Source–sink manipulations differentially affect carbon and nitrogen dynamics, fruit metabolites and yield of Sacha Inchi plants

Abstract Background Being a promising tropical woody oilseed crop, the evergreen and recurrent plants of Sacha Inchi ( Plukenetia volubilis L.) has complex phenology source–sink interactions. Carbon manipulations with control two treatments (reduce source, ca. 10% mature leaf pruning; reduce sink, fruitlet thinning) were conducted on 2.5-year-old field-grown P. plantation during early-wet season in seasonal area. Results Leaf photosynthetic rate specific area largely remained unchanged response to defoliation or defloration. Compared control, higher N contents average observed both remaining leaves branches defoliated plants, suggesting that N-mobilization was mainly due enhanced uptake from soil. Carbon, but not N, is source-driven growth process as reduced non-structural carbohydrates (especially sugar) branches, although temporally, whereas defloration increased available C reserve. The dynamic pattern fruit ripening altered by regulations. Total seed yield throughout growing season, which depends set retention (i.e., number matured fruit) rather than individual development (size), slightly significantly decreased defoliation. did enrich KEGG pathway, downregulated TCA cycle carbohydrate lipid metabolisms fruitlets after 24 days applications manipulation. Conclusion Carbohydrate reserves serve buffer sink–source imbalances may result temporary adjustment demand for assimilates (e.g., defloration) shortfalls carbon assimilation defoliation). Defoliation disadvantageous also accumulation fruits plants. Although more studies are needed, these results provide new insights further improvement strong source-limited source/sink manipulations.