Strategic Importance of Scientific Education for the Botanic Garden of the City of Paris
Contributed by Laurent Bray*, Geneviève Beraud*, Monique Belin**, Karine Boudjoulian**, Jean-Sébastien Robert**, Patrick Thommen***, Julie Didierjean***
*Jardin Botanique de la Ville de Paris, Mairie de Paris, DPJEV, 1 avenue Gordon Bennett, 75 016 Paris
**Laboratoire de Botanique Tropicale, Université P.& M. Curie, 12 rue Cuvier, 75 005 Paris
***Lycée Janson de Sailly, 75 016 Paris
In 1995, the Green Spaces Department of the City of Paris decided to create a botanical garden using four sites which were traditional public gardens: the Garden and the Greenhouses of Auteuil, the Park of Bagatelle, and the Floral Park and the School of Horticulture of Du Breuil. The global strategy that has been followed was explained at the Botanic Gardens Conservation International Conservation Congress in South Africa in 1998. To summarise, the first step was to analyse the pre-existing assets and to compare them to some other famous botanic gardens; benchmarking. After this, objectives were determined as well as means to fulfil them identified. Throughout this process the charter of the French Speaking Botanical Gardens Association was used as a guideline. The purpose of this presentation is to illustrate the importance of scientific education in the Botanical Garden of the City of Paris and highlight what has been achieved in this field.
The characteristics of this botanical garden will first be explained and its strategy will be presented in relation to the charter of the French Speaking Botanical Gardens Association. Following, the positive and negative aspects of scientific education, as they existed in 1994, will be presented. Human resources were a prerequisite for good educational activities and achievements since 1994 will be highlighted. Lastly, the education strategy will be outlined and illustrated using examples and the conclusions will address future propositions.
The Botanical Garden of Paris
The botanical garden is made up of four sites:
- to the west of Paris is the 6.5 hectare Garden and Greenhouses of Auteuil which was built in 1898 and has 4060 accessions;
- the Park of Bagatelle with 2730 accessions was built in 1777 on 24 hectares;
- to the east of Paris, the Floral Park with 5960 accessions was built in 1969 on 31 hectares; and
- the School of Horticulture of Du Breuil and its arboretum, with 2220 accessions and numerous educational plant collections, was built in 1936 at its new location on 22 hectares.
The botanical garden is a horizontal structure inside the Green Spaces Department of the City of Paris. A specific software has been developed for the botanical garden which works on a local network (an intranet) and which complements the second version of International Transfer Format (ITF). Since 1995, a seed bank, herbarium and a fruit and seeds collection have also been created. The botanical garden was recognised by the French Speaking Botanical Gardens Association in 1998.
The French Speaking Botanical Gardens Association
The French speaking botanical gardens association states that a botanical garden must undertake education, scientific activities and conservation projects. To summarise, the overall goal is to combine these three areas and take into account the botanical garden’s historical tradition in horticulture and its limited budget.
Analysis of the Previous Situation
Positive Aspects in Education
The first step for the Botanical Garden of the City of Paris was to analyse the pre-existing situation. From an educational perspective there were two main assets: firstly the school of horticulture, whose quality of courses is well recognised, and which also has a library with more than 11 500 references; and secondly the education service of Paris-Nature catering for children between 5-12 years old. Paris-Nature was created in 1983 and aims to:
- communicate to Parisians of all ages and to teach them about fauna, flora, water, air, soil and their environment;
- teach the community to observe, love and protect their environment; these successive stages in the educational process are necessary to respect nature and bring about a responsible attitude.
To fulfil these objectives, numerous activities have been proposed to bring a dynamism, which leads to a growing public awareness of the environment. Twelve places, each having a specific Parisian theme on nature, are connected to the parent house, placed in the Parc Floral. The equipment is situated in different parts of the city such as the Maison de l'Air which is perched at the top of a hill (Parc de Belleville – 20th district) and the Ferme George-Ville displaying breeding and crops on five hectares (Bois de Vincennes – 12th district).
