The root is the below-ground organ of a plant, and it has evolved multiple signaling pathways that allow adaptation of architecture, growth rate, and direction to an ever-changing environment. Roots grow along the gravitropic vector towards beneficial areas in the soil to provide the plant with proper nutrients to ensure its survival and productivity. In addition, roots have developed escape mechanisms to avoid adverse environments, which include direct illumination. Standard laboratory growth conditions for basic research of plant development and stress adaptation include growing seedlings in Petri dishes on medium with roots exposed to light. Several studies have shown that direct illumination of roots alters their morphology, cellular and biochemical responses, which results in reduced nutrient uptake and adaptability upon additive stress stimuli. In this review, we summarize recent methods that allow the study of shaded roots under controlled laboratory conditions and discuss the observed changes in the results depending on the root illumination status.

Department of Experimental Plant Biology Faculty of Science Charles University 128 00 Prague Czech Republic

Department of Functional and Evolutionary Ecology Molecular Systems Biology Faculty of Life Sciences University of Vienna Djerassiplatz 1 1030 Wien Austria

Laboratory of Hormonal Regulations in Plants Institute of Experimental Botany Czech Academy of Sciences 165 02 Prague Czech Republic

Vienna Metabolomics Center University of Vienna Djerassiplatz 1 1030 Wien Austria

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Recent insights into metabolic and signalling events of directional root growth regulation and its implications for sustainable crop production systems

Throttling Growth Speed: Evaluation of aux1-7 Root Growth Profile by Combining D-Root system and Root Penetration Assay