DRY-MATTER PARTITIONING DURING THE PROPAGATION OF HIPPEASTRUM-HYBRIDUM AS AFFECTED BY LIGHT

Dry matter partitioning was investigated in bulbils propagated from twin-scales and in 1-year-old bulbs of Hippeastrum hybridum (cv. Apple Blossom) under different light regimes. Irrespective of the light regimes imposed there was a steady decrease in the dry weight and starch of the scales used for bulbis propagation. The dry weight and leaf area of bulbils propagated in continuous darkness were lower than of those of continuous light and dark-light treatments. When dark-grown bulbils were transferred to the light (dark-light treatment) their leaves greened rapidly and expanded to the size of those grown in continuous light. In the initial phase of development, bulbs of plants from 1-year-old bulbs functioned as an efficient source of assimilates for shoot and root growth. Starch reserves and sucrose were mobilized for the growth of roots and leaves. This flux was reversed when the plants reached the 50th day after planting in full light, and the 75th day after planting in 50% light, indicating that the bulbs changed from being sources to sinks.