外源稀土Ce3+对凤眼莲钙相关光合作用的影响

以造成水体污染的主要水生生物之一的凤眼莲为研究对象,探究外源稀土Ce3+对凤眼莲钙相关光合作用的影响.相比于对照组,营养液中缺钙但添加外源稀土Ce3+的条件下,凤眼莲叶绿素含量减少8.31%、叶绿体荧光产额分别减少6.14%(440nm)和3.82%(480nm)、类囊体膜上Mg2+-ATP酶和Ca2+-ATP酶分别减少1.93%和5.05%,蛋白质含量减少3.94%;但较缺钙的营养液处理组相应指标分别增加了9.89%、15.21%和3.05%、8.08%和10.26%、10.16%.添加Ce3+的营养液处理组的凤眼莲钙相关光合作用指标同样显著提高.结果表明,Ce3+有类似于Ca2+的特性,适量的Ce3+可以补偿替代钙,对植物光合作用有促进效果,增加植物生物量,促进凤眼莲型水生植物的生长,对水体富营养化进程的发展起正催化作用.

Influences of rare earths (Ce3+) on calcium-regulated photosynthesis in Eichhornia crassipes

Influences of rare earth Ce3+ on calcium-regulated photosynthesis in Eichhornia crassipes were investigated. When cultured in Ce3+-containing nutrient solution without Ca2+, the chlorophyll produced in Eichhornia crassipes was found to decrease by 8.31% compared to that of counterparts cultured in Ca2+-containing nutrient solution (control experiment). The corresponding fluorescence quantum yields of chloroplast at 440and 480nm were also decreased by 6.14% and 3.82%, respectively. Additionally, the activities of Mg2+-ATP enzyme and Ca2+-ATP enzyme, and the amount of proteins were also decreased by 1.93%, 5.05% and 3.94%, respectively. However, the above parameters related to the calcium-regulated photosynthesis increased by 9.89%, 15.21%, 3.05%, 8.08%, 10.26% and 10.16%, respectively, when compared with those of Eichhornia crassipes cultured in nutrient solution without Ca2+. The photosynthesis activity of Eichhornia crassipes cultured in the absence of Ca2+ had been significantly improved by the use of rare earth Ce3+. The experimental results have shown that compared with Ca2+, Ce3+ exhibited similar regulation functions on the growth of Eichhornia crassipes. In the absence of Ca2+, a suitable amount of Ce3+ will promote the photosynthesis of plant by increasing the plant biomass, thus resulting in positive catalytic effects on the process of eutrophication.