Effect of various chemical agents on photosynthesis studied by the method of fluorescence induction

Slow fluorescence induction (SFI) in bean and wheat leaves was observed under illumination by wide-band blue light after 5 min dark period. The F-M/F-T ratio was used as a main parameter of SFI, where F-M is a maximal, and F-T is a steady-state level of fluorescence. Leaves were treated by various chemical agents: herbicide diuron, activator of photosynthesis, inorganic phosphate, and different mineral supplements. It is shown that there is a high positive correlation between F-M/F-T ratio of SFI and the stationary photosynthetic activity of the leaf. It is concluded that the SFI-method makes it possible to study as short-and long-time changes in photosynthetic apparatus influenced by various physiologically active compounds. (C) 1998 Elsevier Science B.V. All rights reserved.