施氮对铜镉污染土壤中大豆植株生长及氮磷钾含量的影响

Effect of nitrogen application on the growth and nitrogen,phosphorus,and potassium content of soybean plants in copper and cadmium polluted soil

土壤重金属污染加剧使农业生产受到严重威胁,为提高土地重金属污染治理效率,针对施氮能否缓解土壤重金属污染对植物的毒害作用开展研究。通过开展盆栽实验,分别测定大豆植株的生长指标、营养含量和重金属含量,研究施氮对镉(Cd~(2+)4mg/L)和铜(Cu~(2+)16mg/L)污染土壤中大豆植株生长的影响。结果表明:施氮使铜、镉污染土壤中的大豆株高分别增加了43.38%和47.67%,生物量增加了162.01%和218.69%。在含4mg/LCd~(2+)土壤中,施氮使大豆植株根、茎、叶中的氮含量增加120.20%、138.25%和10.21%;根、叶中的磷含量分别上升了66.93%、10.75%,茎部的磷含量下降13.46%;根、茎、叶中的钾含量分别上升了10.97%、37.36%、47.49%;而根、茎、叶中的Cd含量分别降低了50.53%、78.28%、42.31%。在含16mg/LCu~(2+)土壤中,施氮使大豆根、茎、叶中的氮含量分别增加了64.52%、135.71%、55.48%;磷含量分别下降了79.72%、80.30%、43.71%;钾含量分别增加了39.31%、61.43%、104.69%;同时大豆根部的Cu含量降低了48.91%,而茎、叶中的Cu含量无显著变化。综上,施氮可通过促进植物生长,增强其抗逆性,从而缓解土壤重金属污染的毒害作用。

Agricultural production has been seriously threatened by intensification of heavy metal pollution in soil.To improve the utilization efficiency of heavy metal polluted land,this paper mainly answered the scientific question whether nitrogen application could alleviate the toxicity of heavy metals on plants.The effects of nitrogen application on soybean plants in cadmium(Cd2+4mg/L)contaminated soil and copper(Cu2+16mg/L)contaminated soil were detected by carrying out pot experiment,measuring growth,nutrition and heavy metal content of soybean plants.The results showed that plant heights were increased by 43.38%and 47.67%,biomass were increased by 162.01%and 218.69%,respectively.In soil containing 4mg/LCd2+,nitrogen content in roots,stems and leaves of soybean plants increased by 120.20%,138.25%and 10.21%.Phosphorus content in roots and leaves increased by 66.93%and 10.75%but decreased by 13.46%in stems.Potassium content in roots,stems and leaves increased by 10.97%,37.36%and 47.49%.And Cd content in roots,stems and leaves decreased by 50.53%,78.28%and 42.31%respectively.In soil containing 16 mg/LCu2+,nitrogen application increased nitrogen content in soybean roots,stems and leaves by 64.52%,135.71%and 55.48%,decreased phosphorus content by 79.72%,80.30%and 43.71%,increased potassium content by 39.31%,61.43%and 104.69%.Meanwhile,Cu content in roots decreased by 48.91%and not significantly changed in stems and leaves.To summarize,this paper showed that nitrogen application could promote plant growth and enhance stress resistance ability of plants,thus alleviating the toxicity of heavy metals in soil.