Analysis of translocation and distribution of photoassimilates in eggplant fruit using a positron-emitting tracer imaging system

Kikuchi, Kaori*; Ishii, Satomi; Kawachi, Naoki; Suzui, Nobuo; Fujimaki, Shu

In the eggplant cultivation, defoliation is normally used to prevent the disease and insect as well as to raise the efficiency of light interception for efficient fruit production. However, the general guideline for defoliation is not established yet because fundamental knowledge about effects of defoliation on the nutritional balance in individuals has hardly been obtained. For these reason, it is important to clarify the translocation mechanism of the photoassimilates from each leaf to the fruit in eggplant. Previously, we succeeded in observation of translocation of C-labeled photoassimilates from a leaf into a fruit and established a method for the quantitative analysis of the translocation rates and velocities using a positron-emitting tracer imaging system (PETIS). PETIS can noninvasively visualize the movement of C-labeled photoassimilates in plants, and thus repetitive experiments with one plant are possible due to the short half-life (20 min) of C. In this study, we analyzed translocation of photoassimilates in eggplant from each of the three major neighboring leaves to a fruit of interest, and estimated the respective contributions to the fruit growth using CO and PETIS.