三种植物对土壤磷吸收和富集能力的比较

Comparison of phosphorus uptake and accumulation capacity among three plant species

筛选磷富集植物是磷矿废弃地土壤与植被修复的关键。该文以向日葵(Helianthus annuus)、苏丹草(Sorghum sudanense)、南瓜(Cucurbita moschata)为研究对象,采用盆栽试验,设置5个磷浓度(0、100、300、500和700 mg·kg–1),分别在3个不同生长时段(4周、7周、10周)内采样,对这3种植物的磷吸收和富集能力进行了比较。结果表明:(1)在相同生长时间内,向日葵、苏丹草、南瓜的地上部磷含量均随磷处理浓度的升高而增大,最大值分别为9.67 g·kg–1、4.86 g·kg–1、6.32 g·kg–1;相同浓度下,向日葵地上部磷含量随着生长时间的延长呈上升趋势,苏丹草则呈下降趋势,南瓜无显著变化;(2)3种植物的地上部磷累积量均在磷处理浓度为700 mg·kg–1时,生长10周后达到最大值,分别为217.83 mg·plant–1、93.92 mg·plant–1、135.82 mg·plant–1;(3)各浓度处理下,向日葵、苏丹草的地上部磷富集系数和转移系数均大于1.00,南瓜的地上部磷富集系数和转移系数波动较大;向日葵的富集系数和转移系数最大值分别达11.39和4.09。综合比较可知,3种植物磷吸收和富集能力的大小顺序为:向日葵>南瓜>苏丹草。向日葵各项富磷特征基本符合磷富集植物的筛选标准,可作为磷矿废弃地土壤与植被修复的备选物种。

Aims Phosphorus mining wasteland is a very special kind of degraded ecosystems,where vegetation and landscape are severely damaged. Our objective was to select plants suitable for phytoremediation of phosphorus-rich soils in mining wasteland.Methods We conducted pot experiments to investigate phosphorus uptake and accumulation capacity in Helianthus annuus,Sorghum sudanense and Cucurbita moschata grown in soils with different levels of phosphorus supply. The phosphorus concentrations applied are 0,100,300,500 and 700 mg·kg^–1. Phosphorus concentration,phosphorus accumulation,bioaccumulation and translation coefficient of the plants were measured for three growth periods（4 weeks,7 weeks,10 weeks）,respectively. Important findings Over the same growth period,phosphorus concentration in shoots of the three plant species increased with increasing phosphorus supplies,with the maximum of 9.67 g·kg^–1 in H. annuus,4.86 g·kg^–1 in S. sudanense,and 6.32 g·kg^–1 in C. moschata. Under the same phosphorus treatments,phosphorus concentration significantly increased with growth time in shoots of H. annuus,decreased in shoots of S. sudanense,and did not significantly change in shoots of C. moschata. The aboveground total phosphorus accumulation in the three plant species all reached highest values when grown for 10 weeks in soils supplied with 700 mg·kg^–1 phosphorus,amounting to 217.83 mg·plant–1 in H. annuus,93.92 mg·plant^–1 in S. sudanense,135.82 mg·plant^–1 in C. moschata,respectively. The bioaccumulation and translation coefficients in both H. annuus and S. sudanense exceeded 1.00 under each treatment. The peak values of the two coefficients were 11.39 and 4.09 for H. annuus. In conclusion,the phosphorus uptake and accumulation capacity of the tested plant species were in the order of H. annuus C. moschata S. sudanense,and H. annuus can be a possible candidate for phytoremediation of phosphorus mining wastelands.