Plant Reaction to Heat: The Head is in the Soil A case of communication between root and shoot
Plants also react to heat. In an international collaboration, scientists from the University of Strasbourg, the University of Valencia (UPV), and the Technische Universität Braunschweig discovered that at elevated temperature plants regulate growth via their roots. These fundamental findings of communication between roots and shoots could help improving cultivation methods under environmental changes. The results were published in the journal “Nature Plants”.
“If it gets warm, the root releases a precursor of the signaling molecule gibberellin, that the shoot utilizes to produce hormones promoting growth, a phenomenon known as thermomorphogenesis,” says Dr. Maria João Pimenta Lange and Professor Theo Lange from the Institute of Plant Biology at TU Braunschweig.
Arabidopsis thaliana was the model plant used for this study. In Strasbourg, genetic experiments were conducted with shoots of hormone deficient mutants grafted onto roots of wild type plants. These plant constructs were grown at 20°C and 28°C, respectively. By this approach it was demonstrated that the roots produce a hormone precursor which transport into the shoot increases at elevated temperatures. Once in the shoot, the precursor enables the growth hormone to be synthesized and growth happens.
Flexible growth regulation at temperature changes
These studies explain the hormonal basis of thermomorphogenesis: The root to shoot transport of a hormone precursor ensures flexible regulation of growth in case of temperature changes.
Elevated vegetative growth in ornamental plants or herbs production is often unwanted. In agriculture to much growth can lead to yield losses, for example lodging damages due to the collapse of the cereal stem. Rising temperatures as a result of climate change might promote such scenarios dramatically. This research offers a possible solution to this problem: a cool root – achieved, for example, by intelligent irrigation strategies – could offer yield security even at rising temperatures.
Camut L, Regnault T, Sirlin-Josserand M, Sakvarelidze-Achard L, Carrera E, Zumsteg J, Heintz D, Leonhardt N, Pimenta Lange MJ, Lange T, Davière J-M, Achard P. Root-derived GA12 contributes to temperature-induced shoot growth in Arabidopsis. Nature Plants, DOI: 10.1038/s41477-019-0568-8.