Related Experiment Video
Updated: Jun 1, 2026
07:57
Quantification of Endogenous Auxin and Cytokinin During Internode Culture of Ipecac
Published on: March 15, 2018
A mutually inhibitory interaction between auxin and cytokinin specifies vascular pattern in roots
Anthony Bishopp1, Hanna Help, Sedeer El-Showk
1Institute of Biotechnology and Department of Biosciences, University of Helsinki, FIN-00014 Helsinki, Finland.
Current Biology : CB
|May 31, 2011
Summary
Plant organ patterning relies on a feedback loop between auxin and cytokinin. This hormonal interaction establishes distinct signaling domains, guiding vascular development in Arabidopsis roots and enabling continuous organ connections.
Area of Science:
- Plant developmental biology
- Hormonal signaling in plants
- Arabidopsis thaliana research
Background:
- Plants exhibit iterative growth, continuously producing new organs from meristems, unlike animals with predetermined body plans.
- Understanding organ patterning in plants is crucial for comprehending their unique developmental strategies.
- Arabidopsis thaliana embryos establish bisymmetry in cotyledon specification, which extends to the root promeristem.
Purpose of the Study:
- To investigate the mechanisms underlying organ patterning in plant development.
- To elucidate the roles of auxin and cytokinin in establishing bisymmetric vascular patterns.
- To understand how hormonal feedback loops influence plant morphogenesis.
Main Methods:
- Analysis of hormonal feedback loops involving auxin and cytokinin.
- Investigating the role of PIN-FORMED (PIN) auxin efflux proteins.
- Studying the regulation of cytokinin signaling inhibitor AHP6.
- Observing vascular pattern specification in Arabidopsis embryonic roots.
Main Results:
- A mutually inhibitory feedback loop between auxin and cytokinin was identified.
- Cytokinins regulate PIN protein distribution, creating a central auxin domain.
- High auxin levels induce AHP6, inhibiting cytokinin signaling and completing the loop.
- This hormonal loop specifies bisymmetric protoxylem differentiation and vascular patterns in embryonic roots.
Conclusions:
- Hormonal signaling and transport feedback loops propagate small hormonal biases into distinct signaling domains.
- This mechanism specifies vascular patterns in the root meristem.
- Such feedback loops may enable radial pattern transformation and continuous vascular connections between new organs.
Related Concept Videos
01:56Plant Hormones
Plant hormones—or phytohormones—are chemical molecules that modulate one or more physiological processes of a plant. In animals, hormones are often produced in specific glands and circulated via the circulatory system. However, plants lack hormone-producing glands.
01:56Plant Hormones
Plant hormones—or phytohormones—are chemical molecules that modulate one or more physiological processes of a plant. In animals, hormones are often produced in specific glands and circulated via the circulatory system. However, plants lack hormone-producing glands.
02:26Responses to Gravity and Touch
Gravitropism: Plant Responses to Gravity
03:02Primary and Secondary Growth in Roots and Shoots
Vascular plants, which account for over 90% of the Earth’s vegetation, all undergo primary growth—which lengthens roots and shoots. Many land plants, notably woody plants, also undergo secondary growth—which thickens roots and shoots.
02:34Water and Mineral Acquisition
Specialized tissues in plant roots have evolved to capture water, minerals, and some ions from the soil. Roots exhibit a variety of branching patterns that facilitate this process. The outermost root cells have specialized structures called root hairs that increase the root surface, thus increasing soil contact. Water can passively cross into roots, as the concentration of water in the soil is higher than that of the root tissue. Minerals, in contrast, are actively transported into root cells.
01:46The Apoplast and Symplast
Plant growth depends on its ability to take up water and dissolved minerals from the soil. The root system of every plant is equipped with the necessary tissues to facilitate the entry of water and solutes. The plant tissues involved in the transport of water and minerals have two major compartments - the apoplast and the symplast. The apoplast includes everything outside the plasma membrane of living cells and consists of cell walls, extracellular spaces, xylem, phloem, and tracheids. The...