Gao Chen

Phylogeography of Buddleja crispa (Buddlejaceae) and its correlation with drainage system evolution in southwestern China

UNLABELLEDnnnnPREMISE OF THE STUDYnSouthwestern China is an area of active tectonism and erosion, yielding a dynamic, deeply eroded landscape that is hypothesized to have influenced the genetic structure of the resident populations of plants and animals. However, few studies have been conducted to examine the influence of changing river channels, particularly in the Yarlung Tsangpo area, on genetic distributions in plants. We here examine the population structure of Buddleja crispa, a dominant element of the dry, warm/hot river-valley communities, seeking to delimit the current population genetic structure and its relation to past changes in the courses of the major rivers in this area. •nnnMETHODSnTwo chloroplast DNA fragments were used to estimate the genetic variation and phylogeographic structure of the populations, and to infer nested clades, of the species. •nnnKEY RESULTSnWe detected low intrapopulational haplotype diversity and higher overall population haplotype diversity (h(S) = 0.085, h(T) = 0.781). Molecular variance was mainly observed between groups (81.42%). Robust population genetic structure were detected by AMOVA (F(ST) = 0.967), coinciding with three nested clades (identified by NCPA) and five phylo-groups linked with paleo-drainage systems (identified by SAMOVA). No support for extensive spatial or demographical expansion was obtained. •nnnCONCLUSIONSnA general pattern of genetic isolation by vicariance was inferred, and detected disjunct patterns strongly indicate that currently discontinuous drainage systems were historically linked. Most importantly, population subdivisions and genetic variation perfectly reflect the putative Paleo-Red-River drainage pattern, and Yarlung Tsangpo populations are closely related to Central Yunnan Plateau populations, indicating that they were previously connected by ancient river courses. Divergence times between these river systems estimated by molecular dating (in the Pleistocene) agree with previous findings.

Rescuing Magnolia sinica (Magnoliaceae), a Critically Endangered species endemic to Yunnan, China

Magnolia sinica, a Critically Endangered tree endemic to Yunnan, China, is one of the 20 plant species with extremely small populations approved by the Yunnan government for urgent rescue action before 2015 Information on the geographical distribution and population size of this species had not previously been reported, hindering effective conservation. We therefore carried out a survey of the literature and of herbarium specimens, followed by a detailed field survey and morphological measurements and observations of surviving individuals. We located 52 individuals in the wild, in eight localities. Two distinguishing morphological characters (tepal colour and tepal number) were revised based on observations of all remaining wild individuals that produced flowers and on one 30-year-old flowering plant in Kunming Botanical Garden. The survival rate of individuals propagated from seed for ex situ conservation at the Garden was 100 % over. years; of 100 individuals transplanted to each of two reinforcement sites, 20 and 18, respectively, were alive after. years. We propose two groups of measures to protect M. sinica: (1) in situ conservation, population monitoring, and public engagement, and (2) ex situ conservation with reinforcement or reintroduction.

Morphological characteristics of leaf epidermis and size variation of leaf, flower and fruit in different ploidy levels in Buddleja macrostachya (Buddlejaceae)

Abstractu2003 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 of B. macrostachya. In general, flower and fruit length, absolute leaf size, and stomatal length increased 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 hexaploid from dodecaploid cytotypes either in the field or in herbarium specimens.

Variation in floral characters, particularly floral scent, in sapromyophilous Stemona species

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.

Comparison of floral properties and breeding system in dimorphic Buddleja delavayi (Scrophulariaceae)

In this study, floral color, scent composition and emission rate, nectar property, pollinators, and breeding system of dimorphic Buddleja delavayi Gagnep. were investigated. Flower color of B. delavayi was determined using a standard color chart and spectrophotometer, and two distinct color polymorphisms were observed having purple or white flowers. Floral scents of B. delavayi were collected using dynamic headspace adsorption and identified with coupled gas chromatography and mass spectrometry. In total, 28 compounds were identified from the flowers of B. delavayi. The identified scents were divided into three chemical classes based on their biosynthetic origin: terpenes, fatty acid derivatives, and benzenoids. The scent profiles in all individuals were dominated by a few components, such as lilac aldehyde and alcohol, 4‐oxoisophorone, benaldehyde, and oxoisophorone oxide. Floral scent composition (benzenoids and terpenes) showed a significant difference between white and purple flower morphs. Flower color–flower scent associations in B. delavayi were identified with two distinct scent profiles in the two color phenotypes. The studies of other floral characteristics (nectar, floral visitors, breeding system, and fruit set) indicated that floral scent emission rate, nectar volume, visitor visitation frequency, and natural fruit set were not significantly different between the two flower color morphs. Bagging experiments revealed that seed production of B. delavayi is dependent mainly on honeybee Apis cerana. Lastly, this study implies that dimorphic floral color in B. delavayi may have been maintained by floral visitors and nectar guide color.

Phoretic mite Neocypholaelaps indica Evans infests inflorescences of Pachysandra axillari Franch. and its pollinators, Apis cerana Fabricius

In this study, we report that the phoretic flower mite Neocypholaelaps indica can infest flowers of Pachysandra axillaris and Apis cerana in Yunnan, China. We suggest that beekeepers, researchers and regulators should be aware of this species to regulate its potential harm to beekeeping and output of crops in China.

