施氮对镉胁迫下山杨幼苗叶片氮磷钾吸收及镉积累量的影响

Effect of Nitrogen Supplement on N,P,K Uptake and Cd Accumulation in Leaves of Populus davidiana under Cadmium Stress

为探究山杨在重金属镉胁迫与增施外源氮复合处理条件下的生长及元素积累差异,该研究以山杨幼苗为材料,通过盆栽实验研究在重金属镉(Cd)胁迫下增施外源氮(N)对其形态、叶绿素、淀粉和可溶性糖含量、叶片中全氮(N)、全磷(P)、全钾(K)以及Cd含量的影响。结果表明:(1)单独Cd处理显著抑制山杨幼苗的叶片宽度和茎粗;施加外源N能够缓解Cd胁迫对植株的毒害,其叶长、叶宽和茎粗较单独Cd处理显著增加。(2)单独Cd处理后山杨叶片的叶绿素含量和淀粉含量均比对照显著下降,而其可溶性糖含量显著增加;与单独Cd处理相比,Cd+N复合处理后山杨的叶绿素含量显著增加,淀粉含量却显著下降,而可溶性糖含量略有降低。(3)与对照相比,单独Cd处理后,山杨叶片全N含量显著下降,全P含量显著增加;单独N和Cd+N复合处理后叶片全N含量均显著增加,全P含量均显著下降;全K含量在各处理下均无显著差异。(4)在Cd胁迫下山杨幼苗叶片的Cd含量比对照极显著增加,且Cd+N复合处理后叶片的Cd含量约是单独Cd处理的2倍。研究认为,增施氮素处理可显著提高山杨幼苗对镉胁迫环境的适应能力以及叶片对镉的富集能力。

In order to explore the difference of growth and element accumulation of Populus davidiana seedlings under the combined of compound treatment of cadmium(Cd)and exogenous nitrogen(N),we studied the effects of N on morphology,chlorophyll,starch and soluble sugar contents,total nitrogen(N),total phosphorus(P),total potassium(K)and Cd content in leaves under Cd stress by pot experiment.The results showed that:(1)the leaf width and stem diameter of P.davidiana were significantly inhibited by Cd alone.The toxicity of Cd to plants was compensated by exogenous N under Cd stress,and the leaf length,leaf width and stem diameter were significantly increased compared with Cd treatment alone.(2)Compared with the control,the chlorophyll content and starch content of P.davidiana leaves decreased significantly after Cd treatment,while the soluble sugar content increased significantly.Compared with Cd+N treatment,the chlorophyll content increased significantly,the starch content decreased significantly,and the soluble sugar content decreased slightly.(3)Compared with the control,the total N content and total P content of P.davidiana leaves decreased significantly after Cd treatment.The total N content increased significantly and the total P content decreased significantly after N treatment and Cd+N combination treatment.However,there was no significant difference in total K content among all treatments.(4)Under Cd stress,the Cd content in leaves of P.davidiana seedlings was significantly increased compared with the control,and the Cd content in leaves of Cd+N composite treatment was about twice as much as that of single Cd treatment.The results showed that the adaptability of P.davidiana seedlings and Cd accumulation ability of leaves could be improved by increasing N application under Cd stress.