SHOOT/ROOT RATIO OF CUCUMBER IS AFFECTED BY ENVIRONMENTAL CONDITIONS
Root growth of cucumber is often believed to limit shoot growth and yield. It is generally accepted that the dry matter distribution between shoots and roots follows the principle of functional equilibrium, although the underlying mechanism of this is still not understood. This study aimed to investigate the effects of various environmental conditions on the biomass distribution between the shoots and the roots of hydroponically grown greenhouse cucumbers. In all experiments, treatments were adjusted when the plants reached the 10th leaf stage. Plants were topped after 20 to 25 leaves. After all fruits on the main stem had been harvested, the experiments were terminated, and the root and shoot characteristics were recorded. CO2 concentration and the nutrient solution pH did not affect shoot/root or leaf/root ratios. However, the leaf/root ratio increased significantly with increasing air temperature and with increasing root zone temperature while it decreased with increasing radiation. The strong increase in shoot/root and leaf/root ratios with rising temperature goes against data from many other species such as tomato. Results are discussed in relation to model approaches for dry matter distribution in plants. Neither the allometric nor the functional-equilibrium approach can explain the observed phenomena. Further work will be necessary to understand the mechanism of dry matter allocation in plants.
Kläring, H.-P. and Kyuchukova, M.A. (2007). SHOOT/ROOT RATIO OF CUCUMBER IS AFFECTED BY ENVIRONMENTAL CONDITIONS. Acta Hortic. 731, 143-151
allometry, dry matter distribution, functional equilibrium, leaf/root ratio