Response of photosynthate distribution in potato plants to different LED spectra.

Although light is essential to photosynthesis, few studies have examined the effects of different LED spectra on photosynthate distribution in potato plants. Therefore, we exposed tuberising potato plants to white (W), red (R), blue (B) and green (G) LED treatments and compared tuber development and carbohydrate partitioning among the plants. R-treated plants had greater photosynthetic leaf area during tuber development compared with those under other treatments, thus enhancing assimilation. Although R-treated plants had higher 13C assimilation in the leaves, stems and roots than those under B treatment, there was no difference in partitioning of 13C assimilation and yield in the tubers of each plant between R and B treatments. For the tuber size, R-treated plants had a higher ratio of large tubers (>20 g) and a lower ratio of small (2-20 g) and medium-sized (10-20 g) tubers than those under W. B-treated plants had more medium-sized and large tubers than those under W. The reason may be that plants under R treatment distributed more assimilated 13C in their first tuber than those under other treatments. By contrast, plants under B balanced photosynthate distribution among their tubers. Leaves under G treatment had lower photosynthetic efficiency and ΦPSII than those under W, R or B treatment, which resulted in lower 13C photosynthate allocation in organs and lower tuber yield per plant than in R and B treatments. Overall, R treatment promoted 13C assimilation and led to more large tubers than other treatments. B-treated plants distributed more photosynthates into tubers rather than other organs and showed balanced tuber development.