[ Objective ] To study the effects of different concentration of La( NO3), and Ce( NO3) 3 on growth of Dendrobium moniliforme plant-lets in vitro. [Method] Different concentration of La (NO3), and Ce(NO3)3 were added into the culture medium to observe their impact on the growth, rooting and chlorophyll content in Dendrobium, moniliforme plantlets, their best addition concentration was determined. [Result] Low concentration of rare earth nitrate could promote the growth of plantlete, especially 0. 2 mg/L La( NO3 )3 and 0.2 -0.4 mg/L Ce( NO3)3. While high concentration of rare earth nitrate produced adverse impact and even cause the death of plantlets. La( NO3) 3 and Ce (NO3) 3 had diverse influences on chlorophyll content, La( NO3)3(especially 0.2 mg/L) reduced the content of chlorophyll b and total chlorophyll in Den-drobium moniliforme plantlets, but promoted the content of chlorophyll a at the content of 0.2 mg/L. while Ce(NO3)3(0.2 -1 mg/L) could significantly increase the content of chlorophyll a, chlorophyll b and total chlorophyll at low concentration, but inhibit their contents at high concentration. [ Conclusion ] Rare earth nitrate could promote the growth of plantlets at low concentrations, while inhibit their growth and even cause their death al high concentration.%[目的]研究不同浓度的硝酸镧和硝酸铈对细茎石斛组培苗生长的影响.[方法]将不同浓度硝酸镧和硝酸铈添加于细茎石斛培养基中,观察其对组培苗生长、生根和叶绿素含量的影响,确定培养基中添加稀土硝酸盐的最佳浓度.[结果]低浓度稀土硝酸盐能促进组培苗生长,其中0.2 mg/L硝酸镧和0.2～0.4 mg/L硝酸铈的促进效果最佳.高浓度稀土硝酸盐对细茎石斛组培苗生长表现为负效应,甚至导致死亡.两稀土硝酸盐对叶绿素含量影响差异较大,硝酸镧(除0.2 mg/L)降低了石斛组培苗叶绿素b和总叶绿素的含量,且对叶绿素a的促进仅见于0.2 mg/L;低浓度硝酸铈(0.2～1 mg/L)均能增加叶绿素a、叶绿素b和总叶绿素含量,高浓度则抑制.[结论]低浓度稀土硝酸盐能促进组培苗的生长;高浓度稀土硝酸盐抑制组培苗的生长,甚至导致死亡.
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