The miniPPM-300 is latest and most advanced version of our plant photosynthesis meter. The instrument can automatically measure photosynthesis-light curves of plants, thus providing information on optimum light level for growth and the corresponding photosynthesis and dry matter production. To this end the instrument creates a series of user defined light levels on the leaf. At each level the instrument waits for leaf adaptation and then carries out a photosynthesis rate measurement. All measuring data are included in a measuring report that is generated automatically, thus providing an easy way of documentation. An example of the measuring report is presented below.