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Figure. Chemical Structures of the Plant Hormones, from PLoS

Hormonal Regulation of Plant Growth and Development
Primer by William M. Gray

Primers provide a concise introduction into an important aspect of biology highlighted by a current PLoS Biology research article.

Plant growth and development involves the integration of many environmental and endogenous signals that, together with the intrinsic genetic program, determine plant form. Fundamental to this process are several growth regulators collectively called the plant hormones or phytohormones. This group includes auxin, cytokinin, the gibberellins (GAs), abscisic acid (ABA), ethylene, the brassinosteroids (BRs), and jasmonic acid (JA), each of which acts at low concentrations to regulate many aspects of plant growth and development.

With the notable exception of the steroidal hormones of the BR group, plant hormones bear little resemblance to their animal counterparts (Figure 1). Rather, they are relatively simple, small molecules such as ethylene gas and indole-3-acetic acid (IAA), the primary auxin in the majority of plant species. The concept of plant hormones originates from a classical experiment on phototropism, the bending of plants toward light, carried out by Charles Darwin and his son Francis in 1880. The Darwins were able to demonstrate that when oat seedlings were exposed to a lateral light source, a transported signal originating from the plant apex promoted differential cell elongation in the lower parts of the seedling that resulted in it bending toward the light source. This signal was subsequently shown to be IAA, the first known plant hormone...continues at link.

Copyright: © 2004 William M. Gray. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abbreviations: ABA, abscisic acid; ARF, auxin response factor; BR, brassinosteroid; GA, gibberellin; HK, histidine kinase; IAA, indole-3-acetic acid; JA, jasmonic acid; SCF, SKP1/Cullin/F-box protein

Citation: Gray WM (2004) Hormonal Regulation of Plant Growth and Development. PLoS Biol 2(9): e311
Phytohormones: What Are they?

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Non host resistance.

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