" seed dispersal in other myrmecochorous plants.
基金Support for this study was provided by grants from the NSFC-Yunnan joint fund to support key projects to G.Chen(U1602264)the National Natural Science Foundation of China(31670322)the Young Academic and Technical Leader Raising Foundation of Yunnan Province(2015HB091)to G.Chen
文摘Flowers or inflorescences often deploy various signals, including visual, olfactory, and gustatory cues,that can be detected by their pollinators. In many plants,these cues and their functions are poorly understood.Deciphering the interactions between floral cues and pollinators is crucial for analyzing the reproductive success of flowering plants. In this study, we examined the composition of the fetid floral scents produced by several Stemona species, including nine S. tuberosa populations from across China, using dynamic headspace adsorption, gas chromatography, and mass spectrometry techniques. We compared variations in floral phenotype,including floral longevity, nectar rewards, pollinator behavior, and flower length and color among the Stemona species. Of the 54 scent compounds identified,the major compounds include fetid dimethyl disulfide,dimethyl trisulfide, 1-pyrroline, butyric acid, p-cresol,isoamyl alcohol, and indole. We detected striking differentiation in floral scent at both the species and population level, and even within a population of plants with different colored flowers. Floral characteristics related to sapromyophily and deceptive pollination,including flower color mimicking livor mortis and a lack of nectar, were found in five Stemona species, indicating that Stemona is a typical sapromyophilous taxon. Species of this monocot genus might employ evolutionary tactics to exploit saprophilous flies for pollination.