Modeling temperature-modulated stem growth of cucumber plants (Cucumis sativus L.)

Variation in temperature has tremendous effects on plant growth and development. Below optimal conditions, a decrease in temperature can result in both, a reduced organ appearance rate and a reduced organ growth rate. For internode growth, the latter also depends on the light signal, which in turn might be altered by the temperature effect on the canopy. The aim of this work was to analyze the importance of both, temperature and light signals for a precise prediction of stem growth. Therefore, we (i) investigated the temperature effects on the main stem of greenhouse grown cucumber plants and (ii) used an extended functional-structural plant model of cucumber, L-Cucumber, to analyze the effects of temperature x light on cucumber stem growth. Data of a greenhouse experiment with 24, 20, 16 day temperature (°C) were used for model parameterization. Organ appearance on temperature sum basis rate was significantly reduced just in case of the lowest temperature condition, whereas average internode lengths decreased with temperature. The simulation scenarios highlighted the role of both characteristics on predicting final internode lengths (FILs) and showed how light and temperature both effect on FILs. However, the presented model concept needs to be properly evaluated. Future research should investigate the timing and duration of the temperature sensitive time window for internode growth.