Hormone causes dividing plant cell to rebel

Mar 28, 2014 by Prof.dr. D (Dolf) Weijers
An embryo showing the two cotyledons (seed leaves) starting to develop at the top. Cells are coloured according to a colour scale whereby large volumes are shown in red and small volumes in blue.

Cell division in plants is governed by a physical law. A law that was postulated in the 19th century and tested in a two-dimensional plane many times after that. In an article published in the top journal Developmental Cell on 27 March, researchers from Wageningen University show that the law applies equally in 3D. However, the plant hormone auxin then breaks this law, steering growth to generate the organised plants we all know and love.

Plants grow because cells divide. Biologists have been observing the patterns of cell division ever since the invention of the microscope. In the second half of the 19th century, the patterns scientists observed inspired them to formulate simple 'rules' that explained the patterns of cell division. Perhaps the most famous rule is the one formulated by Leo Errera in 1888, which dictates that plant cells divide like soap bubbles. They take the shortest path by forming a partition straight across the middle of the cell. The shape of the cell (the geometry) therefore determines the new division plane.

Plant embryo development in 3D

Although rules like this are commonly applied (in simulation models for , for example), until now they have only ever been tested in the two dimensions that make up the flat plane. In a study carried out in the Laboratory of Biochemistry, Wageningen researcher Professor Dolf Weijers and his team accurately imaged very young plant embryos in three dimensions. They did this by refining an existing 3D method for analysing plant embryos. The simulation models subsequently developed can be used to prove whether cells divide according to the 'shortest path' principle or not.

Flouting the rules

This video is not supported by your browser at this time.

"Some divisions certainly follow this standard rule", explains Dolf Weijers, "but others do not!" The researchers discovered that cell divisions that deviate from this norm always result in two different types of cells. "It is an asymmetric division", he continues. "But to our surprise, these divisions turned out to be controlled by a ; the auxin hormone." When the researchers deactivated this hormone, all the cells suddenly divided according to the standard rule. The research team therefore concluded that the hormone auxin enables cells to ignore the standard rule.

These findings shed new light on the function and effect of the important hormone auxin in the development of plants. "The main question is how the hormone manages to make the rebel in this way", says Weijers. "Although we have not answered this question yet, at least we now know that there is a question to answer".

Controlling is an important first step in the development of new organs in . The researchers hope that learning more about how this process works will help them to devise new strategies for advancing plant growth.

Explore further: Scientists unveil a molecular mechanism that controls plant growth and development

add to favorites email to friend print save as pdf

Related Stories

Unearthing key function of plant hormone

Feb 28, 2014

Plants, like animals, employ hormones as messengers, which coordinate growth and regulate how they react to the environment. One of these plant hormones, auxin, regulates nearly all aspects of plant behavior and development, ...

Pushy neighbour sends several messages

Mar 30, 2010

How does a plant ensure that one cell remains responsible for making root cells for the rest of its life? The plant embryo contains the transcription factor MONOPTEROS. This tells its neighbouring cell to become a centre ...

Recommended for you

Bitter food but good medicine from cucumber genetics

7 hours ago

High-tech genomics and traditional Chinese medicine come together as researchers identify the genes responsible for the intense bitter taste of wild cucumbers. Taming this bitterness made cucumber, pumpkin ...

New button mushroom varieties need better protection

11 hours ago

A working group has recently been formed to work on a better protection of button mushroom varieties. It's activities are firstly directed to generate consensus among the spawn/breeding companies to consider ...

Cataloguing 10 million human gut microbial genes

Nov 25, 2014

Over the past several years, research on bacteria in the digestive tract (gut microbiome) has confirmed the major role they play in our health. An international consortium, in which INRA participates, has developed the most ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.