Carbon-14 labelled sucrose transportation in an Arabidopsis thaliana using an imaging plate and real time imaging system

As an approach to increased production of rape seed oil from Brassica napus L., Arabidopsis thaliana, a species from the same Brassicaceae family, was used to investigate transport behavior and distribution of matter in the plant body. In this study, sucrose, an initial metabolic product of photosynthesis, labeled with carbon-14 was used. The sucrose was applied to A. thaliana via the surface of a rosette leaf. Using the real time radioisotope imaging system we developed and an imaging plate (IP), images of whole or part of the sample were obtained. The sucrose assimilation products were accumulated in maturing tissue such as flowers and fruits, and in a joint part. From the comparison among branches and stems, it was indicated that there were different patterns of demand and distribution of sucrose assimilation products depending on the tissue and its growing stage. This might be caused by either morphological reason such as diameter and location of the sieve tube, or genetic factors such as an activity of a membrane transport protein. Because of self-absorption of carpels, it was difficult to observe the accumulation of carbon-14 in the seeds inside the fruits; however, an IP image of a frozen section of a fruit revealed that carbon-14 transport to seeds was higher than that of carpels. These methods will help us gain insight into matter transport and strategies to improve the production of rape seed oil. (author)