Use of Green Fluorescent Protein (GFP) to Determine the Influence of Competition On Root Dynamics.

Studying root dynamics and belowground plant-plant interactions is essential for understanding the composition of plant communities, the impact of global change and terrestrial biogeochemistry. While most soil samples and minirhizotron pictures hold roots of more than one plant individual, information about root affiliation to plant individuals is decisive to determine competitive interactions.We grew transgenic Zea mays plants, expressing green fluorescent protein (GFP), in isolation and in mixture with non-transformed plants in a greenhouse. Using a special minirhizotron system able to detect GFP fluorescence and a VIS minirhizotron camera, the root systems were taped weekly to determine root growth and longevity. Pictures were analyzed, separated by local competitive situation, using WinRhizo Tron. GFP expressing and non-GFP plants were easily distinguished by the strong, green fluorescence of transgenic roots as compared with minor autofluorescence in non-GPF roots. The differences in root dynamics and longevity under competition and in isolation, and the future use of GFP for studies on root dynamics are discussed. The stable expression of GFP in crop plants allows conducting advanced studies on intra- and interspecific competition in monocultures and inter-cropping systems. Future studies should use GFP expressing plants to determine spatial and temporal rooting pattern in agricultural mixtures in situ. GFP expressing and non-GFP plants can be easily distinguished by the strong, green fluorescence of transgenic roots as compared with minor autofluorescence. The stable expression of GFP in crop plants allows for advanced studies on spatial and temporal rooting pattern in plant mixtures. GFP expressing and non-GFP plants can be easily distinguished by the strong, green fluorescence of transgenic roots as compared with minor autofluorescence. The stable expression of GFP in crop plants allows for advanced studies on spatial and temporal rooting pattern in plant mixtures.