Floral characteristics and pollination ecology of Manglietia ventii (Magnoliaceae), a plant species with extremely small populations (PSESP) endemic to South Yunnan of China

Manglietia ventii is a highly endangered plant species endemic to Yunnan province in China, where there are only five known small populations. Despite abundant flowering there is very low fruit and seed set, and very few seedlings in natural populations, indicating problems with reproduction. The causes of low fecundity in M. ventii are not known, largely because of insufficient knowledge of the species pollination ecology and breeding system. We conducted observations and pollination experiments, and analyzed floral scents to understand the pollinator–plant interactions and the role of floral scent in this relationship, as well as the species breeding system. Like the majority of Magnoliaceae, M. ventii has protogynous and nocturnal flowers that emit a strong fragrance over two consecutive evenings. There is a closing period (the pre-staminate stage) during the process of anthesis of a flower, and we characterize the key flowering process as an “open-close-reopen” flowering rhythm with five distinct floral stages observed throughout the floral period of this species: pre-pistillate, pistillate, pre-staminate, staminate, and post-staminate. Flowers are in the pistillate stage during the first night of anthesis and enter the staminate stage the next night. During anthesis, floral scent emission occurs in the pistillate and staminate stages. The effective pollinators were weevils (Sitophilus sp.) and beetles (Anomala sp.), while the role of Rove beetles (Aleochara sp.) and thrips (Thrips sp.) in pollination of M. ventii appears to be minor or absent. The major chemical compounds of the floral scents were Limonene, β-Pinene, α-Pinene, 1,8-Cineole, Methyl-2-methylbutyrate, p-Cymene, Methyl-3-methyl-2-butenoate and 2-Methoxy-2-methyl-3-buten, and the relative proportions of these compounds varied between the pistillate and staminate stages. Production of these chemicals coincided with flower visitation by weevils and beetles. The results of pollination experiments suggest that M. ventii is pollinator-dependent, and low seed set in natural populations is a result of insufficient pollen deposition. Thus, conservation of the species should focus on improving pollination service through the introduction of genetically variable individuals and increase in density of reproducing trees.

The role of botanical gardens in scientific research, conservation, and citizen science

Plant diversity is currently being lost at an unprecedented rate, resulting in an associated decrease in ecosystem services. About a third of the worlds vascular plant species face the threat of extinction due to a variety of devastating activities, including, over-harvesting and over exploitation, destructive agricultural and forestry practices, urbanization, environmental pollution, land-use changes, exotic invasive species, global climate change, and more. We therefore need to increase our efforts to develop integrative conservation approaches for plant species conservation. Botanical gardens devote their resources to the study and conservation of plants, as well as making the worlds plant species diversity known to the public. These gardens also play a central role in meeting human needs and providing well-being. In this minireview, a framework for the integrated missions of botanical gardens, including scientific research, in/ex situ conservation, plant resource utilization, and citizen science are cataloged. By reviewing the history of the development of Kunming Botanical Garden, we illustrate successful species conservation approaches (among others, projects involving Camellia, Rhododendron, Magnolia, Begonia, Allium, Nepenthes, medicinal plants, ornamental plants, and Plant Species with Extreme Small Populations), as well as citizen science, and scientific research at Kunming Botanical Garden over the past 80 years. We emphasize that Kunming Botanical Garden focuses largely on the ex situ conservation of plants from Southwest China, especially those endangered, endemic, and economically important plant species native to the Yunnan Plateau and the southern Hengduan Mountains. We also discuss the future challenges and responsibilities of botanical gardens in a changing world, including: the negative effects of outbreeding and/or inbreeding depression; promoting awareness, study, and conservation of plant species diversity; accelerating global access to information about plant diversity; increasing capacity building and training activities. We hope this minireview can promote understanding of the role of botanical gardens.

Conserving threatened widespread species: a case study using a traditional medicinal plant in Asia

Overharvesting and loss of habitat arising from human activities are the most important threats to plants and animals. Conservation efforts targeting medicinal plant species usually focus on endemic, economic and endangered taxa, typically Plant Species with Extremely Small Populations (PSESP) under high extinction risk. However, comparatively little attention has been focused on traditional medicinal plants with widespread distribution, although some of these species, where the whole plant or the tubers are raw materials for medicines, may be on the edge of local extinction. In this study, we appeal to conservationists to pay close attention to threatened widespread species. To this end, a traditional medicinal plant, Stemona tuberosa, which has a distribution that covers more than ten countries in Asia, is studied in detail. The results suggest that destructive overharvesting of the underground tuberous roots of S. tuberosa is the key threat to this species. In addition, pollination limitation, loss of potential seed dispersers, habitat loss, and a scattered distribution pattern may further reduce the survival chances of S. tuberosa. Through multidisciplinary conservation efforts conducted by researchers and local resident, we witnessed the preliminary recovery of S. tuberosa in locations where it has been reintroduced. We think that threatened widespread species should not be overlooked in the field of conservation. Local participation in natural resource management may help to make resources more relevant locally and hence sustainable in remote regions. We suggest that developing multi-stakeholder coalitions should be encouraged to save threatened medicinal plant species in underdeveloped areas.