Duckweed is a kind of floating aquatic plant and increasing its starch production is favorable for bioenergy. In this study, we found that starch biosynthesis was greatly promoted by the supplement of nickel ion (Ni²⁺) through the comparison of other different ions. The starch content in duckweed was increased by nearly eightfold when duckweed was treated with 20 µM Ni²⁺. The analysis of paraffin sections visually found that starch granules were more complete and dark blue in Ni²⁺ treated duckweed than the control. Quantitative real-time PCR demonstrated that the expressions of starch synthesis-related enzymes were up-regulated in Ni²⁺ treated duckweed. Further analysis revealed that the accumulation of Ni²⁺ in duckweed effectively increased the activity of urease, which compensated for the deficiency of certain decrease in biomass and accelerated biosynthesis of the starch. Thus, our results represent another strategy to improve starch production of duckweed.

浮萍是一种漂浮的水生植物，增加其淀粉产量有利于生物能源。在这项研究中，我们发现通过比较其他不同离子，镍离子（Ni ²⁺）的添加极大地促进了淀粉的生物合成。用20 µM Ni ²⁺处理浮萍时，浮萍中的淀粉含量增加了近八倍。目视石蜡切片的分析发现，与对照相比，Ni ²⁺处理的浮萍中的淀粉颗粒更完整，呈深蓝色。实时定量PCR表明，在Ni ²⁺处理的浮萍中淀粉合成相关酶的表达上调。进一步分析表明，Ni ²⁺的积累浮萍中有效地增加了脲酶的活性，弥补了生物量的某些下降和淀粉的生物合成加速的不足。因此，我们的结果代表了另一种提高浮萍淀粉产量的策略。