Climate change and global warming are realities nobody can deny. Today, it is important to feed the world at lower costs. An international team of researchers led by biologists at the University of Bristol in the UK has 'shown how to increase the length of root hairs on plants, potentially improving crop yields, as plants with longer root hairs take up minerals and water more efficiently.' Very interesting approach, but read more...
You can see on the left two images showing root hairs of plants. The top image is an interesting artist rendering showing how this research work would help to feed developing countries, including Africa. (Credit: University of Bristol) The photo below represents "a diagram of the root showing the arrangement of cells and root hairs, with the general directions of auxin flow shown in pink." (Credit: Angharad Jones, University of Bristol) Here is a link to the original versions of these images.
Before going further, what is auxin? According to Wikipedia, "auxins are a class of plant growth substance (often called phytohormone or plant hormone)." Here are more details about auxins provided by Eric Kramer, a physicist at Bard College at Simon's Rock, Massachusetts, who provided the computer model to calculate where auxin was likely to be in plants.
Here are some details provided by Kramer. "Auxin is a plant hormone that has been implicated in most aspects of plant development. It is synthesized in growing leaves and buds, transported downward through the stem and roots, and has additional effects in the tips of growing roots. Recent progress in cell and molecular biology has clarified many key aspects of auxin synthesis, transport and signaling."
Even if Kramer provided the computer model to the other scientists, he was not the lead researcher. This was Angharad Jones, a PhD student who is working under the supervision of Dr Claire Grierson at the School of Biological Sciences of the University of Bristol.
Now that you know what are auxins, let's read a comment by Jones about this research project. "Each root hair is a single, elongate cell and the length of each hair depends on having an adequate supply of the plant hormone auxin. Auxin is used, for example, in hormone rooting powders to encourage cuttings to root. The difficulty has been in understanding how auxin is delivered to the root hairs in order to promote their growth."
This is why the team used a computer model built by Kramer "to calculate where auxin was likely to be in plants. The model was based on current knowledge of auxin transport through and around the relevant cells. What the model showed was very surprising: auxin is not delivered to root hair cells directly, but via the cells next door which act as canals through which the auxin is transported. During transport, some of the auxin leaks out, supplying hair cells with the auxin signal to grow. This new understanding will be crucial in helping farmers to produce food sustainably and to reduce fertiliser waste, which can cause severe damage to ecosystems."
Here is an additional comment from Claire Grierson. "This important new work is an example of 'integrative biology', an innovative, interdisciplinary approach that uses experimental results alongside mathematical models and computer simulations to test ideas that are difficult or impossible to investigate with experiments alone. This approach has produced groundbreaking and surprising insights into a biological mechanism that might otherwise have eluded us."
For more information, this research work has been published online on December 14, 2008 in the Nature Cell Biology journal under the title "Auxin transport through non-hair cells sustains root-hair development." Here is an excerpt from the abstract. "The plant hormone auxin controls root epidermal cell development in a concentration-dependent manner. Root hairs are produced on a subset of epidermal cells as they increase in distance from the root tip. Auxin is required for their initiation and continued growth, but little is known about its distribution in this region of the root. [...] Experimental data support the hypothesis that instead of moving uniformly though the epidermal cell layer, auxin is mainly transported through canals that extend longitudinally into the tissue."
If you want to read the full article, it will cost you US$18.
Sources: University of Bristol press release, December 14, 2008; and various websites
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