铁对三角褐指藻生长、光合作用及生化组成的影响

近来许多研究表明,不论是在无机氮丰富还是贫乏的水域,铁元素的供应对于浮游植物的生物量、生长率、种类组成及初级生产力均会产生影响。通过室内培养,研究了铁对三角褐指藻生长、光合作用以及细胞生化组成的影响。实验结果表明,在其他营养盐充足的条件下,海水中铁浓度的变化对三角褐指藻的生长及光合作用均有显着影响。在5×10-7mol/dm3铁浓度时,三角褐指藻可达到其最大光合作用速率。在添加铁的条件下,三角褐指藻细胞多种生化组成受到不同程度的影响,其中叶绿素a含量变化幅度最大,增加了25%～35%,叶绿素c、类胡萝卜素含量也有一定程度的增加,但增长幅度要小于叶绿素a;碳水化合物的含量增加了5%～10%,蛋白质含量的增加幅度在5%～15%之间;超氧化物歧化酶(SOD)的活性及DCMU荧光增强比(F_d/F)也呈明显的增加趋势。铁是海洋初级生产过程中的一种限制因子。

The effects of iron on growth, photosynthesis and biochemical composition of a marine algae Phaeodactylum tricornutum

Iron supply has been proved to influence phytoplankton biomass, growth rate and species composition as well as primary productivity in both high and low NO3 water. The effect of iron on photosynthesis, growth, and biochemical composition of Phaeodactylum tricornutum is studied with laboratory culture. The results show that the algae growth and photooynthetic rate are affected Obviously by the concentration of iron, 5 X10-7 mol/dm3 seems to be the optimum saturated concentration of iron for photosynthesis. The content of biochemical component in Phdactylum tricornutum changes under different iron regimes. The increase of chl-a was most significant, ranges from 25% to 35%. Chl-c and carotenoids also increase at degrees less than that of chl-a. Carbohydrates and proteins increase by 5%-10% and 5%-15%, respectively. The activity of cell superoxide dismutase(SOD)and ratio of fluorescence before and after adding DCMU(Fd/F) also increase. Iron has been referred as a factor of limitation in primary productivity in the sea.