SIMULTANEOUS ASSESSMENT OF PHOTOSYNTHETICALLY ACTIVE AND ULTRAVIOLET SOLAR-RADIATION

A new dosimetric package for assessing solar radiation affecting photo synthesis in the visible and ultraviolet wavebands in plant canopies h as been developed and tested. The package consists of several detector s sensitive to Various wavebands between 290 and 700 nm. For photosynt hetically active radiation (PAR), the dosimeter was calibrated for exp osures in terms of photosynthetically active photons between 0.003 mol m(-2) and 0.38 mol m(-2). The package allows simultaneous assessment of the irradiances across the visible and ultraviolet wavebands. Over a plant canopy, the biologically effective ultraviolet radiation varie d by approximately a factor of 2 compared to a Variation by approximat ely a factor of 14 in the photosynthetic photon flux density. (C) 1998 Elsevier Science B.V. All rights reserved.