Phenotyping Techniques for Deep Rooting under Abiotic Stress

PhD defence by Si Chen

Summary: ​

Roots play an essential role in plant growth and responses to abiotic stress. Root traits are related to the water and nutrient uptake ability of root system. Particularly, deep rooting trait enables plants to use deep soil resources and improve crop yield in water-limited conditions. However, it is a challenge to study roots as they are hidden in the soil. Root phenotyping method is need to be explored and improved for better understanding of root traits and breeding purposes.

This study evaluated the reliability of six deep root phenotyping techniques in a series of five experiments during 2014 and 2015. Among these methods, the 15N tracer method had much higher ability to distinguish the genotypes and more promise for future upscaling for plant breeding. The 15N tracer method was further used to detect genotypic variations of deep rooting trait under drought stress in a field-like facility. The deep rooting genotypes generally had higher 15N uptake and 15N uptake was related to root depth. Root depths estimated by the 15N tracer method were in agreement with the values measured by minirhizotrons. The 15N tracer method was demonstrated to be was useful and efficient to detect genotypic variations of deep rooting traits. In addition, 15N tracer was applied to study root recovery after waterlogging stress. Interestingly, root and shoot growth seemed to compensate for short-term waterlogging by growing adventitious roots above the waterlogged zone, and increasing photosynthetic parameters and root growth after drainage.​

Supervisors: ​​

Professor Kristian Thorup-Kristensen, Crop Sciences, PLEN
Associate Professor Dorte Bodin Dresbøll, Crop Sciences, PLEN

Assessment committee:

Associate Professor Fulai Liu, Crop Sciences, PLEN
Professor Mathias Neumann Andersen, Aarhus University
Professor Xavier Draye, Université catholique de Louvain, BE

​Reception after the defence in the Canteen​​