Effects of Mulching on the Activity of Acid Invertase and Sugar Contents in Japanese Radish

The effects of mulching on soil moisture and temperature and sugar metabolism in Japanese radish (Raphanus sativus L.) were studied. Soil moisture content and temperature were higher in mulched plots than the none-mulched plots throughout the experimental period. Radish roots grown in plots with mulch were heavier than those without one. Acid invertase activities in soluble fraction (SF) and cell wall-bound fraction (CWBF) of the roots grown in plots with and without mulch showed the same pattern. However, the enzyme activity was higher in roots grown in mulched plots. The acid invertase activity in SF gradually increased during growth and development while no specific inclining or declining pattern was found in CWBF. Mulching did not significantly affect the amount of fructose (Fru) and glucose (Glc) contents during growth and development. However, sucrose (Suc) content in roots grown in plots with mulch was higher than those grown without mulch throughout the experimental period. Fru and Glc contents in the bottom portion of the root were also found to have same pattern as the top portion. Present results suggest that mulching could increase crop yield by producing heavier root weight and improve product quality such as sweetness due to higher Suc content of the roots.