Traditional knowledge and its transmission of wild edibles used by the Naxi in Baidi Village, northwest Yunnan province

BACKGROUND

The collection and consumption of wild edibles is an important part in livelihood strategies throughout the world. There is an urgent need to document and safeguard the wild food knowledge, especially in remote areas. The aims of this study are to accomplish detailed investigation of wild edibles used by the Naxi in Baidi village and evaluate them to identify innovative organic food products. Also, we aim to explore the characteristics of distribution and transmission of the traditional knowledge (TK) on wild edibles among the Naxi.

METHODS

Data was collected through a semi-structured interview of key informants above the age of 20 years, chosen carefully by a snowball sampling. The interviews were supplemented by free lists and participatory observation methods. Informants below 20 years were interviewed to test their knowledge of traditional practices. A quantitative index like Cultural Importance Index (CI) was used to evaluate the relative importance of the different wild edibles. Linear regression and t-test were performed to test variation in the TK among the informants of different age groups and genders.

RESULTS

Altogether 173 wild edible plant species belonging to 76 families and 139 genera were recorded in the study. Cardamine macrophylla, C. tangutorum and Eutrema yunnanense, have traditionally been consumed as an important supplement to the diet, particularly during food shortages as wild vegetables. The age was found to have a significant effect on TK, but there was no significant difference between male and female informant in knowledge abundance. The traditional food knowledge was dynamic and affected by social factors. Also, it was descending partly among younger generations in Baidi.

CONCLUSION

Baidi village is a prime example of a rapidly changing community where local traditions compete with modern ways of life. Overall, this study provides a deeper understanding of the Naxi peoples' knowledge on wild edibles. Some wild edibles might have an interesting dietary constituent, which need in-depth studies. Such detail studies can help to promote the market in one hand and protect TK in the other. Protecting TK from disappearing in succeeding generations is necessary, and understanding the dynamics of TK is one important solution to this dilemma.

Diversity of wetland plants used traditionally in China: a literature review

BACKGROUND

In comparison with terrestrial plants, those growing in wetlands have been rarely studied ethnobotanically, including in China, yet people living in or near wetlands can accumulate much knowledge of the uses of local wetland plants. A characteristic of wetlands, cutting across climatic zones, is that many species are widely distributed, providing opportunities for studying general patterns of knowledge of the uses of plants across extensive areas, in the present case China. There is urgency in undertaking such studies, given the rapid rates of loss of traditional knowledge of wetland plants as is now occurring.

METHODS

There have been very few studies specifically on the traditional knowledge of wetland plants in China. However, much information on such knowledge does exist, but dispersed through a wide body of literature that is not specifically ethnobotanical, such as regional Floras. We have undertaken an extensive study of such literature to determine which species of wetland plants have been used traditionally and the main factors influencing patterns shown by such knowledge. Quantitative techniques have been used to evaluate the relative usefulness of different types of wetland plants and regression analyses to determine the extent to which different quantitative indices give similar results.

RESULTS

350 wetland plant species, belonging to 66 families and 187 genera, were found to have been used traditionally in China for a wide range of purposes. The top ten families used, in terms of numbers of species, were Poaceae, Polygonaceae, Cyperaceae, Lamiaceae, Asteraceae, Ranunculaceae, Hydrocharitaceae, Potamogetonaceae, Fabaceae, and Brassicaceae, in total accounting for 58.6% of all species used. These families often dominate wetland vegetation in China. The three most widely used genera were Polygonum, Potamogeton and Cyperus. The main uses of wetlands plants, in terms of numbers of species, were for medicine, food, and forage. Three different ways of assigning an importance value to species (Relative Frequency of Citation RFC; Cultural Importance CI; Cultural Value Index CV) all gave similar results.

CONCLUSIONS

A diverse range of wetland plants, in terms of both taxonomic affiliation and type of use, have been used traditionally in China. Medicine, forage and food are the three most important categories of use, the plants providing basic resources used by local people in their everyday lives. Local availability is the main factor influencing which species are used. Quantitative indexes, especially Cultural Value Index, proved very useful for evaluating the usefulness of plants as recorded in the literature.

