施镍对玉米苗期氮、磷吸收的影响

Responses of Corn Seedling Uptake Nitrogen/Phosphorus on Excessive Nickel and Its Mechanism

采用室内盆栽方法,研究了不同土壤施镍量对玉米苗期生长、土壤脲酶活性和磷酸酶活性及植株吸氮、磷量的影响,初步探讨了其机理。结果表明:随着施镍量的增加,玉米苗期干质量和鲜质量降低。当施镍量<100 mg/kg时,施镍量与植株根长相关性不显著,当施镍量>100 mg/kg时,根长与施镍量呈负相关。当土壤施镍量<100 mg/kg时,施镍量与玉米吸氮量无显著相关性,施镍量>100 mg/kg时,施镍量与植株氮含量呈负相关。土壤施镍量与植株吸磷量呈负相关,并且当施镍量<200 mg/kg时,随着施镍量的增加植株吸磷量显著降低。土壤镍过量会严重抑制玉米植株生长发育。这可能是因为土壤施镍量的增加抑制了植株对氮、磷的吸收,降低了土壤脲酶活性及磷酸酶活性,并影响了植株根系生长及细胞膜的离子交换。

Pot incubation method was used to study the effects of different concentrations of Ni ＋ stress on content of nitrogen and phosphorus, growth of maize seedlings and soil enzyme activity, and its mecha- nism was preliminarily discussed. The results showed that fresh and dry weight of maize seedlings in- creased initially and then decreased with applied nickel increasing. When Ni was lower than 100 mg/kg, the concentration of Ni ＋ stress did not have a significant correlation with root length of maize seedlings. When Ni was higher than 100 mg/kg, the concentration of Ni ＋ stress was inversely related to root length of maize seedlings. When Ni was lower than 100 mg/kg, the concentration of Ni~ stress did not have a significant correlation with the uptake of nitrogen. When Ni was higher than 100 mg/kg, the concentration of Ni ＋ stress was inversely related to the uptake of nitrogen too. The concentration of Ni stress was in- versely related to the uptake of phosphorus. When the concentration of Ni ~ stress was lower than 200 mg/ kg, the uptake of phosphorus by corn seedling was reduced significantly. High levels of Ni in soil could inhibit the growth of corn seedling. The increase of nickel rate inhibits nitrogen and phosphorus uptake of plant tissue. It also reduces soil enzyme activity and preliminary activity. In addition, the increase of nickel rate influences plant root growth and ion exchange of cell membrane.