稀土元素对植物的生物效应及其作用机理

综述了稀土元素对植物根系发育、生物量、品质和抗逆性的影响.适量稀土浓度可促进植物生长，提高种子萌发能力和根系发育，提高植物生物量，并改善植物果实的品质.施用适量稀土元素还可以增强植物的抗逆性并且对一些植物病害有一定防治作用.介绍了植物对稀土元素的吸收特性和稀土元素在植物体内的含量、分布、存在形式及细胞定位.重点探讨了稀土元素对植物光合作用、叶绿素形成、植物吸收营养元素、稀土元素与钙相关性和稀土元素对细胞膜及酶的作用机理，内容包括稀土元素可提高植物叶绿素含量，增强光合效率，从而增加植物生物量.适量的稀土元素能够促进植物对营养元素的吸收、转化和利用.稀土元素有类似钙的功能，可置换出酶中的钙离子而参与酶的反应.稀土离子可以维持细胞膜的透性和稳定性，提高膜的保护功能，增强植物对不良环境的抵御能力.最后，对稀土元素的研究前景进行了展望.

Biological effects of rare earth elements and their action mechanisms

This paper reviewed the effects of rare earth elements on plant root development, biomass, quality, and resistance against stress. Applying appropriate amount of rare earth elements could not only promote seed germination and root development, increase plant biomass, but also improve harvest quality and plant resistance against stress. The plant uptake characteristics of rare earth elements, as well as their contents, distribution, existing forms, and cytolocalization in plants were discussed, with the focus on the effects of rare earth elements on photosynthesis and chlorophyll formation, nutrient uptake, relationships between rare earth elements and calcium, and action mechanisms of rare earth elements on ceil memhrane and enzymes. Rare earth elements could enhance chlorophyll content and improve photosynthetic rate, and thus, could increase plant biomass. When an appropriate amount of rare earth elements was applied, the uptake of nutrients by plant and their transformation and utilization were promoted, Rare earth elements could replace calcium ion to participate in enzymatic reactions, maintain the osmosis and stability of cell membrane, promote the protection function of cell membrane, and enhance the plant resistance capability against stress, In the end, further researches on rare earth elements were suggested.