改善土壤通气性促进甘薯源库间光合产物运转的原因解析

为了明确土壤通气性对甘薯源库间光合产物运转的调控机制,本研究以淀粉型品种商薯19和济徐23为试验材料,设置疏松、对照和紧实3个处理进行大田试验,研究结果表明,与对照处理相比,疏松处理显著提高2个品种的块根产量和经济系数, 2年平均增幅分别为27.03%～38.74%和6.30%～13.05%,紧实处理则显著降低2个品种的块根产量和经济系数, 2年平均降幅分别为17.87%～15.92%和10.83%～15.63%。功能叶13C标记结果显示,疏松处理显著提高块根中光合产物的输入效率。疏松处理显著提高块根中蔗糖和淀粉含量,显著降低地上部器官中淀粉含量和茎中尤其是茎的中下部中蔗糖含量;紧实处理则显著降低块根中蔗糖和淀粉含量,而显著提高地上部器官蔗糖和淀粉含量,且茎中下部蔗糖含量增幅较大。疏松处理显著降低50～150d茎基部与茎顶部间和茎基部与块根间的蔗糖含量差;紧实处理则显著提高茎基部与茎顶部间和茎基部与块根间的蔗糖含量差,且茎基部与块根间蔗糖含量差的变幅大于茎基部与茎顶部间的蔗糖含量差。相关分析表明,茎基部与块根间、茎基部与茎顶部间蔗糖含量差与块根蔗糖和淀粉含量呈极显著负相关。说明改善土壤通气性可促进茎基部光合产物向块根的运转,提高块根中碳水化合物含量,增加块根产量。

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

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 50-150 days 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.