Alboresi A, Gestin C, Leydecker M-T, Bedu M, Meyer C, Truong H-N
Unité de Nutrition Azotée des Plantes, INRA centre de Versailles-Grignon, Versailles Cedex, France.
Plant Cell Environ. 2005 Apr;28(4):500-12. doi: 10.1111/j.1365-3040.2005.01292.x.
Nitrate is an important nitrogen source for plants, but also a signal molecule that controls various aspects of plant development. In the present study the role of nitrate on seed dormancy in Arabidopsis was investigated. The effects of either mutations affecting the Arabidopsis nitrate reductase genes or of different nitrate regimes of mother plants on the dormancy of the seeds produced were analysed. Altogether, data show that conditions favouring nitrate accumulation in mother plants and in seeds lead to a lower dormancy of seeds with little other morphological or biochemical differences. Analysis of germination during seed development indicated that nitrate does not prevent the onset of dormancy but rather its maintenance. The effect of an exogenous supply of nitrate on seed germination was tested: nitrate in contrast to glutamine or potassium chloride clearly stimulated the germination of dormant seeds. Data show, moreover, that the Arabidopsis dual affinity nitrate transporter NRT1.1 (CHL1) may be involved in conveying the nitrate signal into seeds. Thus, nitrate provided exogenously or by mother plants to the produced seeds, acts as a signal molecule favouring germination in Arabidopsis. This signalling may involve interaction with the abscisic acid or gibberellin pathway.
硝酸盐是植物重要的氮源，也是控制植物发育各个方面的信号分子。在本研究中，对硝酸盐在拟南芥种子休眠中的作用进行了研究。分析了影响拟南芥硝酸还原酶基因的突变或母本植物不同硝酸盐处理方式对所产生种子休眠的影响。总体而言，数据表明，有利于硝酸盐在母本植物和种子中积累的条件会导致种子休眠降低，且几乎没有其他形态或生化差异。对种子发育过程中萌发情况的分析表明，硝酸盐不会阻止休眠的开始，而是会阻止休眠的维持。测试了外源供应硝酸盐对种子萌发的影响：与谷氨酰胺或氯化钾相比，硝酸盐明显刺激了休眠种子的萌发。此外，数据表明，拟南芥双亲和性硝酸盐转运蛋白NRT1.1（CHL1）可能参与将硝酸盐信号传递到种子中。因此，外源提供或由母本植物提供给所产生种子的硝酸盐，作为一种信号分子，有利于拟南芥种子的萌发。这种信号传导可能涉及与脱落酸或赤霉素途径的相互作用。