In addition, posters and brochures are developed and distributed and booklets outline details of walks in all the districts of the city. Protection actions for fauna and flora have been installed in the city such as ornithological reserves, nests for tits and owls, and plant conservatories as wild and natural gardens. Finally, exhibitions on different environmental themes contribute to sensitising the public. Ninety pedagogues conduct educational activities, led by Paris-Nature. Their priority is to target youth from kindergarten to middle school.
In all the nature houses, there are workshops with different activities adapted to each age category. For example, the House of Five Senses (13th district) caters for 5-8 year old children who discover nature by using their five senses. For the 8-12 year olds, a video-bus and a laboratory-bus aid them in exploring gardens and woods. The activities are complementary, for example in the wild garden (18th district) the children can discover natural characteristics of the city, in the gardening house (12th district) they learn how to cultivate plants, whereas in the gardening workshops (16th district) they create miniature gardens. This year, in 1999, 40 000 school children between 5-12 years old have visited the different houses and it is predicted that these houses will answer an ever growing demand.
Weak Aspects in Education
Though there are some positive key-assets, some weak aspects in education were also identified:
- human resources were not adequate for scientific education;
- there was no project for conservation and/or scientific education;
- there was no existing link with universities; and
- budgets were limited (but it is a limitation common to all of us).
All the solutions we developed in response to these points since 1994 are going to be presented.
Responses to the Weakness in Science Education
Concerning human resources, our objective was to increase our credibility and efficiency in scientific activities, to improve our links with universities, and to produce scientific publications.
The solution was to employ a PhD student in Plant Biology (in 1994) with field experience in plant conservation, an engineer in agronomy (in 1996), and a Professor of Horticulture with 20 years experience in education (in 1998).
The main results were:
- a collaboration with universities which increases each year;
- publications in plant systematic;
- the creation of courses in botany and horticulture; and
- the development of research activities in seed physiology and in plant physiology as an adaptation to biotopes.
The botany courses created only two years ago are now overbooked. They consist of a basic level of six courses and an advanced level of six courses. There are two sessions during summer and autumn and the general public of all ages attend these courses. The main objectives of the basic level courses are to give definitions of the mains parts of plants and to enable people to develop skills in the identification of wild plants of France by using floral keys.
Strategy in Science Education
A strategy was also created in science education and conservation. The objectives were to:
- have low cost research and to undertake applied research and leave fundamental research to the university;
- have a scientific strategy correlated with other activities of the botanical garden and with conservation (to reduce the costs of research activities).
Elaboration of a Strategy and Materials
Therefore, the scientific strategy involved the following:
- priority was given to seed physiology inside the botanical garden because it had a strong correlation with seed bank activities;
- developing joint projects with universities for other research activities.
To fulfil this strategy, numerous other botanical gardens were visited before the creation of the seed bank, to determine on which plant species we had to focus and on which methodology was to be used for collecting, seed testing and seed conservation. Minimum equipment was bought, including three incubators and an infrared dessiccator. These three incubators allowed us to conduct sound germination tests, but were also used, because of lack of room, for storing seeds. While taking into account previously published results, the infrared dessiccator allowed us to determine, with a very small quantity of plant material, the category of the seeds (i.e. orthodox seeds that are kept at 5°C with silica gel; and recalcitrant seeds that are kept at 15°C without silica gel).
Examples of Some Results
Scientific Education Inside the Garden
Seed Tests on Cladrastis lutea
The first species on which studies were conducted was from the family Fabaceae because seeds belonging to this family only have tegument inhibition and are therefore easier to work with and could be used as a start point. On Cladratis lutea, the effects of temperature (5°C, 15°C, 25°C and 32°C) and sulphuric acid (5 min and 10 min-bath) were studied. At 32 °C, lethality was so high that no seed survived after 15 days. The optimal germination was obtained at 25°C after a 10 min bath in sulphuric acid.
Seed Tests on Crambre maritima and Dianthus superbus
After this first species which was quite easy to work on, other studies included the breaking of dormancy by cold treatment or hormonal applications. Research is currently being conducted in the botanical garden to determine the conditions for optimal germination of Crambe maritima and Dianthus superbus. These two species are protected under French national laws and very interesting results were obtained concerning conservation and regeneration of their seeds, even after long term storage of 10 years.
