Defoliation and S nutrition on radish: growth, polyphenols and antiradical activity

Resumo

Experiments were carried out to study patterns of artificial defoliation in radish (Raphanus sativus L.) in combination with sulphur (S) fertilization, to evaluate the contribution of younger and older leaves on plant growth and phenolics accumulation in storage roots. Biomass accumulation and partitioning were related to leaf age, magnitude and timing of the clipping treatments. Older leaves increased biomass production and translocation into the storage organ; besides, they induced higher accumulation of phenolic compounds compared to the younger leaves. The highest S fertilization rate (120 kg S ha^-1) significantly enhanced the polyphenols accumulation, as well as the antiradical activity. The modulation of S inputs in combination with slightly induced stress from defoliation could effectively enhance the concentration of some important phytochemicals, providing higher nutritionally improved vegetables, without affecting yield.