astronomy

Léon Guignard

Léon Guignard is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Léon Guignard rather than just read about it. In short: Jean Louis Léon Guignard (13 April 1852 in Mont-sous-Vaudrey – 7 March 1928 in Paris) was a French pharmacist and botanist. In 1882 he received his doctorate of sciences in Paris, and afterwards served as a professor of botany at the Faculty of Sciences of Lyon.

Key takeaways

Léon Guignard belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Léon Guignard to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Léon Guignard from memory before moving on to harder problems.

Reference excerpt

Jean Louis Léon Guignard (13 April 1852 in Mont-sous-Vaudrey – 7 March 1928 in Paris) was a French pharmacist and botanist. In 1882 he received his doctorate of sciences in Paris, and afterwards served as a professor of botany at the Faculty of Sciences of Lyon. In 1887, he succeeded Gaspard Adolphe Chatin as chair of botany at the Ecole Supérieure de Pharmacie in Paris. From 1900 to 1910 he was dean to the faculty of pharmacy. In 1899 he was named president of the Académie des sciences. He was also a member of the Société de biologie (from 1888), the Académie de Médecine (from 1897) and the Académie d'Agriculture (from 1915). In 1920 he was chosen a commander in the Legion d'Honneur.

Along with biologist from Kyiv Sergei Navashin, he is credited as the co-discoverer of double fertilization in flowering plants. The two men made their discoveries independent of each other, Navashin in 1898 and Guignard in 1899. He also introduced a new method for detecting the presence of hydrocyanic acid in plants. In addition, he conducted significant research on the origin and structure of integuments for a large number of seeds. In 1892, botanists Pierre Viala and Louis Etienne Ravaz published Guignardia,which is a genus of fungi in the family Botryosphaeriaceae and named in Guignard's honour.

Selected works Recherches anatomiques et physiologiques sur l'embryogénie des légumineuses, 1881 – Anatomical and physiological research on the embryology of legumes. Recherches sur le sac embryonnaire des phanérogames angiospermes, 1882 – Research on the embryonic sac of angiosperms. Sur la division du noyau cellulaire chez les végétaux, 1883 – On the cell nucleus division in plants. Nouvelles observations sur la structure et la division du noyau cellulaire, 1884 – New observations on the structure and the division of the cell nucleus. Sur les organes reproducteurs des hybrides végétaux, 1886 – On the reproductive organs of plant hybrids. Sur les effets de la pollinisation chez les orchidées, 1886 – The effects of pollination in orchids. Observations sur l'appareil mucifère des Laminariacées, 1892 – On the muciferous apparatus in Laminariaceae. Recherches sur le développement de la graine et en particulier du tégument séminal, 1893 – Research on the development of seeds, in particular the seed coat. L'origine des sphères directrices, 1894 – The origin of director spheres. Les découvertes récentes sur la fécondation chez les végétaux angiospermes, 1899 – Recent discoveries on fertilization in angiosperms. Sur les anthérozoides et la double copulation sexuelle chez les végétaux angiospermes, 1899 – On antherozoids and double copulation in angiosperms. La double fécondation chez les renonculacées, 1901 – Double fertilization in buttercups. Sur la double fécondation chez les solanées et les gentiancées, 1901 – Double fertilization in Solanaceae and Gentianaceae. Le haricot a acide cyanhydrique (Phaseolus lunatus), 1906 – A bean containing hydrocyanic acid (Phaseolus lunatus). L'ovule chez les Apocynacées et Asclépiadacées, 1910 – The ovule in Apocynaceae and Asclepiadoideae.

References

Illustrations

Worked examples

Example 1 — a first encounter with Léon Guignard

Start with the simplest possible case. Write down what Léon Guignard claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Léon Guignard before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Léon Guignard ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Léon Guignard

In research: Léon Guignard appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Léon Guignard in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Léon Guignard is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1852 births, 1928 deaths, 19th-century French botanists, so understanding it makes those chapters shorter.
In everyday life: Look for Léon Guignard outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Léon Guignard” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Léon Guignard in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Léon Guignard means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Léon Guignard out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Léon Guignard in simple terms?

Why does Léon Guignard matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Léon Guignard?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Léon Guignard.