Scientific Education in Collaboration with Universities
Other studies interested the universities but had few links with the seed bank, therefore joint projects were created with these institutions. The botanical garden donated plant material, and offered expertise in botany and plant physiology. Studies, which did not concern seed physiology during the last three years, were as follows:
- water translocation in Dionaea muscipula in relation to leaf movements;
- hydatherous cells of Crassula argentea for water absorption; and
- nectar secretion in Pseudobombax ellipticum.
Leaf Movements in Dionaea muscipula
A team of undergraduate students supervised by Patrick Thommen studied the mechanisms of the closing of leaves of Dionaea muscipula. The different phases can be summarised by the following sequence: induction of closing after contact with the sensitive specialised epidermis cells, a fast closing after induction and a long re-opening phase.
It is well known that leaf movement is linked to a potential of action. The depolarisation phase is very fast and corresponds to the leaf closing ; the repolarisation is much longer and corresponds to the re-opening of the leaf.
Osmotic pressure also plays a role in the closing of the leaf. The number of leaves closed or opened has been correlated with the concentration of saccharose. The lower the osmotic pressure, the higher the number of closed leaves there are. The entrance of water in the leaf (lowest concentrations of saccharose) is therefore correlated with the leaf closing.
In a closed leaf, it was shown that the abaxial epidermis cells were smaller than the adaxial ones that had a greater vacuole. The hypothesis was made that closing mechanisms are due to the turgescence of cells and differential water translocation, between adaxial and abaxial epidermis cells.
Hydathodes of Crassula argentea
Crassula argentea is a South African plant and its natural habitat is in the desert of Karoo. The crassulescent leaves are very rich in hydatherous cells that constitute a specialised structure represented by red spots above the succulent leaf.
Cytological studies show that this structure is in a shallow crypt and that three histological zones can be described. First a stomatiferous epidermis, then hydathiferous cells for water absorption, which are contiguous, finally tracheids beneath to conduct the water to the vessels. Cells rich in mucilage surround the hydathode.
This structure is very similar to the hydathode of Ficus diversifolia, but the first one is used for water excretion and the second for water absorption. Both of them are specialised structures of adaptation to the natural habitats.
Extra Foliar Nectar Secretion in Pseudobombax ellipticum
Pseudobombax ellipticum that grows in our arid climate greenhouse was used for the study of nectar secretion in this species. Extra floral nectaries are located in two places; the first is on the leaf mid-vein and has a circular form; the second is situated on the petiole, produces a great amount of nectar and looks like a knife cut.
Histological studies show that the petiolar nectary is composed of trichomes, secreting cells beneath, and a base of mucilaginous cells and cells with oxalate of calcium crystals. There are two layers of trichome cells upon a stalk composed of two cells. Secreting cells are characterised by their opacity to electrons and by numerous organelles such as mitochondria’s and amyloplasts. Secreting cells are also characterised by a well developed endoplasmic reticulum.
Other Factors Concerning Scientific Education
Another weak point in scientific education was the limited contacts we had with universities. We increased them by having partnership projects as previously discussed but also by having trainees in the botanical garden. During the last three years, students have spent 48 months training. We are also participating in the updating of the systematic courses of the University of Orsay and a joint publication has been produced.
Some other publications were also written on the new ordinal classification of flowering plants according to the angiosperm phylogeny group. In these publications, the results of this group were applied to the West European flora.
To increase the links with universities, we also participate in student excursions during their course to help them discover the wild flora around Paris and we donate plant material for DNA sequencing.
During the last four years, a benchmarking process has been used to transform a traditional city garden into a botanical garden with the help of the guidelines defined in the charter of French-speaking Botanical Gardens Association. This process has been particularly successful in science education and many realisations have been achieved: courses in botany, research and science activities, increased links with universities, joint projects with universities, and scientific publications. In the future, our objective is to focus on scientific publications and on conservation projects especially in developing countries.