Kliment Arkadievich Timiryazev is born on June 3rd, 1843, in Saint Petersburg in a large noble family. His father, Arkadiy Semenovich, heads customs department in Saint Petersburg, thus using every opportunity to give his son profound home education. His mother, English by birth, helps young Kliment to learn several foreign languages, English, German and French among them, and to get acquainted with famous Russian and foreign books. Kliment also receives music and esthetic lessons, which later bring style to his literary and scientific works.

Kliment Arkadievich enters faculty of natural sciences of Saint Petersburg’s university, but is dismissed from the university in 1861 for taking part in student riots. Timiryazev continues his education as an irregular student and graduates from the university in 1866 with a gold medal for his work on liverworts’ structure.

Timiryazev considers plant physiology and agricultural chemistry to be the basis of rational agricultural activities, and since 1867 Kliment Arkadievich heads an experimental ground, where he performs some experiments with mineral fertilizers, studying their effect on plants.

In 1868 Timiryazev makes a report at the First Congress of Natural Scientists in Saint Petersburg, where describes a unit for studying mechanisms of plant leaves’ air feeding – his first scientific work. In the same year Kliment Arkadievich is assigned abroad to do some practice in laboratories of famous chemists and physiologists.

In 1870 Timiryazev starts his teaching activities in Petrovskaya Agricultural Academy, which will last for over 20 years – the time he later claims to be the happiest years of his life, combining his youth, enormous but fruitful scientific work and personal happiness. In 1871 he defends his Master thesis on chlorophyll’s spectral analysis; and in 1975 his Doctor thesis on light consumption by plants is finished and defended. In 1878 he becomes the professor of Moscow University and publishes his world famous book “The life of plant”, which is republished over 20 times both in Russia and abroad.

In 1884 Timiryazev becomes the chairman of Botanic Society of natural scientists, anthropologists and ethnographers. Timiryazev’s studies of photosynthesis in plants result in the fact that plants assimilate carbon from air’s carbon dioxide using energy of light, mainly red and blue light ranges, where chlorophyll has maximum absorbance. Timiryazev is the first to suggest that chlorophyll takes part in photosynthesis not only physically, but also chemically, thus anticipating modern theory. The biologist shows that photosynthetic activity changes proportionally depending on energy consumed under relatively low light intensity, however, when light intensities grow, photosynthetic activity reaches some permanent values and doesn’t show any further changes – he calls this effect “light saturation of photosynthesis”. Thus, the scientist demonstrates how energy conservation law and first law of photochemistry can be applied to photosynthesis.

In 1896 Timiryazev demonstrates first Russian greenhouse and plant growing experimental station at the All-Russian exhibition in Nizhniy Novgorod. His lecture course of 1897 “Plant physiology as the basis for rational agriculture” is dedicated to mineral fertilizers and their efficiency. Later, his “Plants fighting drought” lecture summarizes data on water intake schedule and plant drought-resistance, giving practical recommendations for lowering drought damage.

In 1903 Kliment Arkadievich reads a public lecture in London called “Plant’s role in space”, where he summarizes his long-term studies of photosynthesis. He shows photosynthesis of green plants as a primary source of organic matter and stored energy, essential for vital functions of all organisms. Timiryazev’s discovery of energy patterns of photosynthesis is a great contribution to the theory of unity and relations of living and non-living matter in energy and matter cycles in nature.

In 1906 Timiryazev publishes his collected articles on agriculture and plant physiology. Kliment Arkadievich is among the first propagandists of Darwinism in Russia – he considers Darwin’s theory of natural selection as most outstanding scientific achievement of the 19th century. The biologist publishes several works, on Darwin’s theory, where he develops the theory, uses it as explanation for many natural phenomena and defends it from churchmen and other Darwin opponents. Timiryazev makes a fantastic contribution to popularization of science – since he starts thinking, he sets two tasks for himself: working for science and writing for people, and he definitely succeeds in both.

In 1909 Timiryazev becomes a Doctor of Honour of Cambridge and Geneva universities, and in 1913 Kliment Arkadievich celebrates his 70th anniversary in Geneva university, a real festival of world science.

Kliment Arkadievich Timiryazev dies on April 26, 1920, being seriously ill. Moscow boasts a monument to this outstanding Russian scientist and citizen.

Sources:
    Library of the Academy named after Timiryazev
    Encyclopedia

Kizilova Anna