Comparative homegarden medical ethnobotany of Naxi healers and farmers in Northwestern Yunnan, China

BACKGROUND

Homegardens are ecologically and culturally important systems for cultivating medicinal plants for wellbeing by healers and farmers in Naxi communities of the Sino Himalayan region. The cultivation of medicinal plants in Naxi communities and associated ethnomedical knowledge base for maintaining and utilizing these resources is at risk with expanded commercialization of natural resources, development policies and rapid socio-economic change in China. Research is needed to understand the medicinal plant species maintained in Naxi homegardens, their use and contribution to community wellbeing, and how these practices and knowledge base varies between Naxi healers and farmers in order to develop plans for biodiversity conservation and preservation of ethnomedical practices. The main objective of this study is to document and compare medicinal plant species in Naxi homegardens and associated ethnomedical knowledge between Naxi healers and farmers.

METHODS

Ethnobotanical homegarden surveys were conducted with three Naxi healers and 28 farmer households in two Naxi communities in Lijiang Prefecture in Northwest Yunnan Province of China. Surveys included inventories of medicinal plants in homegardens and semi-structured interviews with homegarden managers to document traditional medicinal uses of inventoried plants. Inventoried plants were classified into 13 'usage categories' of medical condition groupings that impact a system of the body. Finally, plant species richness was calculated for each homegarden and species richness was compared between healers and farmers as well as between study sites using a Least Square Means Tukey HSD function.

RESULTS

Ethnobotanical surveys at the study sites found that 13% of households rely exclusively on traditional Naxi medicine, 26% exclusively use Western medicine and 61% use a combination of traditional Naxi and Western medicine. A total of 106 medicinal plants were inventoried in Naxi homegardens representing 50 botanical families. Over 85% of inventoried medicinal plants were herbaceous. The most represented families were Asteraceae (12.8%), Ranunculaceae (8.3%), Apiaceae (8.3%), and Polygonaceae (7.3%). The primary medical functions of inventoried plants were to treat inflammation (73 species), circulatory system disorders (62), nervous system disorders (41), detoxification (39), digestive system disorders (33), muscular-skeletal system disorders (26), genitourinary system disorders (26), skin conditions (23), respiratory systems disorders (22), and cold and flu (20). Local herbal experts maintained greater medicinal plant species richness in their homegardens compared to local farmers as well as had greater knowledge of medicinal functions of plants. Healers maintained medicinal plants primarily for healing while farmer households maintained approximately 90% of the medicinal plants in their homegardens for commercialization and the remaining for household healthcare.

CONCLUSIONS

This study highlights the importance of biodiversity and traditional ecological and medical knowledge for human wellbeing and livelihoods in Naxi communities. Conservation efforts and policies are necessary to preserve the ecological and cultural base that maintains medicinal plant use by both healers and farmers in Naxi homegardens of the Sino Himalayan region.

Microsatellite marker development in tung trees (Vernicia montanaand V. fordii, Euphorbiaceae)

PREMISE OF THE STUDY

The tung tree is valuable for tung oil, which is derived from the oilseeds of the tree. Microsatellite markers were developed in tung trees (Vernicia montanaand V. fordii) for use in population genetic studies and, particularly, analyses of genetic relationships among germplasms.

METHODS AND RESULTS

A total of 20 microsatellite markers were developed and characterized in V. montanaand tested for cross-amplification in V. fordii, using the Fast Isolation by AFLP of Sequences COntaining Repeats protocol. These markers showed rich polymorphism when assessed in 120 samples of V. montanaand six samples of V. fordii.

CONCLUSIONS

The developed microsatellite markers will be of great use for investigating genetic diversity of germplasms, analyzing population structure, and facilitating molecular breeding in tung trees.

The effects of cooking oil fume condensates (COFCs) on the vegetative growth of Salvinia natans (L.) All

Cooking oil fumes (COF) and their condensates (COFCs), which are suspected of causing human lung cancers, are hazardous materials to environments. The effects of COFCs on the vegetative growth of Salvinia natans (L.) All., a free-floating aquatic fern, are discussed in this paper. The results showed that there were no differences of the number of floating leaves and the mean numbers of new leaves of S. natans in all groups, but these indices in experimental groups were influenced obviously at the late stage. COFCs also influenced stem length and number of buds of S. natans. COFCs could cause the floating leaves to turn yellow and individuals to die quickly. All these effects were correlated with the concentration of COFCs and the time. When the concentration of COFCs was > or =0.18 g/l, above 80% individuals would die in a short time. COFCs had significant impacts on the decrease in photosynthetic areas of S. natans by making the floating leaves turn yellow faster and accelerating the decomposition. There were some components in minute amount benefiting to the growth of S. natans. S. natans was sensitive to COFCs and could be a potential indicator for monitoring COFCs pollution in aquatic environments.

