Analysis of translocation and distribution of photoassimilates in eggplant fruit in relation to positions of the source leaves using the positron-emitting tracer imaging system

Kikuchi, Kaori*; Kawachi, Naoki; Ishii, Satomi; Suzui, Nobuo; Ito, Sayuri; Ishioka, Noriko; Honda, Ichiro*; Fujimaki, Shu

In the eggplant cultivation, defoliation is normally used to prevent the disease and insect as well as 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 accumulation mechanism of the photoassimilates which is translocated from each leaf to the fruit in eggplant. Previously, we succeeded to observe translocation of C-labeled photoassimilates from a leaf into a fruit and established a method for the quantitative analysis of photoassimilates using the positron-emitting tracer imaging system (PETIS). PETIS can noninvasively visualize the movement of C-labeled photoassimilates in plants and repetitive analyses using one plant are possible due to the short half-life (20 min) of C. In this study, we analyzed translocation of photoassimilates from each of major leaves to a fruit, and estimated the contribution of the respective leaves to accumulation of photoassimilates in the fruit using CO and PETIS.