硝酸镧、硝酸铈对细茎石斛组培苗生长的影响

Effects of La(NO_3)_3 and Ce(NO_3)_3 on the Growth of Dendrobium moniliforme Plantlets in vitro

【目的】研究不同浓度的硝酸镧、硝酸铈对细茎石斛组培苗生长的影响,为稀土元素在组培上的应用提供依据。【方法】采用组培技术,以未添加硝酸镧、硝酸铈的石斛组培苗为对照,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0.2mg/L硝酸镧和0.2～0.4mg/L硝酸铈促进效果最佳。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0.2mg/L)降低了石斛组培苗叶绿素b和总叶绿素含量,且对叶绿素a的促进仅见于0.2mg/L;低浓度硝酸铈(0.2～1mg/L)均能增加叶绿素a、叶绿素b和总叶绿素含量,高浓度则反之。【结论】稀土硝酸盐对石斛组培苗生长、叶绿素含量具有一定作用,浓度的高低是抑制(促进)生长、叶绿素合成的关键因子。

[Objective] To provide theoretical basis for the use of rare-earth in vitro, the study was made on the effects of different concentrations of La（NO3）3 and Ce（NO3）3 on the growth of Den- drobium monili forme plantlets in vitro. [Method] With Dendrobium monili form plantlets in vitro without adding La（NOa）3 or Ce（NO3）3 as control, the test was carried out by tissue culture technology to determine the medium with the concentration of rare-earth compounds. [Results] The results showed that low concentration of 0.2 mg/L La（NO3）3 or 0.2--0.4 mg/L Ce（NO3）3 could significantly promote the growth of Dendrobium moniliforme plantlets in vitro. High con- centration of La（NO3）3, Ce（NO3）3 had negative effects on the growth of Dendrobium monili- forme, and even led to death. The effects of two kinds of rare earth nitrate on the total of chloro- phyll were significantly different. La（NO3）3 （except 0.2 mg/L） reduced the content of chloro- phyll b and the total of chlorophyll, but promoted the content of chlorophyll a on the point of 0.2 mg/L. Low concentration of Ce（NO3）3 （0.2--1 mg/L） promoted the content of chlorophyll a and chlorophyll b and the total of chlorophyll, while the effect of high concentration was just oppo- site. [Conclusion] Rare-earth nitrate has some impacts on the growth of tissue culture seedlings and the chlorophyll content of Dendrobium moniliforme. The content is the key factor for limit- ing or promoting growth and chlorophyll synthesis.