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Phenotyping roots in darkness: disturbance-free root imaging with near infrared illumination
The sizes and the architectures of root systems are essential determinants of plant performance and need to be assessed in high-throughput plant phenotyping platforms. Thus, a concept was tested, which involves near-infrared (NIR) imaging of roots growing along surfaces of transparent culture vessels using special long pass filters to block their exposure to visible light. Two setups were used to monitor growth of Arabidopsis, rapeseed, barley, and maize roots upon exposure to white light, filter-transmitted radiation or darkness: root growth direction was analyzed (1) through short term cultivation on agar plates and (2) using soil-filled transparent pots to monitor long-term responses. White light-triggered phototropic responses were detected for Arabidopsis (setup 1), rape seed (setups 1, 2), and barley roots (setup 2), while light effects could be avoided by use of the NIR filter thus confirming its suitability to mimic darkness. NIR image-derived ‘root volume’ values correlated well with root dry weight. The root system fractions visible at the different pot sides revealed species- and genotype-dependent variation of spatial root distribution. Following this proven concept, root imaging setups may be integrated into shoot phenotyping facilities in order to enable root system analysis in the context of whole plant performance investigations.
FP17262 Accepted 30 October 2017
© CSIRO 2017