Reason exploration for soil aeration promoting photosynthate transportation between sink and source in sweet potato

Abstract

Field experiments were performed using the varieties of starchy sweet potato Shangshu 19 and Jixu 23 with three treatments including loose soil, control soil and compact soil, to clarify the regulatory mechanism of soil compaction on transportation of photosynthates between sink and source of sweet potato. Compared with control treatment, storage root yield and economic coefficient of loose soil treatment were significantly increased by 27.03%–38.74% and 6.30%–13.05% in two years, respectively, while those of compact soil treatment significantly decreased by 17.87%–15.92% and 10.83%–15.63%, respectively. The 13C labeling results of functional leaves showed that loose treatment significantly improved the import efficiency of photosynthate in storage roots. Loose soil treatment significantly increased sucrose and starch contents in storage roots, but significantly reduced starch content in aboveground organs, especially in lower-middle position of stem. Compact soil treatment significantly decreased sucrose and starch contents in storage roots, but significantly increased starch and sucrose contents in aboveground organs especially in lower-middle position of stem. Both difference of sucrose content between stem base and stem top and between stem base and storage root at 50–1 50 d ays after planting in loose treatment were significantly decreased. While, significantly increased in compact treatment. The variation range of sucrose content difference between stem base and storage root was larger than between stem base and stem top. There was a very significantly negative correlation between the sucrose content difference of stem base and storage root, and the sucrose and starch content in storage root. Improvement of soil aeration, can promote the transportation of photosynthates from stem base to storage root, increase carbohydrate content in storage root and enhance storage root yield.