Who discovered plant hormone auxin?

Getting Started

The discovery of plant hormones has contributed greatly to our understanding of plant growth and development. One of the most important plant hormones is auxin, which plays a crucial role in various physiological processes, including cell elongation, root development, and tropism. The identification of auxin as a key regulator in plants was a landmark achievement in the field of plant biology. In this article, we will explore the history of the discovery of auxin and the scientists who made significant contributions to its understanding.

Charles Darwin and the pioneering studies

The first observations of the effects of auxin-like substances can be traced back to the work of the renowned biologist Charles Darwin. In the late 19th century, Darwin and his son, Francis Darwin, conducted experiments on phototropism, the phenomenon of plants bending toward a light source. They noticed that the bending continued even when the tip of the plant was removed. This led them to propose the existence of a signaling substance that moved from the tip to the rest of the plant. However, the exact nature of this substance remained a mystery.

Fritz Went and the first isolation of auxin

It was not until the 1920s that significant progress was made in identifying and isolating auxin. In 1926, a Dutch biologist named Frits Went made a groundbreaking discovery. Went was studying the phenomenon of phototropism in oat coleoptiles, the protective sheath that covers a plant’s emerging shoot. He hypothesized that the bending of the coleoptile was due to a chemical substance produced at the tip. Went extracted this substance and named it “auxin,” derived from the Greek word “auxein,” meaning to grow.

Went’s experiments showed that auxin could induce bending in other parts of the plant and promote cell elongation. He also showed that the movement of auxin was polar, with a unidirectional flow from the tip to the base of the plant. These findings revolutionized our understanding of how plants respond to light and gravity.

Kenneth Thimann and the identification of indole-3-acetic acid (IAA)

Building on Went’s work, American botanist Kenneth Thimann made a major contribution to the field in the 1930s. Thimann successfully isolated and identified the compound responsible for the growth-promoting effects of auxin as indole-3-acetic acid (IAA). Thimann’s experiments showed that IAA was synthesized in the tips of plants and transported downward, where it influenced various physiological processes.

Thimann’s work laid the foundation for further investigations into the biosynthesis, metabolism, and mechanisms of action of auxin. His research provided valuable insights into the role of auxin in plant growth and development and opened new avenues for the study of plant hormones.

The Modern Era: Advances in Auxin Research

Since the pioneering studies of Darwin, Went and Thimann, the field of auxin research has made remarkable progress. With the advent of molecular biology techniques, scientists have identified key genes involved in auxin biosynthesis, transport, and signaling pathways. They have also discovered other forms of auxin, such as indole-3-butyric acid (IBA) and phenylacetic acid (PAA), adding to our understanding of the complexity of auxin signaling.
In addition, the development of advanced imaging techniques and genetic tools has allowed researchers to visualize auxin distribution and activity at the cellular and subcellular levels. These studies have revealed the spatio-temporal dynamics of auxin gradients during various developmental processes and shed light on the precise mechanisms underlying auxin-mediated growth responses.


The discovery of auxin and the subsequent elucidation of its functions have had a profound impact on the field of plant biology. From the initial observations of Charles Darwin to the pioneering work of Fritz Went and Kenneth Thimann, scientists have made significant progress in unraveling the mysteries of auxin. Today, auxin continues to be the subject of intense research as scientists strive to uncover the intricate mechanisms by which this hormone regulates plant growth and development. The knowledge gained from these studies not only enhances our fundamental understanding of plants, but also holds promise for applications in agriculture and horticulture, where manipulation of auxin signaling can lead to improved crop productivity and stress tolerance.


Who discovered plant hormone auxin?

The plant hormone auxin was discovered by Charles Darwin and his son Francis Darwin.

When was the discovery of plant hormone auxin made?

The discovery of the plant hormone auxin was made in the late 19th century, specifically in the year 1880.

How was the plant hormone auxin discovered?

The Darwins discovered auxin through their experiments on phototropism, the bending of plant stems towards a light source. They observed that the bending occurred even when the tip of the stem was covered, leading them to hypothesize the existence of a signal coming from the tip. They named this signal “auxin.”

What is the role of plant hormone auxin?

Auxin plays a crucial role in various aspects of plant growth and development. It regulates cell elongation, promotes apical dominance, stimulates root formation, and is involved in tropic responses such as phototropism and gravitropism.

What are some natural sources of plant hormone auxin?

Natural sources of auxin include the tips of growing shoots, young leaves, developing seeds, fruits, and root tips. It is produced in these plant parts and then transported to other parts of the plant to exert its effects.