S08 - Session P5 - Effects of light quality environments on nutrient absorption in leafy vegetables

Authors: Kazuki Serizawa *, Keiko Ohashi-Kaneko

Light quality during cultivation affects the physiological functions of plants. In the rice plants grown under red light supplemented with blue light, photosynthetic rates per unit leaf area measured under white light were higher than those in the plants grown under red light. The higher photosynthetic rates were associated with higher total N content of leaves. Blue light must be promoting the uptake of N from the roots. We speculated that the absorption of the essential nutrient elements of plants other than N may also be affected by the light quality. In this study, we investigated the effect of light quality on nutrient concentrations in some leafy vegetables grown in the artificial lighting plant factory. Komastuna ( Brassica rapa 'hamami-2gou'), spinach ( Spinacia oleracea L. 'Neo-cyclone'), leaf lettuce ( Lactuca sativa Green-wave) were grown under red light or blue light at a PPFD of 150 μmol m -2 s -1 for few weeks. The concentrations of N, P, Ca, Mg, Fe, Mn, Zn and Na in each organ at harvest were measured with ICP-OES analysis. In the komatsuna plants, most of the essential nutrient element contents in each organ were greater under blue light irradiation than under red lightirradiation. In the leaf lettuce plants, the N, Ca and Mn contents in the roots of the plants grown under red light compared to blue light were greater, while those contents in the leaves of the plants grown under blue light were greater than those under red light. The Ca and Mn contents in the leaves of the spinach plants grown under red light were greater than those under blue light. We will report on the details of the relationship between light quality and the contents of the essential nutrient elements of plants from the results of principal component analysis and cluster analysis.