Non-destructive characterization of grafted tomato root systems using the mini-horhizotron

D.H. Suchoff, B.E. Jackson, C.C. Gunter, J.R. Schultheis, F.J. Louws
Root system morphological and architectural characteristics play a critical role in a plant’s ability to utilize substrate resources. Unfortunately, viewing and quantifying root system activity in potted plants is exceedingly difficult and traditionally done through destructive harvests. This method only allows for a snapshot of the plant root system at the time of harvest and gives no inference on the rate of root growth. Furthermore, this method can be highly destructive to the root system itself; many of the fine, high absorptive-capacity roots are lost during the cleaning process. The following study utilized the newly developed mini-horhizotron to non-destructively characterize root system morphology and architecture in grafted tomato (Solanum lycopersicum L.). Root tip density, speed of horizontal root growth, and total root length in the commercially available tomato scion (‘Tribute’) and two rootstock cultivars (‘Maxifort’ and ‘RST-106’) were compared. The study was conducted and repeated twice in a heated greenhouse during the months of February and March, 2014. A total of eight grafted treatments were compared: non-grafted ‘Tribute’, ‘RST-106’, and ‘Maxifort’; self-grafted ‘Tribute’, ‘RST-106’, and ‘Maxifort’; and ‘Tribute’ grafted onto ‘RST-106’ and ‘Maxifort’. The ‘Maxifort’ rootstock produced root systems with up to 80% higher root tip density, 25% faster rate of horizontal root growth, and 35% increase in total root length compared to ‘Tribute’, with ‘RST-106’ rootstock being intermediate to the two. These observed differences in ‘Maxifort’ root systems may correlate to the increased yield and vegetative vigor reported in the literature when this rootstock is used in greenhouse and field production. Furthermore, results from this study indicate that the mini-horhizotron allows for sensitive and robust non-destructive data collection on root system traits.
Suchoff, D.H., Jackson, B.E., Gunter, C.C., Schultheis, J.R. and Louws, F.J. (2021). Non-destructive characterization of grafted tomato root systems using the mini-horhizotron. Acta Hortic. 1302, 209-214
DOI: 10.17660/ActaHortic.2021.1302.28
roots, rhizotron, herbaceous graft, grafting, Lycopersicum esculentum

Acta Horticulturae