硒处理对斜茎黄芪生长生理和初生代谢的影响

以一种具有较高Se富集能力的植物——斜茎黄芪（Astragalus adsurgens）为试验材料，在水培条件下研究不同浓度Se处理对其生长发育、光合参数和初生代谢产物积累的影响。结果表明：5 μmol·L^-1 Se处理显著促进了斜茎黄芪根系和地上部的伸长生长；100 μmol·L^-1 Se处理则具有相反效果。光合色素含量和叶片叶绿素荧光参数研究结果与生长指标相一致，低浓度Se对斜茎黄芪叶片的光合作用具有促进作用，高浓度Se则对其具有明显的抑制作用。随着处理浓度的升高，斜茎黄芪根系和地上部Se含量逐渐增加，但Se的转运系数明显降低，100 μmol·L^-1处理下Se转运系数比5 μmol·L^-1处理降低了83.5%。通过对初生代谢产物进行检测和分析，发现低浓度Se处理主要上调了斜茎黄芪中与氨基酸代谢相关途径的代谢水平，而高浓度Se处理主要上调了与次生代谢物质合成关系密切的初生代谢产物的代谢水平。我们的研究结果表明，低浓度Se处理提高了斜茎黄芪光合作用水平以及与生长相关的初生代谢水平，从而促进了植株生长；高浓度Se处理下斜茎黄芪则通过降低Se向地上部的转运水平并将更多的初生代谢产物用于次生代谢产物的合成，从而提高了植株对Se胁迫的耐性。

Effects of Selenium Treatment on Physiology and Primary Metabolism of Astragalus adsurgens

In order to clarify the effects of different concentration Se treatments on the growth， development， photosynthesis and the primary metabolism of plant， Astragalus adsurgens， with high Se accumulation capacity under hydroponic condition was used as material. The results showed that different concentrations of Se had different effects on the growth and development of A. adsurgens. Low concentration Se treatment（5 μmol·L^-1） significantly promoted the growth of A. adsurgens， whereas high concentration Se treatment（100 μmol·L^-1） had the opposite effect. The content of Se in roots and shoots was positively correlated with the treatment concentration， and the transport coefficient of Se in A. adsurgens decreased gradually with the increase of selenium concentration. The results of photosynthetic pigment content and leaf chlorophyll fluorescence parameters showed that low-concentrations of Se promoted photosynthesis of A. adsurgens， while high-concentrations of Se significantly inhibited it， the Se transport coefficient under 100 μmol·L^-1 treatment decreased by 83.5% compared with 5 μmol·L^-1 treatment. After detection and analysis of primary metabolites， it was found that low concentrations of Se up-regulated the metabolic pathways related to amino acid metabolism in plant roots and shoots， while high concentrations of Se mainly up-regulated the metabolic levels of primary metabolites that were closely related to the synthesis of secondary metabolites. Our results showed that treatment with low concentration of Se increased the photosynthesis level of A. adsurgens and the level of primary metabolism related to growth， and promoted plant growth； treatment with high concentration Se increased the level of A. adsurgens by reducing the transport of Se to the ground and more primary metabolites for the synthesis of secondary metabolites were used， and the tolerance of plants to Se stress was improved.