Chlorophyll fluorescence: New Instruments for Special Applications

Abstract

During the past decade there has been remarkable progress in the understanding and practical use of chlorophyll fluorescence in plant science (1,2,3). This progress has resulted from fruitful interactions between three different research disciplines: basic research (dealing with the dynamics of excitation transfer, photochemical charge separation and electron transport), applied research (making use of fluorescence as an noninvasive tool) and the development of new instruments and methodology, to measure fluorescence and to extract the essential information from it. In particular, with the introduction of pulse-amplitude-modulated (PAM) fluorometers and the saturation pulse method of quenching analysis (4), chlorophyll fluorescence has gained widespread applications. It provides manifold information at various levels of the complex process of photosynthesis, starting from light absorption, energy transfer and primary energy conversion, and ending with the export of assimilates from the chloroplast. Due to its large signal amplitude, chlorophyll fluorescence traditionally has been a pioneering tool in photoynthesis research. Making use of recent progress in optoelectronics and microprocessor/computer technology, a new generation of chlorophyll fluorometers with extreme sensitivity and selectivity has been developed, the essential features of which will be outlined in the present communication.