Plants need auxin in order to grow. However, at its roots it inhibits growth. Researchers at IST Austria in Klosterneuburg have discovered a mechanism by which roots can react to obstructions and find suitable soil.
With their study published in the specialized journal Nature, the research group is essentially expanding knowledge about root growth, which can help agriculture find more productive plants, according to the Institute of Science and Technology (IST) Austria in Klosterneuburg ( Tulane area).
Auxin slows down and accelerates as needed
Auxin can slow or speed up the rapid growth of plant roots. The roots grow on winding paths around stones and smooth their way into wet areas, explains the research group from Klosterneuburg. By hardening cell walls, auxin stifles growth. It is driven by the relaxation of cell boundaries.
A team led by Jiri Friml of IST Austria allowed the roots of the cress plant (Arabidopsis thaliana) to thrive in transparent, liquid-filled chambers and observed them under a microscope. The researchers wrote: “We increased the level of auxin and immediately saw how the roots stopped growing. After we washed off the auxin, they grew again within seconds.”
They say auxin makes the plant walls acidic to soften them. To do this, they activate molecular pumps (H + -ATPases) that transfer positively charged hydrogen ions (H +), which are part of each acid, to the cell walls. Through alternative signaling pathways, auxin in turn can cause H+ ions to be expelled and make cell walls more basic and harder. Exactly how this works is not yet known. With the help of these two mechanisms, auxin can quickly and accurately control plant root growth in the challenging world of soil.
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