植物液泡中硝酸盐行为的研究概况

化学氮肥利用率低和损失严重而造成的环境污染问题是农业生态系统中氮素管理首当其冲要研究和解决的问题 ,这方面的研究工作在国内外报道浩如烟海 ,但突破性进展不多。另一方面 ,植物体内的硝酸盐含量高又严重影响农产品有关的品质性状 ,特别是我国加入WTO后蔬菜和果实中高含量的硝酸盐是影响这些产品出口的主要限制因子之一。因此 ,从植物体本身着手研究植物氮素高效利用的机理与途径 ,这是近几年来植物氮素营养研究的热点之一。植物液泡占据了成熟植物细胞体积的 90 %左右 ,而液泡和细胞质中硝酸盐的浓度通常分别在 30～ 5 0molm- 3和 3～ 5molm- 3,因此 ,如何调动植物液泡中的硝酸盐使之得到更高程度的再利用 ,这是提高植物氮素利用效率和降低植物体内硝酸盐含量的途径之一。本文综述了国内外有关液泡中硝酸盐行为的研究状况 ,在此基础上作者首次提出植物液泡中硝酸盐的内外流与植物氮素高效利用之间可能存在着密切的关系 ,旨在拓始这方面的工作能尽快开展 ,为植物氮素高效利用的分子生物学研究开辟新的研究领域。

A REVIEW ON THE BEHAVIOR OF NITRATE IN VACUOLES OF PLANTS

There have been many papers reported on low use efficiency of chemical N fertilizer and its loss leading to environmental pollution but very few ones are found to have advanced achievements.High contents of nitrate in some plants, especially in vegetables and fruits, decrease significantly the qualities of these plants, thus becoming one of the limiting factors for the exporting of the products.Studies on the mechanisms and ways to high use efficiency of N in plant itself have become one of the issues in plant N nutrition in the last a few years.Vacuoles occupy about 90% of the total volume in matured cells of plants and the concentrations of nitrate in vacuoles and cytosol are normally 30~50 mol m^-3 and 3~5 mol m^-3, respectively.Therefore, it is one of the ways to increase the N use efficiency and decrease the contents of nitrate in plants that the nitrate in vacuoles are remobilized and reutilized.The present paper reviews the main studies on the behavior of nitrate in vacuoles.The author proposes in the first time that there should be some close relat ionships between the influx and efflux of nitrate though tonoplasts and N use efficiency in plants.The author also on purpose initiates the research work of this field in China by exposing some issues to be considered.