稀土元素处理对甘蔗体内氮素同化作用的影响研究

本文报道应用稀土元素处理甘蔗（Soccharum officinarum L.)叶片，分析测定了硝态氮、氨态氮、总氮、游氨基酸组分及游离氨基酸含量、硝酸还原酶（NR）活性等变化以及NR活性与硝态氮含量的关系。研究稀土元素处理对甘蔗体内氮素同化作用的影响。结果表明，应用100－600ppm稀土元素处理甘蔗叶片均能不同程度地减少其硝态氮含量，提高其氨态氮、总氮、游离氨基酸总含量以及NR活性，但游离氨基酸组分没发生变化，各处理浓度中以300ppm处理的效果为最显著，高浓度稀土元素处理则呈抑制效应。甘蔗叶片硝态氮含量与叶片NR活性具有平行关系，即凡硝态氮含量高，NR活性也高，凡硝态氮含量低，NR活性也低，以上结果，说明一定浓度范围的稀土元素处理能促进甘蔗的氮素同化作用。

STUDIES ON THE EFFECT OF RARE EARTH ELEMENTS ON NITROGEN ASSIMILATION IN SUGARCANE (Saccharum officinarum L. )

This paper reports studies on the effect of rare earth elements (REE) on nitrogen assimilations in the sugarcane. After foliar application of REE to sugarcane plants in 5 different concentrations, change in the contents of nitrate nitrogen, ammonium nitrogen, total nitrogen, free amino acid, free amino acid composition, nitrate reductase (NR) activity were determined. The experimental results showed that, treating sugarcane leaves with REE at 100-600 ppm concentrations, could in varying degrees decrease the content of nitrate nitrogen and Increase the contents of ammonium nitrogen, total nitrogen, free acid and NR activity, this tendency being most apparent at the 300 ppm concentration. High concentrations, however, exhibited opposite effects. REE treatment In sugarcane decreased the content of nitrate nitrogen and increased that of ammonium nitrogen, being consistent with previous reports that NR activity increased after REE treatment. That is to say, NR activity was positively correlated with nitrate nitrogen. No change was found in the free amino acid composition at different concentrations of REE in the leaves of the sugarcane, but the free amino acid content varied rather much, notably with the 300 ppm treatment These results showed that nitrogen assimilation in the sugarcane could be promoted by certain concentrations of REE treatment,