In summer 2020, researchers from the Institute for Environmental Solutions (IES) launched the study on commercial propagation of endangered medicinal and aromatic plants by using tissue culture method. This approach will provide an opportunity to cultivate endangered species in organic farming.
Along with the increased pharmaceutical, cosmetology, and food industry demand for medicinal and aromatic plants (MAPs), populations of many wild species are decreasing. Therefore, researchers are eager to study the cultivation of endangered plant species in organic farming. This solution will reduce pressure on wild populations, as well as ensure sufficient amount of high-quality plant-based materials for different industries.
Three endangered wild medicinal plant species with high market potential were selected for this research – Siberian ginseng (Eleutherococcus senticosus Maxim.), common yew (Taxus baccata L.) and sea holly (Eryngium maritimum L.). During 3-year period IES researchers will develop efficient and economically viable propagation methods of these plants for commercial use in organic farming.
In the following interview, IES leading researcher Dr Ieva Mežaka highlighted the progress and the importance of this research.
IES: Why is it necessary to do this research?
Dr Ieva Mežaka (I.M.): 90% of medicinal and aromatic plants are harvested in wild and only 10% are cultivated. Increasing harvesting of MAPs in the wild, along with the loss of natural habitats, bring a heavy burden on wild populations, therefore, many of them are endangered. Meanwhile, human population is growing and so is the market demand for MAPs. In this research, we are looking for ways to grow medical and aromatic plants more effectively – by cultivating them in organic farming. Another important challenge is to seek for the growing technologies that could provide the highest harvests and concentration of active compounds in plants.
IES: Why did you choose these 3 MAPs – Siberian ginseng (Eleutherococcus senticosus Maxim.), common yew (Taxus baccata L.) and sea holly (Eryngium maritimum L.)?
I.M.: Main reason was the high market demand for these MAPs due to which their wild populations are endangered. During this research, we will develop technologies for cultivation of these endangered MAPs in organic farming, thus decreasing the pressure on wild populations. Additional factors for selecting these plants were their unifying vulnerabilities – prolonged seed germination, low seed production and slow rooting of cuttings.
IES: You mentioned that the selected MAPs have a high market demand. Where exactly one can use active compounds of these plants?
I.M.: 60% of all produced pharmaceuticals contains active compounds extracted from medicinal and aromatic plants. Wild Siberian ginseng, common yew and sea holly has high concentration of different active compounds widely used in pharmaceutical, food and cosmetics industries. For example, common yew is used for development of anti-cancer drugs. Moreover, research shows that Siberian ginseng has a stimulating and antidepressive effect, but Sea holly is used for liver and kidney disease cures.
IES: Please explain this plant tissue culture propagation method?
I.M.: It is a biotechnology method that allows us to propagate plants by using tissue cultures. We grow these plants in laboratory test tubes, but we do not change their genetics. This method can be divided in four steps:
First step. We start with seed germination then we grow a plantlet.
Second step. Then we do micro-propagation. We take that plantlet that we grew and cut it in pieces. From these pieces we can re-grow new plantlets and continue this process in geometrical progression.
Third step. Rooting of the plantlets propagated in the second step.
All this process is done in controlled and sterile conditions. Micro-propagation and rooting require adaptation of each medium composition that we are providing to the plantlets. This includes the composition of micro-and macro-elements, vitamins, growth regulators, various other additives, and their concentrations. This is important process because it determines the growing conditions of plant and plantlet development.
Fourth step. Adaptation of plants grown in laboratory conditions to conventional growing conditions in soil. Plants that are propagated in these circumstances where we provide suitable environment – nutrients, humidity, suitable temperature etc., are relatively fragile to external impact factors.
IES: Why did you choose this method instead of other easier approaches?
I.M.: All three of the researched plants under normal propagation conditions germinate slowly and unevenly. It takes up to 18 months to sprout Siberian ginseng seeds and they need stratification – a simulated set of environmental effects in controlled conditions which accelerate seed sprouting. For example, by subjecting seeds to cold treatment we simulate the period that seed experiences under natural conditions during winter. Plant tissue culture method in propagation process allows us to exclude the long seed sprouting procedure. We sprout the gathered seeds once at the beginning of the research and afterwards we work only with plantlets and micro-propagation. This process is much faster than other more traditional propagation methods, therefore more suitable for commercial cultivation. Additionally, this method allows us to do chemical analysis of plantlets, thus allowing us to understand which plants have higher concentration of active compounds. Then we can choose which ones to propagate for commercial use.
IES: Is it planned to propagate populations harvested in Latvia?
I.M.: In Latvia wild populations of common yew and sea holly can be found but wild Siberian ginseng is common in Russia and China. For last few decades private farmers have proven that it is possible to cultivate Siberian ginseng in natural conditions of Latvia. Within this research we were interested to gather wild population samples as well as ones that are grown by farmers from Latvia and other natural distribution areas of these plants.
We launched this research in summer of 2020. So far, we have already implemented sampling campaigns where we collected different parts of plants (leaves, branches, roots) and seeds. In Latvia, these plants are endangered, therefore we needed to get a special permission approved by the Nature Conservation Agency. We have gathered samples of all three species found in Latvia (wild species and samples from private growers). We also carried sampling expeditions to Saaremaa and Kihnu islands in Estonia. Also, for these expeditions we needed to get a special permission from Environmental Board.
We were planning to carry sampling campaigns in other natural distribution areas of these plants, but out plans were disrupted by COVID-19 pandemic. We adapted to this situation and found other solutions for collection of samples. In seed exchange programs we were able to gather several samples from the collections of national botanical gardens, universities and private growers from Latvia and other countries.
IES: What have you planned for the next research periods?
I.M.: Sample gathering campaigns are concluded. We have started the work with seed stratification and introduction of seeds to plant tissue culture. Researchers in the laboratory began the assessment to find the best approach of chemical analysis for all three researched MAPs. We are developing a methodology and preparing extracts for chemical analysis. That will help us understand what kind of active substances are in the researched plants and how they differ between populations. Thus, we hope to find out which of the researched populations are the most valuable ones.
Research on plant tissue culture application for commercial propagation of endangered medicinal plants is developed as a part of the European Regional Development Fund programme 1.1.1 "Improve research and innovation capacity and the ability of Latvian research institutions to attract external funding, by investing in human capital and infrastructure" 220.127.116.11. measure “Support for applied research”, Nr. 18.104.22.168/19/A/083.
More about the project here.