Institut für Allgemeine Botanik der Universität, Saarstr. 21, D-6500 Mainz, Federal Republic of Germany.
J Plant Physiol. 1984 May;115(2):115-24. doi: 10.1016/S0176-1617(84)80058-9. Epub 2012 Feb 20.
Chlorella fusca was grown autotrophically in undiluted cultures over a period of seven days under two different light intensities (5, 26 W · m(-2)) and under four concentrations of vanadate (1, 20, 100, 500 μg·l(-1)) in the nutrient medium. It was shown that vanadium enhances the chlorophyll content under both light conditions depending on the age of the cultures. A stimulating effect of vanadium on the dry weight production and the photosynthetic activity can be observed only in strong light. In a second series of experiments, cells were grown under homocontinuous conditions. In this case the chlorophyll content · l(-1) suspension was kept constant by automatic dilution at a very low cell density. The results demonstrate that vanadium enhances the ratio of chlorophyll per dry weight only in low light. The light saturating curves show that vanadium induces a higher photosynthetic activity in high light, but not in low light. Vanadium stimulates the productivity in strong light by 50%. The ratio of P-700 per 1000 chlorophylls rises from 1.4 to 2.0 in high light and from 0.9 to 1.2 in low light. Contrary to this, the quotient cytochrome f per 1000 chlorophylls is affected only in high light. It runs up from 2.6 to 4.8. In a third experimental run, the measurements were repeated when EDTA (20 μmol·l(-1)) was added to the nutrient medium. It is shown that EDTA can reduce the effects of sublethal iron stress, which is the condition when the vanadium effect becomes most obvious. Under conditions of facilitated iron uptake the vanadium effect on photosynthesis, P-700 and cytochrome f disappears. The regulation capacity of vanadium on the photosynthetic apparatus is discussed on the basis of the variability of the photosynthetic unit. It is shown that vanadium can be used as an environmental factor to control different components of the photosynthetic apparatus in a different way. The photosynthetic capacity and the content of cytochrome f are strongly correlated; on the other hand, P-700 is changed independently from photosynthesis. This gives evidence to define the PSU as the ratio of chlorophyll to cytochrome f.
富营养化小球藻在为期七天的两个不同光照强度（5、26 W·m（-2））和四个浓度的偏钒酸盐（1、20、100、500 μg·l（-1））下进行了自养培养。结果表明，钒在两种光照条件下都能根据培养物的年龄来提高叶绿素含量。只有在强光下才能观察到钒对干重产量和光合作用的刺激作用。在第二组实验中，细胞在同质连续条件下生长。在这种情况下，通过自动稀释将叶绿素含量·l（-1）悬浮液保持在非常低的细胞密度下保持恒定。结果表明，钒仅在弱光下提高每干重的叶绿素比。光饱和曲线表明，钒在高光下诱导更高的光合作用，但在低光下则不然。钒在强光下将生产力提高了 50%。每 1000 个叶绿素的 P-700 比例从高光下的 1.4 上升到 2.0，从低光下的 0.9 上升到 1.2。与此相反，每 1000 个叶绿素的细胞色素 f 比值仅在高光下受到影响。它从 2.6 上升到 4.8。在第三个实验中，当向营养培养基中添加 EDTA（20 μmol·l（-1））时，重复了测量。结果表明，EDTA 可以减轻亚致死铁胁迫的影响，这是钒效应最明显的条件。在促进铁吸收的条件下，钒对光合作用、P-700 和细胞色素 f 的影响消失。根据光合单位的可变性，讨论了钒对光合器官的调节能力。结果表明，钒可用作环境因素，以不同的方式控制光合器官的不同组成部分。光合能力和细胞色素 f 的含量密切相关；另一方面，P-700 与光合作用无关。这证明了可以将 PSU 定义为叶绿素与细胞色素 f 的比值。
