在荷格兰德氏 ( Hoagland)营养液中加入系列浓度的硝酸镧处理烟草苗 ,采用 ICP- MS(电感耦合等离子体质谱 )测定烟草中稀土含量 ,结果表明 :( 1)处理的烟草幼苗中稀土含量分布为根 >叶 >茎 ;( 2 )烟草体内各部位的稀土含量均随外源稀土量的增加而增加。L a( NO3) 3对烟草叶绿体光合作用中光化学反应的影响试验结果证实 :L a( NO3) 3在低浓度范围内 ( 5～ 2 0 mg/L) ,对烟草叶绿体希尔反应、光合磷酸化速率及叶绿体膜 Mg2 +- ATP酶活力均有明显的促进作用 ,且随其浓度增加作用效果加强 ,最佳浓度为 10～ 2 0 mg/L ;但随 L a( NO3) 3处理时间的延长 ,其作用效果逐步下降 ;高浓度的 La( NO3) 3对烟草叶绿体希尔反应、光合磷酸化速率及叶绿体膜 Mg2 +- ATP酶活力均有明显的抑制作用 ,且随处理时间的延长其抑制程度加强 Tobacco seedlings were treated with lanthanum nitrate at a concentration of Hoagland nutrient solution, and the content of rare earth in tobacco was determined by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that: (1) The content of rare earth was root> leaf> stem. (2) The content of rare earth in all parts of tobacco increased with the increase of exogenous rare earth. Effects of L a (NO3) 3 on Photochemical Reaction in Photosynthesis of Tobacco Chloroplasts The results showed that L a (NO3) 3 in the low concentration range (5 ~ 20 mg / L) And the activity of Mg2 + - ATPase in chloroplast membrane were significantly enhanced, and the effect was enhanced with the increase of its concentration, the optimum concentration was 10 ~ 20 mg / L; however, with the treatment of L a (NO3) 3 Prolonged, and its effect decreased gradually. High concentration of La (NO3) 3 significantly inhibited Hill reaction, photosynthetic phosphorylation rate and chlorophyll Mg2 + - ATPase activity in tobacco leaves. With the prolongation of treatment time, Inhibition increased