Transposable DNA elements and life history traits: II. Transposition of P DNA elements in somatic cells reduces fitness, mating activity, and locomotion of Drosophila melanogaster

Some transposable DNA elements in higher organisms are active in somatic cells, as well as in germinal cells. What effect does the movement of DNA elements in somatic cells have on life history traits? It has previously been reported that somatically active P and mariner elements in Drosophila induce genetic damage and significantly reduce lifespan. In this study, we report that the movement of P elements in somatic cells also significantly reduces fitness, mating activity, and locomotion of Drosophila melanogaster. If other elements cause similar changes in life history traits, it is doubtful if transposable DNA elements remain active for long in somatic cells in natural populations.

Clusters of new identical mutants and the fate of underdominant mutations

Given favorable environmental and demographic conditions, premeiotic clusters of identical mutations can produce a broad distribution of the initial frequency of underdominant alleles. Because of these clusters, new underdominant mutations may not necessarily be as rare in a population as previously assumed. The fixation of underdominant mutations, especially those with low heterozygous fitness, is increased when mutations appear in a cluster due to a genetic change that occurred before germline differentiation. Most restrictions on the fixation of underdominant mutations in a single population, such as strong genetic drift, weak selection against mutant heterozygotes, isolated population structure, inbreeding, meiotic drive, and selection in favor of mutant homozygotes can be relaxed or even dropped. Instead, the fate of strong underdominant mutations is determined mainly by ecological and genetic factors that affect the cluster size distribution of new premeiotic mutations. Accumulation of reproductive isolation by the fixation of underdominant mutations becomes more feasible with clusters, and mutation is not always the weakest force during this evolutionary process. The large mean and variance of reproductive success in many multicellular species make it possible that even underdominant mutations with very low heterozygous fitness could contribute substantially to reproductive isolation.

Mutation rate: a simple concept has become complex

The factors that cause new mutations or affect the rate at which they occur have important implications for many areas of genetics. But recent work on phenomena such as premeiotic mutations, which yield a cluster of identical new mutants at the some time, led us to realize that researchers are using the term "mutation rate" in different, and sometimes contradictory, ways. One premeiotic genetic change may ultimately yield several new mutant offspring, but should this be considered one new mutation or many? The way the data are handled in analyses can have a significant effect on the results. How, then, does one handle clusters in the estimation of mutation rates? We explore this question and propose that geneticists begin to distinguish clearly between three different phenomena that to this point have been given the same name: the initial prerepair "genetic damage rate," the postrepair "mutational event rate," and the observed "mutation rate" as it is expressed in the proportion of new mutant offspring. We believe that all new mutant offspring should be counted when estimating mutation rate, irrespective of when in the developmental cycle it is believed that the initial mutational event occurred.

Clusters of identical new mutations can account for the "overdispersed" molecular clock

Germ-cell mutations may occur during meiosis, giving rise to independent mutant gametes in a Poisson process, or before meiosis, giving rise to multiple copies of identical mutant gametes at a much higher probability than the Poisson expectation. We report that the occurrence of these early premeiotic clusters of new identical mutant alleles increases the variance-to-mean ratio of mutation rate (R(u) > 1). This leads to an expected variance-to-mean ratio (R(t)) of the molecular clock that is always greater than one and may cover the observed range of R(t) values. Hence, the molecular clock may not be over-dispersed based on this new mutational model that includes clusters. To get a better estimation of R(u) and R(t), one needs measurements of the intrageneration variation of reproductive success (Nt/Ne(i)), population dynamics (ki), and the proportion of new mutations that occur in clusters (rc), especially those formed before germ-cell differentiation.

Clusters of identical new mutation in the evolutionary landscape

In contrast to the common assumption that each new mutant results from a unique, independent mutation event, clusters of identical premeiotic mutant alleles are common. Clusters can produce large numbers of related individuals carrying identical copies of the same new genetic change. By entering the gene pool in multiple copies at one time, clusters can influence fundamental processes of population genetics. Here we report evidence that clusters can increase the arrival and fixation probabilities and can lengthen the average time to extinction of new mutations. We also suggest it may be necessary to reconsider other fundamental elements of population genetic theory.